Probing the light Higgs pole resonance annihilation of dark matter in the light of XENON100 and CDMS-II observations
We consider the prospect of lightest neutralino (χ 0 1 ) as a dark matter candidate in light of recent interesting observations from the XENON100 and CDMS-II experiments in minimal supergravity framework with large tanβ and nonvanishing A 0 . Within the WMAP satisfied zone, there is a large direct detection reach of lighter χ 0 1 in the lighter Higgs boson mediated resonance annihilation domain of the above scenario. It is seen that the heavier Higgs boson plays a dominating role in the χ 0 1 - p cross section in the associated zone of parameter space in spite of having a larger mass. Possible LHC signatures are discussed.

title: Working group report: Physics at the Large Hadron Collider
abstract: This is a summary of the activities of the Physics at the LHC working group in the XIth Workshop on High Energy Physics Phenomenology (WHEPP-XI) held at the Physical Research Laboratory, Ahmedabad, India in January 2010. We discuss the activities of each sub-working group on physics issues at colliders such as Tevatron and Large Hadron Collider (LHC). The main issues discussed involve (1) results on W mass measurement and associated QCD uncertainties, (2) an attempt to understand the asymmetry measured at Tevatron in the top quark production, and (3) phenomenology of warped space dimension model.

title: Study of single sneutrino production in association with fermion pairs at polarized photon colliders
abstract: We investigate single sneutrino production in the context of R-parity-violating supersymmetry at future ?? linear colliders. The sneutrino is produced in association with fermion pairs and it is shown that its decays into two further fermions will lead to a clean signal. We also discuss possible standard model backgrounds and the effects of beam polarization.

title: Signals for gauge mediated supersymmetry breaking model at an e−e− collider
abstract: We study the pair-production and decay of right handed selectrons within a Gauge Mediated Supersymmetry Breaking Model in polarised e−e− interaction. Detailed analyses of the possible signals and backgrounds are performed for a few selected points in the parameter space. A judicious choice for polarisation of the initial electron beam helps eliminate almost the entire Standard Model background. We also show that phase space distributions can be used to distinguish such a supersummetry breaking scheme from the supergravity inspired models.

title: Constraining anomaly mediated supersymmetry breaking framework via ongoing muon g − 2 experiment at Brookhaven
abstract: The ongoing high precision E821 Brookhaven National Laboratory experiment on muon $g\ensuremath{-}2$ is promising to probe a theory involving supersymmetry. We have studied the constraints on the minimal anomaly mediated supersymmetry breaking (AMSB) model using the current data of muon $g\ensuremath{-}2$ from Brookhaven. A scenario of seeing no deviation from the standard model is also considered, within a $2\ensuremath{\sigma}$ limit of the combined error from the standard model result and the Brookhaven predicted uncertainty level. The resulting constraint is found to be complementary to what one obtains from $\stackrel{\ensuremath{\rightarrow}}{b}s+\ensuremath{\gamma}$ bounds within the AMSB scenario, since only a definite sign of $\ensuremath{\mu}$ is effectively probed via $\stackrel{\ensuremath{\rightarrow}}{b}s+\ensuremath{\gamma}.$ A few relevant generic features of the model are also described for disallowed regions of parameter space.

title: Invisible decays of Higgs and other mesons in models with singlet neutrinos in large extra dimensions
abstract: In light of current atmospheric neutrino oscillation data, we revisit the invisible decay of the standard model Higgs boson and other pseudoscalar mesons which can be enhanced because of large number of KK modes in models with right-handed singlet neutrinos in large extra dimensions. We find that the invisible decay rate of Higgs can be as large as H→b b decay rate only for a very restricted region of parameter space. This parameter space is even further restricted if one demands that the dimensionless neutrino Yukawa coupling λ is O (1). We have also studied the scenarios where singlet neutrino propagate in a sub-space, which lowers the string scale M ∗ and keeps neutrino Yukawa coupling O (1). We have also considered decays of other spin-0 mesons to ν ν and found the rates to be too small for measurement.

title: Characteristics of pion production in ring-like events using entropy index
abstract: The possible chaotic behaviour in production of ring like structured events and jet like structured events in 16 O-AgBr interactions at 60 AGeV with the help of a newly defined parameter, entropy index μ′q has been studied. The data reveal less chaoticity in the pionisation process of ring like events with respect to that of jet like events.

title: Multiplicity scaling of target protons in high-energy nucleus-nucleus and hadron-nucleus interactions
abstract: Multiplicity scaling of target protons emitted from nucleus?nucleus (16O?AgBr interactions at 2.1 AGeV and 32S?AgBr interactions at 200 AGeV), pion?nucleus (???AgBr interactions at 350 GeV/c) and proton?nucleus interactions (p?AgBr interactions at 200 GeV/c) has been investigated. The experimental points are found to lie approximately on the curve described by ?(z) = Azexp?( ? Bz) with A = 3.36 ? 0.19 and B = 1.74 ? 0.06 for all the four interactions. A comparison of the fit with the function ?(z) = (Az + Bz3 + Cz5 + Dz7)exp?( ? Ez) has also been performed.

title: Characteristics of multiplicity distribution of target fragments in forward and backward hemispheres in high-energy nucleus–nucleus interactions
abstract: A detailed study on the mechanism of the evaporation of target fragments in the forward and backward hemispheres in 12C–AgBr interactions at 4.5A GeV, 28Si–AgBr interactions at 14.5A GeV, 16O–AgBr interactions at 60A GeV and 32S–AgBr interactions at 200A GeV is carried out in terms of the multiplicity distribution. The nature of the multiplicity distribution in the forward and backward hemispheres is found to be different across all the interactions. The asymmetry parameters and the forward–backward ratios were also calculated for the above-mentioned interactions. The asymmetry parameters and the forward–backward ratios from other nucleus–nucleus interaction data were compared with our results. The forward–backward ratios of target fragments are found to be nearly the same for all the nucleus–nucleus interactions. The forward–backward ratios of all the interactions are greater than 1, suggesting that the probability of emission of fragments in the forward hemisphere is higher than that in the backward direction. The multiplicity moment, entropy and reduced entropy, i.e. the ratio of entropy to average multiplicity of target fragments, are evaluated in both the forward and backward hemispheres for all the four above-mentioned interactions. The values of multiplicity moments are found to be energy independent up to 60A GeV energy in the backward hemisphere. The reduced entropy is also found to be almost energy independent to within experimental error in the backward hemisphere. No such observation can be made in the forward hemisphere. The total entropy of the target fragments is found to be higher in the forward hemisphere. A study of correlation in terms of the scaled variance was also carried out in both the hemispheres for all the nucleus–nucleus interactions. No systematic variation of correlation either with energy or with the size of the projectile nucleus has been noticed. The study yields quite interesting information on the mechanism of particle evaporation in the backward hemisphere.

title: Quantitative estimate of pion fluctuation and its multiplicity dependence in nuclear collisions
abstract: This paper presents the results of an investigation on the multiplicity dependence of the fluctuation pattern of pions for the entire accelerator energy range from 2.1 to 200 AGeV. The data set for produced pions is divided into four sets depending on the number of shower tracks ns. Analysis is carried out in two-dimensional η– space with the Hurst exponent to take care of the anisotropy of the phase space. The Hurst exponent is extracted by fitting one-dimensional factorial moment saturation curves to Ochs' saturation formula. The values of the effective fluctuation strength α eff are estimated and multiplicity dependence is studied w.r.t. α eff and the Hurst exponent H. It is highly interesting to observe that both fluctuation strength and degree of anisotropy (characterized by H) depend on pion multiplicity. The multiplicity dependence is more pronounced at lower projectile energy. The results of the study are discussed in detail.

title: Multifractal detrended fluctuation analysis of pseudorapidity and azimuthal distribution of pions emitted in high energy nuclear collisions
abstract: In this paper multifractal analysis of fluctuation pattern of pions emitted in 32S-AgBr and 16O-AgBr interactions at 200 GeV and 60 GeV, respectively, is performed in the framework of multifractal detrended fluctuation analysis (MFDFA). The pseudorapidity and azimuthal distributions exhibit multifractal scaling properties at both energies. The variation of multifractal width with energy is also studied. The study reveals a dependence of multifractal width on energy in pseudorapidity space while no such dependence is observed in azimuthal space.