相关论文: Neutron lifetime anomaly and mirror matter theory
It was recently suggested that the discrepancy between two methods of measuring the lifetime of the neutron may be a result of an unseen decay mode into a dark matter particle which is almost degenerate with the neutron. We explore the…
The purpose of this paper is to demonstrate that if the transformation of a neutron to a mirror neutron exists with an oscillation time of the order of ten seconds, it can be detected in a rather simple disappearance and/or regeneration…
Future cosmological data may be sensitive to the effects of a finite sum of neutrino masses even as small as ~0.06 eV, the lower limit guaranteed by neutrino oscillation experiments. We show that a cosmological detection of neutrino mass at…
The precise value of the neutron lifetime is of fundamental importance to particle physics and cosmology. The neutron lifetime recently obtained, 878.5 +/- 0.7stat +/- 0.3sys s, is the most accurate one to date. The new result for the…
High precision measurements of isospin $T=1/2$ decays in the neutron and nuclei provide strong model-independent constraints on extensions to the standard model of particle physics. A measurement of the $\beta$-asymmetry in $^{19}$Ne decay…
At present, the strongest upper limit on $\sum m_{\nu}$, the sum of neutrino masses, is from cosmological measurements. However, this bound assumes that the neutrinos are stable on cosmological timescales, and is not valid if the neutrino…
The lifetime of free neutrons measured in the lab has a long standing disparity of $\sim$9~s. A space-based technique has recently been proposed to independently measure the neutron lifetime using interactions between the galactic cosmic…
We derive new constraints on the neutron lifetime based on the recent Planck 2015 observations of temperature and polarization anisotropies of the CMB. Under the assumption of standard Big Bang Nucleosynthesis, we show that Planck data…
The past two decades have yielded several new measurements and reanalyses of older measurements of the neutron lifetime. These have led to a 4.4 standard deviation discrepancy between the most precise measurements of the neutron decay rate…
We present the status of current US experimental efforts to measure the lifetime of the free neutron by the "beam" and "bottle" methods. BBN nucleosynthesis models require accurate measurements with 1 second uncertainties, which are…
We performed ultracold neutron (UCN) storage measurements to search for additional losses due to neutron (n) to mirror-neutron (n') oscillations as a function of an applied magnetic field B. In the presence of a mirror magnetic field B',…
Discrepancies from in-beam and in-bottle type experiments measuring the neutron lifetime are on the 4$\sigma$ standard deviation level. In a recent publication Fornal and Grinstein proposed that the puzzle could be solved if the neutron…
We comment on a recently discussed possibility of oscillations between neutrons and degenerate mirror neutrons in the context of mirror models for particles and forces. It has been noted by Bento and Berezhiani that if these oscillations…
The unitarity of the lepton mixing matrix is a critical assumption underlying the standard neutrino-mixing paradigm. However, many models seeking to explain the as-yet-unknown origin of neutrino masses predict deviations from unitarity in…
It was pointed out in a recent paper that the observed cooling rate of old, cold neutron stars (NS) can provide an upper limit on the transition rate of neutron to mirror neutron ($n-n'$). This limit is so stringent that it would preclude…
An observation of neutron-antineutron oscillations ($ n-\bar{n}$), which violate both $B$ and $B-L$ conservation, would constitute a scientific discovery of fundamental importance to physics and cosmology. A stringent upper bound on its…
The analysis of the data on measurements of the neutron lifetime is presented. A new most accurate result of the measurement of neutron lifetime [Phys. Lett. B 605 (2005) 72] 878.5 +/- 0.8 s differs from the world average value [Phys. Lett.…
A new tension is emerging between the tight cosmological upper bounds on the total neutrino mass ($\sum m_\nu \lesssim 0.06 \, \rm{eV}$) and the lower limits from oscillation experiments, with potentially far-reaching implications for…
We report an improved measurement of the free neutron lifetime $\tau_{n}$ using the UCN$\tau$ apparatus at the Los Alamos Neutron Science Center. We counted a total of approximately $38\times10^{6}$ surviving ultracold neutrons (UCN) after…
We explore the cosmological signals of theories in which the neutrinos decay into invisible dark radiation after becoming non-relativistic. We show that in this scenario, near-future large scale structure measurements from the Euclid…