Electroweak corrections to parity-violating neutral current scattering

Abstract

We analyze the degree to which parity-violating (PV) electroexcitation of the ∆(1232) resonance may be used to extract the weak neutral axial vector transition form factors. We find that the axial vector electroweak radiative corrections are large and theoretically uncertain, thereby modifying the nominal interpretation of the PV asymmetry in terms of the weak neutral form factors. We also show that, in contrast to the situation for elastic electron scattering, the axial N → ∆ PV asymmetry does not vanish at the photon point as a consequence of a new term entering the radiative corrections. We argue that an experimental determination of these radiative corrections would be of interest for hadron structure theory, possibly shedding light on the violation of Hara's theorem in weak, radiative hyperon decays.

Weak mixing angle at low energies

“…As an illustration, the SU 3 symmetric piece is well approxi- 11 This statement holds because small nonuniversal mass renormalization corrections from QED and the electroweak interactions can be neglected. 12 Exact SU 3 symmetry would imply M M ! ; since we are interested in an upper limit on the strange quark contribution we choose the (larger) phenomenological value of M !…”

“…(9). This is solved by, (12) or using the explicit solution to the one-loop RGE in Eq. (9) we obtain the simpler form,…”

Relativistic nuclear structure effects in quasielastic neutrino scattering

“…Most likely, it will take a large number of measurements to determine all of these form factors separately. Moreover, there are important complications from radiative corrections [2], which hinder the extraction of strange-quark matrix elements from parity violating electron scattering. Therefore, one anticipates a program of several electron experiments [3] which, combined with neutrino scattering data [4], will offer the most accurate strange-quark information.…”

Determination of the Strange Form Factors of the Nucleon fromνp,ν¯p, and Parity-Violatinge→Pate1 2004Phys. Rev. Lett.622670View full textAdd to dashboardCite

“…This last term G ewm A must be calculated in order to allow extraction of G s A from a measurement of G e A in elastic electron scattering. The difficulties in calculating this term have been noted already [9,12,13,14], and have played a role in recent experimental work. The SAMPLE experiment, which combined backward-angle electron-scattering data on proton and deuteron targets to extract G s M and G e A at Q 2 = 0.091 GeV 2 , originally reported [15] values of G s M = 0.14 ± 0.29 ± 0.31 and G e A = 0.22 ± 0.45 ± 0.39, which deviated from the calculated value [14] of G e A by 1.5σ and had the opposite sign.…”