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Garzon, E. J., Molina, R., Hosaka, A., & Oset, E. (2014). Strategies for an accurate determination of the X(3872) energy from QCD lattice simulations. Phys. Rev. D, 89(1), 014504–9pp.
Abstract: We develop a method to determine accurately the binding energy of the X( 3872) from lattice data for the D (D) over bar* interaction. We show that, because of the small difference between the neutral and charged components of the X( 3872), it is necessary to differentiate them in the energy levels of the lattice spectrum if one wishes to have a precise determination of the the binding energy of the X( 3872). The analysis of the data requires the use of coupled channels. Depending on the number of levels available and the size of the box, we determine the precision needed in the lattice energies to finally obtain a desired accuracy in the binding energy.
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Juste, A., Mantry, S., Mitov, A., Penin, A., Skands, P., Varnes, E., et al. (2014). Determination of the top quark mass circa 2013: methods, subtleties, perspectives. Eur. Phys. J. C, 74(10), 3119–14pp.
Abstract: We present an up-to-date overview of the problem of top quark mass determination. We assess the need for precision in the top mass extraction in the LHC era together with the main theoretical and experimental issues arising in precision top mass determination. We collect and document existing results on top mass determination at hadron colliders and map the prospects for future precision top mass determination at e(+)e(-) colliders. We present a collection of estimates for the ultimate precision of various methods for top quark mass extraction at the LHC.
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Campanario, F., Rauch, M., & Sapeta, S. (2014). W+W- production at high transverse momenta beyond NLO. Nucl. Phys. B, 879, 65–79.
Abstract: Pair production of W gauge bosons is an important process at the LHC entering many experimental analyses, both as background in new-physics searches or Higgs measurements and as signal in precision studies and tests of the Standard Model. Therefore, accurate predictions for this class of processes are of great interest in order to exploit the full potential of LHC measurements. We use the LoopSim method to combine NLO QCD results for WW and WW + jet, as well as the loop-squared gluon-fusion contribution, to obtain approximate NNLO predictions for WW production. The cross sections are calculated with VBFNLO and include leptonic decays of the W bosons as well as finite-width and off-shell effects. We find that the size of the additional corrections beyond NLO can be significant and well outside of the NLO error bands given by renormalization and factorization scale variation. Applying a jet veto, we observe further negative corrections at NNLO. which we relate to the presence of large Sudakov logarithms.
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Campanario, F., Kaiser, N., & Zeppenfeld, D. (2014). W gamma production in vector boson fusion at NLO in QCD. Phys. Rev. D, 89(1), 014009–5pp.
Abstract: The next-to-leading order QCD corrections to W-+/-gamma. production in association with two jets via vector boson fusion are calculated, including the leptonic decay of the W with full off-shell effects and spin correlations. The process lends itself to a test of quartic gauge couplings. The next-to-leading order corrections reduce the scale uncertainty significantly and show a nontrivial phase space dependence.
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Xie, J. J., Wang, E., & Nieves, J. (2014). Re-analysis of the A(1520) photoproduction reaction. Phys. Rev. C, 89(1), 015203–10pp.
Abstract: Based on previous studies that support the important role of the N*(2120)D-13 resonance in the gamma p -> K+ A(1520) reaction, we make a re-analysis of this A(1520) photoproduction reaction taking into account the recent CLAS differential cross-section data. In addition to the contact, t-channel (K) over bar exchange, s-channel nucleon pole, and N*(2120) [previously called N*(2080)] resonance contributions, which have been considered in previous works, we also study the u-channel A(1115) hyperon pole term. The latter mechanism has always been ignored in all theoretical analysis, which has mostly relied on the very forward K+ angular LEPS data. It is shown that when the contributions from the N*(2120) resonance and the A(1115) hyperon are taken into account, both the new CLAS and the previous LEPS data can be simultaneously described. We also show that the contribution from the u-channel A(1115) pole term produces an enhancement for large K+ angles, and it becomes more and more relevant as the photon energy increases, being essential to describe the CLAS differential cross sections at backward angles. Furthermore, we find that the new CLAS data also favor the existence of the N*(2120) resonance and that these measurements can be used to further constrain its properties.
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Armillis, R., Lazarides, G., & Pallis, C. (2014). Inflation, leptogenesis, and Yukawa quasiunification within a supersymmetric left-right model. Phys. Rev. D, 89(6), 065032–22pp.
Abstract: A simple extension of the minimal left-right symmetric supersymmetric grand unified theory model is constructed by adding two pairs of superfields. This naturally violates the partial Yukawa unification predicted by the minimal model. After including supergravity corrections, we find that this extended model naturally supports hilltop F-term hybrid inflation along its trivial inflationary path with only a very mild tuning of the initial conditions. With a convenient choice of signs of the terms in the Kahler potential, we can reconcile the inflationary scale with the supersymmetric grand unified theory scale. All the current data on the inflationary observables are readily reproduced. Inflation is followed by nonthermal leptogenesis via the decay of the right-handed neutrinos emerging from the decay of the inflaton, and any possible washout of the lepton asymmetry is avoided thanks to the violation of partial Yukawa unification. The extra superfields also assist us in reducing the reheat temperature so as to satisfy the gravitino constraint. The observed baryon asymmetry of the universe is naturally reproduced consistently with the neutrino oscillation parameters.
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Celis, A., Cirigliano, V., & Passemar, E. (2014). Lepton flavor violation in the Higgs sector and the role of hadronic tau-lepton decays. Phys. Rev. D, 89(1), 013008–19pp.
Abstract: It has been pointed out recently that current low-energy constraints still allow for sizable flavor-changing decay rates of the 125 GeV boson into leptons, h -> tau l (l = e, mu). In this work we discuss the role of hadronic tau-lepton decays in probing lepton flavor violating couplings in the Higgs sector. At low energy, the effective Higgs coupling to gluons induced by heavy quarks contributes to hadronic tau decays, establishing a direct connection with the relevant process at the LHC, pp(gg) -> h -> tau l. Semileptonic transitions like tau -> l pi pi are sensitive to flavor-changing scalar couplings, while decays such as tau -> l eta((l)) probe pseudoscalar couplings, thus providing a useful low-energy handle to disentangle possible Higgs flavor violating signals at the LHC. As part of our analysis, we provide an appropriate description of all the relevant hadronic matrix elements needed to describe Higgs mediated tau -> pi pi transitions, improving over previous treatments in the literature.
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Barenboim, G., Chun, E. J., & Lee, H. M. (2014). Coleman-Weinberg inflation in light of Planck. Phys. Lett. B, 730, 81–88.
Abstract: We revisit a single field inflationary model based on Coleman-Weinberg potentials. We show that in small field Coleman-Weinberg inflation, the observed amplitude of perturbations needs an extremely small quartic coupling of the inflaton, which might be a signature of radiative origin. However, the spectral index obtained in a standard cosmological scenario turns out to be outside the 2 sigma region of the Planck data. When a non-standard cosmological framework is invoked, such as brane-world cosmology in the Randall-Sundrum model, the spectral index can be made consistent with Planck data within la, courtesy of the modification in the evolution of the Hubble parameter in such a scheme. We also show that the required inflaton quartic coupling as well as a phenomenologically viable B – L symmetry breaking together with a natural electroweak symmetry breaking can arise dynamically in a generalized B – L extension of the Standard Model where the full potential is assumed to vanish at a high scale.
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Mantovani Sarti, V., & Vento, V. (2014). The half-skyrmion phase in a chiral-quark model. Phys. Lett. B, 728, 323–327.
Abstract: The Chiral Dilaton Model, where baryons arise as non-topological solitons built from the interaction of quarks and chiral mesons, shows in the high density low temperature regime a two phase scenario in the nuclear matter phase diagram. Dense soliton matter described by the Wigner-Seitz approximation generates a periodic potential in terms of the sigma and pion fields that leads to the formation of a band structure. The analysis up to three times nuclear matter density shows that soliton matter undergoes two separate phase transitions: a delocalization of the baryon number density leading to B = 1/2 structures, as in skyrmion matter, at moderate densities, and quark deconfinement at larger densities. This description fits well into the so-called quarkyonic phase where, before deconfinement, nuclear matter should undergo structural changes involving the restoration of fundamental symmetries of QCD.
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Jung, M., & Pich, A. (2014). Electric dipole moments in two-Higgs-doublet models. J. High Energy Phys., 04(4), 076–42pp.
Abstract: Electric dipole moments are extremely sensitive probes for additional sources of CP violation in new physics models. Specifically, they have been argued in the past to exclude new CP-violating phases in two-Higgs-doublet models. Since recently models including such phases have been discussed widely, we revisit the available constraints in the presence of mechanisms which are typically invoked to evade flavour-changing neutral currents. To that aim, we start by assessing the necessary calculations on the hadronic, nuclear and atomic/molecular level, deriving expressions with conservative error estimates. Their phenomenological analysis in the context of two-Higgs-doublet models yields strong constraints, in some cases weakened by a cancellation mechanism among contributions from neutral scalars. While the corresponding parameter combinations do not yet have to be unnaturally small, the constraints are likely to preclude large effects in other CP-violating observables. Nevertheless, the generically expected contributions to electric dipole moments in this class of models lie within the projected sensitivity of the next-generation experiments.
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