The High Energy Particle Physics group participates in regular seminars with our colleagues at OSU, discussing research and news in the field. Students who are studying high energy physics at OU are strongly encouraged to participate.
The seminar and journal club are being temporarily combined, to be held on Tuesdays at 1:00 pm in Lin Hall 105 on the OU Norman campus.
If you have questions about the seminar, please contact Kuver Sinha at Kuver.Sinha@ou.edu or by phone at (405) 325-7095.
Title: "Not-quite-primordial black holes"
Abstract: In this talk, I will discuss a new mechanism for the formation of seeds of supermassive black holes at early cosmic epochs. Enhanced density fluctuations with amplitudes that are not large enough to form primordial black holes post-inflation can still lead to collapsed dark matter halos at very early times. For halos forming prior to 1+z ~ 200, the Cosmic Microwave Background (CMB) is energetic enough to suppress the formation of molecular hydrogen, hence preventing cooling and fragmentation, as a consequence of which baryons falling into the potential well of the halo may undergo “direct collapse" into a black hole. I will show using a few illustrative models how this mechanism may account for the abundance of high-redshift black holes inferred from observations by the James Webb Space Telescope while remaining consistent with current limits from CMB spectral distortions. Limits on the primordial power spectrum are also derived by requiring that the universe not reionize too early.
Title: "AMSB for Strong Dark Sector Model Building"
Abstract: In recent years we have used Anomaly-mediated SUSY breaking (AMSB) to obtain exact results about the strongly-coupled phases of many non-SUSY gauge theories. Particularly interesting is the application to gauge theories for which an analogy with known results in QCD is not available. I will explain how these results can be used for novel dark matter model building. First I will give examples where AMSB gives us qualitative information about a theory (symmetry breaking patterns, low-energy d.o.f., etc.) that can be used to inform an effective description of a dark sector. After that, we will take the AMSB scenario as physical and leverage the ability to directly compute phenomenologically relevant quantities (decay constants for example).
Title: "Continuous Spin Particles and New Physics at Low Energies"
Abstract: The most general massless particle admitted by Lorentz Invariance and Quantum Mechanics is the “Continuous Spin Particle” (CSP). A CSP has an infinite number of discretely spaced helicity states which mix under the little group, and hence under Lorentz transformations. The magnitude of mixing is controlled by a new fundamental parameter, the spin-scale - $\rho$. The free field theory, its interactions and preliminary phenomenology was introduced over the past decade. The observables computed demonstrate a trend of recovering the physics similar to that of familiar massless particles at high energies, with deviations at lower energies. In this talk, I will talk about the leading order corrections to CSP mediated gravity, and the interaction of a CSP with a spinning degree of freedom and some of its simple phenomenology, noting that in both cases, the observables show a deviation from expectations at low energies.
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