B^0_s

B^0_s
Name	B^0_s
Composition	bottom antiquark and strange quark
Type	neutral meson
Mass	5366.88 MeV/c^2 (approx.)
Lifetime	1.510 ps (approx.)

B^0_s. The B^0_s meson is a neutral hadron composed of a bottom antiquark and a strange quark. It occupies a central role in flavor physics probed by experiments such as CERN, Fermilab, KEK, BaBar, Belle, LHCb, ATLAS, and CMS. Studies of B^0_s inform tests of the Cabibbo–Kobayashi–Maskawa matrix, constraints on the Standard Model (particle physics), and searches for CP violation beyond established sources.

Introduction

The B^0_s meson was first observed in high-energy collisions at facilities including Tevatron experiments like CDF and DØ and later measured with precision at Large Hadron Collider experiments such as LHCb, ATLAS, and CMS. Its properties are interpreted within frameworks developed by theorists at institutions like SLAC National Accelerator Laboratory, Brookhaven National Laboratory, and universities including Oxford University, Cambridge University, MIT, Caltech, and Princeton University. Precise B^0_s results influence global fits carried out by collaborations such as UTfit, CKMfitter, and analyses connected to the Particle Data Group.

Properties

The B^0_s is a pseudoscalar meson with quantum numbers J^P = 0^- and a mass measured by experiments such as LHCb Collaboration and reported by the Particle Data Group. Its lifetime and decay constants are computed with methods including lattice QCD by groups at CERN Theory and FNAL collaborations, and compared to perturbative calculations by theorists like those at Institute for Advanced Study and Perimeter Institute. Mixing parameters Δm_s and ΔΓ_s connect to calculations from Heavy Quark Effective Theory and influence fits in global analyses undertaken by Belle II and BaBar researchers.

Production and Detection

B^0_s mesons are produced in hadron collisions at colliders such as LHC, Tevatron, and in e+e− environments at asymmetric factories like KEKB. Detectors including LHCb, ATLAS, CMS, CDF, DØ, Belle, and BaBar use subsystems developed at laboratories like CERN, SLAC, and KEK: tracking systems inspired by LEP experiments, vertex detectors analogous to those at ALEPH, DELPHI, OPAL, and L3, particle identification systems akin to RICH detectors, and calorimetry and muon systems designed by collaborations including ALICE and NA62. Trigger and data acquisition frameworks built by groups at Fermilab and CERN select B^0_s candidates for analyses by teams from University of Oxford, University of Cambridge, University of Zurich, University of Tokyo, and University of Barcelona.

Mixing and CP Violation

Neutral B^0_s–anti-B^0_s oscillations are characterized by parameters Δm_s and ΔΓ_s measured by collaborations such as LHCb Collaboration, CDF, and DØ. CP-violating phase φ_s is probed in decays like B^0_s → J/ψ φ by experiments at LHCb, ATLAS, and CMS, and interpreted in theoretical works by researchers at CERN Theory and IPPP Durham. Constraints on new physics scenarios arise from comparisons with predictions from models developed at institutions like DESY, SLAC, Perimeter Institute, Institute for High Energy Physics (IHEP), and groups studying supersymmetry and flavor-changing neutral currents at Institute for Theoretical and Experimental Physics.

Decay Modes

Prominent decay channels include B^0_s → J/ψ φ, B^0_s → μ+ μ−, B^0_s → D_s^(±) π^(∓), and B^0_s → K+ K− examined by LHCb, CMS, ATLAS, CDF, and Belle teams. Rare decays like B^0_s → μ+ μ− provide constraints compared with predictions from computations by groups at KITP, Brookhaven National Laboratory, FNAL Lattice Collaboration, and theorists associated with IHEP Beijing. Analyses of hadronic final states draw on models from QCD practitioners at CERN, DESY, University of Chicago, and Laboratoire de Physique Théorique (LPT).

Experimental Measurements

Key measurements include Δm_s determined by CDF and refined by LHCb, branching fractions for B^0_s → μ+ μ− measured by CMS and LHCb, and CP-violating phase φ_s reported by LHCb, ATLAS, and CMS. Precision results are compiled by the Particle Data Group and inform global fits by CKMfitter and UTfit. Detector performance and analysis techniques are advanced in publications from collaborations like LHCb Collaboration, ATLAS Collaboration, and CMS Collaboration, and discussed at conferences such as Moriond, ICHEP, EPS-HEP, and workshops at CERN and IPPP Durham.

Theoretical Significance

B^0_s physics constrains elements of the Cabibbo–Kobayashi–Maskawa matrix and tests the Standard Model (particle physics) through analyses performed by theorists at IPMU, Theory Group at CERN, Perimeter Institute, and Institute for Advanced Study. Deviations in mixing, CP violation, or rare decay rates could indicate physics from frameworks developed at DESY, SLAC, Brookhaven National Laboratory, FNAL, or beyond—such as supersymmetry, extra dimensions, or Z' models explored at IHEP. Results feed into broader particle physics programs involving collaborations at LHCb, Belle II, ATLAS, CMS, and proposals discussed at meetings like Snowmass and European Strategy for Particle Physics.

Category:Mesons Category:Bottom mesons