Proton-proton fusion in pionless effective theory

TL;DR

This paper presents a pionless effective field theory calculation of proton-proton fusion, achieving high accuracy and simplifying the process by resumming effective range corrections with di-baryon fields.

Contribution

It introduces a parameter-free pionless EFT approach with di-baryon fields for proton-proton fusion, improving calculation simplicity and accuracy over previous methods.

Findings

Achieves better than 1% agreement with potential model results.

Resums effective range corrections to all orders.

Fixes low-energy constants using tritium lifetime data.

Abstract

The proton-proton fusion reaction, $pp\to de^+\nu$, is studied in pionless effective field theory (EFT) with di-baryon fields up to next-to leading order. With the aid of the di-baryon fields, the effective range corrections are naturally resummed up to the infinite order and thus the calculation is greatly simplified. Furthermore, the low-energy constant which appears in the axial-current-di-baryon-di-baryon contact vertex is fixed through the ratio of two- and one-body matrix elements which reproduces the tritium lifetime very precisely. As a result we can perform a parameter free calculation for the process. We compare our numerical result with those from the accurate potential model and previous pionless EFT calculations, and find a good agreement within the accuracy better than 1%.