Measuring beauty production in Pb-Pb collisions at the LHC via single electrons in ALICE

We present the expected ALICE performance for the measurement of the p_t-differential cross section of electrons from beauty decays in central Pb-Pb collisions at the LHC.Comment: 4 pages, 2 figures, proceeding of poster presentation at "Quark Matter 2005

Searching For Anomalous τνW\tau \nu W Couplings

The capability of current and future measurements at low and high energy $e^+e^-$ colliders to probe for the existence of anomalous, CP conserving, $\tau \nu W$ dipole moment-type couplings is examined. At present, constraints on the universality of the tau charged and neutral current interactions as well as the shape of the $\tau \to \ell$ energy spectrum provide the strongest bounds on such anomalous couplings. The presence of these dipole moments are shown to influence, e.g., the extraction of $\alpha_s(m_\tau^2)$ from $\tau$ decays and can lead to apparent violations of CVC expectations.Comment: 24 pages, 9 figure

Tests of the Standard Model: W mass and WWZ Couplings

Recent tests of the electroweak Standard Model are reviewed, covering the precise measurements of Z decays at LEP I and SLC and measurements of fermion pair production at higher energies at LEP II. Special emphasis is given to new results on W physics from LEP and FNAL

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

Z-Decays to b Quarks and the Higgs Boson Mass

A model independent analysis of the most recent averages of precision electroweak data from LEP and SLD finds a 3$\sigma$ deviation of the parameter $A_b$ from the Standard Model prediction. The fitted value of $m_H$ shows a strong dependence on the inclusion or exclusion of b quark data, and the Standard Model fits have poor confidence levels of a few percent when the latter are included. The good fits obtained to lepton data, c quark data and the directly measured top quark mass, give $m_t = 171.2_{-3.8}^{+3.7}$ GeV and indicate that the Higgs boson mass is most likely less than 200 GeV.Comment: 15 pages, 3 figures, 6 table

R-values in Low Energy e^+e^- Annihilation

This presentation briefly summarizes the recent measurements of R-values in low energy e^+e^- annihilation. The new experiments aimed at reducing the uncertainties in R-values and performed with the upgraded Beijing Spectrometer (BESII) at Beijing Electron Positron Collider (BEPC) in Beijing and with CMD-2 and SND at VEEP-2M in Novosibirsk are reviewed and discussed.Comment: 17 pages, 10 figures, invited presentation at the XIX International Symposium on Lepton and Photon Interactions at High Energy, Stanford University, August 199

Precision W-boson and top-quark mass determinations at a muon collider

Precise determinations of the masses of the $W$ boson and of the top quark could stringently test the radiative structure of the Standard Model (SM) or provide evidence for new physics. We analyze the excellent prospects at a muon collider for measuring $M_W$ and $m_t$ in the $W^+W^-$ and $t\bar t$ threshold regions. With an integrated luminosity of 10 (100) fb$^{-1}$, the $W$-boson mass could be measured to a precision of 20 (6) MeV, and the top-quark mass to a precision of 200 (70) MeV, provided that theoretical and experimental systematics are understood. A measurement of $\Delta m_t=200$ MeV for fixed $M_W$ would constrain a 100 GeV SM Higgs mass within about $\pm 2$ GeV, while $\Delta M_W=6$ MeV for fixed $m_t$ would constrain $m_h$ to about $\pm 10$ GeV.Comment: 27 pages, 11 figures, postscript file available via anonymous ftp://ucdhep.ucdavis.edu/han/mumu/mwmt.p

Standard Model Physics at LEP

Selected topics on precision tests of the Standard Model of the Electroweak and the Strong Interaction at the LEP $e^+e^-$ collider are presented, including an update of the world summary of measurements of $\alpha_s$, representing the state of knowledge of summer 1999. This write-up of lecture notes consists of a reproduction of slides, pictures and tables, supplemented by a short descriptive text and a list of relevant references.Comment: lecture given at Intern. Summer School at Nijmegen, August 1999, 44 pages, 36 (mostly coloured) figures, LaTeX, needs crckapb.st

Analysis of charmonium production at fixed-target experiments in the NRQCD approach

We present an analysis of the existing data on charmonium hadro-production based on non-relativistic QCD (NRQCD) calculations at the next-to-leading order (NLO). All the data on J/psi and psi' production in fixed-target experiments and on pp collisions at low energy are included. We find that the amount of color octet contribution needed to describe the data is about 1/10 of that found at the Tevatron

Photon air showers at ultra-high energy and the photonuclear cross-section

Experimental conclusions from air shower observations on cosmic-ray photons above 10^19 eV are based on the comparison to detailed shower simulations. For the calculations, the photonuclear cross-section needs to be extrapolated over several orders of magnitude in energy. The uncertainty from the cross-section extrapolation translates into an uncertainty of the predicted shower features for primary photons and, thus, into uncertainties for a possible data interpretation. After briefly reviewing the current status of ultra-high energy photon studies, the impact of the uncertainty of the photonuclear cross-section for shower calculations is investigated. Estimates for the uncertainties in the main shower observables are provided. Photon discrimination is shown to be possible even for rapidly rising cross-sections. When photon-initiated showers are identified, it is argued that the sensitivity of photon shower observables to the photonuclear cross-section can in turn be exploited to constrain the cross-section at energies not accessible at colliders.Comment: Based on a talk presented at the international conference "From Colliders to Cosmic Rays", Prague, September 7-13 (2005