Proton-electron mass ratio from HD$^+$ revisited

TL;DR

This paper refines the proton-electron mass ratio using precise theoretical adjustments to HD$^+$ molecular data, incorporating updated fundamental constants, resulting in a revised value with increased uncertainty.

Contribution

It introduces a new derivation method for the mass ratio that accounts for recent theoretical and fundamental constant updates, differing from previous approaches.

Findings

Revised proton-electron mass ratio with larger uncertainty

Adjusted sensitivity coefficients due to updated constants

Enhanced agreement with recent theoretical improvements

Abstract

We present a new derivation of the proton-electron mass ratio from the hydrogen molecular ion, HD$^+$. The derivation entails the adjustment of the mass ratio in highly precise theory so as to reproduce accurately measured ro-vibrational frequencies. This work is motivated by recent improvements of the theory, as well as the more accurate value of the electron mass in the recently published CODATA-14 set of fundamental constants, which justifies using it as input data in the adjustment, rather than the proton mass value as done in previous works. This leads to significantly different sensitivity coefficients and, consequently, a different value and larger uncertainty margin of the proton-electron mass ratio as obtained from HD$^+$.