53456374
Operational experience with the DIRC detector
The DIRC, a novel type of Cherenkov ring imaging device, is the primary hadronic particle identification system for the BABAR detector at the asymmetric B-factory, PEP-II at the Stanford Linear Accelerator Center. It is based on total internal reflection and uses long, rectangular bars made from synthetic fused silica as Cherenkov radiators and light guides. BABAR began taking data with colliding beams in late spring 1999. This paper describes the performance of the DIRC during the first 2.5 years of operation.
126404399
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
160033287
Improved Measurement of CP Violation in Neutral B Decays to c cs
125343210
Measurement of the CKM matrix element $|V_{ub}|$ with $B \to \rho e \nu$ decays
120104270
Operation of the Cherenkov detector DIRC of BABAR at high luminosity
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.
202048438
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
17599988
EXACT SOLUTION OF LONG-RANGE INTERACTING SPIN CHAINS WITH BOUNDARIES
We consider integrable models of the Haldane-Shastry type with open boundary conditions. We define monodromy matrices, obeying the reflection equation, which generate the symmetries of these models. Using a map to the Calogero-Sutherland Hamiltonian of BC type, we derive the spectrum and the highest weight eigenstates.
18392219
AFFINE SOLITONS: A RELATION BETWEEN TAU FUNCTIONS, DRESSING AND BÄCKLUND TRANSFORMATIONS
We reconsider the construction of solitons by dressing transformations in the sine-Gordon model. We show that the N-soliton solutions are in the orbit of the vacuum, and we identify the elements in the dressing group which allow us to build the N-soliton solutions from the vacuum solution. The dressed τ functions can be computed in two different ways: either using adjoint actions in the affine Lie algebra , and this gives the relation with the Backlund transformations, or using the level-one representations of the affine Lie algebra , and this directly gives the formulae for the τ functions in terms of vertex operators.
120847571
Residual quantum symmetries of the Restricted sine-Gordon theories
Various aspects of the Restricted sine-Gordon (RSG) theories for the coupling β28π = pp+1 are examined. The particle spectrum is interpreted in terms of generalized kinks for the RSG potential, which is shown to effectively contain p−1 degenerate vacua. Simple arguments based on a study of the topological charge show that in the massless limit the RSG theories reduce to the Feigin-Fuchs construction. We find that the RSG S-matrices are characterized by a symmetry which generalizes supersymmetry to a fractional supersymmetry, and that the particles have fractional spin and statistics. In accordance with these results, we find some non-local chiral algebras in the minimal models that generalize the superconformal algebra, and whose currents are conserved in perturbation theory.
936612
Strong–weak coupling duality in anisotropic current interactions
Abstract The recently proposed all orders β function for current interactions in two dimensions is further investigated. By using a strong–weak coupling duality of the β function, and some added topology of the space of couplings we are able to extend the flows to arbitrarily large or small scales. Using a nontrivial RG invariant we are able to identify sine-Gordon, sinh-Gordon and Kosterlitz–Thouless phases. We also find an additional phase with cyclic or roaming RG trajectories.
33626790
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.