721 research outputs found
Measurement of the Ratio sigma(t(t)over-bar)/sigma(Z/gamma*-> ll) and Precise Extraction of the t(t)over-bar Cross Section
No full textWe report a measurement of the ratio of the t (t) over bar to Z/gamma* production cross sections in root s = 1.96 TeV p (p) over bar collisions using data corresponding to an integrated luminosity of up to 4.6 fb(-1), collected by the CDF II detector. The t (t) over bar cross section ratio is measured using two complementary methods, a b-jet tagging measurement and a topological approach. By multiplying the ratios by the well-known theoretical Z/gamma* -> ll cross section predicted by the standard model, the extracted t (t) over bar cross sections are effectively insensitive to the uncertainty on luminosity. A best linear unbiased estimate is used to combine both measurements with the result sigma(t (t) over bar) = 7.70 +/- 0.52 pb, for a top-quark mass of 172.5 GeV/c(2)
Measurement of the Mass Difference between t and (t)over-bar Quarks
No full textWe present a direct measurement of the mass difference between t and (t) over bar quarks using t (t) over bar candidate events in the lepton + jets channel, collected with the CDF II detector at Fermilab's 1.96 TeV Tevatron p (p) over bar Collider. We make an event by event estimate of the mass difference to construct templates for top quark pair signal events and background events. The resulting mass difference distribution of data is compared to templates of signals and background using a maximum likelihood fit. From a sample corresponding to an integrated luminosity of 5.6 fb(-1), we measure a mass difference, Delta M-top = M-t - M-(t) over bar = - 3:3 +/- 1.4(stat) +/- 1.0(syst) GeV/c(2), approximately 2 standard deviations away from the CPT hypothesis of zero mass difference
Evidence for t(t)over-bar gamma production and measurement of sigma(t(t)over-bar gamma)/sigma(t(t)over-bar)
No full textUsing data corresponding to 6.0 fb(-1) of p (p) over bar collisions at root s = 1.96 TeV collected by the CDF II detector, we present a cross section measurement of top-quark pair production with an additional radiated photon in the central region with 10 GeV or more of transverse energy t (t) over bar gamma. The events are selected by looking for a lepton (l or mu), a photon (gamma), significant transverse momentum imbalance (is not an element of(T)), large total transverse energy, and three or more jets, with at least one identified as containing a b quark (b). Using an event selection optimized for the t (t) over bar gamma candidate sample, we also measure the cross section of t (t) over bar (sigma(t (t) over bar)). We measure the t (t) over bar gamma cross section (sigma(t (t) over bar gamma)) to be 0.18 +/- 0.08 pb, and the ratio of sigma(t (t) over bar gamma) to sigma(t (t) over bar) to be 0.024 +/- 0.009. We observe a probability of 0.0015 (3.0 standard deviations) of the background (non-t (t) over bar gamma events alone producing 30 events or more
Measurement of vector boson plus D? (2010)+ meson production in p-p collisions at s =1.96 TeV MEASUREMENT of VECTOR BOSON PLUS D? (2010)+ ... T. AALTONEN et al
No full textCitation: Aaltonen, T., Amerio, S., Amidei, D., Anastassov, A., Annovi, A., Antos, J., . . . Zucchelli, S. (2016). Measurement of vector boson plus D? (2010)+ meson production in p-p collisions at s =1.96 TeV MEASUREMENT of VECTOR BOSON PLUS D? (2010)+ ... T. AALTONEN et al. Physical Review D - Particles, Fields, Gravitation and Cosmology, 93(5). doi:10.1103/PhysRevD.93.052012Additional Authors: Aurisano, A.;Azfar, F.;Badgett, W.;Bae, T.;Barbaro-Galtieri, A.;Barnes, V. E.;Barnett, B. A.;Barria, P.;Bartos, P.;Bauce, M.;Bedeschi, F.;Behari, S.;Bellettini, G.;Bellinger, J.;Benjamin, D.;Beretvas, A.;Bhatti, A.;Bland, K. R.;Blumenfeld, B.;Bocci, A.;Bodek, A.;Bortoletto, D.;Boudreau, J.;Boveia, A.;Brigliadori, L.;Bromberg, C.;Brucken, E.;Budagov, J.;Budd, H. S.;Burkett, K.;Busetto, G.;Bussey, P.;Butti, P.;Buzatu, A.;Calamba, A.;Camarda, S.;Campanelli, M.;Canelli, F.;Carls, B.;Carlsmith, D.;Carosi, R.;Carrillo, S.;Casal, B.;Casarsa, M.;Castro, A.;Catastini, P.;Cauz, D.;Cavaliere, V.;Cerri, A.;Cerrito, L.;Chen, Y. C.;Chertok, M.;Chiarelli, G.;Chlachidze, G.;Cho, K.;Chokheli, D.;Clark, A.;Clarke, C.;Convery, M. E.;Conway, J.;Corbo, M.;Cordelli, M.;Cox, C. A.;Cox, D. J.;Cremonesi, M.;Cruz, D.;Cuevas, J.;Culbertson, R.;D'Ascenzo, N.;Datta, M.;De Barbaro, P.;Demortier, L.;Deninno, M.;D'Errico, M.;Devoto, F.;Di Canto, A.;Di Ruzza, B.;Dittmann, J. R.;Donati, S.;D'Onofrio, M.;Dorigo, M.;Driutti, A.;Ebina, K.;Edgar, R.;Elagin, A.;Erbacher, R.;Errede, S.;Esham, B.;Farrington, S.;Fernández Ramos, J. P.;Field, R.;Flanagan, G.;Forrest, R.;Franklin, M.;Freeman, J. C.;Frisch, H.;Funakoshi, Y.;Galloni, C.;Garfinkel, A. F.;Garosi, P.;Gerberich, H.;Gerchtein, E.;Giagu, S.;Giakoumopoulou, V.;Gibson, K.;Ginsburg, C. M.;Giokaris, N.;Giromini, P.;Glagolev, V.;Glenzinski, D.;Gold, M.;Goldin, D.;Golossanov, A.;Gomez, G.;Gomez-Ceballos, G.;Goncharov, M.;González López, O.;Gorelov, I.;Goshaw, A. T.;Goulianos, K.;Gramellini, E.;Grosso-Pilcher, C.;Group, R. C.;Guimaraes Da Costa, J.;Hahn, S. R.;Han, J. Y.;Happacher, F.;Hara, K.;Hare, M.;Harr, R. F.;Harrington-Taber, T.;Hatakeyama, K.;Hays, C.;Heinrich, J.;Herndon, M.;Hocker, A.;Hong, Z.;Hopkins, W.;Hou, S.;Hughes, R. E.;Husemann, U.;Hussein, M.;Huston, J.;Introzzi, G.;Iori, M.;Ivanov, A.;James, E.;Jang, D.;Jayatilaka, B.;Jeon, E. J.;Jindariani, S.;Jones, M.;Joo, K. K.;Jun, S. Y.;Junk, T. R.;Kambeitz, M.;Kamon, T.;Karchin, P. E.;Kasmi, A.;Kato, Y.;Ketchum, W.;Keung, J.;Kilminster, B.;Kim, D. H.;Kim, H. S.;Kim, J. E.;Kim, M. J.;Kim, S. H.;Kim, S. B.;Kim, Y. J.;Kim, Y. K.;Kimura, N.;Kirby, M.;Knoepfel, K.;Kondo, K.;Kong, D. J.;Konigsberg, J.;Kotwal, A. V.;Kreps, M.;Kroll, J.;Kruse, M.;Kuhr, T.;Kurata, M.;Laasanen, A. T.;Lammel, S.;Lancaster, M.;Lannon, K.;Latino, G.;Lee, H. S.;Lee, J. S.;Leo, S.;Leone, S.;Lewis, J. D.;Limosani, A.;Lipeles, E.;Lister, A.;Liu, H.;Liu, Q.;Liu, T.;Lockwitz, S.;Loginov, A.;Lucchesi, D.;Lucà, A.;Lueck, J.;Lujan, P.;Lukens, P.;Lungu, G.;Lys, J.;Lysak, R.;Madrak, R.;Maestro, P.;Malik, S.;Manca, G.;Manousakis-Katsikakis, A.;Marchese, L.;Margaroli, F.;Marino, P.;Matera, K.;Mattson, M. E.;Mazzacane, A.;Mazzanti, P.;McNulty, R.;Mehta, A.;Mehtala, P.;Mesropian, C.;Miao, T.;Mietlicki, D.;Mitra, A.;Miyake, H.;Moed, S.;Moggi, N.;Moon, C. S.;Moore, R.;Morello, M. J.;Mukherjee, A.;Muller, T.;Murat, P.;Mussini, M.;Nachtman, J.;Nagai, Y.;Naganoma, J.;Nakano, I.;Napier, A.;Nett, J.;Neu, C.;Nigmanov, T.;Nodulman, L.;Noh, S. Y.;Norniella, O.;Oakes, L.;Oh, S. H.;Oh, Y. D.;Oksuzian, I.;Okusawa, T.;Orava, R.;Ortolan, L.;Pagliarone, C.;Palencia, E.;Palni, P.;Papadimitriou, V.;Parker, W.;Pauletta, G.;Paulini, M.;Paus, C.;Phillips, T. J.;Piacentino, G.;Pianori, E.;Pilot, J.;Pitts, K.;Plager, C.;Pondrom, L.;Poprocki, S.;Potamianos, K.;Pranko, A.;Prokoshin, F.;Ptohos, F.;Punzi, G.;Redondo Fernández, I.;Renton, P.;Rescigno, M.;Rimondi, F.;Ristori, L.;Robson, A.;Rodriguez, T.;Rolli, S.;Ronzani, M.;Roser, R.;Rosner, J. L.;Ruffini, F.;Ruiz, A.;Russ, J.;Rusu, V.;Sakumoto, W. K.;Sakurai, Y.;Santi, L.;Sato, K.;Saveliev, V.;Savoy-Navarro, A.;Schlabach, P.;Schmidt, E. E.;Schwarz, T.;Scodellaro, L.;Scuri, F.;Seidel, S.;Seiya, Y.;Semenov, A.;Sforza, F.;Shalhout, S. Z.;Shears, T.;Shepard, P. F.;Shimojima, M.;Shochet, M.;Shreyber-Tecker, I.;Simonenko, A.;Sliwa, K.;Smith, J. R.;Snider, F. D.;Song, H.;Sorin, V.;Denis, R. S.;Stancari, M.;Stentz, D.;Strologas, J.;Sudo, Y.;Sukhanov, A.;Suslov, I.;Takemasa, K.;Takeuchi, Y.;Tang, J.;Tecchio, M.;Teng, P. K.;Thom, J.;Thomson, E.;Thukral, V.;Toback, D.;Tokar, S.;Tollefson, K.;Tomura, T.;Tonelli, D.;Torre, S.;Torretta, D.;Totaro, P.;Trovato, M.;Ukegawa, F.;Uozumi, S.;Vázquez, F.;Velev, G.;Vellidis, C.;Vernieri, C.;Vidal, M.;Vilar, R.;Vizán, J.;Vogel, M.;Volpi, G.;Wagner, P.;Wallny, R.;Wang, S. M.;Waters, D.;Wester, W. C., III;Whiteson, D.;Wicklund, A. B.;Wilbur, S.;Williams, H. H.;Wilson, J. S.;Wilson, P.;Winer, B. L.;Wittich, P.;Wolbers, S.;Wolfe, H.;Wright, T.;Wu, X.;Wu, Z.;Yamamoto, K.;Yamato, D.;Yang, T.;Yang, U. K.;Yang, Y. C.;Yao, W. M.;Yeh, G. P.;Yi, K.;Yoh, J.;Yorita, K.;Yoshida, T.;Yu, G. B.;Yu, I.;Zanetti, A. M.;Zeng, Y.;Zhou, C.;Zucchelli, S.A measurement of vector boson (V) production in conjunction with a D?(2010)+ meson is presented. Using a data sample corresponding to 9.7 fb-1 of proton-antiproton collisions at center-of-mass energy s=1.96 TeV produced by the Fermilab Tevatron, we reconstruct V+D?+ samples with the CDF II detector. The D?+ is fully reconstructed in the D?(2010)+?D0(?K-?+)?+ decay mode. This technique is sensitive to the associated production of vector boson plus charm or bottom mesons. We measure the ratio of production cross sections ?(W+D?)/?(W)=[1.75±0.13(stat)±0.09(stat)]% and ?(Z+D?)/?(Z)=[1.5±0.4(stat)±0.2(stat)]% and perform a differential measurement of d?(W+D?)/dpT(D?). Event properties are utilized to determine the fraction of V+D?(2010)+ events originating from different production processes. The results are in agreement with the predictions obtained with the pythia program, limiting possible contribution from non-standard-model physics processes. © 2016 American Physical Society
Measurement of R = B(t→Wb)/B(t→Wq) in top-quark-pair decays using lepton+jets events and the full CDF run II dataset
No full textWe present a measurement of the ratio of the top-quark branching fractions R=B(t→Wb)/ B(t→Wq), where q represents quarks of type b, s, or d, in the final state with a lepton and hadronic jets. The measurement uses √s=1.96 TeV proton-antiproton collision data from 8.7 fb[superscript -1] of integrated luminosity collected with the Collider Detector at Fermilab during Run II of the Tevatron. We simultaneously measure R=0.94±0.09 (stat+syst) and the tt̅ production cross section σ[subscript tt̅] =7.5±1.0 (stat+syst) pb. The magnitude of the Cabibbo-Kobayashi-Maskawa matrix element, |V[subscript tb]|=0.97±0.05 (stat+syst) is extracted assuming three generations of quarks, and a lower limit of |V[subscript tb]|>0.89 at 95% credibility level is set.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio
Search for New T′ Particles in Final States with Large Jet Multiplicities and Missing Transverse Energy in pp̅ Collisions at √s=1.96 TeV
No full textWe present a search for a new particle T′ decaying to a top quark via T′→t+X, where X goes undetected. We use a data sample corresponding to 5.7 fb[superscript -1] of integrated luminosity of pp̅ collisions with √s=1.96 TeV, collected at Fermilab Tevatron by the CDF II detector. Our search for pair production of T′ is focused on the hadronic decay channel, pp̅ →T′T̅ ′→tt̅ +XX̅ →bqq̅ b̅ qq̅ +XX̅ . We interpret our results in terms of a model where T′ is an exotic fourth generation quark and X is a dark matter particle. The data are consistent with standard model expectations. We set a limit on the generic production of T′T̅ ′→tt̅ +XX̅ , excluding the fourth generation exotic quarks T′ at 95% confidence level up to mT′=400 GeV/c[superscript 2] for mX≤70 GeV/c[superscript 2]
Measurement of the top-quark mass in the dilepton channel using the full CDF Run II data set
No full textWe present a measurement of the top-quark mass in events containing two leptons (electrons or muons) with a large transverse momentum, two or more energetic jets, and a transverse-momentum imbalance. We use the full proton-antiproton collision data set collected by the CDF experiment during the Fermilab Tevatron Run~II at center-of-mass energy TeV, corresponding to an integrated luminosity of . A special observable is exploited for an optimal reduction of the dominant systematic uncertainty, associated with the knowledge of the absolute energy of the hadronic jets. The distribution of this observable in the selected events is compared to simulated distributions of dilepton signal and background. We measure a value for the top-quark mass of GeV/
Measurement of the cross section for t(t)over-bar production in p(p)over-bar collisions using the kinematics of lepton plus jets events
No full textWe present a measurement of the top pair production cross section in p (p) over bar collisions at root s=1.96 TeV. We collect a data sample with an integrated luminosity of 194 +/- 11 pb(-1) with the CDF II detector at the Fermilab Tevatron. We use an artificial neural network technique to discriminate between top pair production and background processes in a sample of 519 lepton+jets events, which have one isolated energetic charged lepton, large missing transverse energy and at least three energetic jets. We measure the top pair production cross section to be sigma(t (t) over bar)=6.6 +/- 1.1 +/- 1.5 pb, where the first uncertainty is statistical and the second is systematic
Measurement of the Mass Difference between t and (t)over-bar Quarks
No full textWe present a direct measurement of the mass difference between t and (t) over bar quarks using t (t) over bar candidate events in the lepton + jets channel, collected with the CDF II detector at Fermilab’s 1.96 TeV Tevatron p (p) over bar Collider. We make an event by event estimate of the mass difference to construct templates for top quark pair signal events and background events. The resulting mass difference distribution of data is compared to templates of signals and background using a maximum likelihood fit. From a sample corresponding to an integrated luminosity of 5.6 fb(-1), we measure a mass difference, Delta M-top = M-t - M-(t) over bar = - 3:3 +/- 1.4(stat) +/- 1.0(syst) GeV/c(2), approximately 2 standard deviations away from the CPT hypothesis of zero mass difference
Measurement of B(t→Wb)/B(t→Wq) in Top-Quark-Pair Decays Using Dilepton Events and the Full CDF Run II Data Set
No full textWe present a measurement of the ratio of the top-quark branching fractions R=B(t→Wb)/B(t→Wq), where q represents any quark flavor, in events with two charged leptons, imbalance in total transverse energy, and at least two jets. The measurement uses proton-antiproton collision data at center-of-mass energy 1.96 TeV, corresponding to an integrated luminosity of 8.7 fb−1 collected with the Collider Detector at Fermilab during Run II of the Tevatron. We measure R to be 0.87±0.07, and extract the magnitude of the top-bottom quark coupling to be |Vtb|=0.93±0.04, assuming three generations of quarks. Under these assumptions, a lower limit of |Vtb|>0.85(0.87) at 95% (90%) credibility level is set
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