No abstract

We report the observation of a narrow state decaying into J/psipi+pi- and produced in 220 pb(-1) of p p-bar collisions at =1.96 Tesqaure root of sV in the CDF II experiment. We observe 730+/-90 decays. The mass is measured to be 3871.3+/-0.7(stat)+/-0.4(syst) MeV/c2, with an observed width consistent with the detector resolution. This is in agreement with the recent observation by the Belle Collaboration of the X(3872) meson.

We present a new measurement of the inclusive and differential production cross sections of J= mesons and b hadrons in proton-antiproton collisions at s p 1960 GeV. The data correspond to an integrated luminosity of 39:7 pb ÿ1 collected by the CDF run II detector. We find the integrated cross section for inclusive J= production for all transverse momenta from 0 to 20 GeV=c in the rapidity range jyj < 0:6 to be 4:08 0:02stat 0:36 ÿ0:33 syst b. We separate the fraction of J= events from the decay of the long-lived b hadrons using the lifetime distribution in all events with p T J= > 1:25 GeV=c. We find the total cross section for b hadrons, including both hadrons and antihadrons, decaying to J= with transverse momenta greater than 1:25 GeV=c in the rapidity range jyJ= j < 0:6 is 0:330 0:005stat 0:036 ÿ0:033 syst b. Using a Monte Carlo simulation of the decay kinematics of b hadrons to all final states containing a J= , we extract the first measurement of the total single b-hadron cross section down to zero transverse momentum at s p 1960 GeV. We find the total single b-hadron cross section integrated over all transverse momenta for b hadrons in the rapidity range jyj < 0:6 to be 17:6 0:4stat 2:5 ÿ2:3 syst b.

We report on measurements of the inclusive jet production cross section as a function of the jet transverse momentum in p p collisions at s p 1:96 TeV, using the k T algorithm and a data sample corresponding to 1:0 fb ÿ1 collected with the Collider Detector at Fermilab in run II. The measurements are carried out in five different jet rapidity regions with jy jet j < 2:1 and transverse momentum in the range

The top quark is the heaviest known elementary particle, with a mass about 40 times larger than the mass of its isospin partner, the bottom quark. It decays almost 100% of the time to a W boson and a bottom quark. Using top-antitop pairs at the Tevatron proton-antiproton collider, the CDF and D0 Collaborations have measured the top quark's mass in different final states for integrated luminosities of up to 5.8 fb −1 . This paper reports on a combination of these measurements that results in a more precise value of the mass than any individual decay channel can provide. It describes the treatment of the systematic uncertainties and their correlations. The mass value determined is 173.18 ± 0.56 (stat) ± 0.75 (syst) GeV or 173.18 ± 0.94 GeV, which has a precision of ±0.54%, making this the most precise determination of the top-quark mass.