A. K. McKemey

DESIGN AND PERFORMANCE OF THE SLD VERTEX DETECTOR : A 307 MPIXEL TRACKING SYSTEM

This paper describes the design, construction, and initial operation of SLDs upgraded vertex detector which comprises 96 two-dimensional charge-coupled devices (CCDs) with a total of 307 Mpixel. Each pixel functions as an independent particle detecting element, providing space point measurements of charged particle tracks with a typical precision of 4 μm in each co-ordinate. The CCDs are arranged in three concentric cylinders just outside the beam-pipe which surrounds the e+e− collision point of the SLAC Linear Collider (SLC). The detector is a powerful tool for distinguishing displaced vertex tracks, produced by decay in flight of heavy flavour hadrons or tau leptons, from tracks produced at the primary event vertex. The requirements for this detector include a very low mass structure (to minimize multiple scattering) both for mechanical support and to provide signal paths for the CCDs; operation at low temperature with a high degree of mechanical stability; and high speed CCD readout, signal processing, and data sparsification. The lessons learned in achieving these goals should be useful for the construction of large arrays of CCDs or active pixel devices in the future in a number of areas of science and technology.

A CCD-based vertex detector for SLD

Abstract The long R&D programme devoted to this novel form of detector is now coming to an end, and the production of the detector is beginning. This final paper on the R&D work highlights the lessons which have been learned in expanding the coverage from 2 to 500 CCDs.

Quality control and monitoring of radiation damage in charge coupled devices at the Stanford Linear Collider

The radiation testing of CCDs (charge coupled devices) for the vertex detector now installed at the SLAC (Stanford Linear Accelerator Center) Linear Collider is described. In addition to data from the batch qualification, results are also presented on the effect of biasing the CCDs during irradiation. A comparison between Co/sup 60/ and Sr/sup 90/ irradiation is made, and initial results for radiation effects in the vertex detector during operations are presented. It has been shown that commercial CCDs can be used as silicon tracking arrays in the radiation environment close to the interaction point at the SLC (SLAC Linear Collider). Measurements of reset FET turn-on potentials on the vertex detector in situ indicate an accumulated dose consistent with that extrapolated from remote dosimetry. Given the well-defined beam conditions that SLC now routinely maintains, these measurements indicate that the detector operation will not be significantly degraded during its lifetime. >

Future potential of charge coupled devices as detectors of ionising radiation

Abstract The use of charge coupled devices for the detection of ionising radiation is reviewed, results on changes in the charge transfer efficiency due to irradiation are presented, and directions for future work are examined.

Background measurements during PEP-II commissioning

A variety of background detectors were installed at the interaction point of PEP-II for measurements of machine backgrounds during commissioning. Results from these detectors, machine experiments, and simulations have been used to reduce the backgrounds at PEP-II before the installation of the BaBar physics detector.

Measurement of the branching fraction for B±→χc0K±

We present preliminary results for the measurement of the branching fraction of the decay B+- -> chi_c0 K+- from a sample of 75 million BB pairs collected by the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. The chi_c0 meson is reconstructed through its two-body decays to pi+ pi- and K+ K-. We measure BR(B+- -> chi_c0 K+-) * BR(chi_c0 -> pi+ pi-) = (1.08 +- 0.35 (stat) +- 0.10 (syst))*10^-6 and BR(B+- -> chi_c0 K+-) * BR(chi_c0 -> K+ K-) = (1.48 +- 0.44 (stat) +- 0.17 (syst)) * 10^-6. Using the known values for the chi_c0 decays branching fractions, we combined these results to obtain BR(B+- -> chi_c0 K+-) = (2.4 +- 0.7) * 10^-4.

Observation of the decay B0 → ρ+ ρ- and measurement of the branching fraction and polarization

We have observed the rare decay B{sup 0} {yields} {rho}{sup +}{rho}{sup -} in a sample of 89 million B{bar B} pairs recorded with the BABAR detector. We measure the branching fraction {Beta}(B{sup 0} {yields} {rho}{sup +}{rho}{sup -}) = (27{sub -6-7}{sup +7+5}) x 10{sup -6} and determine the longitudinal polarization fraction {Lambda}{sub L}/{Lambda} = 0.99{sub -0.07}{sup +0.01} {+-} 0.03. The results are preliminary.

Measurements of branching fractions in B→φK and B→φπ and search for direct CP violation in B±→φK±

Author(s): Aubert, B; Barate, R; Boutigny, D; Gaillard, JM; Hicheur, A; Karyotakis, Y; Lees, JP; Robbe, P; Tisserand, V; Zghiche, A; Palano, A; Pompili, A; Chen, JC; Qi, ND; Rong, G; Wang, P; Zhu, YS; Eigen, G; Ofte, I; Stugu, B; Abrams, GS; Borgland, AW; Breon, AB; Brown, DN; Button-Shafer, J; Cahn, RN; Charles, E; Day, CT; Gill, MS; Gritsan, AV; Groysman, Y; Jacobsen, RG; Kadel, RW; Kadyk, J; Kerth, LT; Kolomensky, YG; Kral, JF; Kukartsev, G; LeClerc, C; Levi, ME; Lynch, G; Mir, LM; Oddone, PJ; Orimoto, TJ; Pripstein, M; Roe, NA; Romosan, A; Ronan, MT; Shelkov, VG; Telnov, AV; Wenzel, WA; Ford, K; Harrison, TJ; Hawkes, CM; Knowles, DJ; Morgan, SE; Penny, RC; Watson, AT; Watson, NK; Deppermann, T; Goetzen, K; Koch, H; Lewandowski, B; Pelizaeus, M; Peters, K; Schmuecker, H; Steinke, M; Barlow, NR; Boyd, JT; Chevalier, N; Cottingham, WN; Kelly, MP; Latham, TE; Mackay, C; Wilson, FF; Abe, K; Cuhadar-Donszelmann, T; Hearty, C; Mattison, TS; McKenna, JA; Thiessen, D; Kyberd, P; McKemey, AK; Blinov, VE; Bukin, AD | Abstract: We present measurements of branching fractions in the b→sss penguin-dominated decays B+→φK+ and B 0φK0 in a sample of approximately 89 million BB pairs collected by the BABAR detector at the PEP-II asymmetric-energy B-meson factory at SLAC. We determine B(B+→φK+) = (10.0-08+09±0.5)×10-6 and B(B 0→φK0) = (8.4-13+15± 0.5)×10-6. Additionally, we measure the CP-violating charge asymmetry ACP(B±→φK±) = 0.04±0.09±0.01, with a 90% confidence-level interval of [-0.10,0.18], and set an upper limit on the CKM- and color-suppressed decay B+→φπ+, B(B+→φπ +)l0.41× 10-6 (at the 90% confidence level).

Measurement of the branching fraction for B-→D 0K*- - eScholarship

Author(s): Aubert, B; Barate, R; Boutigny, D; Couderc, F; Gaillard, JM; Hicheur, A; Karyotakis, Y; Lees, JP; Robbe, P; Tisserand, V; Zghiche, A; Palano, A; Pompili, A; Chen, JC; Qi, ND; Rong, G; Wang, P; Zhu, YS; Eigen, G; Ofte, I; Stugu, B; Abrams, GS; Borgland, AW; Breon, AB; Brown, DN; Button-Shafer, J; Cahn, RN; Charles, E; Day, CT; Gill, MS; Gritsan, AV; Groysman, Y; Jacobsen, RG; Kadel, RW; Kadyk, J; Kerth, LT; Kolomensky, YG; Kukartsev, G; LeClerc, C; Levi, ME; Lynch, G; Mir, LM; Oddone, PJ; Orimoto, TJ; Pripstein, M; Roe, NA; Romosan, A; Ronan, MT; Shelkov, VG; Telnov, AV; Wenzel, WA; Ford, K; Harrison, TJ; Hawkes, CM; Knowles, DJ; Morgan, SE; Penny, RC; Watson, AT; Watson, NK; Goetzen, K; Held, T; Koch, H; Lewandowski, B; Pelizaeus, M; Peters, K; Schmuecker, H; Steinke, M; Boyd, JT; Chevalier, N; Cottingham, WN; Kelly, MP; Latham, TE; Mackay, C; Wilson, FF; Abe, K; Cuhadar-Donszelmann, T; Hearty, G; Mattison, TS; McKenna, JA; Thiessen, D; Kyberd, P; McKemey, AK; Teodorescu, L; Blinov, VE; Bukin, AD | Abstract: We present a measurement of the branching fraction for the decay B-→K0*-using a sample of approximately 86×106BB pairs collected by the BABAR detector from e+e-collisions near the γ(4S) resonance. The D0is detected through its decays to K-π+, K-π+π0, and K-π+π-π+, and the K*-through its decay to KS0π-. We measure the branching fraction to be B(B-→D0K*-) = [6.3±0.7(stat) ±0.5(syst)]×10-4.

Observation of the Decay [Formula presented], Study of [Formula presented], and Search for [Formula presented]

We present results for the branching fractions and charge asymmetries in