Effects of charged Higgs bosons in the deep inelastic process ντN→τ-X and the possibility of detecting tau-neutrinos at cosmic neutrino detectors

We study the deep inelastic process nu(tau) + N- -> tau(-) + 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. We present results which show strong dependence of such contributions on tan beta and MH+/-. We show that for tan beta approximate to 150 and MH+/- approximate to 300 GeV, the contribution of the charged Higgs boson exchange diagrams to the cross-section of the charged current inclusive nu N-tau collision can become important. We find that this contribution for an inclusive dispersion generated through the collision of an ultra-high-energy tau-neutrino with E-nu approximate to 10(21) eV on a target nucleon can be as large as 40% of the value of the contribution of the W exchange diagrams, provided MH+/- approximate to 300 GeV and tan beta approximate to 150. Such enhancement and the induced variation on the mean inelasticity < y >(CC) could lead to sizeable effects in the acceptance of cosmic tau-neutrino detectors at experiments such as HiRes, PAO and the CRTNT, which are anchored to the ground, and at experiments such as EUSO and OWL, which are proposed to orbit around the Earth. We also compare the contribution to sigma(tot)(H+) from the different allowed initial quarks and we show that the contribution from the bottom quark dominates by far. This means that the H+/- contribution practically always gives a top quark in the final state. Such a large component of the cross-section having a top quark event in the final state could have recognizable features in the EAS experiments.