Radiative and exchange corrections for two-neutrino double-β decay

AbstraktAbstract

We investigate the impact of radiative and atomic exchange corrections in the two-neutrino double-beta (2νββ) decay of Mo100. In the calculation of the exchange correction, the electron wave functions are obtained from a modified Dirac-Hartree-Fock-Slater self-consistent framework that ensures orthogonality between continuum and bound states. The atomic exchange correction causes a steep increase in the low-energy region of the single-electron spectrum, consistent with previous studies on β decay, while the radiative correction primarily accounts for a 5% increase in the decay rate of Mo100. When combined, the radiative and exchange effects cause a leftward shift of approximately 10 keV in the maximum of the summed electron spectrum. This shift may impact current constraints on parameters governing potential new physics scenarios in 2νββ decay. The exchange and radiative corrections are introduced on top of our previous description of 2νββ decay, where we used a Taylor expansion for the lepton energy parameters within the nuclear matrix elements denominators. This approach results in multiple components for each observable, controlled by the measurable ζ31 and ζ51 parameters. We explore the effects of different ζ31 and ζ51 values, including their experimental measurements, on the total corrected spectra. These refined theoretical predictions can serve as precise inputs for double-beta decay experiments investigating standard and new physics scenarios within 2νββ decay.

We investigate the impact of radiative and atomic exchange corrections in the two-neutrino double-beta (2νββ) decay of Mo100. In the calculation of the exchange correction, the electron wave functions are obtained from a modified Dirac-Hartree-Fock-Slater self-consistent framework that ensures orthogonality between continuum and bound states. The atomic exchange correction causes a steep increase in the low-energy region of the single-electron spectrum, consistent with previous studies on β decay, while the radiative correction primarily accounts for a 5% increase in the decay rate of Mo100. When combined, the radiative and exchange effects cause a leftward shift of approximately 10 keV in the maximum of the summed electron spectrum. This shift may impact current constraints on parameters governing potential new physics scenarios in 2νββ decay. The exchange and radiative corrections are introduced on top of our previous description of 2νββ decay, where we used a Taylor expansion for the lepton energy parameters within the nuclear matrix elements denominators. This approach results in multiple components for each observable, controlled by the measurable ζ31 and ζ51 parameters. We explore the effects of different ζ31 and ζ51 values, including their experimental measurements, on the total corrected spectra. These refined theoretical predictions can serve as precise inputs for double-beta decay experiments investigating standard and new physics scenarios within 2νββ decay.