Electroexcitation of the Δ + (1232) at low momentum transfer
Name
1-s2.0-S0370269316303367-main.pdf
Description
Published version
Size
732.65 KB
Format
Unknown
Checksum (MD5)
747138580c61ae2a5574a906fd38413d
Author(s)
Gilad, Shalev
Pan, Kai
Date Issued
2016
Journal
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Publisher
Elsevier BV
Version
Final published version
Abstract
© 2016 The Authors We report on new measurements at the resonance at the low momentum transfer region, where the mesonic cloud dynamics is predicted to be dominant and rapidly changing, offering a test bed for chiral effective field theory calculations. The new data explore the dependence of the resonant quadrupole amplitudes and for the first time indicate that the Electric and the Coulomb quadrupole amplitudes converge as. The measurements of the Coulomb quadrupole amplitude have been extended to the lowest momentum transfer ever reached, and suggest that more than half of its magnitude is attributed to the mesonic cloud in this region. The new data disagree with predictions of constituent quark models and are in reasonable agreement with dynamical calculations that include pion cloud effects, chiral effective field theory and lattice calculations. The measurements indicate that improvement is required to the theoretical calculations and provide valuable input that will allow their refinements.
MIT Department
Massachusetts Institute of Technology. Department of Physics
Terms of Use
Creative Commons Attribution 4.0 International license
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1016/J.PHYSLETB.2016.06.076
