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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., Oyanguren, A., & Villanueva-Perez, P. (2013). Search for direct CP violation in singly Cabibbo-suppressed D-+/- -> K+K-pi(+/-) decays. Phys. Rev. D, 87(5), 052010–12pp.
Abstract: We report on a search for direct CP violation in the singly Cabibbo-suppressed decay D+ -> K+K-pi(+/-) using a data sample of 476 fb(-1) of e(+)e(-) annihilation data accumulated with the BABAR detector at the SLAC PEP-II electron-positron collider, running at and just below the energy of the Upsilon(4S) resonance. The integrated CP-violating decay rate asymmetry A(CP) is determined to be (0.37 +/- 0.30 +/- 0.15)%. Model-independent and model-dependent Dalitz plot analysis techniques are used to search for CP-violating asymmetries in the various intermediate states. We find no evidence for CP-violation asymmetry.
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Campanario, F., Kerner, M., Ninh, L. D., & Zeppenfeld, D. (2013). WZ production in association with two jets at next-to-leading order in QCD. Phys. Rev. Lett., 111(5), 052003–4pp.
Abstract: We report on the calculation of W-+/- Zjj production with leptonic decays at hadron-hadron colliders at next-to-leading order in QCD. These processes are important both to test the quartic gauge couplings of the standard model and because they constitute relevant backgrounds to beyond standard model physics searches. Our results show that the next-to-leading order corrections reduce significantly the scale uncertainties and have a nontrivial phase space dependence.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., Oyanguren, A., & Villanueva-Perez, P. (2013). Observation of direct CP violation in the measurement of the Cabibbo-Kobayashi-Maskawa angle gamma with B-+/- -> Dd(()*()) K-(*()+/-) decays. Phys. Rev. D, 87(5), 052015–12pp.
Abstract: We report the determination of the Cabibbo-Kobayashi-Maskawa CP-violating angle gamma through the combination of various measurements involving B-+/- -> DK +/-, B-+/- -> D*K-+/-, and B-+/- -> DK*(+/-) decays performed by the BABAR experiment at the PEP-II e(+)e(-) collider at SLAC National Accelerator Laboratory. Using up to 474 million B (B) over bar pairs, we obtain gamma = (69(-16)(+17))degrees modulo 180 degrees. The total uncertainty is dominated by the statistical component, with the experimental and amplitude-model systematic uncertainties amounting to +/- 4 degrees. The corresponding two-standard-deviation region is 41 degrees < gamma < 102 degrees. This result is inconsistent with gamma = 0 with a significance of 5.9 standard deviations.
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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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Vijande, J., Valcarce, A., & Richard, J. M. (2013). Adiabaticity and color mixing in tetraquark spectroscopy. Phys. Rev. D, 87(3), 034040–5pp.
Abstract: We revisit the role of color mixing in the quark model calculation of tetraquark states, and compare simple pairwise potentials to more elaborate string models with three-and four-body forces. We attempt to disentangle the improved dynamics of confinement from the approximations made in the treatment of the internal color degrees of freedom.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., Oyanguren, A., & Villanueva-Perez, P. (2013). Search for a low-mass scalar Higgs boson decaying to a tau pair in single-photon decays of Y(1S). Phys. Rev. D, 88(7), 071102–8pp.
Abstract: We search for a low-mass scalar CP-odd Higgs boson, A(0), produced in the radiative decay of the upsilon resonance and decaying into a tau(+)tau(-) pair: Y(1S) -> gamma A(0). The production of Y(1S) mesons is tagged by Y(2S) -> pi(+)pi(-) Y(1S) transitions, using a sample of (98.3 +/- 0.9) x 10(6) Y(2S) mesons collected by the BABAR detector. We find no evidence for a Higgs boson in the mass range 3: 5 <= m(A)0 <= 9: 2 GeV, and combine these results with our previous search for the tau decays of the light Higgs in radiative Y(3S) decays, setting limits on the coupling of A(0) to the b (b) over bar quarks in the range 0.09-1.9. Our measurements improve the constraints on the parameters of the next-to-minimal-supersymmetric Standard Model and similar theories with low-mass scalar degrees of freedom.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., Oyanguren, A., & Villanueva-Perez, P. (2013). Search for di-muon decays of a low-mass Higgs boson in radiative decays of the Gamma(1S). Phys. Rev. D, 87(3), 031102–8pp.
Abstract: We search for di-muon decays of a low-mass Higgs boson (A(0)) produced in radiative Gamma(1S) decays. The Gamma(1S) sample is selected by tagging the pion pair in the Gamma(2S, 3S) -> pi(+)pi(-) Gamma(1S) transitions, using a data sample of 92.8 x 10(6) Gamma(2S) and 116.8 x 10(6) Gamma(3S) events collected by the BABAR detector. We find no evidence for A(0) production and set 90% confidence level upper limits on the product branching fraction B(Gamma(1S) -> gamma Lambda(0)) x B(Lambda(0)->mu(+)mu(-)) in the range of (0.28 – 9.7) x 10(-6) for 0.212 <= m(A0) <= 9.20 GeV/c(2). The results are combined with our previous measurements of Gamma(2S,3S) -> gamma Lambda(0), Lambda(0) -> mu(+)mu(-) to set limits on the effective coupling of the b quark to the Lambda(0).
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., Oyanguren, A., & Villanueva-Perez, P. (2013). Search for a light Higgs boson decaying to two gluons or s(s)over-bar in the radiative decays of Upsilon(1S). Phys. Rev. D, 88(3), 031701–7pp.
Abstract: We search for the decay Upsilon(1S) -> A(0), A(0) -> gg or s (s) over bar, where A(0) is the pseudoscalar light Higgs boson predicted by the next-to-minimal supersymmetric Standard Model. We use a sample of (17.6 +/- 0.3) x 10(6) Upsilon(1S) mesons produced in the BABAR experiment via e(+)e(-) -> Upsilon(2S) -> pi(+)pi(-)Upsilon(1S). We see no significant signal and set 90%-confidence-level upper limits on the product branching fraction B(Upsilon(1S) -> gamma A(0)) . B(A(0) -> gg or s (s) over bar ranging from 10(-6) to 10(-2) for A(0) masses in the range 0.5-9.0 GeV/c(2).
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., Oyanguren, A., & Villanueva-Perez, P. (2013). Search for B -> K-(*()) v(v)over-bar and invisible quarkonium decays. Phys. Rev. D, 87(11), 112005–13pp.
Abstract: We search for the flavor-changing neutral-current decays B -> K-(*()) v (v) over bar, and the invisible decays J/psi -> v (v) over bar and psi(2S) -> v (v) over bar via B -> K-(*())J/psi and B -> K-(*()) psi(2S), respectively, using a data sample of 471 x 10(6) B (B) over bar pairs collected by the BABAR experiment. We fully reconstruct the hadronBic decay of one of the B mesons in the Y(4S) -> B (B) over bar decay, and search for the B -> K-(*()) v (v) over bar decay in the rest of the event. We observe no significant excess of signal decays over background and report branching fraction upper limits of B(B+ -> K+ v (v) over bar) < 3.7 x 10(-5), B(B-0 -> K-0 v<(v)over bar>) < 8.1 x 10(-5), B(B+ -> K*(+) v<(v)over bar>) < 11.6 x 10(-5), B(B-0 -> K*(0) v<(v)over bar>), < 9.3 x 10(-5), and combined upper limits of B(B -> K v<(v)over bar>) < 3.2 x 10(-5) and B(B -> K* v<(v)over bar>) < 7.9 x 10(-5), all at the 90% confidence level. For the invisible quarkonium decays, we report branching fraction upper limits of B(J/psi -> v<(v)over bar>) < 3.9 x 10(-3) and B(psi(2S) -> v<(v)over bar> < 15.5 x 10(-3) at the 90% confidence level. Using the improved kinematic resolution achieved from hadronic reconstruction, we also provide partial branching fraction limits for the B -> K-(*()) v<(v)over bar> decays over the full kinematic spectrum.
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Babichev, E., & Fabbri, A. (2013). Instability of black holes in massive gravity. Class. Quantum Gravity, 30(15), 152001–7pp.
Abstract: We show that linear perturbations around the simplest black hole solution of massive bi-gravity theories, the bi-Schwarzschild solution, exhibit an unstable mode featuring the Gregory-Laflamme instability of higher dimensional black strings. The result is obtained for the massive gravity theory which is free from the Boulware-Deser ghost, as well as for its extension with two dynamical metrics. These results may indicate that static black holes in massive gravity do not exist. For the graviton mass of the order of the Hubble scale, however, the instability timescale is of order of the Hubble time.
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