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daniela bortoletto
University of Oxford, Physics, Faculty Member
Research Interests:
We report the first evidence of charmless semileptonic decays of B mesons. In the momentum interval 2.4–2.6 GeV/c where the background from b→clν is negligible, the average of the measured b→ueν and b→uμν partial ...
Research Interests:
Abstract: We present a measurement of the cross section and the first measurement of the heavy flavor content of associated direct photon+ muon events produced in hadronic collisions. These measurements come from a sample of 1.8 TeV ppbar... more
Abstract: We present a measurement of the cross section and the first measurement of the heavy flavor content of associated direct photon+ muon events produced in hadronic collisions. These measurements come from a sample of 1.8 TeV ppbar collisions recorded with the Collider Detector at Fermilab. Quantum chromodynamics (QCD) predicts that these events are primarily due to Compton scattering process charm+ gluon-> charm+ photon, with the final state charm quark producing a muon.
The production of W bosons in association with jets in pp collisions at the Fermilab Tevatron Collider provides the opportunity to test many standard model SM 1 predictions. Previous Collider Detector at Fermilab CDF measurements 2 of the... more
The production of W bosons in association with jets in pp collisions at the Fermilab Tevatron Collider provides the opportunity to test many standard model SM 1 predictions. Previous Collider Detector at Fermilab CDF measurements 2 of the inclusive W cross section and of the yield of W jet events as a function of the jet multiplicity and transverse momentum show agreement between data and the electroweak and QCD predictions of the standard model.
A search for neutral minimal supersymmetric standard model (MSSM) Higgs bosons in pp collisions at the LHC at a center-of-mass energy of 7 TeV is presented. The results are based on a data sample corresponding to an integrated luminosity... more
A search for neutral minimal supersymmetric standard model (MSSM) Higgs bosons in pp collisions at the LHC at a center-of-mass energy of 7 TeV is presented. The results are based on a data sample corresponding to an integrated luminosity of 36 pb Ā1 recorded by the CMS experiment. The search uses decays of the Higgs bosons to tau pairs. No excess is observed in the tau-pair invariant-mass spectrum.
At the Fermilab Tevatron, top quarks produced in pairs through the strong interaction were observed 1, 2. Within the standard model, top quarks are also expected to be produced singly in the electroweak channel 3, mainly through off mass... more
At the Fermilab Tevatron, top quarks produced in pairs through the strong interaction were observed 1, 2. Within the standard model, top quarks are also expected to be produced singly in the electroweak channel 3, mainly through off mass shell W production ''W*''and W-gluon fusion ''Wg''processes, shown in Fig. 1.
We present the first measurement of the ratio of branching fractions RB (t! Wb)/B (t! Wq) from pp collisions at ps 1.8 TeV. The data set corresponds to 109 pb21 of data recorded by the Collider Detector at Fermilab during the 1992–95... more
We present the first measurement of the ratio of branching fractions RB (t! Wb)/B (t! Wq) from pp collisions at ps 1.8 TeV. The data set corresponds to 109 pb21 of data recorded by the Collider Detector at Fermilab during the 1992–95 Tevatron run. We measure R 0.9410. 31 20.24 (stat 1 syst) or R. 0.61 (0.56) at 90%(95)% CL, in agreement with the standard model predictions. This measurement yields a limit on the Cabibbo-Kobayashi-Maskawa quark mixing matrix element jVtbj under the assumption of three generations and unitarity.
A. Abulencia,23 D. Acosta,17 J. Adelman,13 T. Affolder,10 T. Akimoto,54 MG Albrow,16 D. Ambrose,16 S. Amerio,42 D. Amidei,33 A. Anastassov,51 K. Anikeev,16 A. Annovi,45 J. Antos,1 M. Aoki,54 G. Apollinari,16 J.-F. Arguin,32 T. Arisawa,56... more
A. Abulencia,23 D. Acosta,17 J. Adelman,13 T. Affolder,10 T. Akimoto,54 MG Albrow,16 D. Ambrose,16 S. Amerio,42 D. Amidei,33 A. Anastassov,51 K. Anikeev,16 A. Annovi,45 J. Antos,1 M. Aoki,54 G. Apollinari,16 J.-F. Arguin,32 T. Arisawa,56 A. Artikov,14 W. Ashmanskas,16 A. Attal,8 F. Azfar,41 P. Azzi-Bacchetta,42 P. Azzurri,45 N. Bacchetta,42 H. Bachacou,28 W. Badgett,16 A. Barbaro-Galtieri,28 VE Barnes,47 BA Barnett,24 S. Baroiant,7 V. Bartsch,30 G. Bauer,31 F. Bedeschi,45 S. Behari,24 S. Belforte,53 G.
7 TeV, with a data sample corresponding to an integrated luminosity of 1: 14 fb Ą1, collected by the CMS experiment at the LHC. In both cases, the number of events observed after all selection requirements is consistent with expectations... more
7 TeV, with a data sample corresponding to an integrated luminosity of 1: 14 fb Ą1, collected by the CMS experiment at the LHC. In both cases, the number of events observed after all selection requirements is consistent with expectations from background and standard-model signal predictions. The resulting upper limits on the branching fractions are BšB0 s! ž ĄŽ< 1: 9 Ā 10Ą8 and BšB0! ž ĄŽ< 4: 6 Ā 10Ą9, at 95% confidence level.
We report a measurement of the strong coupling constant, as (MZ), extracted from inclusive jet production in pp collisions at ps 1800 GeV. The QCD prediction for the evolution of as with jet transverse energy ET is tested over the range... more
We report a measurement of the strong coupling constant, as (MZ), extracted from inclusive jet production in pp collisions at ps 1800 GeV. The QCD prediction for the evolution of as with jet transverse energy ET is tested over the range 40, ET, 450 GeV using ET for the renormalization scale. The data show good agreement with QCD in the region below 250 GeV. The value of as at the mass of the Z0 boson averaged over the range 40, ET, 250 GeV is found to be as (MZ) 0.1178 6 0.0001 (stat) 10.0081 20.0095 (expt. syst).
We present a search for standard model (SM) Higgs boson production using p" p collision data at ffiffiffi sp ¼ 1: 96 TeV, collected with the CDF II detector and corresponding to an integrated luminosity of 4: 8 fbÀ1. We search for Higgs... more
We present a search for standard model (SM) Higgs boson production using p" p collision data at ffiffiffi sp ¼ 1: 96 TeV, collected with the CDF II detector and corresponding to an integrated luminosity of 4: 8 fbÀ1. We search for Higgs bosons produced in all processes with a significant production rate and decaying to two W bosons.
Abstract A search is performed for an excess of events, over the standard model expectations, with a photon, a lepton, and large missing transverse energy in pp collisions at TeV. Such events are expected in many new physics models, in... more
Abstract A search is performed for an excess of events, over the standard model expectations, with a photon, a lepton, and large missing transverse energy in pp collisions at TeV. Such events are expected in many new physics models, in particular a supersymmetric theory that is broken via a gauge-mediated mechanism, when the lightest charged and neutral gauginos are mass degenerate. The data sample used in this search corresponds to an integrated luminosity of 35 pb-1 collected with the CMS detector at the LHC.
Measurements of the bottom quark production cross section at the Tevatron collider probe the ability of perturbative QCD to predict absolute rates in hadronic collisions. At the perturbative level, calculations of the hard scattering... more
Measurements of the bottom quark production cross section at the Tevatron collider probe the ability of perturbative QCD to predict absolute rates in hadronic collisions. At the perturbative level, calculations of the hard scattering cross sections have been carried out at next-to-leading order (NLO)[1] and also implemented with logarithmic pb
We report the first observation of the baryonic flavor-changing neutral current decay à 0 b! à þ À with 24 signal events and a statistical significance of 5.8 Gaussian standard deviations. This measurement uses ap" p collisions data... more
We report the first observation of the baryonic flavor-changing neutral current decay à 0 b! à þ À with 24 signal events and a statistical significance of 5.8 Gaussian standard deviations. This measurement uses ap" p collisions data sample corresponding to 6: 8 fb À1 at ffiffiffi sp ¼ 1: 96 TeV collected by the CDF II detector at the Tevatron collider. The total and differential branching ratios for à 0 b! à þ À are measured. We find Bðà 0 b! à þ ÀÞ¼½1: 73 Æ 0: 42ðstatÞÆðsystÞ Â 10À6.
Dijet production in PbPb collisions at a nucleon–nucleon center-of-mass energy of 2.76 TeV is studied with the CMS detector at the LHC. A data sample corresponding to an integrated luminosity of 150 μb− 1 is analyzed. Jets are... more
Dijet production in PbPb collisions at a nucleon–nucleon center-of-mass energy of 2.76 TeV is studied with the CMS detector at the LHC. A data sample corresponding to an integrated luminosity of 150 μb− 1 is analyzed. Jets are reconstructed using combined information from tracking and calorimetry, using the anti-kT algorithm with R= 0.3. The dijet momentum balance and angular correlations are studied as a function of collision centrality and leading jet transverse momentum.
A search for the standard model Higgs boson decaying to W+ W− in pp collisions at s= 7 TeV is reported. The data are collected at the LHC with the CMS detector, and correspond to an integrated luminosity of 4.6 fb− 1. The W+ W− candidates... more
A search for the standard model Higgs boson decaying to W+ W− in pp collisions at s= 7 TeV is reported. The data are collected at the LHC with the CMS detector, and correspond to an integrated luminosity of 4.6 fb− 1. The W+ W− candidates are selected in events with two charged leptons and large missing transverse energy. No significant excess of events above the standard model background expectations is observed, and upper limits on the Higgs boson production relative to the standard model Higgs expectation are derived.
We present searches for quark-lepton compositeness and a heavy W0 boson at high electron-neutrino transverse mass. We use 110 pb21 of data collected in pp collisions at ps 1.8 TeV by the CDF Collaboration during 1992–1995. The data are... more
We present searches for quark-lepton compositeness and a heavy W0 boson at high electron-neutrino transverse mass. We use 110 pb21 of data collected in pp collisions at ps 1.8 TeV by the CDF Collaboration during 1992–1995. The data are consistent with standard model expectations. Limits are set on the quark-lepton compositeness scale L, the ratio of partial cross sections s (W0! en)/s (W! en), and the mass of a W0 boson with standard model couplings.
We measure the masses of b hadrons in exclusively reconstructed final states containing a J=! ÿ decay using 220 pbÿ1 of data collected by the CDF II experiment. We find: m B 5279: 10 0: 41 stat: 0: 36 sys: MeV= c2, m B0 5279: 63 0: 53... more
We measure the masses of b hadrons in exclusively reconstructed final states containing a J=! ÿ decay using 220 pbÿ1 of data collected by the CDF II experiment. We find: m B 5279: 10 0: 41 stat: 0: 36 sys: MeV= c2, m B0 5279: 63 0: 53 stat: 0: 33 sys: MeV= c2, m B0 s 5366: 01 0: 73 stat: 0: 33 sys: MeV= c2, m 0 b 5619: 7 1: 2 stat: 1: 2 sys: MeV= c2. m B ÿ m B0 ÿ0: 53 0: 67 stat: 0: 14 sys: MeV= c2, m B0 s ÿ m B0 86: 38 0: 90 stat: 0: 06 sys: MeV= c2, m 0 b ÿ m B0 339: 2 1: 4 stat: 0: 1 sys: MeV= c2.
Abstract Measurements of primary charged hadron multiplicity distributions are presented for non-single-diffractive events in proton-proton collisions at centre-of-mass energies of, 2.36, and 7 TeV, in five pseudorapidity ranges from| η|<... more
Abstract Measurements of primary charged hadron multiplicity distributions are presented for non-single-diffractive events in proton-proton collisions at centre-of-mass energies of, 2.36, and 7 TeV, in five pseudorapidity ranges from| η|< 0. 5 to| η|< 2. 4. The data were collected with the minimum-bias trigger of the CMS experiment during the LHC commissioning runs in 2009 and the 7 TeV run in 2010. The multiplicity distribution at is in agreement with previous measurements.
We report the results of a search for second and third generation leptoquarks using 88 pb21 of data recorded by the Collider Detector at Fermilab. Color triplet technipions, which play the role of scalar leptoquarks, are investigated due... more
We report the results of a search for second and third generation leptoquarks using 88 pb21 of data recorded by the Collider Detector at Fermilab. Color triplet technipions, which play the role of scalar leptoquarks, are investigated due to their potential production in decays of strongly coupled color octet technirhos. Events with a signature of two heavy flavor jets and missing energy may indicate the decay of a second (third) generation leptoquark to a charm (bottom) quark and a neutrino.
We describe a search for anomalous production of events with two leptons (e or) of the same electric charge in pp collisions at a center-of-mass energy of 1.96 TeV. Many extensions to the standard model predict the production of two... more
We describe a search for anomalous production of events with two leptons (e or) of the same electric charge in pp collisions at a center-of-mass energy of 1.96 TeV. Many extensions to the standard model predict the production of two leptons of the same electric charge. This search has a significant increase in sensitivity compared to earlier searches.
We report a search for the flavor-changing neutral-current decay of the top quark t! Zq (q ¼ u, c) in p" p collisions at ffiffiffi sp ¼ 1: 96 TeV using a data sample corresponding to an integrated luminosity of 1: 9 fb À1 collected by the... more
We report a search for the flavor-changing neutral-current decay of the top quark t! Zq (q ¼ u, c) in p" p collisions at ffiffiffi sp ¼ 1: 96 TeV using a data sample corresponding to an integrated luminosity of 1: 9 fb À1 collected by the CDF II detector. This decay is strongly suppressed in the standard model and an observation of a signal at the Fermilab Tevatron would be an indication of physics beyond the standard model. Using Zþ!
The top quark is pair-produced in pp collisions through quark-antiquark annihilation and gluon-gluon fusion. The measurement of the tt cross section tests the QCD calculations for the pair production of a massive colored triplet. These... more
The top quark is pair-produced in pp collisions through quark-antiquark annihilation and gluon-gluon fusion. The measurement of the tt cross section tests the QCD calculations for the pair production of a massive colored triplet. These calculations have been performed in perturbation theory to next-to-leading-order [1, 2].
The standard model predictions for W and Z production are tested using an integrated luminosity of 200 pbÿ1 of pp collision data collected at the Collider Detector at Fermilab. The cross sections are measured by selecting leptonic decays... more
The standard model predictions for W and Z production are tested using an integrated luminosity of 200 pbÿ1 of pp collision data collected at the Collider Detector at Fermilab. The cross sections are measured by selecting leptonic decays of the W and Z bosons, and photons with transverse energy ET> 7 GeV that are well separated from leptons. The production cross sections and kinematic distributions for the W and Z data are compared to SM predictions.
D ç! D0 ç (and charge conjugate) decays with the D0 decaying to K ç, K Kç, and ç, corresponding to 123 pb 1 of data collected by the Collider Detector at Fermilab II experiment at the Fermilab Tevatron collider. No significant direct CP... more
D ç! D0 ç (and charge conjugate) decays with the D0 decaying to K ç, K Kç, and ç, corresponding to 123 pb 1 of data collected by the Collider Detector at Fermilab II experiment at the Fermilab Tevatron collider. No significant direct CP violation is observed. We measure ůD0! K Kçć= ůD0! K çć ł 0: 0992 0: 0011 0: 0012, ůD0! çć= ůD0! K çć ł 0: 035 94 0: 000 54 0: 000 40, ACPůK Kçćłů2: 0 1: 2 0: 6ć%, and ACPů çćłů1: 0 1: 3 0: 6ć%, where, in all cases, the first uncertainty is statistical and the second is systematic.
The transverse energy (E [subscript T]) in Pb-Pb collisions at 2.76 TeV nucleon-nucleon center-of-mass energy (√ sNN) has been measured over a broad range of pseudorapidity (η) and collision centrality by using the CMS detector at the... more
The transverse energy (E [subscript T]) in Pb-Pb collisions at 2.76 TeV nucleon-nucleon center-of-mass energy (√ sNN) has been measured over a broad range of pseudorapidity (η) and collision centrality by using the CMS detector at the LHC. The transverse energy density per unit pseudorapidity (dE [subscript T]/dη) increases faster with collision energy than the charged particle multiplicity. This implies that the mean energy per particle is increasing with collision energy.
We report on a search for the supersymmetric partner of the top quark top squark produced in tt events using 110 pb 1 of pp collisions at s 1.8 TeV recorded with the Collider Detector at Fermilab. In the case of a light top squark, the... more
We report on a search for the supersymmetric partner of the top quark top squark produced in tt events using 110 pb 1 of pp collisions at s 1.8 TeV recorded with the Collider Detector at Fermilab. In the case of a light top squark, the decay of the top quark into a top squark plus the lightest supersymmetric particle LSP could have a significant branching ratio. The observed events are consistent with standard model tt production and decay.
Abstract The results of searches for new physics in events with two same-sign isolated leptons, hadronic jets, and missing transverse energy in the final state are presented. The searches use an integrated luminosity of 35 pb− 1 of pp... more
Abstract The results of searches for new physics in events with two same-sign isolated leptons, hadronic jets, and missing transverse energy in the final state are presented. The searches use an integrated luminosity of 35 pb− 1 of pp collision data at a centre-of-mass energy of 7 TeV collected by the CMS experiment at the LHC. The observed numbers of events agree with the standard model predictions, and no evidence for new physics is found.
The top quark is the most massive known elementary particle. Its mass, mt, is 173: 3 Æ 1: 1 GeV= c2 [1], about 40 times larger than that of the bottom quark, the second-most massive standard model (SM) fermion. The top quark's large mass,... more
The top quark is the most massive known elementary particle. Its mass, mt, is 173: 3 Æ 1: 1 GeV= c2 [1], about 40 times larger than that of the bottom quark, the second-most massive standard model (SM) fermion. The top quark's large mass, at the scale of electroweak symmetry breaking, hints that it may play a role in the mechanism of mass generation.
Dÿ… s†‡‡ ÿ. We present the first measurement of the ratio of branching fractions Έ… B0 s! Dÿ s‡‡ ÿ†= Έ… B0! Dÿ‡‡ ÿ† ˆ 1: 05 0: 10… stat† 0: 22… syst†. We also update our measurement of Έ… B0 s! Dÿ s‡†= Έ… B0! Dÿ‡† to 1: 13 0: 08… stat† 0:... more
Dÿ… s†‡‡ ÿ. We present the first measurement of the ratio of branching fractions Έ… B0 s! Dÿ s‡‡ ÿ†= Έ… B0! Dÿ‡‡ ÿ† ˆ 1: 05 0: 10… stat† 0: 22… syst†. We also update our measurement of Έ… B0 s! Dÿ s‡†= Έ… B0! Dÿ‡† to 1: 13 0: 08… stat† 0: 23… syst†, improving the statistical uncertainty by more than a factor of 2. We find Έ… B0 s! Dÿ s‡† ˆ‰ 3: 8 0: 3… stat† 1: 3… syst† Š 10ÿ3 and Έ… B0 s! Dÿ s‡‡ ÿ† ˆ‰ 8: 4 0: 8… stat† 3: 2… syst† Š 10ÿ3.
Collaborations using significantly more data [2–6]. In this paper we present a new measurement of the top quark mass with greatly improved precision, using our entire data sample from the 1992–1995 runs, which corresponds to a total... more
Collaborations using significantly more data [2–6]. In this paper we present a new measurement of the top quark mass with greatly improved precision, using our entire data sample from the 1992–1995 runs, which corresponds to a total integrated luminosity of 109 6 7 pb21 [7]. This new measurement supersedes the results reported in [1, 2]. Within the standard model, the top quark decays more than 99% of the time into Wb. The W boson can then decay to a quark-antiquark or lepton-neutrino pair.
DI-fusion, le Dépôt institutionnel numérique de l'ULB, est l'outil de référencementde la production scientifique de l'ULB.L'interface de recherche DI-fusion permet de consulter les publications des chercheurs de l'ULB et les thèses qui y... more
DI-fusion, le Dépôt institutionnel numérique de l'ULB, est l'outil de référencementde la production scientifique de l'ULB.L'interface de recherche DI-fusion permet de consulter les publications des chercheurs de l'ULB et les thèses qui y ont été défendues.
Cross sections for heavy quark production in hard scattering interactions have been studied at p" p colliders at center-of-mass energies from 630 GeV [1] to 1.96 TeV [2–4] and in p-nucleus collisions with beam energies from 800 to 920 GeV... more
Cross sections for heavy quark production in hard scattering interactions have been studied at p" p colliders at center-of-mass energies from 630 GeV [1] to 1.96 TeV [2–4] and in p-nucleus collisions with beam energies from 800 to 920 GeV [5]. The expected cross sections can be calculated in perturbative quantum chromodynamics. The comparison between data and predictions provides a critical test of next-to-leading order (NLO) calculations [6].
Rapid Communications are intended for important new results which deserve accelerated publication, and are therefore given priority in the editorial office and in production. A Rapid Communication in Physical Review D should be no longer... more
Rapid Communications are intended for important new results which deserve accelerated publication, and are therefore given priority in the editorial office and in production. A Rapid Communication in Physical Review D should be no longer than five printed pages and must be accompanied by an abstract. Page proofs are sent to authors, but because of the accelerated schedule, publication is generally not delayed for receipt of corrections unless requested by the author.
A search for events with jets and missing transverse energy is performed in a data sample of pp collisions collected at ffiffiffi sp ¼ 7 TeV by the CMS experiment at the LHC. The analyzed data sample corresponds to an integrated... more
A search for events with jets and missing transverse energy is performed in a data sample of pp collisions collected at ffiffiffi sp ¼ 7 TeV by the CMS experiment at the LHC. The analyzed data sample corresponds to an integrated luminosity of 1: 14 fb À1. In this search, a kinematic variable T is used as the main discriminator between events with genuine and misreconstructed missing transverse energy. No excess of events over the standard model expectation is found.
We report on a search for the pair production of scalar leptoquarks (LQ), using 191 pbÿ1 of protonantiproton collision data recorded by the CDF experiment during Run II of the Tevatron. The leptoquarks are sought via their decay into a... more
We report on a search for the pair production of scalar leptoquarks (LQ), using 191 pbÿ1 of protonantiproton collision data recorded by the CDF experiment during Run II of the Tevatron. The leptoquarks are sought via their decay into a neutrino and quark yielding missing transverse energy and several jets of large transverse energy. No evidence for LQ production is observed, and limits are set on pp! LQLQX! q qX.
We present the first model independent search for three-jet hadronic resonances within multijet events in ffiffiffi sp ¼ 1: 96 TeV p" p collisions at the Fermilab Tevatron using the CDF II detector. Pair production of supersymmetric... more
We present the first model independent search for three-jet hadronic resonances within multijet events in ffiffiffi sp ¼ 1: 96 TeV p" p collisions at the Fermilab Tevatron using the CDF II detector. Pair production of supersymmetric gluinos and squarks with hadronic R-parity violating decays is employed as an example of a new physics benchmark for this signature. Selection criteria based on the kinematic properties of an ensemble of jet combinations within each event help to extract signal from copious QCD background.
The top quark, the weak isospin partner of the bottom quark, was first observed by the CDF and D0 collaborations in pp collisions produced at the Fermilab Tevatron [1]. During Run I operation from 1992 to 1995, CDF acquired 109 pbÿ1 of... more
The top quark, the weak isospin partner of the bottom quark, was first observed by the CDF and D0 collaborations in pp collisions produced at the Fermilab Tevatron [1]. During Run I operation from 1992 to 1995, CDF acquired 109 pbÿ1 of data at a center-of-mass energy of 1.8 TeV, and performed the first measurements of top quark properties. Since the start of Run II at the Tevatron in 2001, CDF has collected integrated luminosities several times that of Run I.
In the standard model of electroweak interactions 1, the quark mass eigenstates are related to the weak eigenstates via the unitary 33 Cabibbo-Kobayashi-Maskawa CKM matrix VCKM 2. The nine elements in this matrix, Vij, where iu, c, t and... more
In the standard model of electroweak interactions 1, the quark mass eigenstates are related to the weak eigenstates via the unitary 33 Cabibbo-Kobayashi-Maskawa CKM matrix VCKM 2. The nine elements in this matrix, Vij, where iu, c, t and jd, s, b, are completely determined from three angles and a phase. A nonzero phase gives CP violation in the weak interaction.
At the Fermilab Tevatron, where p" p collisions are produced at ffiffiffi sp ¼ 1: 96 TeV, Wþ (Wà) bosons are created primarily by the interaction of u (d) quarks from the proton and" d (" u) quarks from the antiproton. Since u quarks... more
At the Fermilab Tevatron, where p" p collisions are produced at ffiffiffi sp ¼ 1: 96 TeV, Wþ (Wà) bosons are created primarily by the interaction of u (d) quarks from the proton and" d (" u) quarks from the antiproton. Since u quarks carry, on average, a higher fraction of the proton's momentum than d quarks [1, 2], the W þ tends to be boosted along the proton beam direction, and the Wà tends to be boosted along the antiproton direction. The difference between the W þ and Wà rapidity distributions results in a charge asymmetry
We report on a search for narrow-width particles decaying to a top and antitop quark pair. The data set used in the analysis corresponds to an integrated luminosity of 680 pbÿ1 collected with the Collider Detector at Fermilab in run II.... more
We report on a search for narrow-width particles decaying to a top and antitop quark pair. The data set used in the analysis corresponds to an integrated luminosity of 680 pbÿ1 collected with the Collider Detector at Fermilab in run II. We present 95% confidence level upper limits on the cross section times branching ratio. Assuming a specific top-color-assisted technicolor production model, the leptophobic Z0 with width ÿZ0 0: 012MZ0, we exclude the mass range MZ0< 725 GeV= c2 at the 95% confidence level.
The bound states of bottom quarks provide a laboratory in which we can investigate the behavior of the strong force quantum chromodynamics or QCD and the electroweak interaction 1. The lowest-lying bound states are the pseudoscalar mesons... more
The bound states of bottom quarks provide a laboratory in which we can investigate the behavior of the strong force quantum chromodynamics or QCD and the electroweak interaction 1. The lowest-lying bound states are the pseudoscalar mesons B, B0, and B s 0 formed by one bottom antiquark bound to one of the three lightest quarks u, d, and s, respectively.
The integrated and differential cross sections for the production of pairs of isolated photons is measured in proton-proton collisions at a centre-of-mass energy of 7 TeV with the CMS detector at the LHC. A data sample corresponding to an... more
The integrated and differential cross sections for the production of pairs of isolated photons is measured in proton-proton collisions at a centre-of-mass energy of 7 TeV with the CMS detector at the LHC. A data sample corresponding to an integrated luminosity of 36 inverse picobarns is analysed. A next-to-leading-order perturbative QCD calculation is compared to the measurements. A discrepancy is observed for regions of the phase space where the two photons have an azimuthal angle difference, Delta (phi), less than approximately 2.8.
Combined results are reported from searches for the standard model Higgs boson in proton–proton collisions at s= 7 TeV in five Higgs boson decay modes: γγ, bb, ττ, WW, and ZZ. The explored Higgs boson mass range is 110–600 GeV. The... more
Combined results are reported from searches for the standard model Higgs boson in proton–proton collisions at s= 7 TeV in five Higgs boson decay modes: γγ, bb, ττ, WW, and ZZ. The explored Higgs boson mass range is 110–600 GeV. The analysed data correspond to an integrated luminosity of 4.6–4.8 fb− 1. The expected excluded mass range in the absence of the standard model Higgs boson is 118–543 GeV at 95% CL.
We have searched in pp collisions at ps 1.8 TeV for events with three charged leptons and missing transverse energy. In the minimal supersymmetric standard model, we expect trilepton events from chargino-neutralino x6 1 x0 2 pair... more
We have searched in pp collisions at ps 1.8 TeV for events with three charged leptons and missing transverse energy. In the minimal supersymmetric standard model, we expect trilepton events from chargino-neutralino x6 1 x0 2 pair production, with subsequent decay into leptons. We observe no candidate e1e2e6, e1e2m6, e6m1m2, or m1m2m6 events in 106 pb21 integrated luminosity. We present limits on the sum of the branching ratios times cross section for the four channels: sx6 1 x0 2
Abstract A search for large extra spatial dimensions via virtual-graviton exchange in the diphoton channel has been carried out with the CMS detector at the LHC. No excess of events above the standard model expectations is found using a... more
Abstract A search for large extra spatial dimensions via virtual-graviton exchange in the diphoton channel has been carried out with the CMS detector at the LHC. No excess of events above the standard model expectations is found using a data sample collected in proton-proton collisions at TeV and corresponding to an integrated luminosity of 36 pb− 1.
We present new limits on resonant t" b production in p" p collisions at ffiffiffi sp ¼ 1: 96 TeV, using 1: 9 fbÀ1 of data recorded with the CDF II detector at the Fermilab Tevatron. We reconstruct a candidate t" b mass in events with a... more
We present new limits on resonant t" b production in p" p collisions at ffiffiffi sp ¼ 1: 96 TeV, using 1: 9 fbÀ1 of data recorded with the CDF II detector at the Fermilab Tevatron. We reconstruct a candidate t" b mass in events with a lepton, neutrino candidate, and two or three jets, and search for anomalous t" b production as modeled by W 0! t" b.
A search for pair production of first-generation scalar leptoquarks is performed in the final state containing two electrons and two jets using proton-proton collision data at ffiffiffi sp ¼ 7 TeV. The data sample used corresponds to an... more
A search for pair production of first-generation scalar leptoquarks is performed in the final state containing two electrons and two jets using proton-proton collision data at ffiffiffi sp ¼ 7 TeV. The data sample used corresponds to an integrated luminosity of 33 pb À1 collected with the CMS detector at the CERN LHC.
Within the standard model (SM), two-jet (dijet) events are produced in proton-antiproton (p" p) collisions predominantly from hard quantum chromodynamics (QCD) interactions of two partons. The fragmentation and hadronization of the... more
Within the standard model (SM), two-jet (dijet) events are produced in proton-antiproton (p" p) collisions predominantly from hard quantum chromodynamics (QCD) interactions of two partons. The fragmentation and hadronization of the outgoing partons produce hadronic jets. The dijet mass spectrum predicted by QCD falls smoothly and steeply with increasing dijet mass.
A search for supersymmetry with R-parity conservation in proton–proton collisions at a centre-of-mass energy of 7 TeV is presented. The data correspond to an integrated luminosity of 35 pb− 1 collected by the CMS experiment at the LHC.... more
A search for supersymmetry with R-parity conservation in proton–proton collisions at a centre-of-mass energy of 7 TeV is presented. The data correspond to an integrated luminosity of 35 pb− 1 collected by the CMS experiment at the LHC. The search is performed in events with jets and significant missing transverse energy, characteristic of the decays of heavy, pair-produced squarks and gluinos.