This series consists of talks in the areas of Particle Physics, High Energy Physics & Quantum Field Theory.
We derive constraints on the sign of couplings in an effective Higgs Lagrangian using prime principles such as the naturalness principle, global symmetries, and unitarity. Specifically, we study four dimension-six operators, O_H, O_y, O_g, and O_gamma, which contribute to the production and decay of the Higgs boson at the Large Hadron Collider (LHC), among other things.
In generalized models of gauge-mediated supersymmetry breaking, a standard model-like Higgs boson can decay to pairs of neutralino superpartners. If the energy scale of supersymmetry breaking is very low, each of these neutralinos will subsequently decay promptly to a photon and a gravitino. This process gives rise to a collider signal consisting of a pair of photons and missing energy.
The calculation of soft supersymmery breaking terms type IIB string theoretic models is discussed. Both classical and quantum contributions are evaluated. The suppression of FCNC gives a lower bound on the size of the compactification volume. Essentially what is obtained is a sequestered theory with the dominant pattern of soft masses and gaugino masses being that expected from AMSB and gaugino mediation with a gravitino mass around 100TeV.
We present a short review of the local conformal symmetry and its anomalous violation in curved $4d$ space-time. Furthermore we discuss the ambiguities of conformal anomaly and the anomaly-induced effective actions. Despite the conformal symmetry is always broken at quantum level, it is useful for constructing the best known approximations for investigating quantum corrections to the classical action of gravity. These quantum corrections represent an appropriate basis for a number of applications in cosmology and black hole physics.
We use black holes to understand some basic properties of theories of quantum gravity. First, we apply ideas from black hole physics to the physics of accelerated observers to show that the equations of motion of generalized theories of gravity are equivalent to the thermodynamic relation $\delta Q = T \delta S$. Our proof relies on extending previous arguments by using a more general definition of the Noether charge entropy. We have thus completed the implementation of Jacobson's proposal to express Einstein's equations as a thermodynamic equation of state.
The screening of electric charge in plasma with Bose condensate of a charged scalar field is calculated. In all previous calculations before 2009 the effects of Bose condensation have not been considered. Due to the condensate the time-time component of the photon polarization tensor in addition to the usual terms k-squared and Debye mass squared, contains infrared singular terms inversely proportional to k and k-squared. Such terms lead to power law oscillation behaviour of the screened potential, which is different form Friedel oscillations known for fermions.
The relic neutrino background contains a gapless, spin-2 sound mode, as well as a spin-1 mode if there is a neutrino-antineutrino asymmetry. The self-coupling of the spin-2 mode is given by Z boson exchange in the Standard Model and is parametrically similar to Newton's constant given the expected density of relic neutrinos. I will describe this emergent gravity theory and also describe how emergent theories avoid the Weinberg-Witten theorem, when the constituent degrees of freedom live in a flat Lorentz invariant space.
The particle physics community is bubbling with excitement since the recent discovery in the cosmic radiation of a positron and electron excess at high energy. This may be the first indirect hint that dark matter particles wander in the halo of the Milky Way. However, these species do not seem to have the expected properties. I will review the various pieces of that puzzle and present a status report of the current developments in that fast moving field.
It is well known that new physics at the electroweak scale could solve important puzzles in cosmology, such as the nature of dark matter and the origin of the cosmic baryon asymmetry. In this talk, I discuss some of the simplest, non-supersymmetric possibilities, their collider signatures, and the prospects for their discovery and identification at the LHC.
In this talk I describe the progress that we have made in the constuction of string vacua with many of the features of the minimal supersymmetric standard model (MSSM).