Showing papers by "Kostantinos Kordas published in 2005"
TL;DR: In this paper, the authors presented a new measurement of the inclusive and differential production cross sections of J/psi mesons and b-hadrons in proton-antiproton collisions at {radical}s = 1960 GeV The data correspond to an integrated luminosity of 397 pb{sup -1} collected by the CDF Run II detector.
Abstract: The authors present a new measurement of the inclusive and differential production cross sections of J/{psi} mesons and b-hadrons in proton-antiproton collisions at {radical}s = 1960 GeV The data correspond to an integrated luminosity of 397 pb{sup -1} collected by the CDF Run II detector They find the integrated cross section for inclusive J/{psi} production for all transverse momenta from 0 to 20 GeV/c in the rapidity range |y| 125 GeV/c They find the total cross section for b-hadrons, including both hadrons and anti-hadrons, decaying to J/{psi} with transverse momenta greater than 125 GeV/c in the rapidity range |y(J/{psi})| < 06, is 0330 {+-} 0005(stat){sub -0033}{sup +0036}(syst) {mu}b Using a Monte Carlo simulation of the decay kinematics of b-hadrons to all final states containing a J/{psi}, they extract the first measurement of the total single b-hadron cross section down to zero transverse momentum at {radical}s = 1960 GeV They find the total single b-hadron cross section integrated over all transverse momenta for b-hadrons in themore » rapidity range |y| < 06 to be 176 {+-} 04(stat){sub -23}{sup +25}(syst) {mu}b« less
382 citations
TL;DR: In this article, a measurement of the tt production cross section using events with one charged lepton and jets from pp collisions at a center-of-mass energy of 1.96 TeV is presented.
Abstract: We present a measurement of the tt production cross section using events with one charged lepton and jets from pp collisions at a center-of-mass energy of 1.96 TeV. In these events, heavy flavor quarks from top quark decay are identified with a secondary vertex tagging algorithm. From 162 pb{sup -1} of data collected by the Collider Detector at Fermilab, a total of 48 candidate events are selected, where 13.5{+-}1.8 events are expected from background contributions. We measure a tt production cross section of 5.6{sub -1.1}{sup +1.2}(stat.){sub -0.6}{sup +0.9}(syst.) pb.
119 citations
TL;DR: In this article, the authors report on a study of jet shapes in inclusive jet production in $p\overline{p}$ collisions at $\sqrt{s}=1.96\text{ }\mathrm{TeV}$ using the upgraded collider detector at Fermilab in Run II (CDF II) and based on an integrated luminosity of $170
Abstract: We report on a study of jet shapes in inclusive jet production in $p\overline{p}$ collisions at $\sqrt{s}=1.96\text{ }\mathrm{TeV}$ using the upgraded collider detector at Fermilab in Run II (CDF II) and based on an integrated luminosity of $170\text{ }\mathrm{p}{\mathrm{b}}^{\ensuremath{-}1}$. Measurements are carried out on jets with rapidity $0.1l|{Y}^{\mathrm{jet}}|l0.7$ and transverse momentum $37\text{ }\text{ }\mathrm{GeV}/cl{P}_{T}^{\mathrm{jet}}l380\text{ }\text{ }\mathrm{GeV}/c$. The jets have been corrected to the hadron level. The measured jet shapes are compared to leading-order QCD parton-shower Monte Carlo predictions as implemented in the PYTHIA and HERWIG programs. PYTHIA, tuned to describe the underlying event as measured in CDF Run I, provides a better description of the measured jet shapes than does PYTHIA or HERWIG with their default parameters.
83 citations
TL;DR: The first measurements of inclusive W and Z cross sections times leptonic branching ratios for pp collisions at square root[s]=1.96 TeV are reported, based on their decays to electrons and muons.
Abstract: We report the first measurements of inclusive W and Z cross sections times leptonic branching ratios for p (p) over bar collisions at root s=1.96 TeV, based on their decays to electrons and muons. The data correspond to an integrated luminosity of 72 pb(-1) recorded with the CDF detector at the Fermilab Tevatron. We test e-mu universality in W decays, and we measure the ratio of leptonic W and Z rates from which the leptonic branching fraction B(W -> l nu) can be extracted as well as an indirect value for the total width of the W and the Cabibbo-Kobayashi-Maskawa matrix element, vertical bar V(cs)vertical bar.
66 citations
TL;DR: In this paper, the lifetimes and polarization amplitudes for B(0)(s) and B(d) were measured for the first time by determining the relative contributions of amplitudes with definite CP as a function of the decay time.
Abstract: We present measurements of the lifetimes and polarization amplitudes for B(0)(s)-->J/psiphi and B(0)(d)-->J/psiK(*0) decays. Lifetimes of the heavy and light mass eigenstates in the B(0)(s) system are separately measured for the first time by determining the relative contributions of amplitudes with definite CP as a function of the decay time. Using 203+/-15 B(0)(s) decays we obtain tau(L) = (1.05(+0.16)(-0.13) +/- 0.02) ps and tau(H) = (2.07(+0.58)(-0.46) +/- 0.03) ps. Expressed in terms of the difference DeltaGamma(s) and average Gamma(s), of the decay rates of the two eigenstates, the results are DeltaGamma(s)/Gamma(s) = (65(+25)(-33) +/- 1)% and DeltaGamma(s) = (0.47(+0.19)(-0.24) +/- 0.01) ps(-1).
62 citations
TL;DR: In this article, the forward-backward charge asymmetry of electrons from W boson decays in pp collisions at √s=1.96 TeV using a data sample of 170 pb-1 collected by the Collider Detector at Fermilab.
Abstract: We report a measurement of the forward-backward charge asymmetry of electrons from W boson decays in pp collisions at √s=1.96 TeV using a data sample of 170 pb-1 collected by the Collider Detector at Fermilab. The asymmetry is measured as a function of electron rapidity and transverse energy and provides new input on the momentum fraction dependence of the u and d quark parton distribution functions within the proton. © 2005 The American Physical Society.
60 citations
TL;DR: In this article, the first two moments of the hadronic invariant mass-squared distribution in charmed semileptonic B decays were measured using 180 pb{sup -1} of data collected with the CDF II detector at the Tevatron.
Abstract: Using 180 pb{sup -1} of data collected with the CDF II detector at the Tevatron, we measure the first two moments of the hadronic invariant mass-squared distribution in charmed semileptonic B decays. From these we determine the non-perturbative Heavy Quark Effective Theory parameters {Lambda} and {lambda}{sub 1} used to relate the B meson semileptonic branching ratio to the CKM matrix element |V{sub cb}|.
60 citations
TL;DR: In this article, the authors used 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.
Abstract: We present a measurement of the top pair production cross section in $p\overline{p}$ collisions at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$. We collect a data sample with an integrated luminosity of $194\ifmmode\pm\else\textpm\fi{}11\text{ }\text{ }{\mathrm{pb}}^{\ensuremath{-}1}$ 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 ${\ensuremath{\sigma}}_{t\overline{t}}=6.6\ifmmode\pm\else\textpm\fi{}1.1\ifmmode\pm\else\textpm\fi{}1.5\text{ }\text{ }\mathrm{pb}$, where the first uncertainty is statistical and the second is systematic.
36 citations
TL;DR: In this paper, a search for standard model t-channel and s-channel single-top quark production in pp collisions at the center of mass energy of 1.96 TeV was conducted.
Abstract: We report on a search for standard model t-channel and s-channel single-top quark production in pp collisions at a center of mass energy of 1.96 TeV. We use a data sample corresponding to 162 pb-1 recorded by the upgraded collider detector at Fermilab. We find no significant evidence for electroweak top quark production and set upper limits at the 95% confidence level on the production cross section, consistent with the standard model: 10.1 pb for the t-channel, 13.6 pb for the s-channel and 17.8 pb for the combined cross section of t- and s-channel. © 2005 The American Physical Society.
35 citations
TL;DR: In this paper, a measurement of the $t\overline{t}$ production cross section using CDF II data using events with a high transverse momentum electron or muon, three or more jets, and missing transverse energy.
Abstract: We present a measurement of the $t\overline{t}$ production cross section using $194\text{ }{\mathrm{pb}}^{\ensuremath{-}1}$ of CDF II data using events with a high transverse momentum electron or muon, three or more jets, and missing transverse energy. The measurement assumes 100% $t\ensuremath{\rightarrow}Wb$ branching fraction. Events consistent with $t\overline{t}$ decay are found by identifying jets containing heavy-flavor semileptonic decays to muons. The dominant backgrounds are evaluated directly from the data. Based on 20 candidate events and an expected background of $9.5\ifmmode\pm\else\textpm\fi{}1.1$ events, we measure a production cross section of $5.3\ifmmode\pm\else\textpm\fi{}{3.3}_{\ensuremath{-}1.0}^{+1.3}\text{ }\mathrm{pb}$, in agreement with the standard model.
33 citations
TL;DR: In this paper, a measurement of the rate of prompt diphoton production in pp collisions at 1.96 TeV using a data sample of 207 pb 1 collected with the upgraded Collider Detector at Fermilab is reported.
Abstract: We report a measurement of the rate of prompt diphoton production in pp collisions at 1.96 TeV using a data sample of 207 pb 1 collected with the upgraded Collider Detector at Fermilab. The background from nonprompt sources is determined using a statistical method based on differences in the electromagnetic showers. The cross section is measured as a function of the diphoton mass, the transverse momentum of the diphoton system, and the azimuthal angle between the two photons and is found to be consistent with perturbative QCD predictions. © 2005 The American Physical Society.
TL;DR: A measurement of relative partial widths and decay rate CP asymmetries in K-K+ and pi(-)pi(+) decays of D0 mesons produced in pp collisions at sqrt[s]=1.96 TeV is presented.
Abstract: We present a measurement of relative partial widths and decay rate CP asymmetries in K- K+ and π-π+ decays of D0 mesons produced in pp collisions at,√s = 1.96 TeV. We use a sample of 2 × 105 D*+ →D0π+ (and charge conjugate) decays with the D0 decaying to K-π+, K-K +, and π-π+, 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 γ(D0→ K- K +)/γ(D0-→K-π+) = 0.0992 ±0.0992 ±0.0012, γ(D0→K -π+)/γ(D0→K -π+) = 0.03594 ± 0.00054 ±0.00040, A CP(K- K+) = (2.0 ±1.2 ±0.6)%, and ACP(π-π+) = (1.0 ±1.3 ±0.6)%, where, in all cases, the first uncertainty is statistical and the second is systematic. © 2005 The American Physical Society.
TL;DR: In this article, a search for excited and exotic electrons (e*) decaying to an electron and a photon, both with high transverse momentum, was presented, but no signal above standard model expectation is seen for associated ee(*) production.
Abstract: We present a search for excited and exotic electrons (e(*)) decaying to an electron and a photon, both with high transverse momentum. We use 202 pb(-1) of data collected in pp collisions at sqrt[s] = 1.96 TeV with the Collider Detector at Fermilab II detector. No signal above standard model expectation is seen for associated ee(*) production. We discuss the e(*) sensitivity in the parameter space of the excited electron mass M(e(*)) and the compositeness energy scale Lambda. In the contact interaction model, we exclude 132 GeV/c(2)
TL;DR: In this article, a search for pair production of first-generation scalar leptoquarks (LQ) in p (p) over bar collisions at root s=1.96 TeV using an integrated luminosity of 252 pb(-1) collected at the Fermilab Tevatron collider by the D0 detector was conducted.
Abstract: We report on a search for pair production of first-generation scalar leptoquarks (LQ) in p (p) over bar collisions at root s=1.96 TeV using an integrated luminosity of 252 pb(-1) collected at the Fermilab Tevatron collider by the D0 detector. We observe no evidence for LQ production in the topologies arising from LQ(LQ) over bar -> eqeq and LQ(LQ) over bar -> eq nu q, and derive 95% C.L. lower limits on the LQ mass as a function of beta, where beta is the branching fraction for LQ -> eq. The limits are 241 and 218 GeV/c(2) for beta=1 and 0.5, respectively. These results are combined with those obtained by D0 at root s=1.8 TeV, which increases these LQ mass limits to 256 and 234 GeV/c(2).
TL;DR: In this article, the results of a search for anomalous production of diphoton events with large missing transverse energy using the Collider Detector at Fermilab were presented.
Abstract: We present the results of a search for anomalous production of diphoton events with large missing transverse energy using the Collider Detector at Fermilab. In 202 pb(-1) of p (p) over bar collisions at s=1.96 TeV we observe no candidate events, with an expected standard model background of 0.27+/-0.07(stat)+/-0.10(syst) events. The results exclude a lightest chargino of mass less than 167 GeV/c(2), and lightest neutralino of mass less than 93 GeV/c(2) at 95% C.L. in a gauge-mediated supersymmetry-breaking model with a light gravitino.
TL;DR: In this paper, a measurement of the tt production cross section using the CDF II detector at the Fermilab Tevatron is reported, which is consistent with the standard model prediction.
Abstract: We report a measurement of the tt production cross section using the CDF II detector at the Fermilab Tevatron. The data consist of events with an energetic electron or muon, missing transverse energy, and three or more hadronic jets, at least one of which is identified as a b-quark jet by reconstructing a secondary vertex. The background fraction is determined from a fit of the transverse energy of the leading jet. Using 162 ± 10 pb -1 of data, the total cross section is found to be 6.0 ± 1.6(stat.) ± 1.2(syst.) pb, which is consistent with the standard model prediction. © 2005 The American Physical Society.
Michigan State University1, University of Lisbon2, University of Wisconsin-Madison3, University of Bern4, Argonne National Laboratory5, CERN6, University of Pavia7, Royal Holloway, University of London8, Shinshu University9, University of Mannheim10, University of Manchester11, University of California, Irvine12, Brookhaven National Laboratory13, Hiroshima Institute of Technology14, Rutherford Appleton Laboratory15, KEK16
TL;DR: A discussion of the functionality and real-time properties of the ROS is combined with a presentation of measurement and modeling results for a testbed with a size of about 20% of the final DAQ system, together with extrapolations to the full system.
Abstract: In the ATLAS experiment at the LHC, the output of readout hardware specific to each subdetector will be transmitted to buffers, located on custom made PCI cards ("ROBINs"). The data consist of fragments of events accepted by the first-level trigger at a maximum rate of 100 kHz. Groups of four ROBINs will be hosted in about 150 read-out subsystem (ROS) PCs. Event data are forwarded on request via Gigabit Ethernet links and switches to the second-level trigger or to the event builder. In this paper a discussion of the functionality and real-time properties of the ROS is combined with a presentation of measurement and modeling results for a testbed with a size of about 20% of the final DAQ system. Experimental results on strategies for optimizing the system performance, such as utilization of different network architectures and network transfer protocols, are presented for the testbed, together with extrapolations to the full system
TL;DR: In this paper, the standard model predictions for W γ and Z γ production were tested using an integrated luminosity of 200 pb -1 of pp collision data collected at the Collider Detector at Fermilab.
Abstract: The standard model predictions for W γ and Z γ production are tested using an integrated luminosity of 200 pb -1 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 E T > 7 GeV that are well separated from leptons. The production cross sections and kinematic distributions for the W γ and Z γ data are compared to SM predictions. © 2005 The American Physical Society.
TL;DR: In this article, a search for the pair production of scalar leptoquarks (LQ) was conducted using collision data recorded by the CDF experiment during Run II of the Tevatron.
Abstract: We report on a search for the pair production of scalar leptoquarks (LQ), using $191\text{ }\text{ }{\mathrm{pb}}^{\ensuremath{-}1}$ of proton-antiproton 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 $\ensuremath{\sigma}(p\overline{p}\ensuremath{\rightarrow}\mathrm{LQ}\overline{\mathrm{LQ}}X\ensuremath{\rightarrow}\ensuremath{
u}\overline{\ensuremath{
u}}q\overline{q}X)$. Using a next-to-leading order theoretical prediction of the cross section for LQ production, we exclude first-generation LQ in the mass interval 78 to $117\text{ }\text{ }\mathrm{GeV}/{c}^{2}$ at the 95% confidence level for $BR(\mathrm{LQ}\ensuremath{\rightarrow}\ensuremath{
u}q)=100%$.
TL;DR: In this paper, the authors reported on a search for λ ∆ ∆ baryons in p collisions at {radical}(s)=1.96 TeV using 193 pb{sup -1} of data collected by the Fermilab Tevatron Collider.
Abstract: We report on a search for {lambda}{sub b}{sup 0}{yields}p{pi}{sup -} and {lambda}{sub b}{sup 0}{yields}pK{sup -} (and charge conjugate) decays in pp collisions at {radical}(s)=1.96 TeV using 193 pb{sup -1} of data collected by the CDF II experiment at the Fermilab Tevatron Collider. Data were collected using a track trigger that has been optimized to select tracks belonging to a secondary vertex that is typical of two-body charmless decays of b-flavored hadrons, including {lambda}{sub b}{sup 0} baryons. As no {lambda}{sub b}{sup 0} signal was observed, we set the upper limits on the branching fraction B({lambda}{sub b}{sup 0}{yields}ph{sup -}), where h is K or {pi}, of 2.3x10{sup -5} at 90% C.L. and 2.9x10{sup -5} at 95% C.L.
TL;DR: In this article, a search for ZZ and ZW vector boson pair production in pp collisions at s=1.96TeV using the leptonic decay channels was presented.
Abstract: We present a search for ZZ and ZW vector boson pair production in pp collisions at s=1.96TeV using the leptonic decay channels ZZ→llνν, ZZ→lll′l′, and ZW→lll′ν. In a data sample corresponding to an integrated luminosity of 194pb-1 collected with the Collider Detector at Fermilab, 3 candidate events are found with an expected background of 1.0±0.2 events. We set a 95% confidence level upper limit of 15.2pb on the cross section for ZZ plus ZW production, compared to the standard model prediction of 5.0±0.4pb. © 2005 The American Physical Society.