5,164 research outputs found
Dyson schwinger equations: Connecting small and large length-scales
I illustrate the phenomenological application of Dyson-Schwinger equations to
the calculation of meson properties observable at TJNAF. Particular emphasis is
given to this framework's ability to unify long-range effects constrained by
chiral symmetry with short-range effects prescribed by perturbation theory, and
interpolate between them.Comment: 8 pages, 3 figures, LaTeX, epsfig.sty. Summary of presentation at the
conference "Particle and nuclear physics with CEBAF at Jefferson Lab",
Dubrovnik, Croatia, November 3-10, 199
Images of the Origin of Mass
Recent 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
Determinations 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'
A century of Toxoplasma gondii research
Toxoplasma gondii (Fig. 1) is a protozoan parasite that can be transmitted directly from cats to humans through faecal contamination of food, or indirectly from cats to livestock and then to humans through undercooked meat. Around 30% of humans in the United Kingdom are infected, and as such, harbour dormant cysts in their brain, but few have overt symptoms of disease. Neurological disease can occur in these people if they become immunosuppressed (Fig. 2). The possibility that apparently healthy people with infection are more likely to develop psychiatric disease, including schizophrenia and depression, is under investigation. Infection during pregnancy can cause abortion or foetal infection. Congenital disease can result in systemic, neurological and progressive eye disease
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