Higher order correlation of the pions and their target excitation dependence in relativistic and ultrarelativistic nuclear collisions
The target excitation dependence of higher order correlation of the pions is investigated in the present work using the data of 16O–AgBr interactions at 2.1 and 60 A GeV and 32S–AgBr interactions at 200 A GeV. The data are divided into different sets of ng which correspond to different degrees of the target excitation. The target excitation dependence was evident at the lower projectile energy—at the higher projectile energy no target excitation dependence was revealed by the data.

title: NON-STATISTICAL FLUCTUATIONS OF PIONS FOR RING- AND JET-LIKE EVENTS AT CERN SPS ENERGY — AN IN-DEPTH ANALYSIS WITH FACTORIAL CORRELATOR
abstract: This study reveals the analysis of ring-like and jet-like events in terms of factorial correlations of 16O–Ag/Br interactions at 60A GeV. The investigation revealed that the correlated moments are found to increase with decreasing bin–bin separation D and follows a power-law which suggests the presence of an intermittent nature of self-similar dynamical fluctuations pattern for ring-like and jet-like events. From the analysis we find that for jet-like events the strength of non-statistical fluctuation is greater than the ring-like and total event set. Jet-like events follow the bin size independence according to α model of intermittency as like total events, whereas ring-like events are not consistent with the prediction of α model of intermittency.

title: MULTIPLICITY DISTRIBUTION AND MULTIPLICITY MOMENT OF BLACK AND GREY PARTICLES IN HIGH ENERGY NUCLEUS–NUCLEUS INTERACTIONS
abstract: In this paper we have studied the multiplicity distribution of black and grey particles emitted from 16O–AgBr interactions at 2.1 AGeV and 60 AGeV. We have also calculated the multiplicity moment up to the fifth order for both the interactions and for both kinds of emitted particles. The variation of multiplicity moment with the order number has been investigated. It is seen that in the case of black particles multiplicity moment up to fourth order remains almost constant as energy increases from 2.1 AGeV to 60 AGeV. Fifth order multiplicity moment increases insignificantly with energy. However in the case of grey particles no such constancy of multiplicity moment with energy of the projectile beam is obtained. Later we have extended our study on the basis of Regge–Mueller approach to find the existence of second order correlation during the emission of black as well as the grey particles. The second Mueller moment is found to be positive and it increases as energy increases in the case of black particles. On the contrary in the case of grey particles the second Mueller moment decreases with energy. It can be concluded that as energy increases correlation among the black particles increases. On the other hand with the increase of energy correlation among the grey particles is found to diminish.

title: Multiplicity fluctuations of pions and protons at SPS energy — An in-depth analysis with factorial correlator
abstract: We compute the factorial correlators to study the dynamical fluctuations of pions and a combination of pions and protons (compound multiplicity) in 32S-AgBr interactions at 200 A GeV. The study reveals that for both pion and compound multiplicity the correlated moments increase with the decrease in bin-bin separation D, following a power-law, which suggests the self-similarity of multiplicity fluctuation in each case. The results of the analysis also show a consistency with the prediction of α-model for the existence of intermittency in both cases.

title: Evidence of different reaction mechanisms for hot and cold events in relativistic heavy-ion interaction
abstract: This paper reports evidence of different reaction mechanisms for two classes of events, ''hot,'' and ''cold,'' in /sup 12/C emulsion at 4.5 (GeV/c)/N observed by Ghosh et al., from a comparison of the transverse-momentum (P/sub T/) distribution with a mixture of two Maxwell-Boltzmann distributions with different temperatures. The hypothesis is substantiated by the significant difference, for ''hot'' and ''cold'' events, in the values of the average number of pions produced, average emission angle of ..cap alpha..-projectile fragments, and ratio of yield of ..cap alpha.. particles to protons as projectile fragments.

title: Entropy scaling in high-energy nucleus–nucleus interactions
abstract: We studied the multiparticle production in high-energy nucleus–nucleus interactions in terms of particle entropy in 16O–AgBr and 32S–AgBr interactions at 60 A GeV and 200 A GeV, respectively. An approximate scaling behavior of total produced entropy normalized to maximum rapidity in the center of mass frame measured in different rapidity bins has been reported. The scaling behavior is not supported either by the FRITIOF model or by the Monte Carlo simulated events.

title: Summary of the Activities of the Working Group I on High Energy and Collider Physics
abstract: This is a summary of the projects undertaken by the Working Group I on High Energy Collider Physics at the Eighth Workshop on High Energy Physics Phenomenology (WHEPP8) held at the Indian Institute of Technology, Mumbai, January 5-16, 2004. The topics covered are (i) Higgs searches (ii) supersymmetry searches (iii) extra dimensions and (iv) linear collider.

title: Collider Signatures for Heavy Lepton Triplet in Type I+III Seesaw
abstract: The minimal SU(5) theory augmented by the fermionic adjoint representation restores the coupling constant unification and gives realistic neutrino masses and mixing through the hybrid Type I and Type III seesaw. The crucial prediction of the theory is an SU(2) lepton triplet with the mass below TeV. We study the signature of these heavy leptons and propose the strategy to test this mechanism at the hadron and lepton colliders. The smoking gun evidence of the theory is Delta L=2 lepton number violation through events of a pair of like-sign leptons plus four jets without significant missing energy at hadron colliders. We find that via this unique channel, the heavy lepton can be searched for up to a mass of 200 GeV at the Tevatron with 8 fb^-1, and up to 450 (700) GeV at the LHC of 14 TeV C.M.energy with 10 (100) fb^-1. The signal rate at the 10 TeV LHC is reduced to 60-35% for a mass of 200-700 GeV. We also comment on how to distinguish this theory from other models with similar heavy leptons. Finally, we compare the production rates and angular distributions of heavy leptons in e+e- collisions for various models.

title: Higgs pair production in association with a vector boson at e + e − colliders in theories of higher dimensional gravity
abstract: The models of large extra compact dimensions, as suggested by Arkani-Hamed, Dimopoulos and Dvali, predict exciting phenomenological consequences with gravitational interactions becoming strong at the TeV scale. Such theories can be tested at the existing and future colliders. In this paper, we study the contribution of virtual Kaluza-Klein excitations (both spin-0 and 2) in the process $e^+e^- \to HHZ$ and $ e^+e^- \to HH\gamma $ at future linear collider (NLC). We find that the virtual exchange KK gravitons can modify the cross-section $\sigma(e^+e^- \to HHZ)$ significantly from its Standard Model value and will allow the effective string scale to be probed up to 6.6 TeV. The second process is absent at the tree level in the standard model, and can therefore be used to put limits on the effective string scale of 7.4 TeV.

title: Implications of the 98 GeV and 125 GeV Higgs scenarios in nondecoupling supersymmetry with updated ATLAS, CMS, and PLANCK data
abstract: We discuss both MSSM and NMSSM scenarios in which the lightest Higgs boson with $m_h=98$~GeV is consistent with the small excess ($\sim 2.3 \sigma$) observed at the LEP in $e^+ e^-\rightarrow Zh$, with $h \rightarrow b {\bar b}$ process and the heavier Higgs boson of mass close to 125~GeV as the observed candidate of the SM Higgs like particle at the LHC. We show the allowed regions in the non-decoupling Higgs zone of MSSM parameter space which are consistent with several low energy constraints coming from heavy flavour physics, latest experimental data on Higgs signals and lower limit on superparticle masses from 7~TeV and 8~TeV LHC run. We also implement the constraints from the relic density of the cold dark matter as obtained from the recent PLANCK data. Additionally, we discuss the possibility of observing the light Higgs boson of mass 98~GeV at the 14~TeV LHC run via $pp \rightarrow V h$, with $h \rightarrow b \bar b$ using the technique of jet substructure. Our analysis shows that at 14~TeV LHC run with 300 ${\rm fb}^{-1}$ luminosity the signal efficiency of such a light Higgs boson is at most 2.5$\sigma$. Finally, we make a comment on the prospect of proposed $e^+ e^-$ ILC to discover/exclude this light Higgs boson.

title: R -parity violating supersymmetric explanation for the CDF W j j excess
abstract: Recently CDF has reported a 4.1 sigma excess in the distribution of the dijet invariant mass between 120-160 GeV in Wjj event sample in 7.3 fb^{-1} of data, which has generated considerable interest. We offer a possible explanation of this observation in the general framework of MSSM with R-parity violation through resonance production of tau sneutrino decaying into the LSP stau_1 and W boson. We also give the predictions of this scenario for the LHC operating at 7 TeV center of mass energy.