Multiplicity Distributions Of Shower Particles Research Articles

Some Characteristics of Secondary Particles Produced in Pion-Nucleus Collisions in Emulsion at 50 GeV/c

In the present work we report some results on multiparticle production in 50 GeV/c π--interactions with emulsion nuclei. The general characteristics of heavy and shower particle multiplicity distributions are compared with the results from p-nucleus collisions at the same incident energy. The various experimental results have also been compared with the predictions of the existing theoretical models. We have observed that the mean normalized multiplicity (RA2) in hadron-nucleus interactions as a function of the effective number of projectile encounters, ⟨ν'⟩, calculated by using the additive quark model suggests a new kind of scaling and RA2 vs. ⟨ν'⟩ is independent of nature of the projectile.

A phenomenological investigation of the shower particle pseudorapidity fluctuations in hadron-nucleus collisions

From the experimental matrix ƒ(N g ; n s , Δη i) (the number of events with a given number N g of particles with velocity 0.3 c< v<0.7 c, and n s, the number of shower particles ( v > 0.7 c) in a pseudo-rapidity interval Δη i ) obtained from the Heidelberg-Igel hadron-nucleus experiment at CERN, we extract the shower particle multiplicity distributions as a function of ν, the number of nucleons that interacted with the projectile. We use a theoretically justified statistical correlation between ν and N g (recoil protons) and the assumption that the correlation between n s and N g is given merely through ν. The data used are for incoming energies 50 and 150 GeV with a proton or pion as the projectile and Cu or Pb as the target. We find that the shower particle multiplicity distributions are of a Poissonian character in each η bin and for each value of ν. The average multiplicities 〈n s 〉(ν) Δη i are approximately the same for the two targets and for the different projectile, possibly with a small excess for the pion projectile. The results are compared to a rather general theoretical model of the soft interaction type. The predictions from this model for the shower particle pseudorapidity distributions are very close to the derived values.

A study of inelastic pion-nucleus interactions at 200 GeV/ c in an emulsion

Results from a study of π-nucleus interactions in emulsion, at an incident momentum of 200 GeV/ c are presented and discussed. Some characteristics of heavy and shower-particle multiplicity distributions are reported and compared with the results from p-nucleus collisions at the same momentum. The angular distributions of shower particles are reported and analyzed in detail. It is shown, particularly, that one-particle distributions, being plotted in terms of pseudorapidity, have a bimodal structure in πA interactions. Also, pseudorapidity and azimuthal two-particle correlations are investigated. Considerable attention has been devoted to the exclusion of kinematical and trivial correlations. A qualitative comparison of the data with predictions of some model approaches has been performed.

Scaling of multiplicity distributions fromp-nucleus collisions in emulsion at energies between 6.2 and 300 GeV

The Koba-Nielsen-Olesen semi-inclusive scaling hypothesis has been tested for the two nearly homogeneous groups of target nuclei in nuclear emulsion. It is shown that the value of the parameter $\ensuremath{\alpha}$ in the scaling function used by Buras et al is close to zero for the emulsion data, regardless of the size of the target nucleus. The experimental shower-particle multiplicity distributions from proton-emulsion experiments are found to be consistent with the scaling hypothesis from 300 GeV down to 6.2 GeV.

Multiplicity of charged particles in π−-carbon interactions from 4 to 40 GeV/ c

We have measured the multiplicities of secondary charged particles produced in the collisions of π − mesons with carbon nuclei at momenta of 4.0, 5.0, 7.5 and 40.0 GeV/ c. The distribution of the number of visible protons does not change with the primary energy. There is observed an anomaly around n S = 3–4 for the multiplicity distribution of shower particles at 40 GeV/ c. Both the average multiplicities of shower and negative particles increase logarithmically with the momentum of the primary π − meson. The multiplicity of secondaries obeys KNO scaling. There are correlations, increasing with energy, between average multiplicities of charged fast particles and the number of slow protons. The presented experimental data are analyzed in the framework of new models proposed for inelastic hadron-nucleus collisions.