Working group report: Low energy and flavour physics
This is a report of the low energy and flavour physics working group at WHEPP-8, held at the Indian Institute of Technology, Mumbai, India, during 5–16 January 2004.

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: 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: 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: 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: 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: 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: Evidence of scaling of void probability in nucleus-nucleus interactions at few GeV energy
abstract: The rapidity gap probability in the ${}^{24}\mathrm{M}\mathrm{g}\ensuremath{-}\mathrm{A}\mathrm{g}\mathrm{B}\mathrm{r}$ interaction at $4.5\mathrm{GeV}/c/\mathrm{nucleon}$ has been studied in detail. The data reveal scaling behavior of the void probability in the central rapidity domain which confirms the validity of the linked-pair approximation for the $N$-particle cumulant correlation functions. This scaling behavior appears to be similar to the void probability in the Perseus-Pisces supercluster region of galaxies.

title: Multidimensional intermittency study of target fragments at CERN SPS energies
abstract: An investigation on the presence of ring and jet-like structures is carried out in the angular emission of target-evaporated slow particles emitted in 16 O–Ag/Br interactions at 60 A GeV/c and 32 S–Ag/Br interactions at 200 A GeV/c. The nuclear emulsion technique was employed to collect the experimental data. We compared our experimental results with those obtained from Monte Carlo simulations. The analysis indicates the presence of ring and jet-like structures in the experimental data beyond the statistical noise. The presence of ring-like structure is fairly pronounced in 16 O–Ag/Br interactions compared to 32 S–Ag/Br interactions and jet-like structure is more distinct in 32 S. One dimensional (1d) intermittency for ring-like structures and two dimensional (2d) intermittency for jet-like structures are expected. The self-affine behavior of 2d scaled factorial moments (SFM) were investigated and the strength of 2d intermittency was determined. For each set of data, the 2d results were compared with the corresponding one-dimensional (1d) intermittency results. The strength in 2d is significantly greater than 1d for 32 S–Ag/Br interactions whereas for 16 O–Ag/Br interactions 1d is greater than 2d. This is also a sign of predominance of jets in 32 S–Ag/Br and the rings in 16 O–Ag/Br interactions.

title: Multifractal behavior of nuclear fragments in high-energy leptonic interactions
abstract: The multifractal analysis of nuclear fragmentation data obtained from muon-nucleus interactions at 420{+-}45 GeV is performed using G-moment and Takagi-moment methods. The generalized fractal dimensions D{sub q} are determined from these methods and also are compared with those obtained from intermittency exponents. The analysis reveals the multifractal behavior of target fragments in lepton-nucleus interactions.

title: MAXIMUM PSEUDORAPIDITY GAP ANALYSIS IN NUCLEAR INTERACTIONS FROM A FEW GeV TO FEW HUNDRED GeV
abstract: 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.