Related papers: Muon capture by oriented nuclei: new possibilities…
The hyperfine effect in muon capture rate is analyzed with taking into account of the second-order terms in 1/M in the non-relativistic Hamiltonian. It is shown that in the situation of the dominance of the squared first-order terms the…
The T-noninvariant transverse polarization of neutrons is considered for muon capture by a 6-Li nucleus with decay into a quasistationary 2+ state of the three particle alpha+n+n continuum. This polarization is orthogonal to the plane…
We report results from shell model studies of muon capture on $^{40}$Ca to low-lying levels of $^{40}$K. We discuss the comparison between calculated capture rates, measured capture rates and analogous transitions in ($e$,$e^{\prime}$)…
We use the random phase approximation to systematically describe the total muon capture rates on all nuclei where they have been measured. We reproduce the experimental values on these nuclei to better than 15% accuracy using the free…
Electron captures on nuclei play an important role in the collapse of stellar core in the stages leading to a type-II supernova. Recent observations of subluminous Type II-P supernovae (e.g. 2005cs, 2003gd, 1999br) were able to rekindle the…
A specific model of parity-conserving lepton substructure is considered. We show that a positive-definite contribution to the muon $(g-2)/2$ at the possible level of about $4\times 10^{-9}$, can be related to a significant increase in the…
The singlet capture rate $\Lambda_S$ for the semileptonic weak process $\mu+p \to n+\nu_\mu$ has been measured in the MuCap experiment. The novel experimental technique is based on stopping muons in an active target, consisting of a time…
The recent TRIUMF experiment for $\mu^- p \to n \nu_{\mu} \gamma$ gave a surprising result that the induced pseudoscalar coupling constant $g_P$ was larger than the value obtained from $\mu^- p \to n \nu_{\mu}$ experiment as much as 44 %.…
The reaction $\bar{\nu}_e + p \to e^+ + n$ is very important for low-energy ($E_\nu \lesssim 60$ MeV) antineutrino experiments. In this paper we calculate the positron angular distribution, which at low energies is slightly backward. We…
We propose a new method to calculate stellar weak-interaction rates. It is based on the Thermo-Field-Dynamics formalism and allows the calculation of the weak-interaction response of nuclei at finite temperatures. The thermal evolution of…
The description of nuclear reactions induced by supernova neutrinos has witnessed significant progress during the recent years. At the energies and momentum transfers relevant for supernova neutrinos neutrino-nucleus cross sections are…
Exchange current corrections are calculated using currents found from the hard-pion model and AV14+3BF wavefunctions. Results are given for the rate and spin observables. Their sensitivity to g_P, the nucleon pseudoscalar form factor, is…
At densities between 10^8 and 10^10} g/cm^3 electron capture in a presupernova collapse is believed to mainly occur on odd-odd nuclei. We have derived the rates for six of the most important electron capturing nuclei, {54,56,58}Mn and…
We propose a schematic model of nucleons moving in spin--orbit partner levels, $j=l\pm{\sfrac12}$, to explain Gamow--Teller and two-nucleon transfer data in $N=Z$ nuclei above $^{40}$Ca. Use of the $LS$ coupling scheme provides a more…
We study the process e^{-}e^{+} \to \tilde{\chi}^0_1\tilde{\chi}^0_2 with the subsequent decay \tilde{\chi}^0_2 \to \tilde{\chi}^0_1 \ell^{+}\ell^{-} taking into account the complete spin correlations between production and decay. We…
Gamow-Teller (GT) strength in $^{40}$Ar is studied by shell-model calculations with monopole-based universal intearction, which has tensor components of $\pi$\rho$-meson exchanges. Calculated GT strength is found to be consistent with the…
Muon capture on nuclei is one of the most promising probes of the nuclear electroweak current driving the yet-hypothetical neutrinoless double-beta ($0\nu\beta\beta$) decay. Both processes involve vector and axial-vector currents at finite…
We study total muon capture rates in light nuclei, taking into account renormalizations of the nuclear vector and axial vector strengths. We estimate the influence in the results of uncertainties of the spin-isospin interaction parameter…
This paper presents a systematic evaluation of the ability of theoretical models to reproduce experimental Gamow-Teller transition strength distributions measured via (n,p)-type charge-exchange reactions at intermediate beam energies. The…
By analyzing the energy-weighted moments of the strength function calculated in RPA and beyond it is shown that the explanation of the effect of missing strength of Gamow-Teller transitions requires that residual interaction produce…