In this paper we estimate the flux of PeV neutrinos and gamma-rays from magnetar polar caps, assuming that ions/protons are injected, and accelerated in these regions and interact with the radiative background. The present study takes into account the effect of the photon splitting mechanisms that should modify the radiative background, and enhance the neutrino and gamma-ray fluxes at PeV energies, with a view to explain the PeV neutrino events detected in IceCube. The results indicate that in near future, possibility of any significant excess of neutrino events from a magnetar in Milky Way is extremely low. Further, we suggest that the simultaneous observation of neutrinos and gamma-rays at Earth from expanded 'Gen2' IceCube detector and/or High Altitude Water Cherenkov Observatory would provide opportunities to explore the possible origin of very high energy neutrinos and gamma-rays.

Analyzing simulated extensive air shower (EAS) events generated with the Monte Carlo code CORSIKA, this paper critically studies the characteristics of lateral distribution of electrons in EAS around the knee energy region of the energy spectrum of primary cosmic rays. The study takes into account the issue of lateral shower age parameter as indicator of the stage of development of showers in the atmosphere. The correlation of lateral shower age parameter with other EAS observables is examined, using simulated data in the context of its possible use in a multi-parameter study of EAS, with a view to obtaining information about the nature of the shower initiating primaries at sea level EAS experiments. It is shown that the observed slope of the lateral density function in the 3-dimensional plot at least for the KASCADE data supports the idea of a transition from light to heavy mass composition around the knee.PACS numbers: 96.50.sd, 95.75.z, 96.50.S

A Monte Carlo (MC) simulation study of cosmic ray (CR) extensive air showers (EAS) has been carried out in the energy regime of the KASCADE experiment. From the characteristics of lateral distributions of electrons and muons of simulated EAS, some important EAS observables are extracted by a novel approach, and their CR mass-sensitivity is demonstrated. The study takes into account the issue of the experimental lateral density profiles of EAS electrons and muons after introducing the notion of the local age and segmented slope parameters, aimed to extract information on CR mass composition from observed data. The estimated lateral shower age and slope from the analysis of the KASCADE data (KCDC) agrees with the idea of a gradual change of CR mass composition from light to heavy around the knee.PACS numbers: 96.50.sd, 95.75.z, 96.50.S

The effect of the geomagnetic Lorentz force on the muon component of extensive air shower (EAS) has been studied in a Monte Carlo generated simulated data sample. This geomagnetic field affects the paths of muons in an EAS, causing a local contrast or polar asymmetry in the abundance of positive and negative muons about the shower axis. The asymmetry can be approximately expressed as a function of transverse separation between the positive and negative muons barycentric positions in the EAS through opposite quadrants across the shower core in the shower front plane. In the present study, it is found that the transverse muon barycenter separation and its maximum value obtained from the polar variation of the parameter are higher for Iron primaries than protons for highly inclined showers. Hence, in principle, these parameters can be exploited to the measurement of primary cosmic-ray chemical composition. Possibility of practical realization of the proposed method in a real experiment is briefly discussed.PACS numbers: 98.70. Sa, 96.50.sd,

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