The Glashow resonance in neutrino-photon scattering

Reactions ${\nu_l}\gamma\rightarrow W^+l^-\,(l=e,\mu,\tau)$ near the threshold $\sqrt{s}=m_W+m_l$ are analyzed. Two independent calculations of the corresponding cross sections (straightforward calculations using the Standard Electroweak Lagrangian and calculations in the framework of the parton model) are compared. It is shown that the Standard Electroweak Theory strongly suggests that these reactions proceed via the Glashow resonances. Accordingly, a hypothesis that the on-shell $W$ bosons in the reactions ${\nu_l}\gamma\rightarrow$$W^+l^-$ are the Glashow resonances is put forward. A role of these reactions for testing T symmetry at the IceCube Neutrino Observatory is discussed. A model with T-violating Glashow resonances for description of the distribution of the TeV-PeV neutrino events recently observed by the IceCube Collaboration is presented.Comment: 25 pages, 11 figures. Typos corrected, minor changes, new references added. Accepted for publication in PL

Particle decays in the presence of a neutrino background

Several non-threshold reactions which may be used to detect the cosmic neutrino background are presented. The corresponding cross sections are calculated analytically within the Standard Model. These reactions are sensitive not only to the electron neutrinos but also to the muon and tau neutrinos. Some possibilities of experimental observation of the neutrino background are indicated.Comment: 14 pages, 5 figures. A more detailed discussion on the observability of neutrino capture by muons is adde