Modern Physics Letters A

This is an invited summary of a seminar talk given at various institutions in the United States and Canada. After a brief introduction, a review of the minimal R-symmetric supersymmetric standard model is given, and the benefits to the flavor sector are discussed. R-symmetric gauge mediation is an attempt to realize this model using metastable supersymmetry breaking techniques. Sample low energy spectra are presented and tuning is discussed. Various other phenomenological results are summarized.

The phase structure of neutral two-flavor quark matter at nonzero temperature is studied. Our analysis is performed within the framework of a gauged Nambu–Jona-Lasinio model and the mean-field approximation. We compute the free energy of the gluonic phase (gluonic cylindrical phase II) in a self-consistent manner and investigate the phase transition from the gluonic phase to the 2SC/g2SC/NQ phases. We briefly consider the phase diagram in the plane of coupling strength versus temperature and discuss the mixed phase consisting of the normal quark and 2SC phases.

We show that any analytic f(R)-gravity model, in the metric approach, presents a weak field limit where the standard Newtonian potential is corrected by a Yukawa-like term. This general result has never been pointed out but often derived for some particular theories. This means that only f(R) = R allows to recover the standard Newton potential while this is not the case for other relativistic theories of gravity. Some considerations on the physical consequences of such a general solution are addressed.

We investigate the possibility that the observed behavior of test particles outside galaxies, which is usually explained by assuming the presence of dark matter, is the result of the dynamical evolution of particles in higher dimensional spacetimes. Hence, dark matter may be a direct consequence of the presence of an extra force, generated by the presence of extra dimensions, which modifies the dynamic law of motion, but does not change the intrinsic properties of the particles, like, for example, the mass (inertia). We discuss in some detail several possible particular forms for the extra force, and the acceleration law of the particles is derived. Therefore, the constancy of the galactic rotation curves may be considered as an empirical evidence for the existence of the extra dimensions.

We consider a variable modified Chaplygin gas (VMCG) model with unified dark energy and dark matter. Some cosmological quantities are studied, such as the state parameter of dark energy w_de, the fractional energy densities Ω_i (i respectively denotes baryons, dark matter, dark energy), the deceleration parameter q and the growth index f. By analysis, we find that the state parameter of dark energy can cross the phantom divide w_Λ = -1, the behavior of VMCG is similar to radiation in the early time and will be quinessence model in the future. Therefore the universe will not end up with Big Rip.

Based on previous studies deriving the chiral Lagrangian for pseudo scalar mesons from the first principle of QCD in the path integral formalism, we derive the electroweak chiral Lagrangian and dynamically compute all its coefficients from the one family technicolor model. The numerical results of the p⁴ order coefficients obtained in this paper are proportional to the technicolor number N_TC and the technifermion number N_TF, which agrees with the arguments in previous works, and which confirms the reliability of this dynamical computation.

We have studied here electroweak symmetry breaking and baryogenesis from the viewpoint of topological mass generation through chiral anomaly. It is shown that the SU(2) gauge symmetry of the electroweak theory breaks in two stages. In the final stage we have Z-strings produced at the phase transition. We have also studied the problem of baryogenesis in this formalism and the ratio of the baryon–antibaryon is found to be in good agreement with the observed value.