arXiv subjects

P. Stockinger

Publications and source records attributed to P. Stockinger.

6 recordsLinked to original sources

arXiv1999

Field-Theoretical Treatment of Neutrino Oscillations: The Strength of the Canonical Oscillation Formula

We discuss conceptual aspects of neutrino oscillations with the main emphasis on the field-theoretical approach. This approach includes the neutrino source and detector processes and allows to obtain the neutrino transition or survival probabilities as cross sections derived from the Feynman diagram of the combined source - detection process. In this context, the neutrinos which are supposed to oscillate appear as propagators of the neutrino mass eigenfields, connecting the source and detection processes. We consider also the question why the canonical neutrino oscillation formula is so robust against corrections and discuss the nature of the oscillating neutrino state emerging in the field-theoretical approach.

hep-ph↗

arXiv1999

Field-theoretical treatment of neutrino oscillations

We discuss the field-theoretical approach to neutrino oscillations. This approach includes the neutrino source and detector processes and allows to obtain the neutrino transition or survival probabilities as cross sections derived from the Feynman diagram of the combined source -- detection process. In this context, the neutrinos which are supposed to oscillate appear as propagators of the neutrino mass eigenfields, connecting the source and detection processes.

hep-ph↗

arXiv1999

Electron and Neutron Electric Dipole Moments in the Constrained MSSM

We analyze the effects of CP-violating phases on the electric dipole moment (EDM) of electron and neutron in the constrained minimal supersymmetric model. We find that the phases phi_μ and phi_{A_0} have to be strongly correlated, in particular for small values of the SUSY mass parameters. We calculate the neutron EDM in two different models, the Quark-Parton Model and the Chiral Quark Model. It turns out that the predictions are quite sensitive to the model used. We show parameter regions in the M_0-M_1/2 plane which are excluded by considering simultaneously the experimental bounds of both electron and neutron EDM, assuming specific values for the phases phi_μ and phi_{A_0}.

hep-ph↗

arXiv1998

The field-theoretical approach to coherence in neutrino oscillations

We study the conditions for the existence of neutrino oscillations in the field-theoretical approach which combines neutrino production and detection processes in a single Feynman graph. The ``oscillating neutrino'' is represented by an inner line of this graph where, due to the macroscopic distance L between source and detector, the neutrino propagators for neutrinos with definite mass are replaced by the projection operators unto the neutrino states on mass shell. We use as a concrete model reaction the neutrino source and detector as given in the LSND experiment and we carefully take into account the finite lifetime of the stopped muons which provide the anti-muon neutrino beam. We show that the field-theoretical approach provides a solid method to locate all possible conditions and allows to separate unambiguously their different origins. Some of these conditions are independent of L whereas others state that coherence is lost when L exceeds a certain ``coherence length''. Also it turns out that, at least in the concrete situation considered here, the concept of neutrino wave packets is not supported by the field-theoretical approach for realistic experimental conditions, i.e., the neutrino energy spread is incoherent in origin.

hep-ph↗

arXiv1997

Effects of neutrino oscillations and neutrino magnetic moments on elastic neutrino-electron scattering

We consider elastic antineutrino-electron scattering taking into account possible effects of neutrino masses and mixing and of neutrino magnetic moments and electric dipole moments. Having in mind antineutrinos produced in a nuclear reactor we compute, in particular, the weak-electromagnetic interference terms which are linear in the magnetic (electric dipole) moments and also in the neutrino masses. We show that these terms are, however, suppressed compared to the pure weak and electromagnetic cross section. We also comment upon the possibility of using the electromagnetic cross section to investigate neutrino oscillations.

hep-ph↗

arXiv1996

Real Oscillations of Virtual Neutrinos

We study the conditions for neutrino oscillations in a field theoretical approach by taking into account that only the neutrino production and detection processes, which are localized in space around the coordinates $\vec{x}_P$ and $\vec{x}_D$, respectively, can be manipulated. In this sense the neutrinos whose oscillations are investigated appear as virtual lines connecting production with detection in the total Feynman graph and all neutrino fields or states to be found in the discussion are mass eigenfields or eigenstates. We perform a thorough examination of the integral over the spatial components of the inner neutrino momentum and show that in the asymptotic limit $L=|\vec{x}_D - \vec{x}_P| \rightarrow \infty$ the virtual neutrinos become ``real'' and under certain conditions the usual picture of neutrino oscillations emerges without ambiguities.

hep-ph↗