Skip to main content
Home
Department Of Physics text logo
  • Research
    • Our research
    • Our research groups
    • Our research in action
    • Research funding support
    • Summer internships for undergraduates
  • Study
    • Undergraduates
    • Postgraduates
  • Engage
    • For alumni
    • For business
    • For schools
    • For the public
Menu
Insertion of STC into TRT at the Department of Physics, Oxford
Credit: CERN

Professor Chris Hays

Professor of Physics

Research theme

  • Fundamental particles and interactions

Sub department

  • Particle Physics

Research groups

  • ATLAS
Chris.Hays@physics.ox.ac.uk
Telephone: 01865 (2)73355
Denys Wilkinson Building, room 675
  • About
  • Research
  • Publications

Measurement of the moments of the hadronic invariant mass distribution in semileptonic B decays

Physical Review D - Particles, Fields, Gravitation and Cosmology 71:5 (2005) 1-9

Authors:

D Acosta, J Adelman, T Affolder, T Akimoto, MG Albrow, D Ambrose, S Amerio, D Amidei, A Anastassov, K Anikeev, A Annovi, J Antos, M Aoki, G Apollinari, T Arisawa, JF Arguin, A Artikov, W Ashmanskas, A Attal, F Azfar, P Azzi-Bacchetta, N Bacchetta, H Bachacou, W Badgett, A Barbaro-Galtieri, GJ Barker, VE Barnes, BA Barnett, S Baroiant, M Barone, G Bauer, F Bedeschi, S Behari, S Belforte, G Bellettini, J Bellinger, E Ben-Haim, 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, PSL Booth, D Bortoletto, J Boudreau, S Bourov, B Brau, C Bromberg, E Brubaker, J Budagov, HS Budd, K Burkett, G Busetto, P Bussey, KL Byrum, S Cabrera, M Campanelli, M Campbell, A Canepa, M Casarsa, D Carlsmith, S Carron, R Carosi, M Cavalli-Sforza, A Castro, P Catastini, D Cauz, A Cerri, L Cerrito, J Chapman, C Chen, YC Chen, M Chertok, G Chiarelli, G Chlachidze, F Chlebana, I Cho, K Cho, D Chokheli, JP Chou, ML Chu, S Chuang, JY Chung, WH Chung, YS Chung, CI Ciobanu, MA Ciocci, AG Clark, D Clark, M Coca, A Connolly

Abstract:

Using 180 pb -1 of data collected with the CDF II detector at the Tevatron, we measure the first two moments of the hadronic invariant mass-squared distribution in charmed semileptonic B decays. From these we determine the nonperturbative Heavy Quark Effective Theory parameters Λ and λ 1 used to relate the B meson semileptonic branching ratio to the CKM matrix element |V cb|. For a minimum lepton momentum of 0.7 GeV/c in the B rest frame we measure the first two moments of the D** → D (*)π component to be 〈m D**2〉 = (5.83 ± 0.16 stat ± 0.08 syst) GeV 2/c 4 and 〈(m D**2 - 〈m D**2〉) 2〉 = (1.30 ± 0.69 stat ± 0.22 syst) GeV 4/c 8. Combining these with the discrete mass terms from the D and D* mesons, we find the total moments to be 〈M Ξc2〉 - m̄ D2 = (0.467 ± 0.038 stat ± 0.068 syst GeV 2/c 4 and 〈(M Ξc2 - 〈M Ξc2〉) 2〉 = (1.05 ± 0.26 stat ± 0.13 syst) GeV 4/c 8, where m̄ D is the spin-averaged D mass. The systematic error is dominated by the uncertainties in the world-average branching ratios used to combine the D, D*, and D** contributions. The analysis makes no assumptions about the shape or resonant structure of the D** → D (*)π invariant mass distribution. © 2005 The American Physical Society.
More details from the publisher

Measurement of the tt̄ production cross section in pp̄ collisions at √s = 1.96 TeV using lepton + jets events with secondary vertex b -tagging

Physical Review D - Particles, Fields, Gravitation and Cosmology 71:5 (2005) 1-28

Authors:

D Acosta, J Adelman, T Affolder, T Akimoto, MG Albrow, D Ambrose, S Amerio, D Amidei, A Anastassov, K Anikeev, A Annovi, J Antos, M Aoki, G Apollinari, T Arisawa, JF Arguin, A Artikov, W Ashmanskas, A Attal, F Azfar, P Azzi-Bacchetta, N Bacchetta, H Bachacou, W Badgett, A Barbaro-Galtieri, GJ Barker, VE Barnes, BA Barnett, S Baroiant, M Barone, G Bauer, F Bedeschi, S Behari, S Belforte, G Bellettini, J Bellinger, E Ben-Haim, 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, PSL Booth, D Bortoletto, J Boudreau, S Bourov, C Bromberg, E Brubaker, J Budagov, HS Budd, K Burkett, G Busetto, P Bussey, KL Byrum, S Cabrera, M Campanelli, M Campbell, A Canepa, M Casarsa, D Carlsmith, S Carron, R Carosi, M Cavalli-Sforza, A Castro, P Catastini, D Cauz, A Cerri, C Cerri, L Cerrito, J Chapman, C Chen, YC Chen, M Chertok, G Chiarelli, G Chlachidze, F Chlebana, I Cho, K Cho, D Chokheli, ML Chu, S Chuang, JY Chung, WH Chung, YS Chung, CI Ciobanu, MA Ciocci, AG Clark, D Clark, M Coca, A Connolly, M Convery

Abstract:

We present a measurement of the tt̄ production cross section using events with one charged lepton and jets from pp̄ collisions at a center-of-mass energy of 1.96 TeV. In these events, heavy flavor quarks from top quark decay are identified with a secondary vertex tagging algorithm. From 162 pb-1 of data collected by the Collider Detector at Fermilab, a total of 48 candidate events are selected, where 13.5 ± 1.8 events are expected from background contributions. We measure a tt̄ production cross section of 5.6-1.1+1.2(stat.)-0.6+0.9(syst.) pb. © 2005 The American Physical Society.
More details from the publisher

Measurement of the Bs0 lifetime in the exclusive decay channel Bs0 → J/ψφ

Physical Review Letters 94:4 (2005)

Authors:

VM Abazov, B Abbott, M Abolins, BS Acharya, DL Adams, M Adams, T Adams, M Agelou, JL Agram, SN Ahmed, SH Ahn, GD Alexeev, G Alkhazov, A Alton, G Alverson, GA Alves, M Anastasoaie, S Anderson, B Andrieu, Y Arnoud, A Askew, B Åsman, O Atramentov, C Autermann, C Avila, L Babukhadia, TC Bacon, F Badaud, A Baden, S Baffioni, B Baldin, PW Balm, S Banerjee, E Barberis, P Bargassa, P Baringer, C Barnes, J Barreto, JF Bartlett, U Bassler, D Bauer, A Bean, S Beauceron, F Beaudette, M Begel, A Bellavance, SB Beri, G Bernardi, R Bernhard, I Bertram, M Besancon, A Besson, R Beuselinck, VA Bezzubov, PC Bhat, V Bhatnagar, M Bhattacharjee, M Binder, A Bischoff, KM Black, I Blackler, G Blazey, F Blekman, S Blessing, D Bloch, U Blumenschein, A Boehnlein, O Boeriu, TA Bolton, P Bonamy, F Borcherding, G Borissov, K Bos, T Bose, C Boswell, A Brandt, G Briskin, R Brock, G Brooijmans, A Bross, NJ Buchanan, D Buchholz, M Buehler, V Buescher, S Burdin, TH Burnett, E Busato, JM Butler, J Bystricky, F Canelli, W Carvalho, BCK Casey, D Casey, NM Cason, H Castilla-Valdez, S Chakrabarti, D Chakraborty, KM Chan, A Chandra, D Chapin

Abstract:

Using the exclusive decay Bs0 → J/ψ (μ+μ-)φ (K+K-), we report the most precise single measurement of the Bs0 lifetime. The data sample corresponds to an integrated luminosity of approximately 220 pb-1 collected with the DO detector at the Fermilab Tevatron Collider in 2002-2004. We reconstruct 337 signal candidates, from which we extract the Bs0 lifetime, τ(Bs0) = 1.444-0.090+0.098(stat) ± 0.020(sys) ps. We also report a measurement for the lifetime of the B0 meson using the exclusive decay B0 → J/ψ(μ+μ-) K*0(&92)(K+π-). We reconstruct 1370 signal candidates, obtaining τ(B0) = 1.473 -0.050+0.052(stat)±0.023(sys) ps, and the ratio of lifetimes, τ(Bs0)/τ(B0) = 0.980 -0.0.710.076(stat) ± 0.003(sys). © 2005 The American Physical Society.
More details from the publisher
More details

Search for supersymmetry with gauge-mediated breaking in diphoton events at D0

Physical Review Letters 94:4 (2005)

Authors:

VM Abazov, B Abbott, M Abolins, BS Acharya, DL Adams, M Adams, T Adams, M Agelou, JL Agram, SN Ahmed, SH Ahn, GD Alexeev, G Alkhazov, A Alton, G Alverson, GA Alves, S Anderson, B Andrieu, Y Arnoud, A Askew, B Åsman, O Atramentov, C Autermann, C Avila, L Babukhadia, TC Bacon, A Baden, S Baffioni, B Baldin, PW Balm, S Banerjee, E Barberis, P Bargassa, P Baringer, C Barnes, J Barreto, JF Bartlett, U Bassler, D Bauer, A Bean, S Beauceron, F Beaudette, M Begel, A Bellavance, SB Beri, G Bernardi, R Bernhard, I Bertram, M Besançon, A Besson, R Beuselinck, VA Bezzubov, PC Bhat, V Bhatnagar, M Bhattacharjee, M Binder, A Bischoff, KM Black, I Blackler, G Blazey, F Blekman, D Bloch, U Blumenschein, A Boehnlein, O Boeriu, TA Bolton, P Bonamy, F Borcherding, G Borissov, K Bos, T Bose, C Boswell, A Brandt, G Briskin, R Brock, G Brooijmans, A Bross, NJ Buchanan, D Buchholz, M Buehler, V Buescher, S Burdin, TH Burnett, E Busato, JM Butler, J Bystricky, F Canelli, W Carvalho, BCK Casey, D Casey, NM Cason, H Castilla-Valdez, S Chakrabarti, D Chakraborty, KM Chan, A Chandra, D Chapin, F Charles, E Cheu, L Chevalier

Abstract:

We report the results of a search for supersymmetry (SUSY) with gauge-mediated breaking in the missing transverse energy distribution of inclusive diphoton events using 263 pb-1 of data collected by the DO experiment at the Fermilab Tevatron Collider in 2002-2004. No excess is observed above the background expected from standard model processes, and lower limits on the masses of the lightest neutralino and chargino of about 108 and 195 GeV, respectively, are set at the 95% confidence level. These are the most stringent limits to date for models with gauge-mediated SUSY breaking with a short-lived neutralino as the next-to-lightest SUSY particle. © 2005 The American Physical.
More details from the publisher
More details

Measurement of the J/ψ meson and b-hadron production cross sections in pp̄ collisions at √s = 1960 GeV

Physical Review D - Particles, Fields, Gravitation and Cosmology 71:3 (2005) 032001-1-032001-26

Authors:

DE Acosta, J Adelman, T Affolder, T Akimoto, MG Albrow, DJ Ambrose, S Amerio, D Amidei, A Anastassov, K Anikeev, A Annovi, J Antoš, M Aoki, G Apollinari, T Arisawa, JF Arguin, AM Artikov, WJ Ashmanskas, A Attal, F Azfar, P Azzi-Bacchetta, N Bacchetta, H Bachacou, WF Badgett, AA Barbaro-Galtieri, GJ Barker, VE Barnes, BA Barnett, S Baroiant, M Barone, G Bauer, F Bedeschi, S Behari, S Belforte, G Bellettini, JN Bellinger, E Ben-Haim, DP Benjamin, A Beretvas, AA Bhatti, ME Binkley, DB Bisello, MR Bishai, RE Blair, CA Blocker, K Bloom, BJ Blumenfeld, A Bocci, A Bodek, G Bolla, AA Bolshov, PSL Boóth, D Bortoletto, JF Boudreau, S Bourov, BP Brau, CM Bromberg, EM Brubaker, JA Budagov, HS Budd, K Burkett, G Busetto, PJ Bussey, KL Byrum, S Cabrera, M Campanelli, MK Campbell, A Canepa, M Casarsa, D Carlsmith, S Carron, R Carosi, MC Cavalli-Sforza, AJ Castro, PL Catastini, D Cauz, A Cerri, L Cerrito, JW Chapman, C Chen, Y Chen, MB Chertok, G Chiarelli, GA Chlachidze, FS Chlebana, L Cho, K Cho, D Chokheli, J Chou, M Chu, SHS Chuang, J Chung, WH Chung, Y Chung, CI Ciobanu, MA Ciocci, AG Clark, DE Clark, MN Coca, A Connolly, ME Convery, JS Conway, BD Cooper, M Cordelli, G Cortiana, J Cranshaw, J Cuevas, RL Culbertson, CA Currat, D Cyr, DW Dagenhart, S Da Ronco, S D'Auria, P De Barbaro, SD De Cecco, G De Lentdecker, S Dell'Agnello, M Dell'Orso, SM Demers, L Demortier, MM Deninno, D De Pedis, PF Derwent, C Dionisi, JR Dittmann, C Dörr, P Doksus, A Domínguez, S Donati, M Donegà, J Donini, M D'Onofrio, T Dorigo, DrollingerV, K Ebina, N Eddy, JE Ehlers, RP Ely, RD Erbacher, M Erdmann, D Errede, SM Errede, R Eusebi, H Fang, SM Farrington, I Fedorko, WT Fedorko, RG Feild, M Feindt, JP Fernández, C Ferretti, RD Field, GP Flanagan, BL Flaugher, LR Flores-Castillo, AD Foland, S Forrester, GW Foster, MEB Franklin, JC Freeman, Y Fujii, IK Furić, A Gajjar, AA Gallas, J Galyardt, M Gallinaro, M Garcia-Sciveres, AF Garfinkel, C Gay, HK Gerberich, DW Gerdes, EA Gerchtein, S Giagu, P Giannetti, AJ Gibson, KR Gibson, C Ginsburg, K Giolo, MP Giordani, M Giunta, GA Giurgiu, VV Glagolev, DA Glenzinskí, MS Gold, N Goldschmidt, DJ Goldstein, J Goldstein, G Gómez, G Gómez-Ceballos, MV Goncharov, O González, IV Gorelov, AT Goshaw, YN Gotra, K Goulianos, A Gresele, M Griffiths, C Grosso-Pilcher, U Grundler, M Guenther, JB Guimarães Da Costa, V Haber, K Hahn, SR Hahn, E Halkiadakis, A Hamilton, B Han, R Handler, F Happacher, K Hara, MF Hare, RF Harr, RM Harris, FX Hartmann, K Hatakeyama, J Hauser, CP Hays, HaywardH, EM Heider, B Heinemann, JG Heinrich, M Hennecke, M Herndon, CS Hill, D Hirschbuehl, A Höcker, D HoffmanK, A Holloway, S Hou, MA Houlden, BT Huffman, Y Huang, RE Hughes, JW Huston, K Ikado, JR Incandela, G Introzzi, M Iori, Y Ishizawa, C Ìşsever, A Ivanov, Y Iwata, B Iyutin, EB James, D Jang, J Jarrell, DT Jeans, HB Jensen, E Jeon, MK Jones, K Joo, S Jun, TR Junk, T Kamon, J Kang, MK Ünel, PE Karchin, SN Kartal, Y Kato, Y Kemp, RD Kephart, U Kerzel, V Khotilovich, BJ Kilminster, DH Kim, H Kim, J Kim, M Kim, M Kim, SB Kim, S Kim, T Kim, Y Kim, BT King, MH Kirby, LE Kirsch, S Klimenko, B Knuteson, B Ko, H Kobayashi, P Koehn, D Kong, K Kondo, J Königsberg, K Kordas, A Korn, AV Korytov, KA Kotelnikov, AV Kotwal, AI Kovalev, JA Kraus, IT Kravchenko, AE Kreymer, J Kroll, MC Kruse, V Krutelyov, SE Kuhlmann, S Kwang, AT Laasanen, S Lai, SS Lami, S Lammel, JM Lancaster, MA Lancaster, RL Lander, K Lannon, A Lath, G Latino, RTA Lauhakangas, I Lazzizzera, Y Le, C Lecci, TJ LeCompte, J Lee, J Lee, S Lee, RP Lefèvre, NT Leonardo, S Leone, SL Levy, JD Lewis, K Li, CS Lin, CSS Lin, MA Lindgren, TM Liss, A Lister, DO Litvintsev, T Liu, Y Liu, NS Lockyer, AY Loginov, M Loreti, PF Loverre, R Lu, D Lucchesi, PJ Lujan, PT Lukens, GA Lungu, LPR Lyons, JEA Lys, R Lysak, DM MacQueen, RL Madrak, K Maeshima, P Maksimović, L Malferrari, G Manca, RM Mǎrginean, C Marino, AJ Martin, MS Martin, VJ Martin, MI Martínez, T Maruyama, H Matsunaga, M Mattson, P Mazzanti, KS McFarland, D McGivern, PM McIntyre, PA McNamara, R NcNulty, A Mehta, S Menzemer, A Menzione, P Merkel, C Mesropian, AM Messina, T Miao, N Miladinovic, LM Miller, RJD Miller, JS Miller, R Miquel, S Miscetti, GV Mitselmakher, A Miyamoto, Y Miyazaki, N Moggi, B Mohr, RW Moore, MJ Morello, PAM Fernández, A Mukherjee, M Mulhearn, TA Müller, R Mumford, A Munar, PA Murat, JM Nachtman, S Nahn, I Nakamura, I Nakano, A Napier, R Napora, DV Naumov, V Necula, F Niell, JA Nielsen, CA Nelson, TK Nelson, C Neu, MS Neubauer, CB Newman-Holmes, TS Nigmanov, LJ Nodulman, O Norniella, K Oesterberg, T Ogawa, SH Oh, Y Oh, T Ohsugi, T Okusawa, RGC Oldeman, R Orava, W Orejudos, CE Pagliarone, E Palencia, R Paoletti, VK Papadimitriou, S Pashapour, JF Patrick, G Pauletta, MG Paulini, T Pauly, C Paus, DE Pellett, A Penzo, TJ Phillips, GM Piacentino, J Piedra, KT Pitts, CL Plager, A Pompoš, LG Pondrom, G Pope, X Portell, O Poukhov, F Prakoshyn, T Pratt, A Pronko, J Proudfoot, F Ptohos, G Punzi, JH Rademacker, MA Rahaman, A Rakitine, S Rappoccio, FD Ratnikov, H Ray, B Reisert, V Rekovic, PB Renton, M Rescigno, F Rimondi, K Rinnert, L Ristori, WJ Robertson, A Robson, T Rodrigo, S Rolli, L Rosenson, RM Roser, R Rossin, C Rott, JS Russ, VL Rusu, A Ruiz-Jimeno, DT Ryan, HMT Saarikko, S Sabik, AN Safonov, RDS St Denis, WK Sakumoto, G Salamanna, DP Saltzberg, CAS Sánchez, A Sansoni, L Santi, S Sarkar, K Sato, P Savard, A Savoy-Navarro, P Schlabach, EE Schmidt, MP Schmidt, M Schmitt, L Scodellaro, A Scribano, F Scuri, A Sedov, SC Seidel, Y Seiya, F Semeria, L Sexton-Kennedy, I Sfiligoi, MD Shapiro, TG Shears, PF Shepard, D Sherman, M Shimojima, MJ Shochet, Y Shon, I Shreyber, A Sidoti, JL Siegrist, M Šiket, AF Sill, PK Sinervo, AN Sisakyan, A Skiba, AJ Slaughter, K Śliwa, DV Smirnov, JRH Smith, FD Snider, R Snihur, A Soha, SV Somalwar, J Spalding, MA Spezziga, L Spiegel, F Spinella, M Spiropulu, P Squillacioti, H Stadie, B Stelzer, O Stelzer-Chilton, J Strologas, DD Stuart, AI Sukhanov, KCTO Sumorok, H Sun, T Suzuki, AC Taffard, R Tafirout, SF Takach, H Takano, R Takashima, Y Takeuchi, K Takikawa, M Tanaka, R Tanaka, N Tanimoto, S Tapprogge, M Tecchio, P Teng, K Terashi, RJ Tesarek, S Tether, J Thom, AS Thompson, EJ Thomson, PL Tipton, V Tiwari, SM Tkaczyk, D Toback, K Tollefson, T Tomura, D Tonelli, M Tönnesmann, SD Torre, D Torretta, S Tourneur, W Trischuk, J Tseng, R Tsuchiya, S Tsuno, D Tsybychev, N Turini, MF Turner, F Ukegawa, T Unverhau, S Uozumi, D Usynin, L Vacavant, A Vaiciulis, AV Varganov, ES Vataga, S Vejcik, GV Velev, V Veszprémi, G Veramendi, T Vickey, RA Vidal, I Vila, R Vilar, I Vollrath, I Volobouev, M Von Der Mey, PD Wágner, RG Wagner, RL Wagner, W Wagner, RS Wallny, T Walter, T Yamashita, K Yamamoto, Z Wan, M Wang, S Wang, A Warburton, BR Ward, S Waschke, DS Waters, TL Watts, MS Weber, WC Wester, B Whitehouse, AB Wicklund, EJ Wicklund, HH Williams, PJ Wilson, BL Winer, P Wittich, SA Wolbers, CE Wolfe, MW Wolter, M Worcester, SD Worm, TR Wright, X Wu, F Würthwein, AC Wyatt, A Yagil, C Yang, U Yang, W Yao, GP Yeh, K Yi, J Yoh, PS Yoon, K Yorita, T Yoshida, I Yu, S Yu, Z Yu, JC Yun, L Zanello, AM Zanetti, I Zaw, F Zetti, J Zhou, A Žsenei, S Zucchelli

Abstract:

We present a new measurement of the inclusive and differential production cross sections of J/ψ mesons and b hadrons in proton-antiproton collisions at √s = 1960 GeV. The data correspond to an integrated luminosity of 39.7 pb-1 collected by the CDF run II detector. We find the integrated cross section for inclusive J/ψ production for all transverse momenta from 0 to 20 GeV/c in the rapidity range |y| < 0.6 to be 4.08 ± 0.02(Stat)-0.33 +0.36(syst) μb. We separate the fraction of J/ψ events from the decay of the long-lived b hadrons using the lifetime distribution in all events with pT(J/ψ) > 1.25 GeV/c. We find the total cross section for b hadrons, including both hadrons and antihadrons, decaying to J/ψ with transverse momenta greater than 1.25 GeV/c in the rapidity range |y(J/ψ)| < 0.6 is 0.330 ± 0.005(stat) -0.033 +0.036(syst) μb. Using a Monte Carlo simulation of the decay kinematics of b hadrons to all final states containing a J/ψ, we extract the first measurement of the total single b-hadron cross section down to zero transverse momentum at √s = 1960 GeV. We find the total single b-hadron cross section integrated over all transverse momenta for b hadrons in the rapidity range |y| < 0.6 to be 17.6 ± 0.4(stat) -2.3 +2.5(syst) μb. © 2005 The American Physical Society.
More details from the publisher

Pagination

  • First page First
  • Previous page Prev
  • …
  • Page 393
  • Page 394
  • Page 395
  • Page 396
  • Current page 397
  • Page 398
  • Page 399
  • Page 400
  • Page 401
  • …
  • Next page Next
  • Last page Last

Footer Menu

  • Contact us
  • Giving to the Dept of Physics
  • Work with us
  • Media

User account menu

  • Log in

Follow us

FIND US

Clarendon Laboratory,

Parks Road,

Oxford,

OX1 3PU

CONTACT US

Tel: +44(0)1865272200

University of Oxfrod logo Department Of Physics text logo
IOP Juno Champion logo Athena Swan Silver Award logo

© University of Oxford - Department of Physics

Cookies | Privacy policy | Accessibility statement

Built by: Versantus

  • Home
  • Research
  • Study
  • Engage
  • Our people
  • News & Comment
  • Events
  • Our facilities & services
  • About us
  • Current students
  • Staff intranet