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Nys, J., Mathieu, V., Fernandez-Ramirez, C., Hiller Blin, A. N., Jackura, A., Mikhasenko, M., et al. (2017). Finite-energy sum rules in eta photoproduction off a nucleon. Phys. Rev. D, 95(3), 034014–20pp.
Abstract: The reaction gamma N -> eta N is studied in the high-energy regime (with photon lab energies E gamma(lab) > 4 GeV) using information from the resonance region through the use of finite-energy sum rules. We illustrate how analyticity allows one to map the t dependence of the unknown Regge residue functions. We provide predictions for the energy dependence of the beam asymmetry at high energies.
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Gomez Dumm, D., Noguera, S., & Scoccola, N. N. (2017). eta-gamma and eta(')-gamma transition form factors in a nonlocal NJL model. Phys. Rev. D, 95(5), 054006–19pp.
Abstract: We study the eta and eta(') distribution amplitudes (DAs) in the context of a nonlocal SU(3)(L) circle times SUd(3)(R) chiral quark model. The corresponding Lagrangian allows us to reproduce the phenomenological values of pseudoscalar meson masses and decay constants, as well as the momentum dependence of the quark propagator arising from lattice calculations. It is found that the obtained DAs have two symmetric maxima, which arise from new contributions generated by the nonlocal character of the interactions. These DAs are then applied to the calculation of the eta-gamma and eta(')-gamma transition form factors. Implications of our results regarding higher twist corrections and/or contributions to the transition form factors originated by gluon-gluon components in the eta and eta(') mesons are discussed.
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de Rham, C., & Motohashi, H. (2017). Caustics for spherical waves. Phys. Rev. D, 95(6), 064008–13pp.
Abstract: We study the development of caustics in shift-symmetric scalar field theories by focusing on simple waves with an SO(p)-symmetry in an arbitrary number of space dimensions. We show that the pure Galileon, the DBI-Galileon, and the extreme-relativistic Galileon naturally emerge as the unique set of caustic-free theories, highlighting a link between the caustic-free condition for simple SO(p)-waves and the existence of either a global Galilean symmetry or a global (extreme-) relativistic Galilean symmetry.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., & Oyanguren, A. (2017). Cross sections for the reactions e(+)e(-) -> (KSKL0)-K-0 pi(0), (KSKL0)-K-0 eta, and (KSKL0)-K-0 pi(0)pi(0) from events with initial-state radiation. Phys. Rev. D, 95(5), 052001–16pp.
Abstract: We study the processes e(+)e(-) -> (KSKL0)-K-0 pi(0)gamma, (KSKL0)-K-0 eta gamma, and (KSKL0)-K-0 pi(0)pi(0)gamma, where the photon is radiated from the initial state, providing cross section measurements for the hadronic final states over a continuum of center-of-mass energies. The results are based on 469 fb(-1) of data collected at or near the psi(4S) resonance with the BABAR detector at SLAC. We present the first measurements of the e(+)e(-) -> (KSKL0)-K-0 pi(0), (KSKL0)-K-0 eta, and (KSKL0)-K-0 pi(0)pi(0) cross sections up to a center-of-mass energy of 4 GeV and study their intermediate resonance structures. We observe J/psi decays to all of these final states for the first time, present measurements of their J/psi branching fractions, and search for psi(2S)decays.
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Ortega, P. G., Segovia, J., Entem, D. R., & Fernandez, F. (2016). Canonical description of the new LHCb resonances. Phys. Rev. D, 94(11), 114018–7pp.
Abstract: The LHCb Collaboration has recently observed four J/psi phi structures called X(4140), X(4274), X(4500), and X(4700) in the B+ -> J/psi phi K+ decays. We study them herein using a nonrelativistic constituent quark model in which the degrees of freedom are quark-antiquark and meson-meson components. The X(4140) resonance appears as a cusp in the J/psi phi channel due to the near coincidence of the D-s(+/-) D-s(*+/-) and J/psi phi mass thresholds. The remaining three [X(4274), X(4500), and X(4700)] appear as conventional charmonium states with quantum numbers 3(3)P(1), 4(3)P(0), and 5(3)P(0), respectively, and their masses and widths are slightly modified due to their coupling with the corresponding closest meson-meson thresholds. A particular feature of our quark model is a lattice-based screened linear confining interaction that has been constrained in the light-quark sector and usually produces higher excited heavy-quark states with lower masses than standard quark model predictions.
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