<p>Joint Theory Seminar Speaker: Nicholas Rodd (UC Berkeley)<br />mail: nrodd@berkeley.edu<br />Title: vidence the 3.5 keV line is not from dark matter decay<br />Host: Verhaaren<br />Room: 432<br />Abstract: X-ray observations of nearby clusters and galaxies have reported an unexpected X-ray line around 3.5 keV. This line has received significant attention due to its possible explanation through decaying dark matter; in particular, decaying sterile neutrino models, with a sterile neutrino mass around 7 keV, provide a good fit to the available data. We use over 30 Ms of XMM-Newton blank-sky observations to search for evidence of the 3.5 keV line consistent with arising from decaying dark matter within the ambient halo of the Milky Way. We find the strongest limits to-date on the lifetime of dark matter in this mass range, strongly disfavoring the possibility that the 3.5 keV line originates from dark matter decay.</p>
<p>Joint Theory Seminar Speaker: Dean Robinson (UCSC & LBL)<br />mail: drobinson@lbl.gov<br />Title: <strong>Sterile Neutrinos from Heavy Flavor Anomalies</strong><br />Host: Verhaaren<br />Room: 432<br />Abstract: Signals of lepton flavor universality violation are currently observed in semi-tauonic B decays at approximately the 3-4 sigma level compared to theoretically clean Standard Model (SM) predictions. I'll discuss the possibility that the semi-tauonic decay involves a sterile, right-handed neutrino, rather than a left-handed SM one, permitting simpler UV complete explanations with relaxed constraints. I'll survey the space of possible simplified models involving this sterile neutrino, along with relevant flavor, collider and cosmological bounds, and a possible flavor-safe UV completion.</p>
<p>Speaker: David Moseley</p><p>Institution: CEO of Seagate</p><p>Title:</p><p>Host: Bob Svoboda </p><p>Room: Alpha-Gamma-Rho, Alumni Center</p><p>Abstract: </p>
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High-Energy Seminars
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12:10pm - 1:10pm
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<p>Particle Physics Seminar Speaker: Albert de Roeck</p><p>Institution: CERN</p><p>Title: Searches of New Physics with Fixed Target and Beam Dump Experiments</p><p>Host: Robin Erbacher</p><p>Room: 185</p><p>Abstract: In 2016 CERN launched the "Physics Beyond Collider" initiative, to prepare <br />input for the European Strategy for Particle Physics update process in 2019-2020.<br />The initiative called for input and proposals on how to use the CERN facilities in future, <br />in particular its accelerator park -- with upgrades-- for a competitive physics program in <br />the next 10-15 years, based eg on high intensity beams and a beam dump facility.<br />Both proposal for hadron physics, and searches for physics beyond the Standard Model <br />in the small coupling-low mass regime were scrutinised, and a summary report was <br />contributed to the ESPP process last December.</p>
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High-Energy Seminars
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4:10pm
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<p>Particle Physics Seminar <br />Speaker: Albert de Roeck</p><p>Institution: CERN</p><p><br />Title: TBA</p><p><br />Host: TBA</p><p><br />Room: 285</p><p><br />Abstract: </p>
<p>Joint Theory Seminar Speaker: Albert Schwarz<br />mail: aschwarz@gmail.com<br />Title: Thermo-field dynamics and collisions of quasi-particles<br />Host: John Terning<br />Room: 432<br />Abstract:</p><p>The quantum theory can be formulated in the language of positive functionals on Weyl or Clifford algebra (L-functionals). It is shown that this language gives simple understanding of diagrams of Keldysh formalism (that coincide in our case with the diagrams of thermo-field dynamics). The matrix elements of the scattering matrix in the formalism of L-functionals are related to inclusive cross-sections, therefore we suggest the name "inclusive scattering matrix" for this notion.</p><p>The inclusive scattering matrix can be expressed in terms of on-shell values of generalized Green functions. This notion is necessary if we want to analyze collisions of quasiparticles.</p>