Nuclear matrix elements(NME) and phase space factors(PSF) entering the half-life formulas of the double-beta decay(DBD) process are two key quantities whose accurate computation still represents a challenge. In this s...Nuclear matrix elements(NME) and phase space factors(PSF) entering the half-life formulas of the double-beta decay(DBD) process are two key quantities whose accurate computation still represents a challenge. In this study, we propose a new approach of calculating these, namely the direct computation of their product as an unique formula. This procedure allows a more coherent treatment of the nuclear approximations and input parameters appearing in both quantities and avoids possible confusion in the interpretation of DBD data due to different individual expressions adopted for PSF and NME(and consequently their reporting in different units) by different authors. Our calculations are performed for both two neutrino(2 vββ) and neutrinoless(0 vββ) decay modes, for five nuclei of the most experimental interest. Further, using the most recent experimental limits for 0νββ decay half-lives,we provide new constraints on the light mass neutrino parameter. Finally, by separating the factor representing the axial-vector constant to the forth power in the half-life formulas, we advance suggestions on how to reduce the errors introduced in the calculation by the uncertain value of this constant, exploiting the DBD data obtained from different isotopes and/or decay modes.展开更多
This paper studies the conformed invariance and conserved quantities of general holonomic systems in phase space. The definition and the determining equation of conformed invariance for general holonomic systems in ph...This paper studies the conformed invariance and conserved quantities of general holonomic systems in phase space. The definition and the determining equation of conformed invariance for general holonomic systems in phase space are provided. The conformed factor expression is deduced from conformed invariance and Lie symmetry. The relationship between the conformed invariance and the Lie symmetry is discussed, and the necessary and sufficient condition that the conformal invariance would be the Lie symmetry of the system under the infinitesimal single-parameter transformation group is deduced. The conserved quantities of the system are given. An example is given to illustrate the application of the result.展开更多
基金Supported by Ministry of Research and Innovation through UEFISCDI,project PCE-2016-0078,contract 198/2017
文摘Nuclear matrix elements(NME) and phase space factors(PSF) entering the half-life formulas of the double-beta decay(DBD) process are two key quantities whose accurate computation still represents a challenge. In this study, we propose a new approach of calculating these, namely the direct computation of their product as an unique formula. This procedure allows a more coherent treatment of the nuclear approximations and input parameters appearing in both quantities and avoids possible confusion in the interpretation of DBD data due to different individual expressions adopted for PSF and NME(and consequently their reporting in different units) by different authors. Our calculations are performed for both two neutrino(2 vββ) and neutrinoless(0 vββ) decay modes, for five nuclei of the most experimental interest. Further, using the most recent experimental limits for 0νββ decay half-lives,we provide new constraints on the light mass neutrino parameter. Finally, by separating the factor representing the axial-vector constant to the forth power in the half-life formulas, we advance suggestions on how to reduce the errors introduced in the calculation by the uncertain value of this constant, exploiting the DBD data obtained from different isotopes and/or decay modes.
基金supported by the Key Disciplines’ Building Foundation of Henan Institute of Education,the Natural Science Foundation f Education Bureau of Henan Province,China (Grant No 2009A140003)
文摘This paper studies the conformed invariance and conserved quantities of general holonomic systems in phase space. The definition and the determining equation of conformed invariance for general holonomic systems in phase space are provided. The conformed factor expression is deduced from conformed invariance and Lie symmetry. The relationship between the conformed invariance and the Lie symmetry is discussed, and the necessary and sufficient condition that the conformal invariance would be the Lie symmetry of the system under the infinitesimal single-parameter transformation group is deduced. The conserved quantities of the system are given. An example is given to illustrate the application of the result.
