A5071883428- Particle physics theoretical and experimental studies
- Black Holes and Theoretical Physics
- Cosmology and Gravitation Theories
- Quantum Chromodynamics and Particle Interactions
- Dark Matter and Cosmic Phenomena
- Computational Physics and Python Applications
- High-Energy Particle Collisions Research
- Quantum Mechanics and Applications
- Relativity and Gravitational Theory
- Noncommutative and Quantum Gravity Theories
- Neutrino Physics Research
- Atomic and Subatomic Physics Research
- Cold Atom Physics and Bose-Einstein Condensates
- Pulsars and Gravitational Waves Research
- Quantum, superfluid, helium dynamics
- Astrophysics and Cosmic Phenomena
- Quantum Electrodynamics and Casimir Effect
- Quantum Information and Cryptography
- Superconducting Materials and Applications
- Nonlinear Waves and Solitons
- Quantum Computing Algorithms and Architecture
- Advanced Thermodynamics and Statistical Mechanics
- Space Science and Extraterrestrial Life
- Particle Detector Development and Performance
- Biofield Effects and Biophysics
University of California, Davis
2015-2024
Cornell University
2016
University of California System
2013-2015
European Organization for Nuclear Research
2010-2011
Massachusetts Institute of Technology
2008
Los Alamos National Laboratory
2002-2005
University of California, Irvine
2004
Harvard University
2000-2001
University of Maryland, College Park
2001
Lawrence Berkeley National Laboratory
1998-2000
We analyze the cosmology of Randall-Sundrum model and that compact brane models in general presence a radius stabilization mechanism. find expansion our Universe is generically agreement with expected effective four dimensional description. The constraint (which responsible for appearance nonconventional cosmologies these models) must be imposed on matter densities two branes theory without stabilized consequence requiring static solution even absence stabilization. Such constraints...
We consider extra dimensional gauge theories on an interval. first review the derivation of consistent boundary conditions (BC's) from action principle. These BC's include choices that give rise to breaking symmetries. The could be chosen coincide with those commonly applied in orbifold theories, but there are many more possibilities. To investigate nature symmetry via we calculate elastic scattering amplitudes for longitudinal bosons. find using a set terms these explicitly grow energy...
We present a 5D gauge theory in warped space based on bulk $\mathrm{SU}(2{)}_{L}\ifmmode\times\else\texttimes\fi{}\mathrm{SU}(2{)}_{R}\ifmmode\times\else\texttimes\fi{}\mathrm{U}(1{)}_{B\ensuremath{-}L}$ group where the symmetry is broken by boundary conditions. The breaking pattern and mass spectrum resemble that standard model (SM). To leading order warp factor $\ensuremath{\rho}$ parameter coupling of $Z$ ($S$ parameter) are as SM, while corrections expected at level percent. From...
This biennial Review summarizes much of Particle Physics. Using data from previous editions, plus 2205 new measurements 667 papers, we list, evaluate, and average measured properties gauge bosons, leptons, quarks, mesons, baryons. We also summarize searches for hypothetical particles such as Higgs heavy neutrinos, supersymmetric particles. All the particle search limits are listed in Summary Tables. give numerous tables, figures, formulae, reviews topics Standard Model, detectors,...
We calculate the tree-level expressions for electroweak precision observables in $\mathrm{SU}(5)/SO(5)$ littlest Higgs model. The source these corrections are exchange of heavy gauge bosons and a triplet vacuum expectation value (VEV). Weak isospin violating contributions present because there is no custodial $\mathrm{SU}(2)$ global symmetry. bulk weak arise from boson while smaller contribution comes VEV. A fit performed to experimental data we find that throughout parameter space symmetry...
We calculate the tree-level electroweak precision constraints on a wide class of little Higgs models including: variations Littlest SU(5)/SO(5), SU(6)/Sp(6), and SU(4)^4/SU(3)^4. By performing global fit to data we find that for generic regions parameter space bound symmetry breaking scale f is several TeV, where have kept normalization constant in different models. For example, ``minimal'' implementation SU(6)/Sp(6) bounded by f>3.0 TeV throughout most space, SU(4)^4/SU(3)^4 f^2 =...
We investigate the zero temperature chiral phase transition in an $\mathrm{SU}(N)$ gauge theory as number of fermions ${N}_{f}$ is varied. argue that there exists a critical ${N}_{f}^{c}$, above which no symmetry breaking or confinement, and below both confinement set in. estimate ${N}_{f}^{c}$ discuss nature transition.
We present a simple model where photons propagating in extragalactic magnetic fields can oscillate into very light axions. The oscillations may convert some of the photons, departing distant supernova, axions, making supernova appear dimmer and hence more than it really is. Averaging over different configurations field we find that dimming saturates at about one-third from supernovae large redshifts. This results luminosity distance versus redshift curve almost indistinguishable produced by...
We consider fermions on an extra dimensional interval. find the boundary conditions at ends of interval that are consistent with variational principle, and explain which ones arise in various physical circumstances. apply these results to Higgsless models electroweak symmetry breaking, where is not broken by a scalar vacuum expectation value, but rather gauge fields. show it possible set for bulk would give realistic fermion mass spectrum without presence Higgs scalar, present some sample...
We consider various constraints on Higgsless models of electroweak symmetry breaking based a bulk SU(2)_L x SU(2)_R U(1)_{B-L} gauge group in warped space. First we show that the S parameter which is positive if fermions are localized Planck brane can be lowered (or made vanishing) by changing localization light fermions. If wave function almost flat their coupling to boson KK modes will close vanishing, and therefore contributions suppressed. At same time experimental bounds such Z' W'...
We propose a new dark matter candidate, ``quirky matter,'' that is scalar baryonic bound state of non-Abelian force becomes strong below the electroweak scale. The made chiral quirks: fermions transform under both as well in representation group, acquiring mass from Higgs mechanism. Electric charge neutrality lightest baryon requires approximately degenerate quirk masses which also causes radius to be negligible. abundance determined by an asymmetry linked and lepton numbers universe through...
We consider the phenomenology of a resonance that couples to photons but not gluons, and estimate its production rate at LHC from photon-photon fusion in elastic pp scattering using effective photon narrow width approximations. The is sensitive only mass, spin, total resonance, branching fraction photons. Production cross sections 5-10 fb 13 TeV can be easily accommodated for 750 GeV with partial 15 GeV. This provides minimal explanation reported diphoton anomaly early Run II data.
We consider the two-brane Randall-Sundrum (RS) model with bulk gauge fields. carefully match theory to a 4D low-energy effective Lagrangian. In addition four-fermion operators induced by KK exchange we find that large negative S and T parameters are in theory. This is tree-level effect consequence of shapes W Z wave functions bulk. Such effects generic extra dimensional theories where standard (SM) bosons have non-uniform along dimension. The corrections precision electroweak observables RS...
We investigate the chiral phase transition in $\mathrm{SU}(N)$ gauge theories as number of quark flavors, ${N}_{f},$ is varied. argue that takes place at a large enough value ${N}_{f}$ so it governed by infrared fixed point \ensuremath{\beta} function. study nature analytically and numerically, discuss spectrum theory critical approached both symmetric broken phases. Since conformal point, there are no light excitations on side. extend previous work to include higher order effects developing...
We describe a method for introducing gauge fields into nonlocal Lagrangians, and deriving the resulting Feynman rules. The is applied in detail to chiral quark model. In particular we how calculate coupling constants of effective Lagrangian that results when quarks are integrated out theory.