Precision Measurements of B Meson Decays and Search for Supersymmetry

B介子衰变的精确测量和超对称性的探索

• 批准号: 13304016
• 负责人: AIHARA Hiroaki
• 金额: $ 34.03万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13304016/
• 关键词: Elementary particles; Particle accelerator; CP violation; Symmetry; Solid state detectors; B meson; the Standard Model; Supersymmetry

1)We have searched for physics beyond the Standard Model based on precision measurements of CP violation in B meson system. The B to phi Ks decay is induced by a quantum loop (a.k.a. penguin) process, where New Physics can contribute. CP asymmetry measured in B to phi Ks, therefore, can be different from that in B to J/psi Ks, where only the tree Standard Model process dominates. Based on 152 million B anti-B pairs observed by Belle detector, we have determined CP asymmetry for B to phi Ks to be S=-0.96+-0.52, which is somewhat disagreement with CP asymmetry for B to J/psi Ks, S=+0.733+-0.057+-0.028. We must further improve the statistical accuracy of this measurement to see if this potential discrepancy remains true.2)We have observed large CP violation in B to pi+pi- decay using 152B anti-B pairs, for the first time.3)We have measured, for the first time, the inclusive branching faction of Flavor Changing Neutral Currents process, b to s l+l-, where l can be an electron or a muon. We determined Br(b to sl+l-) to be (4.39+-0.84+0.78-0.73) x 10-6. This measurement can be used to constrain many New Physics models including Supersymmetric model.

1)在精确测量B介子系统CP破坏的基础上，寻找超越标准模型的物理。B到Phi Ks的衰变是由量子环路(又称.企鹅)过程，新物理学可以在这一过程中做出贡献。因此，在B到Phi Ks中测量的CP不对称性可能与在B到J/psi Ks中测量的不对称性不同，在B到J/psi Ks中，只有树标准模型过程占主导地位。根据Belle探测器观测到的1.52亿对B抗B对，我们确定B到PhiKs的CP不对称性为S=-0.96+-0.52，这与B到J/psi Ks的CP不对称性S=+0.733+-0.057+-0.028有些不同。我们必须进一步提高这一测量的统计精度，以确定这种势差异是否仍然成立。2)我们首次使用152B反B对观察到了B到pi+pi-衰变中的大CP破坏。3)我们首次测量了风味变化中性流过程的包含性分支，b到S L+L-，其中L可以是电子或介子。确定了Br(b to sl+L-)=(4.39+-0.84+0.78-0.73)×10-6。这种测量可以用来约束许多新的物理模型，包括超对称模型。

项目成果

Measurement of |V(ub)|Using Inclusive X(u) 1 nu Decays with a Novel X(u)-Reconstruction Method

通过新颖的 X(u) 重建方法使用包含 X(u) 1 nu 衰减来测量 |V(ub)|

• 发表时间: 2004
• 期刊: Physical Review Letters 92
• 作者: Bocherer;Siegfried;Furusawa;Masaaki;H.Kakuno et al.
• 通讯作者: H.Kakuno et al.

K.Abe et al.: "Improved Measurement of Mixing-induced CP Violation in the Neutral B Meson System"Physical Review D. 6. 071102(R) (2002)

K.Abe 等人：“中性 B 介子系统中混合引起的 CP 破坏的改进测量”物理评论 D. 6. 071102(R) (2002)

Observation of Large CP Violation and Evidence for Direct CP Violation in BO to pi+pi- Decays

BO 到 pi pi- 衰变中大 CP 破坏的观察和直接 CP 破坏的证据

• 发表时间: 2004
• 期刊: Physical Review Letters 93
• 作者: K.Abe et al.

K.Abe et al.: "Study of Time-Dependent CP-Violating Asymmetries in b to s qbar q Decays"Physical Review D. 67. 031102(R) (2003)

K.Abe 等人：“b 到 s qbar q 衰变中的时间依赖性 CP 破坏不对称性的研究”物理评论 D. 67. 031102(R) (2003)

Measurement of Time-Dependent CP-Violating Asymmetries in BO to phi KsO, K+K-KsO and eta' KsO Decays

BO 到 phi KsO、K K-KsO 和 eta KsO 衰减中随时间变化的 CP 破坏不对称性的测量

• 发表时间: 2003
• 期刊: Physical Review Letters 91
• 作者: 伊吹山 知義;K.Abe et al.
• 通讯作者: K.Abe et al.