Date

A study of the energy evolution of event shape distributions and their means with the DELPHI detector at LEP.

The DELPHI collaboration Abdallah, J. ; Abreu, P. ; Adam, W. ; et al.
Eur.Phys.J.C 29 (2003) 285-312, 2003.
Inspire Record 620250 DOI 10.17182/hepdata.13029

Infrared and collinear safe event shape distributions and their mean values are determined in e+e- collisions at centre-of-mass energies between 45 and 202 GeV. A phenomenological analysis based on power correction models including hadron mass effects for both differential distributions and mean values is presented. Using power corrections, alpha_s is extracted from the mean values and shapes. In an alternative approach, renormalisation group invariance (RGI) is used as an explicit constraint, leading to a consistent description of mean values without the need for sizeable power corrections. The QCD beta-function is precisely measured using this approach. From the DELPHI data on Thrust, including data from low energy experiments, one finds beta_0 = 7.86 +/- 0.32 for the one loop coefficient of the beta-function or, assuming QCD, n_f = 4.75 +/- 0.44 for the number of active flavours. These values agree well with the QCD expectation of beta_0=7.67 and n_f=5. A direct measurement of the full logarithmic energy slope excludes light gluinos with a mass below 5 GeV.

71 data tables

1-THRUST distribution.

THRUST-MAJOR distribution.

THRUST-MINOR distribution.

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Measurements of inelastic J/psi and psi' photoproduction at HERA.

The ZEUS collaboration Chekanov, S. ; Krakauer, D. ; Magill, S. ; et al.
Eur.Phys.J.C 27 (2003) 173-188, 2003.
Inspire Record 601166 DOI 10.17182/hepdata.46546

The cross sections for inelastic photoproduction of J/psi and psi' mesons have been measured in ep collisions with the ZEUS detector at HERA, using an integrated luminosity of 38.0 pb-1. The events were required to have 0.1 < z < 0.9 and 50 < W < 180 GeV, where z is the fraction of the incident photon energy carried by the J/psi in the proton rest frame and W is the photon-proton centre-of-mass energy. The psi' to J/psi cross-section ratio was measured in the range 0.55 < z < 0.9. The J/psi data, for various ranges of transverse momentum, are compared to theoretical models incorporating colour-singlet and colour-octet matrix elements. Predictions of a next-to-leading-order colour-singlet model give a good description of the data, although there is a large normalisation uncertainty. The J/psi helicity distribution for z > 0.4 is compared to leading-order QCD predictions.

10 data tables

Measurment of the total cross section, with various PT thresholds, in the high Z > 0.9 region.

Ratio of cross section for PSI(2S) to J/PSI production. as a function of PT. Statistical errors only.

Ratio of cross section for PSI(2S) to J/PSI production. as a function of W. Statistical errors only.

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Differential cross sections, charge production asymmetry, and spin-density matrix elements for D*(2010)+- produced in 500-GeV/c pi- nucleon interactions.

The Fermilab E791 collaboration Aitala, E.M ; Amato, S ; Anjos, J.C ; et al.
Phys.Lett.B 539 (2002) 218-226, 2002.
Inspire Record 587686 DOI 10.17182/hepdata.42892

We report differential cross sections for the production of D*(2010) produced in 500 GeV/c pi^- nucleon interactions from experiment E791 at Fermilab, as functions of Feynman-x (x_F) and transverse momentum squared (p_T^2). We also report the D* +/- charge asymmetry and spin-density matrix elements as functions of these variables. Investigation of the spin-density matrix elements shows no evidence of polarization. The average values of the spin alignment are \eta= 0.01 +- 0.02 and -0.01 +- 0.02 for leading and non-leading particles, respectively.

8 data tables

Acceptance corrected differential cross sections for D*+- production as a function of XL, Feynman X.

Acceptance corected differential cross sections for D*+- production as a function of PT**2.

Charge production asymmetry as a function of Feynman X.

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K*(892)0 production in relativistic heavy ion collisions at S(NN)**(1/2) = 130-GeV.

The STAR collaboration Adler, C. ; Ahammed, Z. ; Allgower, C. ; et al.
Phys.Rev.C 66 (2002) 061901, 2002.
Inspire Record 587235 DOI 10.17182/hepdata.54898

We report the first observation of $K^{\star}(892)^{0}\to\pi K$ in relativistic heavy ion collisions. The transverse momentum spectrum of $(K^{\star0}+\bar{K}^{\star0})/2$ from central Au+Au collisions at $\sqrt{s_{_{NN}}}=130$ GeV is presented. The ratios of the $K^{\star0}$ yield derived from these data to the yields of negative hadrons, charged kaons, and $\phi$ mesons have been measured in central and minimum bias collisions and compared with model predictions and comparable $e^{+}e^{-}$, $pp$, and $\bar{p}p$ results. The data indicate no dramatic reduction of $K^{\star0}$ production in relativistic heavy ion collisions despite expected losses due to rescattering effects.

4 data tables

Transverse mass spectrum of K*0 with YRAP = -0.5 to 0.5 for the 14 PCT most central interactions. Numerical values requested from the authors.

K*0 to negative hadron ratio using hadron data from Adler et al PRL 87,112303(2001).

K*0 to kaon ratio using STAR kaon data.

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A study of strange particle production in nu/mu charged current interactions in the NOMAD experiment.

The NOMAD collaboration Astier, P. ; Autiero, D. ; Baldisseri, A. ; et al.
Nucl.Phys.B 621 (2002) 3-34, 2002.
Inspire Record 566751 DOI 10.17182/hepdata.48925

A study of strange particle production in muon neutrino charged current interactions has been performed using the data from the NOMAD experiment. Yields of neutral strange particles K0s, Lambda, AntiLambda have been measured. Mean multiplicities are reported as a function of the event kinematic variables Enu, W2 and Q2 as well as of the variables describing particle behaviour within a hadronic jet: xF, z and pT2. Decays of resonances and heavy hyperons with identified K0s and Lambda in the final state have been analyzed. Clear signals corresponding to K*+-, Sigma*+-, Xi- and Sigma0 have been observed.

20 data tables

Measured yields of the neutral strange particles measured in this analysis.The second line (marked *) is a recalculation taking into account contributions from both primary and secondary V0. The values for K0 are the K0S rates multipl ied by 2.

Measured yields as a function of E, the neutrino energy.

Measured yields as a function of W**2.

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Study of D*+ production in nu/mu charged current interactions in the NOMAD experiment.

The NOMAD collaboration Astier, P. ; Autiero, D. ; Baldisseri, A. ; et al.
Phys.Lett.B 526 (2002) 278-286, 2002.
Inspire Record 567771 DOI 10.17182/hepdata.49701

A search was made among ν μ charged current events collected in the NOMAD experiment for the reaction: ν μ +N→μ − +D ★+ + hadrons ↪ D 0 +π + ↪ K − +π + . A high purity D ★+ sample composed of 35 events was extracted. The D ★+ yield in ν μ charged current interactions was measured to be T =(0.79±0.17(stat.)±0.10(syst.))%. The mean fraction of the hadronic jet energy taken by the D ★+ is 0.67±0.02(stat.)±0.02(syst.). The distributions of the fragmentation variables z, P T 2 and x F for D ★+ are also presented.

5 data tables

Distribution in Feynman X.

Distribution in transverse momentum.

Distribution in fractional energy Z.

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Charged jet evolution and the underlying event in proton - anti-proton collisions at 1.8-TeV

The CDF collaboration Affolder, T. ; Akimoto, H. ; Akopian, A. ; et al.
Phys.Rev.D 65 (2002) 092002, 2002.
Inspire Record 564673 DOI 10.17182/hepdata.42044

The growth and development of “charged particle jets” produced in proton-antiproton collisions at 1.8 TeV  are studied over a transverse momentum range from 0.5 GeV/c to 50 GeV/c. A variety of leading (highest transverse momentum) charged jet observables are compared with the QCD Monte Carlo models HERWIG, ISAJET, and PYTHIA. The models describe fairly well the multiplicity distribution of charged particles within the leading charged jet, the size of the leading charged jet, the radial distribution of charged particles and transverse momentum around the leading charged jet direction, and the momentum distribution of charged particles within the leading charged jet. The direction of the leading “charged particle jet” in each event is used to define three regions of η−φ space. The “toward” region contains the leading “charged particle jet,” while the “away” region, on the average, contains the away-side jet. The “transverse” region is perpendicular to the plane of the hard 2-to-2 scattering and is very sensitive to the “underlying event” component of the QCD Monte Carlo models. HERWIG, ISAJET, and PYTHIA with their default parameters do not describe correctly all the properties of the “transverse” region.

7 data tables

Average number of charged particles as a function of the relative azimuthal angle between the individual charged particle and the overall leading jet angle.

Average scalar PT sum of charged particles as a function of the relative azimuthal angle between the individual charged particle for 3 different lower limits of the leading jet PT. and the overall jet angle.

The average number of toward(DPHI < 60 DEG), transverse (DPHI 60 TO 120 DEG) and away (DPHI > 120 DEG) charged particles as a function of the PT of the leading charged jet. The data in this table are from the Min-Bias events.

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Properties of hadronic final states in diffractive deep inelastic e p scattering at HERA.

The ZEUS collaboration Chekanov, S. ; Derrick, M. ; Krakauer, D. ; et al.
Phys.Rev.D 65 (2002) 052001, 2002.
Inspire Record 560352 DOI 10.17182/hepdata.46869

Characteristics of the hadronic final state of diffractive deep inelastic scattering events, ep -> eXp, were studied in the kinematic range 4 < M_X < 35 GeV, 4 < Q^2 < 150 GeV^2, 70 < W < 250 GeV and 0.0003 < x_pom < 0.03 with the ZEUS detector at HERA using an integrated luminosity of 13.8 pb^{-1}. The events were tagged by identifying the diffractively scattered proton using the leading proton spectrometer. The properties of the hadronic final state, X, were studied in its center-of-mass frame using thrust, thrust angle, sphericity, energy flow, transverse energy flow and ``seagull'' distributions. As the invariant mass of the system increases, the final state becomes more collimated, more aligned and more asymmetric in the average transverse momentum with respect to the direction of the virtual photon. Comparisons of the properties of the hadronic final state with predictions from various Monte Carlo model generators suggest that the final state is dominated by qqg states at the parton level.

16 data tables

Thrust distribution for a DIS hadronic final state mass between 11 and 17.8GeV.

Thrust distribution for a DIS hadronic final state mass between 17.8 and 27.7 GeV.

Sphericity distribution for a DIS hadronic final state mass between 11 and 17.8 GeV.

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Study of the fragmentation of b quarks into B mesons at the Z peak.

The ALEPH collaboration Heister, A. ; Schael, S. ; Barate, R. ; et al.
Phys.Lett.B 512 (2001) 30-48, 2001.
Inspire Record 558327 DOI 10.17182/hepdata.48926

The fragmentation of b quarks into B mesons is studied with four million hadronic Z decays collected by the ALEPH experiment during the years 1991-1995. A semi-exclusive reconstruction of B->l nu D(*) decays is performed, by combining lepton candidates with fully reconstructed D(*) mesons while the neutrino energy is estimated from the missing energy of the event. The mean value of xewd, the energy of the weakly-decaying B meson normalised to the beam energy, is found to be mxewd = 0.716 +- 0.006 (stat) +- 0.006 (syst) using a model-independent method; the corresponding value for the energy of the leading B meson is mxel = 0.736 +- 0.006 (stat) +- 0.006 (syst). The reconstructed spectra are compared with different fragmentation models.

6 data tables

Normalized binned spectra for weakly-decaying (WD) leading (L) B-mesons.

The extracted spectra spectra for weakly-decaying (WD) leading (L) B-mesons.

Statistical error matrix for the Weakly Decaying distribution in units of 10**-6.

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Measurement of azimuthal asymmetries in deep inelastic scattering.

The ZEUS collaboration Breitweg, J. ; Chekanov, S. ; Derrick, M. ; et al.
Phys.Lett.B 481 (2000) 199-212, 2000.
Inspire Record 524911 DOI 10.17182/hepdata.47071

The distribution of the azimuthal angle for the charged hadrons has been studied in the hadronic centre-of-mass system for neutral current deep inelastic positron-proton scattering with the ZEUS detector at HERA. Measurements of the dependence of the moments of this distribution on the transverse momenta of the charged hadrons are presented. Asymmetries that can be unambiguously attributed to perturbative QCD processes have been observed for the first time.

2 data tables

Differential azimuthal angular distributions for different PT cuts.

Mean values of cos(phi) and cos(2pi) as a function of the PT cut.