1,507 research outputs found
On NCQFT and dimensionless insertions
In these notes, we aim at a precise definition of the tree level action for
the noncommutative scalar and gauge field theories on four-dimensional
canonically deformed Euclidean space. As tools to achieve this goal we employ
power counting and normalization conditions.Comment: 10 page
Mott effect at the chiral phase transition and anomalous J/Psi suppression
We investigate the in-medium modification of the charmonium break-up
processes due to the Mott effect for light (pi) and open-charm (D, D*) mesons
at the chiral/deconfinement phase transition. A model calculation for the
process J/Psi + pi -> D + \bar D* + h.c. is presented which demonstrates that
the Mott effect for the D-mesons leads to a threshold effect in the thermal
averaged break-up cross section. This effect is suggested as an explanation of
the phenomenon of anomalous J/Psi suppression in the CERN NA50 experiment.Comment: 9 pages, 3 figures; final version to appear in Phys. Lett.
Mott dissociation of D-mesons at the chiral phase transition and anomalous J/Psi suppression
We investigate the in-medium modification of the charmonium breakup processes
due to the Mott-effect for D-mesons at the chiral phase transition. A model
calculation for the process J/Psi+pi --> D+D^*+ h.c. is presented which
demonstrates that threshold effects in the thermal averaged breakup cross
section can be explained as a Mott transition where final state quark-antiquark
bound states enter the continuum of resonant states at the QCD phase
transition. Applications to heavy-ion collisions within a modified Glauber
model scenario and the phenomenon of anomalous J/ suppression in the CERN
NA50 experiment are addressed.Comment: 5 pages, 4 figures, uses JHEP.cls styl
A New Approach to Non-Commutative U(N) Gauge Fields
Based on the recently introduced model of arXiv:0912.2634 for non-commutative
U(1) gauge fields, a generalized version of that action for U(N) gauge fields
is put forward. In this approach to non-commutative gauge field theories, UV/IR
mixing effects are circumvented by introducing additional 'soft breaking' terms
in the action which implement an IR damping mechanism. The techniques used are
similar to those of the well-known Gribov-Zwanziger approach to QCD.Comment: 11 pages; v2 minor correction
Coexistence of color superconductivity and chiral symmetry breaking within the NJL model
The phase diagram for quark matter is investigated within a simple
Nambu-Jona-Lasinio model without vector correlations. It is found that the
phase structure in the temperature-density plane depends sensitively on the
parametrization of the model. We present two schemes of parametrization of the
model where within the first one a first order phase transition from a phase
with broken chiral symmetry to a color superconducting phase for temperatures
below the triple point at T_t= 55 MeV occurs whereas for the second one a
second order phase transition for temperatures below T_t = 7 MeV is found. In
the latter case, there is also a coexistence phase of broken chiral symmetry
with color superconductivity, which is a new finding within this class of
models. Possible consequences for the phenomenology of the QCD phase transition
at high baryon densities are discussed.Comment: LaTeX, 23 pages, 7 figures, new references and discussion added,
typos correcte
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