Related papers: Neutron Lifetime and Axial Coupling Connection
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 reviews the puzzles in modern neutron lifetime measurements and related unitarity issues in the CKM matrix. It is not a comprehensive and unbiased compilation of all historic data and studies, but rather a focus on compelling…
A neutron decays into a proton, an electron, and an anti-neutrino through the beta-decay process. The decay lifetime ($\sim$880 s) is an important parameter in the weak interaction. For example, the neutron lifetime is a parameter used to…
The existing experimental evidence on the vector and axial-vector coupling constants, $G_V$ and $G_A$, for neutron $\beta$-decay exhibits two prominent problems: (i) the unitarity for the first row of the CKM matrix seems violated; (ii) one…
We report a new measurement of the neutron lifetime using ultra-cold neutrons stored in a magneto-gravitational trap made of permanent magnets. Neutrons surviving in the trap after fixed storage times have been counted and the trap losses…
All existing "positive" results on two neutrino double beta decay in different nuclei were analyzed. Using procedure recommended by Particle Data Group weighted average values for half-lives of $^{48}$Ca, $^{76}$Ge, $^{82}$Se, $^{96}$Zr,…
There is a long-standing discrepancy between the neutron lifetime measured in beam and bottle experiments. We propose to explain this anomaly by a dark decay channel for the neutron, involving one or more dark sector particles in the final…
A model of $n-n'$ (neutron-mirror neutron) oscillations is proposed under the framework of the mirror matter theory with slightly broken mirror symmetry. It resolves the neutron lifetime discrepancy, i.e., the 1% difference in neutron…
The experimental determination of V_{ud} from neutron beta decay requires accurate values of the neutron lifetime and the ratio of the weak axial-vector to vector coupling constants of the nucleon. The latter is derived from measurements of…
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…
Precision measurements of the free neutron lifetime $\tau_n$, when combined with measurements of the axial vector form factor, can be used to test unitarity of the CKM matrix. Non-unitarity is a signal for physics Beyond the Standard Model…
We review the current status of precision measurements in allowed nuclear beta decay, including neutron decay, with emphasis on their potential to look for new physics beyond the standard electroweak model. The experimental results are…
The manuscript by Berezhiani (arXiv:1812.11089) proposes a model that has the neutron decaying into a mirror neutron with a branching fraction of 1%, alleviating the tension between neutron lifetime measurements in beam vs bottle…
We revisit the neutron lifetime puzzle, a discrepancy between beam and bottle measurements of the weak neutron decay. Since both types of measurements are realized at different times after the nuclear production of free neutrons, we argue…
There exists a puzzling disagreement between the results for the neutron lifetime obtained in experiments using the beam technique versus those relying on the bottle method. A possible explanation of this discrepancy postulates the…
We derive new constraints on the neutron lifetime based on the recent Planck 2015 observations of temperature and polarization anisotropies of the CMB. Under the assumption of standard Big Bang Nucleosynthesis, we show that Planck data…
All existing ``positive'' results on two neutrino double beta decay in different nuclei were analyzed. Using the procedure recommended by the Particle Data Group, weighted average values for half-lives of $^{48}$Ca, $^{76}$Ge, $^{82}$Se,…
The puzzle remains in the large discrepancy between neutron lifetime measured by the two distinct experimental approaches -- counts of beta decays in a neutron beam and storage of ultracold neutrons in a potential trap, namely, the beam…
All existing ``positive'' results on two neutrino double beta decay in different nuclei were analyzed. Using the procedure recommended by the Particle Data Group, weighted average values for half-lives of $^{48}$Ca, $^{76}$Ge, $^{82}$Se,…
We performed a detailed analysis and the Monte Carlo simulation of the neutron lifetime experiment [S. Arzumanov et al., Phys. Lett. B 483 (2000) 15] because of the strong disagreement by 5.6 standard deviations between the results of this…