CDF top physics

The authors present the latest results about top physics obtained by the CDF experiment at the Fermilab Tevatron collider. The data sample used for these analysis (about 110 pb{sup {minus}1}) represents almost the entire statistics collected by CDF during four years (1992--95) of data taking. This large data size has allowed detailed studies of top production and decay properties. The results discussed here include the determination of the top quark mass, the measurement of the production cross section, the study of the kinematics of the top events and a look at top decays

Proceedings of the Workshop on Monte Carlo's, Physics and Simulations at the LHC PART II

These proceedings collect the presentations given at the first three meetings of the INFN "Workshop on Monte Carlo's, Physics and Simulations at the LHC", held at the Frascati National Laboratories in 2006. The first part of these proceedings contains pedagogical introductions to several basic topics of both theoretical and experimental high pT LHC physics. The second part collects more specialised presentations.Comment: 157 pages, 136 figures; contribution by M. Grazzini has been adde

New physics with mirror particles

The introduction of mirror fermions with masses between the weak scale and 1 TeV could offer a dynamical origin to the standard-model electro-weak symmetry breaking mechanism. The purpose of this work is to study the dynamics needed in order to render models with such a fermion content phenomenologically acceptable.Comment: 28 LaTeX pages, to appear in the Journal of Physics

Regional differences of vitamin D deficiency in rheumatoid arthritis patients in Italy

Vitamin D deficiency is very common in patients with rheumatoid arthritis (RA). Aim of this study was to evaluate the prevalence of vitamin D deficiency among the different Italian regions and whether these variations are associated with different severity of the disease. The study includes 581 consecutive RA patients (464 women), not taking vitamin D supplements, from 22 Italian rheumatology centres uniformly distributed across Italy. Together with parameters of disease activity (disease activity score 28), functional impairment (activities of daily living and health assessment questionnaire disability index) and mean sun exposure time, all patients had serum 25-hydroxyvitamin D (25OHD) measured in a centralized laboratory. Vitamin D deficiency (25OHD level <20 ng/mL) was very frequent among RA patients; its prevalence was 60%, 52% and 38% in southern, central and northern Italy, respectively. Mean disease activity and disability scores were worse in southern regions of Italy. These scores were inversely related to 25OHD levels and this correlation remained statistically significant after adjusting for both body mass index (BMI) and sun exposure time. However, disease severity remained significantly higher in southern regions versus central-northern Italy after adjustment also for serum 25OHD levels, age and BMI. In RA Italian patients there are significant regional differences in the prevalence of vitamin D deficiency explained by different BMI, and sun exposure time, and inversely associated with disease activity and disability scores

Bottom Production

We review the prospects for bottom production physics at the LHC.Comment: 74 pages, Latex, 71 figures, to appear in the Report of the ``1999 CERN Workshop on SM physics (and more) at the LHC'', P. Nason, G. Ridolfi, O. Schneider G.F. Tartarelli, P. Vikas (conveners

Energy Linearity and Resolution of the ATLAS Electromagnetic Barrel Calorimeter in an Electron Test-Beam

A module of the ATLAS electromagnetic barrel liquid argon calorimeter was exposed to the CERN electron test-beam at the H8 beam line upgraded for precision momentum measurement. The available energies of the electron beam ranged from 10 to 245 GeV. The electron beam impinged at one point corresponding to a pseudo-rapidity of eta=0.687 and an azimuthal angle of phi=0.28 in the ATLAS coordinate system. A detailed study of several effects biasing the electron energy measurement allowed an energy reconstruction procedure to be developed that ensures a good linearity and a good resolution. Use is made of detailed Monte Carlo simulations based on Geant which describe the longitudinal and transverse shower profiles as well as the energy distributions. For electron energies between 15 GeV and 180 GeV the deviation of the measured incident electron energy over the beam energy is within 0.1%. The systematic uncertainty of the measurement is about 0.1% at low energies and negligible at high energies. The energy resolution is found to be about 10% sqrt(E) for the sampling term and about 0.2% for the local constant term

Position resolution and particle identification with the ATLAS EM calorimeter

In the years between 2000 and 2002 several pre-series and series modules of the ATLAS EM barrel and end-cap calorimeter were exposed to electron, photon and pion beams. The performance of the calorimeter with respect to its finely segmented first sampling has been studied. The polar angle resolution has been found to be in the range 50-60 mrad/sqrt(E (GeV)). The neutral pion rejection has been measured to be about 3.5 for 90% photon selection efficiency at pT=50 GeV/c. Electron-pion separation studies have indicated that a pion fake rate of (0.07-0.5)% can be achieved while maintaining 90% electron identification efficiency for energies up to 40 GeV.Comment: 32 pages, 22 figures, to be published in NIM

Hadron Energy Reconstruction for the ATLAS Calorimetry in the Framework of the Non-parametrical Method

This paper discusses hadron energy reconstruction for the ATLAS barrel prototype combined calorimeter (consisting of a lead-liquid argon electromagnetic part and an iron-scintillator hadronic part) in the framework of the non-parametrical method. The non-parametrical method utilizes only the known $e/h$ ratios and the electron calibration constants and does not require the determination of any parameters by a minimization technique. Thus, this technique lends itself to an easy use in a first level trigger. The reconstructed mean values of the hadron energies are within $\pm 1$ of the true values and the fractional energy resolution is $[(58\pm3)/\sqrt{E}+(2.5\pm0.3)$. The value of the $e/h$ ratio obtained for the electromagnetic compartment of the combined calorimeter is $1.74\pm0.04$ and agrees with the prediction that $e/h > 1.7$ for this electromagnetic calorimeter. Results of a study of the longitudinal hadronic shower development are also presented. The data have been taken in the H8 beam line of the CERN SPS using pions of energies from 10 to 300 GeV.Comment: 33 pages, 13 figures, Will be published in NIM