29 research outputs found
Measurement of the Lambda_b Lifetime in Lambda_b --> J/psi Lambda0 in p-pbar Collisions at sqrt(s)=1.96 TeV
We report a measurement of the Lambda_b lifetime in the exclusive decay
Lambda_b --> J/psi Lambda0 in p-pbar collisions at sqrt(s) = 1.96 TeV using an
integrated luminosity of 1.0 fb^{-1} of data collected by the CDF II detector
at the Fermilab Tevatron. Using fully reconstructed decays, we measure
tau(Lambda_b) = 1.593 ^{+0.083}_{-0.078} (stat.) +- 0.033 (syst.) ps. This is
the single most precise measurement of tau(Lambda_b) and is 3.2 sigma higher
than the current world average.Comment: 7 Pages, 2 Figures, 1 Table. Submitted to Phys. Rev. Let
Measurement of the Top Pair Production Cross Section in the Dilepton Decay Channel in ppbar Collisions at sqrt s = 1.96 TeV
Submitted to Phys. Rev. DA measurement of the \ttbar production cross section in \ppbar collisions at = 1.96 TeV using events with two leptons, missing transverse energy, and jets is reported. The data were collected with the CDF II Detector. The result in a data sample corresponding to an integrated luminosity 2.8 fb is: \sigma_{\ttbar} = 6.27 0.73(stat) 0.63(syst) 0.39(lum) pb. for an assumed top mass of 175 GeV/.A measurement of the tt̅ production cross section in pp̅ collisions at √s=1.96  TeV using events with two leptons, missing transverse energy, and jets is reported. The data were collected with the CDF II detector. The result in a data sample corresponding to an integrated luminosity 2.8  fb-1 is σtt̅ =6.27±0.73(stat)±0.63(syst)±0.39(lum)  pb. for an assumed top mass of 175  GeV/c2.Peer reviewe
Comparison between cloprostenol-induced and spontaneous oestrus fertility in dairy cows
A short calving to conception interval is of main importance to achieve high economic efficiency in dairy cow industry. In order to reduce this interval, several hormonal treatments have been put on the market, in which cloprostenol, a synthetic analogue of prostaglandin F2 (PGF2). The aim of this study was to compare fertility of cloprostenol-induced oestrus to that of spontaneous oestrus in dairy cows. In a group of 525 cows, 280 (treated group) were administered 0.5 mg cloprostenol i.m. after transrectal corpus luteum (CL) detection, and inseminated at detected oestrus during the following week. The other 245 cows (control group) were inseminated during spontaneous oestrus. Whey progesterone concentrations were checked at treatment and at insemination in order to remove from the study cows whose P4 levels indicate a non-functional CL, or a lack of luteolysis respectively. Moreover, cows that were not inseminated due to genital problems were also excluded from this study. Conception (59% vs 54.5%) and calving rates (93.7% vs 93%) were not significantly different between the two groups