Inclusive Lambda_c Production in e+e- Annihilations at sqrt{s}=10.54 GeV and in Upsilon(4S) Decays
We present measurements of the total production rates and momentum distributions of the charmed baryon {Lambda}{sub c}{sup +} in e{sup +}e{sup -} {yields} hadrons at a center-of-mass energy of 10.54 GeV and in {Upsilon}(4S) decays. In hadronic events at 10.54 GeV, charmed hadrons are almost exclusively leading particles in e{sup +}e{sup -} {yields} c{bar c} events, allowing direct studies of c-quark fragmentation. We measure a momentum distribution for {Lambda}{sub c}{sup +} baryons that differs significantly from those measured previously for charmed mesons. Comparing with a number of models, we find none that can describe the distribution completely. We measure an average scaled momentum of (x{sub p}) = 0.574 {+-} 0.009 and a total rate of N{sub {Lambda}{sub c}}{sup q{bar q}} = 0.057 {+-} 0.002(exp.) {+-} 0.015(BF) {Lambda}{sub c}{sup +} per hadronic event, where the experimental error is much smaller than that due to the branching fraction into the reconstructed decay mode, pK{sup -} {pi}{sup +}. In {Upsilon}(4S) decays we measure a total rate of N{sub {Lambda}{sub c}}{sup {Upsilon}} = 0.091 {+-} 0.006(exp.) {+-} 0.024(BF) per {Upsilon}(4S) decay, and find a much softer momentum distribution than expected from B decays into a {Lambda}{sub c}{sup +} plus an antinucleon and one to three pions.
- Research Organization:
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC02-76SF00515
- OSTI ID:
- 891233
- Report Number(s):
- SLAC-PUB-12074; hep-ex/0609004; TRN: US200622%%68
- Journal Information:
- Submitted to Physical Review D, Journal Name: Submitted to Physical Review D
- Country of Publication:
- United States
- Language:
- English
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