Lifetimes, cross sections, and production mechanisms of charmed particles produced by 20-GeV photons

Journal Article · Wed Jan 01 04:00:00 EST 1986 · Phys. Rev. D; (United States)

DOI:https://doi.org/10.1103/PhysRevD.33.1· OSTI ID:6174368

Abe, K; Armenteros, R; Bacon, T C; Ballam, J; Bingham, H H; Brau, J E; Braune, K; Brick, D; Bugg, W M; Butler, J M

Seventy-one events containing charmed-particle decays have been observed in an experiment using the SLAC Hybrid Facility exposed to a backward-scattered photon beam. Several improvements were made to the apparatus since the previous experiment on charm photoproduction. Results for the charmed-meson lifetimes are consistent with the published results from the previous experiment and the two data samples have been combined yielding a total sample of 136 charm events. After imposing rigorous cuts, 50 neutral, 48 charged, and 2 charged/neutral ambiguous decays remain. From these, the charmed-meson lifetimes are measured to be tau/sub D/ = (8.6 +- 1.3/sub -0.3/ /sup .7/) x 10 T sec, tau/sub D/ = (6.1 +- 0.9 +- 0.3) x 10 T sec, and their ratio tau/sub D/ /tau0 = 1.4 +- 0.3/sub -/ /sub 0.1//sup +0.2/. The total charm cross section at a photon energy of 20 GeV has been measured to be (62 +- 8/sub -/10 V) nb. There is evidence for both DD-barX and D-bar /sub c/ X production with sigma/sub D/ /sub c/ X/sigma/sub charm/ = (71 +- 11 +- 6)%.

• Research Organization: Birmingham University, Birmingham, B15 2TT; United Kingdom Brown University, Providence, Rhode Island 02912; Imperial College, London, SW7 2BZ, United Kingdom; Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830
• DOE Contract Number: AC03-76SF00515
• OSTI ID: 6174368
• Journal Information: Phys. Rev. D; (United States), Journal Name: Phys. Rev. D; (United States) Vol. 33:1; ISSN PRVDA
• Country of Publication: United States
• Language: English

Related Subjects

645101* -- High Energy Physics-- Particle Interactions & Properties-Experimental-- Electromagnetic Interactions & Properties
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BACKSCATTERING
BASIC INTERACTIONS
BOSONS
BUBBLE CHAMBERS
CHARM PARTICLES
CHERENKOV COUNTERS
CROSS SECTIONS
ELECTROMAGNETIC INTERACTIONS
ELEMENTARY PARTICLES
ELEMENTS
ENERGY RANGE
GAS TRACK DETECTORS
GEV RANGE
GEV RANGE 10-100
HADRONS
HYDROGEN
INTERACTIONS
LIFETIME
MEASURING INSTRUMENTS
MESONS
MULTIWIRE PROPORTIONAL CHAMBERS
NATIONAL ORGANIZATIONS
NONMETALS
PARTICLE PRODUCTION
PHOTOPRODUCTION
PROPORTIONAL COUNTERS
RADIATION DETECTORS
SCATTERING
STANFORD LINEAR ACCELERATOR CENTER
TOTAL CROSS SECTIONS
US DOE
US ERDA
US ORGANIZATIONS