Nuclear Physics Seminar, Fall 2017 / Spring 2018

The regular experimental and theoretical nuclear physics seminar take places Thursdays at 4h00PM. Lunch seminars are also held from time to time on the rest of the days at 1PM.

The venue is either the Gerry Brown Room (Physics Building, room C-133), or the Peter Paul Room (Physics Building, room C-120).

In addition to this seminar series, the Center for Frontiers in Nuclear Science (CFNS) organizes seminars twice a month (1st and 3rd Thursday of each month), which take place at Stony Brook University and BNL alternately. The schedule of the CFNS seminars can be found under the center's website, http://www.stonybrook.edu/cfns/.

For suggesting speakers, please contact juan.torres-rincon@stonybrook.edu.

Google Calendar version: https://calendar.google.com/calendar/embed?src=stonybrook.edu_v5puq1gb0braomja25hqhjnf5g%40group.calendar.google.com&ctz=America/New_York

(Calendar ID: stonybrook.edu_v5puq1gb0braomja25hqhjnf5g@group.calendar.google.com)


Fall 2017  
Time Speaker Title Host  Notes
June 11,
4h00PM Monday

(Room C133)
 Yingru Xu
(Duke University)

Heavy quark transport in heavy-ion collisions and Bayesian estimation of the transport coefficients

At RHIC and the LHC, a deconfined QCD state of matter is created during ultra-relativistic heavy-ion collisions. This strongly-interacting hot and dense matter -- called Quark-Gluon Plasma (QGP)-- exhibits intriguing properties such as near-perfect fluid collectivity and significant jet quenching. Heavy quarks are predominately produced at the beginning of the collisions and their production can be calculated by perturbative QCD due to their large masses. During their propagation in the QGP medium, they lose energy while interacting with the medium. At the end of the evolution, heavy quarks hadronize into heavy flavor hadrons and continue the sequential hadronic interactions. The large mass, the conservation of heavy flavor, and the ability to interpret different momentum region make heavy quark an ideal probe of the QGP medium.
In a transport approach, the interacting strength between heavy quarks and the medium can be characterized by transport coefficients. In this talk, we apply Bayesian inference to estimate the heavy quark transport coefficient. The advantages of such model-to-data comparison are: a systematic and rigorous handling of the experimental and model uncertainties, a complete exploration of the model parameter space, and the possibility to discover novel observables. In addition, we compare two popular but different heavy quark transport approaches, Langevin and linearized Boltzmann equations, to better understand the modeling uncertainties.
 Juan Torres-Rincon
 
May 25, 1h00PM
Friday
(Room C133)

 Marco Catillo (University of Graz, Austria)
On the emergence of particular symmetries in QCD Jacobus Verbaarschot
 
May 15,
1h00PM
Tuesday
(Room C133)

 Vicente Vento
(U. of Valencia, Spain)

The Elusive Glueballs

Abstract: We review results in the physics of glueballs with the aim set on phenomenology. In order to describe glueball properties we resort to a variety of theoretical treatments which include lattice QCD, QCD sum rules, constituent models and AdS/CFT models. We compare the theoretical calculations with the PDG meson summaries to establish glueball candidates. LHCb and future machines will play a crucial role in determining their existence.

 Ismail Zahed
 
May 7,
1h00PM
Monday
(Room C133)
 Stanislaw Glazek
(University of Warsaw, Poland)
Collisions of gluon strings

Abstract: The ridge effect observed in high multiplicity events in proton-proton scattering at LHC can be due to the collisions of flux tubes in the projectiles which are in turn related to the fundamental physics of color confinement. We discuss observable effects due to gluon string collisions in electron-proton and peripheral proton-proton scattering
related to scattering of photons. The final-state multiplicity
and elliptic flow are foreseen to exhibit variation due to
collisions of gluon strings at the level of several percent.
 Ismail Zahed
 
April 5,
4h00PM Thursday (Room C120)

 Ismail Zahed
(Stony Brook U)

Low-x from Strings at EIC
 Juan Torres-Rincon
 Special CFNS Seminar
April 4,
1h00PM
Wednesday
(Room C133)

 Chang-Hwan Lee (Pusan National University, Korea)
Tidal Deformability of Neutron Stars and Gravitational Waves
 Ismail Zahed
 
Mar. 29, 1h00PM
Thursday
(Room C133)
 Yuya Tanizaki (BNL)Exact results on massless 3-flavor QCD and Z3-QCD through new anomaly matching
Abstract: Recently, we find a new 't Hooft anomaly of massless 3-flavor QCD, and it turns out to be useful for constraining the possible chiral symmetry breaking at finite density and zero temperature. We show that massless 3-flavor QCD has an 't Hooft anomaly related to the discrete axial symmetry. We also discuss its consequences on Z(3)-QCD, and especially show that one of the center symmetry, the vector symmetry, or chiral symmetry must always be broken spontaneously.
 Juan Torres-Rincon 
Mar. 26, 2h00PM Monday
(Room C120)

 Ernst Sichtermann (LBNL)g-factors and spin structure

Abstract: Spin, an intrinsic form of angular momentum, plays important roles in nuclear and elementary particle physics.  A number of spin observables have produced surprising results.  In this talk, I will discuss investigations and future opportunities with muon g-2 and the spin structure of the nucleon.

  Special CFNS Seminar
Mar. 9, 11h00AM
Friday
(Room C120)
 Xiangdong Ji
(U. of Maryland)
Theoretical Challenges for EIC Physics Ismail Zahed
 co-organized with CFNS


Mar. 1, 10h30AM
Thursday
(Room D128)
 Yuxiang Zhao
(INFN, Trieste, Italy)

Transverse spin structure study --- from JLab, COMPASS to EIC


Abstract: To understand the spin structure of a nucleon is a fundamental goal of nuclear science. After half a century of investigations, our knowledge of the nucleon spin structure has made impressive progress. However, our current understanding is basically one-dimensional. Meanwhile, the past decade has witnessed tremendous experimental achievements, which led to fascinating new insights into the 3-D structure of the nucleon through semi-inclusive deep inelastic scattering processes (SIDIS). In this talk, I will firstly give a brief introduction on perspectives for the spin structure study to help people to get a feeling on where we are for the one-dimensional picture and why we need to move to 3D studies (TMDs and GPDs). Then I will discuss the achievements and future efforts at JLab (6 GeV and 12 GeV) and COMPASS (CERN) for the TMDs study.  The contributions from a future EIC on the study of TMDs will also be discussed.

 Dmitri Tsybyshev Special CFNS Seminar

Talk broadcast by video conference at Room D128

 Feb. 26, 4h00PM
Monday
 Charlotte Van Hulse
 (U. of Basque Country, Spain)
 Multi-dimensional photographs of the inner nucleon structure

Abstract: Deep-inelastic scattering allows to study the three-dimensional structure of the nucleon in momentum space and in mixed momentum and position space. Various experiments at Jefferson Lab, CERN and DESY have per- formed measurements on semi-inclusive deep-inelastic scattering, providing access to the three-dimensional parton distributions in momentum space, as well as on hard exclusive processes, sensitive to generalized parton distri- butions and thus to the three-dimensional nucleon structure in mixed mo- mentum and position space. An overview of these measurements will be presented and discussed. 
 Dmitri Tsybyshev Special CFNS Seminar
 Feb. 22, 4h00PM
Thursday
 Jan Bernauer
(MIT)
 Proton puzzles at the precision frontier

Abstract: The nucleon and its structure are the focus of intense study on all energy scales, in both current and upcoming experiments. It is one of the simplest systems in non-perturbative QCD and the accurate description of its properties are a touchstone for theoretical calculations.
However, many properties of the proton, for example mass and spin, are still puzzling. Recent precision experiments have highlighted two areas where we do not understand how nature works: the proton radius and the form factor ratio discrepancy. The former, still unsolved, may have opened the door to the discovery of physics beyond the Standard Model. While a solution for the latter seems in reach, the precision results of OLYMPUS prove theoretical calculations to be incomplete.
In this talk, I will discuss the Mainz high precision form factor measurement and global form factor analysis, which are corner stones of the radius puzzle, and the results of the OLYMPUS experiment, set up to study the form factor ratio discrepancy.
I will close with a short description of ongoing and future precision-frontier experiments like MUSE and DarkLight.
 Dmitri Tsybyshev Special CFNS Seminar
 Feb. 21, 1h00PM
 Wednesday
 Enrico Rinaldi
 (BNL)
 What lattice gauge theory can do for Dark Matter searches

Abstract: Lattice simulations of gauge theories are a powerful tool to investigate strongly interacting systems like Quantum ChromoDynamics (QCD). In recent years, the expertise gathered from lattice QCD studies has been used to explore new extensions of the Standard Model of particle physics that include strong dynamics. This change of gear in lattice field theories is related to the growing experimental search for new physics, from accelerator facilities like the Large Hadron Collider (LHC) to dark matter detectors like LUX or ADMX. In my presentation I will explore different plausible scenarios for dark matter physics where strong dynamics play a dominant role and can be tackled by numerical lattice simulations. The importance of lattice field theories is highlighted in the context of dark matter searches, both for direct detection experiments and for collider experiments.
 Christos Kallidonis 
 Feb. 19, 4h00PM
Monday
 Christiano Fanelli
(MIT)
 Exotic physics both within and beyond the Standard Model at GlueX

Abstract: GlueX is a flagship nuclear physics experiment located at Jefferson Lab designed to understand the nature of confinement in QCD by mapping the spectrum of exotic mesons.The experiment utilizes the scattering on nucleon of 9 GeV linearly polarized photons derived from the recently upgraded CEBAF electron beam. The current status of the GlueX detector data collection will be discussed, with a brief overview of the first physics results. Taking advantage of the early data collected GlueX can also do a world’s leading search for BSM physics. In particular a compelling dark-force scenario introduces a new U(1)B gauge symmetry coupling to baryon number. A bump hunt strategy to search for a leptophobic boson has been extended to cover a wide unexplored region where all previous experiments could not set limits. The data collected at GlueX provided a significant contribution to this search. 
 Dmitri Tsybyshev Special CFNS Seminar
 Feb. 12, 1h00PM
Monday
 Mark Mace
(SBU)
 Multiparticle correlations and collectivity in proton nucleus collisions from the initial state

Abstract: In this talk, I will discuss recent progress in understanding multiparticle correlations in small systems from a simple initial state parton model. In this model of eikonal quarks scattering off of a dense nuclear target with localized domains of color charge, we are able to qualitatively reproduce many of the features observed in light-heavy ion collisions at RHIC and the LHC which are often ascribed to collective behavior. These include the ordering of n-th moment two particle Fourier azimuthal anisotropy coefficient, vn{2}; a negative four particle second Fourier cumulant c2{4}, giving rise to a real v2{4}; the similarity for multiparticle second Fourier harmonics $v_2\{4\} \approx v_2\{6\} \approx v_2\{8\}\$; and the energy dependence of the four particle symmetric cumulants. While such patterns are often interpreted as signatures of collectivity arising from hydrodynamic flow, our results provide an alternative description of the multiparticle correlations seen in p+A collisions.
 Christos Kallidonis 
 Feb. 1st. 4h00PM
Thursday
 Ciprian Gal
(University of Virginia
)
 Understating the world with parity violation
Abstract: The unique properties of the electroweak interaction give us the chance to deepen our understanding of the universe. Using parity violating electron scattering we can perform precision tests of the Standard Model or determine unknown nuclear properties. These types of measurements will guide future searches for physics beyond the standard model (BSM) and improve our knowledge of nuclear physics. 
In this seminar I will talk about the most recent result from this line of experiments. Qweak has made the most precise determination of the weak vector charge of the proton to date. The unprecedented precision in determining an electron scattering parity violating asymmetry has been used to extract the weak mixing angle at low energy. This low energy determination constrains possible BSM scenarios on levels comparable with direct searches from the LHC. I will conclude by presenting the exciting opportunities in parity violating electron scattering that will come in the next few years. 
 Dmitri Tsybyshev 
 Jan. 31st, 1h00PM
Wednesday
 Mohamed Anber
(Lewis & Clark College)
 K-strings in pure Yang-Mills theory via supersymmetry

Abstract: Studying k-strings in pure Yang-Mills theory is a difficult task, thanks to the strong coupling nature of the problem. In this talk, I discuss a conjectured continuity between pure Yang-Mills and N=1 super Yang-Mills on R^3XS^1, which enables us to study and relate k-string in both theories. One can show, via reliable semi-classical analysis, that the Polyakov-loop correlation functions depend only on the N-ality of a representation, to the leading order. Further, I discuss W-bosons in super Yang-Mills and show that they are deconfined on the string worldsheet, and therefore, can change neither the string N-ality nor its tension. This phenomenon mirrors the fact that soft gluons do not screen probe charges with non-zero N-ality in pure Yang-Mills. I also comment on the scaling law of k-strings in super Yang-Mills and compare our findings with strings in Seiberg-Witten theory and holographic studies that were performed in the 't Hooft large-N limit.
 Edward Shuryak 
 Jan. 25, 4h00PM
Thursday
Ronald Belmont
(University of Colorado, Boulder) 
 Searching for collectivity and testing the limits of hydrodynamics: small systems at RHIC

Abstract: The standard picture of heavy ion collisions is that large systems (collisions of large nuclei like Au+Au and Pb+Pb) create a quark-gluon plasma that exhibits collective behavior indicative of nearly inviscid hydrodynamical evolution. Recently, data from small systems (collisions of a small projectile and a large target like d+Au and p+Pb) have been found to exhibit strikingly similar evidence for collective behavior. To further elucidate these results, RHIC has delivered a small system geometry scan of p+Au, d+Au, and 3He+Au collisions at 200 GeV between as well as a beam energy scan of d+Au collisions at 4 different energies: 200, 62.4, 39, and 19.6 GeV.  In this talk we present results from the small systems scans at RHIC and discuss the implications for collectivity and the applicability of hydrodynamics.
 Dmitri Tsybyshev 
 Jan. 22, 4h00PM
Monday
 Salvatore Fazio (BNL) An uncharted territory - imaging the the building blocks of the visible matter in multi-dimensions

Abstract: Understanding the emergence of the nucleons from their constituents, the quarks and the gluons is a key challenge for modern science. During the past decade, there have been tremendous efforts towards going beyond the one-dimensional structure of the proton to a three-dimensional tomographic imaging of the proton’s constituents. This can shed light on the properties of these building blocks of the Universe, described by the theory of quantum chromo-dynamics (QCD). It also provides essential information to understand how the strong interaction keeps them confined in the fundamental particles. The 3-D structure of the proton in coordinate and momentum space can be described respectively via the Generalized Parton Distributions (GPDs) and the Transverse Momentum Dependent (TMD) parton distribution functions. With advancements in theory and the development of phenomenological tools we are preparing for the next step in subnuclear tomographic imaging. The 2015 nuclear physics long-range plan endorsed the realization of a high-luminosity polarized Electron-Ion Collider (EIC) as the next large construction project in the United States. This will open a unique opportunity for very high precision measurements.

In this seminar I shall narrate my personal research experience in pursuing the multi- dimensional knowledge of the proton’s structure and its spin. I will start with my investigation of GPDs at the ZEUS experiment at HERA, the previous and only electron+proton collider, through measurements of the exclusive production of a real photon – a process known as Deeply Virtual Compton Scattering. I will also tell how we are now accessing the Sivers TMD function in polarized proton+proton collisions at RHIC through the measurement of transverse single spin asymmetries in Drell-Yan and weak boson production. This is an effective path to test the fundamental QCD prediction of the non-universality of the Sivers function. Finally, I shall give a brief description of the EIC project, highlight several key high precision measurements from its planned broad physics program and discuss the expected impact on our current understanding of the 3-D structure of nucleons and nuclei and on how the nuclear environment modifies the parton distributions.


 Dmitri Tsybyshev 
 Jan. 18, 4h00PM
Thursday
 Kiminad Mamo
(SBU)
 The Coulomb Branch of N=4 SYM and Its Gravity dual as a New Holographic Model to QCD

Abstract: We discuss various aspects of N = 4 super Yang-Mills theory on the Coulomb branch (cSYM) and its string theory dual. After showing that N = 4 cSYM has most of the properties expected from pure Yang-Mills theory at strong coupling, such as confinement (with Cornell potential), mass gap (with quantized mass spectrum), and an equation state similar to pure Yang-Mills theory on the lattice, we will discuss the hydrodynamic transport coefficients, and hard probe parameters (such as drag coefficient and jet quenching parameter) of N = 4 cSYM plasma. In addition, a new holographic mechanism for hadronization or particle production from the QGP will be proposed, and shown to be equivalent to the well-known Cooper-Frye formula in the hydrodynamic or low frequency limit. Finally, we add flavor to N = 4 cSYM by using coincident N_f D9-anti D9 branes, and realize chiral symmetry breaking through open string tachyon condensation.
 Christos Kallidonis 
 Jan. 31, 1h00PM
Wednesday
 Mohamed M. Anber
(Lewis & Clark College)
K-strings in pure Yang-Mills theory via supersymmetry

Abstract: Studying k-strings in pure Yang-Mills theory is a difficult task, thanks to the strong coupling nature of the problem. In this talk, I discuss a conjectured continuity between pure Yang-Mills and N=1 super Yang-Mills on R^3XS^1, which enables us to study and relate k-string in both theories. One can show, via reliable semi-classical analysis, that the Polyakov-loop correlation functions depend only on the N-ality of a representation, to the leading order. Further, I discuss W-bosons in super Yang-Mills and show that they are deconfined on the string worldsheet, and therefore, can change neither the string N-ality nor its tension. This phenomenon mirrors the fact that soft gluons do not screen probe charges with non-zero N-ality in pure Yang-Mills. I also comment on the scaling law of k-strings in super Yang-Mills and compare our findings with strings in Seiberg-Witten theory and holographic studies that were performed in the 't Hooft large-N limit. 
 Eduard Shuryak 
 Jan. 11, 4h00PM
Thursday
 Christos Kalidonis (SBU) Computing the nucleon spin from Lattice QCD

Abstract: The distribution of the proton spin amongst its constituent quarks and gluons is considered as one of the fundamental problems of physics, and a rich experimental and theoretical activity is on-going, in the effort to resolve this long-standing puzzle. Nowadays, Lattice QCD is in a good position to provide reliable predictions and answers to fundamental problems, from first principles calculations. In this talk, we elaborate on the novel methodology employed in a recent Lattice QCD calculation with physical values of the parameters, in which the various quark and gluon contributions to the proton spin are determined to satisfactory accuracy. The calculation includes for the first time all contributions from sea quarks, which are notoriously difficult to obtain on the lattice. We show our final results of the quark and gluon contributions to the nucleon spin, with each contribution determined separately. We find very good agreement with the value 1/2 of the nucleon total angular momentum, thus resolving the long standing “proton spin puzzle".

  
 Nov 29, 1h00PM
 Wednesday
 A. Gorsky (IITP, Moscow) Tunneling in quantum mechanics and N=2 SUSY Yang-Mills theory

Abstract: We discuss  the Nekrasov partition function in $\mathcal{N}=2$ supersymmetric Yang-Mills (SYM) gauge theory in the particular limit when one of the parameters of the $\Omega$-deformation is large and focus at the near-naive pole regions
of the twisted superpotential. In the strict Nekrasov-Shatashvili limit in $SU(2)$ case we explain 
at the gauge theory side the origin of the  
exponentially small gaps well above barrier in the spectrum of corresponding quantum mechanical(QM) problem. We show explicitly that the local 
2d $\mathcal{N}=(2,2)$ models near the naive poles for $SU(2)$ case are the $\mathbb{C}P^1$ models with pole dependent
values of K\"ahler parameters. The corresponding analysis for $SU(N)$ case is performed. Upon the proper 
resummation of the instanton transseries  the poles become cuts
enclosed with the curves of marginal stability  around each cut. When the small second
parameter of deformation is switched on the near-pole the twisted potential  is identified with the 
vortex partition function in the sigma model. 
The interpretation of the non-perturbative  phenomena in the classical Liouville 
conformal blocks is suggested and we argue that 
the classical conformal blocks enjoy the wall-crossing phenomena nearby the naive poles. We argue using the 
$AdS_3/CFT_2$ holography  that upon the proper resummation of the non-leading terms 
the naive poles in the indermediate masses in the scattering  of two heavy states in $AdS_3$ gravity
get transformed into the cuts surrounding with CMS. 
Some comments concerning the possible interpretation of the gap in QM 
in terms of the Schwinger monopole-pair production in 4d are presented.
 D. Kharzeev 
 Nov 7, 1h00PM
 Tuesday
 Adith Ramamurti Role of QCD Monopoles in Jet Quenching

Abstract: QCD monopoles are magnetically charged quasiparticles whose Bose-Einstein condensation (BEC) at T<T_c creates electric confinement and flux tubes.  The ``magnetic scenario" of QCD proposes that scattering on the non-condensed component of the monopole ensemble at T>T_c is responsible for the unusual kinetic properties of QGP. In this talk, I will go over recent progress in this magnetic scenario, and focus on a calculation of the contribution of the monopoles to jet quenching phenomenon, using the BDMPS framework and  hydrodynamic backgrounds. In the lowest order for cross sections, we calculate the nuclear modification factor, R_AA, and azimuthal anisotropy, v_2, of jets, as well as the dijet asymmetry, A_j, and compare those to the available data. We find relatively good agreement with experiment when using realistic hydrodynamic backgrounds. In addition, we find that event-by-event fluctuations are not necessary to reproduce R_AA and v_2 data, but play a role in A_j. Since the monopole-induced effects are maximal at T~T_c, we predict that their role should be significantly larger, relative to quarks and gluons, at lower RHIC energies.

 C. Kallidonis 
 Nov 6, 1h00PM
 Monday 
 Pak Hang Chris Lau
 (MIT)
 Baryon constraint in Sakai-Sugimoto model

Abstract: Sakai-Sugimoto model is a top-down holographic qcd model. Baryons are described by instanton solutions in the model. The model has many successes such as the reproduction of chiral anomaly, computation of properties of baryons etc.. However, Hata and Murata pointed out and showed that one important baryon constraint which is responsible for selecting the correct 3-flavour baryon multiplets cannot be derived from the model. In the talk, I will present our proposed solution and show how it can help recover the required constraint while preserving the other features in the hqcd model.
 Ismail Zahed 
 Nov 1, 11h45AM
 Wednesday
 James Lattimer
 (Stony Brook)
 Constraints on Nucleosynthesis and Neutron Star Structure from the Neutron Star Merger GW170817

Abstract: The recent discovery of a neutron star merger GW170817 by LIGO/VIRGO dramatically confirms the hypothesis that the origin of heavy r-process elements is decompressing neutron star matter tidally and shock ejected from mergers of compact binaries containing neutron stars.  Initially considered speculative, and long contraindicated by observations and prevailing theories of galactic chemical evolution, this idea, which was proposed over 40 years ago, was revitalized in the last few years by the detection of Pu-244 in ocean sediments, the observation of r-process elements in stars in only one of ten ultra-faint dwarf galaxies, hints that some short gamma-ray bursts have infrared afterglows, the continued failure of supernova models to eject sufficient neutron-rich matter, and a revolution in our understanding of galaxy formation.  The predicted early blue (optical) and late red (infrared) emission observed from the visible counterpart of GW170817 essentially confirms r-process nucleosynthesis in the ejecta in quantities sufficient to explain observed abundances. Moreover, coincident gamma-ray observations confirms the identification of mergers as a source of short gamma-ray bursts.  In addition, the estimated masses of the inspiralling neutron stars, together with observations of significant mass ejection, establishes much better limits to the neutron star maximum mass (2.2 M_sun < M_max < 2.5 M_sun) then heretofore available.  It has also been suggested that consistency with hydrodynamical models requires the radii of typical 1.5 M_sun neutron stars to be larger than about 10.6 km and the upper limit to tidal polarizability from the gravitational wave observation indicates radii smaller than 13.5 km, in line with neutron matter theoretical predictions.
 Edward Shuryak 
 (Postponed, new date will be posted)  Mark Mace
 (Stony Brook)
 Multiparticle correlations and collectivity in proton nucleus collisions from the initial state

Abstract: In this talk, I will discuss recent progress in understanding multiparticle correlations in small systems from a simple initial state parton model. In this model of eikonal quarks scattering off of a dense nuclear target with localized domains of color charge, we are able to qualitatively reproduce many of the features observed in light-heavy ion collisions at RHIC and the LHC which are often ascribed to collective behavior. These include the ordering of n-th moment two particle Fourier azimuthal anisotropy coefficient, vn{2}; a negative four particle second Fourier cumulant c2{4}, giving rise to a real v2{4}; the similarity for multiparticle second Fourier harmonics $v_2\{4\} \approx v_2\{6\} \approx v_2\{8\}\$; and the energy dependence of the four particle symmetric cumulants. While such patterns are often interpreted as signatures of collectivity arising from hydrodynamic flow, our results provide an alternative description of the multiparticle correlations seen in p+A collisions.

 
Christos Kallidonis
 
 Oct 18th, 4h00PM
 Wednesday
 Yuta Kikuchi
 (Stony Brook 

 Global inconsistency, 't~Hooft anomaly, and level crossing in quantum mechanics
Abstract: An 't Hooft anomaly is the obstruction for gauging symmetries, and it constrains possible low-energy behaviors of quantum field theories by excluding trivial infrared theories. 
Global inconsistency condition is recently proposed as a milder condition but is expected to play an almost same role by comparing high symmetry points in the theory space. 
In order to clarify the consequence coming from this new condition, we discuss several quantum mechanical models with topological angles and explicitly compute their energy spectra.
 Christos Kallidonis  
 Oct 17th, 1h00PM
 Tuesday
 Prof. Holger Bech Nielsen
 Niels Bohr Institute
 The 3.5 keV X-ray radiation from our Dark Matter Pearls Christos Kallidonis 
 Oct 16th, 1h00PM
 Monday
 Zohar Komargodski
 (Simons Center, Stony Brook)
 Dynamics of Quantum Chromodynamics in 3+1 and 2+1 Dimensions

Abstract: We review recent developments concerning the dynamics of Yang-Mills theory and QCD in 3+1 dimensions. In particular, we discuss the consequences of time-reversal symmetry breaking, and show that this allows to make contact between the dynamics of four-dimensional theories and three-dimensional theories. We describe new discrete anomalies in these systems and prove various general theorems about the possible ground states of Yang-Mills theory in 3+1 and 2+1 dimensions. We present conjectures about new phases of 2+1 dimensional QCD and Adjoint QCD.
 Edward Shuryak 
 Oct 5th, 4h00PM
 Thursday
 Derek Teany
 (Stony Brook)
 Transits of the QCD Critical Point Christos Kallidonis 
 Oct 4th, 1h00PM
 Wednesday
 Vlad Pantuev Jet quenching and corona effect
See this paper.
 Edward Shuryak 
 Oct 3rd, 1h00PM
 Tuesday
 Yizhuang Liu
 (Stony Brook)
 Rotating Dirac Fermions in a magnetic field in 1+2, 3 dimensions  Ismail Zahed 
 Sep 28th, 4h00PM
 Thursday
 Yizhuang Liu
 (Stony Brook)
 Heavy baryons and their exotics from instantons in Holography  Christos Kallidonis  



Past Seminars
Time Speaker Title Host
August 24, 3h30PM
Thursday
Stanislaw Glazek
(University of Warsaw & Yale University)
Quark-antiquark Hamiltonian in one-flavor QCD with a gluon-mass ansatz
As a new tool for describing hadrons in the Minkowski space-time, the renormalization group procedure for effective particles (RGPEP) is applied to heavy quarkonium problem in one-flavor QCD [1]. A degree of universality is obtained for the binding quark-antiquark interaction in the weak-coupling approximation, assuming that beyond perturbation theory gluons obtain effective mass: the Coulomb potential with Breit-Fermi spin couplings is corrected by a spin-independent harmonic oscillator term that does not depend on the assumed effective gluon mass or the choice of the RGPEP generator. The concept of generator will be explained by comparison with Wilsonian renormalization group procedure. The new tool is applicable in studies of the effective gluon dynamics beyond the leading weak-coupling approximation or entirely beyond the perturbative expansion.
[1] S.D.Glazek, M.Gómez-Rocha,J .More, K.Serafin, arXiv:1705.07629 [hep-ph]
Ismail Zahed
August 1, 1PM
Tuesday
Rasmus Larsen
(Stony Brook)
Convergent perturbation theory in quantum mechanics

I will try to give some simple examples for why perturbation theory leads to oscillating factorial growing contributions. We will see that in the 1d integral this can be fixed by an integral cutoff. For 1d quantum mechanics the cutoff is effectively done by introducing an effective mass. With this, I will show how we can obtain the ground state energy of 1d quantum mechanics for the x^4 potential. In the x^4 case, the effective mass leads to an expansion in factors of m and g^(1/4). By minimizing the highest order contribution, we find that the ground state energy is proportional to g^(1/3) as it should be.

July 27, 3h30PM
Thursday
Sayantan Sharma
(BNL)
Insights on microscopic degrees of freedom of phases of QCD from Lattice

There has been a lot of progress in recent years on measuring the bulk thermodynamic properties of QCD from Lattice. However Lattice studies can now give us new insights on even the microscopic degrees of freedom in different phases of QCD. I will discuss some instances like the studies of fluctuations, screening masses and the eigenvalue spectrum of the Dirac operator.
J.-F. Paquet
July 18, 1PM
Tuesday
Roy Lacey
(Stony Brook)




July 10, 3PM
Monday
Rasmus Larsen
(Stony Brook)
PhD Defence



June 1, 3h30PM
Thursday
Ismail Zahed
(Stony Brook/BNL)
Holographic string, saturation, entropy and black holes at collider energies



May 25, 3h30PM
Thursday
Dima Kharzeev
(Stony Brook/BNL)
Probing quantum entanglement at the Electron Ion Collider



May 4, 3h30PM
Thursday
Roy Lacey
(Stony Brook)
Charge separation measurements in p+Au and Au+Au collisions at RHIC; Implications for the search for the chiral magnetic effect



May 1, 12h45
Monday
Peng Huo
(Stony Brook)
Measurement of longitudinal flow correlations in Pb+Pb collisions at √sNN =2.76 and 5.02 TeV with the ATLAS detector



April 24, 1PM
Monday
Prithwish Tribedy
(BNL)
Search for the Chiral Magnetic Effect at RHIC : challenges and opportunities

In this talk I will discuss about the ongoing and future efforts at RHIC towards the search for the Chiral Magnetic Effect (CME). I will focus on the recent STAR measurements of the charge separation across the reaction plane, a predicted signal of the Chiral Magnetic Effect. Although charge separation has been observed, it has been argued that the measured separation in A+A collisions can be explained by elliptic flow related backgrounds. I will discuss on the challenges in disentangling such background contributions from the signals of CME. I will also discuss on implications of the recent measurements of charge separation in p+A collisions towards the search for CME.
J.-F. Paquet
April 20, 3h30PM
Thursday
Andrey Sadofyev
(MIT)
Chiral Vortical Effect for Bosons

The thermal contribution to the chiral vortical effect is believed to be related to the axial anomaly in external gravitational fields. We use the universality of the spin-gravity interaction to extend this idea to a wider set of phenomena. We consider the Kubo formula at weak coupling for the spin current of a vector field and derive a novel anomalous effect caused by the medium rotation: the chiral vortical effect for bosons. The effect consists in a spin current of vector bosons along the angular velocity of the medium. We argue that it has the same anomalous nature as in the fermionic case and show that this effect provides a mechanism for helicity transfer, from flow helicity to magnetic helicity.
Dima Kharzeev
April 10, 1PM
Monday
Laura Tolos
(Institut de Ciencies de l’Espai)
Charm and Beauty @ Extremes

We study the behavior of excited charmed and beauty baryonic states within a unitarized coupled-channel theory in matter that fulfills heavy-quark spin symmetry constraints. We analyze the implications for the formation of charmed mesic nuclei and the propagation of charmed and beauty hadrons in heavy-ion collisions from RHIC to FAIR energies.
J.-F. Paquet
April 6, 3h30PM
Thursday
Yuta Kikuchi
(Stony Brook)
Topological Properties of the Chiral Magnetic Effect in Multi-Weyl Semimetals

I will discuss the chiral magnetic effect (CME) in multi-Weyl semimetals (multi-WSMs) based on the chiral kinetic theory. Multi-WSMs are WSMs with multiple monopole charges that have nonlinear and anisotropic dispersion relations near Weyl points, and we need to extend conventional computation of CME in WSMs with linear dispersion relations. Topological properties of CME in multi-WSMs are investigated in details for not only static magnetic fields but also time-dependent (dynamic) ones. We propose an experimental setup to measure the multiple monopole charge via the topological nature hidden in the dynamic CME.

April 4, 2h30PM
Tuesday

Kong Tu
(Rice University)
New insights to the search for the anomalous chiral effects using small colliding system at the LHC

In relativistic heavy ion collisions, anomalous chiral effects have been predicted to occur in presence of a strong magnetic field induced by the spectator protons, e.g., the chiral magnetic effect (CME) and chiral magnetic wave (CMW). In the past decade, measurements of CME and CMW have been attempted from RHIC to the LHC energies, where significant signals were found to be in line with expectations of the chiral effects. However, soon after the initial excitement, various sources of background effects were identified and proposed to qualitatively describe the data. The origin of the backgrounds has been extensively studied, but still remains inconclusive to date. Recently, novel collective phenomenon has been found in high-multiplicity pA collisions, similar to those in AA collisions. Due to the weak correlation between the magnetic field direction and the event plane, the high-multiplicity pPb data are expected to have much suppressed CME and CMW signal, comparing to that in PbPb collisions, and thus provide an ideal testing ground to observables related to the anomalous chiral effects. In this talk, I will present new measurements related to the CME and CMW from CMS in pPb and PbPb collisions at the LHC, and discuss their implications to the search for the anomalous chiral effects including an outlook for future studies.

April 3, 12h45
Monday
Mingliang Zhou
(Stony Brook)
New results related to QGP-like effects in small systems with ATLAS

Quark Gluon Plasma (QGP), a new state of matter existing at high temperatures formed in relativistic heavy ion collisions, has been studied in measurements of various observables in Pb+Pb collisions at LHC. Recently, similar QGP-like effects have also been observed in small systems like $pp$ and $p+$Pb, by measuring two-particle long-range azimuthal correlation. In order to access the collective nature of multi-particle production, the correlation measurements are extended using multi-particle cumulants, which have confirmed the collective behavior in $p+$Pb. However in $pp$, cumulants do not yet provide clear evidence for collectivity due to large residual dijet contribution. In order to address this, a new subevent cumulant method is applied, and it provides an evidence for collectivity in $pp$ collisions.

March 23, 1PM
Thursday
Carlos Naya
(Durham University)
A solitonic approach to neutron stars: The (BPS) Skyrme model

The Skyrme model is a low energy effective field theory of strong interactions where nuclei and baryons appear as collective excitations of pionic degrees of freedom. Proposed by Tony Skyrme in the sixties, his ideas received further support when it was discovered that in the limit of the large number of colours of QCD, an effective theory of mesons arises. In the last years, there has been a revival of Skyrme's ideas and new related models, some of them with BPS bounds (topological lower energy bounds), have been proposed. It is the aim of this talk to focus on the one known as BPS Skyrme model. After a brief introduction to this BPS limit we study its application to neutron stars where we will find that high maximal masses are supported. In addition, the BPS Skyrme model allow us to perform both mean-field and exact calculations and a comparison between both approaches will be presented.
J.-F. Paquet
March 13, 1PM
Monday
Ismail Zahed
(Stony Brook University)
Sachdev-Yee-Kitaev and equilibration


March 9, 3h30PM
Thursday
Mareike Haberichter
(University of Massachusetts - Amherst)
Nuclear Matter EoS and thermodynamic Properties of Skyrme models

The Skyrme model is a candidate to describe the low energy regime of QCD where baryons and nuclei are topological excitations in a low-energy effective field theory of pions. The Skyrme model and its BPS variant (Skyrme model with a lower topological energy bound which is saturated) have been applied to the description of nuclei with notable recent success, e.g. quantitative description of Carbon-12 (including the Holye state and its rotational band) and of the low-lying energy spectrum of Oxygen-16. In this talk, we test Skyrme theories as models for nuclear matter at high densities and explore the thermodynamical properties of skyrmionic matter at zero temperature. We compute analytically the mean-field equation of state in the high and medium pressure regimes by applying topological bounds on compact domains. We identify which term in a generalised Skyrme model is responsible for which part in the equation of state and compare our findings with the corresponding results in the Walecka model. We find that the BPS submodel plays the dominant role at large densities. The BPS Skyrme model even allows us to derive thermodynamical variables and densities directly from the theory without having to perform a mean-field limit. This distinguishes the BPS Skyrme model from other models of nuclear matter where usually a mean-field limit has to be performed.
J.-F. Paquet
March 8, 4PM
Wednesday
Yachao Qian
(Stony Brook University)
PhD Defence


March 2, 3h30PM
Thursday
Sergey Syritsyn
(Stony Brook/BNL)
Lattice Calculation 
of Nucleon Electric Dipole Moments

Searches for permanent electric dipole moments (EDM) of neutrons, protons, and nuclei are the most sensitive probes for CP violation, which is necessary for baryogenesis. Currently developed experiments will improve bounds on the neutron EDM by 2-3 orders of magnitude. However, to put constraints on CP-violating interactions, nonperturbative QCD calculations of nucleon structure are necessary. I will present some recent developments in lattice calculations of nucleon EDMs induced by quark-gluon CP-odd interaction.

February 27, 1PM
Monday
Masaru Hongo
(RIKEN)
Path-integral formula for local thermal equilibrium

Relativistic hydrodynamics is formulated based on the assumption that systems are almost in local thermal equilibrium. However, a quantum field theoretical way to handle such a locally thermalized system has not been clearly clarified. In this study, we develop a complete path-integral formulation of relativistic quantum fields in local thermal equilibrium, which brings about the emergence of thermally induced curved spacetime. The obtained path-integral formula for local thermal equilibrium enables us to derive nondissipative part of hydrodynamic constitutive relations based on symmetry arguments. As one application, we discuss a field theoretical derivation of anomalous hydrodynamics which captures the chiral magnetic/vortical effect.
Yuta Kikuchi
February 23, 3h30PM
Thursday
Chun Shen
(Brookhaven National Lab)
A hybrid approach to relativistic heavy-ion collisions at the RHIC BES energies

Using a hybrid (viscous hydrodynamics + hadronic cascade) framework, we model event-by-event bulk dynamics of relativistic heavy-ion collisions at the Relativistic Heavy Ion Collider (RHIC) Beam Energy Scan (BES) collision energies, including the effects from non-zero net baryon current and its dissipative diffusion during the evolution. This framework is in full (3+1)D, which allows us to study the non-trivial longitudinal structure and dynamics of the collision systems, for example the baryon stopping and transport, as well as longitudinal fluctuations. We study hadronic chemistry, identified particle spectra and anisotropic flow over the energy range relevant to the RHIC BES. We investigate the effects of net-baryon current/diffusion and pre-equilibrium dynamics on hadronic observables.
J.-F. Paquet
February 20, 1PM
Monday
Yuta Kikuchi
(Stony Brook)
Chiral magnetic effect without chirality source in asymmetric Weyl semimetals

We describe a new type of the Chiral Magnetic Effect (CME) in Weyl semimetals with an asymmetry in the dispersion relations of the left- and right-handed chiral Weyl cones. In such materials, time-dependent pumping of electrons from a non-chiral source generates a non-vanishing chiral chemical potential. This is due to the different capacities of the left- and right-handed (LH and RH) chiral Weyl cones arising from the difference in the density of states in the LH and RH cones. The chiral chemical potential then generates, via the chiral anomaly, a current along the direction of an applied magnetic field even in the absence of an external electric field. We illustrate the effect by an effective field theory argument as well as by the chiral kinetic theory calculation for a Weyl semimetal with different Fermi velocities in the left and right chiral Weyl cones.

February 16, 2h30PM
Thursday
Juergen Eser
(Goethe University Frankfurt)
The extended linear sigma model within the functional renormalization group approach

We use the functional renormalization group (FRG) technique to explore the characteristics of the so-called extended linear sigma model (eLSM). This model is an effective description of the strong interaction in terms of quarks and mesonic fields. Besides scalars and pseudoscalars, it also features vector and axial-vector mesons. The first part focuses on the restoration of chiral symmetry in the context of the transition from hadronic matter to the quark-gluon plasma in the phase diagram of quantum chromodynamics (QCD). Results on the order of the chiral phase transition in the presence of vector and axial-vector mesons will be presented. Vector mesons are of particular interest since modifications related to chiral symmetry restoration affect their in-medium spectral properties, which can be detected via decays into dileptons. Effects of the axial anomaly and the explicit breaking of chiral symmetry due to nonzero quark masses are also studied. The mass degeneracy of chiral partners beyond the phase boundary and the phase diagram as a function of the temperature and the quark-chemical potential will be shown.
The second part sheds light on the low-energy limit of the eLSM. We consider the influence of wave-function renormalization factors and couplings beyond the local potential approximation. The infrared-relevant couplings can be associated with the corresponding low-energy constants of QCD.
J.-F. Paquet
February 3, 12PM
Friday
Adith Ramamurti
(Stony Brook University)
Practice talk: Path-Integral Monte Carlo Study of the Magnetic Component of Quark-Gluon Plasma At and Above $T_c$


February 3, 12h40PM
Friday
Aleksas Mazeliauskas
(Stony Brook University)
Practice talk: Initial conditions for hydrodynamics from weakly coupled pre-equilibrium evolution


February 2, 3h30PM
Thursday
Jean-François Paquet
(Stony Brook University)
Practice talk: Electromagnetic probes in A+A and p+A collisions


February 2, 1PM
Thursday
Huiyoung Ryu
(Pusan National University)
Photoproduction and transition form factor

Ismail Zahed
January 26, 3h30PM
Thursday
Björn Schenke
(Brookhaven National Lab)
The Ridge in p+p and p+Pb collisions: Yang-Mills+Lund fragmentation

We present calculations of azimuthal anisotropies of produced gluons in p+p and p+Pb collisions within the Yang-Mills framework. In order to compare to recent experimental data from the LHC we combine the Yang-Mills calculation with the Lund fragmentation framework from PYTHIA, resulting in a new event generator that includes particle production from the color glass condensate with string fragmentation. We present results of mean transverse momentum and anisotropic flow for identified particles, showing a clear mass dependence, similar to that observed in the experimental data.
J.-F. Paquet
January 26, 9h30AM
Thursday
Aleksas Mazeliauskas
(Stony Brook University)
PhD Defence: Fluctuactions in ultrarelativistic heavy ion collisions
January 18, 1PM
Wednesday
Peter Petreczky
(Brookhaven National Laboratory)
Weakly coupled QGP? J.-F. Paquet
December 21, 3PM
Wednesday
Mauricio Adrian Escobar-Ruiz
(Universidad Nacional Autónoma de México & University of Minnesota)
Discussion on recent developments in semi-classical theories Edward Shuryak
December 21, 1PM
Wednesday
Alezander Turbiner
(Universidad Nacional Autónoma de México & Stony Brook)
Developments in semi-classical theories Edward Shuryak
December 8, 3h30PM
Thursday
Michał P. Heller
(Perimeter)
Hydrodynamization and transient modes of expanding plasma in kinetic theory J.-F. Paquet
December 1, 3h30PM
Thursday
Stefan Flörchinger
(Heidelberg University)
Dissipation from the analytically continued 1 PI effective action

The analytic continuation from the Euclidean domain to real space of the one-particle irreducible quantum effective action is discussed in the context of generalized local equilibrium states. Discontinuous terms associated with dissipative behavior are parametrized in terms of a conveniently defined sign operator. A generalized variational principle is then formulated, which allows to obtain causal and real dissipative equations of motion from the analytically continued quantum effective action. Differential equations derived from the implications of general covariance determine the space-time evolution of the temperature and fluid velocity fields and allow for a discussion of entropy production including a local form of the second law of thermodynamics.
Aleksas Mazeliauskas
November 28, 1PM
Monday
Morgan Henry Lynch
(University of Wisconsin - Milwaukee)
Applications of Accelerated Quantum Dynamics to Hadronic Physics

Utilizing the Unruh effect, and the associated temperature, I will present an effective Fermi theory of acceleration-induced interactions. This accelerated quantum dynamics provides a framework for computing a wide class of observables to probe the physics of high acceleration. General expressions for the emission rate, multiplicity, power, spectra, and displacement law of particles undergoing time-dependent acceleration and transitioning into a final state of arbitrary particle number will be presented. As potential applications, I will show how this formalism may be applied to thermal particle production in hadronic collisions and quark gluon plasmas.

November 18, 12h45PM
Friday
Alina Czajka
(McGill University)
Quantum-field-theoretical approach to shear and bulk relaxation times

The shear and the bulk relaxation times are important ingredients of the second order hydrodynamics whose success in heavy ion phenomenology is unquestioned. Unlike viscosites themselves, field theoretical calculations of the relaxation times are hard to come by in literature, especially for the bulk relaxation time. In this talk, we report two field-theoretical analyses involving the shear and the bulk relaxation time. First, by carefully examining the analytic structure of the stress-energy tensor response functions, we have been able to derive, for the first time, a Kubo formula involving both the shear and the bulk relaxation times. Second, by evaluating the Kubo formula within the massless scalar theory, we have so far been able to calculate the shear relaxation time in a simple form. We will then show how this calculation can be extended to calculate the bulk relaxation time as well.
J.-F. Paquet
November 10, 2h30PM
Thursday
Raju Venugopalan
(Brookhaven National Lab)
Berry's phase and the Chiral Anomaly from supersymmetric world lines: towards the anomalous Boedeker theory

We outline an ab initio derivation of how Berry's phase and the chiral anomaly arise in a heat kernel regularization of the fermion determinant in QCD. We further argue that a semi-classical treatment of the resulting supersymmetric world line equations of motion provides the framework to derive a chiral kinetic theory that includes the effects of fluctuations induced by topological transitions. The phenomenological implications of these developments for the Chiral Magnetic Effect are noted.
Dima Kharzeev
November 9, 1PM
Wednesday
Yi Yin
(MIT)
New quantum effects in relativistic magnetohydrodynamics: topology, instability and self-similarity

Chiral anomaly induces a family of macroscopic quantum behaviors in chiral medium, including the chiral magnetic effect. The application of these effects covers systems of enormous varieties and scales, ranging from the structure of primordial magnetic field in the early universe to charged particle correlation in heavy-ion collisions and negative magnetoresistivity in the newly discovered Weyl semimetal. In this talk, I will present three closely related aspects of new quantum effects present in fluids that contain chiral fermions: topology, instability and self-similarity. I will demonstrate the magnetic reconnections changing chirality of magnetic flux induces in the fluid a quantized electric current, a new kind of the "chiral magnetic effect". I further show self-similar inverse cascade driven by the chiral magnetic current. Finally, I report a new type of instability in a magnetohydrodynamics due to anomaly.

November 2, 12h30PM
Wednesday
Yachao Qian
(Stony Brook)
Form Invariance, Topological Fluctuations and Mass Gap of Yang-Mills Theory

We study the quantum Yang-Mills theory in the presence of topologically nontrivial backgrounds. The topologically stable gauge fields are constrained by the form invariance condition and the topological properties. Obeying these constraints, the known classical solutions to the Yang-Mills equation in the 3- and 4-dimensional Euclidean spaces are recovered, and the other allowed configurations form the nontrivial topological fluctuations at quantum level. Together, they constitute the background configurations, upon which the quantum Yang-Mills theory can be constructed. We demonstrate that the theory mimics the Higgs mechanism in a certain limit and develops a mass gap at semi-classical level on a flat space with finite size or on a sphere.
Ismail Zahed
October 27, 4PM
Thursday
Eugene Levin
(Tel Aviv University)
Perturbative QCD and beyond: Bose-Einstein correlation and $v_n$ at any n
Dima Kharzeev
October 21, 12h45PM
Friday
Niklas Mueller
(Heidelberg University)
Chiral magnetic effect and anomalous transport from real-time lattice simulations

We present a first-principles study of anomaly induced transport phenomena by performing real-time lattice simulations with dynamical fermions coupled simultaneously to non-Abelian SU(Nc) and Abelian U(1) gauge fields. Investigating the behavior of vector and axial currents during a sphaleron transition in the presence of an external magnetic field, we demonstrate how the interplay of the chiral magnetic and chiral separation effect leads to the formation of a propagating wave. We further analyze the dependence of the magnitude of the induced vector current and the propagation of the wave on the amount of explicit chiral symmetry breaking due to finite quark masses. Further we perform simulations using overlap-fermions for the first time in real-time, showing that in the classical statistical regime they can be related to the Wilson formulation.
J.-F. Paquet
October 6, 3h30PM
Thursday
Yuya Tanizaki
(Brookhaven National Lab)
Lefschetz-thimble path integral for studying the Silver Blaze phenomenon

Recently, Picard-Lefschetz theory has received much attention in the context of the sign problem, because it enables us to study the system with the complex classical action nonperturbatively by extending the semiclassical analysis. In this seminar, after a brief introduction, I will apply it to the one-site Hubbard model. This model has a severe sign problem, which looks quite similar to that of the finite-density QCD at low temperatures. By solving this model using the Lefschetz-thimble path integral, we are trying to understand the structure of the sign problem of finite-density QCD. In particular, I give a speculation about the early-onset problem of the baryon number density, called the baryon Silver Blaze problem. We also discuss that the complex Langevin method does not work in a certain situation.
J.-F. Paquet
August 29, 2h30PM
Monday
Niko Jokela
(University of Helsinki)
Towards sliding stripes in holography

The D3-D7' system provides a unique laboratory to address notoriously difficult questions in (2+1)-dimensional fermionic systems at strong coupling via AdS/CFT. I will review select properties of the dense holographic matter in this brane intersection model. At low temperature, the ground state is a spatially modulated charge and spin density wave. A linear external electric field will kick the stripes to slide. Holographic techniques allows us to separate out the contributions of the modulation and the sliding to the electric conductivities. This provides a new viewpoint to understand the otherwise challenging quantum Hall fluids which spontaneously break the translational symmetry.
René Meyer
August 8, 1PM
Monday
Tigran Kalaydzhyan
(University of Illinois at Chicago)
Testing gravity on accelerators

Weak equivalence principle (WEP) is one of the cornerstones of the modern theories of gravity, stating that the trajectory of a freely falling test body is independent of its internal structure and composition. Even though WEP is known to be valid for the usual matter, it has never been experimentally confirmed for antimatter and relativistic matter. We make an attempt to constrain possible deviations from WEP utilizing the modern accelerator technologies. We analyze the (absence of) vacuum Cherenkov radiation, photon decay and anomalous synchrotron losses at the Large Electron-Positron Collider (LEP) and at Tevatron to put limits on a difference between the gravitational and inertial masses of the relativistic electrons/positrons. Our main result is the 0.1% upper limit on the mentioned difference. I will further explain how this figure can be improved with the analysis of a high-energy Compton scattering at the future International Linear Collider (ILC).

August 4, 3h30PM
Thursday
J. Meng
(Peking University)
Covariant density functional theory for nuclear structure

Thomas Kuo
July 27, 1PM
Wednesday
Michael Lublinsky
(Ben-Gurion University)



July 15, 1PM
Friday
Song Shu
(Stony Brook)
One loop quantum fluctuations to the energy of the non-topological soliton in Friedberg-Lee model

I have used a practical method to calculate the one-loop quantum correction to the energy of the non-topological soliton in Friedberg-Lee model. The quantum effects which come from the quarks of the Dirac sea scattering with the soliton bag are calculated by a summation of the discrete and continuum energy spectrum of the Dirac equation in the background field of soliton. The phase shift of the continuum spectrum is numerically calculated in an efficient way and all the divergences are removed by the same renormalization procedure.

July 12, 1PM
Tuesday
Matti Järvinen
(École Normale Supérieure)
Magnetic field and theta dynamics in holographic QCD

I will start by an introduction to holographic QCD, concentrating on bottom-up models where the backreaction of quarks to gluon dynamics is fully included (V-QCD). I go on turning on a finite temperature and magnetic field, and demonstrate that inverse magnetic catalysis can be obtained. The physics of theta angle and axial anomaly can also be consistently included. In the limit of small quark mass, the predictions of the model agree with effective field theory: in particular the mass of the pions obey the Gell-Mann-Oakes-Renner relation and the eta-prime meson obeys the Witten-Veneziano relation.
René Meyer
July 7, 12h30PM
Thursday
Rasmus Larsen



June 28, 1PM
Tuesday
Gabor Almasi
(GSI/BNL)
Fluctuations as probes of the chiral phase transition

Fluctuations of conserved charges are important observables that offer insight into the phase structure of strongly interacting matter. Around critical points, such as the chiral critical endpoint of QCD, higher order cumulants of the relevant quantities show universal behavior. The universal behavior of baryon number cumulants can be studied in effective models that lie in the same universality class as QCD. Such a model is for example the Quark Meson model. In my talk I discuss what one can learn from effective field theory studies of fluctuations and present my results obtained using the Functional Renormalization Group method in the Quark Meson model.
J.-F. Paquet
June 22, 1PM
Wednesday
Bin Wu
(Ohio State University)
Leading log resummation in high-energy parton production in QCD matter

In this talk I shall start with the double logarithmic correction to the transverse momentum broadening of high-energy parton in QCD matter. Such a double logarithmic term, averaged over the path length of the partons, can be taken as the radiative correction to the jet quenching parameter $\hat{q}$ and contributes to radiative energy loss. Then, I shall talk about how such a double log is hidden in the small-x evolution of a quark-antiquark dipole described by the Balitsky-Kovchegov equation in a large nucleus. At the end, I shall discuss that the small-x WW quark distribution includes such a medium double log as well as Sudakov double logs.
J.-F. Paquet
June 14, 1PM
Tuesday
Stefan Rechenberger
(Darmstadt/BNL)
The Functional Renormalization Group Method and Delayed Magnetic Catalysis

This talk will start with a very general introduction to the Functional Renormalization Group method, a powerful non-perturbative tool which can be applied to various problems. The second part of the talk will demonstrate this by discussing the influence of an external magnetic field on the chiral phase transition in the theory of strong interaction. The Functional Renormalization Group analysis shows that, driven by gluon dynamics, the chiral critical temperature decreases for small values of the magnetic field. For large values of the external field, however, the phase transition temperature increases.
J.-F. Paquet
June 6, 1PM
Monday
Yachao Qian
(Stony Brook University)
Form Invariance, Topological Fluctuations and Mass Gap of Yang-Mills Theory

Ismail Zahed
June 3, 12h
Friday
Takumi Iritani
(Stony Brook University)
Baryon interaction from lattice QCD

Baryon interactions are important quantities in nuclear physics. Both Luscher's finite volume method and HAL QCD method are used to calculate hadron interactions from lattice QCD. However, these two approaches give different results for nucleon-nucleon system in the previous studies. For example, at unphysical pion mass, deuteron and dineutron become bound states in Luscher's method, while both channels are unbound in HAL QCD approach. In this talk, I will clarify this puzzle, and show how to approach baryon interactions from lattice QCD correctly. I will also review recent progress of baryon potentials at physical pion mass from lattice QCD by HAL QCD Collaboration.

June 2, 3h30PM
Thursday
Sören Schlichting
(Brookhaven National Lab)
Non-equilibrium dynamics of topological transitions and axial charges J.-F. Paquet
May 18, 12h
Wednesday
Aleksas Mazeliauskas
(Stony Brook)
Initial conditions for hydrodynamics from weakly coupled pre-equilibrium evolution

We use effective kinetic theory, accurate at weak coupling, to simulate the pre-equilibrium evolution of transverse energy and flow perturbations in heavy-ion collisions. We provide a Green function which propagates the initial perturbations to the energy-momentum tensor at a time when hydrodynamics becomes applicable. With this map, the complete pre-thermal evolution from saturated nuclei to hydrodynamics can be modelled in a perturbatively controlled way.
[https://arxiv.org/abs/1605.04287]

May 16, 12h30
Monday
Heikki Mantysaari
(Brookhaven National Lab)
Incoherent diffraction as a probe of proton structure fluctuations

Exclusive vector meson production can be used to directly probe the gluon density of a hadron. Measuring the cross section differentially in momentum transfer makes it possible to determine the transverse density profile (via coherent diffraction) and density fluctuations (incoherent diffraction) of the target hadron. This knowledge of the geometric fluctuations of the proton is particularly important for understanding collective phenomena observed in proton-nucleus collisions.

We calculate coherent and incoherent diffractive vector meson production in photon-proton scattering in the Color Glass Condensate framework. The dipole model used in the calculation is constrained by the proton structure function data. By implementing sub-nucleon scale fluctuations using the constituent quark model or the IP-glasma framework we demonstrate that incoherent gamma-p scattering measurements from HERA suggest that the proton shape has large event-by-event fluctuations.
J.-F. Paquet
April 28, 4PM
Thursday
Daniel Tapia Takaki
(University of Kansas)
Nuclear gluon effects in gamma+Pb collisions at the LHC

By studying quarkonia photo-nuclear production, the ALICE and CMS collaborations have recently provided experimental evidence of nuclear gluon effects in gamma+Pb interactions at unprecedentedly low Bjorken-x values in the Pb nucleus. In this talk, an experimental and theoretical review about these studies will be given. The prospect of innovative quarkonia and jet measurements using the Run 2 data at the LHC will be described.
Abhay Deshpande
April 28, 10AM
Thursday
Gökçe Başar
(University of Maryland)
Going with the flow: sign problem, Lefschetz thimbles and beyond

Monte Carlo methods, a robust way of studying field theories and many body systems, suffer from the sign problem when the action is complex. This includes an important set of problems such as most field theories, including QCD, and strong correlated electronic systems at finite density, as well as computation of real time quantities like transport coefficients. I will show that lifting the path integration to a complex manifold provides a way to ameliorate the sign problem, and introduce a new algorithm for carrying on such a computation. I will give some quantum mechanical examples with severe sign problems, including finite density of fermions and real time observables where Monte Carlo simulations can be profitably performed by this method. Finally I will discuss the 3+1d Bose gas with nonzero chemical potential.

April 27, 13h
Wednesday
Mauricio Adrian Ruis
(University of Minnesota)
Two charges in a magnetic field


April 22, 12h30
Friday
Rene Meyer
(Stony Brook)
Holographic Yang-Mills-Chern-Simons Defects

Chern-Simons gauge theories in 3 dimensions are an important class of quantum field theories, both because they (and their matter extensions) offer some of the few solvable QFTs in more than 2 dimensions, and because of their real-world applications in condensed matter theory.
In this talk we will discuss domain walls that shift the value of the Chern-Simons level in field theories described in the IR by Chern-Simons-Yang-Mills theory, and their embedding in gauge/gravity correspondence in terms of D7 branes on the AdS soliton geometry. After carrying out holographic renormalization to evaluate the free energy with sources, we evaluate the behavior of correlation functions on and between defects, and from this derive interesting phase transitions as a function of defect separation and temperature. We will also comment on possible implications for the fractional quantum hall effect and a connection to 2d (holographic) QCD.

April 8, 12h30
Friday
Mark Mace
(Stony Brook/BNL)
Sphalerons Far From Equilibrium and Associated Phenomena

In this talk, I will present a first computation of sphalerons in the glasma; the highly occupied, weakly coupled gluon dominated pre-equilibrium matter created at early times after an ultra-relativistic heavy ion collisions. The sphaleron transition is a well known ingredient in the generation of anomalous vector current in a strong magnetic field, the so-called Chiral Magnetic Effect. We perform classical-statistical real-time lattice simulations to study the dynamics of these topological transitions; simplifying our description by employing SU(2) gauge fields and neglecting the longitudinal expansion for this first study. I will show that the non-equilibrium sphaleron transition rate is time dependent and non-Markovian, in addition to being dominant in comparison to the thermal equilibrium sphaleron transition rate. In addition, we can measure the scaling and separation of physical scales in analogy to those from thermal equilibrium, in order to parameterize this rate and understand the approach to equilibrium. I will then demonstrate that it is the magnetic screening length, which we extract non-pertrubatively, that controls this rate. Additionally, I will briefly mention studies of related anomalous transport effects that we plan on studying using this first principles classical-statistical real-time lattice technology.

March 3, 3h30PM
Thursday
Yuta Kikuchi
(Stony Brook)
Mesoscopic dynamics of fermionic cold atoms: quantitative analysis of transport coefficients and relaxation times

We give a quantitative analysis of the shear viscosity, heat conductivity, and viscous relaxation times, using the novel microscopic expressions derived by the renormalization group (RG) method, where the Boltzmann equation is faithfully solved to extract the hydrodynamics without recourse to any ansatz. We examine the quantum statistical effects, temperature dependence, and scattering-length dependence of the transport coefficients and the viscous relaxation times. The numerical calculation shows that the relation $\tau_\pi=\eta/P$, which is derived in the relaxation-time approximation (RTA) and is used in the most literature, turns out to be satisfied quite well, while the similar relation for the viscous relaxation time $\tau_J$ of the heat conductivity is satisfied only approximately with a considerable error.

February 18, 3h30PM
Thursday
Niklas Mueller
(BNL/Heidelberg)
Anomaly-induced dynamics in strong field QED

We investigate the impact of the Adler-Bell-Jackiw axial anomaly on the real-time dynamics of quantum electrodynamics in the strong field regime. While it is known that there is no net production of axial charges in equilibrium situations, we show that there are intriguing consequences if one considers the far-from-equilibrium dynamics. Using real-time lattice simulations we study the evolution of the electromagnetic field for initial conditions which lead to the production of vector and axial charges via the Schwinger effect and the axial anomaly. We show that the Chiral Magnetic Effect, which has been predicted in the context of ultra-relativistic heavy ion collisions, can result in non-trivial experimental signatures, which could possibly be observed in future high-intensity laser experiments. Further I will give an outlook and first results on anomalous particle production in non-Abelian backgrounds as a first step towards the investigation of the Chiral Magnetic Effect using real-time lattice methods.
Dima Kharzeev
February 12, 12h
Friday
Matthew Lippert
(Long Island University - Brooklyn)
Phases of Holographic QCD

This talk will be a review of holographic QCD, focused primarily on the Sakai-Sugimoto model. I will explain the strengths and weaknesses of the Sakai-Sugimoto model, especially as compared with other holographic models, and I will present the results of the phase diagram at nonzero baryon charge.
Rene Meyer
February 11, 3h30PM
Thursday
Takumi Iritani
(Stony Brook)
Finite temperature phase transition of Nf = 3 SU(3) gauge theory with exact center symmetry

Confinement is often discussed in terms of center symmetry, however, quarks break this symmetry explicitly, and there are no definite order parameters for "confinement". In this talk, we introduce a formulation of center symmetric QCD-like theory with quarks by introducing specific boundary conditions. We discuss center and chiral phase transitions of such QCD-like theory at finite temperature from lattice QCD calculation.

January 29, 12h30PM
Friday
Yukinao Akamatsu
(Stony Brook)
Kinetic regime of hydrodynamic fluctuation and renormalization
January 15, 12h30PM
Friday
Rasmus Larsen
(Stony Brook)
Confinement and Chiral symmetry breaking from an Interacting Instanton-dyon ensemble for 2 colors and Nf flavors
January 14, 4PM
Thursday
Ismail Zahed
(Stony Brook)
Flow in spectra (part 2)
January 11, 1PM
Monday
Ismail Zahed
(Stony Brook)
Flow in spectra (part 1)
January 8, 12h30PM
Friday
Edward Shuryak
(Stony Brook)
New semiclassical method for QM and QFTs
December 4 Sergey Syritsyn TBA Robert Shrock
December 2 Huey-Wen Lin Frontiers in Lattice Nucleon Structure Robert Shrock
November 30 Yasumichi Aoki TBA Robert Shrock
October 8, 4PM J. Noronha TBA
October 9, 1PM Jacob Sonnenscheim TBA
October 13, 1PM Jacob Sonnenschein TBA
September 17, 4PM Yukinao Akamatsu Heavy Quarks in the QGP as Open Quantum Sys Edward Shuryak
September 11, 1PM Song Shu Chiral Solitons Edward Shuryak
September 3, 4PM Stanislaw Glazek Asymptotic Freedom of Gluons in the Fock Space Dima Kharzeev