nucl-th digest · Jul 22, 2022

Theoretical evaluation of solar proton-proton fusion reaction rate and its uncertainties

The weak proton-proton fusion into a deuteron ( $^{2}$ H) is the driving reaction in the energy production in the Sun, as well as similar main sequence stars. Its reaction rate in the solar interior is determined only theoretically. Here, we provide a new determination of the rate of this reaction in solar conditions $S^{11} (0)$ , and analyze theoretical and experimental sources for uncertainties, using effective field theory of quantum chromo-dynamics without explicit pions at next-to-leading order. We find an enhancement of $S^{11}$ by $1 - 4%$ over the previously recommended value. This change reduces the calculated fluxes of neutrinos originating in $^{8}$ B and $^{7}$ Be nuclear reactions in the Sun, thus favoring higher abundances for metallic photospheric elements, in the tension between different composition determination, known as the ``Solar Composition Problem''.

nucl-thastro-ph.SRPLB(2023)·7 citations

Triaxiality explored by an odd quasi-particle

The triaxiality of odd-mass nuclei is investigated by coupling a quasiparticle to an even-even core through the core-quasiparticle coupling model. Both soft and rigid triaxial cores are considered. The "soft core" is described by the collective model with rotation-vibrational motion, while the "rigid core" is described by the triaxial rotor model, which is a limiting case of the collective model with only rotational motion. We show that the presence of the odd quasiparticle modifies the collective quadrupole dynamics of the core to appear more "rigid".

nucl-thnucl-ex5 citations

Friday·July 22, 2022

Theoretical evaluation of solar proton-proton fusion reaction rate and its uncertainties

Triaxiality explored by an odd quasi-particle

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