1,913 research outputs found
Images of the Origin of Mass
Full text linkRecent years have brought considerable progress with studies of the
bound-state problem in continuum QCD. A small part of that made with Dyson
Schwinger equations is highlighted herein. Topics covered include:
opportunities provided by precision experimental studies of the (far) valence
region; and capitalising upon new data on hadron elastic and transition form
factors.Comment: 7 pages, 3 figures. Contribution to the Proceedings of MENU 2013 -
13th International Conference on Meson-Nucleon Physics and the Structure of
the Nucleon, Rome, 30 Sept. - 4. Oct. 201
Confinement, Diquarks and Goldstone's theorem
Full text linkDeterminations of the gluon propagator in the continuum and in lattice
simulations are compared. A systematic truncation procedure for the quark
Dyson-Schwinger and bound state Bethe-Salpeter equations is described. The
procedure ensures the flavour-octet axial-vector Ward identity is satisfied
order-by-order, thereby guaranteeing the preservation of Goldstone's theorem;
and identifies a mechanism that simultaneously ensures the absence of diquarks
in QCD and their presence in QCD, where the colour singlet diquark is
the ``baryon'' of the theory.Comment: 7 pages, LaTeX, uses sprocl.sty and epsfig, contribution to the
proceedings of ``Quark Confinement and the Hadron Spectrum'
Dyson-Schwinger Equations and the Quark-Gluon Plasma
Get PDFWe review applications of Dyson-Schwinger equations at nonzero temperature,
T, and chemical potential, mu, touching topics such as: deconfinement and
chiral symmetry restoration; the behaviour of bulk thermodynamic quantities;
the (T,mu)-dependence of hadron properties; and the possibility of diquark
condensation.Comment: 13 pages, 1 figure, LaTeX, sprocl.sty, epsfig.sty. Summary of
presentations by the authors at the Workshop "Understanding Deconfinement in
QCD", ECT*, Trento, 1-13/March, 199
Hadron Physics: The Essence of Matter
Full text linkDynamical chiral symmetry breaking (DCSB) is a remarkably effective mass
generating mechanism. It is also, amongst other things, the foundation for a
successful application of chiral effective field theories, the origin of
constituent-quark masses, and intimately connected with confinement in QCD.
Using the Dyson-Schwinger equations (DSEs), we explain the origin and nature of
DCSB, and elucidate some of its consequences, e.g.: a model-independent result
for the pion susceptibility; the generation of a quark anomalous chromomagnetic
moment, which may explain the longstanding puzzle of the a_1-rho mass
splitting; its impact on the behaviour of the electromagnetic pion form factor
-- thereby illustrating how data can be used to chart the momentum-dependence
of the dressed-quark mass function; in the form of the pion and kaon
valence-quark parton distribution functions, and the relation between them; and
aspects of the neutron's electromagnetic form factors, in particular
F_1^u/F_1^d and G_M^n. We argue that in solving QCD, a constructive feedback
between theory and extant and forthcoming experiments will most rapidly enable
constraints to be placed on the infrared behaviour of QCD's \beta-function, the
nonperturbative quantity at the core of hadron physics; and emphasise
throughout the role played by confrontation with data as a means of verifying
our understanding of Nature.Comment: 24 pages, 6 figures, 3 tables. Contribution to the proceedings of the
XII Mexican Workshop on Particles and Fields, based on presentations by
C.D.Roberts at the Workshop (9-14 Nov. 2009, Mazatlan, Mexico) and at the
preceding Mini-School (5-8 Nov. 2009, Culiacan, Mexico)
Flavour decomposition of electromagnetic transition form factors of nucleon resonances
Full text linkIn 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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