HEPData Search

Showing 10 of 16 results

Measurement of the Y1S, Y2S and Y3S polarizations in pp collisions at sqrt(s) = 7 TeV

The CMS collaboration Chatrchyan, Serguei ; Khachatryan, Vardan ; Sirunyan, Albert M ; et al.

Phys.Rev.Lett. 110 (2013) 081802, 2013.

Inspire Record 1185414 DOI 10.17182/hepdata.60126

The polarizations of the Y(1S), Y(2S), and Y(3S) mesons are measured in proton-proton collisions at sqrt(s) = 7 TeV, using a data sample of Y(nS) to oppositely charged muon pair decays collected by the CMS experiment, corresponding to an integrated luminosity of 4.9 inverse femtobarns. The dimuon decay angular distributions are analyzed in three different polarization frames. The polarization parameters lambda[theta], lambda[phi], and lambda[theta,phi], as well as the frame-invariant quantity lambda-tilde, are presented as a function of the Y(nS) transverse momentum between 10 and 50 GeV, in the rapidity ranges abs(y) < 0.6 and 0.6 < abs(y) < 1.2. No evidence of large transverse or longitudinal polarizations has been seen in the explored kinematic region.

75 data tables

Table 1

Distribution of Lambda-Theta in the CS frame for Y(1S) production in the |y| range 0.0-0.6.

Table 2

Distribution of Lambda-Theta in the CS frame for Y(1S) production in the |y| range 0.6-1.2.

Table 3

Distribution of Lambda-Phi in the CS frame for Y(1S) production in the |y| range 0.0-0.6.

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Search for Quark Contact Interactions in Dijet Angular Distributions in pp Collisions at sqrt(s) = 7 TeV Measured with the ATLAS Detector

The ATLAS collaboration Aad, G. ; Abbott, B. ; Abdallah, J. ; et al.

Phys.Lett.B 694 (2011) 327-345, 2011.

Inspire Record 871487 DOI 10.17182/hepdata.57022

Dijet angular distributions from the first LHC pp collisions at center-of-mass energy sqrt(s) = 7 TeV have been measured with the ATLAS detector. The dataset used for this analysis represents an integrated luminosity of 3.1 pb-1. Dijet $\chi$ distributions and centrality ratios have been measured up to dijet masses of 2.8 TeV, and found to be in good agreement with Standard Model predictions. Analysis of the $\chi$ distributions excludes quark contact interactions with a compositeness scale $\Lambda$ below 3.4 TeV, at 95% confidence level, significantly exceeding previous limits.

5 data tables

Table 1

CHI distribution for mass bin 340 to 520 GeV.

Table 2

CHI distribution for mass bin 520 to 800 GeV.

Table 3

CHI distribution for mass bin 800 to 1200 GeV.

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Search for New Particles in Two-Jet Final States in 7 TeV Proton-Proton Collisions with the ATLAS Detector at the LHC

The ATLAS collaboration Aad, G. ; Abbott, B. ; Abdallah, J. ; et al.

Phys.Rev.Lett. 105 (2010) 161801, 2010.

Inspire Record 865423 DOI 10.17182/hepdata.57036

A search for new heavy particles manifested as resonances in two-jet final states is presented. The data were produced in 7 TeV proton-proton collisions by the Large Hadron Collider (LHC) and correspond to an integrated luminosity of 315 nb^-1 collected by the ATLAS detector. No resonances were observed. Upper limits were set on the product of cross section and signal acceptance for excited-quark (q*) production as a function of q* mass. These exclude at the 95% CL the q* mass interval 0.30 < mq* < 1.26 TeV, extending the reach of previous experiments.

2 data tables

Table 1

The dijet mass distribution (NUMBER OF EVENTS).

Table 2

95 PCT CL upper limit of the cross section x acceptance.

Cross-Sections of Large-Angle Hadron Production in Proton- and Pion-Nucleus Interactions I: Beryllium Nuclei and Beam Momenta of +8.9 Gev/c and -8.0 Gev/c

The HARP-CDP Group collaboration Bolshakova, A. ; Boyko, I. ; Chelkov, G. ; et al.

Eur.Phys.J.C 62 (2009) 293-317, 2009.

Inspire Record 811688 DOI 10.17182/hepdata.51594

We report on double-differential inclusive cross-sections of the production of secondary protons, deuterons, and charged pions and kaons, in the interactions with a 5% nuclear interaction length thick stationary beryllium target, of a +8.9 GeV/c proton and pion beam, and a -8.0 GeV/c pion beam. Results are given for secondary particles with production angles between 20 and 125 degrees.

76 data tables

Table 1

Double differential inclusive cross section for the reaction P BE --> P X with an 8.9 GeV beam and production angle 20 to 30 degrees.

Table 2

Double differential inclusive cross section for the reaction P BE --> P X with an 8.9 GeV beam and production angle 30 to 40 degrees.

Table 3

Double differential inclusive cross section for the reaction P BE --> P X with an 8.9 GeV beam and production angle 40 to 50 degrees.

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rivet Analysis
Charged particle multiplicity distributions in Z0 hadronic decays

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adami, F. ; et al.

Z.Phys.C 50 (1991) 185-194, 1991.

Inspire Record 301657 DOI 10.17182/hepdata.15028

This paper presents an analysis of the multiplicity distributions of charged particles produced inZ0 hadronic decays in the DELPHI detector. It is based on a sample of 25364 events. The average multiplicity is <nch>=20.71±0.04(stat)±0.77(syst) and the dispersionD=6.28±0.03(stat)±0.43(syst). The data are compared with the results at lower energies and with the predictions of phenomenological models. The Lund parton shower model describes the data reasonably well. The multiplicity distributions show approximate KNO-scaling. They also show positive forward-backward correlations that are strongest in the central region of rapidity and for particles of opposite charge.

5 data tables

Table 1

Charged particle multiplicity distribution for the raw data in full phase space.

Table 2

Charged particle multiplicity distribution for full phase space. Errors include systematics. A 2 pct correction for excess electrons from photon conversions is not included. The first two points, at N=2 and 4, were not measured but taken from the Lund PS model.

Table 3

Charged particle multiplicity distribution for single hemisphere. Errors include systematics. A 2 pct correction for excess electrons from photon conversions is not included.