Particle Physics

Displaying 313 - 324 of 491

Asymmetric Dark Matter Bound States

Mark Wise California Institute of Technology (Caltech)

September 02, 2014

PIRSA:14090068
Coloron-assisted Leptoquarks at the LHC

Joshua Berger Cornell University
August 29, 2014

PIRSA:14080042
Particle Physics
Testing QED with positronium state

Alexander Penin University of Alberta
August 26, 2014

PIRSA:14080038
Particle Physics
Asymmetric Hawking Radiation : Baryogenesis from Hawking Radiation

Anson Hook University of Maryland, College Park
July 29, 2014

PIRSA:14070019
Particle Physics
Improving Mass Measurements Using Many-Body Phase Space

Can Kilic The University of Texas at Austin
July 15, 2014

PIRSA:14070023
Particle Physics
What Can We Learn from Precision Higgs

Maxim Perelstein Cornell University
June 13, 2014

PIRSA:14060003
Particle Physics
Are the recent IceCube events hinting at O(100) TeV decaying dark matter?

Atri Bhattacharya University of Liège
May 22, 2014

PIRSA:14050118
Particle Physics
New strong interactions and the t t-bar asymmetry

Joachim Brod University of Cincinnati
May 13, 2014

PIRSA:14050092
Particle Physics
Noncommutative geometry and the symmetries of the standard model

Fedele Lizzi University of Naples Federico II
May 06, 2014

PIRSA:14050031
Particle Physics

Cosmology
Boson Tagging with Wavelets

William Shepherd University of California, Santa Cruz
April 15, 2014

PIRSA:14040063
Particle Physics
GeV Gamma-Rays from the Central Milky Way and the Case for Annihilating Dark Matter

Tracy Slatyer Massachusetts Institute of Technology (MIT) - Department of Physics
March 26, 2014

PIRSA:14030120
Particle Physics
Naturalness and the Weak Gravity Conjecture

Clifford Cheung California Institute of Technology (Caltech) - Physics Office
March 25, 2014

PIRSA:14030119
Particle Physics

Asymmetric Dark Matter Bound States

Mark Wise California Institute of Technology (Caltech)

September 02, 2014

PIRSA:14090068

One of the simplest low energy effective theories with Asymmetric Dark Matter contains a gauge singlet Dirac Fermion for the dark matter and a gauge singlet scalar as the mediator that the dark matter decays into. In this model I discuss the spectrum of bound states (two body and multi-body) and the cosmological production/dissociation of dark matter two body bound states.
Coloron-assisted Leptoquarks at the LHC

Joshua Berger Cornell University
August 29, 2014

PIRSA:14080042
Particle Physics
Recent searches for a first-generation leptoquark by the CMS collaboration have shown around 2.5 sigma deviations from Standard Model predictions in both the eejj and e nu jj channels. Furthermore, the eejj invariant mass distribution has another 2.8 sigma excess from the CMS right-handed W plus heavy neutrino search. We point out that additional leptoquark production from a heavy coloron decay can provide a good explanation for all three excesses. The coloron has a mass around 2.1 TeV and the leptoquark mass can vary from 550 GeV to 650 GeV. A key prediction of this model is an edge in the total m_T distribution of e nu jj events at around 2.1 TeV.
Testing QED with positronium state

Alexander Penin University of Alberta
August 26, 2014

PIRSA:14080038
Particle Physics
The theory of quantum electrodynamics is recognized for the most accurate predictions in physics confirmed by experiment. I review the recent results on high precision tests of QED with an emphasize on the study of the positronium bound state.
Asymmetric Hawking Radiation : Baryogenesis from Hawking Radiation

Anson Hook University of Maryland, College Park
July 29, 2014

PIRSA:14070019
Particle Physics
We show that in the presence of a chemical potential, black hole evaporation generates baryon number. If the inflaton or Ricci scalar is derivatively coupled to the B-L current, the expansion of the universe acts as a chemical potential and splits the energy levels of particles and their anti-particles. The asymmetric Hawking radiation of primordial black holes can thus be used to generate a B-L asymmetry. If dark matter is produced by the same mechanism, the coincidence between the mass density of visible and dark matter can be naturally explained.
Improving Mass Measurements Using Many-Body Phase Space

Can Kilic The University of Texas at Austin
July 15, 2014

PIRSA:14070023
Particle Physics
After the 7 and 8 TeV LHC runs, we have no conclusive evidence of physics beyond the Standard Model, leading us to suspect that even if new physics is discovered during run II, the number of signal events may be limited, making it crucial to optimize measurements for the case of low statistics. I will argue that phase space correlations between subsequent on-shell decays in a cascade contain additional information compared to commonly used kinematic variables, and this can be used to significantly improve the precision and accuracy of mass measurements. The improvement is connected to the properties of the volume element of many-body phase space, and is particularly relevant to the case of low signal statistics.
What Can We Learn from Precision Higgs

Maxim Perelstein Cornell University
June 13, 2014

PIRSA:14060003
Particle Physics
In the coming years, LHC experiments will measure Higgs properties, such as its couplings, with increasing precision. Electron-positron Higgs factories, such as the ILC or TLEP, would be able to achieve even better precision. In this talk, I will discuss some of the physics questions that can be addressed by a precision Higgs coupling measurement program. First, the issue of naturalness of the electroweak scale can be addressed in a robust, model-independent manner. Second, the possibility of a first-order electroweak phase transition can be definitively probed, testing one of the necessary conditions of electroweak baryogenesis scenario.
Are the recent IceCube events hinting at O(100) TeV decaying dark matter?

Atri Bhattacharya University of Liège
May 22, 2014

PIRSA:14050118
Particle Physics
The IceCube detector has recently reported the observation of 28 events at previously unexplored energies. While the statistics of the observed events are still low, these events hint at the existence of a neutrino flux over and above the atmospheric neutrino background. We investigate the possibility that a significant component of the additional neutrino flux originates due to the decay of a very heavy dark matter (VHDM) particle via several possible channels into standard model particles. We show that a combination of a power law astrophysical neutrino spectrum and the neutrino flux from the decay of a DM species of mass in the range 150-400 TeV improves the fit to the observed neutrino events than that obtained from a best-fit astrophysical flux alone. Assuming the existence of an astrophysical background described by the IC best-fit, we also show that, for the decay of even heavier DM particles ($m_{\text{DM}} \sim 1$ PeV), the same observations impose significant constraints on the decay lifetimes. Allowing the astrophysical flux normalization to vary leads to modifications of these limits; however, there is still a range of dark matter mass and lifetime that is excluded by the IC results.
New strong interactions and the t t-bar asymmetry

Joachim Brod University of Cincinnati
May 13, 2014

PIRSA:14050092
Particle Physics
The CDF and D0 experiments at Tevatron measure a top-quark forward-backward
asymmetry significantly larger than the standard-model prediction.
We construct a model that involves new strong interactions at the electroweak scale
and can explain the measured asymmetry. Our model possesses a flavor symmetry
which allows to evade flavor and collider constraints, while it still permits flavor-violating
couplings of order 1 which are needed to generate the asymmetry via light t-channel vectors.
Noncommutative geometry and the symmetries of the standard model

Fedele Lizzi University of Naples Federico II
May 06, 2014

PIRSA:14050031
Particle Physics

Cosmology
I will describe Connes approach to the standard model based on spectral noncommutative geometry with particular emphasis on the symmetries. The model poses constraints which are satisfied by the standard model group, and does not leave much room for other possibilities. There is however a possibility for a larger symmetry (the ``grand algebra'') which may also be instrumental to obtain the correct mass of the Higgs.
Boson Tagging with Wavelets

William Shepherd University of California, Santa Cruz
April 15, 2014

PIRSA:14040063
Particle Physics
I'll present a proof-of-concept new technique for tagging boosted objects which decay into two colored particles based on the wavelet transform. It is able to moderately improve the sensitivity of searches for such particles by 6-7%. I will also discuss future directions of applicability.
GeV Gamma-Rays from the Central Milky Way and the Case for Annihilating Dark Matter

Tracy Slatyer Massachusetts Institute of Technology (MIT) - Department of Physics
March 26, 2014

PIRSA:14030120
Particle Physics
Past studies have identified a spatially extended excess of ~1-3 GeV gamma rays from the Galactic Center and inner Galaxy, consistent with the emission expected from annihilating thermal relic dark matter. I will describe recent improvements in the characterization of this signal, which demonstrate that it is spherically symmetric, centered on the Galactic Center, and with a spatial profile consistent with annihilation from a cusped NFW profile. The excess can be detected out to 10 degrees from the Galactic Center, which poses challenges for a millisecond pulsar origin; I will discuss the implications of a dark matter interpretation.
Naturalness and the Weak Gravity Conjecture

Clifford Cheung California Institute of Technology (Caltech) - Physics Office
March 25, 2014

PIRSA:14030119
Particle Physics
The weak gravity conjecture (WGC) asserts a powerful consistency condition on gauge theories coupled to quantum gravity: an Abelian, long-range force requires a state of charge q and mass m such that q > m/mPl. Failure of this condition implies the existence of stable black hole remnants and is in tension with no-hair theorems. In this paper, we argue that the WGC creates a non- perturbative obstruction to naturalness, which is the notion that dimensionless coefficients should take on O(1) values in the absence of enhanced symmetry. As an illustration, we show that for scalar quantum electrodynamics, a natural spectrum can actually be forbidden by the WGC, which bounds a radiatively unstable quantity, m, by a radiatively stable quantity, q. More generally, the WGC can be at odds with naturalness in any theory containing charged fundamental scalars. We extend the conditions of the WGC to more complicated theories with multiple gauge symmetries and particles. Finally, we discuss implications for the hierarchy problem and construct a simple model in which the natural value of the electroweak scale—at the cutoff—is forbidden by the WGC.

Title	Speaker(s)	Date	Talk Type	Info
Asymmetric Dark Matter Bound States	Mark Wise	2014-09-02	Scientific Series	View details
Coloron-assisted Leptoquarks at the LHC	Joshua Berger	2014-08-29	Scientific Series	View details
Testing QED with positronium state	Alexander Penin	2014-08-26	Scientific Series	View details
Asymmetric Hawking Radiation : Baryogenesis from Hawking Radiation	Anson Hook	2014-07-29	Scientific Series	View details
Improving Mass Measurements Using Many-Body Phase Space	Can Kilic	2014-07-15	Scientific Series	View details
What Can We Learn from Precision Higgs	Maxim Perelstein	2014-06-13	Scientific Series	View details
Are the recent IceCube events hinting at O(100) TeV decaying dark matter?	Atri Bhattacharya	2014-05-22	Scientific Series	View details
New strong interactions and the t t-bar asymmetry	Joachim Brod	2014-05-13	Scientific Series	View details
Noncommutative geometry and the symmetries of the standard model	Fedele Lizzi	2014-05-06	Scientific Series	View details
Boson Tagging with Wavelets	William Shepherd	2014-04-15	Scientific Series	View details
GeV Gamma-Rays from the Central Milky Way and the Case for Annihilating Dark Matter	Tracy Slatyer	2014-03-26	Scientific Series	View details
Naturalness and the Weak Gravity Conjecture	Clifford Cheung	2014-03-25	Scientific Series	View details

Particle Physics

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