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de Azcarraga, J. A., & Izquierdo, J. M. (2012). D=3 (p, q)-Poincare supergravities from Lie algebra expansions. Nucl. Phys. B, 854(1), 276–291.
Abstract: We use the expansion of superalgebras procedure (summarized in the text) to derive Chem-Simons (CS) actions for the (p, q)-Poincare supergravities in three-dimensional spacetimes. After deriving the action for the (p, 0)-Poincare supergravity as a CS theory for the expansion osp(p vertical bar 2: R)(2, 1) of osp(p vertical bar 2: R), we find the general (p, q)-Poincare superalgebras and their associated D = 3 supergravity actions as CS gauge theories from an expansion of the simple osp(p + q vertical bar 2, R) superalgebras, namely osp(p + q vertical bar 2, R)(2, 1, 2).
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Herrero-Garcia, J., Nebot, M., Rius, N., & Santamaria, A. (2014). The Zee-Babu model revisited in the light of new data. Nucl. Phys. B, 885, 542–570.
Abstract: We update previous analyses of the Zee-Babu model in the light of new data, e.g., the mixing angle On, the rare decay μ-> e gamma and the LHC results. We also analyze the possibility of accommodating the deviations in Gamma (H -> gamma gamma) hinted by the LHC experiments, and the stability of the scalar potential. We find that neutrino oscillation data and low energy constraints are still compatible with masses of the extra charged scalars accessible to LHC. Moreover, if any of them is discovered, the model can be falsified by combining the information on the singly and doubly charged scalar decay modes with neutrino data. Conversely, if the neutrino spectrum is found to be inverted and the CP phase delta is quite different from pi, the masses of the charged scalars will be well outside the LHC reach.
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Kittel, O., & Pilaftsis, A. (2012). CP violation in correlated production and decay of unstable particles. Nucl. Phys. B, 856(3), 682–697.
Abstract: We study resonant CP-violating Einstein-Podolsky-Rosen correlations that may take place in the production and decay of unstable scalar particles at high-energy colliders. We show that as a consequence of unitarity and CPT invariance of the S-matrix, in 2 -> 2 scatterings mediated by mixed scalar particles, at least three linearly independent decay matrices associated with the unstable scalar states are needed to obtain non-zero CP-odd observables that are also odd under C-conjugation. Instead, for the correlated production and decay of two unstable particle systems in 2 -> 4 processes, we find that only two independent decay matrices are sufficient to induce a net non-vanishing CP-violating phenomenon. As an application of this theorem, we present numerical estimates of CP asymmetries for the correlated production and decay of supersymmetric scalar top anti-top pairs at the LHC, and demonstrate that these could reach values of order one. As a byproduct of our analysis, we develop a novel spinorial trace technique, which enables us to efficiently evaluate lengthy expressions of squared amplitudes describing the resonant scalar transitions.
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de Azcarraga, J. A., & Izquierdo, J. M. (2014). Minimal D=4 supergravity from the superMaxwell algebra. Nucl. Phys. B, 885, 34–45.
Abstract: We show that the first-order D = 4, N = 1 pure supergravity lagrangian four-form can be obtained geometrically as a quadratic expression in the curvatures of the Maxwell superalgebra. This is achieved by noticing that the relative coefficient between the two terms of the lagrangian that makes the action locally supersymmetric also determines trivial field equations for the gauge fields associated with the extra generators of the Maxwell superalgebra. Along the way, a convenient geometric procedure to check the local supersymmetry of a class of lagrangians is developed.
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Ludl, P. O., Morisi, S., & Peinado, E. (2012). The reactor mixing angle and CP violation with two texture zeros in the light of T2K. Nucl. Phys. B, 857(3), 411–423.
Abstract: We reconsider the phenomenological implications of two texture zeros in symmetric neutrino mass matrices in the light of the recent T2K results for the reactor angle and the new global analysis which gives also best fit values for the Dirac CP phase delta. The most important results of the analysis are: Among the viable cases classified by Frampton etal, only A(1) and A(2) predict theta(13) to be different from zero at 3 sigma. Furthermore these two cases are compatible only with a normal mass spectrum in the allowed region for the reactor angle. At the best fit value A(1) and A(2) predict 0.024 >= sin(2)theta(13) >= 0.012 and 0.014 <= sin(2)theta(13) <= 0.032, respectively, where the bounds on the right and the left correspond to cos delta = -1 and cos delta = 1, respectively. The cases B-1, B-2, B-3 and B-4 predict nearly maximal CP violation, i.e. cos delta approximate to 0.
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Bandos, I. A., de Azcarraga, J. A., & Meliveo, C. (2011). Extended supersymmetry in massless conformal higher spin theory. Nucl. Phys. B, 853(3), 760–776.
Abstract: We propose superfield equations in tensorial N-extended superspaces to describe the N = 2,4,8 supersymmetric generalizations of free conformal higher spin theories. These can be obtained by quantizing a superparticle model in N-extended tensorial superspace. The N-extended higher spin supermultiplets just contain scalar and 'spinor' fields in tensorial space so that, in contrast with the standard (super)space approach, no nontrivial generalizations of the Maxwell or Einstein equations to tensorial space appear when N > 2. For N = 4,8, the higher spin-tensorial components of the extended tensorial superfields are expressed through additional scalar and spinor fields in tensorial space which obey the same free higher spin equations, but that are axion-like in the sense that they possess Peccei-Quinn-like symmetries.
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Chachamis, G., Hentschinski, M., Madrigal Martinez, J. D., & Sabio Vera, A. (2013). Gluon Regge trajectory at two loops from Lipatov's high energy effective action. Nucl. Phys. B, 876(2), 453–472.
Abstract: We present the derivation of the two-loop gluon Regge trajectory using Lipatov's high energy effective action and a direct evaluation of Feynman diagrams. Using a gauge invariant regularization of high energy divergences by deforming the light-cone vectors of the effective action, we determine the two-loop self-energy of the reggeized gluon, after computing the master integrals involved using the Mellin-Barnes representations technique. The self-energy is further matched to QCD through a recently proposed subtraction prescription. The Regge trajectory of the gluon is then defined through renormalization of the reggeized gluon propagator with respect to high energy divergences. Our result is in agreement with previous computations in the literature, providing a non-trivial test of the effective action and the proposed subtraction and renormalization framework.
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NOMAD Collaboration(Samoylov, O. et al), Cervera-Villanueva, A., Gomez-Cadenas, J. J., & Hernando, J. (2013). A precision measurement of charm dimuon production in neutrino interactions from the NOMAD experiment. Nucl. Phys. B, 876(2), 339–375.
Abstract: We present our new measurement of the cross-section for charm dimuon production in neutrino iron interactions based upon the full statistics collected by the NOMAD experiment. After background subtraction we observe 15 344 charm dimuon events, providing the largest sample currently available. The analysis exploits the large inclusive charged current sample – about 9 x 10(6) events after all analysis cuts – and the high resolution NOMAD detector to constrain the total systematic uncertainty on the ratio of charm dimuon to inclusive Charged Current (CC) cross-sections to similar to 2%. We also perform a fit to the NOMAD data to extract the charm production parameters and the strange quark sea content of the nucleon within the NLO QCD approximation. We obtain a value of m(c)(m(c)) = 1.159 +/- 0.075 GeV/c(2) for the running mass of the charm quark in the (MS) over bar scheme and a strange quark sea suppression factor of kappa(s) = 0.591 +/- 0.019 at Q(2) = 20 GeV2/c(2).
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Bernabeu, J., Di Domenico, A., & Villanueva-Perez, P. (2013). Direct test of time reversal symmetry in the entangled neutral kaon system at a phi-factory. Nucl. Phys. B, 868(1), 102–119.
Abstract: We present a novel method to perform a direct T (time reversal) symmetry test in the neutral kaon system, independent of any CP and/or CPT symmetry tests. This is based on the comparison of suitable transition probabilities, where the required interchange of in <-> out states for a given process is obtained exploiting the Einstein-Podolski-Rosen correlations of neutral kaon pairs produced at a phi-factory. In the time distribution between the two decays, we compare a reference transition like the one defined by the time-ordered decays (l(-), pi pi) with the T-conjugated one defined by (3 pi(0), l(+)). With the use of this and other T-conjugated comparisons, the KLOE-2 experiment at DA Phi NE could make a statistically significant test.
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Carrasco, N., Deuzeman, A., Dimopoulos, P., Frezzotti, R., Gimenez, V., Herdoiza, G., et al. (2014). Up, down, strange and charm quark masses with N-f=2+1+1 twisted mass lattice QCD. Nucl. Phys. B, 887, 19–68.
Abstract: We present a lattice QCD calculation of the up, down, strange and charm quark masses performed using the gauge configurations produced by the European Twisted Mass Collaboration with N-f = 2 + 1 + 1 dynamical quarks, which include in the sea, besides two light mass degenerate quarks, also the strange and charm quarks with masses close to their physical values. The simulations are based on a unitary setup for the two light quarks and on a mixed action approach for the strange and charm quarks. The analysis uses data at three values of the lattice spacing and pion masses in the range 210-450 MeV, allowing for accurate continuum limit and controlled chiral extrapolation. The quark mass renormalization is carried out non-perturbatively using the RI'-MOM method. The results for the quark masses converted to the (MS) over bar scheme are: m(ud) (2 GeV) = 3.70(17) MeV, m(s)(2 GeV) = 99.6(4.3) MeV and m(c)(m(c)) = 1.348(46) GeV. We obtain also the quark mass ratios m(s)/m(ud) = 26.66(32) and m(c)/m(s) = 11.62(16). By studying the mass splitting between the neutral and charged kaons and using available lattice results for the electromagnetic contributions, we evaluate m(u)/m(d) = 0.470(56), leading to m(u) = 2.36(24) MeV and m(d) = 5.03(26) MeV.
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