Recent Results on the Beat-Wave Acceleration Experiment with Nd Lasers at Ecole Polytechnique
We describe an experiment aimed to accelerate particles with a beat-wave generated in a Dz plasma by two NdYAG and Nd-YLF laser wavelengths. The 3 MeV incident electrons are produced by a Van de Graaff accelerator. The electron and laser beams are aligned with an optical transition radiator. The accelerated particles are analysed by a magnetic spectrograph and detected by an array of scintillatom and photomultipliers. Preliminary results show a clear signal of a few hundred electrons accelerated to about 3.4 MeV.

title: Measurements of branching fractions and CP-violating asymmetries in B-meson decays to the charmless two-body states K0 pi+, anti-K0 K+, and K0 anti-K0

title: Measurement of the CKM matrix element $|V_{ub}|$ with $B \to \rho e \nu$ decays

title: Branching fraction for $B^{+} \to \pi^0 \ell^{+} \nu$, measured in $\upsilon_{4S} \to B \bar{B}$ events tagged by $B^{-} \to D^0 \ell^{-}$ anti-v ($X$) decays

title: Operation of the Cherenkov detector DIRC of BABAR at high luminosity
abstract: The DIRC (acronym for Detection of Internally Reflected Cherenkov (light)) is the ring imaging Cherenkov detector of the BABAR detector at the PEP-II ring of SLAC. It provides the identification of pions, kaons and protons for momenta up to 4 GeV/c with high efficiency. This is needed to reconstruct CP-violating B-decay final states and to provide B-meson flavour tagging for time dependent asymmetry measurements. The DIRC radiators consists of long rectangular bars made of synthetic fused silica and the photon detector is a water tank equipped with an array of 10.752 conventional photomultipliers. At the end of the year 2000 BABAR has recorded about 22 million B~B pairs reaching the design luminosity of L=3/spl middot/10/sup 33//cm/sup 2/s. The ability to keep the beam background level low at highest collision rates and the long term reliability of the DIRC components during continuous data taking are requirements of BABAR to accomplish its physics program.

title: Improved Measurement of CP Violation in Neutral B Decays to c cs

title: A quasi-Hopf algebra interpretation of quantum 3-j and 6-j symbols and difference equations
abstract: We consider the universal solution of the Gervais-Neveu-Felder equation in the U q ( sl 2 ) case. We show that it has a quasi-Hopf algebra interpretation. We also recall its relation to quantum 3- j and 6- j symbols. Finally, we use this solution to build a q -deformation of the trigonometric Lame equation.

title: The Large N Random phase sine-Gordon model
abstract: At large distances and in the low-temperature phase, the quenched correlation functions in the 2d random phase sine-Gordon model have been argued to be of the form: , with = (T − Tc). However, renormalization group computations predict B ≠ 0, while variational approaches (which are supposed to be exact for models with a large number of components) give B = 0. We introduce a large-N version of the random phase sine-Gordon model. Using non-Abelian bosonization and renormalization group techniques, we show that the correlation functions of our models have the above form but with a coefficient B suppressed by a factor 1/N3 compared to A.

title: Twisted self-duality of dimensionally reduced gravity and vertex operators
abstract: The Geroch group, isomorphic to the SL(2, R ) affine Kac-Moody group, is an infinite-dimensional solution generating group of Einstein's equations with two surface orthogonal commuting Killing vectors. We introduce another solution generating group for these equations, the dressing group, and discuss its connection with the Geroch group. We show that it acts transitively on a dense subset of moduli space. We use a new Lax pair expressing a twisted self-duality of this system and we study the dressing problem associated to it. We also describe how to use vertex operators to solve the reduced Einstein's equations.

title: Some Simple (Integrable) Models of Fractional Statistics
abstract: In the first part, we introduce the notion of fractional statistics in the sense of Haldane. We illustrate it on simple models related to anyon physics and to integrable models solvable by the Bethe ansatz. In the second part, we describe the properties of the long-range interacting spin chains. We describe its infinite dimensional symmetry, and we explain how the fractional statistics of its elementary excitations is an echo of this symmetry. In the third part, we review recent results on the Yangian representation theory which emerged from the study of the integrable long-range interacting models.

title: EXCHANGE ALGEBRA AND EXOTIC SUPERSYMMETRY IN THE CHIRAL POTTS MODEL
abstract: We obtain an exchange algebra for the Chiral Potts model, the elements of which are linear in the parameters defining the rapidity curve. This enables us to connect the Chiral Potts model to a Uq(GL(2)) algebra. On the other hand, looking at the model from the S-matrix point of view relates it to a ZZN generalisation of the supersymmetric algebra.