• Search Research Projects
  • Search Researchers
  • How to Use
  1. Back to previous page

Decay Properties of the Neutral B Meson with Strangeness

Research Project

Project/Area Number 13440065
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field 素粒子・核・宇宙線
Research InstitutionUniversity of Tsukuba

Principal Investigator

UKEGAWA Fumihiko  University of Tsukuba, Institute of Physics, Associate Professor, 物理学系, 助教授 (10312795)

Co-Investigator(Kenkyū-buntansha) HARA Kazuhiko  University of Tsukuba, Institute of Physics, Assistant Professor, 物理学系, 講師 (20218613)
KIM Shinhong  University of Tsukuba, Institute of Physics, Professor, 物理学系, 教授 (50161609)
TAKIKAWA Koji  University of Tsukuba, Institute of Physics, Professor, 物理学系, 教授 (00011635)
SEIYA Yoshihiro  University of Tsukuba, Institute of Physics, Assistant Professor, 物理学系, 講師 (80251031)
Project Period (FY) 2001 – 2002
Project Status Completed (Fiscal Year 2002)
Budget Amount *help
¥8,000,000 (Direct Cost: ¥8,000,000)
Fiscal Year 2002: ¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 2001: ¥5,400,000 (Direct Cost: ¥5,400,000)
Keywordspp^^- Collisions / B Mesons / Weak Interactions / Lifetimes / Particle Oscillations / CKM Matrix / Unitarity Triangle / Proper Decay Time / ユニタリ三角系
Research Abstract

The research has been conducted by studying proton-antiproton collisions and B-hadron signals observed and reconstructed with the CDF detector at the Tevatron collider at Fermi National Accelerator Laboratory in USA. The CDF Run-II experiment started in 2001. Since then the accelerator performance has improved steadily, achieving a best instantaneous luminosity of L = 4.7 x 10^<31> cm^<-2> s^<-1>. And CDF has thus far accumulated 170 pb^<-1> of data, surpassing that of Run I (1992 - 1996), 110 pb^<-1>. The CDF detector, after a major upgrade, has been operational smoothly after the initial commissioning and calibration phases.
The B-physics capability of CDF has been enhanced as well. In the studies of B hadron decays, precision track reconstruction using silicon micro-strip detectors, and particle identification, are important. In CDF Run II, a device called Silicon Vertex Trigger (SVT) has been introduced, which uses information of the silicon detectors at the second level of the trig … More ger. It has enabled us to collect efficiently the decay products of long-lived particles such as B and charm hadrons. With this, we are now able to trigger on decay modes consisting of only hadrons, such as B^^-^0_s → D^+_sπ^- and B^0/B^^-^0 → π^+π^-. As for particle identification, a time-of-flight (TOF) system has been added. It has achieved a time resolution of 110 ps, close to the design value of 100 ps. It provies a kaon-pion separation at low momentum regions. The main purpose of the TOF system is to use charged kaons for the identification of initial flavor of the B mesons. Also, the TOF system should be useful in achieving a high signal-to-noise ratio in the B^0_s reconstruction, because there is a high probability that a K^+K^- pair is produced in the B^0_s meson decays. At higher momentum regions the dE/dx information from the main tracking chamber provides a 1.2-σ K-π separation.
Analyses of collision data are in progress, and we expect in the near future several results, including the measurements of the B^0_s meson lifetime and the branching fraction of the B^^-^0_s → D^+_sπ^- relative to B^^-^0 → D^+π^-, and the search for the lifetime difference between the two mass eigenstates of the B^0_sB^^-^0_s system. And then we will look for the B^0_sB^^-^0_s oscillations after optimizing flavor tagging algorithms. In a longer term, we will perform measurements of CP-violating asymmetries in the decays B^0_s/B^^-^0_s → J/ψφ and B^0_s/B^^-^0_s → K^+K^-. Less

Report

(3 results)
  • 2002 Annual Research Report   Final Research Report Summary
  • 2001 Annual Research Report
  • Research Products

    (23 results)

All Other

All Publications (23 results)

  • [Publications] T.Affolder, F.Ukegawa et al.: "Observation of orbitally excited B mesons in pp^^-collisions at √<s>=1.8TeV"Physical Review D. 64. 072002-1-072002-16 (2001)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] T.Affolder, F.Ukegawa et al.: "Production of X_<c1> and X_<c2> in p^^-collisions at √<s>=1.8TeV"Physical Review Letters. 86. 3963-3968 (2001)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] D.Acosta, F.Ukegawa et al.: "Measurement of the B^+ total cross section and B^+ differential cross section dσ/dp_T in pp^^-collisions at √<s>=1.8TeV"Physical Review D. 65. 052005-1-052005-10 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] D.Acosta, F.Ukegawa et al.: "Search for the decay B_s→μ^+μ^-φ in pp^^-collisions at √<s>=1.8TeV"Physical Review D. 65. 111101-1-111101-6 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] T.Affolder, F.Ukegawa et al.: "Study of B^O→J/ψK^<(*)O>π^+π^-decays with the Collider Detector at Fermilab"Physical Review Letters. 88. 071801-1-071801-6 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] D.Acosta, F.Ukegawa et al.: "Branching ratio measurements of exclusive B^+ decays to charmonium with the Collider Detector at Fermilab"Physical Review D. 66. 052005-1-052005-7 (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] T.Affolder, F.Ukegawa et al.: "Observation of orbitally excited B mesons in pp^^- collisions at √<s> = 1.8 TeV"Physical Review D. 64. 072002 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] T.Affolder, F.Ukegawa et al.: "Production of χ_<c1> and χ_<c2> in pp^^- collisions at √<s> = 1.8 TeV"Physical Review Letters. 86. 3963 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] D.Acosta, F.Ukegawa et al.: "Measurement of the B^+ total cross section and B^+ differential cross section dσ/dp_T in pp^^- collisions at √<s> = 1.8 TeV"Physical Review D. 65. 052005 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] D.Acosta, F Ukegawa et al.: "Search for the decay B_s → μ^+μ^-φ in pp^^- collisions at √<s> = 1.8 TeV"Physical Review D. 65. 111101 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] T.Affolder, F.Ukegawa et al.: "Study of B^0 → J/ψK^<(*)0>π^+π^- decays with the Collider Detector at Fermilab"Physical Review Letters. 88. 071801 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] D.Acosta, F.Ukegawa et al.: "Branching ratio measurements of exclusive B^+ decays to charmonium with the Collider Detector at Fermilab"Physical Review D. 66. 052005 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2002 Final Research Report Summary
  • [Publications] T.Affolder, F.Ukegawa et al.: "Observation of orbitally excited B mesons in pp^^-collisions at √<s>=1.8 TeV"Physical Review D. 64. 072002 (2001)

    • Related Report
      2002 Annual Research Report
  • [Publications] T.Affolder, F.Ukegawa et al.: "Production of X_<ci> and X_<c2> in pp^^-collisions at √<s>=1.8 TeV"Physical Review Letters. 86. 3963-3968 (2001)

    • Related Report
      2002 Annual Research Report
  • [Publications] D.Acosta, F.Ukegawa et al.: "Measurement of the B^+ total cross section and B^+ differential cross section dσ/dp_T in pp^^-collisions at √<s>=1.8 TeV"Physical Review D. 65. 052005 (2002)

    • Related Report
      2002 Annual Research Report
  • [Publications] D.Acosta, F.Ukegawa et al.: "Search for the decay B_s→μ^+μ^-φ in pp^^-collisions at √<s>=1.8 TeV"Physical Review D. 65. 111101 (2002)

    • Related Report
      2002 Annual Research Report
  • [Publications] T.Affolder, F.Ukegawa et al.: "Study of B^0 →J/ψK^<(*)0>π^+π^-decays with the Collider Detector at Fermilab"Physical Review Letters. 88. 071801 (2002)

    • Related Report
      2002 Annual Research Report
  • [Publications] D.Acosta, F.Ukegawa et al.: "Branching ratio measurements of exclusive B^+ decays to charmonium with the Collider Detector at Fermilab"Physical Review D. 66. 052005 (2002)

    • Related Report
      2002 Annual Research Report
  • [Publications] T.Affolder, F. Ukegawa, K. Hara, S. Kim, Y. Seiya, K. Takikawa et al.: "Production of χ_<c1> and χ_<c2> in p pbar Collisions at √s = 1.8 TeV"Physical Review Letters. 86. 3963-3968 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] T.Affolder, F. Ukegawa, K. Hara, S. Kim, Y. Seiya, K. Takikawa et al.: "Observation of Orbitally Excited B Mesons in p pbar Collisions at √s = 1.8 TeV"Physical Review D. 64. 072002-1_16 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] T.Affolder, F. Ukegawa, K. Hara, S. Kim, Y. Seiya, K. Takikawa et al.: "Study of B^0 →J/ψ K^<(*)0> π^+ π^- Decays with the Collider Detector at Fermilab"Physical Review Letters. 88. 071801-1_6 (2002)

    • Related Report
      2001 Annual Research Report
  • [Publications] Ch. Paus, F. Ukegawa, S. Kim, K. Takikawa et al.: "Design and Performance Tests of the CDF Time-of-Flight System"Nulcear Instruments and Methods in Physical Research Section A. 461. 579-581 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] C. Grozis, F. Ukegawa, S. Kim, K. Takikawa et al.: "The Time-of-Flight Detector at CDF"Nuclear Physics B,Proceedings Supplements. 93. 344-347 (2001)

    • Related Report
      2001 Annual Research Report

URL: 

Published: 2001-04-01   Modified: 2016-04-21  

Information User Guide FAQ News Terms of Use Attribution of KAKENHI

Powered by NII kakenhi