Signatures of noncommutative QED at photon colliders
In this paper we study non-commutative (NC) QED signatures at photon colliders through pair production of charged leptons(l + l ) and charged scalars(H + H ). The NC corrections for the fermion pair production can be easily obtained since NC QED with fermions has been extensively studied in the literature. NC QED with scalars is less studied. To obtain the cross section for H + H productions, we first investigate the structure of NC QED with scalars, and then study the corrections due to the NC geometry to the ordinary QED cross sections. Finally by folding in the photon spectra for a γγ collider with laser back-scattered photons from the e + e machine, we obtain 95% CL lower bound on the NC scale using the above two processes. We find that, with √ s = 0.5, 1.0, and 1.5 TeV and integrated luminosity L = 500(fb 1 ), the NC scale up to 0.7, 1.2, and 1.6 TeV can be probed, respectively, while, for monochromatic photon beams, these numbers become 1.1, 1.7, 2.6 TeV, respectively.

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: 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: Sneutrino-antisneutrino oscillation at the Tevatron
abstract: Sneutrino-antisneutrino oscillation can be a very useful probe to look for signatures of lepton number violation ({Delta}L=2) at the Tevatron. Here, we discuss a scenario where the total decay width of the sneutrino is very small, producing interesting signals at the Tevatron for a mass splitting {Delta}m as small as 10{sup -14} GeV between the sneutrino mass eigenstates.

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: Triplet Higgs boson at hadron colliders
abstract: The novel feature of a Higgs-triplet representation is a nonzero tree-level coupling of H+W −Z, which is absent in all Higgs-doublet models. We study the associated production of a singly-charged Higgs boson of the Higgs-triplet representation with a W or Z boson at hadron colliders, followed by the H+→W+Z decay. We find that the 2l+4j final state gives an interesting level of signal with a negligible background, plus it allows a full mass reconstruction of the charged-Higgs boson. The cover range of the charged-Higgs mass is between 110 and 200 GeV.

title: Ring-Like and Jet-Like Events in Ultra High-Energy Interactions—an Analysis in Terms of Multifractal Parameters
abstract: Ring-like and jet-like events produced in 16O-AgBr interactions at 60 AGeV are analyzed in terms of multifractal G-moment method and factorial moment method in both η space and ϕ space for emitted pions. Further, the Levy indices and multifractal specific heat c have been calculated. The results clearly indicate that μ and c both are different in ring-like and jet-like events depicting different mechanism in the production process.

title: Event-to-Event Fluctuation Analysis for Pions and Protons at SPS Energy
abstract: This study reports a detailed analysis of spatial fluctuations as well as event-to-event fluctuations of compound hadrons (pions + protons) produced in 32S–AgBr interactions at 200 AGeV with a new technique known as erraticity analysis. This analysis is done for both emission-angle and azimuthal-angle phase spaces using gap-moment method. The study provides a strong evidence of erratic behavior of compound hadrons in ultra-relativistic nuclear collisions.

title: Fluctuations of rapidity gaps in nucleus nucleus collisions: Evidence of erraticity
abstract: The fluctuations of the spatial pattern from event to event have been investigated by analyzing the data of multipion production ${\mathrm{in}}^{24}\mathrm{Mg}\ensuremath{-}\mathrm{AgBr}$ interactions ${\mathrm{and}}^{12}\mathrm{C}\ensuremath{-}\mathrm{AgBr}$ interactions at $4.5A\mathrm{GeV}$ and ${}^{16}\mathrm{O}\ensuremath{-}\mathrm{AgBr}$ interactions at $2.1A\mathrm{GeV}$ and $60A\mathrm{GeV}.$ Two entropylike quantities ${S}_{q}$ and ${\ensuremath{\Sigma}}_{q}$ have been estimated from two different moments of rapidity gaps of produced pions. The investigation provides evidence of the erraticity of rapidity gaps of produced pions in relativistic nuclear collisions.

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: 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.