Recent Results on Heavy Flavours with ALEPH

The latest ALEPH measurements on heavy flavours are presented. In particular the measurements of V_ub, the B(b -> s gamma) and a study on the width difference between mass eigenstates in the B_s system are presented.Comment: 7 pages, RevTe

An investigation on the b quark mass

In this article I will review the measurements of the b quark mass performed by ALEPH and DELPHI and presented at the HEP99 Conference in Tampere. Very clean effects of the mass running are observed, even if a wide spread in the results and large systematic errors due to hadronization corrections prevent to extract an average value of the running b quark mass.Comment: 3 pages, 1 figure

CMS upgrades for SLHC

I will discuss the impact of the LHC luminosity upgrade on CMS detector. While most of the CMS can possibly cope with the increased luminosity, the Tracker must undergo a major redesign in technology both in terms of detector substrates as well as in the data transfer links. I will show the impact on CMS of reduced bunch length and machine elements close to the interaction point

Length dependence of thermal conductivity by approach-to-equilibrium molecular dynamics

The length dependence of the thermal conductivity over more than two decades is systematically studied for a range of materials, interatomic potentials and temperatures, by the atomistic approach-to-equilibrium molecular dynamics method (AEMD). By comparing the values of conductivity obtained for a given supercell length and maximum phonon mean-free-path (MFP), we find that such values are strongly correlated, demonstrating that the AEMD calculation with a supercell of finite length, actually probes the thermal conductivity corresponding to a maximum phonon MFP. As a consequence, the less pronounced length dependence usually observed for poorer thermal conductors, such as amorphous silica, is physically justified by their shorter average phonon MFP. Finally, we compare different analytical extrapolations of the conductivity to infinite length, and demonstrate that the frequently used Matthiessen rule is not applicable in AEMD. An alternative extrapolation more suitable for transient-time, finite-supercell simulations is derived. This approximation scheme can also be used to classify the quality of different interatomic potential models with respect to their capability of predicting the experimental thermal conductivity

mb from ALEPH and comparison with other LEP experiments

I will review the measurements of the $b$-quark mass performed by ALEPH and DELPHI. A large set of observables has been used together with detailed studies on jet algorithms. Very clear effects due to the $b$-quark mass running are observed. Comparing with the determinations at the $\Upsilon(4S)$ threshold, the measurements of the running $b$-quark mass at the $Z$ pole are consistent with the predicted evolution from QCD.Comment: 10 pages, 7 figures, submitted to QCD2000, Montpellier, Franc

Nonperturbative study of the two-frequency sine-Gordon model

The two-frequency sine-Gordon model is examined. The focus is mainly on the case when the ratio of the frequencies is 1/2, given the recent interest in the literature. We discuss the model both in a perturbative (form factor perturbation theory) and a nonperturbative (truncated conformal space approach) framework, and give particular attention to a phase transition conjectured earlier by Delfino and Mussardo. We give substantial evidence that the transition is of second order and that it is in the Ising universality class. Furthermore, we check the UV-IR operator correspondence and conjecture the phase diagram of the theory.Comment: Minor corrections, LaTeX2e, 39 pages, 26 figures (4 pslatex, 1 postscript and 21 eps