17135383
Lepton Flavour Violating Heavy Higgs Decays Within the nuMSSM and Their Detection at the LHC
Within the ?MSSM, a Minimal Supersymmetric neutrino See-saw Model, Lepton Flavour Violating Higgs couplings are strongly enhanced at large tan? (?30), which can lead to BR(H0/A0???)?O(10?4), for MH0/A0?160 GeV. Enhancements on the production of Higgs bosons, through the gluon fusion mechanism, gg?H0/A0gg?H0/A0, and the associated production channel gg,qq¯?bb¯H0/A0, whose rates grow with tan?, as well as the mass degeneracy that occurs between the H0 and A0 states in this regime, also contribute to further the possibilities to detect a heavy Higgs signal into ?? pairs. We show that the separation of ?? Higgs events from the background at the upcoming CERN Large Hadron Collider could be done for Higgs masses up to about 600 GeV for 300 fb?1 of luminosity, for large tan? values. However, even with as little as 10 fb?1 one can probe H0/A0 masses up to 400 GeV or so, if tan?=60. Altogether, these processes then provide a new Higgs discovery mode as well as an independent test of flavour physics.
17303620
Study of single sneutrino production in association with fermion pairs at polarized photon colliders
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.
17801288
Signals for gauge mediated supersymmetry breaking model at an e−e− collider
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.
15752198
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.
121486698
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.
6337992
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.
115390730
MAXIMUM PSEUDORAPIDITY GAP ANALYSIS IN NUCLEAR INTERACTIONS FROM A FEW GeV TO FEW HUNDRED GeV
This paper presents new results on the maximum gap (∆max) in the pseudorapidity distribution of charged particles in individual events in Mg-AgBr, O-AgBr and S-AgBr interaction in the energy range 4.5− 200 AGeV. The location of the ∆max in an event and the experimental ∆max distribution at all energies has been studied in details. It has been observed that Gaussian distribution can describe the experimental data satisfactorily over the entire energy range.
122027321
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.
123012389
Multiplicity fluctuations of pions and protons at SPS energy — An in-depth analysis with factorial correlator
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.
122688628
Multifractal detrended fluctuation analysis of pseudorapidity and azimuthal distribution of pions emitted in high energy nuclear collisions
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.
122148702
Characteristics of multiplicity distribution of target fragments in forward and backward hemispheres in high-energy nucleus–nucleus interactions
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.