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An ultra-relativistic outflow from a neutron star accreting gas from a companion

(2004)

Authors:

Rob Fender, Kinwah Wu, Helen Johnston, Tasso Tzioumis, Peter Jonker, Ralph Spencer, Michiel van der Klis

Detection of a red supergiant progenitor star of a type II-plateau supernova

(2004)

Authors:

SJ Smartt, JR Maund, MA Hendry, CA Tout, GF Gilmore, S Mattila, CR Benn

The massive binary companion star to the progenitor of supernova 1993J

(2004)

Authors:

JR Maund, SJ Smartt, RP Kudritzki, Ph Podsiadlowski, GF Gilmore

Direct photon cross section with conversions at CDF

Physical Review D - Particles, Fields, Gravitation and Cosmology 70:7 (2004)

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 Barbaro, S Cecco, S Dell'Agnello, M Dell'Orso, S Demers, L Demortier, M Deninno, D 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 isolated direct photon cross section in [Formula Presented] collisions at [Formula Presented] and [Formula Presented] using data collected between 1994 and 1995 by the Collider Detector at Fermilab (CDF). The measurement is based on events where the photon converts into an electron-positron pair in the material of the inner detector, resulting in a two track event signature. To remove [Formula Presented] and [Formula Presented] events from the data we use a new background subtraction technique which takes advantage of the tracking information available in a photon conversion event. We find that the shape of the cross section as a function of photon [Formula Presented] is poorly described by next-to-leading-order QCD predictions, but agrees with previous CDF measurements. © 2004 The American Physical Society.

Heavy flavor properties of jets produced in pp̄ interactions at √s = 1.8 TeV

Physical Review D 69:7 (2004)

Authors:

D Acosta, D Ambrose, K Anikeev, J Antos, G Apollinari, T Arisawa, A Artikov, F Azfar, P Azzi-Bacchetta, N Bacchetta, VE Barnes, BA Barnett, M Barone, G Bauer, F Bedeschi, S Behari, S Belforte, WH Bell, G Bellettini, J Bellinger, A Beretvas, A Bhatti, D Bisello, C Blocker, B Blumenfeld, A Bocci, G Bolla, A Bolshov, D Bortoletto, J Budagov, HS Budd, K Burkett, G Busetto, S Cabrera, W Carithers, D Carlsmith, R Carosi, A Castro, D Cauz, A Cerri, C Chen, YC Chen, G Chiarelli, G Chlachidze, ML Chu, WH Chung, YS Chung, AG Clark, M Coca, M Convery, M Cordelli, J Cranshaw, D Dagenhart, S D'Auria, S Dell'Agnello, P de Barbaro, S de Cecco, M Dell'Orso, L Demortier, M Deninno, D de Pedis, C Dionisi, S Donati, M D'Onofrio, T Dorigo, R Eusebi, S Farrington, JP Fernandez, RD Field, I Fiori, A Foland, LR Flores-Castillo, M Franklin, J Friedman, I Furic, M Gallinaro, AF Garfinkel, E Gerstein, S Giagu, P Giannetti, K Giolo, M Giordani, P Giromini, V Glagolev, G Gomez, I Gorelov, AT Goshaw, K Goulianos, A Gresele, M Guenther, J Guimaraes da Costa, E Halkiadakis, C Hall, R Handler, F Happacher, K Hara, F Hartmann, K Hatakeyama, J Hauser, J Heinrich

Abstract:

We present a detailed examination of the heavy flavor properties of jets produced at the Fermilab Tevatron collider. The data set, collected with the Collider Detector at Fermilab, consists of events with two or more jets with transverse energy ET≥15 GeV and pseudorapidity |η|≤1.5. The heavy flavor content of the data set is enriched by requiring that at least one of the jets (lepton-jet) contains a lepton with a transverse momentum larger than 8 GeV/c. Jets containing hadrons with heavy flavor are selected via the identification of secondary vertices. The parton-level cross sections predicted by the HERWIG Monte Carlo generator program are tuned within theoretical and experimental uncertainties to reproduce the secondary-vertex rates in the data. The tuned simulation provides new information on the origin of the discrepancy between the bb̄ cross section measurements at the Tevatron and the next-to-leading order QCD prediction. We also compare the rate of away-jets (jets recoiling against the lepton-jet) containing a soft lepton (p T≥2 GeV/c) in the data to that in the tuned simulation. We find that this rate is larger than what is expected for the conventional production and semileptonic decay of pairs of hadrons with heavy flavor. © 2004 The American Physical Society.