HEPData Search

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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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PROMPT ELECTRON PRODUCTION IN e+ e- ANNIHILATIONS AT 29-GeV

The TPC/Two Gamma collaboration Aihara, H. ; Alston-Garnjost, M. ; Badtke, D.H. ; et al.

Z.Phys.C 27 (1985) 39, 1985.

Inspire Record 200040 DOI 10.17182/hepdata.1895

We have measured the inclusive prompt electron cross section over a wide momentum range (P>0.5 GeV/c) with the PEP-4 TPC detector. The semielectronic branching fractions of thec andb quarks are (9.1±0.9 (stat.)±1.3 (syst.))% and (11.0±1.8±1.0)%, respectively. Theb quark fragmentation function peaks at highz with 〈zb〉=0.74±0.05±0.03. The axial couplings to the neutral current areac=2.3±1.4±1.0 for thec quark andab=−2.0±1.9±0.5 for theb quark.

3 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

Inclusion of a deuteron triton component in the energy spectra of slow particles in high-energy proton - nucleus interactions

Atageldeva, U.S. ; Dubovichenko, S.B. ; Spitsyna, S.A. ; et al.

Sov.J.Nucl.Phys. 48 (1988) 1038-1042, 1988.

Inspire Record 457322 DOI 10.17182/hepdata.2240

None

3 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

Longitudinal flow from 2-A-GeV to 8-A-GeV Au + Au collisions at the Brookhaven AGS.

The E895 collaboration Klay, J.L. ; Ajitanand, N.N. ; Alexander, J.M. ; et al.

Phys.Rev.Lett. 88 (2002) 102301, 2002.

Inspire Record 566271 DOI 10.17182/hepdata.2868

Rapidity distributions of protons from central $^{197}$Au + $^{197}$Au collisions measured by the E895 Collaboration in the energy range from 2 to 8 AGeV at the Brookhaven AGS are presented. Longitudinal flow parameters derived using a thermal model including collective longitudinal expansion are extracted from these distributions. The results show an approximately linear increase in the longitudinal flow velocity, $<\beta\gamma>_{L}$, as a function of the logarithm of beam energy.

93 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Central Collisions of 800-{GeV} Protons With Ag / Br Nuclei in Nuclear Emulsion

The BATON ROUGE-KRAKOW-MOSCOW-TASHKENT collaboration Abduzhamilov, A. ; Barbier, L.M. ; Chernova, L.P. ; et al.

Phys.Rev.D 39 (1989) 86-91, 1989.

Inspire Record 280844 DOI 10.17182/hepdata.3813

Central collisions of 800-GeV protons with the heavy components of nuclear emulsion, Ag107 and Br80, have been investigated to determine the characteristics of small-impact-parameter collisions and, by comparison with the analysis of inclusive proton-emulsion inelastic interactions and inelastic proton-nucleon collisions, to study the dependence of the interaction process on the mean number of intranuclear collisions 〈ν〉. The data are also compared with the results obtained in proton-emulsion collisions, both central and inclusive, at 200 GeV. The variations in the secondary-particle multiplicities and the normalized pseudorapidity density correlate with 〈ν〉 and demonstrate that proton-nucleus interactions, both central and inclusive, can be described adequately by the incoherent superposition of proton-nucleon collisions.

5 data tables

Table 1

NUCLEUS IS AVERAGE NUCLEUS OF EMULSION.

Table 2

NUCLEUS IS AVERAGE NUCLEUS OF EMULSION.

Table 3

NUCLEUS IS AVERAGE NUCLEUS OF EMULSION.

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Charged Particle Multiplicity and Angular Distributions in Proton Emulsion Interactions at 800-{GeV}

The BATON ROUGE-CRACOW-MOSCOW-TASHKENT collaboration Abduzhamilov, A. ; Barbier, L. ; Chernova, L.P. ; et al.

Phys.Rev.D 35 (1987) 3537-3540, 1987.

Inspire Record 254225 DOI 10.17182/hepdata.3930

The interaction of 800-GeV protons in nuclear emulsion has been investigated. The multiplicities and angular distributions of charged particles emitted by both the projectile and the target nucleus have been measured for 1718 inelastic events and are compared with the data obtained in proton-emulsion collisions at 67, 200, and 400 GeV. The target excitation is found to be independent of energy while the production of secondary particles continues to increase with incident proton energy.

3 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

Production of Four Prong Final States in Photon-photon Collisions

The TPC/Two Gamma collaboration Aihara, H. ; Alston-Garnjost, M. ; Avery, R.E. ; et al.

Phys.Rev.D 37 (1988) 28, 1988.

Inspire Record 261630 DOI 10.17182/hepdata.3824

Results are presented on the exclusive production of four-prong final states in photon-photon collisions from the TPC/Two-Gamma detector at the SLAC e+e− storage ring PEP. Measurement of dE/dx and momentum in the time-projection chamber (TPC) provides identification of the final states 2π+2π−, K+K−π+π−, and 2K+2K−. For two quasireal incident photons, both the 2π+2π− and K+K−π+π− cross sections show a steep rise from threshold to a peak value, followed by a decrease at higher mass. Cross sections for the production of the final states ρ0ρ0, ρ0π+π−, and φπ+π− are presented, together with upper limits for φρ0, φφ, and K*0K¯ *0. The ρ0ρ0 contribution dominates the four-pion cross section at low masses, but falls to nearly zero above 2 GeV. Such behavior is inconsistent with expectations from vector dominance but can be accommodated by four-quark resonance models or by t-channel factorization. Angular distributions for the part of the data dominated by ρ0ρ0 final states are consistent with the production of JP=2+ or 0+ resonances but also with isotropic (nonresonant) production. When one of the virtual photons has mass (mγ2=-Q2≠0), the four-pion cross section is still dominated by ρ0ρ0 at low final-state masses Wγγ and by 2π+2π− at higher mass. Further, the dependence of the cross section on Q2 becomes increasingly flat as Wγγ increases.

12 data tables

Table 1

UNTAGGED DATA.

Table 2

TAGGED DATA, RESULTS OBTAINED USING TRANSVERSE-TRANSVERSE LUMINOSITY ONLY. DATA FOR Q2=0 ARE FROM UNTAGGED SAMPLE, ERRORS DUE TO RELATIVE NORMALISATION OF THESE SAMPLES IS INCLUDED INTO ERRORS QUOTED.

Table 3

UNTAGGED DATA.