526 research outputs found
Strong diquark correlations inside the proton
Quantum Chromodynamics is thought to be the relativistic quantum field theory
that describes the strong interaction of the Standard Model. This interaction
produces mesons but it is also able to generate quark-quark (diquark)
correlations inside baryons. In this work, we employ a continuum approach to
QCD based on Dyson-Schwinger equations to calculate the electromagnetic form
factors of the proton and analyze in a deeper way the consequences of having
strong diquark correlations. Comparison with the experimental data reveals that
the presence of strong diquark correlations within the proton is sufficient to
understand empirical extractions of the flavour-separated form factors. The
explained reduction of the ratios and
at high in the quark-diquark picture are
responsible of the precocious scaling of the observed
experimentally.Comment: To be published in the proceedings of 21st International Conference
on Few-Body Problems in Physics, Chicago, IL, 18-22 May 201
pNRQCD determination of E1 radiative transitions
This contribution contains the first numerical computation of the complete
set of relativistic corrections of relative order for electric dipole
(E1) transitions in heavy quarkonium; in particular, for the processes
with . We assume that
the momentum transfer of the heavy mesons involved in the reactions lies in the
weak-coupling regime of the low-energy effective field theory potential
non-relativistic QCD (pNRQCD) and thus a full perturbative calculation can be
performed.Comment: Contribution to the proceedings of the 12th Quark Confinement and the
Hadron Spectrum (CONF12). Aug. 28 - Sep. 4, 2016. Thessaloniki, Greec
Flavour decomposition of electromagnetic transition form factors of nucleon resonances
In Poincar\'e-covariant continuum treatments of the three valence-quark
bound-state problem, the force behind dynamical chiral symmetry breaking also
generates nonpointlike, interacting diquark correlations in the nucleon and its
resonances. We detail the impact of these correlations on the nucleon's elastic
and nucleon-to-Roper transition electromagnetic form factors, providing
flavour-separation versions that can be tested at modern facilities.Comment: Contribution to the proceedings of the 12th Quark Confinement and the
Hadron Spectrum (CONF12). Aug. 28 - Sep. 4, 2016. Thessaloniki, Greece. arXiv
admin note: text overlap with arXiv:1602.02768, arXiv:1508.0240
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