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Sakai, S., Oset, E., & Liang, W. H. (2017). Abnormal isospin violation and a(0) – f(0) mixing in the D-s(+) -> pi(+) pi(0)a(0)(980)(f(0)(980)) reactions. Phys. Rev. D, 96(7), 074025–11pp.
Abstract: We have chosen the reactions D-s(+) -> pi(+) pi(0)a(0)(980)(f(0)(980)) investigating the isospin violating channel D-s(+) -> pi+ pi(0)f(0)(980). The reaction was chosen because by varying the pi(0)a(0)(980)(f(0)(980)) invariant mass one goes through the peak of a triangle singularity emerging from D-s(+) -> pi(K) over bar *K, followed by (K) over bar* -> (K) over bar pi(0) and the further merging of K (K) over bar to produce the a(0)(980) or f(0)(980). We found that the amount of isospin violation had its peak precisely at the value of the pi(0)a(0)(980)(f(0)(980)) invariant mass where the singularity has its maximum, stressing the role of the triangle singularities as a factor to enhance the mixing of the f(0)(980) and a(0)(980) resonances. We calculate absolute rates for the reactions and show that they are within present measurable range. The measurement of these reactions would bring further information into the role of triangle singularities in isospin violation and the a(0) – f(0) mixing, in particular, and shed further light into the nature of the low energy scalar mesons.
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Dias, J. M., Debastiani, V. R., Roca, L., Sakai, S., & Oset, E. (2017). Binding of the BD(D)over-bar and BDD systems. Phys. Rev. D, 96(9), 094007–6pp.
Abstract: We study theoretically the BD (D) over bar and BDD systems to see if they allow for possible bound or resonant states. The three-body interaction is evaluated implementing the fixed center approximation to the Faddeev equations which considers the interaction of a D or (D) over bar particle with the components of a BD cluster, previously proved to form a bound state. We find an I(J(P)) = 1/2(0(-)) bound state for the BD (D) over bar system at an energy around 8925-8985 MeV within uncertainties, which would correspond to a bottom hidden-charm meson. In contrast, for the BDD system, which would be bottom double-charm and hence manifestly exotic, we have found hints of a bound state in the energy region 8935-8985 MeV, but the results are not stable under the uncertainties of the model, and we cannot assure, nor rule out, the possibility of a BDD three-body state.
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Menchon, C. C., Olmo, G. J., & Rubiera-Garcia, D. (2017). Nonsingular black holes, wormholes, and de Sitter cores from anisotropic fluids. Phys. Rev. D, 96(10), 104028–16pp.
Abstract: We study Born-Infeld gravity coupled to an anisotropic fluid in a static, spherically symmetric background. The free function characterizing the fluid is selected on the following grounds: i) recovery of the Reissner-Nordstrom solution of General Relativity at large distances, ii) fulfillment of classical energy conditions, and iii) inclusion of models of nonlinear electrodynamics as particular examples. Four branches of solutions are obtained, depending on the signs of two parameters on the gravity and matter sectors. On each branch, we discuss in detail the modifications on the innermost region of the corresponding solutions, which provides a plethora of configurations, including nonsingular black holes and naked objects, wormholes, and de Sitter cores. The regular character of these configurations is discussed according to the completeness of geodesics and the behavior of curvature scalars.
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T2K Collaboration(Abe, K. et al), Cervera-Villanueva, A., Izmaylov, A., & Novella, P. (2017). Measurement of neutrino and antineutrino oscillations by the T2K experiment including a new additional sample of nu(e) interactions at the far detector. Phys. Rev. D, 96(9), 092006–49pp.
Abstract: The T2K experiment reports an updated analysis of neutrino and antineutrino oscillations in appearance and disappearance channels. A sample of electron neutrino candidates at Super-Kamiokande in which a pion decay has been tagged is added to the four single-ring samples used in previous T2K oscillation analyses. Through combined analyses of these five samples, simultaneous measurements of four oscillation parameters, vertical bar Delta m(32)(2)vertical bar, sin(2) theta(23), sin(2) theta(13), and delta(CP) and of the mass ordering are made. A set of studies of simulated data indicates that the sensitivity to the oscillation parameters is not limited by neutrino interaction model uncertainty. Multiple oscillation analyses are performed, and frequentist and Bayesian intervals are presented for combinations of the oscillation parameters with and without the inclusion of reactor constraints on sin(2) theta(13). When combined with reactor measurements, the hypothesis of CP conservation (delta(CP) = 0 or pi) is excluded at 90% confidence level. The 90% confidence region for delta(CP) is [-2.95, -0.44] ([-1.47, -1.27]) for normal (inverted) ordering. The central values and 68% confidence intervals for the other oscillation parameters for normal (inverted) ordering are Delta m(32)(2) = 2.54 +/- 0.08(2.51 +/- 0.08) x 10(-3) eV(2)/c(4) and sin(2) theta(23) = 0.55(-0.09)(+0.005) (0.55(-0.08)(+0.05)), compatible with maximal mixing. In the Bayesian analysis, the data weakly prefer normal ordering (Bayes factor 3.7) and the upper octant for sin(2) theta(23) (Bayes factor 2.4).
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Hiller Blin, A. N. (2017). Systematic study of octet-baryon electromagnetic form factors in covariant chiral perturbation theory. Phys. Rev. D, 96(9), 093008–19pp.
Abstract: We perform a complete and systematic calculation of the octet-baryon form factors within the fully covariant approach of SU(3) chiral perturbation theory at O(p(3)). We use the extended on-mass shell renormalization scheme and include explicitly the vector mesons and the spin-3/2 decuplet intermediate states. Comparing these predictions with data including magnetic moments, charges, and magnetic radii, we determine the unknown low-energy constants and give predictions for yet unmeasured observables, such as the magnetic moment of the Sigma(0) and the charge and magnetic radii of the hyperons.
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