123418762
Maximum fluctuations of charged particle densities in narrow pseudorapidity space at ultrarelativistic nuclear collisions
A study of multiparticle correlations on the basis of the maximum fluctuation of the charged particle density in narrow pseudorapidity intervals in Monte Carlo background particles has been carried out with ${}^{16}\mathrm{O}\ensuremath{-}\mathrm{A}\mathrm{g}\mathrm{B}\mathrm{r}$ interactions at $60A\mathrm{GeV}$ and ${}^{32}\mathrm{S}\ensuremath{-}\mathrm{A}\mathrm{g}\mathrm{B}\mathrm{r}$ interactions at $200A\mathrm{GeV}.$ The study reveals the existence of dynamical multipion correlation in the pseudorapidity interval 0.1\char21{}1 for both data sets. Further study suggests that in each case the maximum charged particle density in a given pseudorapidity interval increases linearly with charged particle multiplicity.
120905653
NON-STATISTICAL FLUCTUATIONS OF PIONS FOR RING- AND JET-LIKE EVENTS AT CERN SPS ENERGY — AN IN-DEPTH ANALYSIS WITH FACTORIAL CORRELATOR
This study reveals the analysis of ring-like and jet-like events in terms of factorial correlations of 16O–Ag/Br interactions at 60A GeV. The investigation revealed that the correlated moments are found to increase with decreasing bin–bin separation D and follows a power-law which suggests the presence of an intermittent nature of self-similar dynamical fluctuations pattern for ring-like and jet-like events. From the analysis we find that for jet-like events the strength of non-statistical fluctuation is greater than the ring-like and total event set. Jet-like events follow the bin size independence according to α model of intermittency as like total events, whereas ring-like events are not consistent with the prediction of α model of intermittency.
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.
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.
122068137
MULTIPLICITY DISTRIBUTION AND MULTIPLICITY MOMENT OF BLACK AND GREY PARTICLES IN HIGH ENERGY NUCLEUS–NUCLEUS INTERACTIONS
In this paper we have studied the multiplicity distribution of black and grey particles emitted from 16O–AgBr interactions at 2.1 AGeV and 60 AGeV. We have also calculated the multiplicity moment up to the fifth order for both the interactions and for both kinds of emitted particles. The variation of multiplicity moment with the order number has been investigated. It is seen that in the case of black particles multiplicity moment up to fourth order remains almost constant as energy increases from 2.1 AGeV to 60 AGeV. Fifth order multiplicity moment increases insignificantly with energy. However in the case of grey particles no such constancy of multiplicity moment with energy of the projectile beam is obtained. Later we have extended our study on the basis of Regge–Mueller approach to find the existence of second order correlation during the emission of black as well as the grey particles. The second Mueller moment is found to be positive and it increases as energy increases in the case of black particles. On the contrary in the case of grey particles the second Mueller moment decreases with energy. It can be concluded that as energy increases correlation among the black particles increases. On the other hand with the increase of energy correlation among the grey particles is found to diminish.
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.
119215781
Probing the light Higgs pole resonance annihilation of dark matter in the light of XENON100 and CDMS-II observations
We consider the prospect of lightest neutralino (χ 0 1 ) as a dark matter candidate in light of recent interesting observations from the XENON100 and CDMS-II experiments in minimal supergravity framework with large tanβ and nonvanishing A 0 . Within the WMAP satisfied zone, there is a large direct detection reach of lighter χ 0 1 in the lighter Higgs boson mediated resonance annihilation domain of the above scenario. It is seen that the heavier Higgs boson plays a dominating role in the χ 0 1 - p cross section in the associated zone of parameter space in spite of having a larger mass. Possible LHC signatures are discussed.
119003667
CP violating SUSY effects in Penguin dominated modes B -> PHI K and B -> PHI K*
Recent measurement of time dependent asymmetries in $B \to \phi K$ are indicative of a new source of CP violation. We examine squark mixing in SUSY as this new source, and using QCD improved factorization method to describe $B \to \phi K $ decay, find the allowed range of parameter space for $\rho$ and $\psi $, the magnitude and phase of the down type LR(RL) squark mixing parameter $\delta^{bs}_{LR(RL)}$. We then study $B \to \phi K^{*}$ and calculate the expected CP asymmetries in the same range of parameter space. We find that this asymmetry is in the range 15% to $20% $ for acceptable value of $B \to phi K^{*}$ branching ratio. We also predict the helicity dependent CP asymmetries in the same parameter space.
119244246
Four lepton flavor violating signals at the LHC
A bstractSome yet unknown dynamics is expected to be at work behind the flavor puzzles of the Standard Model. Speculations exist that this may manifest itself in significant strength at the terascale. One consequence may be lepton flavor violation with total lepton number conserved. Already observed in neutrino oscillation experiments, such a phenomenon may show up more prominently at TeV energies, thus signaling a completely new physics. Proposed flavor violating charged dilepton states have already been studied with reference to the LHC. Here we study the production and detection at the LHC of flavor violating charged quadrileptons which are shown to have certain advantages over dileptons in searching for lepton flavor violation. A classification of all six-fermionic operators, in the chiral basis and contributing to such processes, is made and the corresponding cross section for each in 14 TeV pp collisions is computed under the hypothesis of single operator dominance. We further present the sensitivity reach of the new physics scale Λ in terms of the integrated luminosity £.
50826322
LHC signals of T-odd heavy quarks in the Littlest Higgs model
Recently proposed Little Higgs models present a viable solution to the naturalness problem of the Standard Model. An additional discrete symmetry, called T-parity, has been included in the simplest Little Higgs models to evade the constraints arising from electroweak precision data. The Littlest Higgs model with T-parity (LHT) not only predicts a set of new fermions in addition to the heavy gauge bosons of the original Little Higgs model, but also provides a new candidate for dark matter. In this paper, we study two particularly interesting signatures of T-odd fermion pair production at the LHC, namely, (a) jj+l+l−+ and (b) jj+b+l±+. Using a parton level Monte Carlo event generator, we evaluate both the signal as well as the standard model background profile for a selected set of model parameters thereby developing a good discriminator. Finally, we scan the parameter space and delineate the possible discovery region in the same.
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