Neutrino rest mass

If a supernova emits gravitational waves as well as neutrinos, the gravitational waves will reach Earth-bound detectors slightly earlier because of the finite neutrino rest-mass. Assuming a supernova goes off at a distance of 100 Mpc, and a neutrino rest-mass of 0.1 eV, find the time delay for neutrino energies of 1 MeV and 10 MeV respectively. 

Relaxing the restriction that the neutrino rest mass is zero, we get (Heyde, 1999)... 

Decay-Induced Rearrangement of the Molecular Electron Shell and the Problem of Determining the Neutrino Rest Mass... 

To find the average energy transferred to the electronic-vibrational molecular degrees of freedom, it is necessary to know the distribution of the probabilities of formation of the daughter molecule in different final states. This energy is of the same order of magnitude as the expected value of the neutrino rest mass, and at attained energy resolutions must be, naturally, taken into account in the reduction of the experimental (3 spectrum. 

Qualitatively new results concerning the determination of the neutrino rest mass were obtained in 1980, when the data reduction of a set of experiments performed for more than 5 years at the Moscow Institute of Theoretical and Experimental Physics (ITEP) (Lubimov et al, 1980, 1981) for the first time give the lower limit on the neutrino rest mass. The /J-electron source was a doubly tritrated amino acid, valine (C5HnN02). The early reductions of the results obtained in these experiments have shown that the confidence interval for the neutrino mass substantially depends on the chosen theoretical model. Since the real electron excitation spectrum of the / source was not known, the experimental data were reduced for two model cases ... 

The Most Probable Value of the Neutrino Rest Mass"... 

The results concerning the allowance for the / -source molecular structure (Kaplan et al., 1982,1983) were used in reduction of the new experimental data obtained by the ITEP group. Table I (Boris et al., 1983) shows the most probable values of the neutrino rest mass obtained by data reduction using the models of a bare nucleus, of a tritium atom, and of a real valine molecule. The reduction of the new experimental data within the bare-nucleus model did not lead to a nonzero rest mass of the neutrino. The allowance for the electron structure of valine gives mvc2 = 33 eV.2 Thus, the quantum chemical calculations proved to be a necessary step in the reduction of the data concerning the properties of an elementary particle. 

One might estimate the value of the neutrino rest mass by the changes in the /i spectrum. However, the direct measurements are not possible, since at the high-energy edge of the fi spectrum, where the effect of the nonzero mv is manifest, the intensity of the spectrum is very low and is well below the level of the apparatus noise. Such experiments require a highly sensitive technique and... 

In Section I we made a brief excursion into the history of studies devoted to the estimation of the neutrino rest mass in this regard we pointed out the importance of the problem, first raised by Bergkvist (1971, 1972), of taking... 

In this section we present the calculation (Kaplan et al, 1982,1983, 1985) of parameters describing the excitations of the P source used by the ITEP group in a series of experiments for measuring the neutrino rest mass. The results of these calculations were used by the ITEP group for data reduction and estimation of mv. 

In work by Kaplan et al. (1984) the ji decay in a valine molecule was calculated with allowance for electron correlation. The method of calculation is presented in Section II,C,4. We have taken 50 configurations which give the largest contribution to the excitation probabilities. The results of calculations for valine II are presented in Table VIII (the numbers in parentheses) and in the histogram of Fig. 10. These results have been used by the ITEP group (Boris et al., 1983) in data reduction of their latest series of experiments. (The obtained values of the neutrino rest mass mv are presented in Table I.)... 

The effect of electron excitations of the / source is comparable in magnitude with the expected value of the neutrino rest mass and is manifested in the region most sensitive to the nonzero mv. The allowance for the molecular structure of the / source in reduction of the experimental data of the ITEP group has led to the most probable value of the neutrino rest mass mv = 33 eV (Boris et al., 1983). 

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