A. B. Breon

Measurements of moments of the hadronic mass distribution in semileptonic B decays

B. Aubert, R. Barate, D. Boutigny, F. Couderc, J.-M. Gaillard, A. Hicheur, Y. Karyotakis, J. P. Lees, V. Tisserand, A. Zghiche, A. Palano, A. Pompili, J. C. Chen, N. D. Qi, G. Rong, P. Wang, Y. S. Zhu, G. Eigen, I. Ofte, B. Stugu, G. S. Abrams, A. W. Borgland, A. B. Breon, D. N. Brown, J. Button-Shafer, R. N. Cahn, E. Charles, C. T. Day, M. S. Gill, A. V. Gritsan, Y. Groysman, R. G. Jacobsen, R. W. Kadel, J. Kadyk, L. T. Kerth, Yu. G. Kolomensky, G. Kukartsev, C. LeClerc, M. E. Levi, G. Lynch, L. M. Mir, P. J. Oddone, T. J. Orimoto, M. Pripstein, N. A. Roe, M. T. Ronan, V. G. Shelkov, A. V. Telnov, W. A. Wenzel, K. Ford, T. J. Harrison, C. M. Hawkes, S. E. Morgan, A. T. Watson, N. K. Watson, M. Fritsch, K. Goetzen, T. Held, H. Koch, B. Lewandowski, M. Pelizaeus, K. Peters, H. Schmuecker, M. Steinke, J. T. Boyd, N. Chevalier, W. N. Cottingham, M. P. Kelly, T. E. Latham, C. Mackay, F. F. Wilson, K. Abe, T. Cuhadar-Donszelmann, C. Hearty, T. S. Mattison, J. A. McKenna, D. Thiessen, P. Kyberd, A. K. McKemey, L. Teodorescu, V. E. Blinov, A. D. Bukin, V. B. Golubev, V. N. Ivanchenko, E. A. Kravchenko, A. P. Onuchin, S. I. Serednyakov, Yu. I. Skovpen, E. P. Solodov, A. N. Yushkov, D. Best, M. Bruinsma, M. Chao, I. Eschrich, D. Kirkby, A. J. Lankford, M. Mandelkern, R. K. Mommsen, W. Roethel, D. P. Stoker, C. Buchanan, B. L. Hartfiel, J. W. Gary, J. Layter, B. C. Shen, K. Wang, D. del Re, H. K. Hadavand, E. J. Hill, D. B. MacFarlane, H. P. Paar, Sh. Rahatlou, V. Sharma, J. W. Berryhill, C. Campagnari, B. Dahmes, S. L. Levy, O. Long, A. Lu, M. A. Mazur, J. D. Richman, W. Verkerke, T. W. Beck, J. Beringer, A. M. Eisner, C. A. Heusch, W. S. Lockman, T. Schalk, R. E. Schmitz, B. A. Schumm, A. Seiden, P. Spradlin, W. Walkowiak, D. C. Williams, M. G. Wilson, J. Albert, E. Chen, G. P. Dubois-Felsmann, A. Dvoretskii, R. J. Erwin, D. G. Hitlin, I. Narsky, T. Piatenko, F. C. Porter, A. Ryd, A. Samuel, S. Yang, S. Jayatilleke, G. Mancinelli, B. T. Meadows, M. D. Sokoloff, T. Abe, F. Blanc, P. Bloom, S. Chen, P. J. Clark, W. T. Ford, U. Nauenberg, A. Olivas, P. Rankin, J. Roy, J. G. Smith, W. C. van Hoek, L. Zhang, J. L. Harton, T. Hu, A. Soffer, W. H. Toki, R. J. Wilson, J. Zhang, D. Altenburg, T. Brandt, J. Brose, T. Colberg, M. Dickopp, E. Feltresi, A. Hauke, H. M. Lacker, E. Maly, R. Müller-Pfefferkorn, R. Nogowski, S. Otto, J. Schubert, K. R. Schubert, R. Schwierz, B. Spaan, D. Bernard, G. R. Bonneaud, F. Brochard, P. Grenier, Ch. Thiebaux, G. Vasileiadis, M. Verderi, D. J. Bard, A. Khan, D. Lavin, F. Muheim, S. Playfer, M. Andreotti, V. Azzolini, D. Bettoni, C. Bozzi, R. Calabrese, G. Cibinetto, E. Luppi, M. Negrini, L. Piemontese, A. Sarti, E. Treadwell, R. Baldini-Ferroli, A. Calcaterra, R. de Sangro, G. Finocchiaro, P. Patteri, M. Piccolo, A. Zallo, A. Buzzo, R. Capra, R. Contri, G. Crosetti, M. Lo Vetere, M. Macri, M. R. Monge, S. Passaggio, C. Patrignani, E. Robutti, A. Santroni, S. Tosi, S. Bailey, M. Morii, E. Won, R. S. Dubitzky, U. Langenegger, W. Bhimji, D. A. Bowerman, P. D. Dauncey, U. Egede, J. R. Gaillard, G. W. Morton, J. A. Nash, G. P. Taylor, G. J. Grenier, S.-J. Lee, U. Mallik, J. Cochran, H. B. Crawley, J. Lamsa, W. T. Meyer, S. Prell, E. I. Rosenberg, J. Yi, M. Davier, G. Grosdidier, A. Höcker, S. Laplace, F. Le Diberder, V. Lepeltier, A. M. Lutz, T. C. Petersen, S. Plaszczynski, M. H. Schune, L. Tantot, G. Wormser, V. Brigljević, C. H. Cheng, D. J. Lange, M. C. Simani, D. M. Wright, A. J. Bevan, J. P. Coleman, J. R. Fry, E. Gabathuler, R. Gamet, M. Kay, R. J. Parry, D. J. Payne, R. J. Sloane, C. Touramanis, J. J. Back, P. F. Harrison, G. B. Mohanty, C. L. Brown, G. Cowan, R. L. Flack, H. U. Flaecher, S. George, M. G. Green, A. Kurup, C. E. Marker, T. R. McMahon, S. Ricciardi, F. Salvatore, G. Vaitsas, M. A. Winter, D. Brown, C. L. Davis, J. Allison, N. R. Barlow, R. J. Barlow, P. A. Hart, M. C. Hodgkinson, G. D. Lafferty, A. J. Lyon, J. C. Williams, A. Farbin, W. D. Hulsbergen, A. Jawahery, D. Kovalskyi, C. K. Lae, V. Lillard, D. A. Roberts, G. Blaylock, C. Dallapiccola, K. T. Flood, S. S. Hertzbach, R. Kofler, V. B. Koptchev, T. B. Moore, S. Saremi, H. Staengle, S. Willocq, R. Cowan, G. Sciolla, F. Taylor, R. K. Yamamoto, D. J. J. Mangeol,

Performance, radiation damage, and future plans of the BABAR silicon vertex tracker

The BABAR silicon vertex tracker (SVT) has been in operation for four years at the PEP-II electron-positron storage ring. During this time the SVT modules have accumulated a radiation dose up to 2 Mrad. We study the degradation in the performance of the SVT due to this accumulated dose which is highly non uniform across the device and also within the individual silicon detectors. To extrapolate the performance of the device to the future we study separately the effect of the irradiation on silicon detectors, front end integrated circuits and on a complete detector module under controlled radiation conditions, using a /sup 60/Co source and a 0.9 GeV e/sup -/ beam. We compare the results to the data from the SVT. In particular we show the dependence of the charge collection efficiency on the radiation dose even when a small stripe of the module is irradiated up to space charge sign inversion. Since the modules that are located in the plane of the beams will suffer significant radiation damage, we will describe our plans for their replacement in 2005 and for the operation of the SVT through the lifetime of the BABAR experiment.

Status and future plans of the BABAR silicon vertex tracker

Abstract A brief summary of the design goals, description, and performance of the BABAR Silicon Vertex Tracker is given. Results from radiation hardness tests are discussed, which indicate satisfactory operation up to 5 Mrad of accumulated radiation. The local alignment procedure has made significant improvements recently, and four readout sections were recovered during the BABAR shutdown in 2002.

Measurement of the branching fraction of Υ(4S)→B0B̄0

We report the first measurement of the branching fraction f00 for Υ(4S)→B0B 0. The data sample consists of 81.7  fb-1 collected at the Υ(4S) resonance with the BABAR detector at the SLAC PEP-II asymmetric-energy e+e- storage ring. Using partial reconstruction of the decay B 0→D*+l-ν l in which only the charged lepton and the soft pion from the decay D*+→D0π+ are reconstructed, we obtain f00=0.487±0.010(stat)±0.008(syst). Our result does not depend on the branching fractions of B 0→D*+l-ν l and D*+→D0π+ decays, on the ratio of the charged and neutral B meson lifetimes, nor on the assumption of isospin symmetry.

Measurements of CP-Violating Asymmetries in B0→ K s 0π0 Decays

We present a measurement of the time-dependent CP-violating (CPV) asymmetries in B0-->K(0)(S)pi(0) decays based on 124x10(6) Upsilon(4S)-->BB decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. In a sample containing 122+/-16 signal decays, we obtain the magnitudes of the direct CPV asymmetry CK(0)(S)(pi(0))=0.40(+0.27)(-0.28)+/-0.09 and of the CPV asymmetry in the interference between mixing and decay SK(0)(S)(pi(0))=0.48(+0.38)(-0.47)+/-0.06 where the first error is statistical and the second systematic.

Measurement of the B+/B0 production ratio from the Υ(4S) meson using B+→J/ψK+ and B0→J/ψKS0 decays

We report a measurement of the production ratio of charged and neutral B mesons from Υ(4S) decays based on the ratio of efficiency-corrected yields for the charmonium modes J/ψK+ and J/ψKs0 with 81.9 fb-1 of data collected with the BABAR detector on the Υ(4S) resonance at 10.580 GeV. We find a value of 1.006±0.036(stat)±0.031(syst) for the ratio R+/0=Γ(Υ(4S)→B+B-)/Γ(Υ(4S)→B0B0).

Search for factorization-suppressed B→χcK(*) decays

We search for the factorization-suppressed decays B→χc0K(*) and B→χc2K(*), with χc0 and χc2 decaying into J/ψγ, using a sample of 124×106 BB events collected with the BABAR detector at the PEP-II storage ring of the Stanford Linear Accelerator Center. We find no significant signal and set upper bounds for the branching fractions.

Improved measurement of the Cabibbo-Kobayashi-Maskawa angle α using B0(B̄)→ρ+ρ- decays

We present results from an analysis of B(0)B(0)--> rho(+)rho(-) using 232 x 10(6) Gamma (4S) --> BB decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. We measure the longitudinal polarization fraction f(L) = 0.978 +/- 0.014(stat) + 0.021 / -0.029(syst) and the CP-violating parameters S(L)= -0.33 +/- 0.24(stat) + 0.08 / -0.14(syst) and C(L)= -0.03 +/- 0.18(stat) +/- 0.09(syst). Using an isospin analysis of B --> rhorho decays, we determine the unitarity triangle parameter alpha. The solution compatible with the standard model is alpha = (100 +/- 13) degrees.

Search for decays of B0→e+e-, B0→μ+μ-, B0→e± μ

We present a search for the decays B0->e+e-, B0->mu+mu-, and B0->e+- mu-+ in data collected at the Y(4S) resonance with the Babar detector at the SLAC B Factory. Using a data set of 111 fb^-1, we find no evidence for a signal in any of the three channels investigated and set the following branching fraction upper limits at the 90% confidence level: B(B0->e+e-) mu+mu-) e+-mu-+) < 18 x 10^-8.

Study of B→π ν and B→ρ ν decays and determination of

We present an analysis of exclusive charmless semileptonic B-meson decays based on 83×106 BB pairs recorded with the BABAR detector at the Υ(4S) resonance. Using isospin symmetry, we measure branching fractions B(B0→π- +ν)=(1.38±0.10±0.16±0.08)×10-4 and B(B0→ρ- +ν)=(2.14±0.21±0.48±0.28)×10-4, where the errors are statistical, experimental systematic, and due to form-factor shape uncertainties. We compare the measured distribution in q2, the momentum-transfer squared, with theoretical predictions for the form factors from lattice QCD and light-cone sum rules, and extract the Cabibbo-Kobayashi- Maskawa (CKM) matrix element |Vub|=(3.82±0.14±0.22±0.11-0. 52+0.88)×10-3 from B→π ν, where the fourth error reflects the uncertainty of the form-factor normalization.