Charge symmetry violation in the determination of strangeness form factors

Abstract

The strange quark contributions to the electromagnetic form factors of the proton are ideal quantities to study the role of hidden flavor in the properties of the proton. This has motivated intense experimental measurements of these form factors. A major remaining source of systematic uncertainty in these determinations is the assumption that charge symmetry violation (CSV) is negligible. We use recent theoretical determinations of the CSV form factors and reanalyze the available parity-violating electron scattering data, up to Q2≈1 GeV2. Our analysis considers systematic expansions of the strangeness electric and magnetic form factors of the proton. The results provide an update to the determination of strangeness over a range of Q2 where, under certain assumptions about the effective axial form factor, an emergence of nonzero strangeness is revealed in the vicinity of Q2≈0.6GeV2. Given the recent theoretical calculations, it is found that the current limits on CSV do not have a significant impact on the interpretation of the measurements and hence suggests an opportunity for a next generation of parity-violating measurements to more precisely map the distribution of strange quarks.