1,861 research outputs found
Primordial star formation triggered by UV photons from UHECR
The presence of ultra-high energy cosmic rays in the universe in the
pre-ionization epoch enhances significantly H kinetics in virialized halos.
It results in more efficient radiative cooling and decreases the lower mass
limit of the first star-forming systems. Consequently, the fraction of baryons
contained in the first luminous objects and their contribution to the
reionization of the universe can significantly increase in comparison with the
standard scenario.Comment: 5 pages, 3 figures, accepted in A&
Higher-Spin Gauge Interactions for Matter Fields in Two Dimensions
We formulate a new model which describes higher-spin gauge interactions for
matter fields in two dimensions. This model is a higher-spin generalization of
d2 gravity and turns out to be integrable. No vanishing higher-spin current
conditions are imposed on the matter fields.Comment: LaTex, 10 pages, no figures, to be published in Phys. Lett.
Generalized Toda Field Theories
In this paper we introduce a unified approach to Toda field theories which
allows us to formulate the classes of , and models as unique
models involving an arbitrary continuous parameter . For certain values of
, the model describes the standard Toda theories. For other values of
it defines a class of models that involve infinitely many fields. These
models interpolate between the various standard Toda field theories. They are
conformally invariant and possess infinitely many conserved higher-spin
currents thus making them candidates for a new set of integrable systems. A
general construction is performed, which can effectively be used for the
derivation of explicit forms of particular higher-spin currents. We also study
the currents in a different representation in which they are linear in the
dynamical variables having, however, a non-linear Poisson bracket algebra. An
explicit formula for this Poisson structure is found.Comment: 35 pages, latex, no figures; submitted to Nucl. Phys.
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