22 research outputs found
Neutron beta decay in effective field theory
Radiative corrections to the lifetime and angular correlation coefficients of
neutron beta-decay are evaluated in effecitive field theory. We also evaluate
the lowest order nucleon recoil corrections, including weak-magnetism. Our
results agree with those of the long-range and model-independent part of
previous calculations. In an effective theory the model-dependent radiative
corrections are replaced by well-defined low-energy constants. The effective
field theory allows a systematic evaluation of higher order corrections to our
results to the extent that the relevant low-energy constants are known.Comment: 13 pages, 1 figure; two references added, minor correctio
Neutral Particles in Light of the Majorana-Ahluwalia Ideas
The first part of this article (Sections I and II) presents oneself an
overview of theory and phenomenology of truly neutral particles based on the
papers of Majorana, Racah, Furry, McLennan and Case. The recent development of
the construct, undertaken by Ahluwalia [{\it Mod. Phys. Lett. A}{\bf 9} (1994)
439; {\it Acta Phys. Polon. B}{\bf 25} (1994) 1267; Preprints LANL
LA-UR-94-1252, LA-UR-94-3118], could be relevant for explanation of the present
experimental situation in neutrino physics and astrophysics.
In Section III the new fundamental wave equations for self/anti-self
conjugate type-II spinors, proposed by Ahluwalia, are re-casted to covariant
form. The connection with the Foldy-Nigam-Bargmann-Wightman- Wigner (FNBWW)
type quantum field theory is found. The possible applications to the problem of
neutrino oscillations are discussed.Comment: REVTEX file. 21pp. No figure
Radiative tritium beta-decay and the neutrino mass
The shape of the electron energy spectrum in 3H beta-decay permits a direct
assay of the absolute scale of the neutrino mass; a highly accurate theoretical
description of the electron energy spectrum is necessary to the empirical task.
We update Sirlin's calculation of the outer radiative correction to nuclear
beta-decay to take into account the non-zero energy resolution of the electron
detector. In previous 3H beta-decay studies the outer radiative corrections
were neglected all together; only Coulomb corrections to the spectrum were
included. This neglect artificially pushes m_nu^2 < 0 in a potentially
significant way. We present a computation of the theoretical spectrum
appropriate to the extraction of the neutrino mass in the sub-eV regime.Comment: 11 pages, 4 eps figures; discussion, figure adde
Evidence for -atoms with DIRAC
We present evidence for the first observation of electromagnetically bound
-pairs (-atoms) with the DIRAC experiment at the CERN-PS.
The -atoms are produced by the 24 GeV/c proton beam in a thin Pt-target
and the and -mesons from the atom dissociation are analyzed in
a two-arm magnetic spectrometer. The observed enhancement at low relative
momentum corresponds to the production of 173 54 -atoms. The mean
life of -atoms is related to the s-wave -scattering lengths, the
measurement of which is the goal of the experiment. From these first data we
derive a lower limit for the mean life of 0.8 fs at 90% confidence level.Comment: 15 pages, 9 figure