788 research outputs found
Spontaneous parity violation in extreme conditions: an effective lagrangian analysis
We investigate how large baryon densities (and possibly high temperatures)
may induce spontaneous parity violation in the composite meson sector of
vector-like gauge theory (presumably QCD or techni-QCD) . The analysis at
intermediate energy scales is done by using an extended -model
lagrangian that includes two scalar and two pseudoscalar multiplets and
fulfills low-energy constraints for vector-like gauge theories. We elaborate on
a novel mechanism of parity breaking based on the interplay between lightest
and heavier meson condensates, which therefore cannot be realized in the
simplest model. The results are relevant for an idealized homogeneous
and infinite nuclear (quark or techniquark) matter where the influence of
density can be examined with the help of a constant chemical potential. The
model is able to describe satisfactorily the first-order phase transition to
stable nuclear matter, and predicts a second-order phase transition to a state
where parity is spontaneously broken. We argue that the parity breaking
phenomenon is quite generic when a large enough chemical potential is present.
Current quark masses are explicitly taken into account in this work and shown
not to change the general conclusions.Comment: 24 pages, substantial revisio
Searching for P- and CP-odd effects in heavy ion collisions
In this talk we will summarize the main results from our recent work
concerning the possibility that a new metastable phase occurs in some heavy ion
collisions (HIC). This phase would be characterized by the breaking of two
characteristic symmetries of strong interactions; namely P and CP. We
investigate the experimental consequences of parity breaking in such a
situation and propose suitable observables to elucidate the presence this
phenomenon.Comment: Talk presented at the XI Conference on Quark Confinement and Hadron
Spectrum, Saint Petersburg, September 201
Stellar matter with pseudoscalar condensates
In this work we consider how the appearance of gradients of pseudoscalar
condensates in dense systems may possibly influence the transport properties of
photons in such a medium as well as other thermodynamic characteristics. We
adopt the hypothesis that in regions where the pseudoscalar density gradient is
large the properties of photons and fermions are governed by the usual
lagrangian extended with a Chern-Simons interaction for photons and a constant
axial field for fermions. We find that these new pieces in the lagrangian
produce non-trivial reflection coefficients both for photons and fermions when
entering or leaving a region where the pseudoscalar has a non-zero gradient. A
varying pseudoscalar density may also lead to instability of some fermion and
boson modes and modify some properties of the Fermi sea. We speculate that some
of these modifications could influence the cooling rate of stellar matter (for
instance in compact stars) and have other observable consequences. While
quantitative results may depend on precise astrophysical details most of the
consequences are quite universal and consideration should be given to this
possibility.Comment: 14 pages,6 figures, the version to be publishe
Classical Integrable 2-dim Models Inspired by SUSY Quantum Mechanics
A class of integrable 2-dim classical systems with integrals of motion of
fourth order in momenta is obtained from the quantum analogues with the help of
deformed SUSY algebra. With similar technique a new class of potentials
connected with Lax method is found which provides the integrability of
corresponding 2-dim hamiltonian systems. In addition, some integrable 2-dim
systems with potentials expressed in elliptic functions are explored.Comment: 19 pages, LaTeX, final version to be published in J.Phys.
Factorization of non-linear supersymmetry in one-dimensional Quantum Mechanics. II: proofs of theorems on reducibility
In this paper, we continue to study factorization of supersymmetric (SUSY)
transformations in one-dimensional Quantum Mechanics into chains of elementary
Darboux transformations with nonsingular coefficients. We define the class of
potentials that are invariant under the Darboux - Crum transformations and
prove a number of lemmas and theorems substantiating the formulated formerly
conjectures on reducibility of differential operators for spectral equivalence
transformations. Analysis of the general case is performed with all the
necessary proofs.Comment: 13 page
Dimensional structural constants from chiral and conformal bosonization of QCD
We derive the dimensional non-perturbative part of the QCD effective action
for scalar and pseudoscalar meson fields by means of chiral and conformal
bosonization. The related structural coupling constants L_5 and L_8 of the
chiral lagrangian are estimated using general relations which are valid in a
variety of chiral bosonization models without explicit reference to model
parameters. The asymptotics for large scalar fields in QCD is elaborated, and
model-independent constraints on dimensional coupling constants of the
effective meson lagrangian are evaluated. We determine also the interaction
between scalar quarkonium and the gluon density and obtain the scalar
glueball-quarkonium potential.Comment: 21 pages, LaTe
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