Paul Langacker
A5087686834- Particle physics theoretical and experimental studies
- Dark Matter and Cosmic Phenomena
- Quantum Chromodynamics and Particle Interactions
- Neutrino Physics Research
- Cosmology and Gravitation Theories
- Black Holes and Theoretical Physics
- Computational Physics and Python Applications
- Astrophysics and Cosmic Phenomena
- High-Energy Particle Collisions Research
- Complex Systems and Time Series Analysis
- Distributed and Parallel Computing Systems
- Particle Detector Development and Performance
- Quantum Mechanics and Applications
- Atomic and Subatomic Physics Research
- Nuclear Physics and Applications
- Solar and Space Plasma Dynamics
- International Science and Diplomacy
- Quantum, superfluid, helium dynamics
- Relativity and Gravitational Theory
- Particle Accelerators and Free-Electron Lasers
- Geophysics and Gravity Measurements
- Noncommutative and Quantum Gravity Theories
- Superconducting Materials and Applications
- Earth Systems and Cosmic Evolution
- Quantum Computing Algorithms and Architecture
Institute for Advanced Study
2007-2019
University of Pennsylvania
2001-2018
Northeastern University
2018
HUN-REN Wigner Research Centre for Physics
2017
Albert Einstein College of Medicine
2007-2016
Princeton University
2007-2016
RWTH Aachen University
2010
Universidad Nacional Autónoma de México
2010
Philadelphia University
1982-2008
Stanford University
1980-2004
This biennial Review summarizes much of particle physics. Using data from previous editions, plus 2658 new measurements 644 papers, we list, evaluate, and average measured properties gauge bosons, leptons, quarks, mesons, baryons. We summarize searches for hypothetical particles such as Higgs heavy neutrinos, supersymmetric particles. All the search limits are listed in Summary Tables. also give numerous tables, figures, formulae, reviews topics Standard Model, detectors, probability,...
The $\mathrm{U}{(1)}^{\ensuremath{'}}$ symmetry associated with a possible heavy ${Z}^{\ensuremath{'}}$ would have profound implications for particle physics and cosmology. motivations such particles in various extensions of the standard model, ranges their masses couplings, classes anomaly-free models are discussed. Present limits from electroweak collider experiments briefly surveyed, as prospects discovery diagnostic study at future colliders. Implications discussed, including an extended...
The implications of precision $Z$-pole, $W$-mass, and weak-neutral-current data for SU(2)\ifmmode\times\else\texttimes\fi{}U(1) models are described. Within the minimal model one finds ${{sin}^{2}\stackrel{^}{\ensuremath{\theta}}}_{W}({M}_{Z})=0.2334\ifmmode\pm\else\textpm\fi{}0.0008$ in modified subtraction scheme or ${{sin}^{2}\ensuremath{\theta}}_{W}\ensuremath{\equiv}1\ensuremath{-}\frac{{M}_{W}^{2}}{{M}_{Z}^{2}}=0.2291\ifmmode\pm\else\textpm\fi{}0.0034$ on-shell scheme, where...
We provide a pedagogical introduction to recently studied class of phenomenologically interesting string models, known as Intersecting D-Brane Models. The gauge fields the Standard-Model are localized on D-branes wrapping certain compact cycles an underlying geometry, whose intersections can give rise chiral fermions. address basic issues and also overview recent activity in this field. This article is intended serve non-experts with explanations fundamental aspects, some orientation for...
The results of a comprehensive analysis existing data on the weak neutral current and W Z masses are presented. principal following. (a) There is no evidence for any deviation from standard model. (b) A global fit to all yields ${\mathrm{sin}}^{2}$${\mathrm{\ensuremath{\theta}}}_{\mathrm{W}}$\ensuremath{\equiv}1-${\mathrm{M}}_{\mathrm{W}}$${\mathrm{}}^{2}$/${\mathrm{M}}_{\mathrm{Z}}$${\mathrm{}}^{2}$=0.230\ifmmode\pm\else\textpm\fi{}0.0048, where this error others given here include full...
This white paper addresses the hypothesis of light sterile neutrinos based on recent anomalies observed in neutrino experiments and latest astrophysical data.
Gauge singlet extensions of the standard model (SM) scalar sector may help remedy its theoretical and phenomenological shortcomings while solving outstanding problems in cosmology. Depending on symmetries potential, such provide a viable candidate for observed relic density cold dark matter or strong first order electroweak phase transition needed baryogenesis. Using simplest extension SM with one real field, we analyze generic implications singlet-extended Higgs boson phenomenology at Large...
This paper is a review of the present status neutrino mass physics, which grew out an APS sponsored study neutrinos in 2004. After discussion knowledge masses and mixing some popular ways to probe new physics implied by recent data, it summarizes what can be learned about interactions as well nature beyond Standard Model from various proposed experiments. The intriguing possibility that may at heart our understanding long standing puzzle cosmology, i.e. origin matter–antimatter asymmetry...
A detailed analysis of existing neutral-current data has been performed in order (a) to determine as fully possible the structure hadronic and leptonic neutral currents without recourse a specific weak-interaction model; (b) search for effects small deviations from Weinberg-Salam (WS-GIM) (c) value ${{sin}^{2}\ensuremath{\theta}}_{w}$ accurately possible. The authors attempt incorporate best theoretical expressions treatment each reactions. For deep-inelastic scattering, example, quantum...
We analyze a simple extension of the standard model (SM) obtained by adding complex singlet to scalar sector (cxSM). show that cxSM can contain one or two viable cold dark matter candidates and conditions on parameters potential yield observed relic density. When contains global $U(1)$ symmetry is both softly spontaneously broken, it candidate ingredients necessary for strong first order electroweak phase transition as needed baryogenesis. also study implications discovery Higgs boson at...
We present a comprehensive review of keV-scale sterile neutrino Dark Matter, collecting views and insights from all disciplines involved - cosmology, astrophysics, nuclear, particle physics in each case viewed both theoretical experimental/observational perspectives. After reviewing the role active neutrinos physics, we focus on context Matter puzzle. Here, first motivation for based challenges tensions purely cold scenarios. then round out discussion by critically summarizing known...
There are theoretical and phenomenological motivations that there may exist additional heavy ${Z}^{\ensuremath{'}}$ bosons with family nonuniversal couplings. Flavor mixing in the quark lepton sectors will then lead to flavor changing couplings of ${Z}^{\ensuremath{'}},$ also ordinary Z when ${Z\ensuremath{-}Z}^{\ensuremath{'}}$ is included. The general formalism such effects described, applications made a variety CP-violating tree loop processes. Results described for three specific cases...
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,...
The status of coupling constant unification in the standard model and its supersymmetric extension are discussed. Uncertainties associated with input constants, $m_{t}$, threshold corrections at low high scales, possible nonrenormalizable operators parametrized estimated. A simple parametrization a general new particle spectrum is given. It shown that an effective scale $M_{SUSY}$ can be defined, but for realistic it may differ considerably from typical masses. implications lower (higher)...
The results of a comprehensive analysis the limits on mixings between ordinary fermions and possible heavy with exotic SU(2)\ifmmode\times\else\texttimes\fi{}U(1) assignments (e.g., left-handed singlets and/or right-handed doublets) are presented. A general formalism for describing such is given. It shown that variety constraints, including relation W Z masses Fermi constant, charged-current universality, induced charged currents, flavor-diagonal neutral currents suffice to limit all...
We consider the phenomenological constraints on mass ${M}_{R}$ and ${W}_{L}\ensuremath{-}{W}_{R}$ mixing angle $\ensuremath{\zeta}$ in a very general class of $\mathrm{SU}{(2)}_{L}\ifmmode\times\else\texttimes\fi{}\mathrm{SU}{(2)}_{R}\ifmmode\times\else\texttimes\fi{}\mathrm{U}(1)$ models. In particular, almost no model-dependent assumptions are made concerning left-right symmetry or Higgs structure theory, which means that ${U}^{R}$, matrix for right-handed quarks, is unrelated to...
It is suggested that the magnetic monopoles predicted by grand unified theories would not be produced in significant numbers if electromagnetic gauge invariance spontaneously broken when temperature $T$ greater than ${T}_{c}\ensuremath{\gtrsim}1$ TeV. A model possessing this behavior displayed and cosmological implications are discussed.
The conclusions of the Physics Working Group international scoping study a future Neutrino Factory and super-beam facility (the ISS) are presented. ISS was carried by community between NuFact05, 7th International Workshop on Factories Superbeams, Laboratori Nazionali di Frascati, Rome, June 21-26, 2005) NuFact06 (Ivine, California, 24{30 August 2006). physics case for an extensive experimental programme to understand properties neutrino is presented role high-precision measurements...
We consider electroweak symmetry breaking in supersymmetric models with an extra nonanomalous ${\mathrm{U}(1)}^{\ensuremath{'}}$ gauge and standard-model singlet scalar $S$. For appropriate charges the forbids elementary $\ensuremath{\mu}$ term, but effective is generated by VEV of $S$, leading to a natural solution problem. There are variety scenarios acceptably small $Z$-${Z}^{\ensuremath{'}}$ mixing other phenomenological consequences, all which involve some not excessive fine-tuning. One...
Within a class of superstring vacua which have an additional nonanomalous U(1)\ensuremath{'} gauge factor, we address the scale symmetry breaking and constraints on exotic particle content their masses. We also show that extra provides new mechanism for generating naturally small effective $\ensuremath{\mu}$ term. In general, existing models are not consistent with all phenomenological constraints; however, they do provide testing ground to above issues, yielding set concrete scenarios....
Mikheyev and Smirnov have recently proposed a novel plausible solution of the solar neutrino problem, based on resonant amplification oscillations in matter. We comment several aspects this mechanism. (i) For values masses mixing angles predicted by seesaw model grand unified theories, MSW effect may take place naturally Sun, leading to considerable reduction flux electron neutrinos, with dominant transition being ve → vτ (rather than vμ). (ii) Oscillations between ordinary neutrinos (ve,...