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Theory Seminar

Baryogenesis, Dark Matter, Neutron-Antineutron Oscillation and Collider Signals

We will discuss a simple model of low-energy baryon number violation in order to simultaneously explain the observed matter-antimatter asymmetry and dark matter relic density in the universe. The stability of dark matter is related to the stability of the proton. The model predicts a sizeable rate for the neutron-antineutron oscillation at low energy and a new type of monojet signal at the LHC. There exists an interesting complementarity between the observed baryon asymmetry, ratio of dark matter and baryon abundances, neutron-antineutron oscillation lifetime and the LHC monojet signal. 

Date:
-
Location:
CP 179

Theory Seminar

Title: Baryogenesis, Dark Matter, Neutron-Antineutron Oscillation and Collider Signals

Abstract: We will discuss a simple model of low-energy baryon number violation in order to simultaneously explain the observed matter-antimatter asymmetry and dark matter relic density in the universe. The stability of dark matter is related to the stability of the proton. The model predicts a sizeable rate for the neutron-antineutron oscillation at low energy and a new type of monojet signal at the LHC. There exists an interesting complementarity between the observed baryon asymmetry, ratio of dark matter and baryon abundances, neutron-antineutron oscillation lifetime and the LHC monojet signal. 

Date:
-
Location:
CP-179
Tags/Keywords:
Event Series:

Theory Seminar

Title : Rotating traversable wormholes

Abstract : An interaction that couples the two boundaries of  an eternal BTZ black hole produces a violation of the average null energy condition and makes the wormhole traversable. I will review this scenario and present work in progress where we consider a rotating black hole. We study the effect of rotation in the size of the wormhole and the amount of information transferred.

Date:
-
Location:
CP 179
Tags/Keywords:
Event Series:

Theory Seminar

Title: A string-inspired SYK model and some 4d black hole phenomenology

Abstract: String compactifications to four dimensions provide us with very rich quantum systems with couplings determined by Calabi-Yau data. For very complicated Calabi-Yau manifolds these couplings can be treated as a disorder, similar to the disordered couplings in SYK. We show that these systems admit an emergent SL(2,R)-invariant IR fixed-point at large N upon disorder averaging. The global symmetry of our system is SO(3) and we show that there exist marginal deformations that break the SO(3) but preserve the SL(2,R) in the IR. We connect this to the phenomenology of charged rotating extremal black holes in four dimensions. 

Date:
-
Location:
CP 111
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Theory Seminar: BRST vs. EPR - The Maxwell Story

The question of whether entanglement entropy in gauge theories is BRST invariant has an odd answer: two different representatives of a BRST cohomology class have different entanglements, but the replica trick path integral commonly used to calculate entanglement is invariant under BRST transformations. After short introductions to entanglement in gauge theories and Hamiltonian BRST quantisation, I will explain why this is so and how it evades the usual arguments about the equivalence between the path integral and the Hamiltonian pictures. Finally, I will comment on the possibility of a prescription to "fix" the Hamiltonian calculation -- to make it BRST-invariant and equal to the answer given by the replica trick.

Date:
-
Location:
CP-179
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Theory Seminar: CP-Symmetry and Baryon number violation in Nucleons on a Lattice

One of the main frontiers of Nuclear Physics is searching for violations of fundamental symmetries such as parity and time reversal. These symmetries have to be broken at the level above the Standard Model prediction, otherwise it will be hard to explain the observed amount of nuclear matter in the Universe. Measurements of the electric dipole moment (EDM) of nucleon, nuclei, and atoms are the most promising ways to observe CP-symmetry violations in the quark-gluon sector. Several experiments plan to improve the bound on the neutron EDM by two orders of magnitude in the next decade. Another vital condition for the baryogenesis is the violation of the baryon number, which, despite extensive several decade-long searches for proton decays and neutron oscillations, has never been observed. Interpreting these experimental limits in terms of fundamental particles and their interactions requires robust theoretical understanding of hadron structure. Thanks to mature numerical methods of solving QCD on a lattice, we can now investigate effects of non-Standard Model quark-gluon interactions on the properties of protons and neutrons. I will present our recent progress in calculations of nucleon EDM induced by quark-gluon color-electric dipole interaction (quark chromo-EDM) performed in QCD with physical masses of quarks and discretization preserving chiral symmetry. In addition, I will present results for the neutron-antineutron oscillation amplitudes and its implications for BSM phenomenology.

Date:
-
Location:
CP-179
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Theory Seminar: Soft Black Hole Absorption Rates as Ward Identities

Recently, a number of exciting connections have been made between large gauge transformations (eg. BMS) and infrared physics (eg. Weinberg's soft graviton theorem). One of the more exciting explorations in this vein was Hawking-Perry-Strominger's (HPS) investigation of the consequences of these new symmetries for black hole physics. I will show very concretely that the Ward identity for the BMS-like large U(1) gauge transformations discussed by HPS fixes the low energy black hole absorption rate for photons. Time permitting, I will discuss broader implications and future extensions.

Date:
-
Location:
CP-179
Tags/Keywords:
Event Series:
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