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BABAR Collaboration(del Amo Sanchez, P. et al), Lopez-March, N., Martinez-Vidal, F., & Oyanguren, A. (2011). Searches for the baryon- and lepton-number violating decays B0 -> Lambda_c+ l-, B- --> Lambda l-, and B- --> (Lambda)bar l-. Phys. Rev. D, 83(9), 091101–8pp.
Abstract: Searches for B mesons decaying to final states containing a baryon and a lepton are performed, where the baryon is either Lambda(c) or Lambda and the lepton is a muon or an electron. These decays violate both baryon and lepton number and would be a signature of physics beyond the standard model. No significant signal is observed in any of the decay modes, and upper limits in the range (3.2-520) x 10(-8) are set on the branching fractions at the 90% confidence level.
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BABAR Collaboration(del Amo Sanchez, P. et al), Lopez-March, N., Martinez-Vidal, F., & Oyanguren, A. (2011). Search for CP violation in the decay D(+/-) --> K_S pi(+/-). Phys. Rev. D, 83(7), 071103–8pp.
Abstract: We report on a search for CP violation in the decay D-+/- -> K-S(0)pi(+/-) using a data set corresponding to an integrated luminosity of 469 fb(-1) collected with the BABAR detector at the PEP-II asymmetric energy e(+)e(-) storage rings. The CP- violating decay rate asymmetry A(CP) is determined to be (-0.44 +/- 0: 13(stat) +/- 0.10(syst))%, consistent with zero at 2.7 sigma and with the standard model prediction of (-0.332 +/- 0.006)%. This is currently the most precise measurement of this parameter.
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BABAR Collaboration(del Amo Sanchez, P. et al), Lopez-March, N., Martinez-Vidal, F., & Oyanguren, A. (2011). Measurement of the gamma gamma* -> eta and gamma gamma* -> eta ' transition form factors. Phys. Rev. D, 84(5), 052001–19pp.
Abstract: We study the reactions e(+)e(-) --> e(+)e(-) eta((')) in the single-tag mode and measure the gamma gamma* --> eta((')) transition form factors in the momentum-transfer range from 4 to 40 GeV(2). The analysis is based on 469 fb(-1) of integrated luminosity collected at PEP-II with the BABAR detector at e(+)e(-) center-of-mass energies near 10.6 GeV.
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BABAR Collaboration(del Amo Sanchez, P. et al), Lopez-March, N., Martinez-Vidal, F., & Oyanguren, A. (2011). Search for Production of Invisible Final States in Single-Photon Decays of Gamma(1S). Phys. Rev. Lett., 107(2), 021804–7pp.
Abstract: We search for single-photon decays of the Gamma(1S) resonance, Gamma -> gamma + invisible, where the invisible state is either a particle of definite mass, such as a light Higgs boson A(0), or a pair of dark matter particles, chi(chi) over bar. Both A(0) and chi are assumed to have zero spin. We tag Gamma(1S) decays with a dipion transition Gamma(1S) -> pi(+)pi(-)Y(1S) and look for events with a single energetic photon and significant missing energy. We find no evidence for such processes in the mass range m(A0) <= 9.2 GeV and m(chi) <= 4.5 GeV in the sample of 98 x 10(6) Gamma(2S) decays collected with the BABAR detector and set stringent limits on new physics models that contain light dark matter states.
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BABAR Collaboration(Lees, J. P. et al), Lopez-March, N., Martinez-Vidal, F., & Oyanguren, A. (2011). Measurement of the mass and width of the D_s1 (2536)+ meson. Phys. Rev. D, 83(7), 072003–14pp.
Abstract: The decay width and mass of the D-s1(2536)(+) meson are measured via the decay channel D-s1(+) -> (D*+KS0) using 385 fb(-1) of data recorded with the BABAR detector in the vicinity of the Gamma(4S) resonance at the PEP-II asymmetric-energy electron-positron collider. The result for the decay width is Gamma(D-s1(+)) = 92 +/- 0.03(stat.) +/- 0.04(syst.) MeV. For the mass, a value of m(D-s1(+)) = 2535.08 +/- 0.01(stat.) +/- 0.15(syst.) MeV/c(2) is obtained. The mass difference between the D-s1(+) and the D*+ is measured to be m(D-s1(+)) – m(D*+) = 524.83 +/- 0.01(stat.) +/- 0.04(syst.) MeV/c(2), representing a significant improvement compared to the current world average. The unnatural spin-parity assignment for the D-s1(+) meson is confirmed.
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