Nyitrai, G.
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Studies of Jet Production Rates in $e^+ e^-$ Annihilation at $e$({CM}) = 29-{GeV}

Bethke, S. ; Abrams, G. ; Adolphsen, C.E. ; et al.
Z.Phys.C 43 (1989) 325, 1989.
Inspire Record 277772 DOI 10.17182/hepdata.15472

Production rates of multijet hadronic final states are studied ine+e− annihilation at 29 GeV center of mass energy. QCD shower model calculations with exact first order matrix element weighting at the first gluon vertex are capable of reproducing the observed multijet event rates over a large range of jet pair masses. The method used to reconstruct jets is well suited for directly comparing experimental jet rates with parton rates calculated in perturbative QCD. Evidence for the energy dependene of αs is obtained by comparing the observed production rates of 3-jet events with results of similar studies performed at higher center of mass energies.

2 data tables
Table 1

Observed production rates relative to the total hadronic cross section.

Table 2

Production rates corrected for fragmentation, initial state radiation and detector effects.


Dijet Angular Distributions from anti-p p Collisions at s**(1/2) = 1.8-TeV

The CDF collaboration Abe, F. ; Amidei, D. ; Apollinari, G. ; et al.
Phys.Rev.Lett. 62 (1989) 3020-3023, 1989.
Inspire Record 278394 DOI 10.17182/hepdata.20046

We have measured dijet angular distributions at √s =1.8 TeV with the Collider Detector at Fermilab and the Tevatron p¯p Collider and find agreement with leading-order QCD. By comparing the distribution for the highest dijet invariant masses with the prediction of a model of quark compositeness, we set a lower limit on the associated scale parameter Λc at 330 GeV (95% C.L.).

1 data table
Table 1

Numerical values read from figure in preprint.


rivet Analysis
Charged Multiplicity Distributions and Correlations in e+ e- Annihilation at PETRA Energies

The TASSO collaboration Braunschweig, W. ; Gerhards, R. ; Kirschfink, F.J. ; et al.
Z.Phys.C 45 (1989) 193, 1989.
Inspire Record 277658 DOI 10.17182/hepdata.1499

We report on an analysis of the multiplicity distributions of charged particles produced ine+e− annihilation into hadrons at c.m. energies between 14 and 46.8 GeV. The charged multiplicity distributions of the whole event and single hemisphere deviate significantly from the Poisson distribution but follow approximate KNO scaling. We have also studied the multiplicity distributions in various rapidity intervals and found that they can be well described by the negative binomial distribution only for small central intervals. We have also analysed forward-backward multiplicity correlations for different energies and selections of particle charge and shown that they can be understood in terms of the fragmentation properties of the different quark flavours and by the production and decay of resonances. These correlations are well reproduced by the Lund string model.

29 data tables
Table 1

RATIO of MULT/DISPERSION for the whole event to that for the single hemisphere data.

Table 2

Complete event multiplicities.

Table 3

Single hemisphere multiplicities.

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CENTRAL INTERACTIONS OF Ne-22 NUCLEI WITH HEAVY PHOTOEMULSION NUCLEI AT P(0) = 4.1/A-GeV/c

The Alma Ata-Bucharest-Gatchina:Dubna-Dushanbe-Yerevan-Zernograd- Kosice-Cracow-Leningrad-Moscow-Tashkent-Tbilisi-Ulan Bator collaboration Andreeva, N.P. ; Anzon, Z.V. ; Ameeva, B.U. ; et al.
JINR-P1-89-213, 1989.
Inspire Record 281512 DOI 10.17182/hepdata.38837

None

5 data tables
Table 1

NUCLEUS IS NUCLEAR PHOTOEMULSION. EVENT WITH A TOTAL CHARGE OF ALL SPECTATOR FRAGMENTS OF A PROJECTILE = 0.

Table 2

NUCLEUS IS NUCLEAR PHOTOEMULSION. EVENT WITH A TOTAL CHARGET OF ALL SPECTATOR FRAGMENTS OF A PROJECTILE = 1.

Table 3

NUCLEUS IS NUCLEAR PHOTOEMULSION.

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Hyperon Production at 200-{GeV} and 900-{GeV} Center-of-mass Energy

The UA5 collaboration Ansorge, R.E. ; Asman, B. ; Burow, L. ; et al.
Nucl.Phys.B 328 (1989) 36-58, 1989.
Inspire Record 277298 DOI 10.17182/hepdata.33174

The production of Λ 's and Ξ − 's in proton-antiproton collisions at 200 and 900 GeV c.m. energy has been studied using decays observed in the UA5 streamer chambers. The results are compared to previously published 546 GeV data, to results from other experiments, and to four theoretical models. The Λ yield per inelastic event is estimated to be 0.42±0.11 at 200 GeV and 0.66±0.14 at 900 GeV. We find a mean number of Ξ − 's per inelastic collision of 0.03 −0.02 +0.04 at 200 GeV and 0.06 −0.03 +0.05 at 900 GeV. The average transverse momentum of Λ's in the rapidity region | y |⩽2 is found to be 0.80 −0.14 +0.20 GeV/ c at 200 GeV and 0.74±0.09 GeV/ c at 900 GeV. The average transverse momentum of Ξ − 's in the rapidity region | y |⩽3 is estimated to be 0.8 −0.2 +0.4 GeV/ c at 200 GeV and 0.7 −0.1 +0.2 GeV/ c at 900 GeV which is lower than the unexpectedly high value of 1.1±0.2 GeV/ c measured at 546 GeV. The ratio of Ξ − production to Λ production in the region | y |⩽2, p t >1 GeV/ c is 0.07 −0.04 +0.08 at 900 GeV. This value is consistent with the ratio found in e + e − collisions and lower energy pp collisions but lower than the value obtained at 546 GeV. The average particle composition of events at 200 and 900 GeV, estimated using UA5 data, is presented.

9 data tables
Table 1

Corrected lambda transverse momentum distributions. Numerical values supplied by F. Lotse. Data at 546 GeV are taken from an earlier publication - Phys. Rep. 154 (87) 247.

Table 2

Data at 546 GeV are taken from an earlier publication - Phys. Rep. 154 (87) 247.

Table 3

Corrected lambda transverse momentum distributions. Numerical values supplied by F. Lotse. Data at 546 GeV are taken from an earlier publication - Phys. Rep. 154 (87) 247.

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Measurement of $\pi^- p \to \pi^- p \pi^0$ Reaction Near Threshold and Breaking of Chiral Symmetry

The OMICRON collaboration Kernel, G. ; Korbar, D. ; Krizan, P. ; et al.
Phys.Lett.B 225 (1989) 198-202, 1989.
Inspire Record 278272 DOI 10.17182/hepdata.29804

A full-kinematics measurement of the π − p→ π − p π 0 reaction in the incident π − momentum region from 295 to 450 MeV/ c is presented. The measurement was performed with the OMICRON spectrometer at the CERN synchrocyclotron.

1 data table
Table 1

Integrated cross section.


Comparison of Inclusive Fractional Momentum Distributions of Quark and Gluon Jets Produced in $e^+ e^-$ Annihilation

The TASSO collaboration Braunschweig, W. ; Gerhards, R. ; Kirschfink, F.J. ; et al.
Z.Phys.C 45 (1989) 1, 1989.
Inspire Record 277210 DOI 10.17182/hepdata.15299

Inclusive charged particle production ine+e− annihilation into hadrons is studied in terms of the particle fractional momentumxp. Thexp distribution for gluon jets is extracted by comparing two data samples measured in the TASSO detector: nearly symmetric three jet events at centre-of-mass energyW∼35 GeV and two jet events atW∼22 GeV, yielding quark and gluon jets of similar energies (∼11.5 GeV). No significant difference is observed between quark and gluon jets. Monte Carlo models based on parton showers describe the trend and energy variation of the data better than a model with second order matrix element in αs.

3 data tables
Table 1

2 JET data at sqrt(s) = 35 GeV.

Table 2

3 JET data at sqrt(s) = 22 GeV.

Table 3

Gluon jet data at sqrt(s) = 11.5 GeV.


A Measurement of Electroweak Effects in the Reaction $e^+ e^- \to \tau^+ \tau^-$ at 35-{GeV} and 42.4-{GeV}

The TASSO collaboration Braunschweig, W. ; Gerhards, R. ; Kirschfink, F.J. ; et al.
Z.Phys.C 43 (1989) 549, 1989.
Inspire Record 277662 DOI 10.17182/hepdata.15454

We report on total cross section and forward backward charge asymmetry measurements of the reactione+e− → τ+τ− at centre of mass energies of 35.0 GeV and 42.4 GeV using the TASSO detector. Including previous data an analysis in terms of electroweak parameters of the standard model is presented, and lower limits on mass scale parameters of residual contact interactions are given. A combined analysis of electroweak couplings using all our results on leptonic reactionse+e−→l+l− has been performed.

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.


$\Lambda$(c)+ Production and Semileptonic Decay in 29-{GeV} $e^+ e^-$ Annihilation

Klein, S. ; Himel, T. ; Abrams, G.S. ; et al.
Phys.Rev.Lett. 62 (1989) 2444, 1989.
Inspire Record 277034 DOI 10.17182/hepdata.20042

We present results on Λc+ production in 29-GeV e+e− annihilation. The Λc+ are observed via their semileptonic decays to Λe+X and Λμ+X. With radiative corrections, we find σ(e+e−→Λc+X)〉BΛc+→eΛX)= 1.5±0.6±0.5 pb or 0.0038±0.0015±0.0012 Λc+→Λe+X decay per hadronic event, and σ(e+e−Λc+X)B(Λc+→μΛX)= 1.4±1.4±0.4 pb or 0.0035±0.0035±0.0011 Λc+→Λμ+X decay per hadronic event. These results can be used to place constraints on the predictions of various production models.

2 data tables
Table 1

Cross sections * branching ratio for LAMBDA/C+ production in LAMBDA E+ decay channel.

Table 2

Cross sections * branching ratio for LAMBDA/C+ production in LAMBDA MU+ decay channel.


$\tau$ Production and Decay With the Cello Detector at {PETRA}

The CELLO collaboration Behrend, H.J. ; Criegee, L. ; Dainton, J.B. ; et al.
Phys.Lett.B 222 (1989) 163-172, 1989.
Inspire Record 276859 DOI 10.17182/hepdata.29824

The reaction e + e − → τ + τ − has been studied at centre of mass energies between 14.0 and 46.8 GeV with the CELLO detector at the PETRA e + e − collider. We present results for the cross section σ τ and the charge asymmetry A τ . The results are in good agreement with the standard model. We have also measured the topological decay rates BR 1 , BR 3 and BR 5 for the inclusive decay of the τ lepton into one, three and five charge particles. The results confirm and improve earlier CELLO measurements at other energies. We find for the combined values at all energies BR 1 = (84.9 ± 0.4 ± 0.3)%, BR 3 = (15.0 ± 0.4 ± 0.3)% and BR 5 = (0.16 ± 0.13 ± 0.04)%.

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

Corrected for radiative effects and background contributions.