Search for a Fourth-Generation Quark More Massive than the Z{sup 0} Boson in pp Collisions at {radical}(s) =1.8 TeV
- Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
- Waseda University, Tokyo 169, (Japan)
- Rockefeller University, New York, New York 10021 (United States)
- Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States)
- Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637 (United States)
- Istituto Nazionale di Fisica Nucleare, University and Scuola Normale Superiore of Pisa, I-56100 Pisa, (Italy)
- University of Michigan, Ann Arbor, Michigan 48109 (United States)
- Institute of Physics, Academia Sinica, Taipei, Taiwan 11529, Republic of China (China)
We present the results of a search for pair production of a fourth-generation charge -(1/3) quark (b{sup '}) in {radical}(s)=1.8 TeV pp collisions using 88 pb{sup -1} of data obtained with the Collider Detector at Fermilab. We assume that both quarks decay via the flavor-changing neutral current process b{sup '}{yields}bZ{sup 0} and that the b{sup '} mass is greater than m{sub Z}+m{sub b} . We studied the decay mode b{sup '}b{sup '}{yields}Z{sup 0}Z{sup 0}bb where one Z{sup 0} decays into e{sup +}e{sup -} or {mu}{sup +}{mu}{sup -} and the other decays hadronically, giving a signature of two leptons plus jets. An upper limit on the {sigma}{sub pp{yields}}{sub b{sup '}}{sub b{sup '}}x[B(b{sup '} {yields}bZ{sup 0})]{sup 2} is established as a function of the b{sup '} mass. We exclude at 95% confidence level a b{sup '} quark with mass between 100 and 199 GeV/c{sup 2} for B(b{sup '}{yields}bZ{sup 0})=100% . (c) 2000 The American Physical Society.
- OSTI ID:
- 20215354
- Journal Information:
- Physical Review Letters, Vol. 84, Issue 5; Other Information: PBD: 31 Jan 2000; ISSN 0031-9007
- Country of Publication:
- United States
- Language:
- English
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