Constraining anomaly mediated supersymmetry breaking framework via ongoing muon g − 2 experiment at Brookhaven
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: Stop and sbottom search using dileptonic MT2 variable and boosted top technique at the LHC
abstract: A bstractThe ATLAS and CMS experiments at the CERN LHC have collected about 25 fb−1 of data each at the end of their 8 TeV run, and ruled out a huge swath of parameter space in the context of Minimally Supersymmetric Standard Model (MSSM). Limits on masses of the gluino $ \left( {\widetilde{g}} \right) $ and the squarks of the first two generations $ \left( {\widetilde{q}} \right) $ have been pushed to above 1 TeV. Light third generation squarks namely stop and sbottom of sub-TeV masses, on the other hand, are still allowed by their direct search limits. Interestingly, the discovery of a Standard Model (SM) higgs boson like particle with a mass of ~ 125 GeV favours a light third generation which is also motivated by naturalness arguments. Decays of stop and sbottom quarks can in general produce a number of distinct final states which necessitate different search strategies in the collider experiments. In this paper we, on the other hand, propose a general search strategy to look for third generation squarks in the final state which contains a top quark in the sample along with two additional hard leptons and substantial missing transverse momentum. We illustrate that a search strategy using the dileptonic MT2, the effective mass meff and jet substructure to reconstruct the hadronic top quark can be very effective to reduce the SM backgrounds. With the proposed search strategy, we estimate that the third generation squarks with masses up to about 900 GeV can be probed at the 14 TeV LHC with 100 fb−1 luminosity. We also interpret our results in two simplified scenarios where we consider the stop (sbottom) pair production followed by their subsequent decay to a top quark and the second lightest neutralino (lightest chargino). In this case also we find that stop (sbottom) mass up to 1 TeV (0.9 TeV) can be discovered at the 14 TeV LHC with 100 fb−1 integrated luminosity.

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 A GAUGE MEDIATED SUPERSYMMETRY BREAKING MODEL AT A FUTURE e-e- COLLIDER
abstract: We study the pair-production and decay of right selectrons of a Gauge Mediated Supersymmetry Breaking Model in the polarised e-e- interaction. Detailed analyses of the possible signals and backgrounds are performed for five selected points in the parameter space. We also show that judicious choice of polarisation of the initial electron beam can almost kill the possible Standard Model backgrounds.

title: Dynamical R-parity breaking at the LHC
abstract: In a class of extensions of the minimal supersymmetric standard model with (B-L)/left-right symmetry that explains the neutrino masses, breaking R-parity symmetry is an essential and dynamical requirement for successful gauge symmetry breaking. Two consequences of these models are: (i) a new kind of R-parity breaking interaction that protects proton stability but adds new contributions to neutrinoless double beta decay and (ii) an upper bound on the extra gauge and parity symmetry breaking scale which is within the large hadron collider (LHC) energy range. We point out that an important prediction of such theories is a potentially large mixing between the right-handed charged lepton (ec) and the superpartner of the right-handed gauge boson $ \left( {\tilde{W}_R^{+} } \right) $, which leads to a brand new class of R-parity violating interactions of type $ {\tilde{\mu }^{{c^\dag }}}\nu_\mu^c{e^c} $ and $ {\tilde{d}^{{c^\dag }}}{u^c}{e^c} $. We analyze the relevant constraints on the sparticle mass spectrum and the LHC signatures for the case with smuon/stau NLSP and gravitino LSP. We note the “smoking gun” signals for such models to be lepton flavor/number violating processes: pp!μ±μ±e+e-jj (or τ±τ±e+e-jj) and $ pp \to {\mu^\pm }{e^\pm }b\overline b jj $ (or $ {\tau^\pm }{e^\pm }b\overline b jj $) without significant missing energy. The predicted multi-lepton final states and the flavor structure make the model be distinguishable even in the early running of the LHC.

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.

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: Evidence of multifractality and constant specific heat in hadronic collisions at high energies

title: Chaos analysis of nuclear fragments in high energy collisions
abstract: This paper deals with fixed target AGS and SPS data of beam energies 14.5 and 200 A GeV respectively. A detailed study on chaos in the nuclear fragmentation process of 28Si–AgBr interactions at 14.5 A GeV and 32S–AgBr interactions at 200 A GeV has been performed using a new parameter, the entropy index. The analysis provides new data on the evidence of the erratic behavior of the target fragments signifying chaotic target fragmentation and also quantify the measure for chaos in high and ultra-high energy heavy-ion interactions. Further, it is also observed that the target fragmentation process becomes less chaotic with the increase of average multiplicities of the final states.

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.