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Garcia-Recio, C., Geng, L. S., Nieves, J., Salcedo, L. L., Wang, E., & Xie, J. J. (2013). Low-lying even parity meson resonances and spin-flavor symmetry revisited. Phys. Rev. D, 87(9), 096006–18pp.
Abstract: We review and extend the model derived in Garcia-Recio et al. [Phys. Rev. D 83, 016007 (2011)] to address the dynamics of the low-lying even-parity meson resonances. This model is based on a coupled-channels spin-flavor extension of the chiralWeinberg-Tomozawa Lagrangian. This interaction is then used to study the S-wave meson-meson scattering involving members not only of the pi octet, but also of the rho nonet. In this work, we study in detail the structure of the SU(6)-symmetry-breaking contact terms that respect (or softly break) chiral symmetry. We derive the most general local (without involving derivatives) terms consistent with the chiral-symmetry-breaking pattern of QCD. After introducing sensible simplifications to reduce the large number of possible operators, we carry out a phenomenological discussion of the effects of these terms. We show how the inclusion of these pieces leads to an improvement of the description of the J(P) = 2(+) sector, without spoiling the main features of the predictions obtained in the original model in the JP = 0(+) and J(P) = 1(+) sectors. In particular, we find a significantly better description of the I-G(J(PC)) =0(+)(2(++)), 1(-)(2(++)) and the I(JP)=1/2(2(+)) sectors, which correspond to the f(2)(1270), a(2)(1320), and K-2(*)(1430) quantum numbers, respectively.
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Botella, F. J., Branco, G. C., & Rebelo, M. N. (2013). Invariants and flavour in the general Two Higgs Doublet Model. Phys. Lett. B, 722(1-3), 76–82.
Abstract: The flavour structure of the general Two Higgs Doublet Model (2HDM) is analysed and a detailed study of the parameter space is presented, showing that flavour mixing in the 2HDM can be parametrized by various unitary matrices which arise from the misalignment in flavour space between pairs of various Hermitian flavour matrices which can be constructed within the model. This is entirely analogous to the generation of the CKM matrix in the Standard Model (SM). We construct weak basis invariants which can give insight into the physical implications of any flavour model, written in an arbitrary weak basis (WB) in the context of 2HDM. We apply this technique to two special cases, models with MFV and models with NNI structures. In both cases non-trivial CP-odd WB invariants arise in a mass power order much smaller than what one encounters in the SM, which can have important implications for baryogenesis in the framework of the general 2HDM.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., Oyanguren, A., & Villanueva-Perez, P. (2013). Study of the decay (B)over-bar(0) -> Lambda(+)(c) (p)over-bar pi(+) pi(-) and its intermediate states. Phys. Rev. D, 87(9), 092004–17pp.
Abstract: We study the decay (B) over bar (0) -> Lambda(+)(c) (p) over bar pi(+) pi(-), reconstructing the Lambda(+)(c) baryon in the pK(-) pi(+) mode, using a data sample of 467 X 10(6) B (B) over bar pairs collected with the BABAR detector at the PEP-II storage rings at SLAC. We measure branching fractions for decays with intermediate Sigma(c) baryons to be B[(B) over bar (0) -> Sigma(c)(2455)(++) (p) over bar (-) pi(-)] = (21.3 +/- 1.0 +/- 1.0 +/- 5.5) X 10(-5), B[(B) over bar (0) -> Sigma(c)(2520)(++) (p) over bar (-) pi(-)] = (11.5 +/- 1.0 +/- 0.5 +/- 3.0) X 10(-5), B[(B) over bar (0) -> Sigma(c)(2455)(0) (p) over bar (-) pi(-)] – (9.1 +/- 0.7 +/- 0.4 +/- 2.4) X 10(-5), and B[(B) over bar (0) -> Sigma(c)(2520)(++) (p) over bar (-) pi(-)] – (2.2 +/- 0.7 +/- 0.1 +/- 0.6) X 10(-5), where the uncertainties are statistical, systematic, and due to the uncertainty on the Lambda(+)(c) -> pK(-) pi(+) branching fraction, respectively. For decays without Sigma(c)(2455) or Sigma(c)(2520) resonances, we measure B[(B) over bar (0) -> Lambda(+)(c) (p) over bar pi(+) pi(-)](non-Sigma c) =(79 +/- 4 +/- 4 +/- 20) X 10(-5). The total branching fraction is determined to be B[(B) over bar (0) -> Lambda(+)(c) (p) over bar pi(+) pi(-)](total) = (123 +/- 5 +/- 7 +/- 32) X 10(-5). We examine multibody mass combinations in the resonant three-particle Sigma(c) final states and in the four-particle Lambda(+)(c) (p) over bar pi(+) pi(-) final state, and observe different characteristics for the (p) over bar pi combination in neutral versus doubly charged Sigma(c) decays.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., Oyanguren, A., & Villanueva-Perez, P. (2013). Study of e(+)e(-) -> p(p)over-bar via initial-state radiation at BABAR. Phys. Rev. D, 87(9), 092005–18pp.
Abstract: The process e(+)e(-) -> p (p) over bar gamma is studied using 469 fb(-1) of integrated luminosity collected with the BABAR detector at the SLAC National Accelerator Laboratory, at an e(+)e(-) center-of-mass energy of 10.6 GeV. From the analysis of the p (p) over bar invariant mass spectrum, the energy dependence of the cross section for e(+)e(-) -> p (p) over bar is measured from threshold to 4.5 GeV. The energy dependence of the ratio of electric and magnetic form factors, vertical bar G(E)/G(M)vertical bar, and the asymmetry in the proton angular distribution are measured for p (p) over bar masses below 3 GeV. We also measure the branching fractions for the decays J/psi -> p (p) over bar and psi(2S) -> p (p) over bar are also determined.
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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). Observation of Associated Near-Side and Away-Side Long-Range Correlations in root S-NN=5.02 TeV Proton-Lead Collisions with the ATLAS Detector. Phys. Rev. Lett., 110(18), 182302–18pp.
Abstract: Two-particle correlations in relative azimuthal angle (Delta phi) and pseudorapidity (Delta eta) are measured in root S-NN = 5.02 TeV p + Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1 μb(-1) of data as a function of transverse momentum (p(T)) and the transverse energy (Sigma E-T(Pb)) summed over 3.1 < eta < 4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2 < vertical bar Delta eta vertical bar < 5) “near-side” (Delta phi similar to 0) correlation that grows rapidly with increasing Sigma E-T(Pb). A long-range “away-side” (Delta phi similar to pi) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small Sigma E-T(Pb), is found to match the near-side correlation in magnitude, shape (in Delta eta and Delta phi) and Sigma E-T(Pb) dependence. The resultant Delta phi correlation is approximately symmetric about pi/2, and is consistent with a dominant cos2 Delta phi modulation for all Sigma E-T(Pb) ranges and particle p(T).
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