D. N. Brown

TEST OF A LARGE SCALE PROTOTYPE OF THE DIRC, A CHERENKOV IMAGING DETECTOR BASED ON TOTAL INTERNAL REFLECTION FOR BABAR AT PEP-II

Abstract The principles of the DiRC ring imaging Cherenkov technique are briefly explained and its choice for the B a B ar detector particle identification system is motivated. A large scale prototype of the DIRC for the B a B ar experiment is then described. Details of the design of this prototype and its test in a hadronic particle beam at the CERN-PS are presented, and results from various prototype and test configurations are given. For example, after correcting for geometrical acceptance and estimated collection effects, the number of photoelectrons was measured to be 146 ± 1.8 ± 9 cm −1 , for a track angle of 20° at zero photon transmission distance. The effective attenuation loss was measured to be 4.1 ± 0.7% per meter of bar length, and the observed single photon resolution was 10.0 ± 0.2 mrad. This performance is consistent with what was expected from earlier tests and Monte Carlo simulations, and will be fully adequate for the physics demands of the B a B ar experiment.

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,

Local Alignment of the BABAR Silicon Vertex Tracking Detector

Abstract The B a B ar Silicon Vertex Tracker (SVT) is a five-layer double-sided silicon detector designed to provide precise measurements of the position and direction of primary tracks, and to fully reconstruct low-momentum tracks produced in e + e - collisions at the PEP-II asymmetric collider at Stanford Linear Accelerator Center. This paper describes the design, implementation, performance, and validation of the local alignment procedure used to determine the relative positions and orientations of the 340 SVT wafers. This procedure uses a tuned mix of in situ experimental data and complementary lab-bench measurements to control systematic distortions. Wafer positions and orientations are determined by minimizing a χ 2 computed using these data for each wafer individually, iterating to account for between-wafer correlations. A correction for aplanar distortions of the silicon wafers is measured and applied. The net effect of residual misalignments on relevant physical variables is evaluated in special control samples. The B a B ar data-sample collected between November 1999 and April 2008 is used in the study of the SVT stability.

Track finding efficiency in BABAR

Abstract We describe several studies to measure the charged track reconstruction efficiency and asymmetry of the B A B AR detector. The first two studies measure the tracking efficiency of a charged particle using τ and initial state radiation decays. The third uses the τ decays to study the asymmetry in tracking, the fourth measures the tracking efficiency for low momentum tracks, and the last measures the reconstruction efficiency of K S 0 particles. The first section also examines the stability of the measurements vs. B A B AR running periods.

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.

Extracting longitudinal shower development information from crystal calorimetry plus tracking

arXiv:0711.1593v2 [physics.ins-det] 11 Apr 2008 Extracting longitudinal shower development information from crystal calorimetry plus tracking D.N. Brown a , J. Ilic b , G.B. Mohanty b a Lawrence b Department Berkeley National Laboratory, Berkeley, California 94720, USA of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom Abstract We present an approach to derive longitudinal shower development information from the longitudinally unsegmented B A B AR electromagnetic calorimeter by using tracking information. Our algorithm takes advantage of the good three- dimensional tracking resolution of B A B AR , which provides an independent geometric constraint on the shower as measured in the B A B AR crystal calorimeter. We show that adding the derived longitudinal shower development information to standard particle identification algorithms significantly improves the low-momentum separation of pions from electrons and muons. We also verify that the energy dependence of the electromagnetic shower development we measure is consistent with the prediction of a standard electromagnetic shower model. Key words: Particle Identification, Longitudinal Shower Depth, Electromagnetic Calorimetry, Tracking PACS: 29.40.Gx, 29.40.Vj, 07.05.Kf 1. Introduction In present-day nuclear and particle physics ex- periments, inorganic scintillating crystals, such as NaI(Tl) and CsI(Tl), are often used to construct electromagnetic calorimeters when a precise mea- surement of the energy is required [1]. Crystal calorimeters can be finely segmented in the dimen- sion transverse to the shower development without sacrificing energy resolution, thus providing a good measurement of the lateral shower development. However, engineering and energy resolution consid- erations prevent finely segmenting crystal calorime- ters along the direction of shower development. Both lateral and longitudinal shower development information are useful in charged particle identi- Email addresses: Dave Brown@lbl.gov (D.N. Brown), J.Ilic@warwick.ac.uk (J. Ilic), G.B.Mohanty@warwick.ac.uk (G.B. Mohanty). Preprint submitted to Elsevier Science fication (PID) algorithms, particularly in electron identification. Because crystal calorimeters cannot provide direct longitudinal shower development in- formation, they lose an important input to particle identification. In this paper, we present a technique in which longitudinal shower development information is indirectly extracted from a longitudinally unseg- mented crystal calorimeter in conjunction with a precise tracking system. This technique was devel- oped for use with the B A B AR [2] detector, but it can be applied at any detector which combines crystal calorimetry and precision tracking. It exploits the fact that B A B AR has a tracking system capable of precisely determining the three-dimensional trajec- tory of charged particles, and the fact that these trajectories are not in general collinear with the crystal axes. A similar algorithm has previously been used for sampling calorimeters with fine lateral segmentation [3]. 11 April 2008

Measurement of the e+e- → Ks0 K±π π0 and Ks0 K±π η cross sections using initial-state radiation MEASUREMENT of the ... J. P. LEES et al.

The processes

Tests of CPT symmetry in B0- B 0 mixing and in B0 →c c K0 decays TESTS of CPT SYMMETRY in B0- B 0 ... J. P. LEES et al.

e^+e^-\to K^0_{\scriptscriptstyle S}K^\pm\pi^{\mp}\pi^0

Measurement of [Formula Presented] with hadronic and previously unused muonic [Formula Presented] decays

and

Particle identification using the DIRC in BaBar

e^+e^-\to K^0_{\scriptscriptstyle S}K^\pm\pi^{\mp}\eta