The Dispersive Approach to Electroweak Processes in the Background Magnetic Field

We propose a new method to compute amplitudes of electroweak processes in the strong background magnetic field, using $\gamma\to e^+e^-$ as an example. We show that the {\it moments} of $\gamma\to e^+e^-$ width are proportional to the derivatives of photon polarization function at the zero energy. Hence, the pair-production width can be easily calculated from the latter by the inverse Mellin transform. The prospects of our approach are commented.Comment: 3 pages, talk presented in DPF2000, Aug. 9-12, Ohio State

On non hadronic origin of high energy neutrinos

Some of the non hadronic interactions, such as the \eta resonance formation in the \gamma \gamma interactions and the muon pair production in the e\gamma interactions, are identified as possible source interactions for generating high energy neutrinos in the cosmos.Comment: 9 pages, 1 figure, talk given at First NCTS Workshop on Astroparticle Physics, 6-9 December, 2001, Kenting, Taiwan (to appear in its proceedings edited by H. Athar, Guey-Lin Lin, and K.-W. Ng

Gauge Independent Effective Potential and the Higgs Mass Bound

We introduce the Vilkovisky-DeWitt formalism for deriving the lower bound of the Higgs boson mass. We illustrate the formalism with a simplified version of the Standard Electroweak Model, where all charged boson fields as well as the bottom-quark field are disregarded. The effective potential obtained in this approach is gauge independent. We derive from the effective potential the mass bound of the Higgs boson. The result is compared to its counterpart obtained from the ordinary effective potential.Comment: 15 pages, Revtex; version to appear in Phys. Rev.

A semi-analytic calculation on the atmospheric tau neutrino flux in the GeV to TeV energy range

We present a semi-analytic calculation on the atmospheric tau neutrino flux in the GeV to TeV energy range. The atmospheric $\nu_{\tau}$ flux is calculated for the entire zenith angle range. This flux is contributed by the oscillations of muon neutrinos coming from the two-body $\pi, K$ decays and the three-body $\mu^{\pm}$ decays, and the intrinsic tau neutrino flux surviving the oscillations. The uncertainties in our calculations are discussed in detail. The implications of our result are also discussed.Comment: Revtex, 30 pages (including 13 figures); paper expanded and title slightly changed, to appear in Astroparticle Physic