Improvement of low energy atmospheric neutrino flux calculation using   the JAM nuclear interaction model
  We present the calculation of the atmospheric neutrino fluxes with an interaction model named JAM, which is used in PHITS (Particle and Heavy-Ion Transport code System). The JAM interaction model agrees with the HARP experiment a little better than DPMJET-III. After some modifications, it reproduces the muon flux below 1~GeV/c at balloon altitudes better than the modified-DPMJET-III which we used for the calculation of atmospheric neutrino flux in previous works. Some improvements in the calculation of atmospheric neutrino flux are also reported. 
Morihiro Honda, Takaaki Kajita, Katsuaki Kasahara, and Shoichi   Midorikawa
astro-ph.HE