HEPData Search

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Measurement of High-energy Direct Photons in $\psi$ Decays

Abrams, G.S. ; Alam, M.S. ; Blocker, C.A. ; et al.

Phys.Rev.Lett. 44 (1980) 114, 1980.

Inspire Record 142835 DOI 10.17182/hepdata.20729

The inclusive γ and π0 momentum distributions at the ψ have been measured. Using these data and estimates of η production, it is found that (4.1 ± 0.8)% of ψ decays contain a direct photon with energy greater than 60% of the beam energy. The expected momentum distribution for direct photons calculated to lowest order in quantum chromodynamics is qualitatively different from that observed in the data.

1 data table

Table 1

INCLUSIVE PHOTON AND PI0 MOMENTUM DISTRIBUTION.

Direct Photon Production at the $\psi$

Scharre, D.L. ; Alam, M.S. ; Boyarski, A. ; et al.

Phys.Rev.D 23 (1981) 43, 1981.

Inspire Record 153865 DOI 10.17182/hepdata.24079

We present results of a detailed analysis of inclusive direct photon production at the ψ(3095). The direct-photon momentum distribution for x>0.4 is presented and compared with the leading-order quantum-chromodynamic prediction. The total production rate is found to be consistent with theoretical expectations, but the observed momentum distribution is considerably softer. Results of an analysis of some inclusive properties of the hadronic system recoiling against the direct photon are presented. The mean charged-particle and Ks multiplicities are presented as functions of the invariant mass of the hadronic system. These data agree well with the corresponding mean multiplicities measured in e+e− annihilations at center-of-mass energies comparable to the invariant mass of the hadronic system.

4 data tables

Table 1

TOTAL INCLUSIVE PHOTON MOMENTUM SPECTRUM. ERRORS ARE STATISTICAL ONLY.

Table 2

PHOTON SPECTRUM PREDICTED FROM MEASUREMENT OF THE PI0 AND ETA DISTRIBUTIONS. ERRORS INCLUDE BOTH STATISTICAL AND RELATIVE SYSTEMATIC COMPONENTS.

Table 3

INCLUSIVE PI0 MOMENTUM DISTRIBUTION. QUOTED ERRORS ARE STATISTICAL ONLY. OVERALL AND RELATIVE SYSTEMATIC ERRORS ARE LESS THAN 30 PCT AND MAY VARY SLOWLY WITH X.

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Production and Decay of the F Meson in $e^+ e^-$ Annihilation at 10-{GeV} Center-of-mass Energy

The ARGUS collaboration Albrecht, H. ; Binder, U. ; Drews, G. ; et al.

Phys.Lett.B 153 (1985) 343, 1985.

Inspire Record 207949 DOI 10.17182/hepdata.30425

Using the ARGUS detector at DORIS, we have observed the production of F ± mesons in e + e − annihilation at a centre of mass energy of 10 GeV through their subsequent decays into φπ ± and φπ + π − π ± . The values obtained for [ R (e + e − →FX). Branching Ratio] are (1.47 ± 0.32 ± 0.20)% and (1.63 ± 0.42 ± 0.41)% respectively. The observed mass is (1973.6 ± 2.6 ± 3.0) MeV c 2 . The F momentum spectrum is as expected for the fragmentation of c quarks into charmed mesons, but is somewhat softer than for fragmentation into D ∗ mesons. The relevant angular distributions are consistent with a spin-zero assignment of the F meson.

2 data tables

Table 1

RESULTS OF FITS FOR SPECIFIED DECAY CHANNELS.

Table 2

ACCEPTANCE CORRECTED FRAGMENTATION FUNCTION FOR THE TWO DECAY CHANNELS COMBINED. X IS PF/PMAX. DATA HAVE BEEN READ FROM THE GRAPH.

Observation of a New Charmed Meson.

The ARGUS collaboration Albrecht, H. ; Binder, U. ; Harder, G. ; et al.

Phys.Rev.Lett. 56 (1986) 549, 1986.

Inspire Record 222219 DOI 10.17182/hepdata.20225

Using the ARGUS detector at the DORIS II e+e− storage ring at DESY, we have obtained evidence for a new charmed resonance which decays into D*±(2010)π∓. The observed mass and width are 2420±6 MeV/c2 and 70±21 MeV/c2, respectively. The fragmentation function is found to be hard, as expected for a state containing a leading charm quark produced by nonresonant e+e− annihilation.

2 data tables

Table 1

No description provided.

Table 2

Estimated production cross section obtained by comparison with observed D*(2010) production rate.

Observation of the Charmed Baryon $\Lambda(c$) in $e^+ e^-$ Annihilation at 10-{GeV}

The ARGUS collaboration Albrecht, H. ; Bockmann, P. ; Glaser, R. ; et al.

Phys.Lett.B 207 (1988) 109-114, 1988.

Inspire Record 260826 DOI 10.17182/hepdata.29980

Using the ARGUS detector at DORIS II, we have studied the production of the charmed baryon Λ c in e + e − annihilation at centre-of-mass energies near 10 GeV. The Λ c + was seen in the three decay modes pK − π + , Λπ + π − π + and K̄ 0 p, with products of normalized cross section times branching ratio [ R ·Br] of (10.8±1.4±1.2)×10 −3 , 6.6±1.5±0.9)×10 −3 and (6.7±1.4±0.8)×10 −3 respectively. The measured mass for the Λ c was (2283.1±1.7±2.0) MeV/ c 2 . A limit on the decay rates to Λπ + is reported. The fragmentation function of the Λ c was measured.

2 data tables

Table 1

Data requested from authors.

Table 2

No description provided.

Study of Hadronic Decays of the $\Z^0$ Boson

The DELPHI collaboration Aarnio, P. ; Abreu, P. ; Adam, W. ; et al.

Phys.Lett.B 240 (1990) 271-282, 1990.

Inspire Record 294894 DOI 10.17182/hepdata.49562

Hadronic decays of Z 0 bosons are studied in the Delphi detector. Global event variables and singel particles inclusive distributions are compared with QCD-based predictions. The mean charged multiplicity is found to be 20.6±1.0 (stat+syst). The mean values of the sphericity, aplanarity, thrust, minor value, p in T and p out T are compared with values found at lower energy e + e − colliders.

13 data tables

Table 1

Corrected Sphericity distribution. Statistical errors only.

Table 2

Corrected Aplanarity distribution. Statistical errors only.

Table 3

Corrected Q3-Q2 distribution. Statistical errors only.

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Measurement of three jet distributions sensitive to the gluon spin in e+ e- annihilations at S**(1/2) = 91-GeV

The OPAL collaboration Alexander, G. ; Allison, John ; Allport, P.P. ; et al.

Z.Phys.C 52 (1991) 543-550, 1991.

Inspire Record 317142 DOI 10.17182/hepdata.14852

None

4 data tables

Table 1

Data at Parton level.

Table 2

Ratio data/(Monte Carlo) at Parton level.

Table 3

Data at Parton level.. Distribution of Ellis-Karliner angle.

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Properties of hadronic Z decays and test of QCD generators

The ALEPH collaboration Buskulic, D. ; Decamp, D. ; Goy, C. ; et al.

Z.Phys.C 55 (1992) 209-234, 1992.

Inspire Record 334577 DOI 10.17182/hepdata.1420

Distributions are presented of event shape variables, jet roduction rates and charged particle momenta obtained from 53 000 hadronicZ decays. They are compared to the predictions of the QCD+hadronization models JETSET, ARIADNE and HERWIG, and are used to optimize several model parameters. The JETSET and ARIADNE coherent parton shower (PS) models with running αs and string fragmentation yield the best description of the data. The HERWIG parton shower model with cluster fragmentation fits the data less well. The data are in better agreement with JETSET PS than with JETSETO(αS2) matrix elements (ME) even when the renormalization scale is optimized.

41 data tables

Table 1

Sphericity distribution.

Table 2

Sphericity distribution.

Table 3

Aplanarity distribution.

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rivet Analysis
A Measurement of D meson production in Z0 hadronic decays

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.

Z.Phys.C 59 (1993) 533-546, 1993.

Inspire Record 356732 DOI 10.17182/hepdata.14375

A study of the fragmentation properties of charm and bottom quarks intoD mesons is presented. From 263 700Z0 hadronic decays collected in 1991 with the DELPHI detector at the LEP collider,D0,D+ andD*+ are reconstructed in the modesK−π+,K−π+K+ andD0π+ followed byD0→K−π+, respectively. The fractional decay widths$\Gamma {{(Z^0\to {D \mathord{\left/ {\vphantom {D {\bar D}}} \right. \kern-\nulldelimiterspace} {\bar D}}X)} \mathord{\left/ {\vphantom {{(Z^0\to {D \mathord{\left/ {\vphantom {D {\bar D}}} \right. \kern-\nulldelimiterspace} {\bar D}}X)} {\Gamma _h }}} \right. \kern-\nulldelimiterspace} {\Gamma _h }}$ are determined, and first results are presented for the production ofD mesons from$c\bar c$ and$b\bar b$ events separately. The average energy fraction ofD*± in charm quark fragmentation is found to be 〈XE(D*)〉c=0.487±0.015 (stat)±0.005 (sys.). Assuming that the fraction ofDs and charm-baryons produced at LEP is similar to that around 10 GeV, theZ0 partial width into charm quark pairs is determined to beΓc/Γh=0.187±0.031 (stat)±0.023 (sys). The probability for ab quark to fragment into$\bar B_s $ orb-baryons is inferred to be 0.268±0.094 (stat)±0.100 (sys) from the measured probability that it fragments into a$\bar B^0 $ orB−.

6 data tables

Table 1

Using full data sample.

Table 2

Using full data sample with proper time > 1 ps to enrich (b bbar) content.

Table 3

Data with Delta(L) > 1.