Particle Physics

Particle physics is the science which identifies nature's constituents and interactions at the most fundamental level, with an emphasis on comparing theoretical ideas with both terrestrial experiments and astrophysical observations. This mandate gives it a strong overlap with string theory, quantum gravity and cosmology. Particle physicists at Perimeter Institute are currently involved in identifying how cosmological observations and terrestrial accelerator and underground experiments constrain the theoretical possibilities for physics beyond the Standard Model.

Displaying 697 - 708 of 1429

Cosmological Collider Physics

Nima Arkani-Hamed Institute for Advanced Study (IAS)
November 06, 2014

PIRSA:14110115
Particle Physics
Higgs Physics with the ATLAS experiment

Pierre Savard University of Toronto
October 31, 2014

PIRSA:14100120
Particle Physics
Discovering the QCD Axion with Black Holes and Gravitational Waves

Masha Baryakhtar University of Washington
October 28, 2014

PIRSA:14100049
Particle Physics
De Sitter Wavefunctionals and the Resummation of Time

Matthew Baumgart Carnegie Mellon University
October 07, 2014

PIRSA:14100051
Particle Physics
ADMX: The Axion Dark Matter Experiment

Gray Rybka University of Washington
September 30, 2014

PIRSA:14090067
Particle Physics
Scalar Simplified Models and Dark Matter at Colliders

Matthew Buckley Rutgers University
September 16, 2014

PIRSA:14090080
Particle Physics
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

Cosmological Collider Physics

Nima Arkani-Hamed Institute for Advanced Study (IAS)
November 06, 2014

PIRSA:14110115
Particle Physics
Higgs Physics with the ATLAS experiment

Pierre Savard University of Toronto
October 31, 2014

PIRSA:14100120
Particle Physics
An overview of the latest Higgs physics results from the ATLAS collaboration will be presented. Next year, the Large Hadron collider will restart at a higher collision energy after a 2-year shutdown. The Higgs physics programme for this next data taking period will be discussed.
Discovering the QCD Axion with Black Holes and Gravitational Waves

Masha Baryakhtar University of Washington
October 28, 2014

PIRSA:14100049
Particle Physics
In the next few years, Advanced LIGO will be the first experiment to detect gravitational waves. Through superradiance of stellar black holes, it may also be the first experiment to discover the QCD axion with decay constant around or above the GUT scale. When an axion's Compton wavelength is comparable to the size of a black hole, the axion binds to the black hole, forming a "gravitational atom". Due to superradiance, the number of axions occupying the bound levels grows exponentially, extracting energy and angular momentum from the black hole. I will discuss the promising gravitational wave signals from axions transitioning between levels of the gravitational atom and axions annihilating to gravitons. Events for axions in the range 10^−13 to 10^−10 eV can be visible at aLIGO. The signals produced are long-lasting, monochromatic, and can be distinguished from ordinary astrophysical sources. These signatures are also promising for lighter axions at future, lower-frequency, GW observatories. I will also present our updated exclusion on the QCD axion mass range of 6*10^−13 eV < ma < 1.5*10^−11 eV imposed by black hole spin measurements.
De Sitter Wavefunctionals and the Resummation of Time

Matthew Baumgart Carnegie Mellon University
October 07, 2014

PIRSA:14100051
Particle Physics
The holographic RG of Anti-De Sitter gives a powerful clue about the underlying AdS/CFT correspondence. The question is whether similar hints can be found for the heretofore elusive holographic dual of De Sitter. The framework of stochastic inflation uses nonperturbative insight to tame bad behavior in the perturbation series of a massless scalar in DS at late times. Remarkably, this fully quantum system loses phase information in the leading approximation, but retains a probabilistic character and allows for a controlled prediction of late time Green's functions. Recasting this as a "resummation of time", we wish understand whether the distributions that result can be thought of as an attractive UV fixed point of a theory
living on a spacelike slice of DS. We derive stochastic inflation via the wavefunctional approach to Quantum Field Theory. This allows for the straightforward implementation of corrections to the original framework.
ADMX: The Axion Dark Matter Experiment

Gray Rybka University of Washington
September 30, 2014

PIRSA:14090067
Particle Physics
Axions are an exceptionally well-motivated dark matter candidate in addition to being a consequence of the Peccei-Quinn solution to the strong CP problem. ADMX (Axion Dark Matter eXperiment) has recently been selected as the axion search for the US DOE Second-Generation Dark Matter Program. I will discuss the imminent upgrade of ADMX to a definitive search for micro-eV mass dark matter axions as well as the ongoing research and development of new technologies to expand the reach of ADMX to the entire plausible dark matter axion mass range.
Scalar Simplified Models and Dark Matter at Colliders

Matthew Buckley Rutgers University
September 16, 2014

PIRSA:14090080
Particle Physics
Dark matter is clear evidence of the existence of new physics beyond the Standard Model, and there are compelling reasons to expect that this physics can be probed at the LHC. As we prepare for Run II, we must consider a wide range of possible phenomenology, leaving no stone unturned. In this talk, I present a set of scalar and pseudoscalar models which provide a useful framework to interpret dark matter results, and can motivate new searches in novel channels at the LHC.
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.

Title	Speaker(s)	Date	Talk Type	Info link
Cosmological Collider Physics	Nima Arkani-Hamed	2014-11-06	Scientific Series	View details
Higgs Physics with the ATLAS experiment	Pierre Savard	2014-10-31	Scientific Series	View details
Discovering the QCD Axion with Black Holes and Gravitational Waves	Masha Baryakhtar	2014-10-28	Scientific Series	View details
De Sitter Wavefunctionals and the Resummation of Time	Matthew Baumgart	2014-10-07	Scientific Series	View details
ADMX: The Axion Dark Matter Experiment	Gray Rybka	2014-09-30	Scientific Series	View details
Scalar Simplified Models and Dark Matter at Colliders	Matthew Buckley	2014-09-16	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

Particle Physics

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