88 research outputs found
On the Possibilities of Distinguishing Dirac from Majorana Neutrinos
The problem if existing neutrinos are Dirac or Majorana particles is
considered in a very pedagogical way. After a few historical remarks we recall
the theoretical description of neutral spin 1/2 particles, emphasizing the
difference between chirality and helicity which is important in our discussion.
Next we describe the properties of neutrinos in the cases when their
interactions are given by the standard model and by its extensions (massive
neutrinos, right-handed currents, electromagnetic neutrino interaction,
interaction with scalar particles). Various processes where the different
nature of neutrinos could in principle be visible are reviewed. We clear up
misunderstandings which have appeared in last suggestions how to distinguish
both types of neutrinos.Comment: 38 pages, Latex, epsfig, 10 poscript files Presented at the XXI
Silesian School of Theoretical Physics on "Recent Progress in Theory and
Phenomenology of Fundamental Interactions", Ustron, September 199
Quantization and renormalization of the manifest left-right symmetric model of electroweak interactions
Quantization and renormalization of the left-right symmetric model is the
main purpose of the paper. First the model at tree level with a Higgs sector
containing one bidoublet and two triplets is precisely discussed. Then the
canonical quantization and Faddeev-Popov Lagrangian are carried out ('t Hooft
gauge). The BRST symmetry is discussed. Subsequently the on mass shell
renormalization is performed and, as a test of consistency, the renormalization
of the ZNiNj vertex is analyzed.Comment: 74 pages, 65 Postscript figures, submitted to Annals of Physic
From kaons to neutrinos: quantum mechanics of particle oscillations
The problem of particle oscillation is considered in a pedagogical and
comprehensive way. Examples from K, B and neutrino physics are given.
Conceptual difficulties of the traditional approach to particle oscillation are
discussed. It is shown how the probability current density and the wave packet
treatments of particle oscillations resolve some problems. It is also shown
that only full field theoretical approach is free from conceptual difficulties.
The possibility of oscillation of particles produced together with kaons or
neutrinos is considered in full wave packet quantum mechanics language. Precise
definition of the oscillation of particles which recoil against mixed states is
given. The general amplitude which describes the oscillation of two particles
in the final states is found. Using this EPR-type amplitude the problem of
oscillation of particles recoiling against kaons or neutrinos is resolved. The
relativistic EPR correlations on distances of the order of coherence lengths
are considered.Comment: revtex, epsfig, 4 figures, 28 pages. Presented at the XXXVIII Cracow
School of Theoretical Physics, Zakopane, June 1-10, 1998, to appear in Acta
Phys. Po
Light neutrino propagation in matter without heavy neutrino decoupling
We review the propagation of light neutrinos in matter assuming that their
mixing with heavy neutrinos is close to present experimental limits. The
phenomenological implications of the non-unitarity of the light neutrino mixing
matrix for neutrino oscillations are discussed. In particular we show that the
resonance effect in neutrino propagation in matter persists, but for slightly
modified values of the parameters and with the maximum reduced by a small
amount proportional to the mixing between light and heavy neutrinos squared.Comment: 11 pages, 1 figure, contribution to Stefan Pokorski 60th birthda
The Minimal Extension of the SM and the Neutrino Oscillation Data
We study the simplest Standard Model estension with only one extra
right-handed neutrino. In this case there are two massless and two
massive neutrinos, and in principle both solar and atmospheric
anomalies can be described in two different scenarios, (scheme I)
and (scheme II). However, neither bi-maximal mixing nor the
dark matter problem are explained in this minimal extension. Only scheme II can
accommodate simultaneously maximal mixing for atmospheric neutrinos and the
small mixing angle MSW solution for the solar anomaly. This scenario can be
tested in the BOREXINO experiment.Comment: 9 pages, Presented by J. Gluza at the XXIII School of Theoretical
Physics, Ustron'99, Poland, September 15-22, 199
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