369 research outputs found
Compact lattice U(1) and Seiberg-Witten duality: a quantitative comparison
It was conjectured some time ago that an effective description of the
Coulomb-confinement transition in compact U(1) lattice gauge field theory could
be described by scalar QED obtained by soft breaking of the N=2 Seiberg-Witten
model down to N=0 in the strong coupling region where monopoles are light. In
two previous works this idea was presented at a qualitative level. In this work
we analyze in detail the conjecture and obtain encouraging quantitative
agreement with the numerical determination of the monopole mass and the dual
photon mass in the vicinity of the Coulomb to confining phase transition.Comment: 14 pag, 5 figure
Vector mesons in the Extended Chiral Quark Model
We extend our previous formulation of low-energy QCD in terms of an effective
lagrangian containing operators of dimensionality constructed with
pseudoscalars and quark fields, describing physics below the scale of chiral
symmetry breaking. We include in this paper the vector and axial-vector
channels. We follow closely the Extended Chiral Quark Model approach and
consistently work in the large- and leading log approximation and take
into account the constraints from chiral symmetry and chiral symmetry
restoration. The optimal fit of all parameters gives further support to a heavy
scalar meson with a mass GeV and a value of the axial pion-quark
coupling constant to 0.66, depending on some assumptions
concerning the Weinberg sum rules.Comment: 19 pages, Latex, JHEP class, more typos removed, few refs.adde
Axions and high-energy cosmic rays: Can the relic axion density be measured?
In a previous work we investigated the propagation of fast moving charged
particles in a spatially constant but slowly time dependent pseudoscalar
background, such as the one provided by cold relic axions. The background
induces cosmic rays to radiate in the low-energy spectrum. While the energy
loss caused by this mechanism on the primary cosmic rays is negligible, we
investigate the hypothetical detection of the photons radiated and how they
could provide an indirect way of verifying the cosmological relevance of
axions. Assuming that the cosmic ray flux is of the form J(E)~ E^-g we find
that the energy radiated follows a distribution k^-((g-1)/2) for proton
primaries, identical to the Galaxy synchrotron radiation that is the main
background, and k^-(g/2) for electron primaries, which in spite of this sharper
decay provide the dominant contribution in the low-energy spectrum. We discuss
possible ways to detect this small diffuse contribution. Local detection in the
vicinity of powerful cosmic rays emitters might also be possible.Comment: plot improved with background and comments adde
Stringification of Chiral Dynamics: Wess-Zumino interaction
The QCD hadronic string is supplemented with the reparameterization-invariant
boundary interaction to background chiral fields associated with pions in a way
compatible with the conformal symmetry. It allows the full reconstruction of
the P-even part of the Chiral Lagrangian in a good agreement with the
phenomenology of P-even meson interactions. The modification of boundary
interaction necessary to induce the parity-odd Chiral Dynamics (WZW action) is
outlined.Comment: 5 pages, misprints removed, Talks at the 1th Workshop on Hadron
Structure and QCD, 18-22.May 2004, St.Petersburg, Russia, at the Bogolubov
Conference on Problems of Theoretical and Mathematical Physics, 2-6.September
2004, Dubna, Russia and at the 6th Conference on Quark Confinement and the
Hadron Spectrum, 21-25.September 2004, Villasimius, Sardegna, Ital
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