In an exposure of the chamber Mirabelle at the Serpukhov accelerator, 1 943 interactions at 50 GeV/ c and 8 959 at 69 GeV/ c have been observed. Topological cross sections and charged multiplicity distributions are presented. The average charged multiplicities found are respectively 5.32 ± 0.13 and 5.89 ± 0.07.
2PRONG INELASTIC CROSS SECTIONS DERIVED BY SUBTRACTION OF OTHER PRONG CROSS SECTIONS AND KNOWN ELASTIC MEASUREMENTS FROM THE TOTAL.
Results are presented from the first p p colliding beam runs at the CERN ISR, using the UA5 streamer chamber detector. p p interactions at s = 53 GeV are compared with pp data taken in the same experiment. The results are in good agreement with extrapolations of low-energy p p data.
No description provided.
MOMENTS OF MULTIPLICITY DISTRIBUTIONS FOR P P AND P AP. MULT(NAME=DQ) IS <(N-<N>)**Q>**1/Q. MULT(NAME=NQ) IS <N**Q>.
Data read from plot.
We report the beam energy (\sqrt s_{NN} = 7.7 - 200 GeV) and collision centrality dependence of the mean (M), standard deviation (\sigma), skewness (S), and kurtosis (\kappa) of the net-proton multiplicity distributions in Au+Au collisions. The measurements are carried out by the STAR experiment at midrapidity (|y| < 0.5) and within the transverse momentum range 0.4 < pT < 0.8 GeV/c in the first phase of the Beam Energy Scan program at the Relativistic Heavy Ion Collider. These measurements are important for understanding the Quantum Chromodynamic (QCD) phase diagram. The products of the moments, S\sigma and \kappa\sigma^{2}, are sensitive to the correlation length of the hot and dense medium created in the collisions and are related to the ratios of baryon number susceptibilities of corresponding orders. The products of moments are found to have values significantly below the Skellam expectation and close to expectations based on independent proton and anti-proton production. The measurements are compared to a transport model calculation to understand the effect of acceptance and baryon number conservation, and also to a hadron resonance gas model.
$\Delta N_p$ multiplicity distributions in Au+Au collisions at $\sqrt{S_{NN}}=7.7$ GeV for 0-5 percent, 30-40 percent and 70-80 percent collision centralities at midrapidity.
$\Delta N_p$ multiplicity distributions in Au+Au collisions at $\sqrt{S_{NN}}=11.5$ GeV for 0-5 percent, 30-40 percent and 70-80 percent collision centralities at midrapidity.
$\Delta N_p$ multiplicity distributions in Au+Au collisions at $\sqrt{S_{NN}}=19.6$ GeV for 0-5 percent, 30-40 percent and 70-80 percent collision centralities at midrapidity.
The highest-energy measurement of ΔσL(pp) and the first ever measurement of ΔσL(p¯p), the differences between proton-proton and antiproton-proton total cross sections for pure longitudinal spin states, are described. Data were taken using 200-GeV/c polarized beams incident on a polarized-proton target. The results are measured to be ΔσL(pp)=−42±48(stat)±53(syst) μb and ΔσL(p¯p)=−256±124(stat)±109(syst) μb. Many tests of systematic effects were investigated and are described, and a comparison to theoretical predictions is also given. Measurements of parity nonconservation at 200 GeV/c in proton scattering and the first ever of antiproton scattering have also been derived from these data. The values are consistent with zero at the 10−5 level.
No description provided.
No description provided.
Measurements of multiplicity and transverse momentum fluctuations of charged particles were performed in inelastic p+p interactions at 20, 31, 40, 80 and 158 GeV/c beam momentum. Results for the scaled variance of the multiplicity distribution and for three strongly intensive measures of multiplicity and transverse momentum fluctuations \$\Delta[P_{T},N]\$, \$\Sigma[P_{T},N]\$ and \$\Phi_{p_T}\$ are presented. For the first time the results on fluctuations are fully corrected for experimental biases. The results on multiplicity and transverse momentum fluctuations significantly deviate from expectations for the independent particle production. They also depend on charges of selected hadrons. The string-resonance Monte Carlo models EPOS and UrQMD do not describe the data. The scaled variance of multiplicity fluctuations is significantly higher in inelastic p+p interactions than in central Pb+Pb collisions measured by NA49 at the same energy per nucleon. This is in qualitative disagreement with the predictions of the Wounded Nucleon Model. Within the statistical framework the enhanced multiplicity fluctuations in inelastic p+p interactions can be interpreted as due to event-by-event fluctuations of the fireball energy and/or volume.
Energy dependence of $\Delta[P_{T},N]$ for three charge selections
Energy dependence of $\Delta[P_{T},N]$ for three charge selections
Energy dependence of $\Sigma[P_{T},N]$ for three chrge selections
We have measured the differential cross section for small angle p−p scattering from 25 to 200 GeV incident energy and in the momentum transfer range 0.015<|t|<0.080 (GeVc)2. We find that the slope of the forward diffraction peak, b(s), increases with energy and can be fitted by the form b(s)=b0+2α′ lns, where b0=8.3±1.3 and α′=0.28±0.13 (GeVc)−2. Such dependence is compatible with the data existing both at higher and lower energies. We have also obtained the energy dependence of the p−p total cross section in the energy range from 48 to 196 GeV. Within our errors which are ± 1.1 mb the total cross section remains constant.
No description provided.
THE TOTAL CROSS SECTION IS NORMALIZED TO 38.5 +- 0.1 MB AT 48 GEV. IT HAS BEEN DERIVED USING THE OPTICAL THEOREM FROM THE EXTRAPOLATED FORWARD ELASTIC CROSS SECTION AND WITH ALPHA = -0.09.
The energy dependence of the average of the charged multiplicity and its dispersion in π + /K + /p interaction on protons at 147 GeV/ c is found to be the same as in e + e − annihilations if an “effective energy” variable is used instead of the total energy. The effective energy S eff is defined as the invariant mass of all secondaries left after the two leading particles have been removed. Fitting the expression aS eff b to the average charge multiplicity 〈 n ch 〉, we find the power b to be in good agreement with the value of 0.25 predicted by Fermi's statistical model and by Landau's hydrodynamical model.
BINS IN WEFF SELECTED SO AS TO YIELD 200 EVENTS IN EACH BIN.
200 EVENTS IN EACH BIN IN WEFF.
50 EVENTS IN EACH BIN IN WEFF.
The Fermilab hybrid 30-in. bubble-chamber spectrometer was exposed to a tagged 147-GeV/c positive beam containing π+, K+, and p. A sample of 3003 K+p, 19410 pp, and 20745 π+p interactions is used to derive σn, 〈n〉, f2cc, and 〈nc〉D for each beam particle. These values are compared to values obtained at other, mostly lower, beam momenta. The overall dependence of 〈n〉 on Ea, the available center-of-mass energy, for these three reactions as well as π−p and pp interactions has been determined.
No description provided.
No description provided.
No description provided.
Measurements of the midrapidity transverse energy distribution, $d\Et/d\eta$, are presented for $p$$+$$p$, $d$$+$Au, and Au$+$Au collisions at $\sqrt{s_{_{NN}}}=200$ GeV and additionally for Au$+$Au collisions at $\sqrt{s_{_{NN}}}=62.4$ and 130 GeV. The $d\Et/d\eta$ distributions are first compared with the number of nucleon participants $N_{\rm part}$, number of binary collisions $N_{\rm coll}$, and number of constituent-quark participants $N_{qp}$ calculated from a Glauber model based on the nuclear geometry. For Au$+$Au, $\mean{d\Et/d\eta}/N_{\rm part}$ increases with $N_{\rm part}$, while $\mean{d\Et/d\eta}/N_{qp}$ is approximately constant for all three energies. This indicates that the two component ansatz, $dE_{T}/d\eta \propto (1-x) N_{\rm part}/2 + x N_{\rm coll}$, which has been used to represent $E_T$ distributions, is simply a proxy for $N_{qp}$, and that the $N_{\rm coll}$ term does not represent a hard-scattering component in $E_T$ distributions. The $dE_{T}/d\eta$ distributions of Au$+$Au and $d$$+$Au are then calculated from the measured $p$$+$$p$ $E_T$ distribution using two models that both reproduce the Au$+$Au data. However, while the number-of-constituent-quark-participant model agrees well with the $d$$+$Au data, the additive-quark model does not.
Et EMC distributions for sqrt(sNN) = 62.4 GeV Au+Au collisions shown in 5% wide centrality bins.
Et EMC distributions for sqrt(sNN) = 62.4 GeV Au+Au collisions shown in 5% wide centrality bins.
Et EMC distributions for sqrt(sNN) = 62.4 GeV Au+Au collisions shown in 5% wide centrality bins.
Results on two-particle $\Delta\eta\Delta\phi$ correlations in inelastic p+p interactions at 20, 31, 40, 80, and 158~GeV/c are presented. The measurements were performed using the large acceptance NA61/SHINE hadron spectrometer at the CERN Super Proton Synchrotron. The data show structures which can be attributed mainly to effects of resonance decays, momentum conservation, and quantum statistics. The results are compared with the EPOS and UrQMD models.
Two-particle correlation function C(Delta eta, Delta phi) for all charge pairs in inelastic p+p interactions at 20 GeV/c.
Two-particle correlation function C(Delta eta, Delta phi) for all charge pairs in inelastic p+p interactions at 31 GeV/c.
Two-particle correlation function C(Delta eta, Delta phi) for all charge pairs in inelastic p+p interactions at 40 GeV/c.
The charged-particle multiplicity distribution in 205−GeVc proton-proton interactions is presented. In addition, the total diffractive contributions to each charged multiplicity are estimated assuming a factorizable Pomeron.
THE TOTAL CROSS SECTION NORMALIZATION COMES FROM THIS AND OTHER EXPERIMENTS.
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