Measurement of sigma(p anti-p ---> Z + X) Br(Z ---> tau+tau-) at s**(1/2) = 1.96-TeV

The D0 collaboration Abazov, V.M. ; Abbott, B. ; Abolins, M. ; et al.
Phys.Lett.B 670 (2009) 292-299, 2009.
Inspire Record 792818 DOI 10.17182/hepdata.42676

We present a measurement of the cross section for Z boson production times the branching fraction to tau lepton pairs sigma(ppbar -> Z + X) Br(Z -> tau+ tau-) in proton-antiproton collisions at center of mass energy 1.96 TeV. The measurement is performed in the channel in which one tau lepton decays into a muon and neutrinos, and the other tau lepton decays hadronically or into an electron and neutrinos. The data sample corresponds to an integrated luminosity of 1.0 inverse fb collected with the D0 detector at the Fermilab Tevatron Collider. The sample contains 1511 candidate events with an estimated 20% background from jets or muons misidentified as tau leptons. We obtain sigma Br = 240 +/- 8 (stat) +/- 12 (sys) +/- 15 (lum) pb, which is consistent with the standard model prediction.

1 data table

Measured cross section times branching ratio to TAU+ TAU-.


Observation of the $\phi(1680)$ and the Y(2175) in $e^+ e^- \to \phi\pi^+\pi^-$

The Belle collaboration Shen, C.P. ; Yuan, C.Z. ; Wang, P. ; et al.
Phys.Rev.D 80 (2009) 031101, 2009.
Inspire Record 809630 DOI 10.17182/hepdata.52399

The cross sections for $e^+ e^- \to \phi\pi^+\pi^-$ and $e^+ e^- \to \phi \fzero$ are measured from threshold to $\sqrt{s}=3.0$ $\hbox{GeV}$ using initial state radiation. The analysis is based on a data sample of 673 fb$^{-1}$ collected on and below the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. First measurements are reported for the resonance parameters of the $\phi(1680)$ in the $\phi\pi^+\pi^-$ mode: $m=(1689\pm 7\pm 10)$ MeV/$c^2$ and $\Gamma=(211\pm 14\pm 19)$ MeV/$c^2$. A structure at $\sqrt{s}=2.1 \hbox{GeV}/c^2$, corresponding to the so called Y(2175), is observed/ its mass and width are determined to be $2079\pm13^{+79}_{-28}$ MeV/$c^2$ and $192\pm23^{+25}_{-61} \hbox{MeV}/c^2$, respectively.

2 data tables

Measured E+ E- --> PHI PI+ PI- cross section.

Measured E+ E- --> PHI F0 cross section.


Measurement of differential Z / gamma* + jet + X cross sections in p anti-p collisions at s**(1/2) = 1.96-TeV

The D0 collaboration Abazov, V.M. ; Abbott, B. ; Abolins, M. ; et al.
Phys.Lett.B 669 (2008) 278-286, 2008.
Inspire Record 792812 DOI 10.17182/hepdata.49090

We present new measurements of differential cross sections for Z/gamma*(->mumu)+jet+X production in a 1 fb-1 data sample collected with the D0 detector in proton anti-proton collisions at sqrt{s}=1.96 TeV. Results include the first measurements differential in the Z/gamma* transverse momentum and rapidity, as well as new measurements differential in the leading jet transverse momentum and rapidity. Next-to-leading order perturbative QCD predictions are compared to the measurements, and reasonable agreement is observed, except in the region of low Z/gamma* transverse momentum. Predictions from two event generators based on matrix elements and parton showers, and one pure parton shower event generator are also compared to the measurements. These show significant overall normalization differences to the data and have varied success in describing the shape of the distributions.

6 data tables

Measured cross section as a function of the jet transverse momentum.

Measured cross section as a function of the jet rapidity.

Measured cross section as a function of the Z0 transverse momentum.

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Systematic Measurements of Identified Particle Spectra in pp, d+Au and Au+Au Collisions from STAR

The STAR collaboration Abelev, B.I. ; Aggarwal, M.M. ; Ahammed, Z. ; et al.
Phys.Rev.C 79 (2009) 034909, 2009.
Inspire Record 793126 DOI 10.17182/hepdata.104931

Identified charged particle spectra of $\pi^{\pm}$, $K^{\pm}$, $p$ and $\pbar$ at mid-rapidity ($|y|<0.1$) measured by the $\dedx$ method in the STAR-TPC are reported for $pp$ and d+Au collisions at $\snn = 200$ GeV and for Au+Au collisions at 62.4 GeV, 130 GeV, and 200 GeV. ... [Shortened for arXiv list. Full abstract in manuscript.]

68 data tables

Uncorrected charged particle multiplicity distribution measured in the TPC in $|\eta| < 0.5$ for Au+Au collisions at 62.4 GeV and 200 GeV. The shaded regions indicate the centrality bins used in the analysis. The 200 GeV data are scaled by a factor 5 for clarity.

Uncorrected charged particle multiplicity distribution measured in the TPC in $|\eta| < 0.5$ for Au+Au collisions at 62.4 GeV and 200 GeV. The shaded regions indicate the centrality bins used in the analysis. The 200 GeV data are scaled by a factor 5 for clarity.

Uncorrected charged particle multiplicity distribution measured in the E-FTPC (Au-direction) within $−3.8 < |\eta| < −2.8$ in d+Au collisions at 200 GeV. The shaded regions indicate the centrality bins used in the analysis.

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Di-jet production in gamma-gamma collisions at LEP2

The DELPHI collaboration Abdallah, J. ; Abreu, P. ; Adam, W. ; et al.
Eur.Phys.J.C 58 (2008) 531-541, 2008.
Inspire Record 806241 DOI 10.17182/hepdata.51688

The production of two high-p_T jets in the interactions of quasi-real photons in e+e- collisions at sqrt{s_ee} from 189 GeV to 209 GeV is studied with data corresponding to an integrated e+e- luminosity of 550 pb^{-1}. The jets reconstructed by the k_T cluster algorithm are defined within the pseudo-rapidity range -1 < eta < 1 and with jet transverse momentum, p_T, above 3 GeV/c. The differential di-jet cross-section is measured as a function of the mean transverse momentum ptmean of the jets and is compared to perturbative QCD calculations.

11 data tables

Total cross section for dijet production. Errors are combined statistics and systematics.

Measured dijet production cross section as a function of the mean jet transverse momentum. Errors include both statistics and systematics.

Measured dijet production cross section as a function of jet pseudorapiditydifference. Errors include both statistics and systematics.

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Study of the process e+e- -> omega pi0 in the phi-meson mass region with the KLOE detector

The KLOE collaboration Ambrosino, F. ; Antonelli, A. ; Antonelli, M. ; et al.
Phys.Lett.B 669 (2008) 223-228, 2008.
Inspire Record 791841 DOI 10.17182/hepdata.50498

We have studied the e+e- -> omegapi0 cross section in the sqrt(s) interval 1000-1030 MeV using the pi+pi-pi0pi0 and pi0pi0gamma final states with a sample of ~600 pb^-1 collected with the KLOE detector at DAFNE. By fitting the observed interference pattern around M_phi for both final states, we extract the ratio of the decay widths Gamma(omega->pi0gamma)/Gamma(omega->pi+pi-pi0) = 0.0897 +- 0.0016 and derive the branching fractions BR(omega -> pi+pi-pi0)= (90.24 +- 0.19)%, BR(omega -> pi0gamma) = (8.09 +- 0.14)%. The parameters describing the e+e- -> omegapi0 reaction around M_\phi are also used to extract the branching fraction for the OZI and G-parity violating phi -> omegapi0 decay: BR(phi->omegapi0) = (4.4 +- 0.6)x10^-5.

2 data tables

Axis error includes +- 0.75/0.75 contribution.

Axis error includes +- 0.6/0.6 contribution.


Near threshold production of the eta meson via the quasi-free pn --> pn eta reaction

Moskal, P. ; Czyzykiewicz, R. ; Adam, H.-H. ; et al.
Phys.Rev.C 79 (2009) 015208, 2009.
Inspire Record 789961 DOI 10.17182/hepdata.50529

Total cross sections for the quasi-free pn --> pn eta reaction in the range from the kinematical threshold up to 20 MeV excess energy have been determined. At threshold they exceed corresponding cross sections for the pp --> pp eta reaction by a factor of about three in contrast to the factor of six established for higher excess energies. To large extent, the observed decrease of the ratio sigma(pn --> pn eta)/sigma(pp --> pp eta) towards threshold may be assigned to the different energy dependence of the proton-proton and proton-neutron final state interactions. The experiment has been conducted using a proton beam of the cooler synchrotron COSY and a cluster jet deuteron target. The proton-neutron reactions were tagged by the spectator proton whose momentum was measured for each event. Protons and neutron outgoing from the pn --> pn eta reaction have been registered by means of the COSY-11 facility, an apparatus dedicated for threshold meson production.

1 data table

Total cross section measurement for P N --> P N ETA.


Observation of a near-threshold enhancement in the $e^+e^- \to \Lambda_c^+ \Lambda_c^-$ cross section using initial-state radiation

The Belle collaboration Pakhlova, G. ; Adachi, I. ; Aihara, H. ; et al.
Phys.Rev.Lett. 101 (2008) 172001, 2008.
Inspire Record 791660 DOI 10.17182/hepdata.21861

We report a measurement of the exclusive \$e^+e^- \to \Lambda_c^+ \Lambda_c^-$ cross section as a function of center-of-mass energy near the $\Lambda_c^+ \Lambda_c^-$ threshold. A clear peak with a significance of $8.8\sigma$ is observed in the $\Lambda_c^+ \Lambda_c^-$ invariant mass distribution just above threshold. With an assumption of a resonance origin for the observed peak, a mass and width of $M=(4634^{+8}_{-7} \mathrm{(stat.)} ^{+5}_{-8} \mathrm{(sys.)})\mevc$ and $\Gamma_{\mathrm{tot}}=(92^{+40}_{-24} \mathrm{(stat.)}^{+10}_{-21} \mathrm{(sys.)})\mev$ are determined. The analysis is based on a study of events with initial-state-radiation photons in a data sample collected with the Belle detector at the $\Upsilon(4S)$ resonance and nearby continuum with an integrated luminosity of 695 $\mathrm{fb}^{-1}$ at the KEKB asymmetric-energy $e^+e^_$ collider.

1 data table

Cross section for the exclusive process E+ E- --> LAMBDA/C+ LAMBDA/CBAR-.


Study of Charm Fragmentation into $D^{*\pm}$ Mesons in Deep-Inelastic Scattering at HERA

The H1 collaboration Aaron, F.D. ; Alexa, C. ; Andreev, V. ; et al.
Eur.Phys.J.C 59 (2009) 589-606, 2009.
Inspire Record 792603 DOI 10.17182/hepdata.45316

The process of charm quark fragmentation is studied using $D^{*\pm}$ meson production in deep-inelastic scattering as measured by the H1 detector at HERA. Two different regions of phase space are investigated defined by the presence or absence of a jet containing the $D^{*\pm}$ meson in the event. The parameters of fragmentation functions are extracted for QCD models based on leading order matrix elements and DGLAP or CCFM evolution of partons together with string fragmentation and particle decays. Additionally, they are determined for a next-to-leading order QCD calculation in the fixed flavour number scheme using the independent fragmentation of charm quarks to $D^{*\pm}$ mesons.

20 data tables

Normalised D*+- cross section as a function of zJet for the D*+- jet sample.

Normalised D*+- cross section as a function of zHem for the D*+- jet sample.

Normalised D*+- cross section, corrected to the parton level, as a function of zJet for the D*+- jet sample.

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Angular correlations in three-jet events in ep collisions at HERA

The ZEUS collaboration Chekanov, S. ; Derrick, M. ; Magill, S. ; et al.
Phys.Rev.D 85 (2012) 052008, 2012.
Inspire Record 793931 DOI 10.17182/hepdata.45283

Three-jet production in deep inelastic ep scattering and photoproduction was investigated with the ZEUS detector at HERA using an integrated luminosity of 127 pb-1. Measurements of differential cross sections are presented as functions of angular correlations between the three jets in the final state and the proton-beam direction. These correlations provide a stringent test of perturbative QCD and show sensitivity to the contributions from different colour configurations. Fixed-order perturbative QCD calculations assuming the values of the colour factors C_F, C_A and T_F as derived from a variety of gauge groups were compared to the measurements to study the underlying gauge group symmetry. The measured angular correlations in the deep inelastic ep scattering and photoproduction regimes are consistent with the admixture of colour configurations as predicted by SU(3) and disfavour other symmetry groups, such as SU(N) in the limit of large N.

9 data tables

Integrated 3-jet photoproduction cross section.

Integrated 3-jet cross sections in NC DIS.

Normalized differential 3-jet photoproduction cross section as a function of THETA(H).

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