116971806
Problems in electromagnetic mass-difference calculations.
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.
121251309
SOME QUARK--PARTON-MODEL INEQUALITIES FOR THE NEUTRON AND PROTON INELASTIC STRUCTURE FUNCTIONS.
120289082
NOTE ON THE MOST PROBABLE NUMBER OF PARTONS IN PARTON MODELS.
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.
120652883
Model for the leading light-cone singularity of the current commutator
117852266
Investigating Possible Neutrino Decay in Long Baseline Experiment Using ICAL as Far end Detector
We investigate the effects of possible decay of neutrinos from a neutrino factory in a long baseline experiment. We consider the neutrinos from a factory at CERN and the detector to be the 50 kTon iron calorimeter (ICAL) detector proposed for India-based Neutrino Observatory (INO). We found considerable depletion of muon yield at INO for certain value of decay parameters.
126402826
Extension of Minimal Fermionic Dark Matter Model
18903505
DARK MATTER CANDIDATE IN A HEAVY HIGGS MODEL: DIRECT DETECTION RATES
We investigate direct detection rates for Dark Matter candidates arise in a SU(2)L×U(1)Y with an additional doublet Higgs proposed by Barbieri, Hall and Rychkov. We refer to this model as "Heavy Higgs Model". The Standard Model Higgs mass comes out from this model is very heavy, so there is very slim chance that there is no Higgs boson mass below 200 GeV. The additional Higgs boson develops neither any VEV due to the choice of coefficient of the scalar potential of the model nor it has any coupling with fermions due to the incorporation of a discrete parity symmetry. Thus, the neutral components of the extra doublet are stable and can be considered as probable candidate of Cold Dark Matter. We have made calculations for three different types of Dark Matter experiments, namely, 76Ge (like GENIUS), DAMA (NaI) and XENON (131Xe). Also demonstrated the annual variation of Dark Matter detection in case of all three
118940895
"Bimaximal + Democratic"type neutrino mass matrix in view of quark-lepton complementarity
We demonstrate that `Bimaximal + Democratic' type neutrino mass matrix can accommodate the deviation of $\theta_\odot$ from its maximal value which referred in the literature as `quark-lepton complementarity' along with the other present day neutrino experimental results, namely, atmospheric, CHOOZ, neutrinoless double beta decay ($\beta\beta_{0\nu}$) and result obtained from WMAP experiment. We define a function $\chi_p$ in terms of solar and atmospheric neutrino mass squared differences and solar neutrino mixing angle (obtained from different experiments and our proposed texture). The masses and mixing angles are expressed in terms of three parameters in our proposed texture. The allowed region of the texture parameters is obtained through minimization of the above function. The proposed texture crucially depends on the value of the experimental results of $\beta\beta_{0\nu}$ experiment among all other above mentioned experiments. If, in future, $\beta\beta_{0\nu}$ experiments, namely, MOON, EXO, GENIUS shift the lower bound on $$ at the higher side by one order, the present texture will be ruled out.
2568474
Late-time acceleration in a slow-moving Galileon field
�� 2M2 � ;� � ;� respects the Galileon symmetry in curved spacetime. We carry out detailed investigations of the underlying dynamics of this Lagrangian with an Einstein-Hilbert term and a potential. We demonstrate that the model can give rise to a viable ghost-free late-time acceleration of the universe. Furthermore, we study the cosmological perturbation of the model and see that the model gives different big bang nucleosynthesis constraints at early times. We also carry out the observational analysis of the model and use observational data from growth, type Ia supernovae data, baryon acoustic oscillations, and the cosmic microwave background to constrain the parameters of the theory. From cosmological observations (1-4) it is evident that our Universe is currently undergoing an accelerated ex- pansion. The theoretical understanding of the nature of cosmic repulsion is a challenge for the cosmologist and the particle physicist today. A variety of approaches have been studied to address this problem, but to date there is still no definite answer. According to the standard ap- proach, the late-time acceleration can be accounted for by supplementing the energy-momentum tensor by an exotic fluid component with large negative pressure dubbed dark energy (5-12), which constitutes about three quarters of the total cosmic budget of the Universe (13). The simplest candidate for dark energy which is consistent with the observations is provided by a cosmological con- stant � . However, there are various serious theoretical problems associated to it, namely, the fine-tuning and the coincidence problems. An interesting alternative to a cosmological constant is provided by the scalar fields. The cosmological dynamics of a variety of scalar field models has been studied in the literature (7). Though these models do not address the cosmological constant problem, they can give late-time cosmic acceleration and can also provide a viable cosmo- logical dynamics at early epochs. Scalar field models with generic features like the trackers are capable of alleviating the fine-tuning and coincidence problems. At present, these scalar field models are absolutely consistent with the observations but, at the same time, a large number of these models are also permitted. One must therefore rely on future data which should allow one to narrow down the class of permissible scalar field dark energy models.