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rivet Analysis
Delta++ production in hadronic Z0 decays

The OPAL collaboration Alexander, G. ; Allison, John ; Altekamp, N. ; et al.

Phys.Lett.B 358 (1995) 162-172, 1995.

Inspire Record 398320 DOI 10.17182/hepdata.48153

The production of Δ ++ baryons has been measured using 3.5 million hadronic Z 0 decays collected with the OPAL detector at LEP. The production rate and fragmentation function are presented. A total of 0.22 ± 0.04 ± 0.04 Δ ++ + ( Δ ) −− per hadronic Z 0 decay is observed. The fragmentation function is found to be softer than that predicted by the JETSET and HERWIG Monte Carlo event generators. With this measurement of Δ ++ production, at least one baryon of each strangeness level in the lightest baryon decuplet has now been measured at LEP.

1 data table

Table 1

No description provided.

Study of prompt photon production in hadronic Z0 decays

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

Z.Phys.C 69 (1995) 1-14, 1995.

Inspire Record 397391 DOI 10.17182/hepdata.48136

None

3 data tables

Table 1

Rates for gamma + 1 jet.

Table 2

Rates for gamma + 2 jet.

Table 3

Rates for gamma + 3 jet.

A Measurement of the tau leptonic branching fractions

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

Phys.Lett.B 357 (1995) 715-724, 1995.

Inspire Record 398321 DOI 10.17182/hepdata.48138

A sample of 25000 Z 0 → τ + τ − events collected by the DELPHI experiment at LEP in 1991 and 1992 is used to measure the leptonic branching fractions of the τ lepton. The results are B(τ → eν ν ) = (17.51 ± 0.39) % and B(τ → μν ν ) = (17.02 ± 0.31) %. The ratio of the muon and electron couplings to the weak charged current is measured to be g μ g e = 1.000 ± 0.013 , satisfying e-μ universality. The leptonic branching fraction corrected to the value for a massless lepton, assuming e-μ universality, is found to be B(τ → lν ν ) = (17.50 ± 0.25) %.

3 data tables

Table 1

Axis error includes +- 0.23/0.23 contribution (Data statistics).

Table 2

Axis error includes +- 0.19/0.19 contribution (Data statistics).

Table 3

Combined from the two branching fractions above. E-MU universality assumed.

Measurement of the average b baryon lifetime and the product branching ratio f (b --> Lambda(b)) x BR (Lambda(b) --> Lambda lepton- anti-neutrino X)

The OPAL collaboration Akers, R. ; Alexander, G. ; Allison, John ; et al.

Z.Phys.C 69 (1996) 195-214, 1996.

Inspire Record 397395 DOI 10.17182/hepdata.51966

None

1 data table

Table 1

Charged conjugate state is assumed.

Search for exclusive charmless B meson decays with the DELPHI detector at LEP

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

Phys.Lett.B 357 (1995) 255-266, 1995.

Inspire Record 397145 DOI 10.17182/hepdata.52353

Charmless hadronic decays of beauty mesons have been searched for using the data collected with the DELPHI detector at the LEP collider. Several two, three and four-body decay modes have been investigated. Particle identification was used to distinguish the final states with protons, kaons and pions. Three candidate events selected in two-body decay modes are interpreted as evidence for charmless B decays. No excess has been found in higher multiplicity modes and improved upper limits for some of the branching ratios are given.

3 data tables

Table 1

Two body decay modes. Upper limits at 90% CL. In computing of limits the fractions of B/(d,u)(0,-) and B/S0 mesons were assumed to be 0.39 and 0.12 respectively. Limits are given for the weighted average of the decay rates of the two neutral B mesons.

Table 2

Three body decay modes. Upper limits at 90% CL.

Table 3

Four body decay modes. Upper limits at 90% CL.

A Measurement of the photon structure function F2(gamma) at an average Q2 of 12-GeV2/c**4

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

Z.Phys.C 69 (1996) 223-234, 1996.

Inspire Record 396884 DOI 10.17182/hepdata.47867

None

2 data tables

Table 1

No description provided.

Table 2

Low x domain.

W and Z boson production in p anti-p collisions at s**(1/2) = 1.8-TeV

The D0 collaboration Abachi, S. ; Abbott, B. ; Abolins, M. ; et al.

Phys.Rev.Lett. 75 (1995) 1456-1461, 1995.

Inspire Record 395459 DOI 10.17182/hepdata.42368

The inclusive cross sections times leptonic branching ratios for W and Z boson production in PbarP collisions at Sqrt(s)=1.8 TeV were measured using the D0 detector at the Fermilab Tevatron collider: Sigma_W*B(W->e, nu) = 2.36 +/- 0.07 +/- 0.13 nb, Sigma_W*B(W->mu,nu) = 2.09 +/- 0.23 +/- 0.11 nb, Sigma_Z*B(Z-> e, e) = 0.218 +/- 0.011 +/- 0.012 nb, Sigma_Z*B(Z->mu,mu) = 0.178 +/- 0.030 +/- 0.009 nb. The first error is the combined statistical and systematic uncertainty, and the second reflects the uncertainty in the luminosity. For the combined electron and muon analyses we find: [Sigma_W*B(W->l,nu)]/[Sigma_Z*B(Z->l,l)] = 10.90 +/- 0.49. Assuming Standard Model couplings, this result is used to determine the width of the W boson: Gamma(W) = 2.044 +/- 0.093 GeV.

1 data table

Table 1

The second DSYS error is due to luminosity.

A Study of the strong coupling constant using W + jets processes

The D0 collaboration Abachi, S. ; Abbott, B. ; Abolins, M. ; et al.

Phys.Rev.Lett. 75 (1995) 3226-3231, 1995.

Inspire Record 394610 DOI 10.17182/hepdata.42454

The ratio of the number of W+1 jet to W+0 jet events is measured with the D0 detector using data from the 1992–93 Tevatron Collider run. For the W→eν channel with a minimum jet ET cutoff of 25 GeV, the experimental ratio is 0.065±0.003stat±0.007syst. Next-to-leading order QCD predictions for various parton distributions agree well with each other and are all over 1 standard deviation below the measurement. Varying the strong coupling constant αs in both the parton distributions and the partonic cross sections simultaneously does not remove this discrepancy.

1 data table

Table 1

Two values of ALPHA_S corresponds the two different parton distribution functions (pdf) used in extraction of ALPHA_S from the ratio. The dominant systematic error is from the jet energy scale uncertainty.

Measurement of the longitudinal, transverse and asymmetry fragmentation functions at LEP

The OPAL collaboration Akers, R. ; Alexander, G. ; Allison, John ; et al.

Z.Phys.C 68 (1995) 203-214, 1995.

Inspire Record 395450 DOI 10.17182/hepdata.48040

The fragmentation function for the process e+e−→h+X, whereh represents a hadron, may be decomposed into transverse, longitudinal and asymmetric contributions by analysis of the distribution of polar production angles. A number of new tests of QCD have been proposed using these fragmentation functions, but so far no data have been published on the separate components. We have performed such a separation using data on charged particles from hadronic Z0 decays atOpal, and have compared the results with the predictions of QCD. By integrating the fragmentation functions, we determine the average charged particle multiplicity to be\(\overline {n_{ch} }= 21.05 \pm 0.20\). The longitudinal to total cross-section ratio is determined to be σL/σtot=0.057±0.005. From the longitudinal fragmentation function we are able to extract the gluon fragmentation function. The connection between the asymmetry fragmentation function and electroweak asymmetrics is discussed.

4 data tables

Table 1

Transverse component of the fragmentation function.

Table 2

Longitudinal component of the fragmentation function.

Table 3

Asymmetry component of the fragmentation function.

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