Bottom Quark Studies

这项建议要求对罗切斯特大学高能物理组的研究计划给予支持。 该小组集中研究电子-正电子碰撞束物理学，在位于康奈尔大学的CESR电子-正电子储存环的CLEO合作范围内工作，并得到NSF的支持。这个小组过去的研究集中在B夸克衰变上。在过去的三年CGI奖，成员的罗切斯特集团已发挥领导作用，在CLEO，作为分析协调员和共同发言人。 作为NSF赞助的CESR加速器和CLEO探测器升级到CLEO III的一部分，他们帮助设计和建造了一个新的漂移室，用于寻找和测量带电粒子。 在对CLEO II数据的物理分析中，他们研究了B夸克衰变为粲夸克和反粲夸克的过程，这项研究有助于解释为什么测量到的B夸克衰变为电子或μ子的速率比理论上预期的要小。在这个提案的三年期间，该小组计划两个主要的物理分析项目。 第一个是对无粲半轻子B衰变的研究，B u 1 n，这将导致CKM矩阵元素V（u B）的测量达到10%的精度。 实际测量将是衰变B p l n和B r l n的测量，它们覆盖了B u l n相空间的很大一部分。 第二个项目是寻找和研究罕见的B衰变过程B s g，B s l+ l-和B s n n-bar，下降到夸克和轻子标准模型预测的水平，以便找到超越标准模型的物理学证据，例如，超对称性，或者对这种模型施加严格的限制。

This proposal requests support for the research program of the high energy physics group at the University of Rochester. This group has concentrated on electron-positron colliding beam physics, working within the CLEO collaboration at the CESR electron-positron storage ring located at Cornell University and supported by the NSF. Past studies by this group have focussed on b quark decay. During the previous three-year CGI award, members of the Rochester group have played leadership roles in CLEO, as Analysis Coordinator and as CoSpokesman. As part of the NSF-sponsored upgrade of the CESR accelerator and CLEO detector to CLEO III, they have helped in the design and construction of a new drift chamber for finding and measuring charged particles. In physics analysis of CLEO II data, they have studied the decay of the b quark to charm and anticharm quarks, a study which helps explain why the measured b quark decay rate to electrons or muons is smaller than expected theoretically. During the three-year period of this proposal, the group plans two major physics analysis projects. The first is a study of charmless semileptonic b decay, i.e., b u l n, which should lead to a measurement of the CKM matrix element V(ub) to an accuracy of 10%. The actual measurments will be of the decays B p l n and B r l n which cover a large fraction of the b u l n phase space. The second project is a search for and study of the rare b decay processes b s g, b s l+ l-, and b s n n-bar down to levels predicted by the Standard Model of quarks and leptons in order either to find evidence for physics beyond the Standard Model, e.g., supersymmetry, or to place severe constraints on such models.