Measurement of {alpha}{sub s} in e{sup +}e{sup {minus}} annihilation at E{sub cm} = 29 GeV

Conference · Fri Jul 01 00:00:00 EDT 1994

OSTI ID:10111912

Bauer, D A; Caldwell, D O ^[1]; Belcinski, R ^[2]; Berg, R C; Buchanan, C D; Chun, S B ^[3]; Bingham, H H ^[4]; Bloom, E D ^[5]

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1. Univ. of California, Santa Barbara, CA (United States)
2. Univ. of Massachusetts, Amherst, MA (United States)
3. Univ. of California, Los Angeles, CA (United States)
4. Univ. of California, Berkeley, CA (United States)
5. Stanford Univ., CA (United States). Stanford Linear Accelerator Center; and others

A measurement of the strong coupling constant {alpha}{sub s} using the event-shape variable y{sub 3} (the differential two-jet rate) in the reaction e{sup +}e{sup {minus}} {yields} hadrons is presented. The analysis is based on data from the TPC/Two-Gamma detector at the PEP e{sup +}e{sup {minus}} storage ring taken between 1984 and 1986 at a center-of-mass energy of E{sub cm} = 29 GeV. A value of {alpha}{sub s}(29 GeV) = 0.160 {+-} 0.012 is obtained, where the error is the quadratic sum of experimental and theoretical uncertainties. The procedure for determining {alpha}{sub s} is the same as that used by the ALEPH and TOPAZ experiments, which allows for a consistent comparison of the {alpha}{sub s} values obtained at different center-of-mass energies. The observed energy dependence {open_quotes}running{close_quotes} of {alpha}{sub s} is found to be in good agreement with the QCD prediction, and is clearly incompatible with a constant value.

• Research Organization: Stanford Linear Accelerator Center, Menlo Park, CA (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States); National Science Foundation, Washington, DC (United States)
• DOE Contract Number: AC03-76SF00515; FG03-91ER40674; AS03-76ER70285; FG03-91ER40662; AT03-87ER40327; AM03-76SF00010; AC03-76SF00098; FG02-92ER40730; FG02-92ER40715
• OSTI ID: 10111912
• Report Number(s): SLAC-PUB-6518; LBL-35812; CONF-940722-41; ON: DE95006486; CNN: Grant PHY91-19849; Grant PHY91-21416; TRN: 95:001616
• Resource Relation: Conference: 27. international conference on high energy physics,Glasgow (United Kingdom),21-27 Jul 1994; Other Information: PBD: Jul 1994
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
STRONG INTERACTIONS
COUPLING CONSTANTS
ELECTRON-POSITRON INTERACTIONS
ANNIHILATION
HADRONS
662230
662310
QUANTUM CHROMODYNAMICS
WEAK AND ELECTROMAGNETIC INTERACTIONS OF LEPTONS