在质心能量为1.8 TeV的质子-质子对撞中寻找一种质量比Z0玻色子更大的第四代夸克。

Search for a fourth-generation quark more massive than the Z0 boson in p&pmacr; collisions at radicals = 1.8 TeV.

作者信息

Trischuk W, Truitt S, Tseng J, Turini N, Ukegawa F, Valls J, Vejcik S, Velev G, Vidal R, Vilar R, Vologouev I, Vucinic D, Wagner RG, Wagner RL, Wahl J, Wallace NB, Walsh AM, Wang C, Wang CH, Wang MJ, Watanabe T, Waters D, Watts T, Webb R, Wenzel H

机构信息

Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.

出版信息

Phys Rev Lett. 2000 Jan 31;84(5):835-40. doi: 10.1103/PhysRevLett.84.835.

DOI:10.1103/PhysRevLett.84.835

PMID:11017385

Abstract

We present the results of a search for pair production of a fourth-generation charge -1 / 3 quark (b(')) in sqrt[s] = 1.8 TeV p&pmacr; collisions using 88 pb(-1) of data obtained with the Collider Detector at Fermilab. We assume that both quarks decay via the flavor-changing neutral current process b(')-->bZ(0) and that the b(') mass is greater than m(Z)+m(b). We studied the decay mode b(')b(');-->Z(0)Z(0)b&bmacr; where one Z0 decays into e(+)e(-) or &mgr;(+)&mgr;(-) and the other decays hadronically, giving a signature of two leptons plus jets. An upper limit on the sigma(p&pmacr;-->b(')b(');)xB(b(')-->bZ(0)) is established as a function of the b(') mass. We exclude at 95% confidence level a b(') quark with mass between 100 and 199 GeV/c(2) for B(b(')-->bZ(0)) = 100%.

摘要

我们展示了在费米实验室对撞机探测器获取的88pb⁻¹数据的√s = 1.8 TeV pˉp碰撞中寻找第四代电荷为 -1/3夸克（b(')）对产生的结果。我们假设两个夸克都通过味改变中性流过程b(')-->bZ⁰衰变，并且b(')质量大于m(Z)+m(b)。我们研究了衰变模式b(')b(');-->Z⁰Z⁰bˉb，其中一个Z⁰衰变成e⁺e⁻或μ⁺μ⁻，另一个强子衰变，给出两个轻子加喷注的信号。建立了σ(pˉp-->b(')b(');)x[B(b(')-->bZ⁰)]²作为b(')质量函数的上限。对于B(b(')-->bZ⁰) = 100%，我们在95%置信水平下排除了质量在100至199 GeV/c²之间的b(')夸克。