121661899
Multifractal behavior of nuclear fragments in high-energy leptonic interactions
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.
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.
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.
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.
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.
118382400
Stop and sbottom search using dileptonic MT2 variable and boosted top technique at the LHC
A bstractThe ATLAS and CMS experiments at the CERN LHC have collected about 25 fb−1 of data each at the end of their 8 TeV run, and ruled out a huge swath of parameter space in the context of Minimally Supersymmetric Standard Model (MSSM). Limits on masses of the gluino $ \left( {\widetilde{g}} \right) $ and the squarks of the first two generations $ \left( {\widetilde{q}} \right) $ have been pushed to above 1 TeV. Light third generation squarks namely stop and sbottom of sub-TeV masses, on the other hand, are still allowed by their direct search limits. Interestingly, the discovery of a Standard Model (SM) higgs boson like particle with a mass of ~ 125 GeV favours a light third generation which is also motivated by naturalness arguments. Decays of stop and sbottom quarks can in general produce a number of distinct final states which necessitate different search strategies in the collider experiments. In this paper we, on the other hand, propose a general search strategy to look for third generation squarks in the final state which contains a top quark in the sample along with two additional hard leptons and substantial missing transverse momentum. We illustrate that a search strategy using the dileptonic MT2, the effective mass meff and jet substructure to reconstruct the hadronic top quark can be very effective to reduce the SM backgrounds. With the proposed search strategy, we estimate that the third generation squarks with masses up to about 900 GeV can be probed at the 14 TeV LHC with 100 fb−1 luminosity. We also interpret our results in two simplified scenarios where we consider the stop (sbottom) pair production followed by their subsequent decay to a top quark and the second lightest neutralino (lightest chargino). In this case also we find that stop (sbottom) mass up to 1 TeV (0.9 TeV) can be discovered at the 14 TeV LHC with 100 fb−1 integrated luminosity.
18210794
Study of R-parity violating supersymmetric signals at an $e^{-} e^{-}$ collider
We study the pair production of right selectrons at a 500 GeV ${e}^{\ensuremath{-}}{e}^{\ensuremath{-}}$ collider followed by their decay into an electron and a lightest neutralino. This lightest neutralino decays into multifermion final states in the presence of R-parity-violating couplings. A detailed analysis of possible signals is performed for some important regions of the parameter space. The signals are essentially free from the standard model backgrounds.
117035226
Implications of the 98 GeV and 125 GeV Higgs scenarios in nondecoupling supersymmetry with updated ATLAS, CMS, and PLANCK data
We discuss both MSSM and NMSSM scenarios in which the lightest Higgs boson with $m_h=98$~GeV is consistent with the small excess ($\sim 2.3 \sigma$) observed at the LEP in $e^+ e^-\rightarrow Zh$, with $h \rightarrow b {\bar b}$ process and the heavier Higgs boson of mass close to 125~GeV as the observed candidate of the SM Higgs like particle at the LHC. We show the allowed regions in the non-decoupling Higgs zone of MSSM parameter space which are consistent with several low energy constraints coming from heavy flavour physics, latest experimental data on Higgs signals and lower limit on superparticle masses from 7~TeV and 8~TeV LHC run. We also implement the constraints from the relic density of the cold dark matter as obtained from the recent PLANCK data. Additionally, we discuss the possibility of observing the light Higgs boson of mass 98~GeV at the 14~TeV LHC run via $pp \rightarrow V h$, with $h \rightarrow b \bar b$ using the technique of jet substructure. Our analysis shows that at 14~TeV LHC run with 300 ${\rm fb}^{-1}$ luminosity the signal efficiency of such a light Higgs boson is at most 2.5$\sigma$. Finally, we make a comment on the prospect of proposed $e^+ e^-$ ILC to discover/exclude this light Higgs boson.
119208787
Dijet signals of the little Higgs model with T-parity
A bstractThe Littest Higgs model with T-parity (LHT), apart from offering a viable solution to the naturalness problem of the Standard Model, also predicts a set of new fermions as well as a candidate for dark matter. We explore the possibility of discovering the heavy T-odd quark QH at the LHC in a final state comprising two hard jets with a large missing transverse momentum. Also discussed is the role of heavy flavor tagging.
15458052
Characteristic wino signals in a linear collider from anomaly mediated supersymmetry breaking
Though the minimal model of anomaly-mediated supersymmetry breaking has been significantly constrained by recent experimental and theoretical work, there are still allowed regions of the parameter space for moderate to large values of $\mathrm{tan}\ensuremath{\beta}.$ We show that these regions will be comprehensively probed in a $\sqrt{s}=1$ TeV ${e}^{+}{e}^{\ensuremath{-}}$ linear collider. Diagnostic signals to this end are studied by zeroing in on a unique and distinct feature of a large class of models in this genre: a neutral W-ino-like lightest supersymmetric particle closely degenerate in mass with a W-ino-like chargino. The pair production processes ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{e}_{L}^{\ifmmode\pm\else\textpm\fi{}}{e}_{L}^{\ensuremath{\mp}},$ ${e}_{R}^{\ifmmode\pm\else\textpm\fi{}}{e}_{R}^{\ensuremath{\mp}},$ ${e}_{L}^{\ifmmode\pm\else\textpm\fi{}}{e}_{R}^{\ensuremath{\mp}},$ $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\nu}}\ensuremath{\nu}\mathrm{\ifmmode \tilde{}\else \~{}\fi{}\ifmmode \bar{}\else \={}\fi{}},$ ${\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\chi}}}_{1}^{0}{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\chi}}}_{2}^{0},$ ${\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\chi}}}_{2}^{0}{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\chi}}}_{2}^{0}$ are all considered at $\sqrt{s}=1$ TeV corresponding to the proposed DESY TEV Energy Superconducting Linear Accelerator linear collider in two natural categories of mass ordering in the sparticle spectra. The signals analyzed comprise multiple combinations of fast charged leptons (any of which can act as the trigger) plus displaced vertices ${X}_{D}$ (any of which can be identified by a heavy ionizing track terminating in the detector) and/or associated soft pions with characteristic momentum distributions.