Preliminary measurement of prompt D{sup {+-}} and D*{sup {+-}} meson production and D*{sup {+-}} spin alignment in hadronic Z{sup 0} decays
- Nagoya Univ. (Japan)
- Tohoku Univ., Sendai (Japan)
- Stanford Univ., CA (United States). Stanford Linear Accelerator Center; and others
The authors have measured the production rates as a function of scaled energy x of prompt charmed pseudoscalar D{sup {+-}} and vector D*{sup {+-}} mesons in hadronic Z{sup 0} decays. The prompt signal components were isolated from the background of D mesons from B hadron decays using impact parameters of reconstructed D{sup {+-}} {yields} K{sup {minus_plus}}{pi}{sup {+-}}{pi}{sup {+-}} and D*-daughter D{sup 0} {yields} K{sup {minus}}{pi}{sup +} and D{sup 0} {yields} K{sup {minus}}{pi}{sup +}{pi}{sup {minus}}{pi}{sup +} candidates. Using the combined meson production rates the authors have measured the fraction of hadronic Z{sup 0} decays into c{bar c}, R{sub c} = 0.182 {+-} 0.027 (stat.) {+-} 0.012 (syst.) (Preliminary). Comparison of the D*{sup {+-}} and D{sup {+-}} rates gives a direct probe of vector (V) vs. pseudoscalar (P) meson production for charmed quarks, and for x > 0.4 they have measured P{sub V} = V/(V + P) = 0.65 {+-} 0.09(stat.) {+-} 0.03(syst.) {+-} 0.03 (BR) (Preliminary). They have measured the degree of spin alignment of the D*{sup {+-}} mesons along their flight direction and find it to be consistent with zero. They compared the latter two results with QCD- and model-based predictions of charm-quark jet fragmentation.
- Research Organization:
- SLAC National Accelerator Lab., Menlo Park, CA (United States); Boston Univ., MA (United States); California Univ., Santa Barbara, CA (United States); California Univ., Santa Cruz, CA (United States); Colorado State Univ., Fort Collins, CO (United States); Colorado Univ., Boulder, CO (United States); Univ. of Illinois at Urbana-Champaign, IL (United States); Univ. of California, Berkeley, CA (United States); Massachusetts Univ., Amherst, MA (United States); Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Oregon Univ., Eugene, OR (United States); Univ. of Wisconsin, Madison, WI (United States); Yale Univ., New Haven, CT (United States); Tennessee Univ., Knoxville, TN (United States)
- Sponsoring Organization:
- USDOE Office of Energy Research, Washington, DC (United States); National Science Foundation, Washington, DC (United States); United Kingdom Particle Physics and Astronomy Research Council (United Kingdom); Istituto Nazionale di Fisica Nucleare, Rome (Italy); Japan-US Cooperative Research Project on High Energy Physics, Nagoya (Japan); Korea Science and Engineering Foundation (Korea, Republic of)
- DOE Contract Number:
- AC03-76SF00515; FG02-91ER40676; FG03-91ER40618; FG03-92ER40689; FG03-93ER40788; FG02-91ER40672; FG02-91ER40677; AC03-76SF00098; FG02-92ER40715; FC02-94ER40818; FG03-96ER40969; FG02-95ER40896; FG02-92ER40704; FG02-91ER40627
- OSTI ID:
- 521613
- Report Number(s):
- SLAC-PUB-7574; CONF-970787-2; CONF-970870-2; ON: DE97007962; CNN: Grant NSF PHY-91-13428; PHY-89-21320; PHY-92-04239; PHY-95-10439; PHY-88-19316; PHY-92-03212; TRN: 97:018422
- Resource Relation:
- Conference: 18. international symposium on lepton photon interactions, Hamburg (Germany); Jerusalem (Israel), 28 Jul - 1 Aug 1997; 19-26 Aug 1997; Other Information: PBD: Jun 1997
- Country of Publication:
- United States
- Language:
- English
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