A model for inclusive production from high-energy hadron-nucleus interactions

It is shown that all aspects of the data on inclusive single-particle production from nuclei can be understood in terms of a model in which the interaction with the nucleus occurs through one or more elastic q-q scatterings. Successive scatters areassumeed to be mostly incoherent. No cascading occurs because “dressing” of the scattered quarks does not take place until after the quarks leave the nucleus.     

The energy and angular spectra of grey particles in high-energy hadron-nucleus interactions

A simple Monte Carlo model giving energy and angular spectra of the knocked out nucleons in the high energy hadron-nucleus interactions is described. The only input of the approach consists of some constants from the nuclear and high energy hadron-hadron phenomenology and without any adjustable parameters the model well reproduces substantial features of the experimental data.     

Long-range correlations in hadron-nucleus interactions

An analysis of correlations in rapidity of charged particles produced in proton and antiproton interactions on hydrogen, argon and xenon at 200 GeV is presented. Positive long-range correlations are observed in interactions on heavy targets. The dependence of rapidity correlations between the forward and backward hemisphere on the number of projectile collisions is discussed.     

Possible odderon effects in inclusive hadron production

We consider the possible contribution of odderon (reggeon with α _Odd(0)∼1 and negative signature) exchange to the differences in the inclusive spectra of particle and antiparticle in the central region. The energies and/or accuracy of the currently available experimental data do not allow for a clear conclusion on the presence of an odderon component, but the upcoming LHC data should finally elucidate the question of the existence of the odderon.     

High-energy hadron production and inclusive reactions

Recent data on multiparticle production at high energies are reviewed. The major topics include exclusive analyses, multiplicity distributions, single-particle inclusive spectra, and correlations. An effort is made to explore the physical significance of these results.     

Length of the formation zone from inclusive hadron-nucleus collisions

It is proposed to study the length of the formation zone by measuring theA-dependence and the energy-dependence of inclusive processes in projectile fragmentation region. The sensitivity of the method is studied, as well as its dependence on the underlying reaction mechanism.     

Multiplicities in highp t hadron-nucleus interactions

We present results obtained in π^? A (A=C, Cu, Pb) — collisions at 38 GeV/c. A single particle trigger selects events with one charged particle in the central region and large transverse momentum. The effect of this trigger on the multiplicities of all charged particles and of protons is shown.     

Particle production in high-energy hadron-nucleus interactions

The pseudorapidity (η) distributions of fast particles (β>0.7) emitted in inelastic hadron interactions with carbon, copper and lead were measured for incoming energies from 50 to 150GeV at the CERN Super Proton Synchrotron. Their dependence on target mass (A) and projectile (h) obeys <v>-scaling as expected. Their energy dependence is in contrast with most model predictions.     

On the observability of direct photons in ultrarelativistic nucleus-nucleus collisions by means of inclusive photon and hadron spectra

A method is presented to search for a direct photon signal in collisions between nuclei at ultrarelativistic energies. In the proposed method the analysis is performed in the center of momentum system of the radiating system, being the cms of the colliding nucleons in case of collisions of symmetric systems. This results in a maximal strength of a possible direct photon signal in the observed energy spectra, since the smearing of the signal due to the Lorentz transformation between the cms and the laboratory frame in case of fixed target experiments is absent. The feasibility of detecting a direct photon signal is examined by comparison of calculated photon and hadron spectra for central and peripheral ³²S on S collisions at a nucleon-nucleon cms energy of about 20 GeV, being the energy domain of the CERN-SPS fixed target experiments.     

The nuclear response in high-energy hadron-nucleus interactions

In an experiment at the CERN Super Proton Synchrotron (SPS) studying hadron-nucleus interactions, slow particles which are mainly knockout protons were measured with an electronic detector. Their dependence on the target mass, incoming energy, and projectile is shown. We discuss the use of the number of protons as a measure for the number of interactions of the projectile and conclude that the emitted protons measure the impact parameter of the reaction.     

High-twist correction for inclusive hadron production in photon-photon collisions

The contribution of the QCD high-twist subprocess γq→πq′ to the inclusive cross section for e⁺ e^? → e⁺ e^? + π^± + X is calculated both in the PETRA/PEP and the LEP energy range, in the equivalent-photon approximation. Superposed on the Born cross section and its O(α_s) correction, it gives agreement with the data at relatively low transverse momenta. It is suggested that this high-twist contribution may be further isolated experimentally by triggering simultaneously on both a fast hadron and the opposite-side jet.     

Chiral symmetry restoration in hadron spectra

The evidence and the theoretical justification of chiral symmetry restoration in high-lying hadrons is presented.     

Hump-backed QCD plateau in hadron spectra

New data on inclusive energy distribution of hadrons from quark jets ine ⁺ e ^? annihilation are shown to agree with the quantitative predictions of perturbative QCD, supporting the hypothesis of local parton-hadron duality.     

Mechanism of single-spin asymmetries generation in the inclusive hadron processes

We discuss a nonperturbative mechanism for generation of the single-spin asymmetries in hadron interactions. It is based on the chiral quark model combined with unitarity and impact parameter picture and provides explanation for the experimental regularities observed under the measurements of the spin asymmetries.     

Multifractal thermodynamics of hadron-hadron and hadron-nucleus interactions

It is shown that the constant-specific-heat approximation is applicable to multifractal thermodynamics of hadron-hadron and hadron-nucleus interactions at high energies. Moreover, the constant specific heats calculated from experimental data on hadron-hadron and hadron-nucleus interactions have approximately the same value for both these types of multifractal multiproduction. Thus this parameter may turn out to be an universal characteristic of the hadron-hadron and hadron-nucleus interactions. Some relationship of this phenomenon to multifractal thermodynamics at the onset of chaos is briefly discussed. Received: 16 December 1997 / Revised version: 2 April 1998     

Backward hadron production in neutrino-nucleus interactions

The production of backward pions in lepton-nucleus collisions is analyzed. We show that a large yield of high momentum backward pions can be explained by the Regge asymptotic of the distribution of nucleons carrying a large momentum fraction in the nuclear target. The calculated spectra of pions emitted in the ν+ Ne →μ+π⁻+ X and ν+²H →μ+π⁻+ X reactions are in satisfactory agreement with the available experimental data. Received: 22 July 1999 / Revised version: 22 November 1999     

Energy dependent growth of nucleon and inclusive charged hadron distributions

In the Color Glass Condensate formalism, charged hadron p T spectra in p+p and p+Pb collisions are studied by considering an energy-dependent broadening of nucleon density distribution. Then, in the glasma flux tube picture, the n-particle multiplicity distributions at different pseudo-rapidity ranges are investigated. Both the theoretical results show good agreement with the recent experimental data from ALICE and CMS at LHC energies.The predictive results for p T or multiplicity distributions in p+p and p+Pb collisions at the Large Hadron Collider are also given in this paper.     

J/ψ能区强子单举产生的实验研究

利用北京谱仪(BES)获取的2×10⁵ J/ψ事例,首次给出J/ψ能区π^±、π⁰、K^±、K⁰_s、ρ⁰.K^*0、K^*±、φ等介子和p、Ξ^±、Σ^±(1385)等重子的单举产额,并与理论模型进行比较,结果表明唯象模型向低能区的延拓是可行的. 同时得到J/ψ能区的奇异抑制因子s/u ～0.3,自旋抑制因子V/(V+P)～0.3—0.5,与ARGUS在Υ能区的测量结果一致,说明SU(6)对称性破缺在J/ψ能区也是存在的.     

Dual properties of inclusive spectra

The dual properties of the inclusive reaction π^?p → pX are studied over a wide energy range by exploiting the scaling behaviour. Semi-local duality is found to be well satisfied. An energy-dependent triple-Regge analysis reveals a strong triple-pomeron coupling. There is some evidence of an abnormal component in which diffractively produced resonances are dual to pomeron exchange. Combining duality with factorization leads to relations between production cross sections of meson and baryon resonances in πp and pp collisions, which are compatible with existing experimental data.