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Soft and hard interactions in pp̄ collisions at √s=1800 and 630 GeV

Physical Review D Particles Fields Gravitation and Cosmology 65:7 A (2002) 720051-7200512

Authors:

D Acosta, T Affolder, H Akimoto, MG Albrow, P Amaral, D Ambrose, D Amidei, K Anikeev, J Antos, G Apollinari, T Arisawa, A Artikov, T Asakawa, W Ashmanskas, F Azfar, P Azzi-Bacchetta, N Bacchetta, H Bachacou, S Bailey, P de Barbaro, A Barbaro-Galtieri, VE Barnes, BA Barnett, S Baroiant, M Barone, G Bauer, F Bedeschi, S Belforte, WH Bell, G Bellettini, J Bellinger, D Benjamin, J Bensinger, A Beretvas, JP Berge, J Berryhill, A Bhatti, M Binkley, D Bisello, M Bishai, RE Blair, C Blocker, K Bloom, B Blumenfeld, SR Blusk, A Bocci, A Bodek, G Bolla, Y Bonushkin, D Bortoletto, J Boudreau, A Brandl, S van den Brink, C Bromberg, M Brozovic, E Brubaker, N Bruner, E Buckley-Geer, J Budagov, HS Budd, K Burkett, G Busetto, A Byon-Wagner, KL Byrum, S Cabrera, P Calafiura, M Campbell, W Carithers, J Carlson, D Carlsmith, W Caskey, A Castro, D Cauz, A Cerri, AW Chan, PS Chang, PT Chang, J Chapman, C Chen, YC Chen, MT Cheng, M Chertok, G Chiarelli, I Chirikov-Zorin, G Chlachidze, F Chlebana, L Christofek, ML Chu, JY Chung, YS Chung, CI Ciobanu, AG Clark, AP Colijn, A Connolly, M Convery, J Conway, M Cordelli, J Cranshaw, R Culbertson, D Dagenhart

Abstract:

We present a study of pp̄ of collisions at √s = 1800 and 630 GeV collected using a minimum bias trigger by the CDF experiment in which the data set is divided into two classes corresponding to "soft" and "hard" interactions. For each subsample, the analysis includes measurements of the multiplicity, transverse momentum (PT) spectrum, and the average PT and event-by-event PT dispersion as a function of multiplicity. A comparison of results shows distinct differences in the behavior of the two samples as a function of the center of mass (c.m.) energy. We find evidence that the properties of the soft sample are invariant as a function of c.m. energy.

Measurement of B → K*γ branching fractions and charge asymmetries

Physical Review Letters 88:10 (2002) 1018051-1018057

Authors:

B Aubert, D Boutigny, JM Gaillard, A Hicheur, Y Karyotakis, JP Lees, P Robbe, V Tisserand, A Palano, GP Chen, JC Chen, ND Qi, G Rong, P Wang, YS Zhu, G Eigen, PL Reinertsen, B Stugu, B Abbott, GS Abrams, AW Borgland, AB Breon, DN Brown, J Button-Shafer, RN Cahn, AR Clark, MS Gill, AV Gritsan, Y Groysman, RG Jacobsen, RW Kadel, J Kadyk, LT Kerth, S Kluth, YG Kolomensky, JF Kral, C LeClerc, ME Levi, T Liu, G Lynch, AB Meyer, M Momayezi, PJ Oddone, A Perazzo, M Pripstein, NA Roe, A Romosan, MT Ronan, VG Shelkov, AV Telnov, WA Wenzel, MS Zisman, PG Bright-Thomas, TJ Harrison, CM Hawkes, DJ Knowles, SW O'Neale, RC Penny, AT Watson, NK Watson, T Deppermann, K Goetzen, H Koch, J Krug, M Kunze, B Lewandowski, K Peters, H Schmuecker, M Steinke, JC Andress, NR Barlow, W Bhimji, N Chevalier, PJ Clark, WN Cottingham, N de Groot, N Dyce, B Foster, JD McFall, D Wallom, FF Wilson, K Abe, C Hearty, TS Mattison, JA McKenna, D Thiessen, S Jolly, AK McKemey, J Tinslay, VE Blinov, AD Bukin, DA Bukin, AR Buzykaev, VB Golubev, VN Ivanchenko, AA Korol, EA Kravchenko, AP Onuchin, AA Salnikov, SI Serednyakov

Abstract:

The branching fraction of the exclusive decays B0 → K*0γ and B+ → K*+γ measured from a sample of BB̄ decays collected with the BABAR detector at the PEP-II asymetric e+e- collider was discussed. It was found that the weighted average of the measured CP-violating charged asymmetries was Acp(B → K*γ) = -0.044 + 0.076 (stat) ± 0.012 (syst). The results showed the CP-violating charge asymmetry to be constrained to -0.170 < Acp(B → K*γ) < 0.082 at 90% C.L.

Dijet production in neutral current deep inelastic scattering at HERA

European Physical Journal C 23:1 (2002) 13-27

Authors:

S Chekanov, M Derrick, D Krakauer, S Magill, B Musgrave, A Pellegrino, J Repond, R Yoshida, MCK Mattingly, P Antonioli, G Bari, M Basile, L Bellagamba, D Boscherini, A Bruni, G Bruni, G Cara Romeo, L Cifarelli, F Cindolo, A Contin, M Corradi, S de Pasquale, P Giusti, G Iacobucci, G Levi, A Margotti, T Massam, R Nania, F Palmonari, A Pesci, G Sartorelli, A Zichichi, G Aghuzumtsyan, I Brock, S Goers, H Hartmann, E Hilger, P Irrgang, HP Jakob, A Kappes, UF Katz, R Kerger, O Kind, E Paul, J Rautenberg, H Schnurbusch, A Stifutkin, J Tandler, KC Voss, A Weber, H Wieber, DS Bailey, NH Brook, JE Cole, B Foster, GP Heath, HF Heath, S Robins, E Rodrigues, J Scott, RJ Tapper, M Wing, M Capua, A Mastroberardino, M Schioppa, G Susinno, HY Jeoung, JY Kim, JH Lee, IT Lim, KJ Ma, MY Pac, A Caldwell, M Helbich, X Liu, B Mellado, S Paganis, WB Schmidke, F Sciulli, J Chwastowski, A Eskreys, J Figiel, K Klimek, K Olkiewicz, MB Przybycień, P Stopa, L Zawiejski, B Bednarek, I Grabowska-Bold, K Jeleń, D Kisielewska, AM Kowal, M Kowal, T Kowalski, B Mindur, E Rulikowska-Zarebska, L Suszycki, D Szuba, J Szuba, A Kotanński

Abstract:

Dijet cross sections in neutral current deep inelastic ep scattering have been measured in the range 10 < Q2 < 104 GeV 2 with the ZEUS detector at HERA using an integrated luminosity of 38.4 pb-1. The cross sections, measured in the Breit frame using the kT jet algorithm, are compared with next-to-leading-order perturbative QCD calculations using proton parton distribution functions. The uncertainties of the QCD calculations have been studied. The predictions are in reasonable agreement with the measured cross sections over the entire kinematic range.

Searches for new physics in events with a photon and b-quark jet at CDF

Physical Review D Particles Fields Gravitation and Cosmology 65:5 (2002) 520061-5200622

Authors:

T Affolder, H Akimoto, A Akopian, MG Albrow, P Amaral, D Amidei, K Anikeev, J Antos, G Apollinari, T Arisawa, A Artikov, T Asakawa, W Ashmanskas, F Azfar, P Azzi-Bacchetta, N Bacchetta, H Bachacou, S Bailey, P de Barbaro, A Barbaro-Galtieri, VE Barnes, BA Barnett, S Baroiant, M Barone, G Bauer, F Bedeschi, S Belforte, WH Bell, G Bellettini, J Bellinger, D Benjamin, J Bensinger, A Beretvas, JP Berge, J Berryhill, A Bhatti, M Binkley, D Bisello, M Bishai, RE Blair, C Blocker, K Bloom, B Blumenfeld, SR Blusk, A Bocci, A Bodek, W Bokhari, G Bolla, Y Bonushkin, D Bortoletto, J Boudreau, A Brandl, S van den Brink, C Bromberg, M Brozovic, E Brubaker, N Bruner, E Buckley-Geer, J Budagov, HS Budd, K Burkett, G Busetto, A Byon-Wagner, KL Byrum, S Cabrera, P Calafiura, M Campbell, W Carithers, J Carlson, D Carlsmith, W Caskey, A Castro, D Cauz, A Cerri, AW Chan, PS Chang, PT Chang, J Chapman, C Chen, YC Chen, MT Cheng, M Chertok, G Chiarelli, I Chirikov-Zorin, G Chlachidze, F Chlebana, L Christofek, ML Chu, YS Chung, CI Ciobanu, AG Clark, A Connolly, J Conway, M Cordelli, J Cranshaw, R Cropp, R Culbertson, D Dagenhart, S D'Auria, F DeJongh

Abstract:

We have searched for evidence of physics beyond the standard model in events that include an energetic photon and an energetic b-quark jet, produced in 85 pb-1 of p̄p collisions at 1.8 TeV at the Tevatron Collider at Fermilab. This signature, containing at least one gauge boson and a third-generation quark, could arise in the production and decay of a pair of new particles, such as those predicted by supersymmetry, leading to a production rate exceeding standard model predictions. We also search these events for anomalous production of missing transverse energy, additional jets and leptons (e, μ, and τ), and additional b quarks. We find no evidence for any anomalous production of γb or γb + X events. We present limits on two supersymmetric models: a model where the photon is produced in the decay χ̃20→ γχ̃10, and a model where the photon is produced in the neutralino decay into the gravitino LSP, χ̃10→ γG̃. We also present our limits in a model-independent form and test methods of applying model-independent limits.

51ÁÔÆæÈë¿Ú of the heavy flavor content of jets produced in association with W bosons in ppÌ„ collisions at √s=1.8TeV

Physical Review D - Particles, Fields, Gravitation and Cosmology 65:5 (2002) 520071-5200726

Authors:

D Acosta, T Affolder, H Akimoto, A Akopian, P Amaral, D Ambrose, D Amidei, K Anikeev, J Antos, G Apollinari, T Arisawa, A Artikov, T Asakawa, W Ashmanskas, F Azfar, P Azzi-Bacchetta, N Bacchetta, H Bachacou, S Bailey, P de Barbaro, A Barbaro-Galtieri, VE Barnes, BA Barnett, S Baroiant, M Barone, G Bauer, F Bedeschi, S Belforte, WH Bell, G Bellettini, J Bellinger, D Benjamin, J Bensinger, A Beretvas, JP Berge, J Berryhill, A Bhatti, M Binkley, D Bisello, M Bishai, RE Blair, C Blocker, K Bloom, B Blumenfeld, SR Blusk, A Bocci, A Bodek, G Bolla, Y Bonushkin, D Bortoletto, J Boudreau, A Brandl, S van den Brink, C Bromberg, M Brozovic, E Brubaker, N Bruner, E Buckley-Geer, J Budagov, HS Budd, K Burkett, G Busetto, A Byon-Wagner, KL Byrum, S Cabrera, P Calafiura, M Campbell, W Carithers, J Carlson, D Carlsmith, W Caskey, A Castro, D Cauz, A Cerri, J Chapman, C Chen, YC Chen, M Chertok, G Chiarelli, I Chirikov-Zorin, G Chlachidze, F Chlebana, L Christofek, YS Chung, AG Clark, AP Colijn, A Connolly, M Cordelli, J Cranshaw, R Cropp, D Dagenhart, S D'Auria, F DeJongh, S Dell'Agnello, M Dell'Orso, S Demers, L Demortier, M Deninno, PF Derwent, JR Dittmann

Abstract:

We present a detailed examination of the heavy flavor content of the W+jet data sample collected with the Collider Detector at Fermilab during the 1992-1995 collider run at the Fermilab Tevatron. Jets containing heavy flavor quarks are selected via the identification of secondary vertices or semileptonic decays of b and c quarks. There is generally good agreement between the rates of secondary vertices and soft leptons in the data and in the standard model simulation including single and pair production of top quarks. An exception is the number of events in which a single jet has both a soft lepton and a secondary vertex tag. In W+2,3 jet data, we find 13 such events where we expected 4.4±0.6 events. The kinematic properties of this small sample of events are statistically difficult to reconcile with the simulation of standard model processes.