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.
123551661
Entropy scaling in high-energy nucleus–nucleus interactions
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.
123263357
Characteristics of pion production in ring-like events using entropy index
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.
119465238
Multidimensional void fluctuation: A search for quark–hadron phase transition
Abstract The event-by-event fluctuation of hadronic patterns is investigated by finding a measure of the nonhadronic regions, the voids, for the experimental data of 32 S–AgBr interactions at 200 A GeV. Two lowest moments of the event-to-event fluctuation of voids, 〈 G q 〉 and S q have been defined by R.C. Hwa and Q.H. Zhang to quantify the dependence of the voids on the bin sizes. Characteristic of the quark–hadron phase transition, if any can be efficiently extracted from the scaling behavior of the voids. The experimental data of π − -AgBr interactions at 350 GeV/c are also probed with the same tool to have a complete view. The results have been compared with the results of the VENUS generated data for the above interactions.
118199521
Evidence of different reaction mechanisms for hot and cold events in relativistic heavy-ion interaction
This paper reports evidence of different reaction mechanisms for two classes of events, ''hot,'' and ''cold,'' in /sup 12/C emulsion at 4.5 (GeV/c)/N observed by Ghosh et al., from a comparison of the transverse-momentum (P/sub T/) distribution with a mixture of two Maxwell-Boltzmann distributions with different temperatures. The hypothesis is substantiated by the significant difference, for ''hot'' and ''cold'' events, in the values of the average number of pions produced, average emission angle of ..cap alpha..-projectile fragments, and ratio of yield of ..cap alpha.. particles to protons as projectile fragments.
119920249
FLUCTUATION PATTERN OF SHOWER AND COMPOUND MULTIPLICITY DISTRIBUTIONS IN NUCLEUS–NUCLEUS INTERACTIONS AT A FEW GeV
This work presents a study on the multiplicity distribution of shower and compound multiplicity (pions + target protons) emitted from 12C–AgBr and 24Mg–AgBr interactions at 4.5 AGeV in terms of negative binomial distribution (NBD) and also on the fluctuation pattern of shower and compound multiplicity in the frame work of two-dimensional factorial moment methodology using the concept of Hurst exponent.
13886879
Constraints on supersymmetric flavor changing parameters using B ---> PP decays
We study contributions of quark-squark-gluino interactions in Minimal Supersymmetric Standard Model (MSSM) to B->PP (PP =Kpi, pipi, KK) decays using QCD improved factorization method for the evaluation of the hadronic matrix elements and taking into account renormalization group running of the Wilson coefficients from SUSY scale (~ m_{\tilde q}) to the low energy scale (= m_b) applicable to B decays. Using the most recent experimental data we obtain constraints on flavor changing Supersymmetric (SUSY) parameters (\delta_{ij})_{LL, RR}. For \Delta S = -1 processes, b-> s gamma is usually considered to give the strongest limits. We, however, find that in some part of the parameter space B-> Kpi processes give stronger bounds. Implications for B^0_s -\bar B^0_s mixing is discussed. We also study cons traints obtained from \Delta S = 0 processes B-> pipi, KK, rho gamma and B_d -\bar B_d mixing. In this case, in a large part of the parameter space B_d - \bar B_d provides the best bound, but B-> K^- K^0, rho gamma can still give interesting constraints in a complementary region of the parameter space.
119203692
B decay anomalies in an effective theory
We investigate how far a new physics scenario affecting primarily the third-generation fermions can ameliorate the tension between $B$ decay observables and Standard Model expectations. Adopting a model-independent approach, we find that among the three observables that show signs of such a tension, viz., the branching fractions for ${B}^{+}\ensuremath{\rightarrow}\ensuremath{\tau}\ensuremath{\nu}$, ${B}_{d}\ensuremath{\rightarrow}D({D}^{*})\ensuremath{\tau}\ensuremath{\nu}$, and the like-sign dimuon anomaly in neutral $B$ decays, the first two can be explained adequately, while there is only a marginal improvement for the third. As a spin-off, it is shown that one can also accommodate a change in the branching fraction of the Higgs boson to a $\ensuremath{\tau}$ lepton pair from the Standard Model expectation, if such a change is established in future data.
120076410
SIGNALS FOR A GAUGE MEDIATED SUPERSYMMETRY BREAKING MODEL AT A FUTURE e-e- COLLIDER
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.
59023381
Single electron signal from anomaly mediated supersymmetry breaking at a future linear collider
Understanding how Supersymmetry (SUSY) breaks in the real world from a deeper, more fundamental standpoint is a major challenge in theoretical high energy physics today. An interesting recent idea in this direction has been that of Anomaly Mediated SUSY Breaking (AMSB) [1] – [15]. AMSB occurs when, in a higher dimension, one has a Supergravity theory defined on two separated parallel 3-branes (3+1 dimensional subspaces) in a way that the Standard Model (SM) particles are localized on one of these while the SUSY breaking sector is localized on the other. There are no tree-level couplings between these two branes. Gravity propagates in the bulk and the breakdown of SUSY is communicated from the hidden sector to the visible one through the loopinduced super-Weyl anomaly. In the absence of tree-level interactions between the two 3-branes, this is the dominant contribution to the soft SUSY breaking parameters. All the masses (of gauginos and scalars) generated through this mechanism are proportional to the corresponding gauge coupling strengths. In fact, these masses become renormalization group invariant with slepton becoming tachyonic. The latter fact is the most severe problem in the AMSB scenario and there are several proposals in the literature to solve it. We shall focus here on the minimal [1] model of AMSB where the problem of tachyonic sleptons is tackled by adding a universal constant term m 0 to the expressions for squared scalar masses, i.e., m 2 0 contributes equally to the squared masses of all scalars present in the theory. One can now solve the tachyonic slepton problem through a suitably chosen m 0 making all squared slepton masses positive, the scale invariance of the expressions for scalar masses being lost. The evolution of scalar masses governed by the corresponding Renormalization Group Equations (RGEs), starting from a very high energy scale, must therefore be taken into account. However, except for the addition of an extra parameter, this is quite a feasible procedure. This model is characterized by several distinct features with important phenomenological consequences: a rather massive gravitino (∼ a few TeV) and nearly mass-degenerate left and right selectrons and smuons, while the staus split into two distinct mass eigenstates with the τ1 being the lightest charged slepton. Most importantly, the model has gauginomasses proportional to the β-functions of the gauge couplings. The latter lead to the existence of a neutral near-Wino as the Lightest Supersymmetric Particle (LSP) χ 1 and closely mass-degenerate with it a pair of charged near-Winos as the lighter charginos χ± 1 . A tiny mass difference ∆M (< 1 GeV) arises between them from loop corrections and a weak gaugino-higgsino mixing at the tree level. Because of the
1450279
Correlations between sneutrino‐antisneutrino oscillations and signatures at the LHC in anomaly‐mediated supersymmetry breaking
Sneutrino‐antisneutrino oscillation can be observed at the LHC by studying a charge asymmetry of the leptons in the final states. In this talk, we demonstrate this in the context of an anomaly‐mediated supersymmetry breaking model which can give rise to a large oscillation probability. The preferred region of the parameter space is characterized by the presence of a sneutrino next‐to‐lightest supersymmetric particle and a stau lightest supersymmetric particle. We show that the signals studied here have certain correlations with the pattern of the sneutrino oscillation.