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Type inversion in irradiated silicon: a half truth

ArXiv physics/0409049 (2004)

Authors:

M Swartz, D Bortoletto, V Chiochia, L Cremaldi, S Cucciarelli, A Dorokhov, M Konecki, K Prokofiev, C Regenfus, T Rohe, DA Sanders, S Son, T Speer

Abstract:

Charge collection measurements performed on heavily irradiated p-spray dofz pixel sensors with a grazing angle hadron beam provide a sensitive determination of the electric field within the detectors. The data are compared with a complete charge transport simulation of the sensor which includes signal trapping and charge induction effects. A linearly varying electric field based upon the standard picture of a constant type-inverted effective doping density is inconsistent with the data. A two-trap double junction model implemented in ISE TCAD software can be tuned to produce a doubly-peaked electric field which describes the data reasonably well at two different fluences. The modeled field differs somewhat from previous determinations based upon the transient current technique. The model can also account for the level of signal trapping observed in the data.

Search for Axion-like Particles from the Sun in an Underground Negative-Ion TPC

Nuclear and Particle Physics Proceedings Elsevier 134 (2004) 130-132

Authors:

D Naples, R Ayad, G Bonvincini, M Katz-Hyman, J Martoff, J Miyamoto, V Paolone, V Savinov, I Shipsey

Tests of silicon sensors for the CMS pixel detector

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment Elsevier 530:1-2 (2004) 71-76

Authors:

A Dorokhov, C Amsler, D Bortoletto, V Chiochia, L Cremaldi, S Cucciarelli, M Konecki, K Prokofiev, C Regenfus, T Rohe, D Sanders, S Son, T Speer, M Swartz

First observation of a Υ(1D) state

Physical Review D - Particles, Fields, Gravitation and Cosmology 70:3 (2004)

Authors:

G Bonvicini, D Cinabro, M Dubrovin, A Bornheim, E Lipeles, SP Pappas, A Shapiro, AJ Weinstein, RA Briere, GP Chen, T Ferguson, G Tatishvili, H Vogel, ME Watkins, NE Adam, JP Alexander, K Berkelman, V Boisvert, DG Cassel, JE Duboscq, KM Ecklund, R Ehrlich, RS Galik, L Gibbons, B Gittelman, SW Gray, DL Hartill, BK Heltsley, L Hsu, CD Jones, J Kandaswamy, DL Kreinick, VE Kuznetsov, A Magerkurth, H Mahlke-Krüger, TO Meyer, JR Patterson, TK Pedlar, D Peterson, J Pivarski, D Riley, JL Rosner, AJ Sadoff, H Schwarthoff, MR Shepherd, WM Sun, JG Thayer, D Urner, T Wilksen, M Weinberger, SB Athar, P Avery, L Breva-Newell, V Potlia, H Stoeck, J Yelton, BI Eisenstein, GD Gollin, I Karliner, N Lowrey, P Naik, C Sedlack, M Selen, JJ Thaler, J Williams, KW Edwards, D Besson, KY Gao, DT Gong, Y Kubota, SZ Li, R Poling, AW Scott, A Smith, CJ Stepaniak, J Urheim, Z Metreveli, KK Seth, A Tomaradze, P Zweber, J Ernst, K Arms, E Eckhart, KK Gan, C Gwon, H Severini, P Skubic, DM Asner, SA Dytman, S Mehrabyan, JA Mueller, S Nam, V Savinov, GS Huang, DH Miller, V Pavlunin, B Sanghi, EI Shibata, IPJ Shipsey, GS Adams

Abstract:

We present the first evidence for the production of Υ(1D) states in the four-photon cascade, Υ(3S) →γχb(2P), χb(2P)→γΥ(1D), Υ(1D) →γχb(1P), χb(1P)→γΥ(1S) , followed by the Υ(1S) annihilation into e+e- or μ+μ-. The signal has a significance of 10.2 standard deviations. The measured product branching ratio for these five decays, (2.5±0.5±0.5)×10-5, is consistent with the theoretical estimates. The data are dominated by the production of one Υ(1D) state consistent with the J=2 assignment. Its mass is determined to be (10161.1±0.6±1.6) MeV, which is consistent with the predictions from potential models and lattice QCD calculations. We also searched for Υ(3S)→γχb(2P), χb(2P) →γΥ(1D), followed by either Υ(1D)→ηΥ(1S) or Υ(1D)→π+π-Υ(1S). We find no evidence for such decays and set upper limits on the product branching ratios.

Measurement of the polar-angle distribution of leptons from W boson decay as a function of the W transverse momentum in pp̄ collisions at √s=1.8 TeV

Physical Review D Particles Fields Gravitation and Cosmology 70:3 (2004) 1-32004

Authors:

D Acosta, T Affolder, MG Albrow, D Ambrose, D Amidei, K Anikeev, J Antos, G Apollinari, T Arisawa, A Artikov, W Ashmanskas, F Azfar, P Azzi-Bacchetta, N Bacchetta, H Bachacou, W Badgett, A Barbaro-Galtieri, VE Barnes, BA Barnett, S Baroiant, M Barone, G Bauer, F Bedeschi, S Behari, S Belforte, WH Bell, G Bellettini, J Bellinger, D Benjamin, A Beretvas, A Bhatti, M Binkley, D Bisello, M Bishai, RE Blair, C Blocker, K Bloom, B Blumenfeld, A Bocci, A Bodek, G Bolla, A Bolshov, D Bortoletto, J Boudreau, C Bromberg, E Brubaker, J Budagov, HS Budd, K Burkett, G Busetto, KL Byrum, S Cabrera, M Campbell, W Carithers, D Carlsmith, A Castro, D Cauz, A Cerri, L Cerrito, J Chapman, C Chen, YC Chen, M Chertok, G Chiarelli, G Chlachidze, F Chlebana, ML Chu, JY Chung, WH Chung, YS Chung, CI Ciobanu, AG Clark, M Coca, A Connolly, M Convery, J Conway, M Cordelli, J Cranshaw, R Culbertson, D Dagenhart, S D'Auria, P de Barbaro, S de Cecco, S Dell'Agnello, M Dell'Orso, S Demers, L Demortier, M Deninno, D de Pedis, PF Derwent, C Dionisi, JR Dittmann, A Dominguez, S Donati, M D'Onofrio, T Dorigo, N Eddy, R Erbacher, D Errede, S Errede

Abstract:

We present a measurement of the polar-angle distribution of leptons from W boson decay, as a function of the W transverse momentum. The measurement uses an 80±4 pb-1 sample of pp̄ collisions at √s = 1.8 TeV collected by the CDF detector and includes data from both the W→e+ν and W→μ+ν decay channels. We fit the W boson transverse mass distribution to a set of templates from a Monte Carlo event generator and detector simulation in several ranges of the W transverse momentum. The measurement agrees with the standard model expectation, whereby the ratio of longitudinally to transversely polarized W bosons, in the Collins-Soper W rest frame, increases with the W transverse momentum at a rate of approximately 15% per 10 GeV/c.