We present a measurement of the W boson mass in W-->e(nu) decays using 1 fb-1 of data collected with the D0 detector during Run II of the Fermilab Tevatron collider. With a sample of 499830 W-->e(nu) candidate events, we measure M(W)=80.401+/-0.043 GeV. This is the most precise measurement from a single experiment.

Measurement of the B -Meson Lifetime S. R. Wagner, ' D. A. Hinshaw, ' R. A. Ong, A. Snyder, G. Abrams, " C. E. Adolphsen, C. Akerlof, J. P. Alexander, ( M. Alvarez, ' D. Amidei, A. R. Baden, J. Ballam, B. C. Barish, T. Barklow, B. A. Barnett, ) J. Bartelt, ) D. Blockus, G. Bonvicini, A. Boyarski, J. Boyer, B. Brabson, ) A. Breakstone, ( ) J. M. Brom, ) F. Bulos, ( P. R. Burchat, D. L. Burke, F. Butler, ) F. Calvino, ') R. J. Cence, ( ) J. Chapman, ) D. Cords, ( D. P. Coupal, H. C. DeStaebler, ( ) D. E. Dorfan, J. M. Dorfan, ( ) P. S. Drell, G. J. Feldman, E. Fernandez, ' R. C. Field, W. T. Ford, ' C. Fordham (2) R. Frey'(6) D. Fujino (2) K. K. Gan, (2) G. Gidal, (4) L. Gladney (2) T. Glanzman, (2) M. S. Gold, G. Goldhaber, A. Green, ) P. Grosse-Wiesmann, ( ) J. Haggerty, G. Hanson, ) R. Harr, ( ) F. A. Harris, ( ) C. M. Hawkes, ( K. Hayes, D. Herrup, C. A. Heusch, T. Himel, ( ) R. J. Hollebeek, ( ) D. Hutchinson, (2) J. Hylen, (s) W. R. Innes, (2) M. Jaffre, ( ) J. A. Jaros, I. Juricic, ( ) J. A. Kadyk, D. Karlen, J. Kent, S. R. Klein, W. Koska, W. Kozanecki, A. J. Lankford, R. R. Larsen, (2) B W. Leclalre(2) 'M E. Levi, (4) A. M. Litke, (5) N. S. L~kyer, (2) V. Luth (2)'J A J Matthews, D. I. Meyer, B. D. Milliken, K. C. Moffeit, L. Miiller, J. Nash, M. E. Nelson, D. Nitz, ( ) H. Ogren, ( K. F. O'Shaughnessy, ( S. I. Parker, ( ) C. Peck, ( M. L. Perl, A. Petersen, M. Petradza, F. C. Porter, P. Rankin, ' B. Richter, K. Riles, P. C. Rowson, D. R. Rust, H. F. W. Sadrozinski, (5) T. Schaad, (' ) T. L. Schalk, ( ) H. Schellman, ( ) W. B. Schmidke, (4) A. S. Schwarz, ( A. Seiden, ( ) P. D. Sheldon, ( ) J. G. Smith, ') E. Soderstrom, D. P. Stoker, ( ) R. Stroynowski, R. Thun, G. H. Trilling, " R. Tschirhart, R. Van Kooten, H. Veltman, P. Voruganti, ) P. Weber, ' A. J. Weinstein, S. Weisz, ( S. L. White, ' E. Wicklund, A. J. Weir, D. R. Wood, D. Y. Wu, and J. M. Yelton ")University of Colorado, Boulder, Colorado 80309 ' 'Stanford Linear Accelerator Center, Stanford University, Stanford, California 94309 ' Indiana University, Bloomington, Indiana 47405 ' 'Lawrence Berkeley Laboratory and Department of Physics, University of California, Berkeley, California 94720 (~'University of California, Santa Cruz, California 95064 (6)University of Michigan, Ann Arbor, Michigan 48109 ("California Institute of Technology, Pasadena, California 91125 Johns Hopkins University, Baltimore, Maryland 2)218 ( )University of Hawaii, Honolulu, Hawaii 96822 Harvard University, Cambridge, Massachusetts 02138 (Received 20 November 1989)

Over 2000 photomultiplier tubes have been selected as the readout device of the upgrade CDF Endplug calorimeter, a scintillator tile sampling calorimeter with wave-shifter fiber readout. The specifications were set on various properties of the tubes for the electromagnetic and hadronic compartments and a series of rigorous tests were made on 2216 Hamamatsu R4125, 10-stage 19mm diameter tubes with green-extended bialkali photocathode. On all of the test items, the distributions of the data were well clustered with minor tails, and the original specifications based on a small ensemble were well suited for rejecting the tails of the distributions. After rejecting 5.4% of the total, 960 tubes for electromagnetic and 864 tubes for hadronic compartments were allocated to projective towers based on their linear dynamic ranges. Tubes with greater linear ranges were assigned to larger pseudo-rapidity channels where greater single-tower energy deposits were expected. This paper describes how we selected the phototubes for our calorimeter and presents the results of the study we made.

We present the first measurement of associated direct photon + muon production in hadronic collisions, from a sample of 1.8 TeV pp collisions recorded with the Collider Detector at Fermilab.Quantum chromodynamics (QCD) predicts that these events are primarily from the Compton scattering process cg → cγ, with the final state charm quark producing a muon.Hence this measurement is sensitive to the charm quark content of the proton.The measured cross section of 29±9 pb is compared to a leadingorder QCD parton shower model as well as a next-to-leading-order QCD calculation.

We present the first measurement of the jet pseudorapidity distribution in direct photon events from a sample of p{bar p} collisions at {radical} (s) =1.8TeV, recorded with the Collider Detector at Fermilab. Quantum chromodynamics (QCD) predicts that these events are primarily from hard quark-gluon Compton scattering, qg{r_arrow}q{gamma}, with the final state quark producing the jet of hadrons. The jet pseudorapidity distribution in this model is sensitive to parton momentum fractions between 0.015 and 0.15. We find that the shape of the measured pseudorapidity distribution agrees well with next-to-leading order QCD calculations. {copyright} {ital 1997} {ital The American Physical Society}

The Collider Detector at Fermilab is upgrading its end plug calorimeter from a gas detector system to one using scintillating tiles read out through wavelength shifting fibers. This upgrade is required to take advantage of the increase in luminosity which the Tevatron will provide in the future. The tile-fiber calorimeter, which is longitudinally segmented into electromagnetic and hadronic sections, will be read out through 1824 photomultiplier tubes. The performance requirements of the calorimeter demand that the PMTs have good response to light in the 500nm region, provide adequate amplification for signals from minimum ionizing particles, provide linear response for peak anode currents up to 25mA at a gain of 5×104, and fit into the restricted space at the rear of the plugs. For convenience, we also desire a single PMT and base combination be used for the electromagnetic and hadron calorimeters even though the required gains in these sections differ by a factor of 10. This paper describes the evaluation process used to determine the adequacy of the commercially available PMTs which appeared to meet our performance requirements.

We present the first general measurements (invariant-mass, transverse-energy, and angular distributions) of the process, ¯p→pγ+2 jets+X, using data collected by the CDF at Fermilab. We compare the data with predictions from a tree-level QCD calculation and the PYTHIA shower Monte Carlo program. Our data sample is particularly sensitive to contributions from initial- and final-state radiation of photons and jets. Using the PYTHIA Monte Carlo program, we contrast the kinematical distributions for direct photon production with those for initial- and final-state photon radiation (bremsstrahlung). Based on the angular distributions, we find that our data favor a mixture of bremsstrahlung and direct photon production, as predicted, over either process alone.Received 24 April 1997DOI:https://doi.org/10.1103/PhysRevD.57.67©1998 American Physical Society

Jet pseudorapidity distribution in direct photon events in pp̄ collisions at As51.8 TeV F. Abe, M. G. Albrow, S. R. Amendolia, 22 D. Amidei, J. Antos, 28 C. Anway-Wiese, 4 G. Apollinari, H. Areti, M. Atac, P. Auchincloss, 25 F. Azfar, P. Azzi, N. Bacchetta, 20 W. Badgett, 16 M. W. Bailey, J. Bao, 35 P. de Barbaro, 25 A. Barbaro-Galtieri, 14 V. E. Barnes, 24 B. A. Barnett, 12 P. Bartalini, 22 G. Bauer, 15 T. Baumann, 9 F. Bedeschi, 22 S. Behrends, 3 S. Belforte, 22 G. Bellettini, J. Bellinger, 34 D. Benjamin, 31 J. Benlloch, 15 J. Bensinger, 3 D. Benton, 21 A. Beretvas, 7 J. P. Berge, 7 S. Bertolucci, 8 A. Bhatti, K. Biery, M. Binkley, F. Bird, D. Bisello, R. E. Blair, C. Blocker, 3 A. Bodek, W. Bokhari, V. Bolognesi, 22 D. Bortoletto, 24 C. Boswell, 12 T. Boulos, 14 G. Brandenburg, 9 C. Bromberg, 17 E. Buckley-Geer, 7 H. S. Budd, 25 K. Burkett, G. Busetto, 20 A. Byon-Wagner, 7 K. L. Byrum, J. Cammerata, 12 C. Campagnari, 7 M. Campbell, 16 A. Caner, 7 W. Carithers, 14 D. Carlsmith, 34 A. Castro, 20 Y. Cen, F. Cervelli, H. Y. Chao, 28 J. Chapman, 16 M.-T. Cheng, 28 G. Chiarelli, T. Chikamatsu, 32 C. N. Chiou, 28 L. Christofek, 10 S. Cihangir, 7 A. G. Clark, M. Cobal, M. Contreras, 5 J. Conway, 27 J. Cooper, 7 M. Cordelli, C. Couyoumtzelis, 22 D. Crane, 1 J. D. Cunningham, 3 T. Daniels, 15 F. DeJongh, 7 S. Delchamps, 7 S. Dell’Agnello, M. Dell’Orso, L. Demortier, 26 B. Denby, 22 M. Deninno, 2 P. F. Derwent, 16 T. Devlin, M. Dickson, J. R. Dittmann, 6 S. Donati, 22 R. B. Drucker, 14 A. Dunn, K. Einsweiler, 14 J. E. Elias, 7 R. Ely, E. Engels, Jr., 23 S. Eno, 5 D. Errede, 10 S. Errede, 10 Q. Fan, 25 B. Farhat, 15 I. Fiori, B. Flaugher, 7 G. W. Foster, 7 M. Franklin, M. Frautschi, 18 J. Freeman, 7 J. Friedman, 15 H. Frisch, 5 A. Fry, T. A. Fuess, 1 Y. Fukui, S. Funaki, 32 G. Gagliardi, 22 S. Galeotti, 22 M. Gallinaro, A. F. Garfinkel, 24 S. Geer, 7 D. W. Gerdes, 16 P. Giannetti, 22 N. Giokaris, 26 P. Giromini, L. Gladney, 21 D. Glenzinski, 12 M. Gold, J. Gonzalez, 21 A. Gordon, 9 A. T. Goshaw, 6 K. Goulianos, 26 H. Grassmann, 6 A. Grewal, L. Groer, C. Grosso-Pilcher, 5 C. Haber, 14 S. R. Hahn, 7 R. Hamilton, 9 R. Handler, 34 R. M. Hans, 35 K. Hara, B. Harral, R. M. Harris, S. A. Hauger, 6 J. Hauser, 4 C. Hawk, J. Heinrich, 21 D. Cronin-Hennessy, 6 R. Hollebeek, 21 L. Holloway, A. Hölscher, 11 S. Hong, 16 G. Houk, P. Hu, B. T. Huffman, R. Hughes, 25 P. Hurst, 9 J. Huston, 17 J. Huth, 9 J. Hylen, 7 M. Incagli, J. Incandela, 7 H. Iso, H. Jensen, 7 C. P. Jessop, 9 U. Joshi, 7 R. W. Kadel, 14 E. Kajfasz, 7,* T. Kamon, 30 T. Kaneko, 32 D. A. Kardelis, H. Kasha, 35 Y. Kato, L. Keeble, 8 R. D. Kennedy, 27 R. Kephart, 7 P. Kesten, 14 D. Kestenbaum, 9 R. M. Keup, H. Keutelian, 7 F. Keyvan, 4 D. H. Kim, H. S. Kim, S. B. Kim, S. H. Kim, Y. K. Kim, L. Kirsch, P. Koehn, 25 K. Kondo, J. Konigsberg, 9 S. Kopp, 5 K. Kordas, 11 W. Koska, 7 E. Kovacs, 7,* W. Kowald, M. Krasberg, 16 J. Kroll, M. Kruse, S. E. Kuhlmann, 1 E. Kuns, 27 A. T. Laasanen, 24 N. Labanca, 22 S. Lammel, 4 J. I. Lamoureux, 3 T. LeCompte, 10 S. Leone, 22 J. D. Lewis, 7 P. Limon, M. Lindgren, T. M. Liss, N. Lockyer, C. Loomis, 27 O. Long, M. Loreti, E. H. Low, J. Lu, D. Lucchesi, 22 C. B. Luchini, P. Lukens, 7 J. Lys, P. Maas, 34 K. Maeshima, 7 A. Maghakian, 26 P. Maksimovic, 15 M. Mangano, 22 J. Mansour, 17 M. Mariotti, J. P. Marriner, 7 A. Martin, J. A. J. Matthews, 18 R. Mattingly, P. McIntyre, 30 P. Melese, 26 A. Menzione, 22 E. Meschi, 22 G. Michail, S. Mikamo, 13 M. Miller, 5 R. Miller, T. Mimashi, S. Miscetti, 8 M. Mishina, H. Mitsushio, 32 S. Miyashita, 32 Y. Morita, S. Moulding, 26 J. Mueller, 27 A. Mukherjee, 7 T. Muller, P. Musgrave, 11 L. F. Nakae, 29 I. Nakano, 32 C. Nelson, 7 D. Neuberger, 4 C. Newman-Holmes, 7 L. Nodulman, 1 S. Ogawa, 32 S. H. Oh, 6 K. E. Ohl, R. Oishi, T. Okusawa, 19 C. Pagliarone, 22 R. Paoletti, 22 V. Papadimitriou, 31 S. P. Pappas, 35 S. Park, 7 J. Patrick, 7 G. Pauletta, 22 M. Paulini, L. Pescara, 20 M. D. Peters, 14 T. J. Phillips, 6 G. Piacentino, 2 M. Pillai, R. Plunkett, 7 L. Pondrom, 34 N. Produit, 14 J. Proudfoot, 1 F. Ptohos, 9 G. Punzi, 22 K. Ragan, 11 F. Rimondi, L. Ristori, M. Roach-Bellino, 33 W. J. Robertson, 6 T. Rodrigo, 7 J. Romano, 5 L. Rosenson, 15 W. K. Sakumoto, 25 D. Saltzberg, 5 A. Sansoni, 8 V. Scarpine, 30 A. Schindler, 14 P. Schlabach, 9 E. E. Schmidt, 7 M. P. Schmidt, 35 O. Schneider, 14 G. F. Sciacca, 22 A. Scribano, 22 S. Segler, 7 S. Seidel, 18 Y. Seiya, 32 G. Sganos, 11 A. Sgolacchia, 2 M. Shapiro, 14 N. M. Shaw, 24 Q. Shen, 24 P. F. Shepard, 23 M. Shimojima, M. Shochet, 5 J. Siegrist, 29 A. Sill, P. Sinervo, 11 P. Singh, 23 J. Skarha, 12 K. Sliwa, D. A. Smith, F. D. Snider, 12 L. Song, 7 T. Song, 16 J. Spalding, 7 L. Spiegel, 7 P. Sphicas, 15 L. Stanco, 20 J. Steele, 34 A. Stefanini, 22 K. Strahl, J. Strait, 7 D. Stuart, 7 G. Sullivan, 5 K. Sumorok, 15 R. L. Swartz, Jr., 10 T. Takahashi, 19 K. Takikawa, 32 F. Tartarelli, 22 W. Taylor, P. K. Teng, 28 Y. Teramoto, 19 S. Tether, 15 D. Theriot, J. Thomas, 29 T. L. Thomas, 18 R. Thun, 16 M. Timko, P. Tipton, 25 A. Titov, S. Tkaczyk, 7 K. Tollefson, A. Tollestrup, 7 J. Tonnison, 24 J. F. de Troconiz, 9 J. Tseng, 12 M. Turcotte, 29 N. Turini, N. Uemura, 32 F. Ukegawa, 21 G. Unal, S. C. van den Brink, 23 S. Vejcik III, R. Vidal, M. Vondracek, 10 D. Vucinic, R. G. Wagner, 1 R. L. Wagner, 7 N. Wainer, 7 R. C. Walker, 25 C. Wang, 6 C. H. Wang, 28 G. Wang, 22 J. Wang, 5 M. J. Wang, 28 Q. F. Wang, 26 A. Warburton, 11 G. Watts, 25 T. Watts, R. Webb, 30 C. Wei, C. Wendt, 34 H. Wenzel, 14 W. C. Wester III, 7 T. Westhusing, 10 A. B. Wicklund, E. Wicklund, R. Wilkinson, H. H. Williams, P. Wilson, B. L. Winer, J. Wolinski, D. Y. Wu, X. Wu, J. Wyss, 20 A. Yagil, W. Yao, K. Yasuoka, 32 Y. Ye, G. P. Yeh, 7 P. Yeh, 28 M. Yin, J. Yoh, C. Yosef, 17 T. Yoshida, 19 D. Yovanovitch, 7 I. Yu, J. C. Yun, 7 A. Zanetti, F. Zetti, L. Zhang, 34 S. Zhang, 16 W. Zhang, 21 and S. Zucchelli 2

We report a new measurement of dijet production by color-singlet exchange in p (p) over bar collisions at root s = 1.8 TeV at the Fermilab Tevatron. In a sample of events with two jets of transverse energy E-T(jet) > 20 GeV, pseudorapidity in the range 1.8 < \eta(jet)\ < 3.5, and eta(1) eta(2) < 0, we find that a fraction R = [1.13 +/- 0.12(stat) +/- 0.11(syst)]% has a pseudorapidity gap within \eta\ < 1 between the jets that can be attributed to color-singlet exchnage. The fraction R shows no significant dependence on E-T(jet) or on the pseudorapidity separation between the jets. [S0031-9007(97)05184-3].

We present the first general measurements (invariant-mass, transverse-energy, and angular distributions) of the process, (p) over bar p-->gamma+2 jets + X, using data collected by the CDF at Fermilab. We compare the data with predictions from a tree-level QCD calculation and the PYTHIA shower Monte Carlo program. Our data sample is particularly sensitive to contributions from initial-and final-state radiation of photons and jets. Using the PYTHIA Monte Carlo program, we contrast the kinematical distributions for direct photon production with those for initial-and final-state photon radiation (bremsstrahlung). Based on the angular distributions, we find that our data favor a mixture of bremsstrahlung and direct photon production, as predicted, over either process alone. [S0556-2821(97)01623-8].

We present the first measurement of the jet pseudorapidity distribution in direct photon events from a sample of pp¯ collisions at s=1.8TeV, recorded with the Collider Detector at Fermilab. Quantum chromodynamics (QCD) predicts that these events are primarily from hard quark-gluon Compton scattering, qg→qγ, with the final state quark producing the jet of hadrons. The jet pseudorapidity distribution in this model is sensitive to parton momentum fractions between 0.015 and 0.15. We find that the shape of the measured pseudorapidity distribution agrees well with next-to-leading order QCD calculations.Received 14 August 1997DOI:https://doi.org/10.1103/PhysRevD.57.1359©1998 American Physical Society

We present evidence for dilepton events from t tbar production with one electron or muon and one hadronically decaying tau lepton from the decay t tbar -> (l nu_l) (tau nu_tau) b bbar, (l=e, mu), using the Collider Detector at Fermilab (CDF). In a 109 pb^-1 data sample of p pbar collisions at sqrt(s) = 1.8 TeV we expect ~1 signal event and a total background of ~2 events; we observe 4 candidate events (2 e tau and 2 mu tau). Three of these events have jets identified as b candidates, compared to an estimated background of 0.28+-0.02 events.

We have measured the fraction of J/psi mesons originating from chi(c) meson decays in p (p) over bar collisions at root s = 1.8 TeV. The fraction, for P-T/(J/psi) > 4.0 GeV/c and \(eta) over dot(J/psi) < 0.6, not including contributions from b flavored hadrons, is 29.7% +/- 1.7%(stat) +/- 5.7%(syst). We have determined the cross sections for J/psi mesons originating from chi(c) decays and for directly produced J/psi mesons. We have found that direct J/psi production is in excess of the prediction of the color singlet model by the same factor found for direct psi(2S) production.

We describe the properties of six-jet events, with the six-jet mass exceeding 520 GeV/c(2), produced at the Fermilab proton-antiproton collider operating at a center-of-mass energy of 1.8 TeV. Observed distributions for a set of 20 multijet variables are compared with predictions from the HERWIG QCD parton shower Monte Carlo program, the NJETS leading order QCD matrix element Monte Carlo program, and a phase-space model in which six-jet events are distributed uniformly over the kinematically allowed region of the six-body phase space. In general the QCD predictions provide a good description of the observed six-jet distributions.

We present measurements of correlated b¯b cross sections, μ−μ correlations, the average B0¯B0 mixing parameter ¯χ, and a limit on the CP-violating parameter εB. For these measurements, we use muon pairs from b¯b double semileptonic decays. The data used in this analysis were taken with the Collider Detector at Fermilab and represent an integrated luminosity of 17.4±0.6 pb−1. The results concerning b¯b production correlations are compared to predictions of next-to-leading order QCD computations.Received 12 August 1996DOI:https://doi.org/10.1103/PhysRevD.55.2546©1997 American Physical Society

We report the observation and measurement of the rate of diffractive dijet production at the Fermilab Tevatron (p) over bar p collider at root s = 1.8 TeV. In events with two jets of E-T > 20 GeV, 1.8 < \eta\ < 3.5, and eta(1) eta(2) > 0, we find that the diffractive to nondiffractive production ratio is R-JJ = [0.75 +/- 0.05(stat) +/- 0.09(syst)]%. By comparing this result, in combination with our measured rate for diffractive W boson production reported previously, with predictions based on a hard partonic pomeron structure, we determine the pomeron gluon fraction to be f(g) = 0.7 +/- 0.2.