ATLAS Collaboration(Aad, G. et al), Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Fernandez Martinez, P., Ferrer, A., et al. (2015). Search for high-mass diphoton resonances in pp collisions at pffisffi root s=8 TeV with the ATLAS detector. Phys. Rev. D, 92(3), 032004–22pp.
Abstract: This article describes a search for high-mass resonances decaying to a pair of photons using a sample of 20.3 fb(-1) of pp collisions at root s = 8 TeV recorded with the ATLAS detector at the Large Hadron Collider. The data are found to be in agreement with the Standard Model prediction, and limits are reported in the framework of the Randall-Sundrum model. This theory leads to the prediction of graviton states, the lightest of which could be observed at the Large Hadron Collider. A lower limit of 2.66 (1.41) TeV at 95% confidence level is set on the mass of the lightest graviton for couplings of k/(M) over bar (Pl) = 0.1 (0.01).
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Bazeia, D., Losano, L., Olmo, G. J., Rubiera-Garcia, D., & Sanchez-Puente, A. (2015). Classical resolution of black hole singularities in arbitrary dimension. Phys. Rev. D, 92(4), 044018–15pp.
Abstract: A metric-affine approach is employed to study higher-dimensional modified gravity theories involving different powers and contractions of the Ricci tensor. It is shown that the field equations are always second-order, as opposed to the standard metric approach, where this is only achieved for Lagrangians of the Lovelock type. We point out that this property might have relevant implications for the AdS/CFT correspondence in black hole scenarios. We illustrate these aspects by considering the case of Born-Infeld gravity in d dimensions, where we work out exact solutions for electrovacuum configurations. Our results put forward that black hole singularities in arbitrary dimensions can be cured in a purely classical geometric scenario governed by second-order field equations.
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Garcia-Recio, C., Hidalgo-Duque, C., Nieves, J., Salcedo, L. L., & Tolos, L. (2015). Compositeness of the strange, charm, and beauty odd parity Lambda states. Phys. Rev. D, 92(3), 034011–14pp.
Abstract: We study the dependence on the quark mass of the compositeness of the lowest-lying odd parity hyperon states. Thus, we pay attention to Lambda-like states in the strange, charm, and beauty sectors which are dynamically generated using a unitarized meson-baryon model. In the strange sector we use a SU(6) extension of the Weinberg-Tomozawa meson-baryon interaction, and we further implement the heavy-quark spin symmetry to construct the meson-baryon interaction when charmed or beauty hadrons are involved. In the three examined flavor sectors, we obtain two J(P) = 1/2- and one J(P) = 3/2(-) Lambda states. We find that the. states which are bound states (the three Lambda(b)) or narrow resonances [one Lambda(1405) and one Lambda(c)(2595)] are well described as molecular states composed of s-wave meson-baryon pairs. The 1/2(-) wide Lambda(1405) and Lambda(c)(2595) as well as the 3/2(-) Lambda(1520) and Lambda(c)(2625) states display smaller compositeness so they would require new mechanisms, such as d-wave interactions.
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Liang, W. H., Xie, J. J., & Oset, E. (2015). (B)over-bar(0) decay into D-0 and f(0)(500), f(0)(980), a(0)(980), rho and (B)over-bar(s)(0) decay into D-0 and kappa(800), K*(0). Phys. Rev. D, 92(3), 034008–9pp.
Abstract: We make predictions for ratios of branching fractions of (B) over bar (0) decays into D-0 and the scalar mesons f(0)(500), f(0)(980), a(0)(980), plus (B) over bar (0)(s) decay into D-0 and kappa(800). We also compare the pi(+)pi(-) production in the scalar channel with that observed in the rho channel and make predictions for the (B) over bar (0)(s) decay into D-0 and K*(892), comparing the strength of this channel with that of kappa(800) production. The work is based on results of the chiral unitary approach where the scalar resonances are generated from the pseudoscalar-pseudoscalar interaction. Up to an arbitrary normalization, the mass distributions and rates for decays into the scalar resonances are predicted with no free parameters. Comparison with experimental data is done when available.
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Wang, E., Alvarez-Ruso, L., Hayato, Y., Mahn, K., & Nieves, J. (2015). Photon emission in neutral current interactions at the T2K experiment. Phys. Rev. D, 92(5), 053005–8pp.
Abstract: We have applied a microscopic model for single photon emission in neutral current interactions on nucleons and nuclei to determine the number and distributions of such events at the Super-Kamiokande detector, for the flux and beam exposure of the T2K experiment in neutrino mode. These reactions represent an effectively irreducible background in electron-(anti) neutrino appearance measurements aimed at a precise measurement of mixing angle theta(13) and the CP violating phase. We have obtained a total number of photon events that is twice as large as the one from the NEUT event generator (version 5.1.4.2) used in the analysis of T2K data. Detailed comparisons of energy and angular distributions for the nu μand (nu) over bar μfluxes have also been performed.
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