Precision testing the Standard Model

Internal consistency of the most sensitive electroweak measurements within the standard model framework is examined. Confirming an earlier observation on the separation of Z-pole asymmetry measurements into {\em hadronisation- free}and {\em hadronisation-sensitive}, the electroweak mixing angle derived using the former is in perfect agreement with the precision W mass. These two complimentary measurements of weak radiative corrections, when combined with the lower limit on Higgs mass, are incompatible with the measured top quark mass. To overcome this inconsistency, a scenario readily testable in Run-II at Tevatron is envisaged: an upward shift of the top quark mass by about 10 GeV ($\sim 2\sigma$). If, however, the improved top quark mass remains at its current value or the lower limit on Higgs mass moves up substantially, then abandoning the SM may become inevitable.Comment: 7 pages, 4 figure

Recent results from LEP

Recent results from the LEP collider at CERN are presented: on the identification of e/sup +/e/sup -/ to W/sup +/W/sup -/ and the determination of the W mass and width and limits on its anomalous couplings; the search for the standard model and non-minimal Higgs; search for SUSY and other new particles. Fits to all electroweak data leading to predictions of the Higgs mass within the standard model are presented. (11 refs)

Measurement of the underlying event activity at the LHC with √s = 7 TeV and comparison with √s = 0.9 TeV

A measurement of the underlying activity in events with a jet of transverse momentum in the several GeV region is performed in proton-proton collisions at √s = 0.9s=09 and 7 TeV, using data collected by the CMS experiment at the LHC. The production of charged particles with pseudorapidity |η|<2 and transverse momentum pT >0.5 GeV/c is studied in the azimuthal region transverse to that of the leading set of charged particles forming a track-jet. A significant growth of the average multiplicity and scalar-pT sum of the particles in the transverse region is observed with increasing pT of the leading track-jet, followed by a much slower rise above a few GeV/c. For track-jet pT larger than a few GeV/c, the activity in the transverse region is approximately doubled with a centre-of-mass energy increase from 0.9 to 7 TeV. Predictions of several QCD-inspired models as implemented in pythia are compared to the data

Performance of τ-lepton reconstruction and identification in CMS

The performance of τ-lepton reconstruction and identification algorithms is studied using a data sample of proton-proton collisions at √s = 7 TeV, corresponding to an integrated luminosity of 36 pb-1 collected with the CMS detector at the LHC. The τ leptons that decay into one or three charged hadrons, zero or more short-lived neutral hadrons, and a neutrino are identified using final-state particles reconstructed in the CMS tracker and electromagnetic calorimeter. The reconstruction efficiency of the algorithms is measured using τ leptons produced in Z-boson decays. The τ-lepton misidentification rates for jets and electrons are determined

Measurement of the underlying event activity at the LHC with √s = 7 TeV and comparison with √s = 0.9 TeV

A measurement of the underlying activity in scattering processes with a hard scale in the several GeV region is performed in proton-proton collisions at √s = 0.9 and 7 TeV, using data collected by the CMS experiment at the LHC. The production of charged particles with pseudorapidity |η| < 2 and transverse momentum pT > 0.5 GeV/c is studied in the azimuthal region transverse to that of the leading set of charged particles forming a track-jet. A significant growth of the average multiplicity and scalar-pT sum of the particles in the transverse region is observed with increasing pT of the leading track-jet, followed by a much slower rise above a few GeV/c. For track-jet pT larger than a few GeV/c, the activity in the transverse region is approximately doubled with a centre-of-mass energy increase from 0.9 to 7 TeV. Predictions of several QCD-inspired models as implemented in PYTHIA are compared to the data

Combining real and virtual Higgs boson mass constraints

Within the framework of the standard model we observe that there is a significant discrepancy between the most precise $Z$ boson decay asymmetry measurement and the limit from direct searches for Higgs boson production. Using methods inspired by the Particle Data Group we explore the possible effect on fits of the Higgs boson mass. In each case the central value and the 95% confidence level upper limit increase significantly relative to the conventional fit. The results suggest caution in drawing conclusions about the Higgs boson mass from the existing data.Comment: 11 pages, Latex. Citations are added and paper is otherwise reconciled with version to be published in Physical Review Letter

The Impact of σ(e+e−→hadrons)\sigma(e^+e^-\to {hadrons}) Measurements at Intermediate Energies on the Parameters of the Standard Model

We discuss the impact of precision measurements of $\sigma(e^+e^-\to {hadrons})$ in the center-of-mass range between 3 and 12 GeV, including improvements in the electronic widths of the narrow charmonium and bottonium resonances, on the determination of parameters of the Standard Model. In particular we discuss the impact of potential improvements on the extraction of the strong coupling constant $\alpha_s$, on the evaluation of the hadronic contributions to the electromagnetic coupling $\alpha(M_Z)$, and the determination of the charm and bottom quark masses.Comment: 8 page

A study on the protective effects of calcium channel blockers against anoxic brain damage

Introduction It is now widely accepted that a rapid neuronal influx of Ca2+ following cerebral ischaemia! hypoxia is intimately connected with the cascade of events- including activation of enzymes which give rise to the production of reactive oxygen species and nitric oxide, thereby leading to free-radical induced damage -which reseult in neuronal injury and death. It is also known that a burst of free radical generation I occurs during re-oxygenation of the tissues following a period,ofischaernialhypoxia as also a prolonged purturbation of the membrane functions continues after the perfusion/oxygenation has been restored, which leads to continued accumulnnon of calcium intracellularly ; resulting ultimately in delayed damage and death of the neurone. Estimation of lipid peroxidation products proviqes a reliable estimate of free radical induced damage to tissues, and has been widely used for this purpose

The Indirect Limit on the Standard Model Higgs Boson Mass from the Precision FERMILAB, LEP and SLD Data

Standard Model fits are performed on the most recent leptonic and b quark Z decay data from LEP and SLD, and FERMILAB data on top quark production, to obtain $m_t$ and $m_H$. Poor fits are obtained, with confidence levels $\simeq$ 2%. Removing the b quark data improves markedly the quality of the fits and reduces the 95% CL upper limit on $m_H$ by $\simeq$ 50 GeV.Comment: 6 pages 3 tables i figur