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.


Tuesday Nov 12, 2013

We propose a robust, unified framework, in which the similar baryon and dark matter cosmic abundances both arise from the physics of weakly interacting massive particles (WIMPs), with the rough quantitative success of the so-called “WIMP miracle”. In particular the baryon asymmetry arises from the decay of a meta-stable WIMP after its thermal freezeout at or below the weak scale. A minimal model and its embedding in R-parity violating (RPV) natural SUSY are studied as examples. The new mechanism saves RPV SUSY from the potential crisis of washing out primordial baryon asymmetry.

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Tuesday Nov 05, 2013

I'll discuss a class of supersymmetric models in
which the physical Higgs mass is freed from the quartic coupling, thereby
allowing for a 125 GeV Higgs state whose self-interaction can be much smaller
than in the SM via a mechanism of 'induced EWSB'. This class of models
provides a unique alternative to other realizations of natural SUSY, and the
simplest realizations necessitate additional characteristic scalars below the
TeV scale, thus altering phenomenological predictions for additional Higgses at
the LHC.

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Friday Nov 01, 2013


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Tuesday Oct 29, 2013

We will discuss the renormalization group flow
between different classes of CFTs in four dimensions and study possible lower
bounds on the "distances" between these theories.

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Friday Oct 18, 2013

particle expansions, familiar from heavy quark physics, have found important
applications in the analysis of dark matter candidates and their interactions
with the Standard Model. From a different direction, precision
spectroscopy of muonic hydrogen has challenged QED and required more precise
knowledge of proton structure. These problems have forced a closer
examination of the construction of general heavy particle lagrangians at high
orders in the 1/M expansion, and in the absence of known ultraviolet

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Tuesday Oct 15, 2013

Searches for physics beyond the standard model come in
many forms, from terrestrial probes to astroparticle experiments and
cosmological observations. Efforts to
combine multiple search channels in 'global fits' to new physics scenarios
typically consider only a subset of the available channels. Astroparticle searches in particular are
usually only included in a very approximate way, if at all. In this talk I will review recent progress in
including detailed gamma-ray, neutrino and CMB searches for dark matter in

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Tuesday Sep 24, 2013

We propose a simple renormalizable
model of baryogenesis and asymmetric dark matter generation at the electroweak
phase transition. Our setup utilizes the two Higgs doublet model plus two
complex gauge singlets, the lighter of which is stable dark matter. The dark
matter is charged under a global symmetry that is broken in the early universe
but restored during the electroweak phase transition. Because the ratio of
baryon and dark matter asymmetries is controlled by model parameters, the dark

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Friday Sep 06, 2013

The local Callan-Symanzik equation
describes the response of a quantum field theory to local scale transformations
in the presence of background sources. The consistency conditions associated
with this anomalous equation can be used to derive powerful constraints on RG
flows. We will discuss various aspects of the equation and present new results
regarding the structure of the anomaly. We then use the equation to write
correlation functions of the trace of the energy-momentum tensor

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Tuesday Aug 27, 2013

We study the naturalness problem using a model
independent bottom up approach by considering models where only the interaction
terms needed to cancel the Higgs quadratic divergences are present. If
quadratic divergences are canceled by terms linear in the Higgs field, then the
collider phenomenology is well covered by current electroweakino and fourth
generation searches. If quadratic divergences are canceled by terms bilinear in
the Higgs field, then the signatures are highly dependent on the quantum

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Tuesday Jul 09, 2013

We consider the production of strongly interacting, heavy SUSY pairs at the LHC. When the centre of mass energy is close to the production threshold of the pair, the corresponding cross sections receive large higher-loop QCD corrections. These corrections are classified as the so-called soft logarithms and Coulomb singularities and they lead to a break down of the usual perturbation expansion. In this talk I review the origin of these large corrections and explain how they can be resummed by using Effective Field theories.

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