arXiv subjects

L. Cerrito

Publications and source records attributed to L. Cerrito.

81 records · Page 5Linked to original sources

arXiv2011

Measurement of branching ratio and Bs0 lifetime in the decay Bs0 -> J/psi f0(980) at CDF

We present a study of Bs0 decays to the CP-odd final state J/psi f0(980) with J/psi -> mu+ mu- and f0(980) -> pi+ pi-. Using ppbar collision data with an integrated luminosity of 3.8/fb collected by the CDF II detector at the Tevatron we measure a Bs0 lifetime of tau(Bs0 -> J/psi f0(980)) = 1.70 -0.11+0.12(stat) +-0.03(syst) ps. This is the first measurement of the Bs0 lifetime in a decay to a CP eigenstate and corresponds in the standard model to the lifetime of the heavy Bs0 eigenstate. We also measure the product of branching fractions of Bs0 -> J/psi f0(980) and f0(980) -> pi+ pi- relative to the product of branching fractions of Bs0 -> J/psi phi and phi -> K+ K- to be R_f0/phi = 0.257 +_0.020(stat) +-0.014(syst), which is the most precise determination of this quantity to date.

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arXiv2011

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

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 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 diphoton analysis, the RS-graviton lower mass limit for the coupling k/\bar{M}_{Pl}=0.1 is 1058 GeV/c^2, making it the strongest limit to date.

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arXiv2010

Top quark and Electroweak measurements at the Tevatron

We present recent preliminary measurements at the Tevatron of t-tbar and single top production cross section, top quark mass and width, top pair spin correlations and forward-backward asymmetry. In the electroweak sector, we present the Tevatron average of the W boson width, and preliminary measurements of the W and Z forward-backward asymmetries and WZ, ZZ diboson production cross sections. All measurements are based on larger amount of collision data than previously used and are in agreement with the standard model.

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arXiv2010

Studying the Underlying Event in Drell-Yan and High Transverse Momentum Jet Production at the Tevatron

We study the underlying event in proton-antiproton collisions by examining the behavior of charged particles (transverse momentum pT > 0.5 GeV/c, pseudorapidity |η| < 1) produced in association with large transverse momentum jets (~2.2 fb-1) or with Drell-Yan lepton-pairs (~2.7 fb-1) in the Z-boson mass region (70 < M(pair) < 110 GeV/c2) as measured by CDF at 1.96 TeV center-of-mass energy. We use the direction of the lepton-pair (in Drell-Yan production) or the leading jet (in high-pT jet production) in each event to define three regions of η-ϕspace; toward, away, and transverse, where ϕis the azimuthal scattering angle. For Drell-Yan production (excluding the leptons) both the toward and transverse regions are very sensitive to the underlying event. In high-pT jet production the transverse region is very sensitive to the underlying event and is separated into a MAX and MIN transverse region, which helps separate the hard component (initial and final-state radiation) from the beam-beam remnant and multiple parton interaction components of the scattering. The data are corrected to the particle level to remove detector effects and are then compared with several QCD Monte-Carlo models. The goal of this analysis is to provide data that can be used to test and improve the QCD Monte-Carlo models of the underlying event that are used to simulate hadron-hadron collisions.

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arXiv2009

Measurements of Top Quark Properties

Preliminary results on the measurement of four selected properties of the top quark are presented. The relative fraction of $t\bar{t}$ production through gluon fusion has been measured in the $t\bar{t}$ dilepton decay channel by the CDF Collaboration as $F_{gg}=0.53^{+0.36}_{-0.38}$. Using an integrated luminosity of 2.7 fb$^{-1}$ collected with the CDF II detector, we also determine the $t\bar{t}$ differential cross section with respect to values up to $\sim$1 TeV of the $t\bar{t}$ invariant mass. We present a model-independent measurement of the helicity of $W$ bosons produced in top quark decays, using an integrated luminosity of up to 2.7 fb$^{-1}$ collected by the D0 detector, and find the fraction of longitudinal $W$ bosons $f_0=0.49\pm0.14$, and the fraction of right-handed $W$ bosons $f_+=0.11\pm0.08$. Finally, we measure the parton level forward-backward asymmetry of pair produced top quarks using an integrated luminosity of 3.2 fb$^{-1}$ collected with the CDF II detector, and find $A_{FB}=0.19\pm0.07$. All results are consistent with the predictions of the standard model.

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arXiv2005

Search for First-Generation Scalar Leptoquarks in $\bm{p \bar{p}}$ collisions at $\sqrt{s}$=1.96 TeV

We report on a search for pair production of first-generation scalar leptoquarks ($LQ$) in $p \bar{p}$ collisions at $\sqrt{s}$=1.96 TeV using an integrated luminosity of 203 $pb^{-1}$ collected at the Fermilab Tevatron collider by the CDF experiment. We observe no evidence for $LQ$ production in the topologies arising from $LQ \bar{LQ} \to eqeq$ and $LQ \bar{LQ} \to eq νq$, and derive 95% C.L. upper limits on the $LQ$ production cross section. %as a function of $β$, where $β$ is the branching fraction for $LQ \to eq$. The results are combined with those obtained from a separately reported CDF search in the topology arising from $LQ\bar{LQ} \to νq νq$ and 95% C.L. lower limits on the LQ mass as a function of $β= BR(LQ \to eq) $ are derived. The limits are 236, 205 and 145 GeV/c$^2$ for $β$ = 1, $β$ = 0.5 and $β$ = 0.1, respectively.

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arXiv2004

Comparison of Three-jet Events in Proton-Antiproton Collisions at Center-of-mass Energy 1.8 TeV to Predictions from a Next-to-leading Order QCD Calculation

The properties of three-jet events with total transverse energy greater than 320 GeV and individual jet energy greater than 20 GeV have been analyzed and compared to absolute predictions from a next-to-leading order (NLO) perturbative QCD calculation. These data, of integrated luminosity 86 pb^-1, were recorded by the CDF Experiment for proton-antiproton collisions at sqrt{s}=1.8 TeV. This study tests a model of higher order QCD processes that result in gluon emission and can be used to estimate the magnitude of the contribution of processes higher than NLO. The total cross section is measured to be 466 +/- 3(stat.)^{+207}_{-70}(syst.) pb. The differential cross section is furthermore measured for all kinematically accessible regions of the Dalitz plane, including those for which the theoretical prediction is unreliable. While the measured cross section is consistent with the theoretical prediction in magnitude, the two differ somewhat in shape in the Dalitz plane.

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arXiv2004

Top Quark Mass Measurements

Preliminary results on the measurement of the top quark mass (mt) at the Tevatron Collider are presented. In the dilepton decay channel, the CDF Collaboration measures mt=175.0(+17.4)(-16.9)(stat.)+/-8.4(syst.) GeV/c2, using a sample of ~126 pb-1 of proton-antiproton collision data at sqrt(s)=1.96 TeV (Run II). In the lepton plus jets channel, the CDF Collaboration measures 177.5(+12.7)(-9.4)(stat.)+/-7.1(syst.) GeV/c2, using a sample of ~102 pb-1 at sqrt(s)=1.96 TeV. The D0 Collaboration has newly applied a likelihood technique to improve the analysis of ~125 pb-1 of proton-antiproton collisions at sqrt(s)=1.8 TeV (Run I), with the result: mt=180.1+/-3.6(stat.)+/-3.9(syst.) GeV/c2. The latter is combined with all the measurements based on the data collected in Run I to yield the most recent and comprehensive experimental determination of the top quark mass: mt=178.0+/-2.7(stat.)+/-3.3(syst.) GeV/c2

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arXiv2003

Measurement of the polar-angle distribution of leptons from W boson decay as a function of the W transverse momentum in proton-antiproton collisions at sqrt{s}=1.8 TeV

We present a measurement of the coefficient alpha_2 of the leptonic polar-angle distribution from W boson decays, as a function of the W transverse momentum. The measurement uses an 80+/-4 pb^{-1} sample of proton-antiproton collisions at sqrt{s}=1.8 TeV collected by the CDF detector and includes data from both the W->e+nu and W->mu+nu decay channels. We fit the W boson transverse mass distribution to a set of templates from a Monte Carlo event generator and detector simulation in several ranges of the W transverse momentum. The measurement agrees with the Standard Model expectation, whereby the ratio of longitudinally to transversely polarized W bosons, in the Collins-Soper W rest frame, increases with the W transverse momentum at a rate of approximately 15% per 10 GeV/c.

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