Anti-bottom quark

Anti-bottom quark
Name	Anti-bottom quark
Generation	Third
Charge	+1/3 e
Spin	1/2
Color	Antitriplet
Mass	~4.18 GeV/c^2 (constituent-related)
Antiparticle	Bottom quark

Anti-bottom quark

Introduction

The anti-bottom quark is the antiparticle of the bottom quark and occupies the third generation alongside the top quark, with ties to studies at CERN, Fermilab, SLAC National Accelerator Laboratory, Brookhaven National Laboratory and collaborations such as ATLAS Collaboration, CMS Collaboration, LHCb, CDF Collaboration and DZero. Research into the anti-bottom quark informs investigations by projects like the Large Hadron Collider, Tevatron, Belle II, BaBar, LEP and experiments linked to institutions including University of Cambridge, Harvard University, Stanford University, Massachusetts Institute of Technology, University of Oxford and California Institute of Technology. Insights from the anti-bottom quark contribute to theoretical work by groups around figures like Sheldon Glashow, Steven Weinberg, Abdus Salam, Murray Gell-Mann and Richard Feynman and underpin analyses in frameworks associated with the Standard Model (particle physics), Cabibbo–Kobayashi–Maskawa matrix, CP violation and searches for physics beyond the Standard Model.

Properties

The anti-bottom quark carries electric charge +1/3 e and has spin 1/2, properties cataloged alongside other fermions in resources from Particle Data Group and summarized in review articles by authors affiliated with Institute for Advanced Study, Princeton University, CERN Theory Division, Perimeter Institute and Kavli Institute for Theoretical Physics. Its mass, determined through lattice QCD and perturbative techniques developed by researchers at ETH Zurich, Institute for Nuclear Theory and Yukawa Institute for Theoretical Physics, is often quoted in relation to the bottom quark mass used by collaborations such as PDG and analyses from ZEUS Collaboration and H1 Collaboration. The anti-bottom quark participates in color interactions described by Quantum Chromodynamics, with color antitriplet representations studied by groups at SLAC, DESY and IHEP.

Production and decay

Anti-bottom quarks are produced in high-energy collisions at facilities like Large Hadron Collider, Tevatron, LEP, HERA and KEK and observed in decay chains analyzed by LHCb, ATLAS Collaboration, CMS Collaboration, Belle Collaboration and BaBar Collaboration. Production mechanisms include gluon splitting and flavor excitation modeled with event generators developed by teams at CERN, Fermilab, Brookhaven National Laboratory, Lawrence Berkeley National Laboratory and companies partnering with GEANT4 authors; these models are tuned using data sets from Run 1 (LHC), Run 2 (LHC), Run 3 (LHC), Tevatron Run II and B-factory experiments. Anti-bottom quark hadronization leads to mesons and baryons such as anti-bottom mesons and antibaryons, whose weak decays probe parameters measured by collaborations like BABAR, Belle II, CLEO and LHCb and feed into fits performed by groups at CKMfitter Group and UTFit Collaboration.

Interactions and role in the Standard Model

The anti-bottom quark interacts via the strong, weak and electromagnetic forces as formalized in the Standard Model (particle physics) and encoded in the Cabibbo–Kobayashi–Maskawa matrix, with phenomenology explored in theoretical work by researchers at CERN Theory Division, Perimeter Institute, Institute for Advanced Study, Brookhaven National Laboratory and SLAC. Its weak interactions mediate flavor-changing processes that reveal CP violation and contribute to measurements constraining parameters associated with unitarity triangle analyses undertaken by teams at CKMfitter Group, UTFit Collaboration and experimental collaborations like LHCb, Belle II and BaBar. Strong interaction effects involving the anti-bottom quark are calculated using lattice QCD and effective field theories championed by groups at Riken, RIKEN BNL Research Center, Institute of Physics (China), Max Planck Institute for Physics and Institut de Physique Théorique.

Experimental detection and observations

Signatures of the anti-bottom quark are extracted from displaced vertices, secondary tracks and jet substructure in detectors built by consortia including ATLAS Collaboration, CMS Collaboration, LHCb, CDF Collaboration and DZero, with reconstruction algorithms developed by teams at University of Chicago, University of California, Berkeley, Imperial College London, University of Tokyo and University of Melbourne. Measurements of anti-bottom containing hadrons, branching fractions and mixing phenomena have been reported by LHCb, Belle, BaBar, CDF and ALEPH and incorporated into global fits by Particle Data Group, CKMfitter Group and UTFit Collaboration. Experimental programs at CERN, KEK, Fermilab and J-PARC continue to refine uncertainties affecting tests led by consortia including LHCb Upgrade, Belle II Collaboration and multinational working groups affiliated with ICFA.

Theoretical implications and extensions

Studies of the anti-bottom quark constrain extensions to the Standard Model (particle physics) such as Supersymmetry, Extra dimensions, Technicolor, Two-Higgs-doublet model and models invoking flavor-changing neutral currents, with phenomenology worked out by theorists at CERN Theory Division, Perimeter Institute, Institute for Advanced Study, Harvard University and University of Cambridge. Precision measurements involving anti-bottom processes inform searches for heavy mediators postulated in frameworks associated with Grand Unified Theory, Left–right symmetric model, Minimal Flavor Violation and hypotheses explored at conferences like International Conference on High Energy Physics, Flavor Physics and CP Violation Conference and workshops hosted by CERN and KEK. Ongoing theoretical efforts connect anti-bottom observables to cosmological questions studied by researchers at Princeton University, Stanford University, Caltech and Institute for Advanced Study concerning baryogenesis scenarios and the matter–antimatter asymmetry.

Category:Quarks Category:Antiparticles Category:Elementary particles