CCAPP AstroParticle Lunch

Here, members of CCAPP, Physics, and Astronomy get together to discuss papers and recent developments in high-energy astrophysics and astroparticle physics, in an informal setting over lunch. Please check the page for details regarding the next meeting.

Organizers:

Fridays from 11:30 am - 12:30 pm (EST)

Price Place (PRB) & VIA ZOOM

• Talks signup schedule.

COMING UP:

11:30, Friday, September 5

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1. Convection-Driven Multi-Scale Magnetic Fields Determine the Observed Solar-Disk Gamma Rays

2. Cosmic-ray boosted inelastic dark matter from neutrino-emitting active galactic nuclei

3. Hillas meets Eddington: the case for blazars as ultra-high-energy neutrino sources 

4. Contribution of Globular Clusters to Diffuse Gamma-ray Emission from Galactic Plane 

5. Identification and Denoising of Radio Signals from Cosmic-Ray Air Showers using Convolutional Neural Networks 

6. Search for the radiative decay of the cosmic neutrino background through spectral measurements of the cosmic infrared background using PRIMA 

7. Testing the dark side of neutrino oscillations with the solar neutrino fog at Dark Matter experiments

8. High-Energy Neutrinos from Cosmic-Ray Scatterings with Supernova Neutrinos

9. Arecibo Wow! II: Revised Properties of the Wow! Signal from Archival Ohio SETI Data 

10. A multi-wavelength view of the multi-messenger sources NGC 1068 and PKS 1502+1061 '

11. Testing the heavy decaying sterile neutrino hypothesis at the DUNE near detector

12. Probing Turbulence, Gravity, Supernovae, and Magnetic Field Effects with the 6D Kinematics of Young Stars in Milky Way Star-Forming Regions

13. Ultra-luminous X-ray pulsars as sources of TeV neutrinos

14. Constraining Super-Heavy Dark Matter with the KM3-230213A Neutrino Event

15. Distinguishing between Dirac and Majorana neutrinos at FASER

PAST EVENTS:

11:30, Friday, April 25

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Guest: Rasmi Hajjar (CSIC-University of Valencia)

Title: Shedding light on the Δm221 tension with supernova neutrinos

Abstract: One long-standing tension in the determination of neutrino parameters is the mismatched value of the solar mass square difference, Δm221, measured by different experiments: the reactor antineutrino experiment KamLAND finds a best fit larger than the one obtained with solar neutrino data. Even if the current tension is mild (∼1.5σ), it is timely to explore if independent measurements could help in either closing or reassessing this issue. In this regard, we explore how a future supernova burst in our galaxy could be used to determine Δm221 at the future Hyper-Kamiokande detector, and how this could contribute to the current situation. We study Earth matter effects for different models of supernova neutrino spectra and supernova orientations. We find that, if supernova neutrino data prefers the KamLAND best fit for Δm221, an uncertainty similar to the current KamLAND one could be achieved. On the contrary, if it prefers the solar neutrino data best fit, the current tension with KamLAND results could grow to a significance larger than 5σ. Furthermore, supernova neutrinos could significantly contribute to reducing the uncertainty on sin2θ12.

11:30, Friday, April 18

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16. A ν look at the Sun: Probing the conditions of the solar core using 8B neutrinos 

17. Cosmic-Ray Constraints on the Flux of Ultra-High-Energy Neutrino Event KM3-230213A 

18. The Moon as a Cosmic-Ray Spectrometer: Prospects for MeV Gamma-Ray Observations 

19. Probing Long-Range Forces in Neutrino Oscillations at the ESSnuSB Experiment 

11:30, Friday, April 11

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Guest: Jeffrey Lazar (Université catholique de Louvain)

Title: Tau Neutrino Astronomy in the Peruvian Andes with TAMBO

Abstract: The detection of high-energy astrophysical neutrinos by IceCube has opened a new window on our Universe. While IceCube has measured the flux of these neutrinos at energies up to several PeV, much remains to be discovered regarding their origin and nature. Currently, the discovery of point sources of neutrinos is hindered by atmospheric neutrino backgrounds; likewise, astrophysical neutrino flavor ratio measurements are limited by the difficulty of discriminating between electron and tau neutrinos.

TAMBO is a next-generation neutrino telescope specifically designed to detect tau neutrinos in the 100 TeV to 1 EeV energy range. This tau neutrino specificity enables the low-background identification of astrophysical neutrino sources, as well as tests of the flavor ratio of astrophysical neutrinos. Additionally, the high-energy reach of TAMBO will allow us to probe models of cosmogenic neutrino production. TAMBO will comprise an array of water Cherenkov and plastic scintillator detectors deployed on the face of the Colca Canyon in the Peruvian Andes, with its unique geometry facilitating the high-purity measurement of astrophysical tau neutrinos. In this talk, I will present the particle physics and astrophysics that TAMBO will study in the context of next-generation neutrino observatories. I will also provide an update on the status of detector construction.

Guest: Akash Kumar Saha (Indian Institute of Science)

Title: Shedding Infrared Light on QCD Axion and ALP Dark Matter with JWST

Abstract: JWST observations have already revolutionized Infrared astronomy and astrophysics. Besides probing standard astrophysics, JWST observations can also be used to hunt for dark matter (DM). If DM is made up of eV-scale QCD axions or Axion-like particles (ALPs), then they can decay to two photons and the resulting line feature can contribute to the spectroscopic observations made by JWST. Using the existing JWST NIRSpec IFU observations, we are able to probe axions in mass ranges $\sim$ 0.47 and 2.55 eV. With this, we constrain well-motivated QCD axion and ALP-DM models. Future observations of DM-rich targets with a better understanding of the background will become powerful tools in discovering QCD axion and ALP DM.

11:30, Friday, April 4

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Guest: Andrew Gustafson (Virginia Tech)

Title: Impact of Dark Matter Scattering on High-Energy Particles

Abstract: Dark matter (DM) is known to comprise most of the mass in the universe, yet its exact nature remains a mystery. DM direct detection experiments search for the interactions of low energy (v≃10^-3 c) DM with electrons and nuclei. While these experiments set impressive constraints, there are many DM models which cannot be probed in this way i.e. light DM, DM with mass splittings, DM with primary couplings to other Standard Model (SM) particles. In this talk, I will explore higher energy DM interactions which result in measurable impacts on relativistic astrophysical SM particles. I will begin inelastic dark matter around an Active Galactic Nuclei and study the energy loss off the cosmic rays. Next, I will discuss how neutrino-coupled dark matter can lead to a diffuse neutrino flux from past Milky way supernovae. We will see that observations from multi-messenger astronomy place constraints on the particle properties of DM.

11:30, Friday, March 28

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Guest: Rui Hu ((Chinese University of Hong Kong)

Title: Impact of light sterile neutrinos on cosmological large scale structure

Abstract: Sterile neutrinos with masses on the eV scale are promising candidates to account for the origin of neutrino mass and the reactor neutrino anomalies. The mixing between sterile and active neutrinos in the early universe could result in a large abundance of relic sterile neutrinos, which depends on not only their physical mass but also their degree of thermalization, characterized by the extra effective number of relativistic degrees of freedom ΔNeff. Using neutrino-involved N-body simulations, we investigate the effects of sterile neutrinos on the matter power spectrum, halo pairwise velocity, and halo mass and velocity functions. We find that the presence of sterile neutrinos suppress the matter power spectrum and halo mass and velocity functions, but enhance the halo pairwise velocity. We also provide fitting formulae to quantify these effects.

Guest: Wangzheng Zhang (Chinese University of Hong Kong)

Title: Measuring the Hubble constant through the galaxy pairwise peculiar velocity

Abstract: The Hubble constant H0, the current expansion rate of the universe, is one of the most important parameters in cosmology. The cosmic expansion regulates the mutually approaching motion of a pair of celestial objects due to their gravity. Therefore, the mean pairwise peculiar velocity of celestial objects, which quantifies their relative motion, is sensitive to both H0 and the dimensionless total matter density Ωm. Based on this, using the Cosmicflows-4 data, we measured H0 for the first time via the galaxy pairwise velocity in the nonlinear and quasi-linear range. Our results yield H0=75.5±1.4 km s−1 Mpc−1 and Ωm=0.311+0.029−0.028 . The uncertainties of H0 and Ωm can be improved to around 0.6% and 2%, respectively, if the statistical errors become negligible in the future.

11:30, Friday, March 7

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Guest: Prof. Hy Trac (Carnegie Mellon University)

Title: Learning to See the Dark Matter in Galaxy Clusters

Abstract: Galaxy clusters contain vast amounts of cold dark matter, hot ionized gas, and tens to hundreds of visible galaxies. In 1933, Fritz Zwicky first proposed the existence of dark matter after observing the motions of galaxies in the Coma Cluster. Today, we estimate that dark matter makes up about 85% of the total matter in the Universe. However, the spatial distributions of dark matter and baryons within galaxy clusters remain uncertain. To address this, we first present an updated mass estimate of the Coma cluster using modern AI/ML techniques. We then show how generative diffusion models, trained on multi-wavelength images (e.g. SZ effect, X-ray emission, gravitational lensing), can predict the gas, dark matter, and total matter projected density fields. When applied to synthetic images of simulated clusters, these models produce accurate and unbiased mass maps. AI/ML offers a promising approach for mapping the unseen in galaxy clusters. Knowing where is the dark matter will help us to understand its nature and that of the Universe.

11:30, Friday, February 28

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11:30, Friday, February 21

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1. Cascaded Gamma-ray Emission Associated with the KM3NeT Ultra-High-Energy Event KM3-230213A 

2. Insights from leptohadronic modelling of the brightest blazar flare 

3. Measurement of the inelasticity distribution of neutrino-nucleon interactions for 80 GeV<Eν<560 GeV with IceCube DeepCore 

4. New Physics versus Quenching Factors in Coherent Neutrino Scattering 

11:30, Friday, February 14

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1. Observation of an ultra-high-energy cosmic neutrino with KM3NeT 

2. The ultra-high-energy event KM3-230213A within the global neutrino landscape 

3. On the potential cosmogenic origin of the ultra-high-energy event KM3-230213A 

4. On the Potential Galactic Origin of the Ultra-High-Energy Event KM3-230213A 

5. Characterising Candidate Blazar Counterparts of the Ultra-High-Energy Event KM3-230213A 

11:30, Friday, February 7

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Guest: Sarah Mancina (University of Padova)

Title: Time-Integrated Southern-Sky Neutrino Source Searches with 10 Years of IceCube Starting-Track Events at Energies Down to 1 TeV

Abstract: In the IceCube Neutrino Observatory, a signal of astrophysical neutrinos is obscured by backgrounds from atmospheric neutrinos and muons produced in cosmic-ray interactions. IceCube event selections used to isolate the astrophysical neutrino signal often focus on the morphology of the light patterns recorded by the detector. The analyses presented here use the new IceCube Enhanced Starting Track Event Selection (ESTES), which identifies events likely generated by muon neutrino interactions within the detector geometry, focusing on neutrino energies of 1-500 TeV with a median angular resolution of 1.4°. Selecting for starting track events filters out not only the atmospheric-muon background, but also the atmospheric-neutrino background in the southern sky. This improves IceCube’s muon neutrino sensitivity to southern-sky neutrino sources, especially for Galactic sources that are not expected to produce a substantial flux of neutrinos above 100 TeV. In this work, the ESTES sample was applied for the first time to searches for astrophysical sources of neutrinos, including a search for diffuse neutrino emission from the Galactic plane. No significant excesses were identified from any of the analyses; however, constraining limits are set on the hadronic emission from TeV gamma-ray Galactic plane objects and models of the diffuse Galactic plane neutrino flux.

11:30, Friday, January 31

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1. Gamma-Ray Observations of Galaxy Clusters Strongly Constrain Dark Matter Annihilation in Prompt Cusps 

2. Super-Kamiokande Strongly Constrains Leptophilic Dark Matter Capture in the Sun 

3. Dynamic Neutrino Mass Ordering and Its Imprint on the Diffuse Supernova Neutrino Background 

4. Influence of the Galactic Halo on the UHECR Multipoles 

11:30, Friday, January 24

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Guest: Jianhao Wu (The Chinese University of Hong Kong)

Title: Can blue-tilted primordial power spectrum save the small scale crisis in MW? – From the perspective of Zoom-In simulation for MW host size dark matter halo

Abstract: Recent observations from the James Webb Space Telescope revealed a surprisingly large number of galaxies formed at high redshift. Along with strong lensing studies and nearby galaxy observations, these could challenge the standard Lambda Cold Dark Matter cosmology with a power-law primordial power spectrum. In this study, we conduct high-resolution cosmological zoom-in dark matter-only simulations of Milky Way host size halos with a blue, tilted primordial power spectrum (P(k)∝k^ms with ms>1 at small scales >1 Mpc^−1). We find that the blue-tilted subhalo mass functions can be enhanced by more than a factor of two for subhalo masses Msub≲10^10 M⊙, whereas the subhalo Vmax functions can be enhanced by a factor of four for maximum circular velocities Vmax≲30 km/s. The blue-tilted scaled cumulative substructure fraction can be an order of magnitude higher at ~10% of the virial radius. The blue-tilted subhalos also have higher central densities, since the blue-tilted subhalos reach the same Vmax at a smaller distance Rmax from the center. We have also verified these findings with higher-resolution simulations.

1. Cosmological Zoom-In Simulations of Milky Way Host Size Dark Matter Halos with a Blue-Tilted Primordial Power Spectrum

2. Angular Distribution of Gamma Rays Produced in Proton-Proton Collisions

3. The LHC as a TeV Muon Beam Dump: Muonphilic Scalars at FASER 

4. The flux of electron antineutrinos from supernova SN1987A data

5. High-Significance Detection of Correlation Between the Unresolved Gamma-Ray Background and the Large Scale Cosmic Structure 

11:30, Friday, January 17

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1. Critical Condition of Core-Collapse Supernovae I: One Dimensional Models 

2. First observation of reactor antineutrinos by coherent scattering 

3. Widen the Resonance: Probing a New Regime of Neutrino Self-Interactions with Astrophysical Neutrinos 

4. Contribution of Unresolved Sources to Diffuse Gamma-Ray Emission from the Galactic Plane 

5. Observation of Cosmic-Ray Anisotropy in the Southern Hemisphere with Twelve Years of Data Collected by the IceCube Neutrino Observatory

6. Prospects for Observing Astrophysical Transients with GeV Neutrinos

7. Observation of a spectral hardening in cosmic ray boron spectrum with the DAMPE space mission 

8. First Measurement of the Muon Neutrino Interaction Cross Section and Flux as a Function of Energy at the LHC with FASER 

9. Composite asymmetric dark matter with a dark photon portal: Multimessenger tests