Effects of charged Higgs bosons in the ντN deep inelastic scattering within the 2HDM(II) and the UHE ντ detection

We study the deep inelastic process ντ + N → τ- + X (with N ≡ (n + p)/2 an isoscalar nucleon), in the context of the two Higgs doublet model type II (2HDM(II)). We discuss the contribution to the total cross section of diagrams, in which a charged Higgs boson is exchanged. The results show the strong dependence of such contribution on tan β and MH±. In the region 50 ≤ tan β ≤ 200 and 90 GeV ≤ MH± ≤ 600 GeV with the additional experimental constraint on the involved model parameters MH± ≥ 1.5 x tan β GeV, the contribution of the charged Higgs boson exchange diagrams to the cross section of the charged current inclusive ντN collision can become important. The contribution for an inclusive dispersion generated through the collision of an ultrahigh energy tau-neutrino with Eν ≅ 1020 eV on a target nucleon can be larger than the value of the contribution of the W± exchange diagrams, provided that MH± ≅ 300 GeV and tan β ≅ 200. Such enhancement and the induced variation on the mean inelasticity CC could lead to sizeable effects in the acceptance of cosmic tau-neutrino detectors