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Hellmann, C., & Ruiz-Femenia, P. (2013). Non-relativistic pair annihilation of nearly mass degenerate neutralinos and charginos II. P-wave and next-to-next-to-leading order S-wave coefficients. J. High Energy Phys., 08(8), 084–49pp.
Abstract: This paper is a continuation of an earlier work (arXiv:1210.7928) which computed analytically the tree-level annihilation rates of a collection of non-relativistic neutralino and chargino two-particle states in the general MSSM. Here we extend the results by providing the next-to-next-to-leading order corrections to the rates in the non-relativistic expansion in momenta and mass differences, which include leading P-wave effects, in analytic form. The results are a necessary input for the calculation of the Sommerfeld-enhanced dark matter annihilation rates including short-distance corrections at next-to-next-to-leading order in the non-relativistic expansion in the general MSSM with neutralino LSP.
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Emmanuel-Costa, D., Simoes, C., & Tortola, M. (2013). The minimal adjoint-SU (5) x Z(4) GUT model. J. High Energy Phys., 10(10), 054–30pp.
Abstract: An extension of the adjoint SU (5) model with a flavour symmetry based on the Z(4) group is investigated. The Z(4) symmetry is introduced with the aim of leading the up-and down-quark mass matrices to the Nearest-Neighbour-Interaction form. As a consequence of the discrete symmetry embedded in the SU (5) gauge group, the charged lepton mass matrix also gets the same form. Within this model, light neutrinos get their masses through type-I, type-III and one-loop radiative seesaw mechanisms, implemented, respectively, via a singlet, a triplet and an octet from the adjoint fermionic 24 fields. It is demonstrated that the neutrino phenomenology forces the introduction of at least three 24 fermionic multiplets. The symmetry SU (5) x Z(4) allows only two viable zero textures for the effective neutrino mass matrix. It is showed that one texture is only compatible with normal hierarchy and the other with inverted hierarchy in the light neutrino mass spectrum. Finally, it is also demonstrated that Z(4) freezes out the possibility of proton decay through exchange of coloured Higgs triplets at tree-level.
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Cembranos, J. A. R., de la Cruz-Dombriz, A., Gammaldi, V., Lineros, R. A., & Maroto, A. L. (2013). Reliability of Monte Carlo event generators for gamma-ray dark matter searches. J. High Energy Phys., 09(9), 077–21pp.
Abstract: We study the differences in the gamma-ray spectra simulated by four Monte Carlo event generator packages developed in particle physics. Two different versions of PYTHIA and two of HERWIG are analyzed, namely PYTHIA 6.418 and HERWIG 6.5.10 in Fortran and PYTHIA 8.165 and HERWIG 2.6.1 in C++. For all the studied channels, the intrinsic differences between them are shown to be significative and may play an important role in misunderstanding dark matter signals.
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Bueno, P., Galli, P., Meessen, P., & Ortin, T. (2013). Black holes and equivariant charge vectors in N=2, d=4 supergravity. J. High Energy Phys., 09(9), 010–51pp.
Abstract: We extend previous investigations on the construction of extremal supersymmetric and non-supersymmetric solutions in the H-FGK formalism to unconventional solutions with anharmonic terms. We show how the use of fake charge vectors equivariant under duality transformations simplifies and clarifies the task of identification of the attractors of the theory.
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ATLAS Collaboration(Aad, G. et al), Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Fassi, F., Ferrer, A., et al. (2013). Performance of jet substructure techniques for large-R jets in proton-proton collisions at root s=7 TeV using the ATLAS detector. J. High Energy Phys., 09(9), 076–83pp.
Abstract: This paper presents the application of a variety of techniques to study jet substructure. The performance of various modified jet algorithms, or jet grooming techniques, for several jet types and event topologies is investigated for jets with transverse momentum larger than 300 GeV. Properties of jets subjected to the mass-drop filtering, trimming, and pruning algorithms are found to have a reduced sensitivity to multiple proton-proton interactions, are more stable at high luminosity and improve the physics potential of searches for heavy boosted objects. Studies of the expected discrimination power of jet mass and jet substructure observables in searches for new physics are also presented. Event samples enriched in boosted W and Z bosons and top-quark pairs are used to study both the individual jet invariant mass scales and the efficacy of algorithms to tag boosted hadronic objects. The analyses presented use the full 2011 ATLAS dataset, corresponding to an integrated luminosity of 4.7 +/- 0.1 fb(-1) from proton-proton collisions produced by the Large Hadron Collider at a centre-of-mass energy of root s = 7 TeV.
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Hirsch, M., Lineros, R. A., Morisi, S., Palacio, J., Rojas, N., & Valle, J. W. F. (2013). WIMP dark matter as radiative neutrino mass messenger. J. High Energy Phys., 10(10), 149–18pp.
Abstract: The minimal seesaw extension of the Standard SU(3)(c)circle times SU(2)(L)circle times U(1)(Y) Model requires two electroweak singlet fermions in order to accommodate the neutrino oscillation parameters at tree level. Here we consider a next to minimal extension where light neutrino masses are generated radiatively by two electroweak fermions: one singlet and one triplet under SU(2)(L). These should be odd under a parity symmetry and their mixing gives rise to a stable weakly interactive massive particle (WIMP) dark matter candidate. For mass in the GeV-TeV range, it reproduces the correct relic density, and provides an observable signal in nuclear recoil direct detection experiments. The fermion triplet component of the dark matter has gauge interactions, making it also detectable at present and near future collider experiments.
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Dehnadi, B., Hoang, A. H., Mateu, V., & Zebarjad, S. M. (2013). Charm mass determination from QCD charmonium sum rules at order alpha(3)(s). J. High Energy Phys., 09(9), 103–56pp.
Abstract: We determine the (MS) over bar charm quark mass from a charmonium QCD sum rules analysis. On the theoretical side we use input from perturbation theory at O (alpha(3)(s)). Improvements with respect to previous O (alpha(3)(s)) analyses include (1) an account of all available e(+)e(-) hadronic cross section data and (2) a thorough analysis of perturbative uncertainties. Using a data clustering method to combine hadronic cross section data sets from di ff erent measurements we demonstrate that using all available experimental data up to c. m. energies of 10 : 538 GeV allows for determinations of experimental moments and their correlations with small errors and that there is no need to rely on theoretical input above the charmonium resonances. We also show that good convergence properties of the perturbative series for the theoretical sum rule moments need to be considered with some care when extracting the charm mass and demonstrate how to set up a suitable set of scale variations to obtain a proper estimate of the perturbative uncertainty. As the fi nal outcome of our analysis we obtain (m(c)) over bar((m(c)) over bar) = 1 : 282 +/- (0.009)(stat) +/- (0.009)(syst) +/- (0.019)(pert) +/- (0.010)(alpha s) +/- (0.002)(< GG >) GeV. The perturbative error is an order of magnitude larger than the one obtained in previous O (alpha(3)(s)) sum rule analyses.
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ATLAS Collaboration(Aad, G. et al), Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Fassi, F., Ferrer, A., et al. (2013). Measurement of the production cross section of jets in association with a Z boson in pp collisions at root s=7 TeV with the ATLAS detector. J. High Energy Phys., 07(7), 032–51pp.
Abstract: Measurements of the production of jets of particles in association with a Z boson in pp collisions at root s = 7 TeV are presented, using data corresponding to an integrated luminosity of 4.6 fb(-1) collected by the ATLAS experiment at the Large Hadron Collider. Inclusive and differential jet cross sections in Z events, with Z decaying into electron or muon pairs, are measured for jets with transverse momentum p(T) > 30 GeV and rapidity vertical bar y vertical bar < 4.4. The results are compared to next-to-leading-order perturbative QCD calculations, and to predictions from different Monte Carlo generators based on leading-order and next-to-leading-order matrix elements supplemented by parton showers.
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LHCb Collaboration(Aaij, R. et al), Oyanguren, A., & Ruiz Valls, P. (2013). Differential branching fraction and angular analysis of the decay B-s(0) -> phi mu(+)mu(-). J. High Energy Phys., 07(7), 084–18pp.
Abstract: The determination of the differential branching fraction and the first angular analysis of the decay B-s(0) -> phi mu(+)mu(-) are presented using data, corresponding to an integrated luminosity of 1.0 fb(-1), collected by the LHCb experiment at root s = 7 TeV. The differential branching fraction is determined in bins of q(2), the invariant dimuon mass squared. Integration over the full q2 range yields a total branching fraction of B(B-s(0) -> phi mu(+)mu(-)) = (7.07(-0.59)(+0.64) +/- 0.17 +/- 0.71) x 10(-7), where the first uncertainty is statistical, the second systematic, and the third originates from the branching fraction of the normalisation channel. An angular analysis is performed to determine the angular observables F-L, S-3, A(6), and A(9). The observables are consistent with Standard Model expectations.
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Celis, A., Ilisie, V., & Pich, A. (2013). LHC constraints on two-Higgs doublet models. J. High Energy Phys., 07(7), 053–44pp.
Abstract: A new Higgs-like boson with mass around 126 GeV has recently been discovered at the LHC. The available data on this new particle is analyzed within the context of two-Higgs doublet models without tree-level flavour-changing neutral currents. Keeping the generic Yukawa structure of the Aligned Two-Higgs Doublet Model framework, we study the implications of the LHC data on the allowed scalar spectrum. We analyze both the CP-violating and CP-conserving cases, and a few particular limits with a reduced number of free parameters, such as the usual models based on discrete Z(2) symmetries.
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