Measurement of the top-quark mass with dilepton events selected using neuroevolution at CDF

Physical Review Letters 102:15 (2009)

Authors:

T Aaltonen, J Adelman, T Akimoto, MG Albrow, B Álvarez González, S Amerio, D Amidei, A Anastassov, A Annovi, J Antos, G Apollinari, A Apresyan, T Arisawa, A Artikov, W Ashmanskas, A Attal, A Aurisano, F Azfar, P Azzurri, W Badgett, A Barbaro-Galtieri, VE Barnes, BA Barnett, V Bartsch, G Bauer, PH Beauchemin, F Bedeschi, P Bednar, D Beecher, S Behari, G Bellettini, J Bellinger, D Benjamin, A Beretvas, J Beringer, A Bhatti, M Binkley, D Bisello, I Bizjak, RE Blair, C Blocker, B Blumenfeld, A Bocci, A Bodek, V Boisvert, G Bolla, D Bortoletto, J Boudreau, A Boveia, B Brau, A Bridgeman, L Brigliadori, C Bromberg, E Brubaker, J Budagov, HS Budd, S Budd, K Burkett, G Busetto, P Bussey, A Buzatu, KL Byrum, S Cabrera, C Calancha, M Campanelli, M Campbell, F Canelli, A Canepa, D Carlsmith, R Carosi, S Carrillo, S Carron, B Casal, M Casarsa, A Castro, P Catastini, D Cauz, V Cavaliere, M Cavalli-Sforza, A Cerri, L Cerrito, SH Chang, YC Chen, M Chertok, G Chiarelli, G Chlachidze, F Chlebana, K Cho, D Chokheli, JP Chou, G Choudalakis, SH Chuang, K Chung, WH Chung, YS Chung, CI Ciobanu, MA Ciocci, A Clark, D Clark, G Compostella

Abstract:

We report a measurement of the top-quark mass Mt in the dilepton decay channel tt̄→bl′+νl′b̄l-ν̄l. Events are selected with a neural network which has been directly optimized for statistical precision in top-quark mass using neuroevolution, a technique modeled on biological evolution. The top-quark mass is extracted from per-event probability densities that are formed by the convolution of leading order matrix elements and detector resolution functions. The joint probability is the product of the probability densities from 344 candidate events in 2.0fb-1 of pp̄ collisions collected with the CDF II detector, yielding a measurement of Mt=171.2±2.7(stat)±2.9(syst)GeV/c2. © 2009 The American Physical Society.

On the variation of black hole accretion disc radii as a function of state and accretion rate

(2009)

Authors:

C Cabanac, RP Fender, RJH Dunn, EG Koerding

Particle Physics and Astrophysics -- A whitepaper in response to a call to the Astronomy and Astrophysics Community from the Committee on Astro2010 for State of the Profession Position Papers

ArXiv 0904.0595 (2009)

Authors:

I Shipsey, L Buckley-Geer, P Burchat, D Burke, E Cheu, D Cinabro, K Honscheid, S Kahn, D Kirkby, B Meadows, R Schindler, J Thaler, W Wester

Abstract:

We discuss some of the key science questions that are bringing particle physicists and astrophysicists together, and comment on some of the cultural and funding issues that have arisen as these two communities become increasingly intertwined.

SN 1999ga: a low-luminosity linear type II supernova?

(2009)

Authors:

A Pastorello, RM Crockett, R Martin, SJ Smartt, G Altavilla, S Benetti, MT Botticella, E Cappellaro, S Mattila, JR Maund, SD Ryder, M Salvo, S Taubenberger, M Turatto

Dalitz plot analysis of Ds+→K+K-π+

Physical Review D - Particles, Fields, Gravitation and Cosmology 79:7 (2009)

Authors:

RE Mitchell, MR Shepherd, D Besson, TK Pedlar, J Xavier, D Cronin-Hennessy, KY Gao, J Hietala, Y Kubota, T Klein, R Poling, AW Scott, P Zweber, S Dobbs, Z Metreveli, KK Seth, BJY Tan, A Tomaradze, J Libby, L Martin, A Powell, C Thomas, G Wilkinson, H Mendez, JY Ge, DH Miller, IPJ Shipsey, B Xin, GS Adams, D Hu, B Moziak, J Napolitano, KM Ecklund, Q He, J Insler, H Muramatsu, CS Park, EH Thorndike, F Yang, M Artuso, S Blusk, S Khalil, R Mountain, K Randrianarivony, N Sultana, T Skwarnicki, S Stone, JC Wang, LM Zhang, G Bonvicini, D Cinabro, M Dubrovin, A Lincoln, MJ Smith, P Zhou, J Zhu, P Naik, J Rademacker, DM Asner, KW Edwards, J Reed, AN Robichaud, G Tatishvili, EJ White, RA Briere, H Vogel, PUE Onyisi, JL Rosner, JP Alexander, DG Cassel, JE Duboscq, R Ehrlich, L Fields, L Gibbons, R Gray, SW Gray, DL Hartill, BK Heltsley, D Hertz, JM Hunt, J Kandaswamy, DL Kreinick, VE Kuznetsov, J Ledoux, H Mahlke-Krüger, JR Patterson, D Peterson, D Riley, A Ryd, AJ Sadoff, X Shi, S Stroiney, WM Sun, T Wilksen, J Yelton, P Rubin, N Lowrey, S Mehrabyan, M Selen, J Wiss

Abstract:

We perform a Dalitz plot analysis of the decay Ds+→K+K-π+ with the CLEO-c data set of 586pb-1 of e+e- collisions accumulated at s=4.17GeV. This corresponds to about 0.57×106 Ds±Ds* pairs from which we select 14400 candidates with a background of roughly 15%. In contrast to previous measurements we find good agreement with our data only by including an additional f0(1370)π+ contribution. We measure the magnitude, phase, and fit fraction of K*(892)0K+, (1020)π+, K0*(1430)K+, f0(980)π+, f0(1710)π+, and f0(1370)π+ contributions and limit the possible contributions of other KK and Kπ resonances that could appear in this decay. © 2009 The American Physical Society.