Jaya Roy

Study on fractility in nucleus-nucleus interaction at a few GeV/c

Abstract The scaled factorial moments, F q and fractal moments, G q have been measured and their power law variation as a function of size of the pseudorapidity interval has been studied in the central region of the pseudorapidity distribution of the produced charged particles in quasi-central and central collisions of 16 O + Ag Br at 2.1 GeV c per nucleon and 24 Mg + Ag Br at 4.5 GeV c per nucleon. The smooth spectral function f ( α q ), characterizing the fluctuation in the pseudorapidity distribution and the generalised dimensions D q have been derived from G q moments. The analyses reveal a self-similarity in multiparticle production in nucleus-nucleus interactions at an incident momentum of a few GeV/ c per nucleon. Interesting observations can be very effective in establishing multifractality in multiparticle production at this energy range.

Multiplicity characteristics of heavy-ion interactions at 4.5GeV/yc per nucleon

Abstract This paper presents exhaustive, new data on the shower and compound multiplicity charactersties of 24 Mg-emulsion and 12 C-emulsion interactions at incident momentum of 4.5 GeV/ c per nucleon. A comparative study is made (whenever possible) with p-emulsion interaction data at the same incident momentum per nucleon. The linear dependences of different multplicities on shower and compound multiplicity, e.g., 〈 n i 〉 = a ij + k ij n j -( i ≠ j ), are also shown in this paper.

Study of multiparticle production in the interaction of 12C with photoemulsion nuclei at 4.5 GeV/c per nucleon

Abstract The paper presents exhaustive data on the interaction of 12 C-emulsion at 4.5 GeV/ c per nucleon. It deals with the multiplicity characteristics, i.e. multiplicity distribution, multiplicity correlation, mean multiplicity for the secondary particles, shower and compound (grey + shower) multiplicity scaling. We also discuss in this paper two-particle pseudorapidity correlations including a Monte Carlo simulation for comparison and the azimuthal angle dependence on it. A comparative study with the proton-emulsion interaction data at the same initial momentum, wherever possible, is also done.

The validity of the negative binomial multiplicity distribution in the case of the relativistic nucleus-nucleus interaction

Abstract This letter presents new data on the multiplicity distribution of charged secondaries in 24 Mg interactions with AgBr at 4.5 GeV/ c per nucleon. The validity of the negative binomial distribution (NBD) is studied. It is observed that the data can be well parametrized in terms of the NBD law for the whole phase space and also for different pseudo-rapidity bins. A comparison of different parameters with those in the case of h-h interactions reveals some interesting results, the implications of which are discussed.

ZONAL POISSONIAN PION MULTIPLICITY IN CENTRAL 24Mg-AgBr COLLISIONS AT DUBNA ENERGY

This paper reports a study on the coherent production of pions in central 24Mg-AgBr collisions at 4.5 GeV/c per nucleon. The analysis is based on a comparison of experimental multiplicity distribution in different pseudo rapidity bins with Poissonic distributions. It has been observed that pion multiplicity is Poissonian in some specific zone. The physical implication is also discussed.

Study of the Cluster Characteristics in Hadron-Nucleus Interactions at Ultrahigh Cosmic Ray Energies

In this paper we have presented an investigation of cluster characteristics in nucleon-light nucleus and nucleon-heavy nucleus collision in emulsion at ultrahigh cosmic ray energies (above 1 TeV) following a model independent method proposed in a recent paper by Shivpuri et al. It has been observed that the cluster characteristic in both are not very different from those in case of nucleon-nucleon collision.

Observation of hot and cold events in the 12C-emulsion interaction at 4.5 GeV/c per nucleon-a signal for quark matter formation?

The authors present a study of the transverse momentum distribution of relativistic alpha particles emerging from the interaction of 12C and emulsion at 4.5 GeV/c per nucleon. A large statistics study of 1200 events when compared with the Maxwell-Boltzmann distribution reveals the existence of two temperatures, a hot and a cold, since a single Maxwell-Boltzmann distribution cannot fit the peak and the tail simultaneously. This yield of two distinctly different temperatures in the fragmentation region may be interpreted as a possible signal for the formation of a quark-gluon plasma.

INTERMITTENCY IN HADRON-NUCLEUS INTERACTIONS AT 200 GeV/c IN TERMS OF FACTORIAL CORRELATORS

Factorial Correlators (FCs), a tool for the test of “intermittency” in multiparticle production in high energy physics, has not been given much attention, compared to the efforts towards understanding the phenomenon in terms of scaled factorial moments. So far, only hadron-hadron data of NA22 collaboration and nucleus-nucleus data of EMU01 collaboration have been analyzed in terms of FCs. However, the present situation of intermittency study demands thorough exploitation of all the available tools for better understanding of the phenomenon. In this article we present the analysis of particle production data of hadron-nucleus interaction at 200 GeV/c in terms of FCs. The results of the analysis show a consistency with the prediction of α-model for the existence of “intermittency.”

Evidence of Fractality in Proton Emission in Nucleus-Nucleus Interactions

The method of scaled factorial moments is used to study non-statistical fluctuations present in the emission process of the medium-energy protons, emitted in nucleus-nucleus interactions, in terms of their emission angle (?). The investigation has been done with our data of 24Mg-Ag/Br interaction at 4.5?GeV/c/n and 16O-Ag/Br interaction at 2.1?GeV/n. Corrections have been made for the non-uniformity of the distribution of the variable used for the purposes of analysis. A power law growth of the corrected moments with decreasing bin size suggests an intermittent behaviour in both the cases. Multifractal analysis in terms of fractal moments, Gi, has also been performed, which reveals hint of multifractality in the emission process.

Evidence of different pion coherence zones for 'hot' and 'cold' events in relativistic heavy-ion interaction

A comparison of the transverse momentum (PT) distribution of the alpha particles emitted as projectile fragments from the 12C-emulsion interaction at 4.5 GeV c-1 with the double Maxwell-Boltzmann distribution yields two temperature in the projectile fragmentation region (10 MeV and 40 MeV). This work reports a study on the coherence of pion production for two classes of events-cold (10 MeV) and hot (40 MeV). The data show an interesting observation-in the case of cold events pions are produced coherently in a specific pseudo-rapidity region, whereas pion production is extremely incoherent for hot events in that zone; it is coherent in a different pseudo-rapidity region.