Evidence for Collective Multiparticle Correlations in p-Pb Collisions

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M ; Tumasyan, Armen ; et al.
Phys.Rev.Lett. 115 (2015) 012301, 2015.
Inspire Record 1345262 DOI 10.17182/hepdata.67530

The second-order azimuthal anisotropy Fourier harmonics, v2, are obtained in pPb and PbPb collisions over a wide pseudorapidity (eta) range based on correlations among six or more charged particles. The pPb data, corresponding to an integrated luminosity of 35 inverse nanobarns, were collected during the 2013 LHC pPb run at a nucleon-nucleon center-of-mass energy of 5.02 TeV by the CMS experiment. A sample of semi-peripheral PbPb collision data at sqrt(s[NN])= 2.76 TeV, corresponding to an integrated luminosity of 2.5 inverse microbarns and covering a similar range of particle multiplicities as the pPb data, is also analyzed for comparison. The six- and eight-particle cumulant and the Lee-Yang zeros methods are used to extract the v2 coefficients, extending previous studies of two- and four-particle correlations. For both the pPb and PbPb systems, the v2 values obtained with correlations among more than four particles are consistent with previously published four-particle results. These data support the interpretation of a collective origin for the previously observed long-range (large Delta[eta]) correlations in both systems. The ratios of v2 values corresponding to correlations including different numbers of particles are compared to theoretical predictions that assume a hydrodynamic behavior of a pPb system dominated by fluctuations in the positions of participant nucleons. These results provide new insights into the multi-particle dynamics of collision systems with a very small overlapping region.

0 data tables match query

Production of $\Upsilon(1S)$ mesons from $\chi_b$ decays in $p\bar{p}$ collisions at $\sqrt{s} = 1.8$ TeV

The CDF collaboration Affolder, T. ; Akimoto, H. ; Akopian, A. ; et al.
Phys.Rev.Lett. 84 (2000) 2094-2099, 2000.
Inspire Record 508395 DOI 10.17182/hepdata.50106

We have reconstructed the radiative decays $\chi_{b}(1P) \to \Upsilon(1S) \gamma $ and $\chi_{b}(2P) \to \Upsilon(1S) \gamma $ in $p \bar{p}$ collisions at $\sqrt{s} = 1.8$ TeV, and measured the fraction of $\Upsilon(1S)$ mesons that originate from these decays. For $\Upsilon(1S)$ mesons with $p^{\Upsilon}_{T}>8.0$ GeV/$c$, the fractions that come from $\chi_{b}(1P)$ and $\chi_{b}(2P)$ decays are $(27.1\pm6.9(stat)\pm4.4(sys))%$ and $(10.5\pm4.4(stat)\pm1.4(sys))%$, respectively. We have derived the fraction of directly produced $\Upsilon(1S)$ mesons to be $(50.9\pm8.2(stat)\pm9.0(sys))%$.

0 data tables match query

Forward-backward charge asymmetry of electron pairs above the $Z^0$ pole

The CDF collaboration Abe, F. ; Akimoto, H. ; Akopian, A. ; et al.
Phys.Rev.Lett. 77 (1996) 2616-2621, 1996.
Inspire Record 417098 DOI 10.17182/hepdata.50121

We present a measurement of the forward-backward charge asymmetry of the process pp¯→Z0/γ+X,Z0/γ→e+e− at Mee>MZ, using 110pb−1 of data at s=1.8TeV collected at the Collider Detector at Fermilab. The measured charge asymmetries are 0.43±0.10 in the invariant mass region Mee>105GeV/c2, and 0.070±0.016 in the region 75<Mee<105GeV/c2. These results are consistent with the standard model values of 0.528±0.009 and 0.052±0.002, respectively.

0 data tables match query

Measurements of polarization in pi- p elastic scattering at large angles

Hill, D. ; Koehler, P.F.M. ; Novey, T.B. ; et al.
Phys.Rev.Lett. 27 (1971) 1241-1243, 1971.
Inspire Record 68894 DOI 10.17182/hepdata.229

We have made measurements of polarization in π−p elastic scattering, with emphasis over the backward region, at 1.60 to 2.28 GeVc. The results indicate the absence of u-channel dominance in the backward region, as was observed in the case of π+p scattering. Comparisons have been made with predictions of various phase-shift analyses which show that the agreement is generally very poor in the backward region.

0 data tables match query

Large angle differential cross-section for k+ p elastic scattering at 4.0 and 5.0 gev/c

Akerlof, C.W. ; Han, K.S. ; Meyer, D.I. ; et al.
Phys.Rev.Lett. 26 (1971) 1278-1279, 1971.
Inspire Record 68998 DOI 10.17182/hepdata.21514

We present data on the reaction K+p→K+p at large angles. Between the forward diffraction peak and the backward peak the cross section is independent of four-momentum transfer but varies with incident momentum.

0 data tables match query

Mass identified particle production in $p\bar{p}$ collisions at $\sqrt{s}$ = 300-GeV, 540-GeV, 1000-GeV, and 1800-GeV

The E735 collaboration Alexopoulos, T. ; Allen, C. ; Anderson, E.W. ; et al.
Phys.Rev.D 48 (1993) 984-997, 1993.
Inspire Record 363171 DOI 10.17182/hepdata.22669

The yields and average transverse momenta of pions, kaons, and antiprotons produced at the Fermilab p¯p collider at s=300, 540, 1000, and 1800 GeV are presented and compared with data from the energies reached at the CERN collider. We also present data on the dependence of average transverse momentum 〈pt〉 and particle ratios as a function of charged particle density dNcdη; data for particle densities as high as six times the average value, corresponding to a Bjorken energy density 6 GeV/fm3, are reported. These data are relevant to the search for quark-gluon phase of QCD.

0 data tables match query

Test of Scaling of the Massive Dihadron Cross-section

Kaplan, D.M. ; Guo, R. ; Brown, C.N. ; et al.
Phys.Rev.D 41 (1990) 2334, 1990.
Inspire Record 285484 DOI 10.17182/hepdata.22990

Measurements of the cross section for production of massive dihadrons by 800-GeV protons incident on a tungsten target are presented. These are compared with measurements taken at lower and higher s and with perturbative-QCD predictions. Scaling and A-dependence behaviors observed at lower energies are confirmed, and good agreement with QCD is obtained. Model dependences of earlier measurements are discussed.

0 data tables match query

Measurement of the polarization parameter in backward pi+ p elastic scattering at 1.60, 1.80, 2.11, and 2.31 gev/c

Burleson, G. ; Hill, D. ; Kato, S. ; et al.
Phys.Rev.Lett. 26 (1971) 338-340, 1971.
Inspire Record 69051 DOI 10.17182/hepdata.21558

Measurements of polarization in π+p elastic scattering have been made at 1.60, 1.80, 2.11, and 2.31 GeVc. The data cover the entire angular range, with emphasis on the backward region. Comparisons have been made with both u-channel and t-channel models, as well as with predictions of phase-shift analyses. While the agreement is generally poor in all cases, the best agreement is with some t-channel predictions.

0 data tables match query

COMPTON SCATTERING FROM HYDROGEN BETWEEN 5-GeV AND 17-GeV

Anderson, Robert L. ; Gustavson, D. ; Johnson, J.R. ; et al.
Phys.Rev.Lett. 25 (1970) 1218, 1970.
Inspire Record 60845 DOI 10.17182/hepdata.21597

Measurements have been made on Compton scattering for photon energies between 5 and 17 GeV and t values from -0.06 to -1.1 (GeVc)2. The data were obtained by performing a coincidence between the Stanford Linear Accelerator Center 1.6-GeVc spectrometer and a Lucite shower counter. The scattering appears diffractive out to high t values, but the cross sections seem not to be in good agreement with the prediction of a strict vector-meson-dominance model.

0 data tables match query

Two-body neutral final states produced in $\bar{p}p$ annihilations at 2.911-GeV <= $\sqrt{s}$ <= 3.686-GeV

The Fermilab E760 collaboration Armstrong, T.A. ; Bettoni, D. ; Bharadwaj, V. ; et al.
Phys.Rev.D 56 (1997) 2509-2531, 1997.
Inspire Record 444897 DOI 10.17182/hepdata.22300

We have performed an experiment in the Antiproton Accumulator at Fermilab to study two-body neutral final states formed in p¯p annihilations. Differential cross sections are determined in the center-of-mass energy range 2.911<s<3.686 GeV for the final states π0π0, ηπ0, ηη, π0γ, and γγ. The energy dependence of differential cross sections at 90° in the center of mass is studied to test the predictions of phenomenological QCD scaling hypotheses which predict power-law dependence.

0 data tables match query