Seminars 2023-24

Abstract: Composite states occur over vast scales and play an important role in various domains of particle physics. In the first part I report on the recent development and application of non-relativistic QCD for the study of hadrons and multi-hadron systems in QCD and beyond. In particular, I will demonstrate how we obtain quantities such as binding energies, mass spectra and color scaling for heavy bound states. The techniques we employ are highly computationally efficient and thus can provide reliable estimates of properties of heavy baryons and multi-hadron systems, as well as dark baryons without the need for computationally intensive lattice QCD calculations. In the second part I introduce a chiral SU(15) gauge theory in which the SM quarks and leptons emerge as bound states of massless preons below a large confining scale. We show how under certain assumptions di-prebaryon bound states behave as Higgs fields and that proton-decay operators are likely induced at the compositeness scale. We find dominant exotic proton decay modes involving heavy right-handed neutrinos which could be observed using the Super-K or DUNE detectors. 

Abstract: The existence of Dark Matter is well established from astronomical observations, but its observation at particle colliders has remained elusive. The observation of the decay of an unknown, long-lived particle would be a compelling signature for many new-physics scenarios, including models for Dark Matter. Existing experiments have limited sensitivity to such decays, however, suggesting the need for new strategies.

The COmpact Detector for EXotics at LHCb (CODEX-b) would be a dedicated experiment near the LHCb detector at CERN's Large Hadron Collider (LHC), the only collider currently capable of producing Higgs Bosons. It would be located far from and transverse to the LHC beam line, and it would be shielded from the collision point, making it uniquely sensitive to long-lived particles produced in the decay of Higgs Bosons.

I here make the physics case for CODEX-b. I also present the status of its associated prototype, CODEX-β, currently under construction.

Abstract: To appear.

Abstract: FASER is a small experiment at the LHC designed to search for new light, extremely weakly-interacting particles at CERN's Large Hadron Collider (LHC), as well as measure the interactions of Standard Model neutrinos. The experiment specifically targets new particles produced in the very forward direction in LHC's high energy proton-proton collisions, that subsequently decay to visible particles inside the FASER detector. The detector lies in wait 480 m downstream of the ATLAS interaction point, aligned with the beam collisions axis. During the seminar, I will present the FASER detector design, operational experiences and first results, which include new constraints on Dark Photons decaying to leptons, as well as observations of collider neutrino interactions in FASER.

Abstract: Event generators have become an essential part of understanding and testing the Standard Model of particle physics.  In this talk, I will introduce the Pythia8 event generator, explain how it is used in analyses, and comment on its evolution in face of new data.

Abstract: Starting in 2029, the High Luminosity LHC (HL-LHC) era will begin. Over its lifetime, the HL-LHC will increase the luminosity of the LHC by a factor of 10, allowing rare phenomena to be observed and measured for the first time. In order to perform these measurements, the LHC detectors are being upgraded. In this seminar, I will discuss the upgrade of the innermost system of the ATLAS detector - the inner tracker (Itk). I will describe how this detector will handle the harsh radiation environment of the HL-LHC and the ways in which it will further our physics goals. Finally, I will describe my role in building this new ATLAS inner tracker. .

Abstract: Direct decays of proposed heavy force mediator particles to standard model (SM) leptons have been excluded to high masses [1], but more exotic interactions and decays remain unexplored. I will present a search for one such exotic alternative: a leptophobic Z’ decaying via anomalons in proton-proton collisions at √s = 13 TeV with the Compact Muon Solenoid (CMS) Experiment. A leptophobic Z’ can decay via a pair of anomalons, new beyond the standard model (BSM) fermions introduced to cancel the gauge anomalies arising from the leptophobic condition. These heavy intermediate particles decay in turn to neutral SM bosons and lighter, stable anomalons that serve as a dark matter candidate. This analysis targets the Z(μμ)H(bb)+MET final state in a total  integrated luminosity of 137.6 fb-1 corresponding to the 2016-2018 data set. To search for the resonant Z’ production, this analysis employs Recursive Jigsaw Reconstruction (RJR), an iterative framework to reconstruct mass estimators in systems with invisible particles in the final state. I will present the expected sensitivity of this novel model and observable in a CMS search. Additionally, the assembly, installation, and commissioning of CMS Hadron Calorimeter Phase 1 upgrade will be discussed.

[1] CMS Collaboration. “Search for resonant and nonresonant new phenomena in high-mass dilepton final states at √s= 13 TeV”. In: Journal of High Energy Physics 2021.208 (June 2021). doi: 10.1007/JHEP07(2021)208. url: https: //doi.org/10.1007/JHEP07(2021)208. 

Abstract: Secondary anisotropies of the cosmic microwave background (CMB) are known to be remarkable probes of astrophysics and cosmology. The properties of free streaming CMB photons from the surface of last scattering are altered by their interaction with matter in the Universe carrying crucial information about the the epoch of reionisation and also the origin, growth, and evolution of structures. In this talk, I will discuss the potential of a couple of these secondary anisotropies, namely the kinematic and thermal Sunyaev-Zeldovich (SZ) effects, to shed light into some of the long-standing cosmological quests like the physics of reionisation and the properties of dark energy. I will also demonstrate the challenges posed by astrophysical foregrounds for the detection of these small-scale anisotropies and discuss strategies for mitigating them. Finally, I will discuss some of the ongoing work to constrain reionsation with kSZ using the South Pole Telescope and then present the prospects of SZ science with future CMB surveys like the CMB-S4 experiment. 

Abstract: Evidently, magnetic moments are successful probes for uncovering new physics. The precision measurement of the anomalous magnetic moment of the muon, aμ= (gμ−2)⁄2 , continues to play an important role in particle physics. Analyzing the data from 2019 and 2020 Fermilab accelerator operation years, the Fermilab Muon g-2 Experiment has measured the magnetic anomaly for the positive muon to unprecedent precision at 215 parts per billion. The experiment reports a total systematic uncertainty of 70 parts per billion. This value surpasses the proposal goal of 100 parts per billion. The measurement is consistent with the results produce from the 2018 data taking period. Combining with Fermilab previous measurement and Brookhaven National Laboratory experimental value, the new world’s average for muon g-2 is aμ= 116592059(22)(0.19 ppm). This talk presents an overview of the Fermilab Muon g-2 Experiment, the procedure for extracting the anomalous magnetic moment of the muon and a comparison between 2021and 2023 published results. Finally, the presentation will speak briefly on the Standard Model prediction, which has cause conflicts over the past two years.

Abstract: The DUNE physics program primarily focuses on signals in the GeV energy range. In recent years, DUNE's potential as a low-energy experiment has been explored expecting some sensitivity to signals as low as 5-10 MeV such as supernova burst and solar neutrinos. In this presentation I discuss the requirements and modifications that could extend DUNE's sensitivity to energies as low as 2MeV which would enhance DUNE's physics program and could expand it to enable searches for neutrino-less double-beta decay in xenon-doped liquid argon. I will present the modifications we propose with corresponding sensitivity estimates for measurements of the absolute neutrino mass scale (mββ) beyond the sensitivities expected from current and next generation neutrino-less double beta decay experiments. I will describe the rich R&D program that this research avenue would open for DUNE in the coming years.