HEPData Search

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Charged particle multiplicities in nuclear collisions at 200-GeV/N

The NA35 collaboration Bächler, J. ; Bartke, J. ; Bialkowska, H. ; et al.

Z.Phys.C 51 (1991) 157-162, 1991.

Inspire Record 320907 DOI 10.17182/hepdata.14983

Data on multiplicities of charged particles produced in proton-nucleus and nucleus-nucleus collisions at 200 GeV per nucleon are presented. It is shown that the mean multiplicity of negative particles is proportional to the mean number of nucleons participating in the collision both for nucleus-nucleus and proton-nucleus collisions. The apparent consistency of pion multiplicity data with the assumption of an incoherent superposition of nucleon-nucleon collisions is critically discussed.

4 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Forward peak in $\pi^+$ photoproduction

Buschhorn, G. ; Heide, P. ; Kötz, U. ; et al.

Phys.Lett.B 25 (1967) 622-623, 1967.

Inspire Record 1392927 DOI 10.17182/hepdata.29549

The π+—photoproduction cross section is found to have a peak in the forward direction in disagreement with simple Regge pole models.

1 data table

Table 1

No description provided.

Two-pion Bose-Einstein correlations in central PbPb collisions at sqrt(s_NN) = 2.76 TeV

The ALICE collaboration Aamodt, K. ; Abrahantes Quintana, A. ; Adamova, D. ; et al.

Phys.Lett.B 696 (2011) 328-337, 2011.

Inspire Record 881884 DOI 10.17182/hepdata.56743

The first measurement of two-pion Bose-Einstein correlations in central Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ TeV at the Large Hadron Collider is presented. We observe a growing trend with energy now not only for the longitudinal and the outward but also for the sideward pion source radius. The pion homogeneity volume and the decoupling time are significantly larger than those measured at RHIC.

14 data tables

Table 1

Projections of the correlation function C.

Table 2

Projections of the correlation function C.

Table 3

Projections of the correlation function C.

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Pion and kaon production in central Pb+Pb collisions at 20A and 30A GeV: Evidence for the onset of deconfinement

The NA49 collaboration Alt, C. ; Anticic, T. ; Baatar, B. ; et al.

Phys.Rev.C 77 (2008) 024903, 2008.

Inspire Record 762554 DOI 10.17182/hepdata.25169

Results on charged pion and kaon production in central Pb+Pb collisions at 20A and 30A GeV are presented and compared to data at lower and higher energies. A rapid change of the energy dependence is observed around 30A GeV for the yields of pions and kaons as well as for the shape of the transverse mass spectra. The change is compatible with the prediction that the threshold for production of a state of deconfined matter at the early stage of the collisions is located at low SPS energies.

13 data tables

Table 1

Transverse mass spectra for pion production in the central rapidity region for collisions at 20 GeV per nucleon.

Table 2

Transverse mass spectra for pion production in the central rapidity region for collisions at 30 GeV per nucleon.

Table 3

Transverse mass spectra for kaon production in the central rapidity region for collisions at 20 GeV per nucleon.

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Compton scattering cross section on the proton at high momentum transfer.

The Hall A collaboration Danagoulian, A. ; Mamyan, V.H. ; Roedelbronn, M. ; et al.

Phys.Rev.Lett. 98 (2007) 152001, 2007.

Inspire Record 743383 DOI 10.17182/hepdata.31472

Cross-section values for Compton scattering on the proton were measured at 25 kinematic settings over the range s = 5-11 and -t = 2-7 GeV2 with statistical accuracy of a few percent. The scaling power for the s-dependence of the cross section at fixed center of mass angle was found to be 8.0 +/ 0.2, strongly inconsistent with the prediction of perturbative QCD. The observed cross-section values are in fair agreement with the calculations using the handbag mechanism, in which the external photons couple to a single quark.

4 data tables

Table 1

Cross section of proton Compton Scattering at centre of mass energy squared of 4.82 GeV.

Table 2

Cross section of proton Compton Scattering at centre of mass energy squared of 6.79 GeV.

Table 3

Cross section of proton Compton Scattering at centre of mass energy squared of 8.90 GeV.

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Cross section measurement of charged pion photoproduction from hydrogen and deuterium.

The Jefferson Lab Hall A collaboration Zhu, L.Y. ; Arrington, J. ; Averett, T. ; et al.

Phys.Rev.Lett. 91 (2003) 022003, 2003.

Inspire Record 601768 DOI 10.17182/hepdata.31722

We have measured the differential cross section for the gamma n --> pi- p and gamma p --> pi+ n reactions at center of mass angle of 90 degree in the photon energy range from 1.1 to 5.5 GeV at Jefferson Lab (JLab). The data at photon energies greater than 3.3 GeV exhibit a global scaling behavior for both pi- and pi+ photoproduction, consistent with the constituent counting rule and the existing pi+ photoproduction data. Possible oscillations around the scaling value are suggested by these new data The data show enhancement in the scaled cross section at a center-of-mass energy near 2.2 GeV. The cross section ratio of exclusive pi- to pi+ photoproduction at high energy is consistent with the prediction based on one-hard-gluon-exchange diagrams.

1 data table

Table 1

Differential cross section at THETA(CM) = 90 degrees.

A Precise Determination of the Electroweak Mixing Angle from Semileptonic Neutrino Scattering

The CHARM collaboration Allaby, J.V. ; Amaldi, U. ; Barbiellini, G. ; et al.

Z.Phys.C 36 (1987) 611, 1987.

Inspire Record 249672 DOI 10.17182/hepdata.15697

The cross-section ratio of neutral-current and charged-current semileptonic interactions of muon-neutrinos on isoscalar nuclei has been measured with the result:Rv=0.3093±0.0031 for hadronic energy larger than 4 GeV. From this ratio we determined the electroweak mixing angle sin2θW, wheremc is the charm-quark mass in GeV/c2. Comparison with direct measurements ofmw andmz determines the radiative shift of the intermediate boson mass Δr=0.077±0.025(exp.)±0.038(syst.), in agreement with the prediction. Assuming the validity of the electroweak standard theory we determined ϱ=0.990−0.013(mc−1.5)±0.009(exp.)±0.003(theor.).

3 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

STATISTICAL ERROR IN THE VALUE CITED IS REDUCING, WHEN CUT IS MORE STRINGENT?.

MEASUREMENTS OF SHADOWING IN LOW Q**2 ELECTROPRODUCTION ON NUCLEI

Bailey, J. ; Botterill, D.R. ; Montgomery, Hugh E. ; et al.

Nucl.Phys.B 151 (1979) 367-388, 1979.

Inspire Record 132234 DOI 10.17182/hepdata.34763

Measurements of inelastic electron scattering have been made in the range 2.2 < ν < 3.8 GeV and 0.1 < | Q 2 | < 0.3 (GeV/ c ) 2 , on a selection of nuclei ranging from hydrogen and deuterium to uranium, by measuring the scattered electron only. Detailed calculations have been made of the contribution of radiative tails to the measured yield. The results show a small ‘shadowing’ consistent with other electroproduction experiments, and also with photoproduction experiments in this ν range, but the shadowing decreases rapidly as | Q 2 | increases.

4 data tables

Table 1

DEUTERIUM TO HYDROGEN CROSS SECTION RATIO (PER NUCLEON). FOR E(P=3) = 2.25 AND THETA = 8.5, THE RATIO IS 0.911 +- 0.037 (DSYS = 0.040).

Table 2

No description provided.

Table 3

No description provided.

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Small Angle Compton Scattering on Hydrogen and Deuterium

Criegee, L. ; Franke, G. ; Giese, A. ; et al.

Nucl.Phys.B 121 (1977) 31-37, 1977.

Inspire Record 118810 DOI 10.17182/hepdata.35467

We have measured elastic scattering of 5 and 6 GeV photons on hydrogen and deuterium in the angular range 10–50 mrad. On hydrogen we observe a forward diffraction peak with a slope of 8.5 (GeV/ c ) −2 . The extrapolated forward cross sections in units μ b/(GeV/ c ) 2 are 0.82 ± 0.04 at 5 GeV and 0.79 ± 0.04 at 6 GeV. They are consistent with the calculated amplitudes obtained from total cross section measurements via the optical theorem and dispersion relations assuming negligible contributions of spin-dependent amplitudes. Deuterium cross sections show a transition from coherent scattering at low | t | to incoherent scattering at higher | t |. They indicate that the isovector exchange amplitude a 1 is very small compared to the isoscalar a 0 . We obtain |a 1 | 2 /|a 0 +a 1 | 2 =0.13±0.09 , Re (a 0 a ∗ 1 )/|a 0 +a 1 | 2 =0.0±0.03, at 5 GeV , |a 1 | 2 /|a 0 +a 1 | 2 =−0.12±0.15 , Re (a 0 a ∗ 1 )/|a 0 +a 1 | 2 =0.10±0.04, at 6 GeV .

2 data tables

Table 1

No description provided.

Table 2

No description provided.