相关论文: Sharpening Low-Energy, Standard-Model Tests via Co…
The matrix element \Vud of the CKM matrix can be determined by two independent measurements in neutron decay: the neutron lifetime $\tau_n$ and the ratio of coupling constants $\lambda=g_A/g_V$, which is most precisely determined by…
Background: Time-reversal-invariance violation, or equivalently CP violation, may explain the observed cosmological baryon asymmetry as well as signal physics beyond the Standard Model. In the decay of polarized neutrons, the triple…
Precision studies of $0^{+} \rightarrow 0^{+}$ superallowed $\beta$ decays provide the necessary data to test stringently the CVC hypothesis. They will also provide a value for the weak vector coupling constant and the $V_{ud}$ quark mixing…
We give a precision analysis of the correlation coefficients of the electron-energy spectrum and angular distribution of the beta decay and radiative beta decay of the neutron with polarized neutron and electron to order 10^(-3). The…
In this work, the recoil corrections to the correlation coefficients in the neutron beta decay with polarized neutron and electron are evaluated to order O(m_n^-2) in the Born approximation. Different from the usual calculations applied in…
The beta-ray angular correlations for the spin alignments of 8Li and 8B have been observed in order to test the conserved vector current (CVC) hypothesis. The alignment correlation terms were combined with the known beta-alpha-angular…
The nucleon axial-vector coupling constant $g_A$ is studied in the presence of an external magnetic field, and in dense nuclear environments, to emulate nuclear matter in magnetars. For this purpose we use QCD finite energy sum rules for…
Superallowed $0^+ \to 0^+$ nuclear beta decay provides a direct measure of the weak vector coupling constant, $\GV$. We survey current world data on the nine accurately determined transitions of this type, which range from the decay of…
Precision measurements in nuclear beta decay offer a sensitive window to search for new physics beyond the standard electroweak model and allow also the determination of the fundamental weak vector coupling in processes involving the…
The aCORN experiment measures the neutron decay electron-antineutrino correlation ($a$-coefficient) using a novel method based on an asymmetry in proton time-of-flight for events where the beta electron and recoil proton are detected in…
This paper gives a brief overview of the present and expected future limits on physics beyond the Standard Model (SM) from neutron beta decay, which is described by two parameters only within the SM. Since more than two observables are…
Precision measurements in allowed nuclear beta decays and neutron decay are reviewed and analyzed both within the Standard Model and looking for new physics. The analysis incorporates the most recent experimental and theoretical…
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…
The correlations of the decay products following the beta decay of nuclei have a long history of providing a low-energy probe of the fundamental symmetries of our universe. Over half a century ago, the correlation of the electrons following…
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…
The abBA collaboration proposes to conduct a comprehensive program of precise measurements of neutron $\beta$-decay coefficients $a$ (the correlation between the neutrino momentum and the decay electron momentum), $b$ (the electron energy…
Precision measurements in neutron beta decay serve to determine the coupling constants of beta decay and allow for several stringent tests of the standard model. This paper discusses the design and the expected performance of the Nab…
We consider neutron radiative \beta-decay, n\to p e^- \bar{\nu}_e\gamma, and compute the T-odd momentum correlation in the decay rate characterized by the kinematical variable \xi = {\bf l}_\nu \cdot ({\bf l}_e\times{\bf k}) arising from…
The proton asymmetry parameter C in neutron decay describes the correlation between neutron spin and proton momentum. In this Letter, the first measurement of this quantity is presented. The result C=-0.2377(26) agrees with the Standard…
We present a calculation of full one-loop radiative corrections, including the constant term, to the asymmetry parameter of polarised neutron beta decay. This gives the radiative correction to the axial coupling constant $g_A$ extracted…