نتایج جستجو برای: neutron decay
تعداد نتایج: 117888 فیلتر نتایج به سال:
Recent timing observations of PSR J0045-7319 reveal that the neutron star/B star binary orbit is decaying on a time scale of |Porb/Ṗorb| = 0.5 Myr, shorter than the characteristic age (τc = 3 Myr) of the pulsar (Kaspi et al. 1996a). We study mechanisms for the orbital decay. The standard weak friction theory based on static tide requires far too short a viscous time to explain the observed Ṗorb...
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 gA extracted from the beta asymmetry so that it ties to gA that appears in neutron decay lifetime in a consistent renormalisation scheme. We find that the ratio of axial-vector...
Standard GRB fireballs must carry free neutrons. This crucially changes the mechanism of fireball deceleration by an external medium. As the ion fireball decelerates, the coasting neutrons form a leading front. They gradually decay, leaving behind a relativistic trail of decay products mixed with the ambient medium. The ion fireball sweeps up the trail and drives a shock wave in it. Thus, obser...
The β-decay half-lives of 38 neutron-rich isotopes from (36)Kr to (43)Tc have been measured; the half-lives of (100)Kr, (103-105)Sr, (106-108)Y, (108-110)Zr, (111,112)Nb, (112-115)Mo, and (116,117)Tc are reported here. The results when compared with previous standard models indicate an overestimation in the predicted half-lives by a factor of 2 or more in the A≈110 region. A revised model based...
New generation of neutron decay experiments, which can be done with high accuracy at new Spallation Neutron Sources, are very important for solution of current problems of fundamental physics and for tests of the Standard Model. The open problems of theory related to these experiments and possible approaches to their solutions are
In former papers we showed that during the decay of a neutron star’s magnetic field under the influence of the Hall–drift, an unstable rise of small–scale field structures at the expense of the large–scale background field may happen. This linear stability analysis was based on the assumption of a uniform density throughout the neutron star crust, whereas in reality the density and all transpor...
We describe an asymptotic analysis of the coupled nonlinear system of equations describing time-dependent three-dimensional monoenergetic neutron transport and isotopic depletion and radioactive decay. The classic asymptotic diffusion scaling of Larsen and Keller [1], along with a consistent small scaling of the terms describing the radioactive decay of isotopes, is applied to this coupled nonl...
We propose that accretion can induce a neutron star magnetic field decay because the ferromagnetic accreted matter screens the magnetic field of neutron star. Our model results suggest that: (i) the surface magnetic field decay is inversely correlated with the accretion mass in the X-ray binary accretion phase as∆M−0.4, (ii) the ‘Bottom Field Strength ’ of about 108 G can occur when the accrete...
We report the preparation of neutron-activated xenon for the calibration of liquid xenon (LXe) detectors. Gamma rays from the decay of xenon metastable states, produced by fast neutron activation, were detected and their activities measured in a LXe scintillation detector. Following a five-day activation of natural xenon gas with a Cf (4× 10 n/s) source, the activities of two gamma ray lines at...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید