Heavy flavour physics from top to bottom

We review the status of heavy flavour physics at the Fermilab Tevatron collider by summarizing recent top quark and B physics results from CDF and D0. In particular we discuss the measurement of the top quark mass and top production cross section as well as B meson lifetimes and time dependent B{bar B} mixing results. An outlook of perspectives for top and B physics in Run II starting in 1999 is also given. 38 refs., 23 figs., 8 tabs

Pojedinačna tvorba top kvarkova sudaračem Fermilab Tevatron

First evidence for single top quark production has recently been found by both the D0 and CDF experiments. By combining three analyses, D0 measured a cross section of σ(pp¯ → tb + X, tqb + X) = 4.7 ± 1.3 pb, with a significance of 3.6 standard deviations, and CDF’s matrix elements analysis measured a cross section of σ (pp¯ → tb + X, tqb + X) = 3.0 +1.2 −1.1 pb, with a significance of 3.1 standard deviations. These analyses also provided the first direct measurements of the CKM matrix element, |Vtb|, without assuming unitarity. This paper briefly describes the latest single top production results from the two experiments.U nedavnim smo mjerenjima D0 i CDF našli prve podatke o tvorbi pojedinačnih top kvarkova. Spajanjem triju analiza, mjerenja D0 dala su udarni presjek σ(pp¯ → tb+ X, tqb+ X) = 4.7±1.3 pb, na razini pouzdanosti 3.6 standardne devijacije, dok su mjerenja CDF analizom matričnih elemenata odredila udarni presjek σ (pp¯ → tb + X, tqb + X) = 3.0 +1.2 −1.1 pb na razini pouzdanosti 3.1 standardne devijacije. Te su analize također dale prvo izravno određivanje CKM matričnog elementa, |Vtb|, bez pretpostavke unitarnosti. U ovom se radu opisuju najnoviji ishodi tvorbe pojedinačnih top kvarkova u tim dvama mjerenjima

Re-evaluation of the LHC potential for the measurement of Mw

We present a study of the LHC sensitivity to the W boson mass based on simulation studies. We find that both experimental and phenomenological sources of systematic uncertainties can be strongly constrained with Z measurements: the lineshape is robustly predicted, and its analysis provides an accurate measurement of the detector resolution and absolute scale, while the differential cross-section analysis absorbs most of the strong interaction uncertainties. A sensitivity \delta Mw \sim 7 \MeV for each decay channel (W --> e nu, W --> mu nu), and for an integrated luminosity of 10 fb-1, appears as a reasonable goal

Low-mass fermiophobic charged Higgs phenomenology in two-Higgs-doublet models

After the recent discovery of a Higgs-like boson, the possibility of an enlarged scalar sector arises as a natural question. Experimental searches for charged scalars have been already performed with negative results. We analyze the phenomenology associated with a fermiophobic charged Higgs (it does not couple to fermions at tree level), in two-Higgs-doublet models. All present experimental bounds are evaded trivially in this case, and one needs to consider other decay and production channels. We study the associated production of a charged Higgs with either a W or a neutral scalar boson, and the relevant decays for a light fermiophobic charged Higgs. The interesting features of this scenario should result encouraging for the LHC collaborations to perform searches for such a particle

Measurement of the t(t)over-bar production cross section in the all-jet final state in pp collisions at √s=7 TeV

This article is the pre-print version of the final published paper that is available from the link below.A measurement is presented of the tt production cross section (σtt) in protonproton collisions at a centre-of-mass energy of 7TeV, in the all-jet final state that contains at least six jets, two of which are tagged as originating from b quarks. The data correspond to an integrated luminosity of 3.54 fb-1, collected with the CMS detector at the LHC. The cross section is determined through an unbinned maximum likelihood fit of background and tt signal to the reconstructed mass spectrum of tt candidates in the data, in which events are subjected to a kinematic fit assuming a tt → W+bW-b → 6 jets hypothesis. The measurement yields σtt = 139±10 (stat.) ±26 (syst.) ±3 (lum.) pb, a result consistent with those obtained in other tt decay channels, as well as with predictions of the standard model

Quarkonium production in proton antiproton collisions at the Tevatron

Charmonium and bottomonium production is studied using {mu}{sup +}{mu}{sup -} data samples collected by the CDF and D{null} experiments during the 1992-96 {ital p{anti p}} collider run at the Fermilab Tevatron. The inclusive cross sections as a function of the transverse momentum of reconstructed quarkonium states are measured. The results are compared with theoretical predictions, which take into account different quarkonium production mechanisms

Photons and diphotons from the Tevatron

Photon measurements from the CDF and D0 collaboration are described. The subjects touched on are loosely organized around the fact that they all have some bearing on the structure functions and pQCD. The methodology of collider measurements is briefly reviewed, and the results for single photons, photons plus jets, photons plus charm and diphotons are discussed. Finally there is a very brief indication of what is expected from the Tevatron based experiments in the future