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

Abstract

We report on double-differential inclusive crosssections of the production of secondary protons, deuterons, and charged pions and kaons, in the interactions with a 5% λ abs 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 20 • < θ < 125 • .

Cross-sections of large-angle hadron production in proton– and pion–nucleus interactions IV: copper nuclei and beam momenta from ±3 GeV/c to ±15 GeV/c

“…We select 'good' accelerator spills by requiring a minimal beam intensity and a 'smooth' variation of beam intensity across the 400 ms long spill. 1 The target was a disc made of high-purity (99.99%) copper, with a density of 8.91 g/cm 3 , a radius of 15.1 mm, and a thickness of 7.52 ± 0.05 mm (5% λ abs ).…”

“…Therefore, TPC track distortions do not affect the precision of our cross-section measurements. 1 A smooth variation of beam intensity eases corrections for dynamic TPC track distortions. 2 A right-handed Cartesian and/or spherical polar coordinate system is employed; the z axis coincides with the beam line, with +z pointing downstream; the coordinate origin is at the upstream end of the copper target, 500 mm downstream of the TPC's pad plane; looking downstream, the +x coordinate points to the left and the +y coordinate points up; the polar angle θ is the angle with respect to the +z axis.…”

“…4 The systematic error of the track finding efficiency is taken as 1% which reflects differences between results from different persons who conducted eyeball scans. We also take the statistical errors of the parameters of a fit to scan results as systematic error into account [1]. The systematic error of the correction for losses from the requirement of at least 10 TPC clusters per track is taken as 20% of the correction which itself is in the range of 5 to 30%.…”

“…6 We observe no appreciable dependence of the deuteron to proton ratio on beam momentum. 7 The beryllium data with +8.9 GeV/c beam momentum [1,2] have been scaled, by interpolation, to a beam momentum of 8.0 GeV/c. Figure 10 shows their published Lorentz-invariant crosssection of π + and π − production by +14.6 GeV/c protons, in the rapidity range 1.2 < y < 1.4, as a function of m T − m π , where m T denotes the pion transverse mass.…”

“…This is the fourth of a series of cross-section papers with results from the HARP experiment. In the first paper, [1], we described the detector characteristics and our analysis algorithms, on the example of +8.9 GeV/c and −8.0 GeV/c beams impinging on a 5% λ abs Be target. The second paper [2] presented results for all beam momenta from this Be target, and the third paper [3] results from the interactions with a 5% λ abs Ta target.…”