A5110239166- Particle physics theoretical and experimental studies
- Cosmology and Gravitation Theories
- Black Holes and Theoretical Physics
- Dark Matter and Cosmic Phenomena
- Quantum Chromodynamics and Particle Interactions
- Atomic and Subatomic Physics Research
- Neutrino Physics Research
- Computational Physics and Python Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Quantum and electron transport phenomena
- Galaxies: Formation, Evolution, Phenomena
- Physics of Superconductivity and Magnetism
- Astrophysics and Cosmic Phenomena
- Noncommutative and Quantum Gravity Theories
- Advanced Frequency and Time Standards
- High-Energy Particle Collisions Research
- Quantum, superfluid, helium dynamics
- Astrophysical Phenomena and Observations
- Quantum Electrodynamics and Casimir Effect
- Pulsars and Gravitational Waves Research
- Relativity and Gravitational Theory
- Quantum Mechanics and Applications
- Quantum many-body systems
- Theoretical and Computational Physics
- Geometric and Algebraic Topology
University of Oxford
2013-2024
Fermi National Accelerator Laboratory
2016
Stanford University
2001-2015
University of California, Davis
2006
University of California, Irvine
2004
European Organization for Nuclear Research
1998-2003
University of California, Berkeley
2001-2002
Institute for Advanced Study
1995-1999
Lawrence Berkeley National Laboratory
1994-1995
Princeton University
1991-1992
String theory suggests the simultaneous presence of many ultralight axions possibly populating each decade mass down to Hubble scale 10^-33eV. Conversely such a plenitude (an "axiverse") would be evidence for string theory, since it arises due topological complexity extra-dimensional manifold and is ad hoc in with just four familiar dimensions. We investigate how upcoming astrophysical experiments will explore existence over vast range from 10^-33eV 10^-10eV. Axions masses between 10^-28eV...
We propose an alternate, calculable mechanism of dark matter genesis, "thermal freeze-in," involving a Feebly Interacting Massive Particle (FIMP) interacting so feebly with the thermal bath that it never attains equilibrium. As conventional freeze-out" production mechanism, relic abundance reflects combination initial distributions together particle masses and couplings can be measured in laboratory or astrophysically. The freeze-in yield is IR dominated by low temperatures near FIMP mass...
Recently it was proposed that the standard model (SM) degrees of freedom reside on a $(3+1)$-dimensional wall or ``3-brane'' embedded in higher-dimensional spacetime. Furthermore, this picture is possible for fundamental Planck mass $\mst$ to be as small weak scale $\mst\simeq O(\tev)$ and observed weakness gravity at long distances due existence new sub-millimeter spatial dimensions. We show natural expect neutrino masses occur $10^{-1} - 10^{-4}\ev$ range, despite lack any higher than...
Recently, a new framework for solving the hierarchy problem was proposed which does not rely on low energy supersymmetry or technicolor. The fundamental Planck mass is at TeV and observed weakness of gravity long distances due existence sub-millimeter spatial dimensions. In this letter, we study how properties black holes are altered in these theories. Small holes—with Schwarzschild radii smaller than size dimensions—are quite different. They bigger, colder, longer-lived usual...
We present the report of hadronic working group BOOST2010 workshop held at University Oxford in June 2010. The first part contains a review potential decays highly boosted particles as an aid for discovery LHC and discussion status tools developed to meet challenge reconstructing isolating these topologies. In second part, we new results comparing performance jet grooming techniques top tagging algorithms on common set benchmark channels. also study sensitivity substructure observables...
We outline the experimental concept and key scientific capabilities of AION (Atom Interferometer Observatory Network), a proposed programme using cold strontium atoms to search for ultra-light dark matter, explore gravitational waves in mid-frequency range between peak sensitivities LISA LIGO/Virgo/ KAGRA/INDIGO/Einstein Telescope/Cosmic Explorer experiments, probe other frontiers fundamental physics. would complement planned searches as well mergers involving intermediate-mass black holes...
MAGIS-100 is a next-generation quantum sensor under construction at Fermilab that aims to explore fundamental physics with atom interferometry over 100-meter baseline. This novel detector will search for ultralight dark matter, test mechanics in new regimes, and serve as technology pathfinder future gravitational wave detectors previously unexplored frequency band. It combines techniques demonstrated state-of-the-art 10-meter-scale interferometers the latest technological advances of world's...
We discuss experimental implications of extending the gauge structure standard model to include an additional $U(1)$ interaction broken at or near weak scale. work with most general, renormalizable Lagrangian for $\mathrm{SU}(2)\ifmmode\times\else\texttimes\fi{}U(1)\ifmmode\times\else\texttimes\fi{}U(1)$ sector, emphasis on phenomenon kinetic mixing between two fields, and do not restrict ourselves any ``canonical'' ${Z}^{\ensuremath{'}}$ models often discussed in literature. Low-energy...
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,...
In this paper, we investigate the possibility of explaining both ${R}_{b}$ excess and ${R}_{c}$ deficit reported by CERN LEP experiments through $Z\ensuremath{-}{Z}^{\ensuremath{'}}$ mixing effects. We have constructed a set models consistent with restrictive principles: unification standard model (SM) gauge couplings, vector-like additional matter, couplings which are generation independent leptophobic. These anomaly-free, perturbative up to GUT scale, contain realistic mass spectra. Out...
The inferred values of the cosmological baryon and dark matter densities are strikingly similar, but in most theories early universe there is no true explanation this fact; particular, asymmetry thus density depends upon unknown, {\it a priori} unknown possibly small, CP-violating phases which independent all parameters determining density. We consider models possessing particle-antiparticle where determines both strongly effects density, naturally linking $\Omega_{\rm{b}}$...
We argue that WIMP dark matter can annihilate via long-lived "WIMPonium" bound states in reasonable particle physics models of (DM). WIMPonium occur at or near threshold leading to substantial enhancements the DM annihilation rate, closely related Sommerfeld effect. Large "boost factor" amplifications rate thus without large density enhancements, possibly preferring colder less dense objects such as dwarf galaxies locations for indirect searches. The radiative capture and transitions among...
In the context of brane-world theories, production cross-section for black holes may be greatly enhanced. Such can in principle lead to detectable signals via their Hawking evaporation brane-localized modes. We calculate, semiclassical approximation, leading corrections energy spectrum (the greybody factors) decay into scalar fields, as a function number toroidally compactified extra dimensions, and partial wave number.
We consider some observable consequences of the possible breaking discrete space-time symmetries $P$ and $T$ in high-${T}_{c}$ superconducting materials, as occurs anyon models. It is argued, within these models, that at least two species anyons are expected to occur, a result quasimagnetic modification algebra translations. find there an intrinsic orbital magnetic moment perpendicular each layer, whose sign depends on broken symmetry layer. If coupling between layers ferromagnetic, should...
We present a purely gravitational infra-red-calculable production mechanism for dark matter (DM) . The source of both the DM relic abundance and hot Standard Model (SM) plasma is primordial density micro black holes (BHs), which evaporate via Hawking emission into SM sectors. has four qualitatively different regimes depending upon whether BH evaporation 'fast' or 'slow' relative to initial Hubble rate, mass particle 'light' 'heavy' compared temperature. For each these we calculate yield, Y,...
Dark matter (DM) without a asymmetry is studied in the context of twin Higgs (TH) theories which LHC naturalness problem addressed. These possess sector related to Standard Model (SM) by (broken) ${\mathbb{Z}}_{2}$ symmetry, and interacting with SM via specific portal. We focus on minimal realization TH mechanism, fraternal Higgs, only single generation quarks leptons, $SU(3{)}^{\ensuremath{'}}\ifmmode\times\else\texttimes\fi{}SU(2{)}^{\ensuremath{'}}$ gauge group. show that variety natural...
We study asymmetric dark matter (ADM) in the context of minimal (fraternal) twin Higgs solution to little hierarchy problem, with a sector gauged $SU(3{)}^{\ensuremath{'}}\ifmmode\times\else\texttimes\fi{}SU(2{)}^{\ensuremath{'}}$, doublet, and only third-generation fermions. Naturalness requires ${\mathrm{QCD}}^{\ensuremath{'}}$ scale ${\mathrm{\ensuremath{\Lambda}}}_{\mathrm{QCD}}^{\ensuremath{'}}\ensuremath{\simeq}0.5--20\text{ }\text{ }\mathrm{GeV}$, that ${t}^{\ensuremath{'}}$ is heavy....
Abstract Any new vector boson with non-zero mass (a 'dark photon' or 'Proca boson') that is present during inflation automatically produced at this time from vacuum fluctuations and can comprise all a substantial fraction of the observed dark matter density, as shown by Graham, Mardon, Rajendran. We demonstrate, utilising both analytic numerical studies, such scenario implies an extremely rich substructure arising purely interplay gravitational interactions quantum effects. Due to remarkable...
We reconsider theories with low gravitational (or string) scale ${M}_{*}$ where Newton's constant is generated via new large-volume spatial dimensions, while standard model states are localized to a 3-brane. Utilizing compact hyperbolic manifolds we show that the spectrum of Kaluza-Klein modes radically altered. This allows early Universe evolve normally up substantial temperatures, and completely negates astrophysical constraints on ${M}_{*}$. Furthermore, an exponential hierarchy between...