Atmospheric neutrino flux calculation using the NRLMSISE-00 atmospheric model

Abstract

In this paper, we extend the calculation of the atmospheric neutrino flux~\cite{hkkm2004,hkkms2006,hkkm2011} to the sites in polar and tropical regions. In our earliest full 3D-calculation~\cite{hkkm2004}, we used DPMJET-III~\cite{dpm} for the hadronic interaction model above 5~GeV, and NUCRIN~\cite{nucrin} below 5~GeV. We modified DPMJET-III as in Ref.~\cite{hkkms2006} to reproduce the experimental muon spectra better, mainly using the data observed by BESS group~\cite{BESSTeVpHemu}. In a recent work~\cite{hkkm2011}, we introduced JAM interaction model for the low energy hadronic interactions. JAM is a nuclear interaction model developed with PHITS (Particle and Heavy-Ion Transport code System)~\cite{phits}. In Ref.~\cite{hkkm2011}, we could reproduce the observed muon flux at the low energies at balloon altitude with DPMJET-III above 32 GeV and JAM below that better than the combination of DPMJET-III above 5~GeV and NUCRIN below that. Besides the interaction model, we have also improved the calculation scheme according to the increase of available computational power, such as the "virtual detector correction" introduced in Ref.~\cite{hkkms2006} and the optimization of it in Ref.~\cite{hkkm2011}. The statistics of the Monte Carlo simulation is also improved at every step of the work.