Inclusive production cross sections of $\pi^\pm$, $K^\pm$ and $p\bar{p}$ per hadronic $e^+e^-$ annihilation event in $e^+e^-$ are measured at a center-of-mass energy of 10.54 GeV, using a relatively small sample of very high quality data from the BaBar experiment at the PEP-II $B$-factory at the SLAC National Accelerator Laboratory. The drift chamber and Cherenkov detector provide clean samples of identified $\pi^\pm$, $K^\pm$ and $p\bar{p}$ over a wide range of momenta. Since the center-of-mass energy is below the threshold to produce a $B\bar{B}$ pair, with $B$ a bottom-quark meson, these data represent a pure $e^+e^- \rightarrow q\bar{q}$ sample with four quark flavors, and are used to test QCD predictions and hadronization models. Combined with measurements at other energies, in particular at the $Z^0$ resonance, they also provide precise constraints on the scaling properties of the hadronization process over a wide energy range.
Differential cross section for prompt PI+-, K+- and PBAR/P production.
Differential cross section for conventional PI+-, K+- and PBAR/P production.
Integrated cross sections for prompt PI+-, K+- and PBAR/P production. The second (sys) error is the uncertainty due to the model dependence of the extrapolation.
We present improved measurements of the differential production rates of stable charged particles in hadronic Z0 decays, and of charged pions, kaons and protons identified over a wide momentum range using the SLD Cherenkov Ring Imaging Detector. In addition to flavor-inclusive Z0 decays, measurements are made for Z0 decays into light (u, d, s), c and b primary flavors, selected using the upgraded Vertex Detector. Large differences between the flavors are observed that are qualitatively consistent with expectations based upon previously measured production and decay properties of heavy hadrons. These results are used to test the predictions of QCD in the Modified Leading Logarithm Approximation, with the ansatz of Local Parton-Hadron Duality, and the predictions of three models of the hadronization process. The light-flavor results provide improved tests of these predictions, as they do not include the contribution of heavy-hadron production and decay; the heavy-flavor results provide complementary model tests. In addition we have compared hadron and antihadron production in light quark (as opposed to antiquark) jets. Differences are observed at high momentum for all three charged hadron species, providing direct probes of leading particle effects, and stringent constraints on models.
Production rates of all stable charged particles. The statistical and systematic errors are shown separately for the momentum distribution. They are combined in quadrature for the other two distributions. The first DSYS error is due tothe uncertainty in the track finding efficiency and the second DSYS error is th e rest of the systematic error.
The charged pion fraction and differential production rate per hadronic Z0 decay.
The charged kaon fraction and differential production rate per hadronic Z0 decay.
Inclusive distributions of charged particles in hadronic W decays are experimentally investigated using the statistics collected by the DELPHI experiment at LEP during 1997, 1998 and 1999, at centre-of-mass energies from 183 to around 200 GeV. The possible effects of interconnection between the hadronic decays of two Ws are not observed. Measurements of the average multiplicity for charged and identified particles in q qbar and WW events at centre-of-mass energies from 130 to 200 GeV and in W decays are presented. The results on the average multiplicity of identified particles and on the position xi^* of the maximum of the xi_p = -log(2p/sqrt(s)) distribution are compared with predictions of JETSET and MLLA calculations.
Corrected multiplicites and dispersions of charged particles produced in hadronic decays from QQBAR events. The 200 GeV results are a weighted average fromthe 192, 196 and 200 GeV data.
Average multiplicities of identified hadrons produced in hadronic decays from QQBAR events.
Corrected multiplicites and dispersions of charged particles produced in fully hadronic W decays from two W 4Q and 2Q events.
The DELPHI experiment at LEP uses Ring Imaging Cherenkov detectors for particle identification. The good understanding of the RICH detectors allows the identification of charged pions, kaons and proto
Mean particle multiplicities for Z0-->Q-QBAR events. The second systematic (DSYS) error is due to the extrapolation of the differential distributions to the full kinematic range.
Mean particle multiplicities for Z0-->B-BBAR events. The second systematic (DSYS) error is due to the extrapolation of the differential distributions to the full kinematic range.
Mean particle multiplicities for Z0-->(U-UBAR,D-DBAR,S-SBAR) events. The second systematic (DSYS) error is due to the extrapolation of the differential distributions to the full kinematic range.
Event shape and charged particle inclusive distributions are measured using 750000 decays of the Z to hadrons from the DELPHI detector at LEP. These precise data allow a decisive confrontation with models of the hadronization process. Improved tunings of the JETSET, ARIADNE and HERWIG parton shower models and the JETSET matrix element model are obtained by fitting the models to these DELPHI data as well as to identified particle distributions from all LEP experiments. The description of the data distributions by the models is critically reviewed with special importance attributed to identified particles.
Transverse momentum PTIN w.r.t. the Thrust axis. For the first table Thrust axis definition is from seen charged particles corrected to final state particles. For the second table Thrust axis definition is from seen charged plus neutral particles corrected to final state charged plus neutral particles.
Transverse momentum PTOUT w.r.t. the Thrust axis. For the first table Thrust axis definition is from seen charged particles corrected to final state particles. For the second table Thrust axis definition is from seen charged plus neutral particles corrected to final state charged plus neutral particles.
Transverse momentum PTIN w.r.t. the Sphericity axis. For the first table Sphericity axis definition is from seen charged particles corrected to final state particles. For the second table Sphericity axis definition is from seen charged plus neutral particles corrected to final state charged plus neutral particles.
This analysis, based on a sample of 170000 hadronic Z0 decays, provides a measurement of the K ± and p/ p differential cross sections which is compared to string- and cluster fragmentation models. The total multiplicities for K ± and p/ p per hadronic event were found to be: NK = 2.26 ± 0.18 and N p = 1.07 ± 0.14. The positions ξ * of the maxima of the differential cross sections as a function of ξ = ln(1/ x p ) for K ± and p/ p were determined to be 2.63 ± 0.07 and 2.96 ± 0.16 respectively. A comparison of the ξ * values for various identified particles measured at LEP with the prediction of the Modified Leading Logarithm Approximation with Local Parton Hadron Duality model has been performed. The measured ξ * position as a function of the hadron mass, after corrections due to particle decays, is in agreement with the model calculation.
Second systematic error comes from the extrapolation to the full Z range (measured range is 0.018 < Z < 0.5) using the JETSET prediction.
Second systematic error comes from the extrapolation to the full Z range (measured range is 0.031 < Z < 0.11) using the JETSET prediction.
No description provided.
A sample of events enriched in bb̄ quark pairs was selected in the data recorded by the DELPHI experiment at LEP during 1992 and 1993, by the presence of secondary decay vertices from short-lived particles. Using this sample, the average multiplicities of K s 0 , K ± , p(p̄), Λ( Λ ) and of charged particles in bb̄ events have been measured, distinguishing the component from fragmentation and the component coming from the decay of b-hadrons. The measurement of the average charge multiplicity in bb̄ events was used to compute the mean fractional beam energy carried by the primary b-hadron, and the difference in charged particle multiplicity between bb̄ events and light quark (uū, dd̄, ss̄) events.
Event multiplicity in bottom events.
Differential cross section for charged particles in BOTTOM tagged hemispheres.
Differential cross section for charged particles in untagged hemispheres.
We report measurements of π±K±, and p, p¯ inclusive cross sections and fractions in e+e− annihilation at s=29 GeV, for the momentum interval 0.01
No description provided.
No description provided.
No description provided.
The multiplicities per event of π ± and K ± are measured separately for e + e - annihilation into c c , b b , and light quark pairs at E cm=29 GeV. The K ± multiplicity is higher for heavy quark events than for light quark events. The π ± multiplicity and the π ± scaled differential cross section at low x = E beam/ E beam are found to be higher for b b events than for other events.
Numerical values requested from authors. Data given separately for (b bbar), (c cbar) and light quark jets.
Measured multiplicities for (b bbar) jets.
Measured multiplicities for (c cbar) jets.
Proton production in e+e− annihilation at 29 GeV has been studied with the time projection chamber. Measurements of the dependence of proton fractions on momentum, transverse momentum with respect to the jet axis, hadron multiplicity, and event sphericity are reported. Our results are consistent with the assumption that primary baryons and mesons have similar production spectra, and indicate that protons provide more direct probes of underlying fragmentation phenomena than do pions.
No description provided.
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