High-angular-precision gamma-ray astronomy and polarimetry above the pair-creation threshold
We are developing a concept of a ``thin'' detector as a high-angular-precision telescope and polarimeter for cosmic γ-rays above the pair-creation threshold.

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

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

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: An insulating grid spacer for large-area MICROMEGAS chambers
abstract: We present a novel design for large-area gaseous detectors based on the MICROMEGAS technology. This technology incorporates an insulating grid, sandwiched between the micro-mesh and the anode-pad plane, which provides a uniform 200 μm amplification gap. The uniformity of the amplification gap thickness has been verified. The gain performances of the detector are presented and compared to the values obtained with detectors using cylindrical micro spacers. The new design presents several technical and financial advantages.

title: New Lax pair for 2D dimensionally reduced gravity
abstract: Using a Lax pair based on the affine SL(2,) Kac-Moody algebra, we solve two-dimensional reduced vacuum Einstein's equations. We obtain explicit determinant formulae for metric coefficients with no quadrature left. This Lax connection also allows a new approach to the Poisson algebra of two-dimensional reduced gravity. In particular, we show that it leads to pure c-number r-matrices and modified Yang-Baxter equations. We explain how one can construct classical observables within this framework.

title: Bosonic Kac-Moody string theories
abstract: We study the BRS cohomology of a bosonic string propagating on a group manifold, and we extract its algebraic structure. We also show how one-loop modular invariance can be obtained by combining the left and the right sectors.

title: Conformal Transformations and the SLE Partition
Function Martingale

abstract: We present an implementation in conformal field theory (CFT) of local
finite conformal transformations fixing a point. We give explicit constructions when
the fixed point is either the origin or the point at infinity. Both cases involve the
exponentiation of a Borel subalgebra of the Virasoro algebra. We use this to build
coherent state representations and to derive a close analog of Wick’s theorem for the
Virasoro algebra. This allows to compute the conformal partition function in non
trivial geometries obtained by removal of hulls from the upper half-plane. This is
then applied to stochastic Loewner evolutions (SLE). We give a rigorous derivation
of the equations, obtained previously by the authors, that connect the stochastic
Loewner equation to the representation theory of the Virasoro algebra. We give a
new proof that this construction enumerates all polynomial SLE martingales. When
one of the hulls removed from the upper half-plane is the SLE hull, we show that
the partition function reduces to a useful local martingale known to probabilists,
thereby unraveling its CFT origin.