The inclusive and semi-inclusive cross sections for K*±(890) and Σ±(1385) resonances are determined in p¯p interactions at 14.75 GeV/c. They account for a large fraction of the KS0 and Λ0 produced. The K*-resonance production also affects the low-pT2 distribution of inclusive KS0. The x distributions of the resonance production are studied in terms of a simple quark-recombination model.
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Average charged multiplicities have been measured separately in $b$, $c$ and light quark ($u,d,s$) events from $Z~0$ decays measured in the SLD experiment. Impact parameters of charged tracks were used to select enriched samples of $b$ and light quark events, and reconstructed charmed mesons were used to select $c$ quark events. We measured the charged multiplicities: $\bar{n}_{uds} = 20.21 \pm 0.10 (\rm{stat.})\pm 0.22(\rm{syst.})$, $\bar{n}_{c} = 21.28 \pm 0.46(\rm{stat.}) ~{+0.41}_{-0.36}(\rm{syst.})$ $\bar{n}_{b} = 23.14 \pm 0.10(\rm{stat.}) ~{+0.38}_{-0.37}(\rm{syst.})$, from which we derived the differences between the total average charged multiplicities of $c$ or $b$ quark events and light quark events: $\Delta \bar{n}_c = 1.07 \pm 0.47(\rm{stat.})~{+0.36}_{-0.30}(\rm{syst.})$ and $\Delta \bar{n}_b = 2.93 \pm 0.14(\rm{stat.})~{+0.30}_{-0.29}(\rm{syst.})$. We compared these measurements with those at lower center-of-mass energies and with perturbative QCD predictions. These combined results are in agreement with the QCD expectations and disfavor the hypothesis of flavor-independent fragmentation.
Average charge multiplicity in B-tagged events.
Average charge multiplicity in C-tagged events.
Average charge multiplicity in light quark (uds) events.
Using the Belle detector operating at the KEKB e+e- storage ring, we have measured the mean multiplicity and the momentum spectrum of neutral pions from the decays of the Upsilon(4S) resonance. We measure a mean of 4.70 +/- 0.04 +/- 0.22 neutral pions per Upsilon(4S) decay.
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An experimental study of b-quark jets using high- p T electrons was carried out at √ s =58 GeV with the TOPAZ detector at the e + e − collider TRISTAN at KEK. The forward-backward charge asymmetry of the b-quark was obtained to be A b b ̄ =−0.55±0.27( stat. )±0.07( syst. ) , consistent with the standard model prediction. Also, such jet properties of the b-quark as the average charged multiplicity and the rapidity of charged particles were analyzed. In order to purify the b-quark event samples in this analysis, only events with backward-going electrons or forward-going positrons were used. The energy dependence of these jet properties was studied by making comparisons with the results of the DELCO experiment at the PEP collider (√ s =29 GeV) at SLAC.
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Mean values of jet properties for b-jet sample.
Results are presented on the charge exchange reaction\(\bar pp \to \bar nn\) and\(\bar np\) annihilations from bubble chamber exposures to antiproton beam of momenta 700 and 760 MeV/c. The differential cross section of\(\bar pp \to \bar nn\) shows a forward spike followed by a clear dip bump structure. Total annihilation cross section of\(\bar np\) for average\(\bar n\) momentum of 700 MeV/c has been evaluated to be 55.4±2.2 mb. The multiplicity, Feynmanx andpT2 distributions for inclusive charged pions in\(\bar pp\) and\(\bar np\) annihilations are found to be similar. The emission of charged pions from\(\bar np\) annihilations are found to be consistent with thermodynamic models with temperature ∼110 MeV.
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Using data obtained with EHS equipped with the Rapid Cycling Bubble Chamber (RCBC) exposed to a proton beam of 360 GeV/c, we calculate topological cross sections. We present in great detail the procedure and the techniques used to correct raw data. Finally, we give multiplicity moments and multiplicity correlations and we compare the values obtained in our experiment, together with data at other energies, with different models.
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Results are reported concerning the charged-particle multiplicity distribution obtained in an exposure of the high-resolution hydrogen bubble chamber LEBC to a beam of 800 GeV protons at the Fermilab MPS. This is the first time that such data have been available at this energy. The distribution of the number n ch of charged particles produced in inelastic interactions obeys KNO-scaling. The average multiplicity is 〈 n ch 〉 = 10.26±0.15. For n ch ⩾8 the data can be well fitted to a negative binomial. The difference between the overall experimental multiplicity distribution and that resulting from the latter fit is in agreement with the contribution expected from diffractive processes.
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Results on inclusive K s 0 production in e + e − annihilation at mean center-of-mass energies of 9.4, 12.0 and 30 GeV are presented. The ratio R (K 0 ) = 2 σ (K s 0 )/ σ μμ rises from 3.10 ± 0.75 at √ s = 9.4 GeV to 5.6 ± 1.2 at √ s = 30 GeV, corresponding to an approximately constant K 0 /charged-particle ratio of 0.12 ± 0.02. A similar ratio for K 0 / charged particle is observed for direct hadronic decays of the ϒ.
SYSTEMATIC ERROR INCLUDED.
NUMBER OF K0 PER HADRONIC EVENT. AUTHORS ALSO USE MULTIPLICITY TO ESTIMATE NUMBER OF K0 PER CHARGED PARTICLE.
INCLUDING EARLIER DATA.
Inclusive production of ifπ ± , K ± and p has been studied near charm threshold for c.m. energies between 3.6 and 5.2 GeV. Differential and scaling cross sections together with particle multiplicities have been determinated. By comparing data below and above charm threshold the charm contribution to if π ± and K ± production has been extracted. A comparison has been made between inclusice p production and inelastic electron-proton scattering. To study differences between three-gluon annihilation and two-quark production of the spectra from J/ decay and from non-resonant production at 3.6 GeV has been compared.
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