Modern Physics Letters A

We discuss the physical applicability of a model for a class of compact stars, employing Vaidya–Tikekar¹² geometry of space–time. It is shown that the model can generate an equation of state (EOS) very similar to the one obtained by earlier workers for SAX J1808.4-3658 (SAX in short), assumed to be a strange star. The stellar configuration, as described by the model, is shown to be stable under radial perturbations. This may explain why the star SAX is known to be very stable compared to other low mass binary X-ray emitters.

Order-p parasupersymmetric and orthosupersymmetric quantum mechanics are shown to be fully reducible when they are realized in terms of the generators of a generalized deformed oscillator algebra and a ℤ_p+1-grading structure is imposed on the Fock space. The irreducible components provide p + 1 sets of bosonized operators corresponding to both unbroken and broken cases. Such a bosonization is minimal.

The RG flow in the finite-temperature (2 + 1)D Georgi–Glashow model is explored in the regime when the Higgs field is not infinitely heavy, but its mass is rather of the same order of magnitude as the mass of the W-boson. The corrections to the standard RG flow are derived to the leading order in the inverse mass of the Higgs boson. The scaling of the free-energy density in the critical region and the value of the critical temperature of the Berezinsky–Kosterlitz–Thouless (BKT) phase transition are found to be unaffected by the finiteness of the Higgs–boson mass. The evolution of the Higgs mass itself is also investigated and shown to be rather weak, that enables one to treat this parameter as a constant. The same analysis is further performed in the SU(N)-case at N > 2, where the RG invariance is demonstrated to hold only approximately, in a certain sense. Modulo this approximation, the critical behavior of the SU(N)-model turns out to be identical to that of the SU(2)-one.

Recently the evidence of the neutrinoless double β (0νββ) decay has been announced. This means that neutrinos are Majorana particles and their mass hierarchy is forced to certain patterns in the diagonal basis of charged lepton mass matrix. We estimate the magnitude of 0νββ decay in the classification of the neutrino mass hierarchy patterns as Type A, m_1,2 ≪ m₃, Type B, m₁ ~ m₂ ≫ m₃, and Type C, m₁ ~ m₂ ~ m₃, where m_i is the ith generation neutrino absolute mass. The data of 0νββ decay experiment suggest that the neutrino mass hierarchy pattern should be Type B or C. Type B predicts a small magnitude of 0νββ decay which is just edge of the allowed region of experimental value in 95% c.l., where Majorana CP phases should be in a certain parameter region. Type C can induce the suitably large amount of 0νββ decay which is consistent with the experimental data, where overall scale of degenerate neutrino mass plays a crucial role, and its large value can induce the large 0νββ decay in any parameter regions of Majorana CP phases.

The data from Pioneer 10 and 11 shows an anomalous, constant, Doppler frequency drift that can be interpreted as an acceleration directed towards the Sun of a_P = (8.74 ± 1.33) × 10^-8cm/s². Although one can consider a new physical origin for the anomaly, one must first investigate the contributions of the prime candidates, which are systematics generated on board. Here we expand upon previous analyses of thermal systematics. We demonstrate that thermal models put forth so far are not supported by the analyzed data. Possible ways to further investigate the nature of the anomaly are proposed.

We consider the divergences at all levels for the statistical entropy of gravitational, electromagnetic, neutrino and scalar fields on extremal and nonextremal Reissner–Nordström–de Sitter space–time background in terms of the brick-wall model. We find that entropy of spin fields within a region near coinciding horizons has higher divergence than usual. The earlier result that the entropy of spin fields is proportional to scalar one or the horizon area holds only for the thin region near an isolated horizon, since the spin-dependent divergences exist in all other cases.