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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.


Vendredi 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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Mardi 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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Mardi 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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Vendredi 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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Mardi aoû 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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Mardi juil 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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Mardi avr 30, 2013

In this talk, I will start with
briefly introducing some universal physics behind quantum hall and topological
insulator , which inspired a BSM flavor model. It intimately relates
deconstructed little Higgs to flavor structure: fermion masses, CKM etc.
 This new cousin of little Higgs, we call it little flavor, shares a 10-20
Tev cut-off scale with little Higgs, so as to explain flavor structure at
surprisingly low scale without rising FCNC problem.

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Mardi avr 02, 2013

is at a crossroad that leads either to Naturalness or the Multiverse. While the
confirmation of gauge coupling unification in the early 90s gave a tremendous
boost to naturalness and to low energy SUSY, the lack of evidence
for new physics beyond the standard model at the LHC points to a paucity of new
particles near the weak scale. This suggests that the weak scale is tuned and
that supersymmetry, if present at all, is realized at higher energies. This

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Mardi mar 26, 2013

I introduce a new
nonrelativistic effective field theory which systematically accounts for the finite lifetime effects in production of unstable

The theory is applied to the threshold production of top quark-antiquark

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Mardi mar 19, 2013

The Standard Model Higgs boson may be mixed
with another scalar that does not couple singly to gauge bosons or fermions.
The electroweak quantum numbers of such an additional scalar can be determined
by measuring the quartic Higgs-Higgs-vector-vector couplings, which
contribute—along with the coveted triple Higgs coupling—to double Higgs
production in e+e− collisions. We show that simultaneous sensitivity
to the quartic Higgs-Higgs-vector-vector coupling and the triple Higgs coupling

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