P.K. Sengupta

Charged particle multiplicity in 400 GeV/c p-nucleus interactions in nuclear emulsion

Abstract Experimental results of the interactions of 400 GeV/ c protons with emulsion nuclei are presented. It is observed that mean multiplicities for incoherent events are, 〈 N S 〉 = 17.00 ± 0.21, 〈 N h 〉 = 8.10 ± 0.20. The dispersion D = 1015 ± 0.19. Various linear relations between these parameters are discussed. The energy dependence of 〈 N S 〉 and the parameters R em , R eq and R 2 are also examined. It is observed that R em varies as A 0.16 .

Charm production in 400 GeV/c proton-emulsion interactions

Abstract 5032 proton-emulsion interactions at 400 GeV/ c momentum have been carefully scrutinized for production and decay of charged charm particles. In order to detect these decays, shower tracks from 3056 stars have been followed to a maximum length of 1 mm and those from 1976 stars up to 2 mm. A total of 23 three-prong charm-like candidates have been recorded in the forward cone. The background due to γ-overlap on a shower track, trident/pseudo-trident production and secondary interactions is estimated to be 15. Attributing the signal of 8 events to Λ c + and assuming the branching ratio of Λ c + → 3 prong to be 0.6 and τ Λ c to be 10 −13 sec we obtain the production cross section to be 106±39 μ b/nucleon. Out of these 8 events one example of semileptonic decay of Λ c + is seen.

Characteristics of p-N Interactions at 400 GeV/c in Emulsion

The angular and rapidity distributions of secondary charged particles from p-N interactions at 400 GeV/c for charged particle multiplicity ≥ 4 are presented. The forward-backward ratio in the centre of mass system is found to be 1.54 ± 0.07. The rapidity distribution shows a plateau in the central region with a mean value 3.81 ± 0.03. The study of rapidity dispersion indicates that in ~ 30% of the events single nova is produced.

Estimation of energy of the primary particle in hadron-nucleus interactions in

Abstract The recent methods of estimating the energy of the primary particle in hadron-nucleus interactions have been compared and tested by employing the experimental data on angular distributions from p-emulsion interactions at the highest available accelerator energy of 400 GeV. The method due to Bhowmik et al. has been found to give the best energy estimates for individual events. This method also yields plausible estimates of inelasticity and number of collisions inside the nucleus.

Multiperipheral Cluster Production at High Energies

The two-channel Chew-Pignotti mu\tiperipheral cluster model due to Snider has been tested on 67 GeV/c p-N data. The data strongly favour short-short correlations in the rapidity gaps. The cluster size and the cluster density in rapidity space are estimated to be 5.Z and 0.5 respectively. Comparison of the present results with those at higher energies indicates that the cluster size remains practically constant at a value 5~6 particles within the energy range 67~400GeV.

Energy estimation of photons in nuclear emulsions

Abstract A comparison is made of the three methods by Stearns, Borsellino and Olsen used for estimating the photon energy from the opening angle of the e + e − pair. It is found that Olsens method gives the most reliable estimate of photon energy.