HEPData Search

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rivet Analysis
Multi - Hadronic Events at E(c.m.) = 29-GeV and Predictions of QCD Models from E(c.m.) = 29-GeV to E(c.m.) = 93-GeV

Petersen, A. ; Abrams, G.S. ; Adolphsen, Chris ; et al.

Phys.Rev.D 37 (1988) 1, 1988.

Inspire Record 246184 DOI 10.17182/hepdata.4114

Multihadronic e+e− annihilation events at a center-of-mass energy of 29 GeV have been studied with both the original (PEP 5) Mark II and the upgraded Mark II detectors. Detector-corrected distributions from global shape analyses such as aplanarity, Q2-Q1, sphericity, thrust, minor value, oblateness, and jet masses, and inclusive charged-particle distributions including x, rapidity, p⊥, and particle flow are presented. These distributions are compared with predictions from various multihadron event models which use leading-logarithmic shower evolution or QCD matrix elements at the parton level and string or cluster fragmentation for hadronization. The new generation of parton-shower models gives, on the average, a better description of the data than the previous parton-shower models. The energy behavior of these models is compared to existing e+e− data. The predictions of the models at a center-of-mass energy of 93 GeV, roughly the expected mass of the Z0, are also presented.

74 data tables

Table 1

Aplanarity distribution.

Table 2

QX Distribution(QX=SQRT(3)*(Q3-Q2)).

Table 3

The (Q2-Q1) distribution.

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rivet Analysis
Measurement of the Polarization of $\tau$ Leptons Produced in $e^+ e^-$ Annihilation at $\sqrt{s}=29$-{GeV}

Ford, William T. ; Qi, N. ; Read, Alexander L. ; et al.

Phys.Rev.D 36 (1987) 1971, 1987.

Inspire Record 245571 DOI 10.17182/hepdata.23349

We present measurements of forward-backward energy asymmetries of τ-lepton decay products from the reaction e+e−→τ+τ− in data collected with the MAC detector operating at the SLAC storage ring PEP at a center-of-mass energy of 29 GeV. The energy asymmetries for the decays τ→ντeν¯e, τ→ντμν¯μ, τ→ντπ, and τ→ντρ are interpreted as effects caused by the combination of maximally parity-violating weak τ decays and a longitudinal polarization produced by the interference of electromagnetic and weak processes. From the forward-backward polarization asymmetry AP=(0.06±0.07)×(1±0.011), we determine the coupling-constant product gaegvτ=(0.26 ±0.31)×(1±0.011). Assuming gae=-(1/2 as expected, we find gvτ=(-0.52±0.62)×(1±0.011), consistent with the prediction of the Glashow-Weinberg-Salam model of electroweak interactions. Alternatively, assuming the standard-model prediction of negligible polarization in τ-pair production, the leptonic energy spectra are used to measure the Michel parameter to be 0.79±0.10±0.10, consistent with the V-A hypothesis for the τν¯τ-W vertex.

1 data table

Table 1

No description provided.

Observation of $\Omega^*$- Production in $K^- p$ Interactions at 11-{GeV}/$c$

Aston, D. ; Awaji, N. ; Bienz, T. ; et al.

Phys.Lett.B 194 (1987) 579-585, 1987.

Inspire Record 245802 DOI 10.17182/hepdata.30108

Clear evidence is presented for the production of an Ω ∗− resonance of mass 2253±13 MeV/ c 2 and width 81±38 MeV/ c 2 in K − p interactions at 11 GeV/ c . The state is observed in the Ξ (1530)K̄ decay mode, and the corresponding inclusive cross section is estimated to be 630±180 nb. Comparisons are made with theoretical predictions and with similar states observed inhyperon beam induced data.

1 data table

Table 1

No description provided.

Pion Pair Production in Photon-photon Collisions at Dci

The DM1-DM2 collaboration Ajaltouni, Z. ; Falvard, A. ; Jousset, J. ; et al.

Phys.Lett.B 194 (1987) 573, 1987.

Inspire Record 248992 DOI 10.17182/hepdata.30109

This paper presents experimental results on π + π − production threshold from the collision of quasi-real photons. The data, obtained at the e + e − collider DCI, are a combination of the results from the DM1 and DM2 experiments. Using the e + e − and π + π − production for normalization and cross-checks, we observe a pion pair yield at low invariant mass ( W < 500 MeV/ c 2 ) which is approximately twice the one expected from Born terms.

2 data tables

Table 1

Data read from graph.

Table 2

Data read from graph.

Multiparticle Production in Proton - Nucleus Collisions at 360-{GeV}/$c$ Using the European Hybrid Spectrometer

The EHS-RCBC collaboration Bailly, J.L. ; Banerjee, S. ; Bartl, W. ; et al.

Z.Phys.C 35 (1987) 301, 1987.

Inspire Record 245414 DOI 10.17182/hepdata.15776

360 GeV/c proton interactions with aluminium (Al) and gold (Au) targets are studied using the European Hybrid Spectrometer (EHS) equipped with the Rapid Cycling Bubble Chamber (RCBC). Multiplicities, rapidity distributions and correlations between leading and other produced particles are presented and compared with Monte Carlo calculations based on the multi-chain and Lund models.

1 data table

Table 1

No description provided.

$D$ Meson Production From 400 GeV/$c p p$ Interactions

The LEBC-EHS collaboration Aguilar-Benitez, M. ; Allison, W.W.M. ; Bailly, J.L. ; et al.

Phys.Lett.B 189 (1987) 476, 1987.

Inspire Record 245101 DOI 10.17182/hepdata.12913

We have measured the inclusive production properties of D and D messons produced from pp interactions at s =27.4 GeV . The differential production cross section is well represented by the empirical form d 2 σ d x F d P 2 T = 1 2 [σ ( D / D )(n+1)b](1−|x F |) n exp (−bp 2 T ) with n=4.9 ± 0.5, b=(1.0±0.1)( GeV /c) −2 , and the inclusive D / D cross section σ ( D / D ) is (30.2±3.3) ωb. The QCD fusion model predicts D / D production which is in good agreement with our data except for the magnitude of the cross section which depends sensitively on the assumed mass of the charm quark.

11 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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STUDY OF THE RESONANCE PRODUCTION IN anti-n p INTERACTIONS AT 6.1-GeV/c

The Dubna-Moscow-Bucharest-Kosice-Sofiya collaboration Batyunya, B.V. ; Boguslavsky, I.V. ; Bruncko, D. ; et al.

Sov.J.Nucl.Phys. 47 (1988) 468, 1988.

Inspire Record 246882 DOI 10.17182/hepdata.9876

None

9 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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A Measurement of the Muon Pair Production in $e^+ e^-$ Annihilation at 38.3-{GeV} $\le \sqrt{s} \le$ 46.8-{GeV}

The CELLO collaboration Behrend, H.J. ; Burger, J. ; Criegee, L. ; et al.

Phys.Lett.B 191 (1987) 209-216, 1987.

Inspire Record 244835 DOI 10.17182/hepdata.30180

The e + e − → μ + μ − reaction has been studied at centre of mass energies ranging between 38.3 abd 46.8 GeV with the CELLO detector at PETRA. We present results on the cross section and the charge asymmetry for this channel. Combining all the data at the average energy 〈 s 〉=43 GeV we obtain R μμ =〈 σ μμ / σ 0 〉=0.98±0.04±0.04, 〈 A μμ 〉=(−14.1±3.7±1.0)%, where σ 0 is the QED cross section and A μμ is the charge asymmetry corrected for pure radiative effects. These results are in good agreement with the expected values of R μμ =1.01 and A μμ =−14.5% at that energy.

3 data tables

Table 1

Mu-pair cross sections.

Table 2

Corrected angular distributions with data sample divided into two energy regions with means 39 and 44 GeV and total energy region.

Table 3

Forward-backward asymmetry.