The differential cross section for n-p elastic scattering at 459 MeV in the c.m. angular region 50°<θ*<180° has been measured with high statistical precision and good relative accuracy. The uncertainty in the absolute normalization (based on the simultaneously measured yield of deuterons from the np→dπ0 reaction) was initially estimated to be ∼7%. The results agree well with back-angle data obtained independently at LAMPF but less well with results from Saclay and the Princeton-Pennsylvania Accelerator and, except for a normalization difference of 10%, are fairly well represented by a phase-shift fit. The pole-extrapolation method of Chew was used to extract the pion-nucleon coupling constant f2 from the back-angle portion of the data. The value obtained, f2=0.069, is somewhat smaller than the values 0.0735–0.0790 obtained from analyses of pion-nucleon scattering, tending to confirm the need for an upward renormalization of the angular distribution by ∼10%.
No description provided.
The reaction d+d→ α + π 0 which is in clear violation of charge symmetry conservation, has been observed for the first time at a laboratory energy of 1.10 GeV in an experiment carried out at the Saturne synchroton at Saclay. The number of π 0 's detected corresponds to a differential cross section d σ d Ω ∗ (π 0 ) = 0.97 ± 0.20 ± 0.15 pb/sr at a centre-of-mass angle of θ c . m . = 107°, where the first error bar refers to the statistical uncertainty and the second to the systematic. The reaction d+d→ α + γ was measured simultaneously with the π 0 production, leading to a differential cross section of d σ d Ω ∗ (γ) = 0.82±0.18±0.10 pb/sr at the slightly larger angle of θ c . m . = 110°. The available predictions of theoretical models of charge symmetry breaking, based upon η / π mixing, fall an order of magnitude below our measurement. However, these predictions for the η / π mixing level might be boosted by the η threshold (1.121 GeV) proximity, where this experiment is performed.
No description provided.
No description provided.
The PS185 experiment at the CERN Low Energy Antiproton Ring (LEAR) has studied the reaction p ̄ p → \ ̄ gLΛ at several momenta. In this paper results from two runs with high statistics at 1.546 GeV/ c and 1.695 GeV/ c are described. Based on 4063 and 11362 analysed events, respectively, differential and integrated cross sections, polarizations and spin correlations are presented. The singlet fraction, extracted from the spin correlations, is consistent with zero at both momenta, showing that the \ ̄ gLΛ pairs are produced in a pure triplet state. A comparison of the decay asymmetry parameters of Λ and \ ̄ gL reduces the upper limits for the violation of the CP invariance for this system.
No description provided.
THE BESTFIT WITH LMAX=3, HI2=1.204.
THE BESTFIT WITH LMAX=6, HI2=0.547.
The production of neutral pions by the interaction of 200A·GeV p and16O projectiles with a Au target has been studied in the pseudorapidity range 1.5≦η≦2.1. Transverse momentum spectra have been measured between 0.4 GeV/c and 3.6 GeV/c and their dependence on the centrality of the collision has been investigated. The peripheral-collision spectra display a marked change of slope with a hard component starting at about 1.8 GeV/c, in contrast to central-collision data. The data are discussed in comparison to p+p and α+α data from the ISR.
Data obtained with minimum bias trigger conditions.
Data obtained with minimum bias trigger conditions.
Data for central collisions.
Transverse momentum ( p T ) distributions of inclusive photons and neutral pions at midrapidity are measured with a lead glass calorimeter in 60 and 200 A GeV 16 O + nucleus and proton + nucleus reactions . The variation of the average transverse momentum is investigated as function of centrality, determined by measurements of the remaining energy of the projectile and the charged particle multiplicity. For small values of the entropy, deduced from the multiplicity density, an increase in average p T is observed levelling off for larger values of entropy. The target-mass and energy dependence of π 0 p T distributions are presented.
No description provided.
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Results are presented from reactions of 60 A GeV and 200 A GeV 16 O projectiles with C, Cu, Ag, and Au nuclei. Energy spectra measured at zero degrees and transverse energy distributions in the pseudorapidity range from 2.4 to 5.5 are shown. The average transverse energy per participant is found to be nearly independent of target mass. Estimates of nuclear stopping and of attained energy densities are made.
STOPPING POWER IS THE QUANTITY GIVEN IN THIS TABLE. IT IS DEFINED AS ( D(ET(EXP)/D(ETA) / D(ET(THEORY)/D(ETA) ) AND THE DENOMINATOR IS TAKEN TO BE 0.5*E(HADRON IN CM). ETA IS THE PSEUDO-RAPIDITY.
500 MeV p→+p elastic and quasielastic, and p→+n quasielastic, analyzing powers (Ay) and spin-rotation-depolarization parameters (DSS, DSL, DLS, DLL, DNN) were determined for center-of-momentum angular ranges 6.8°–55.4° (elastic) and 22.4°–55.4° (quasielastic); liquid hydrogen and deuterium targets were used. The p→+p elastic and quasielastic results are in good agreement; both the p→+p and p→+n parameters are well described by current phase shift solutions.
The elastic P P analysing power at 500 MeV incident proton energy. There is an additional overall normalization uncertainty of 1 PCT.
The spin depolarization and spin rotation parameters in 500 MeV P P elastic interactions. Additional normalization uncertainty of 1 PCT (2 PCT for DLL and DLS).
The elastic P P analysing power at 500 MeV incident proton energy. There is an additional overall normalization uncertainty of 1 PCT.
The processγγπ+π− has been measured with complete particle identification. Cross-sections are presented from near threshold up to the region of thef(1270). In the mass range 0.5–0.7 GeV, crosssections are lower than the Born term predictions and show no evidence for an ε(600). The two-photon width of thef(1270) is found to be in agreement with previous results.
Data for W > 1 GeV read from graph.. Additional overall systematic error 10% for W < 1 GeV, rising to 20% for the 4 lowest W points.
The depolarization parameter D NN for pp elastic scattering at θ cm = 90 ° has been measured at twelve momenta between 0.9 and 1.5 GeV/ c . The moduli of the three transversity amplitudes T 1 , T 3 , and T 4 have been extracted from these data and from previous measurements of the differential cross section and spin correlation parameter A NN (90 °). Smooth energy dependence is found for all three amplitude moduli.
Axis error includes +- 3/3 contribution (DUE TO UNCERTAINTIES IN THE TARGET ANALYSING POWER).
None
No description provided.
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