LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2015). Search for CP violation in D-0 -> pi(-)pi(+)pi(0) decays with the energy test. Phys. Lett. B, 740, 158–167.
Abstract: A search for time-integrated CP violation in the Cabibbo-suppressed decay D-0 -> pi(-)pi(+)pi(0) ir is performed using for the first time an unbinned model-independent technique known as the energy test. Using proton-proton collision data, corresponding to an integrated luminosity of 2.0 fb(-1) collected by the LHCb detector at a centre-of-mass energy of root s = 8 TeV, the world's best sensitivity to CP violation in this decay is obtained. The data are found to be consistent with the hypothesis of CP symmetry with a p-value of (2.6 +/- 0.5)%.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2015). Determination of gamma and-2 beta(s) from charmless two-body decays of beauty mesons. Phys. Lett. B, 741, 1–11.
Abstract: Using the latest LHCb measurements of time-dependent CP violation in the B-s(0) -> K+K- decay, a U-spin relation between the decay amplitudes of B-s(0) -> K+K- and B-0 -> p(+)p(-) decay processes allows constraints to be placed on the angle gamma of the unitarity triangle and on the B-s(0) mixing phase -2 beta(s). Results from an extended approach, which uses additional inputs on B-0 -> pi(0)pi(0) and B+ -> pi(+)pi(0) decays from other experiments and exploits isospin symmetry, are also presented. The dependence of the results on the maximum allowed amount of U-spin breaking is studied. At 68% probability, the value gamma =( 63.5(-6.7)(+7.2))degrees modulo 180 degrees is determined. In an alternative analysis, the value -2 beta(s)= – 0.12(-0.16)(+ 0.14) rad is found. In both measurements, the uncertainties due to U-spin breaking effects up to 50% are included.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., Oyanguren, A., & Villanueva-Perez, P. (2015). Study of B-+/-,B-0 -> J/psi(K+K-K +/-,0) and search for B-0 -> J/psi phi at BABAR. Phys. Rev. D, 91(1), 012003–12pp.
Abstract: We study the rare B meson decays B-+/-,B-0 -> J/psi(K+K-K +/-,0), B-+/-,B-0 -> J/psi phi K-+/-,K-0, and search for B-0 -> J/psi phi, using 469 x 10(6) B (B) over bar events collected at the Upsilon(4S) resonance with the BABAR detector at the PEP-II e(+)e(-) asymmetric energy collider. We present new measurements of branching fractions and a study of the J/psi phi mass distribution in search of new charmonium-like states. In addition, we search for the decay B-0 -> J/psi phi and find no evidence of a signal.
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LHCb Collaboration(Aaij, R. et al), Martinez-Vidal, F., Oyanguren, A., Ruiz Valls, P., & Sanchez Mayordomo, C. (2015). Measurement of the Z plus b-jet cross-section in pp collisions at root s=7 TeV in the forward region. J. High Energy Phys., 01(1), 064–15pp.
Abstract: The associated production of a Z boson or an off-shell photon gamma* with a bottom quark in the forward region is studied using proton-proton collisions at a centre-of-mass energy of 7TeV. The Z bosons are reconstructed in the Z/gamma* -> mu(+)mu(-) final state from muons with a transverse momentum larger than 20 GeV, while two transverse momentum thresholds are considered for jets (10 GeV and 20 GeV). Both muons and jets are reconstructed in the pseudorapidity range 2.0 < eta < 4.5. The results are based on data corresponding to 1.0 fb(-1) recorded in 2011 with the LHCb detector. The measurement of the Z+b-jet cross-section is normalized to the Z+jet cross-section. The measured cross-sections are (Z/ (mu+ mu-) + b-jet) = 295 60 (stat) 51 (syst) 10 (lumi) fb (0.1) for p T(jet) > 10 GeV, and (Z/ (mu+ mu-) + b-jet) = 128 36 (stat) 22 (syst) 5 (lumi) fb (0.2) for p T(jet) > 20 GeV.
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BABAR Collaboration(Lees, J. P. et al), Martinez-Vidal, F., Oyanguren, A., & Villanueva-Perez, P. (2014). Bottomonium spectroscopy and radiative transitions involving the chi(bJ)(1P, 2P) states at BABAR. Phys. Rev. D, 90(11), 112010–20pp.
Abstract: We use (121 +/- 1) million Upsilon(3S) and (98 +/- 1) million Upsilon(2S) mesons recorded by the BABAR detector at the PEP-II e(+)e(-) collider at SLAC to perform a study of radiative transitions involving the chi(bJ)(1P, 2P) states in exclusive decays with mu(+)mu(-)gamma gamma final states. We reconstruct twelve channels in four cascades using two complementary methods. In the first we identify both signal photon candidates in the electromagnetic calorimeter (EMC), employ a calorimeter timing-based technique to reduce backgrounds, and determine branching-ratio products and fine mass splittings. These results include the best observational significance yet for the chi(b0)(2P) -> gamma Upsilon(2S) and chi(b0)(1P) -> gamma Upsilon(1S) transitions. In the second method, we identify one photon candidate in the EMC and one which has converted into an e(+)e(-) pair due to interaction with detector material, and we measure absolute product branching fractions. This method is particularly useful for measuring Upsilon(3S) -> gamma chi(b1,2)(1P) decays. Additionally, we provide the most up-to-date derived branching fractions, matrix elements and mass splittings for chi(b) transitions in the bottomonium system. Using a new technique, we also measure the two lowest-order spin-dependent coefficients in the nonrelativistic QCD Hamiltonian.
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