B_s meson

B_s meson
Name	B_s meson
Other names	B_s^0
Composition	strange quark + bottom antiquark
Antiparticle	anti-B_s meson
Mass	≈ 5.366 GeV/c^2
Lifetime	≈ 1.5 ps

B_s meson The B_s meson is a neutral bound state composed of a bottom-type constituent and a strange-type constituent first observed in high-energy experiments. It occupies a central role in tests of the Standard Model through studies of flavor physics, mixing, and CP violation, and has been produced and analyzed by major collaborations at accelerator facilities worldwide.

Overview

The particle was identified in experiments at accelerator complexes including CERN, Fermilab, KEK, SLAC National Accelerator Laboratory, and later studied at detectors such as LHCb, ATLAS, CMS, CDF, and DØ. Its discovery and subsequent precision measurements involved collaborations like ALEPH, OPAL, Belle, BaBar, CLEO, ZEUS, H1, and theoretical interpretation from groups at institutions such as Princeton University, Harvard University, University of Cambridge, Massachusetts Institute of Technology, University of Tokyo, Max Planck Society, and CERN Theory Division.

Composition and properties

The meson is a bound state of a strange quark and a bottom antiquark produced in quantum chromodynamics calculations and lattice simulations by teams at Brookhaven National Laboratory, Argonne National Laboratory, Lawrence Berkeley National Laboratory, Rutherford Appleton Laboratory, and universities including Oxford University, University of California, Berkeley, University of Chicago, Columbia University, and University of Michigan. Its quantum numbers and mass spectrum have been computed with methods developed by researchers affiliated with Institute for Advanced Study, Perimeter Institute, École Normale Supérieure, University of Bonn, University of Padua, University of Barcelona, University of Edinburgh, and University of Melbourne.

Production and detection

Production channels originate from proton–proton and proton–antiproton collisions at facilities such as Large Hadron Collider, Tevatron, SuperKEKB, and fixed-target experiments at CERN SPS. Detection strategies used by collaborations including LHCb, ATLAS, CMS, CDF, and DØ rely on tracking systems and particle identification technologies developed at institutes like DESY, KEK, TRIUMF, Paul Scherrer Institute, Los Alamos National Laboratory, Stanford Linear Accelerator Center, and Fermi National Accelerator Laboratory. Trigger systems and data acquisition systems were engineered by groups from Brookhaven National Laboratory, Imperial College London, University of Wisconsin–Madison, Yale University, University of Maryland, College Park, and Seoul National University.

Decay modes and lifetimes

Key decay channels measured by experimental collaborations include transitions to charmonium and kaon final states studied by LHCb, Belle II, BaBar, CDF, and ATLAS, with branching fractions analyzed by theorists at University of Geneva, SISSA, Universität Hamburg, University of São Paulo, University of Pisa, University of Bonn, and Stockholm University. Lifetime measurements were refined using vertexing systems developed at CERN, KEK, SLAC, Fermilab, and DESY, and compared with predictions from calculations by groups at IHEP (China), INR (Russia), Budker Institute of Nuclear Physics, Tata Institute of Fundamental Research, and Korea Institute for Advanced Study.

CP violation and mixing

Studies of neutral-meson mixing, oscillation frequency, and CP-violating phases have been central to analyses by collaborations such as LHCb, ATLAS, CMS, CDF, and DØ and interpreted in the context of frameworks developed at CERN Theory Division, Perimeter Institute, Institute for Theoretical Physics, Utrecht University, University of Bonn, University of Rome La Sapienza, University of Paris-Sud, IKP Forschungszentrum Jülich, and National Taiwan University. The measurement of the mixing frequency Δm_s and CP-violating phase φ_s involved joint efforts with groups at Los Alamos National Laboratory, SLAC National Accelerator Laboratory, IHEP (Beijing), University of California, San Diego, and University of Manchester.

Experimental results and measurements

Precision results have been published by teams including LHCb, ATLAS, CMS, CDF, DØ, Belle, and BaBar and summarized in reviews from organizations like Particle Data Group, European Physical Society, American Physical Society, International Union of Pure and Applied Physics, and Joint Physics Analysis Center. Global fits and constraints on flavor parameters were produced by consortia involving CKMfitter Group, UTfit, Gfitter Group, FLAG Working Group, and theory groups at CERN, DESY, Brookhaven National Laboratory, RIKEN, and Max Planck Institute for Physics.

Theoretical significance and applications

The meson provides constraints on extensions of the Standard Model studied in models proposed by researchers at Princeton University, Harvard University, Stanford University, MIT, Caltech, Yale University, Johns Hopkins University, University of Chicago, University of California, Los Angeles, University of Rochester, Columbia University, and international collaborations at CERN. Analyses of loop-level processes, box diagrams, and effective Hamiltonians were developed in theoretical work at Institute for Advanced Study, Perimeter Institute, Scuola Normale Superiore, SISSA, University of Padova, University of Milan, University of Pisa, and University of Naples Federico II. Phenomenological implications have influenced searches for new physics at experiments including Large Hadron Collider, International Linear Collider (proposed), SuperKEKB, Fermilab, and proposals discussed at conferences such as HEPTOOLS Workshop, ICHEP, EPS‑HEP, Beauty 2013, and Moriond Conference.

Category:Mesons