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G. Busetto

Università degli Studi di Padova, Dipartimento di Fisica e Astronomia G. Galilei, Faculty Member

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Papers by G. Busetto

The CDF silicon vertex detector

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1994

A silicon strip vertex detector "u designed, constmcted and comml.,ioned at the CDF Up-d h Tedron... more A silicon strip vertex detector "u designed, constmcted and comml.,ioned at the CDF Up-d h Tedron 4lida at F&b. The mt&rdcsI d&n of the detector, ita coolkq mud IIu+ni* ue pmalted. The ed end elutrania anployiq. Clllt0m VLSI chip, the readout electmnia and ntious componemta of the SVX ytom are daaibed. The s,.tem pafarnuncc aad the q&axe with ti opa&iaa of the detector in the radi.tim envixommnt dmcuued. The device bu been tu coIIi* beam data since May of 1999, pcrf.xmi,,s Eeitl bat design specilhtions and a&an+ the physica progxm of CDF. 'Operated by Ihe Univmitia Raearcb Au&don under cmtr~t with the US Department of Encw. 'Supported by the U. S. Dsputmcnt of En-.nd Lemmce Berkeley Laborazy under c~nw.ct No. DEACOS. 76SFC%'&3

Effective lifetime measurements in the Bs 0→K+K-, B0→K+π-and B0 s→π+K-decays

Physics Letters B, 2014

decays are presented using 1.0 fb −1 of pp collision data collected at a centre-of-mass energy of... more decays are presented using 1.0 fb −1 of pp collision data collected at a centre-of-mass energy of 7 TeV by the LHCb experiment. The analysis uses a data-driven approach to correct for the decay time acceptance. The measured effective lifetimes are τ B 0 s →K + K − = 1.407 ± 0.016 (stat) ± 0.007 (syst) ps, τ B 0 →K + π − = 1.524 ± 0.011 (stat) ± 0.004 (syst) ps, τ B 0 s →π + K − = 1.60 ± 0.06 (stat) ± 0.01 (syst) ps. This is the most precise determination to date of the effective lifetime in the B 0 s → K + K − decay and provides constraints on contributions from physics beyond the Standard Model to the B 0 s mixing phase and the width difference Γ s .

Measurement of CP asymmetry in D-0 -> K- K+ and D-0 -> pi(-) pi(+) decays

Journal of High Energy Physics, 2014

Time-integrated CP asymmetries in D 0 decays to the final states K − K + and π − π + are measured... more Time-integrated CP asymmetries in D 0 decays to the final states K − K + and π − π + are measured using proton-proton collisions corresponding to 3 fb −1 of integrated luminosity collected at centre-of-mass energies of 7 TeV and 8 TeV. The D 0 mesons are produced in semileptonic b-hadron decays, where the charge of the accompanying muon is used to determine the initial flavour of the charm meson. The difference in CP asymmetries between the two final states is measured to be ∆A CP = A CP (K − K +) − A CP (π − π +) = (+0.14 ± 0.16 (stat) ± 0.08 (syst))%. A measurement of A CP (K − K +) is obtained assuming negligible CP violation in charm mixing and in Cabibbo-favoured D decays. It is found to be A CP (K − K +) = (−0.06 ± 0.15 (stat) ± 0.10 (syst))% , where the correlation coefficient between ∆A CP and A CP (K − K +) is ρ = 0.28. By combining these results, the CP asymmetry in the D 0 → π − π + channel is A CP (π − π +) = (−0.20 ± 0.19 (stat) ± 0.10 (syst))%.

Measurement of the ratio B(ppWe)/B(ppZ0ee) in pp collisions at s =1800 GeV

Physical Review D, 1995

We present an analysis of data from p p¯ collisions at a center-of-mass energy of &surd;s =18... more We present an analysis of data from p p¯ collisions at a center-of-mass energy of &surd;s =1800 GeV. A measurement is made of the ratio R≡sigmaB(p p¯-->W-->enu)/sigmaB(p p¯-->Z0-->ee). The data represent 19.6 pg-1 collected by the Collider Detector at Fermilab during the 1992-1993 collider run of the Fermilab Tevatron. We find R=10.90+/-0.32(stat)+/-0.29(syst), and from this value we extract a measurement of the W-->enu branching ratio Gamma(W-->enu)/Gamma(W)=0.1094+/-0.0033(stat)+/-0.0031(syst). From this branching ratio we set a limit on the top quark mass of mt>62 GeV/c2 at the 95% confidence level. In contrast with direct searches for the top quark, this limit makes no assumptions about the allowed decay modes of the top quark. In addition, we use a calculation of the leptonic width Gamma(W-->enu) to obtain a value for the W total decay width: Gamma(W)=2.064+/-0.060(stat)+/-0.059(syst) GeV.

Study of J/psi production and cold nuclear matter effects in pPb collisions at root S-NN=5 TeV

Journal of High Energy Physics, 2014

ABSTRACT

Evidence for the decay B-c(+) -> J/psi 3 pi(+)2 pi(-)

Journal of High Energy Physics, 2014

Evidence is presented for the decay B + c → J/ψ 3π + 2π − using proton-proton collision data, cor... more Evidence is presented for the decay B + c → J/ψ 3π + 2π − using proton-proton collision data, corresponding to an integrated luminosity of 3 fb −1 , collected with the LHCb detector. A signal yield of 32 ± 8 decays is found with a significance of 4.5 standard deviations. The ratio of the branching fraction of the B + c → J/ψ 3π + 2π − decay to that of the B + c → J/ψ π + decay is measured to be B (B + c → J/ψ 3π + 2π −) B B + c → J/ψ π + = 1.74 ± 0.44 ± 0.24, where the first uncertainty is statistical and the second is systematic.

A study of CP violation in B-+/- -> DK +/- and B-+/- -> D pi(+/-) decays with D -> (KSK +/-)-K-0 pi(-/+) final states

Physics Letters B, 2014

A first study of CP violation in the decay modes B

Search for the rare decays B(+) -> mu(+)mu(-)K(+), B(0) -> mu(+)mu(-) K*(892)(0), and B(s)(0) -> mu(+)mu(-)phi at CDF

Physical Review D, 2009

Measurement of the top quark mass using the invariant mass of lepton pairs in soft muon b-tagged events

Physical Review D, 2009

Measurement of the b-hadron production cross section using decays to mu(-)D(0)X final states in p(p)over-bar collisions at root s=1.96 TeV

Physical Review D, 2009

We report a measurement of the production cross section for b hadrons in p " p collisions at ffif... more We report a measurement of the production cross section for b hadrons in p " p collisions at ffiffi ffi s p ¼ 1:96 TeV. Using a data sample derived from an integrated luminosity of 83 pb À1 collected with the upgraded Collider Detector (CDF II) at the Fermilab Tevatron, we analyze b hadrons, H b , partially reconstructed in the semileptonic decay mode H b ! À D 0 X. Our measurement of the inclusive production cross section for b hadrons with transverse momentum p T > 9 GeV=c and rapidity jyj < 0:6 is ¼ 1:30 b AE 0:05 bðstatÞ AE 0:14 bðsystÞ AE 0:07 bðBÞ, where the uncertainties are statistical, systematic, and from branching fractions, respectively. The differential cross sections d=dp T are found to be in good agreement with recent measurements of the H b cross section and well described by fixed-order next-to-leading logarithm predictions.

Study of substructure of high transverse momentum jets produced in proton-antiproton collisions at root s=1.96 TeV

Physical Review D, 2012

Measurement of form-factor-independent observables in the decay B0→K(*0)μ(+)μ(-)

Physical review letters, Jan 8, 2013

We present a measurement of form-factor-independent angular observables in the decay B(0)→K*(892)... more We present a measurement of form-factor-independent angular observables in the decay B(0)→K*(892)(0)μ(+)μ(-). The analysis is based on a data sample corresponding to an integrated luminosity of 1.0 fb(-1), collected by the LHCb experiment in pp collisions at a center-of-mass energy of 7 TeV. Four observables are measured in six bins of the dimuon invariant mass squared q² in the range 0.1<q²<19.0 GeV²/c(4). Agreement with recent theoretical predictions of the standard model is found for 23 of the 24 measurements. A local discrepancy, corresponding to 3.7 Gaussian standard deviations is observed in one q² bin for one of the observables. Considering the 24 measurements as independent, the probability to observe such a discrepancy, or larger, in one is 0.5%.

Observation of the Resonant Character of theZ(4430)−State

Physical Review Letters, 2014

Search of glueballs in the decay

Physics Letters B, 1986

In a study of the radmtlve decay J/q~ ~ ~'~4~ ~ "yK+K-K+K-, from the 8 6 mllhon Jfik produced m t... more In a study of the radmtlve decay J/q~ ~ ~'~4~ ~ "yK+K-K+K-, from the 8 6 mllhon Jfik produced m the DM2 experiment at DCI, we found a large production of events with 4~q~ mass below the ~c The branching ratm, for m4~4~ < 2 9 GeV/c 2 , is BR(J/¢ ~ 3"~) = (3 1 ± 0 3 ± 0 6) X 10-4 The angular analysis of the events with q~¢ mass below 2 fGeV/c 2 is consistent with a 2 ~ assignment An enhancement near 2 2 GeV/c 2 shows a preferred spin-parity YP = 0

Events with large missing transverse energy at the CERN collider: III. Mass limits on supersymmetric particles

Physics Letters B, 1987

Beauty production at the CERN proton-antiproton collider

Physics Letters B, 1987

Measurement of the top quark mass in the all-hadronic mode at CDF

Physics Letters B, 2012

A measurement of the top quark mass (Mtop) in the all-hadronic decay channel is presented. It use... more A measurement of the top quark mass (Mtop) in the all-hadronic decay channel is presented. It uses 5.8 fb −1 of pp data collected with the CDF II detector at the Fermilab Tevatron Collider. Events with six to eight jets are selected by a neural network algorithm and by the requirement that at least one of the jets is tagged as a b quark jet. The measurement is performed with a likelihood fit technique, which simultaneously determines Mtop and the jet energy scale (JES) calibration. The fit yields a value of Mtop = 172.5 ± 1.4 (stat) ± 1.0 (JES) ± 1.1 (syst) GeV/c 2 .

Measurement of the Difference inCP-Violating Asymmetries inD0→K+K−andD0→π+π−Decays at CDF

Physical Review Letters, 2012

We report a measurement of the difference (∆ACP) between time-integrated CP-violating asymmetries... more We report a measurement of the difference (∆ACP) between time-integrated CP-violating asymmetries in D 0 → K + K − and D 0 → π + π − decays reconstructed in the full data set of protonantiproton collisions collected by the Collider Detector at Fermilab, corresponding to 9.7 fb −1 of integrated luminosity. The strong decay D * + → D 0 π + is used to identify the charm meson at production as D 0 or D 0. We measure ∆ACP = −0.62 ± 0.21 (stat) ± 0.10 (syst) %, which differs from zero by 2.7 Gaussian standard deviations. This result supports similar evidence for CP violation in charm-quark decays obtained in proton-proton collisions.

Search for New Dielectron Resonances and Randall-Sundrum Gravitons at the Collider Detector at Fermilab

Physical Review Letters, 2011

A search for new dielectron mass resonances using data recorded by the CDF II detector and corres... more A search for new dielectron mass resonances using data recorded by the CDF II detector and corresponding to an integrated luminosity of 5.7 fb −1 is presented. No significant excess over the expected standard model prediction is observed. In this dataset, an event with the highest dielectron mass ever observed (960 GeV/c 2) was recorded. The results are interpreted in the Randall-Sundrum (RS) model. Combined with the 5.4 fb −1 diphoton analysis, the RS-graviton lower mass limit for the coupling k/M P l = 0.1 is 1058 GeV/c 2 , making it the strongest limit to date.

Search for a Heavy Toplike Quark inpp¯Collisions ats=1.96 TeV

Physical Review Letters, 2011

We present the results of a search for pair production of a heavy top-like (t) quark decaying to ... more We present the results of a search for pair production of a heavy top-like (t) quark decaying to W q final states using data corresponding to an integrated luminosity of 5.6 fb −1 collected by the CDF II detector in pp collisions at √ s = 1.96 TeV. We perform parallel searches for t → W b and t → W q (where q is a generic down-type quark) in events containing a lepton and four or more jets. By performing a fit to the two-dimensional distribution of total transverse energy versus reconstructed t quark mass, we set upper limits on the t t production cross section and exclude a standard model fourth-generation t quark decaying to W b (W q) with mass below 358 (340) GeV/c 2 at 95% CL.

The CDF silicon vertex detector

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1994

A silicon strip vertex detector "u designed, constmcted and comml.,ioned at the CDF Up-d h Tedron... more A silicon strip vertex detector "u designed, constmcted and comml.,ioned at the CDF Up-d h Tedron 4lida at F&b. The mt&rdcsI d&n of the detector, ita coolkq mud IIu+ni* ue pmalted. The ed end elutrania anployiq. Clllt0m VLSI chip, the readout electmnia and ntious componemta of the SVX ytom are daaibed. The s,.tem pafarnuncc aad the q&axe with ti opa&iaa of the detector in the radi.tim envixommnt dmcuued. The device bu been tu coIIi* beam data since May of 1999, pcrf.xmi,,s Eeitl bat design specilhtions and a&an+ the physica progxm of CDF. 'Operated by Ihe Univmitia Raearcb Au&don under cmtr~t with the US Department of Encw. 'Supported by the U. S. Dsputmcnt of En-.nd Lemmce Berkeley Laborazy under c~nw.ct No. DEACOS. 76SFC%'&3

Effective lifetime measurements in the Bs 0→K+K-, B0→K+π-and B0 s→π+K-decays

Physics Letters B, 2014

decays are presented using 1.0 fb −1 of pp collision data collected at a centre-of-mass energy of... more decays are presented using 1.0 fb −1 of pp collision data collected at a centre-of-mass energy of 7 TeV by the LHCb experiment. The analysis uses a data-driven approach to correct for the decay time acceptance. The measured effective lifetimes are τ B 0 s →K + K − = 1.407 ± 0.016 (stat) ± 0.007 (syst) ps, τ B 0 →K + π − = 1.524 ± 0.011 (stat) ± 0.004 (syst) ps, τ B 0 s →π + K − = 1.60 ± 0.06 (stat) ± 0.01 (syst) ps. This is the most precise determination to date of the effective lifetime in the B 0 s → K + K − decay and provides constraints on contributions from physics beyond the Standard Model to the B 0 s mixing phase and the width difference Γ s .

Measurement of CP asymmetry in D-0 -> K- K+ and D-0 -> pi(-) pi(+) decays

Journal of High Energy Physics, 2014

Time-integrated CP asymmetries in D 0 decays to the final states K − K + and π − π + are measured... more Time-integrated CP asymmetries in D 0 decays to the final states K − K + and π − π + are measured using proton-proton collisions corresponding to 3 fb −1 of integrated luminosity collected at centre-of-mass energies of 7 TeV and 8 TeV. The D 0 mesons are produced in semileptonic b-hadron decays, where the charge of the accompanying muon is used to determine the initial flavour of the charm meson. The difference in CP asymmetries between the two final states is measured to be ∆A CP = A CP (K − K +) − A CP (π − π +) = (+0.14 ± 0.16 (stat) ± 0.08 (syst))%. A measurement of A CP (K − K +) is obtained assuming negligible CP violation in charm mixing and in Cabibbo-favoured D decays. It is found to be A CP (K − K +) = (−0.06 ± 0.15 (stat) ± 0.10 (syst))% , where the correlation coefficient between ∆A CP and A CP (K − K +) is ρ = 0.28. By combining these results, the CP asymmetry in the D 0 → π − π + channel is A CP (π − π +) = (−0.20 ± 0.19 (stat) ± 0.10 (syst))%.

Measurement of the ratio B(ppWe)/B(ppZ0ee) in pp collisions at s =1800 GeV

Physical Review D, 1995

We present an analysis of data from p p¯ collisions at a center-of-mass energy of &surd;s =18... more We present an analysis of data from p p¯ collisions at a center-of-mass energy of &surd;s =1800 GeV. A measurement is made of the ratio R≡sigmaB(p p¯-->W-->enu)/sigmaB(p p¯-->Z0-->ee). The data represent 19.6 pg-1 collected by the Collider Detector at Fermilab during the 1992-1993 collider run of the Fermilab Tevatron. We find R=10.90+/-0.32(stat)+/-0.29(syst), and from this value we extract a measurement of the W-->enu branching ratio Gamma(W-->enu)/Gamma(W)=0.1094+/-0.0033(stat)+/-0.0031(syst). From this branching ratio we set a limit on the top quark mass of mt>62 GeV/c2 at the 95% confidence level. In contrast with direct searches for the top quark, this limit makes no assumptions about the allowed decay modes of the top quark. In addition, we use a calculation of the leptonic width Gamma(W-->enu) to obtain a value for the W total decay width: Gamma(W)=2.064+/-0.060(stat)+/-0.059(syst) GeV.

Study of J/psi production and cold nuclear matter effects in pPb collisions at root S-NN=5 TeV

Journal of High Energy Physics, 2014

ABSTRACT

Evidence for the decay B-c(+) -> J/psi 3 pi(+)2 pi(-)

Journal of High Energy Physics, 2014

Evidence is presented for the decay B + c → J/ψ 3π + 2π − using proton-proton collision data, cor... more Evidence is presented for the decay B + c → J/ψ 3π + 2π − using proton-proton collision data, corresponding to an integrated luminosity of 3 fb −1 , collected with the LHCb detector. A signal yield of 32 ± 8 decays is found with a significance of 4.5 standard deviations. The ratio of the branching fraction of the B + c → J/ψ 3π + 2π − decay to that of the B + c → J/ψ π + decay is measured to be B (B + c → J/ψ 3π + 2π −) B B + c → J/ψ π + = 1.74 ± 0.44 ± 0.24, where the first uncertainty is statistical and the second is systematic.

A study of CP violation in B-+/- -> DK +/- and B-+/- -> D pi(+/-) decays with D -> (KSK +/-)-K-0 pi(-/+) final states

Physics Letters B, 2014

A first study of CP violation in the decay modes B

Search for the rare decays B(+) -> mu(+)mu(-)K(+), B(0) -> mu(+)mu(-) K*(892)(0), and B(s)(0) -> mu(+)mu(-)phi at CDF

Physical Review D, 2009

Measurement of the top quark mass using the invariant mass of lepton pairs in soft muon b-tagged events

Physical Review D, 2009

Measurement of the b-hadron production cross section using decays to mu(-)D(0)X final states in p(p)over-bar collisions at root s=1.96 TeV

Physical Review D, 2009

We report a measurement of the production cross section for b hadrons in p " p collisions at ffif... more We report a measurement of the production cross section for b hadrons in p " p collisions at ffiffi ffi s p ¼ 1:96 TeV. Using a data sample derived from an integrated luminosity of 83 pb À1 collected with the upgraded Collider Detector (CDF II) at the Fermilab Tevatron, we analyze b hadrons, H b , partially reconstructed in the semileptonic decay mode H b ! À D 0 X. Our measurement of the inclusive production cross section for b hadrons with transverse momentum p T > 9 GeV=c and rapidity jyj < 0:6 is ¼ 1:30 b AE 0:05 bðstatÞ AE 0:14 bðsystÞ AE 0:07 bðBÞ, where the uncertainties are statistical, systematic, and from branching fractions, respectively. The differential cross sections d=dp T are found to be in good agreement with recent measurements of the H b cross section and well described by fixed-order next-to-leading logarithm predictions.

Study of substructure of high transverse momentum jets produced in proton-antiproton collisions at root s=1.96 TeV

Physical Review D, 2012

Measurement of form-factor-independent observables in the decay B0→K(*0)μ(+)μ(-)

Physical review letters, Jan 8, 2013

We present a measurement of form-factor-independent angular observables in the decay B(0)→K*(892)... more We present a measurement of form-factor-independent angular observables in the decay B(0)→K*(892)(0)μ(+)μ(-). The analysis is based on a data sample corresponding to an integrated luminosity of 1.0 fb(-1), collected by the LHCb experiment in pp collisions at a center-of-mass energy of 7 TeV. Four observables are measured in six bins of the dimuon invariant mass squared q² in the range 0.1<q²<19.0 GeV²/c(4). Agreement with recent theoretical predictions of the standard model is found for 23 of the 24 measurements. A local discrepancy, corresponding to 3.7 Gaussian standard deviations is observed in one q² bin for one of the observables. Considering the 24 measurements as independent, the probability to observe such a discrepancy, or larger, in one is 0.5%.

Observation of the Resonant Character of theZ(4430)−State

Physical Review Letters, 2014

Search of glueballs in the decay

Physics Letters B, 1986

In a study of the radmtlve decay J/q~ ~ ~'~4~ ~ "yK+K-K+K-, from the 8 6 mllhon Jfik produced m t... more In a study of the radmtlve decay J/q~ ~ ~'~4~ ~ "yK+K-K+K-, from the 8 6 mllhon Jfik produced m the DM2 experiment at DCI, we found a large production of events with 4~q~ mass below the ~c The branching ratm, for m4~4~ < 2 9 GeV/c 2 , is BR(J/¢ ~ 3"~) = (3 1 ± 0 3 ± 0 6) X 10-4 The angular analysis of the events with q~¢ mass below 2 fGeV/c 2 is consistent with a 2 ~ assignment An enhancement near 2 2 GeV/c 2 shows a preferred spin-parity YP = 0

Events with large missing transverse energy at the CERN collider: III. Mass limits on supersymmetric particles

Physics Letters B, 1987

Beauty production at the CERN proton-antiproton collider

Physics Letters B, 1987

Measurement of the top quark mass in the all-hadronic mode at CDF

Physics Letters B, 2012

A measurement of the top quark mass (Mtop) in the all-hadronic decay channel is presented. It use... more A measurement of the top quark mass (Mtop) in the all-hadronic decay channel is presented. It uses 5.8 fb −1 of pp data collected with the CDF II detector at the Fermilab Tevatron Collider. Events with six to eight jets are selected by a neural network algorithm and by the requirement that at least one of the jets is tagged as a b quark jet. The measurement is performed with a likelihood fit technique, which simultaneously determines Mtop and the jet energy scale (JES) calibration. The fit yields a value of Mtop = 172.5 ± 1.4 (stat) ± 1.0 (JES) ± 1.1 (syst) GeV/c 2 .

Measurement of the Difference inCP-Violating Asymmetries inD0→K+K−andD0→π+π−Decays at CDF

Physical Review Letters, 2012

We report a measurement of the difference (∆ACP) between time-integrated CP-violating asymmetries... more We report a measurement of the difference (∆ACP) between time-integrated CP-violating asymmetries in D 0 → K + K − and D 0 → π + π − decays reconstructed in the full data set of protonantiproton collisions collected by the Collider Detector at Fermilab, corresponding to 9.7 fb −1 of integrated luminosity. The strong decay D * + → D 0 π + is used to identify the charm meson at production as D 0 or D 0. We measure ∆ACP = −0.62 ± 0.21 (stat) ± 0.10 (syst) %, which differs from zero by 2.7 Gaussian standard deviations. This result supports similar evidence for CP violation in charm-quark decays obtained in proton-proton collisions.

Search for New Dielectron Resonances and Randall-Sundrum Gravitons at the Collider Detector at Fermilab

Physical Review Letters, 2011

A search for new dielectron mass resonances using data recorded by the CDF II detector and corres... more A search for new dielectron mass resonances using data recorded by the CDF II detector and corresponding to an integrated luminosity of 5.7 fb −1 is presented. No significant excess over the expected standard model prediction is observed. In this dataset, an event with the highest dielectron mass ever observed (960 GeV/c 2) was recorded. The results are interpreted in the Randall-Sundrum (RS) model. Combined with the 5.4 fb −1 diphoton analysis, the RS-graviton lower mass limit for the coupling k/M P l = 0.1 is 1058 GeV/c 2 , making it the strongest limit to date.

Search for a Heavy Toplike Quark inpp¯Collisions ats=1.96 TeV

Physical Review Letters, 2011

We present the results of a search for pair production of a heavy top-like (t) quark decaying to ... more We present the results of a search for pair production of a heavy top-like (t) quark decaying to W q final states using data corresponding to an integrated luminosity of 5.6 fb −1 collected by the CDF II detector in pp collisions at √ s = 1.96 TeV. We perform parallel searches for t → W b and t → W q (where q is a generic down-type quark) in events containing a lepton and four or more jets. By performing a fit to the two-dimensional distribution of total transverse energy versus reconstructed t quark mass, we set upper limits on the t t production cross section and exclude a standard model fourth-generation t quark decaying to W b (W q) with mass below 358 (340) GeV/c 2 at 95% CL.