# Particle Physics

This series consists of talks in the areas of Particle Physics, High Energy Physics & Quantum Field Theory.

## Seminar Series Events/Videos

Currently there are no upcoming talks in this series.

## Quark Reggeization from Effective Field Theory

Tuesday May 02, 2017
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We derive in the framework of soft collinear effective field theory (SCET) a Lagrangian describing the t-channel exchange of Glauber quarks, which are incorporated through fermionic potential operators in the effective theory. The Wilson line structure of the operators, which is derived from matching calculations and the symmetries of the effective theory, describe additional soft and collinear emissions from a fermionic t-channel exchange in the forward scattering limit to all orders.

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## Discovering New Physics in Scattering Angles at the LHC

Tuesday Apr 18, 2017
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Since the Higgs, the LHC has offered no discoveries despite a sweeping hunt for new resonances.

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## New Directions in Dark Matter Direct Detection

Tuesday Apr 04, 2017
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Sub-GeV dark matter is a theoretically motivated but largely unexplored paradigm of dark matter. In this talk, I will discuss recent work on the direct detection of sub-GeV dark matter through dark matter-electron scattering. I will present some motivated models that can be probed with these techniques as well as projections for current and near-term noble liquid, semiconductor, and scintillator experiments. Finally, I will discuss some new techniques that may allow us to more robustly discriminate between dark matter signatures and background.

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## Gamma-ray Constraints on Decaying Dark Matter and Implications for IceCube

Tuesday Mar 28, 2017
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Utilizing the Fermi measurement of the gamma-ray spectrum toward the Galactic Center, we derive some of the strongest constraints to date on the dark matter (DM) lifetime in the mass range from hundreds of MeV to above an EeV. Our profile-likelihood based analysis relies on 413 weeks of Fermi Pass 8 data from 200 MeV to 2 TeV, along with up-to-date models for diffuse gamma-ray emission within the Milky Way.

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## Bounding Milli-magnetic charged particles

Tuesday Mar 14, 2017
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Just like how milli-electric charged particles can exist, so can milli-magnetic charged particles.  We review simple ways of evading the standard quantization arguments and why there are no model independent constraints on magnetically charged particles, milli-charged or not.  We then provide the first ever model independent bounds coming from magnetar cooling arguments.

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## Relaxion from particle production

Tuesday Mar 07, 2017

Recently a new solution to the hierarchy problem was proposed which makes use of the cosmological evolution of a light scalar field, a scanner, instead of symmetry or anthropic arguments to select a small Higgs mass. In the original proposal this scanner field could be the QCD axion and thus such class of solution became known as relaxion’’. Two central features required of the relaxion are a reason for why a small Higgs mass is special from the scanner’s viewpoint and a mechanism fo the scanner to dissipate its energy in order to stop in a value associated with small Higgs mass.

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## Goldstone Boson Counting in the Presence of Space-Time Symmetry Breaking, Non-Derivative Couplings and non-Fermi Liquid Behavior

Tuesday Feb 14, 2017
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## Radioactive Iron Rain: Evidence of a Recent Nearby Supernova Explosion

Tuesday Feb 07, 2017
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A very close supernova explosion could have caused a mass extinction

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## Coulomb artifacts and matching in lattice NRQCD;

Friday Feb 03, 2017
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## Cores in Dwarf Galaxies from Fermi Repulsion

Tuesday Jan 31, 2017
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Cold dark matter provides a remarkably good description of cosmology and astrophysics. However, observations connected with small scales might be in tension with this framework. In particular, structure formation simulations suggest that the density profiles of dwarf spheroidal galaxies should exhibit cusps, in contrast to observations.

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## RECENT PUBLIC LECTURE

### Rob Moore: Stanford Institute for Materials and Energy Sciences

Speaker: Rob Moore