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Events on Friday, February 11th, 2022

Theory Seminar (High Energy/Cosmology)
A Puncture in the Euclidean Black Hole
Time: 1:00 pm - 2:00 pm
Place: Chamberlin 5280
Speaker: Yoav Zigdon, Ben-Gurion University of the Negev
Abstract: We consider the backreaction of the winding zero mode on the cigar geometry. We focus on the case of the $SL(2,R)_k/U(1)$ cigar associated with e.g. the near-horizon limit of k NS5 black-branes. We solve the equations of motion numerically in the large k limit as a function of the amplitude of the winding mode at infinity. We find that there is a critical amplitude $A_c=\exp(-\gamma/2)$ that admits a critical solution. In string theory, the exact CFT description of the $SL(2,R)_k/U(1)$ cigar, fixes completely the winding amplitude, $A_s$, at infinity. We find that in the large $k$ limit there is an exact agreement $A_c=A_s$. The critical solution is a cigar with a puncture at its tip; consequently, the black hole entropy is carried entirely by the winding condensate. We comment on the Lorentzian interpretation of the solution.
Host: George Wojcik
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Physics Department Colloquium
Search for an Excess of Electron Neutrino Interactions in MicroBooNE Using Multiple Final State Topologies
Time: 3:30 pm
Place: 2103 Chamberlin Hall
Speaker: Bryce Littlejohn, IIT
Abstract: I will present a measurement of electron neutrino interactions from the Fermilab Booster Neutrino Beam using the MicroBooNE liquid argon time projection chamber performed to address the nature of the excess of low energy interactions observed by the MiniBooNE collaboration. Observation of an excess of electron neutrino detections in MicroBooNE would represent clear evidence of new physics in the neutrino sector, such as the existence of new neutrino mass states beyond those associated with the three Standard Model neutrinos. Three independent electron neutrino searches were performed by MicroBooNE across multiple single electron final states, including an exclusive search for two-body scattering events with a single proton, a semi-inclusive search for pion-less events, and a fully inclusive search for events containing all hadronic final states. With differing signal topologies, statistics, backgrounds, reconstruction algorithms, and analysis approaches, the results are found to be consistent with the nominal electron neutrino rate expectations from the Booster Neutrino Beam and no excess of electron neutrino events is observed. I will summarize important details of MicroBooNE's new centerpiece result, while also providing some broader context on its impact on searches for physics beyond the Standard Model in the neutrino sector.
Host: Brian Rebel
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