Dilepton photoproduction on a deuteron target

Carl E Carlson,Vladyslav Pauk,Marc Vanderhaeghen

doi:10.1016/j.physletb.2019.134872

Carl E Carlson, Vladyslav Pauk + Show 1 more

Open Access

https://doi.org/10.1016/j.physletb.2019.134872

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Abstract

We investigate the sensitivity of the cross section for lepton pair production off a deuteron target, γd→l+l−d, to the deuteron charge radius. We show that for small momentum transfers the Bethe-Heitler process dominates, and that it is sensitive to the charge radius such that a cross section ratio measurement of about 0.1% relative accuracy could give a deuteron charge radius more accurate than the current electron scattering value and sufficiently accurate to distinguish between the electronic and muonic atomic values.

Highlights

We investigate the sensitivity of the cross section for lepton pair production off a deuteron target, γd → l+l−d, to the deuteron charge radius
The extractions of the proton charge radius from the Lamb shift measurements in muonic hydrogen [1, 2] resulted in a significant discrepancy in comparison with measurements with electrons [3,4,5], amounting to a 5.6 σ difference according to a recent re-evaluation [6]
We investigate the sensitivity of the complementary lepton pair production process off a deuteron target, γd → l+l−d, to the deuteron charge radius

Summary

Introduction

We investigate the sensitivity of the cross section for lepton pair production off a deuteron target, γd → l+l−d, to the deuteron charge radius. The deuteron charge radius as extracted from elastic electron scattering [11] has at present a too large error bar to distinguish between both spectroscopic values.

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