相关论文: Possible solution to basic problems regarding the …
A precise measurement of the neutron decay $\beta$-asymmetry $A_0$ has been carried out using polarized ultracold neutrons (UCN) from the pulsed spallation UCN source at the Los Alamos Neutron Science Center (LANSCE). Combining data…
Calculation of ratio of the nucleon axial and vector coupling constants $G_A/G_V$ in the framework of the quasipotential quark model has been performed. It was shown that in this model $G_A/G_V$ is defined by the ratio of the corresponding…
The $O(\alpha)$ QED and electroweak radiative corrections to neutrino deuteron reactions is investigated with particular emphasis given to the constant terms, which have not been treated properly in the literature. This problem is related…
Calculations of the axial-vector component to the radiative correction for superallowed Fermi $0^+ \rightarrow 0^+$ nuclear beta decay are here modified with quenched rather than free-nucleon coupling constants for the axial-vector and…
Experimental studies of neutron decay, $n\to pe\bar\nu$, exhibit two anomalies. The first is a 8.6(2.1)s, roughly $4\sigma$ difference between the average beam measured neutron lifetime, $\tau_n^\text{beam}=888.0(2.0)$s, and the more…
Prompted by the level of accuracy now being achieved in tests of the unitarity of the CKM matrix, we consider the possible modification of the Fermi matrix element for the $\beta$-decay of a neutron, including possible in-medium and isospin…
We examine further corrections to the time component of the axial vector coupling constant in a nuclear medium. The dominant correction is that of exchange currents. The corrections we examine make the remaining discrepancy worse.
The nucleon axial coupling constant $g_A$ is calculated in the presence of an external uniform magnetic field using finite energy sum rules. The correlation function of proton, neutron and axial-vector currents is calculated both the…
Neutrons study a number of hot topics from the field of particle physics and cosmology: Recent measurements of various mixed American-British-French-German-Hungarian-Japan-Russian groups of researchers determine the strength of the weak…
The axial-vector coupling constant in nuclear medium is systematically studied using chiral perturbation theory. For normal nuclear matter, the first non-trivial corrections are estimated based on the independent particle approximation…
Data on superallowed Fermi beta decay in nuclei are compiled and electromagnetic corrections discussed. Recommended values for the weak vector coupling constant and the leading element of the Cabibbo-Kobayashi-Maskawa mixing matrix are…
There is a well known anomaly between the value of the Fermi decay constant extracted from super-allowed Fermi beta-decay of nuclear isotriplets and that required by unitarity of the Cabibbo-Kobayashi-Maskawa matrix. This discrepancy…
The universal radiative corrections common to neutron and super-allowed nuclear beta decays (also known as ``inner'' corrections) are revisited in light of a recent dispersion relation study that found $+2.467(22)\%$, i.e.~about $2.4\sigma$…
Measurements of $\beta$-spectral shapes is an important way to examine the effective value of the weak axial coupling $g_{\rm A}$. These stu\ dies focus specifically on forbidden non-unique $\beta^-$ transitions, as only in these cases is…
Detection of the neutrinoless $\beta\beta$ ($0\nu\beta\beta$) decay is of high priority in the particle- and neutrino-physics communities. The detectability of this decay mode is strongly influenced by the value of the weak axial-vector…
Determinations of $\vud$ and $\vus$ along with their implications for the unitarity test $\vud^2+\vus^2+\vub^2=1$ are discussed. The leading two loop radiative corrections to neutron $\beta$-decay are evaluated and used to derive a refined…
The neutron $\beta$-decay asymmetry parameter $A_0$ defines the correlation between the spin of the neutron and the momentum of the emitted electron, which determines $\lambda=\frac{g_{A}}{g_{V}}$, the ratio of the axial-vector to vector…
When scale symmetry is combined with chiral symmetry in a scale-chiral Lagrangian, it can be shown in Fermi-liquid fixed point theory that $g_A^{\rm eff}\approx 1$ in finite nuclei {\it as well as} in dense baryonic matter. This is…
Starting with the basic Lagrangian of the Standard Model, the radiative corrections to the neutron beta-decay are acquired. The electroweak interactions are consistently taken into consideration amenably to the Weinberg-Salam theory. The…
The $\textit{axial coupling of the nucleon}$, $g_A$, is the strength of its coupling to the $\textit{weak}$ axial current of the Standard Model of particle physics, in much the same way as the electric charge is the strength of the coupling…