Event-by-event investigation of charged neutral fluctuations in heavy ion collisions using DWT technique

We present results on filtering events having nonstatistical charged neutral fluctuations using Discrete Wavelet Transforms(DWT). Pb-Pb 10⁵ events at 158 AGeV were generated using VENUS event generator and charged neutral fluctuations were injected event-by-event using simple DCC modeling. We also filtered events using DWT along with Sliding Window Method. The efficiencies and purities of samples extracted having nonstatistical charged neutral fluctuations using DWT and sliding DWT are presented.     

High energy proton emission in reactions induced by 315 MeV 16O ions

Inclusive proton spectra have been measured for the reaction ¹⁹⁷Au(¹⁶O, p)X at 315 MeV. The data, which are consistent with emission from a moving source, are compared with the fireball model and with models preequilibrium emission.     

Development of a honeycomb gas proportional counter array for photon multiplicity measurements in high multiplicity environment

A novel gas-based detector using large arrays of honeycomb cells has been developed and tested for use as a pre-shower photon multiplicity detector (PMD) for STAR and ALICE experiments. The appropriate cell design was arrived at using GARFIELD simulations. Prototype chambers with cell dimensions corresponding to STAR and ALICE were fabricated and tested at CERN PS and SPS. The charged particle detection efficiency and the pre-shower characteristics have been studied using pion and electron beams.     

Recent results from CERN SPS experiments and the future heavy ion programme

We describe the important results from the recent experiments using lead beams at the CERN SPS. The results of the WA98 experiment, which has substantial Indian participation along with the photon multiplicity detector is described in some detail. Combining the preliminary results from various experiments looking at different signals of phase transition, one finds enough evidences to suggest that phase transition has taken place in nuclear collisions at the SPS. Future programme of heavy ion physics at the LHC is being greared around the ALICE experiment. This will comprise of detector subsystems capable of studying almost all the signals in the same event. The photon multiplicity detector will be an important component of the ALICE experiment, being a totally Indian contribution to ALICE.     

Detectors for high energy nuclear physics experiments

High energy nuclear physics experiments started about a decade ago with the aim of studying quark gluon plasmas (QGP) in the laboratory. Statistical QCD predicts that in nuclear collisions at ultra-relativistic energies the quarks and gluons in hadrons will be momentarily deconfined into a phase of matter containing free quarks and gluons in the form of a plasma. This quark gluon plasma is also thought to have existed in the very early history of the evolution of the Universe, some 10 microseconds after the Big Bang when the extremely hot blob of energy started to cool and be converted into matter. Thus the study of ultra-relativistic nuclear collisions is important from the point of view of nuclear and high energy physics, astrophysics and cosmology. In these studies new detectors are required.