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

We report on double-differential inclusive cross-sections 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^○. On leave of absence at Ecole Polytechnique Fédérale, Lausanne, Switzerland.     

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

We report on double-differential inclusive cross-sections of the production of secondary protons and charged pions, in the interactions with a 5% λ _abs thick stationary beryllium target, of proton and pion beams with momentum from ±3 GeV/c to ±15 GeV/c. 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 V: lead nuclei and beam momenta from ±3 GeV/c to ±15 GeV/c

We report on double-differential inclusive cross-sections of the production of secondary protons, charged pions, and deuterons, in the interactions with a 5% λ _int thick stationary lead target, of proton and pion beams with momentum from ±3 GeV/c to ±15 GeV/c. Results are given for secondary particles with production angles 20°<θ<125°. Cross-sections on lead nuclei are compared with cross-sections on beryllium, copper, and tantalum nuclei.     

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

We report on double-differential inclusive cross-sections of the production of secondary protons, charged pions, and deuterons, in the interactions with a 5% λ _int thick stationary carbon target, of proton and pion beams with momentum from ±3 GeV/c to ±15 GeV/c. Results are given for secondary particles with production angles 20°<θ<125°. Cross-sections on carbon nuclei are compared with cross-sections on beryllium, copper, tantalum and lead nuclei.     

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

We report on double-differential inclusive cross sections of the production of secondary protons, charged pions, and deuterons, in the interactions with a 5% λ _abs thick stationary tantalum target, of proton and pion beams with momentum from ±3 GeV/c to ±15 GeV/c. Results are given for secondary particles with production angles 20°<θ<125°. They are of particular relevance for the optimization of the design parameters of the proton driver of a neutrino factory.     

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 report on double-differential inclusive cross-sections of the production of secondary protons, charged pions, and deuterons, in the interactions with a 5% λ _abs thick stationary copper target, of proton and pion beams with momentum from ±3 GeV/c to ±15 GeV/c. Results are given for secondary particles with production angles 20°<θ<125°. The inclusive pion production cross-sections are compared to those on beryllium and tantalum, published by us recently.     

Study of longitudinal correlations between pions from fragmentation processes inK − p interactions at 32 GeV/c

Longitudinal correlations between pions inclusively produced in the target and beam fragmentation regions are studied in aK ^? p bubble chamber experiment at 32 GeV/c with a sensitivity of about 6.7 ev/μb. It was found that the \({{\tilde x_2 = x_2 } \mathord{\left/ {\vphantom {{\tilde x_2 = x_2 } {(1 - \left| {x_1 } \right|)}}} \right. \kern-0em} {(1 - \left| {x_1 } \right|)}}\) distributions of charged pions with momentum fraction in the proton hemisphere with respect to a charged “trigger” pion with momentum fraction x₁ do not show scaling, that those of the associated π₁/π₂ do not compare toK ⁺ p interactions and give indications for quark annihilation. The invariant two- and three pion longitudinal C.M. distributions show significant deviations from the naive quark recombination picture. Distinct long-range correlations observed between π^? s from the proton fragmentation region and π⁺ s from theK ^? fragmentation region could imply contributions from quark exchange or quark annihilation mechanisms inK ^? p interactions at 32 GeV/c.     

Measurement of the production cross-section of positive pions in p–Al collisions at 12.9 GeV/c

A precision measurement of the double-differential production cross-section, $d^2{\sigma }^{{\pi }^{+}}/dpd\Omega$, for pions of positive charge, performed in the HARP experiment is presented. The incident particles are protons of $12.9\text{ GeV}/c$ momentum impinging on an aluminium target of 5% nuclear interaction length. The measurement of this cross-section has a direct application to the calculation of the neutrino flux of the K2K experiment. After cuts, 210 000 secondary tracks reconstructed in the forward spectrometer were used in this analysis. The results are given for secondaries within a momentum range from 0.75 to 6.5 GeV/c, and within an angular range from 30 mrad to 210 mrad. The absolute normalization was performed using prescaled beam triggers counting protons on target. The overall scale of the cross-section is known to better than 6%, while the average point-to-point error is 8.2%.     

Inclusive production of protons, anti-protons and neutrons in p+p collisions at 158 GeV/c beam momentum

New data on the production of protons, anti-protons and neutrons in p+p interactions are presented. The data come from a sample of 4.8 million inelastic events obtained with the NA49 detector at the CERN SPS at 158 GeV/c beam momentum. The charged baryons are identified by energy loss measurement in a large TPC tracking system. Neutrons are detected in a forward hadronic calorimeter. Inclusive invariant cross sections are obtained in intervals from 0 to 1.9 GeV/c (0 to 1.5 GeV/c) in transverse momentum and from ?0.05 to 0.95 (?0.05 to 0.4) in Feynman x for protons (anti-protons), respectively. p _T integrated neutron cross sections are given in the interval from 0.1 to 0.9 in Feynman x. The data are compared to a wide sample of existing results in the SPS and ISR energy ranges as well as to proton and neutron measurements from HERA and RHIC.     

Inelastic interactions of protons with photoemulsion nuclei at 4·5 GeV/c

In inelastic collisions of protons with photoemulsion nuclei at 4·5 GeV/c, data have been obtained on multiplicity of shower particles, energy spectrum of fast secondary protons with (2·5±0·1) GeV average energy, and energy spectrum of produced charged pions with (640±±50) MeV average energy. The multiplicity, angular distributions, and energy of particles arising from splitting target-nuclei are also determined: the proton spectrum is approximated by the power dependenceE ^- with=1·4±0·1. The distribution of protons and-mesons over rapiditiesy=0·5 In[(E+p)/(E–p)] have been obtained. The average multiplicity for secondary particles coincide with the predicted values given by the cascade-evaporation model.Dedicated to the 25th anniversary of the Joint Institute for Nuclear Research.The authors would like to express their gratitude to the synchrophasotron group of JINR and to the group of S. J. Ljubomilov for the assistance in the experiment, to V. S. Barashenkov and V. V. Ivanov for the assistance in the cascade-evaporation model calculations, and also to the laboratories which took part in the scanning and measurement.     

Observation of the dependence of the interference effect of identical pions on pion pair velocity in inclusive ¯pp-interactions at 22·4 GeV/c

The Bose-Einstein interference effect is studied using 7333 events of ¯pp-interactions withn _ch6 at 22·4 GeV/c. An essential dependence of the strength of this effect on the pion pair velocity is observed. An indication is obtained that processes with essentially different time characteristics (<1 fm and >2 fm) contribute to ¯pp-interactions at 22·4 GeV/c. The interpretation based on abundant resonance production in high energy collisions is discussed.Dedicated to the 25th anniversary of the Joint Institute for Nuclear Research.     

Angular dependence of Bose-Einstein correlations in interactions of π+ andK + mesons with protons and nuclei at 250 GeV/c

The angular dependence of Bose-Einstein correlations is studied in interactions of ⁺ andK ⁺ mesons with protons and nuclei at 250 GeV/c. The pion source is found to be elongated along the interaction axis in the c.m.s., with the ratioa between transverse and longitudinal dimension equal to 0.55±0.06 for the case of proton, 0.53±0.13 for the case ofAl and 0.33±0.21 for the case ofAu target. For meson-proton interactions, indication for an increase of the elongation is found with increasing event multiplicity, pair momentum and particle transverse momentum.Now at UIA, Wilrijk, Belgium     

Cross sections of the interactions of4He nuclei with protons at 8·6 and 13·6 GeV/c

⁴He-p collisions at two values of⁴He momenta-8·6 GeV/c and 13·6 GeV/c — have been studied using the one-metre JINR hydrogen bubble chamber. Total, elastic and topological cross sections have been measured. The results are in agreement with other published data. The elastic differential cross section was compared with the predictions of the Glauber model formalism.Dedicated to Academician Václav Votruba on ths occasion of his eightieth birthday.We would like to thank Mrs. M. Stehlíková for drawing the figures.     

TheA-scaling of the multiplicity distributions ofπ ′,K − and\bar P interactions with nuclei at 40 GeV/c

The multiplicity distributions of charged particles produced from π^?,K ^? and \(\bar p\) interactions with the nuclei Li, C, S, Cu, CsI, Pb at 40 GeV/c were studied. It was found that the linear relationD=a〈n〉+b is satisfied for the distributions of different kinds of secondary particles including knocked out protons. Consequently, the use of the scaling variablez′=(an+b)/(a〈n〉+b) ensures the scaling of the distributions with respect to the mass numberA at least up to the second moment.     

1GeV/c广量程磁谱仪

本文简要叙述1GeV/c广量程磁谱仪的结构,包括谱仪磁铁系统和探测器及数据获取系统.推导了在扩展边缘场情况下,非聚焦型磁谱仪的动量公式.用蒙特卡罗方法计算了该谱仪的动量分辨、立体角和动态范围等参数.讨论了多次散射和探测器位置分辨对谱仪动量分辨的影响.     

Evidence for the production of thermal muon pairs with masses above 1 GeV/c 2 in 158 A GeV indium-indium collisions

The yield of muon pairs in the invariant mass region 1<M<2.5 GeV/c ² produced in heavy-ion collisions significantly exceeds the sum of the two expected contributions, Drell-Yan dimuons and muon pairs from the decays of D meson pairs. These sources properly account for the dimuons produced in proton-nucleus collisions. In this paper, we show that dimuons are also produced in excess in 158 A GeV In-In collisions. We furthermore observe, by tagging the dimuon vertices, that this excess is not due to enhanced D meson production, but made of prompt muon pairs, as expected from a source of thermal dimuons specific to high-energy nucleus-nucleus collisions. The yield of this excess increases significantly from peripheral to central collisions, both with respect to the Drell-Yan yield and to the number of nucleons participating in the collisions. Furthermore, the transverse mass distributions of the excess dimuons are well described by an exponential function, with inverse slope values around 190 MeV. The values are independent of mass and significantly lower than those found at masses below 1 GeV/c ², rising there up to 250 MeV due to radial flow. This suggests the emission source of thermal dimuons above 1 GeV/c ² to be of largely partonic origin, when radial flow has not yet built up.     

\bar K K and\bar p p off-shell annihilations fromK − +p → Λ + pions at 4.2 GeV/c

We have investigated the properties of off-shell \(\bar K\) K and \(\bar p\) p annihilations into pions by using the interactionsK ^? p → Λ + pions at 4.2 GeV/c. The properties considered are multiplicities, hadronic temperatures and angular distributions. These properties appear more akin to those of \(\bar p\) p annihilations in flight than to that of \(\bar p\) p annihilation at rest despite the fact that the annihilation energy is small.     

Inclusive production of charged kaons in p+p collisions at 158 GeV/c beam momentum and a new evaluation of the energy dependence of kaon production up to collider energies

New data on the production of charged kaons in p+p interactions are presented. The data come from a sample of 4.8 million inelastic events obtained with the NA49 detector at the CERN SPS at 158 GeV/c beam momentum. The kaons are identified by energy loss in a large TPC tracking system. Inclusive invariant cross sections are obtained in intervals from 0 to 1.7 GeV/c in transverse momentum and from 0 to 0.5 in Feynman x. Using these data as a reference, a new evaluation of the energy dependence of kaon production, including neutral kaons, is conducted over a range from 3 GeV to $\mathrm{p}+\overline{\mathrm{p}}$ collider energies.     

Neutral strange particle production inK + andπ + collisions with Al and Au nuclei at 250 GeV/c

Data are presented on inclusiveK _s ⁰ and production inK ⁺ and ⁺ collisions with Al and Au nuclei at 250 GeV/c. Results are given on total inclusive cross sections and theA dependence, as well as on distributions in Feynman-x _F , rapidityy and transverse momentum. Ratios ofK _S ⁰ and of to ⁺ production are presented. The data are compared with predictions of the quark-parton model FRITIOF.