121757164
Energy dependence of mean square charged multiplicity in Regge--Mueller formalism
Abstract The energy dependence of the mean square multiplicity is obtained on the basis of a Regge-Mueller analysis, when a pomeron with α p(0) = 1 and subsidiary trajectories with α(0) = 1 2 are present. The expression for 〈 n ( n − 1)〉 is shown to be of the form c 1 (ln s ) 2 + c 2 (ln s ) + c 3 + c 4 (ln s ) 2 /√ s + c 5 ln s /√ s + c 6 /√ s , with the coefficients given in terms of certain well defined integrals over physically measurable quantities. We are unable, with available experimental data on inclusive reations to estimate all these coefficients. However, retaining only the terms that survive as s →∞, we obtain a simple expression for the correlation function f 2 = 〈 n ( n −1)〉 − 〈 n 〉 2 for which a reasonable estimate has been made. The agreement with experiment is good.
120289082
NOTE ON THE MOST PROBABLE NUMBER OF PARTONS IN PARTON MODELS.
120652883
Model for the leading light-cone singularity of the current commutator
121251309
SOME QUARK--PARTON-MODEL INEQUALITIES FOR THE NEUTRON AND PROTON INELASTIC STRUCTURE FUNCTIONS.
120089980
ELECTROMAGNETIC MASS DIFFERENCES.
Abstract In Cottingham's approach to electromagnetic masses ( δm ) one encounters the problem of unknown subtractions in the fixed mass dispersion relations for the virtual Compton scattering amplitude. We avoid this problem and express δm in terms of measurable quantities, assuming knowledge of light-cone singularities of the electro-magnetic current commutator.
119967965
Effect of a transverse momentum distribution in the parton model
The parton model for the inelastic lepton-nucleon scattering is generalized to include a realistic momentum distribution of the partons. In this formalism each parton is given a component of momentum which is orthogonal in a four-vector sense to the nucleon momentum. An approximation scheme is developed to take into account the effect of this orthogonal (transverse) momentum distribution of the partons. It is found to generate an additional scale-invariant contribution to the structure function $\ensuremath{\nu}{W}_{2}(\ensuremath{\nu}, {Q}^{2})$ as well as a non-scale-invariant contribution, as is expected. The scale-invariance-breaking term is found to be a power series in $\frac{{Q}^{2}}{{\ensuremath{\nu}}^{2}}$ and vanishes as $\ensuremath{\nu}$ or ${Q}^{2}$ goes to infinity for a fixed $\ensuremath{\omega}=\frac{2M\ensuremath{\nu}}{{Q}^{2}}$. The effect of the transverse momentum distribution is explicitly displayed and discussed for a few momentum distribution functions. The data on inelastic $e\ensuremath{-}p$ scattering are then analyzed for any significant deviations from scale invariance, and it is concluded that there is evidence for such deviations. On the assumption that the systematic errors in the data are small, we make some fits which display the dependence on ${Q}^{2}$. Finally, an attempt is made to fit the data with the formalism developed in the initial part of the paper. For this purpose use is made of a model for the partons, proposed previously by the authors to explain the data in the approximation that scale invariance is satisfied. Some comments are made on the properties of partons which are necessary to fit the data and on the present status of scale-invariance breaking.
118595488
Generalizing thawing dark energy models: the standard vis-à-vis model independent diagnostics
We propose a two parameter generalization for the dark energy equation of state (EOS) wX for thawing dark energy models which includes PNGB, CPL and Algebraic thawing models as limiting cases and confront our model with the latest observational data namely SNe Ia, OHD, CMB, BOSS data. Our analysis reveals that the phantom type of thawing dark energy is favoured upto 2� confidence level. These results also show that thawing dark e nergy EOS is not unique from observational point of view. Though different thawing dark energy models are not distinguishable from each other from best-fit values (upto 2� C.L.s) of matter density parameter ( 0) and hubble parameter (H0) at present epoch, best-fit plots of linear growth of matter perturbation (f ) and average deceleration parameter (qav); the difference indeed reflects in best-fit variations of thawing dark energy EOS, model-independent geometrical diagnostics like the statefinder pair {r, s} and Om3 parameter. We are thus led to the conclusion that unlike the standard observables ( 0, H0, f , qav), the model-independent pa� � ,
7939522
Status of the neutrino decay solution to the solar neutrino problem
Abstract We re-examine the neutrino decay solution to the solar neutrino problem in the light of the SuperKamiokande (SK) data. For the decay solution the SK spectrum data by its own can provide a fit comparable to the fit obtained from the MSW solution. However when one combines the results from the total rates of the 37 Cl and 71 Ga experiments the fit becomes much poorer.
15935653
Effect of flavour oscillations on the detection of supernova neutrinos
Neutrinos and antineutrinos of all three flavours are emitted during the post-bounce phase of a core-collapse supernova with having average energies more than that of They can be detected by the new earthbound detectors like SNO and Super-Kamiokande which are sensitive to neutrinos of all three flavours. In this letter we consider the effect of flavour oscillations on the neutrino flux and their expected number of events at the detector. We do a three-generation analysis and for the mass and mixing schemes we first consider the threefold maximal mixing model consistent with the solar and the atmospheric neutrino data and next a scenario with one m2~10-11 eV2 (solar range) and the other m2~10-18 eV2, for which the oscillation length is of the order of the supernova distance. In both these scenarios there are no matter effects in the resultant neutrino spectrum and one is concerned with vacuum oscillations. We find that though neutrino oscillations result in a depletion in the number of e and coming from the supernova, the actual signals at the detectors are appreciable enhanced as the e and energy spectra become harder.
118651848
Reconstructing the equation of state and density parameter for dark energy from combined analysis of recent SNe Ia, OHD and BAO data
We reconstruct the dark energy equation of state by analyzing 5 sets of SNe Iadata along with Baryon Acoustic Oscillation (BAO) and Observational Hubble Data (OHD). A closed form parametrization of the luminosity distance in terms of redshift is assumed for the χ2 analysis of the observational data. A strong dependence of dark energy equation of state on the matter density in the present and earlier epoch is obtained and the lower limit of matter density parameter at an earlier epoch for a flat FRW universe has been predicted. The variation of dark energy density parameter and the matter density parameter are also obtained.
16847898
Mass and Scalar Cross-sections for Neutralino Dark Matter in Anomaly Mediated Supersymmetry Breaking Model
We consider the neutralino to be the lightest supersymmetric particle in the framework of the minimal anomaly mediated supersymmetry breaking (mAMSB) model. We have studied the variation of the neutralino mass with the supersymmetric parameters. Considering these neutralinos to be candidates for weakly interacting massive particles (WIMPs) or cold dark matter, we have calculated the neutralino nucleon scalar cross sections and compared them with the results of the DAMA-NaI neutralino direct detection search. From this study, we observe that the mAMSB model results cannot explain the allowed region in WIMP mass and WIMP–nucleon scalar cross-section space obtained from the annual modulation signature in the DAMA-NaI experiment.