Events on Tuesday, October 29th, 2024
- Theory Seminar (High Energy/Cosmology)
- Detecting Ultrashort Gamma-ray Bursts Originated from Ultraheavy Dark Matter Collisions
- Time: 11:00 am - 12:00 pm
- Place: 5310 Chamberlin Hall
- Speaker: Xuheng Luo, Johns Hopkins University
- Abstract: Dark matter may exist today in the form of ultraheavy composite bound states. Collisions between such dark matter states can release intense bursts of gamma-rays. Thus, indirect-detection signals of dark matter may include unconventional gamma-ray bursts. Such bursts may have been missed not necessarily because of their low arriving gamma-ray fluxes, but rather their ultrashort duration and rareness. In this talk, I will discuss the strategies and prospects for detecting such ultrashort gamma-ray burst. I will also present a concrete dark matter model that produces bursts potentially detectable by the current instruments.
- Host: Yang Bai
- Network in Neutrinos, Nuclear Astrophysics, and Symmetries (N3AS) Seminar
- SIMP Miracles and WIMP Dead Ends: Navigating the Freeze-Out of MeV Dark Matter
- Time: 2:00 pm - 3:00 pm
- Place:
- Speaker: Joseph Pradler, HEPHY, Vienna
- Abstract: In this talk we consider both the possibility of dark matter being either a strongly or a weakly interacting thermal relic. For strongly interacting massive particles (SIMPs) we study the influence of bound states X on their cosmology, finding a "catalysis" of mass-depleting processes in the hidden sector, adding a qualitative change to SIMP freeze-out once X exist, hence broadening the options for SIMP dark matter. In turn, for weakly interacting massive particles (WIMPs) we study the low mass frontier of thermal relics where freeze-out happens during the cosmological non-trivial epochs of neutrino decoupling and primordial nucleosynthesis. Here we present a first self-consistent calculation of the cosmological Neff parameter that is expected to be measured with much improved accuracy in upcoming CMB experiments.
NOTE: All participants and hosts are now required to sign into a Zoom account prior to joining meetings hosted by UC Berkeley.
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Meeting ID: 912 3071 4547 - Host: Balantekin
- High Energy Seminar
- Road to Minimal WIMPs
- Time: 3:00 pm - 4:00 pm
- Place: 5280 Chamberlin
- Speaker: Rodolfo Capdevilla Roldan, FNAL
- Abstract: Minimal WIMP models extend the Standard Model with an electroweak multiplet whose neutral component $\chi_0$ serves as Dark Matter (DM). Direct Detection (DD) and Indirect Detection (ID) searches probe these models especially when $\chi_0$ accounts for 100% of DM (the thermal target). Colliders aim to produce the charged members of the multiplet, which produce interesting signals when they decay. These searches are more effective when $\chi_0$ accounts for a fraction of DM, as this leads to a lower mass multiplet and larger production cross sections. This shows an interesting complementarity between DD, ID, and colliders. In this talk, I discuss the role that present and future colliders can play in discovering Minimal WIMPs. I show how a 3 TeV muon collider can discover the elusive doublet (Higgsino-like) state up to its thermal target. As the collider energy increases, larger multiplets become accessible. A 10 TeV muon collider could discover the triplet (Wino-like) state up to its thermal target as well as a quintuplet state that accounts for ~10% of DM. These results indicate an interesting path ahead towards the possible discovery of the long standing minimal WIMPs.
- Host: Yang Bai and Sridhara Dasu