Search results for "CAPTURE"
showing 10 items of 463 documents
Monochromatic neutrino beams
2005
In the last few years spectacular results have been achieved with the demonstration of non vanishing neutrino masses and flavour mixing. The ultimate goal is the understanding of the origin of these properties from new physics. In this road, the last unknown mixing [U-e3] must be determined. If it is proved to be non-zero, the possibility is open for Charge Conjugation-Parity (CP) violation in the lepton sector. This will require precision experiments with a very intense neutrino source. Here a novel method to create a monochromatic neutrino beam, an old dream for neutrino physics, is proposed based on the recent discovery of nuclei that decay fast through electron capture. Such nuclei will…
Configuration mixing and total muon capture rates
1973
Abstract We modify the Primakoff closure approximation to get independence on the mean neutrino energy and energy weighted sum rules are used for the corrective terms. A near model - independent discussion is then possible, and the total rates are shown to be a very sensitive tool to investigate configuration mixing of the target. Wild discrepancies with experiment would arise if the limit of pure jj or LS couplings are used for 12 C, whereas the Cohen-Kurath wave function gives a very good result.
SU(4) breaking, allowed transitions and total muon capture rates in nuclei
1973
The authors study muon capture rates in light nuclei and show that one can evaluate them in a model-independent way by correcting the Primakoff closure approximation to the first order in the neutrino energy dependence. In this framework the interplay between the existence of allowed transitions and SU(4) breaking is analyzed. In the correction to the first order in the neutrino energy dependence by a sum rule, Majorana and SU(4) breaking potentials are taken into account. The method is also applied to single multipolar transitions, in particular for the dipole transitions. General considerations are illustrated for /sup 6/Li and /sup 12/C by explicit calculations. The stability of the resu…
On total muon capture rates and the average neutrino energy
1973
A method of avoiding the uncertainty associated with the average neutrino energy nu in the usual closure approach to muon capture rates is discussed. Instead of neglecting the kinematic dependence on each particular channel, the partial capture rate is approximated by a first-order expansion around nu . After the sum over the final states is performed, the result is quite independent of the specific value of nu . Application to /sup 3/He, /sup 6/Li and closed-shell nuclei is given, as an effective test of the nuclear models used. (17 refs).
Coherent muon-electron conversion in the dualized standard model
2000
Muon-electron conversion in nuclei is considered in the framework of the Dualized Standard Model. The ratio $B_{\mu-e}$ of the conversion rate to the total muon capture rate is derived, and computed for several nuclei in a parameter-free calculation using parameters previously determined in different physical contexts. The values obtained all lie within the present experimental bounds, but some are so close as to seem readily accessible to experiments already being planned. Similar considerations are applied also to muon-electron conversion in muonium but give rates many orders of magnitude below the present experiment limit.
New supersymmetric quartet of nuclei in the A ∼ 190 mass region
2009
We present evidence for a new supersymmetric quartet in the A=190 region of the nuclear mass table. New experimental information on transfer and neutron capture reactions to the odd-odd nucleaus 194 Ir strongly suggests the existence of a new supersymmetric quartet, consisting of the 192,193 Os and 193,194 Ir nuclei. We make explicit predictions for the odd-neutron nucleus 193 Os, and suggest that its spectroscopic properties be measured in dedicated experiments.
Nuclear effects on lepton polarization in charged-current quasielastic neutrino scattering
2006
We use a correlated local Fermi gas (LFG) model, which accounts also for long distance corrections of the RPA type and final-state interactions, to compute the polarization of the final lepton in charged-current quasielastic neutrino scattering. The present model has been successfully used in recent studies of inclusive neutrino nucleus processes and muon capture. We investigate the relevance of nuclear effects in the particular case of $\tau$ polarization in tau-neutrino induced reactions for several kinematics of relevance for neutrino oscillation experiments.
Neutrinoless double-electron capture
2014
Direct determination of the neutrino mass is at the present time one of the most important aims of experimental and theoretical research in nuclear and particle physics. A possible way of detection is through neutrinoless double-electron capture, $0\ensuremath{\nu}\mathrm{ECEC}$. This process can only occur when the energy of the initial state matches precisely that of the final state. We present here a calculation of prefactors (PFs) and nuclear matrix elements (NMEs) within the framework of the microscopic interacting boson model (IBM-2) for $^{124}\mathrm{Xe}$, $^{152}\mathrm{Gd}$, $^{156}\mathrm{Dy}$, $^{164}\mathrm{Er}$, and $^{180}\mathrm{W}$. From the PF and NME we calculate the expe…
Direct neutrino mass measurements
1995
The paper reports on recent progress and developments since the neutrino '92 conference in the search for finite neutrino masses by direct mass measurements. Regarding the mass of μ - and τ -neutrino experiments have been finished and come up with somewhat improved upper bounds; the negative m 2 -value for the μ -neutrino could be removed mostly. Indications of a 17 keV neutrino component in β -decay spectra have been disproved by a number of alternative experiments as well as by reanalysis of part of the original data. Regarding the electron neutrino mass, measurements by magnetic spectrometers are phasing out in favour of electrostatic filters with magnetic guiding fields. These experimen…
Radiative and non radiative muon capture on the proton in heavy baryon chiral perturbation theory
1998
We have evaluated the amplitude for muon capture by a proton, mu + p --> n + nu, to O(p^3) within the context of heavy baryon chiral perturbation theory (HBChPT) using the new O(p^3) Lagrangian of Ecker and Mojzis (E&M). We obtain expressions for the standard muon capture form factors and determine three of the coefficients of the E&M Lagrangian, namely, b_7, b_{19}, and b_{23}. We describe progress on the next step, a calculation of the radiative muon capture process, mu + p --> n + nu + gamma.