Search for a fourth generation charge {minus}1/3 quark via flavor changing neutral currents
There is some likelihood that a light (< m{sub t}) fourth generation charge -1/3 quark (b{prime}) would decay predominantly via loop induced flavor changing neutral currents. The charged current decay of b{prime} to charm would be highly Cabibbo suppressed due to the fact that it changes the generation number by two. The D0 experiment has searched for b{prime} pair production where one or both b{prime} quarks decays via b{prime} {r_arrow} b+{gamma}, giving signatures photon + three jets and two photons + two jets. WE don not see a significant excess of such events over background. In both modes, we set an upper limit on the cross section times branching ratio that is sufficient to rule out a standard sequential b{prime} decaying predominantly via FCNC in the mass range m{sub Z}/2 < m{sub b{prime}} < m{sub Z} + m{sub b}. For b{prime} masses larger than this, the dominant FCNC decay mode is expected to be b{prime} {r_arrow} b + Z. 14 refs., 13 figs., 5 tabs.
- Research Organization:
- Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States); National Science Foundation, Washington, DC (United States); CEA, 75 - Paris (France); Ministry of Science, Higher Education and Technology Policy, Moscow (Russian Federation); Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), Sao Paulo, SP (Brazil); Department of Atomic Energy, Bombay (India). Atomic Minerals Div.; Calciencias; Consejo Nacional de Ciencia y Tecnologia (CONACYT), Mexico City (Mexico); Korea Science and Engineering Foundation (Korea, Republic of); CONICET (Argentina); UBACYT (Argentina); Sloan (Alfred P.) Foundation, New York, NY (United States)
- DOE Contract Number:
- AC02-76CH03000
- OSTI ID:
- 376359
- Report Number(s):
- FNAL/C-96/163-E; CONF-960765-6; ON: DE96013903; TRN: 96:025551
- Resource Relation:
- Conference: 28. international conference on high-energy physics, Warsaw (Poland), 25-31 Jul 1996; Other Information: PBD: Jul 1996
- Country of Publication:
- United States
- Language:
- English
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Search for a Fourth Generation Charge -1/3 Quark via Flavor Changing Neutral Current Decay
Search for a fourth generation charge -1/3 quark via flavor changing neutral current decay