arXiv subjects

M. Beuthe

Publications and source records attributed to M. Beuthe.

3 recordsLinked to original sources

arXiv2002

Towards a unique formula for neutrino oscillations in vacuum

We show that all correct results obtained by applying quantum field theory to neutrino oscillations can be understood in terms of a single oscillation formula. In particular, the model proposed by Grimus and Stockinger is shown to be a subcase of the model proposed by Giunti, Kim and Lee, while the new oscillation formulas proposed by Ioannisian and Pilaftsis and by Shtanov are disproved. We derive an oscillation formula without making any relativistic assumption and taking into account the dispersion, so that the result is valid for both neutrinos and mesons. This unification gives a stronger phenomenological basis to the neutrino oscillation formula. We also prove that the coherence length can be increased without bound by more accurate energy measurements. Finally, we insist on the wave packet interpretation of the quantum field treatments of oscillations.

hep-ph↗

arXiv1997

Field theory approach to K0-K0bar and B0-B0bar systems

Quantum field theory provides a consistent framework to deal with unstable particles. We present here an approach based on field theory to describe the production and decay of unstable $K^0-\bar{K^0}$ and $B^0-\bar{B^0}$ mixed systems. The formalism is applied to compute the time evolution amplitudes of $K^0$ and $\bar{K^0}$ studied in DAPHNE and CPLEAR experiments. We also introduce a new set of parameters that describe CP violation in $ K \to ππ$ decays without recourse to isospin decomposition of the decay amplitudes.

hep-ph↗

arXiv1996

Behaviour of the Absorptive Part of the W Electromagnetic Vertex

The absorptive part of the $WWγ$ vertex induced by massive fermion loops is considered for different kinematical configurations. We show that the axial part of this vertex is different from zero not only when massive fermions are involved but also for massless fermion loops, if one of the W bosons is space-like and the other is time-like. We also discuss in what sense Low's soft photon theorem is satisfied.

hep-ph↗