W mass measurement with muons at SQRT.S. = 1.8 TeV

The mass of the W vector boson has been measured from an analysis of $W \to\ \mu\ \nu$ decays in the CDF detector at the Fermilab Tevatron $\bar p p$ collider. The mass is 79.90 $\pm$ 0.53(stat.) $\pm$ 0.31(sys.) $\pm$ 0.16(scale) GeV/c\sp2. When this result is combined with previous CDF measurements, sin\sp2\theta\sb{W} is determined to be 0.231 $\pm$ 0.008. These measurements place an upper bound on the mass of the unfound top quark.U of I OnlyETDs are only available to UIUC Users without author permissio

The Construction of the Low-beta Triplets for the LHC

The performance of the LHC depends critically on the low-b triplets, located on either side of the four interaction points. Each triplet consists of four superconducting quadrupole magnets, which must operate reliably at up to 215 T/m, sustain high heat loads and have an excellent field quality. A collaboration between CERN, Fermilab and KEK was set up in 1996 to design and build the triplet systems, and after nine years of joint effort the production will be completed in 2005. We retrace the main events of the project and present the performance of the low-b quadrupoles built by KEK and Fermilab and of other elements of the triplet. The assembly of the first triplet at CERN and plans for tunnel installation and commissioning in the LHC are also reported

Measurement of the D+D^+- Meson Production Cross Section at Low Transverse Momentum in ppˉp\bar{p} Collisions at s=1.96\sqrt{s}=1.96 TeV

International audienceWe report on a measurement of the D+-meson production cross section as a function of transverse momentum (pT) in proton-antiproton (pp¯) collisions at 1.96 TeV center-of-mass energy, using the full data set collected by the Collider Detector at Fermilab in Tevatron Run II and corresponding to 10  fb-1 of integrated luminosity. We use D+→K-π+π+ decays fully reconstructed in the central rapidity region |y|<1 with transverse momentum down to 1.5  GeV/c, a range previously unexplored in pp¯ collisions. Inelastic pp¯-scattering events are selected online using minimally biasing requirements followed by an optimized offline selection. The K-π+π+ mass distribution is used to identify the D+ signal, and the D+ transverse impact-parameter distribution is used to separate prompt production, occurring directly in the hard-scattering process, from secondary production from b-hadron decays. We obtain a prompt D+ signal of 2950 candidates corresponding to a total cross section σ(D+,1.5<pT<14.5  GeV/c,|y|<1)=71.9±6.8(stat)±9.3(syst)  μb. While the measured cross sections are consistent with theoretical estimates in each pT bin, the shape of the observed pT spectrum is softer than the expectation from quantum chromodynamics. The results are unique in pp¯ collisions and can improve the shape and uncertainties of future predictions