Measurement of the Cabibbo-Kobayashi-Maskawa matrix element V(ub) with B-->rhoenu decays

We present a measurement of the branching fraction for the rare decays B-->rhoenu and extract a value for the magnitude of V(ub), one of the smallest elements of the Cabibbo-Kobayashi-Maskawa quark-mixing matrix. The results are given for five different calculations of form factors used to para-metrize the hadronic current in semileptonic decays. Using a sample of 55 x 10(6) BB meson pairs recorded with the BABAR detector at the PEP-II e(+)e(-) storage ring, we obtain B(B0-->rho(-)e(+)nu)=(3.29+/-0.42+/-0.47+/-0.55) x 10(-4) and |V(ub)|=(3.64+/-0.22+/-0.25(+0.39)(-0.56)) x 10(-3), where the uncertainties are statistical, systematic, and theoretical, respectively.     

Search for lepton-flavor and lepton-number violation in the decay tau(-) -->l-(+)h+(-)h'(-)

A search for lepton-flavor and lepton-number violation in the decay of the tau lepton into one charged lepton and two charged hadrons is performed using 221.4 fb(-1) of data collected at an e+e- center-of-mass energy of 10.58 GeV with the BABAR detector at the SLAC PEP-II storage ring. In all 14 decay modes considered, the observed data are compatible with background expectations, and upper limits are set in the range B(tau-->lhh')<(0.7 - 4.8) x 10(-7) at 90% confidence level.     

Measurements of branching fractions and Dalitz distributions for B0 --> D(*)+/-K0pi-/+ decays

We present measurements of the branching fractions for the three-body decays B0 --> D(*)-/+K0pi+/- and their resonant submodes B0 --> D(*)-/+K*+/-using a sample of approximately 88 x 10(6) BB pairs collected by the BABAR detector at the SLAC PEP-II asymmetric energy storage ring. We measure: B(B0 --> D-/+K0pi+/-) = (4.9 +/- 0.7stat +/- 0.5syst) x 10(-4), B(B0 --> D*-/+K0pi+/-) = (3.0 +/- 0.7stat +/- 0.3syst) x 10(-4), B(B0 --> D-/+K*+/-) = (4.6 +/- 0.6stat +/- 0.5syst) x 10(-4), B(B0 --> D*-/+K*+/-) = (3.2 +/- 0.6stat +/- 0.3syst) x 10(-4). From these measurements we determine the fractions of resonant events to be f(B0 --> D-/+K*+/-) = 0.63 +/- 0.08stat +/- 0.04syst and f(B0 --> D*-/+K*+/-) = 0.72 +/- 0.14stat +/-0.05syst.     

Search for decays of B0-->e+ e-, B0-->mu+ mu-, B0-->e +/- mu-/+

We present a search for the decays B0-->e+ e-, B0-->mu+ mu-, and B0-->e (+/-) mu (-/+) in data collected at the Upsilon(4S) resonance with the BABAR detector at the SLAC B Factory. Using a data set of 111 fb(-1), we find no evidence for a signal in any of the three channels investigated and set the following branching fraction upper limits at the 90% confidence level: B(B0-->e+ e-) < 6.1 x 10(-8), B(B0-->mu+ mu-) < 8.3 x 10(-8), and B(B0-->e (+/-) mu (-/+) )<18 x 10(-8).     

Measurements of branching fractions and time-dependent CP-violating asymmetries in B --> eta'K decays

We present measurements of the B --> eta(')K branching fractions; for B(+) --> eta(')K(+) we measure also the time-integrated charge asymmetry Alpha(ch), and for B(0) --> eta(')K(0)(S) the time-dependent CP-violation parameters S and C. The data sample corresponds to 232 x 10(6) BB pairs produced by e(+)e(-) annihilation at the Upsilon (4S). The results are Beta(B --> eta(')K(+)) = (68.9 +/- 2.0 +/- 3.2) x 10(-6), Beta(B(0) --> eta(')K(0)) = (67.4 +/- 3.2) x 10(-6), Alpha(ch) = 0.033 +/- 0.028 +/- 0.005, S = 0.30 +/- 0.140 +/- 0.02, and C = -0.21 +/- 0.10 +/- 0.02, where the first error quoted is statistical and the second is systematic.     

Search for the decay B+ --> K+nunu

We search for the rare flavor-changing neutral-current decay B(+)--> K(+)nunu in a data sample of 82 fb(-1) collected with the BABAR detector at the PEP-II B-factory. Signal events are selected by examining the properties of the system recoiling against either a reconstructed hadronic or semileptonic charged-B decay. Using these two independent samples we obtain a combined limit of B(B(+)-->K(+)nunu ) < 5.2 x 10(-5) at the 90% confidence level. In addition, by selecting for pions rather than kaons, we obtain a limit of B(B+-->pi(+)nunu) < 1.0 x 10(-4) using only the hadronic B reconstruction method.     

Improving Frequency Acquisition of a Costas Loop

A Costas loop for tracking a BPSK signal does not acquire when the initial frequency error is comparable to the loop bandwidth. This paper describes methods for deriving control proportional to frequency error so as to improve the frequency acquisition capability by an AFC augmentation. A composite AFC/Costas loop is realized by combining the individual loops. Pull-in from a frequency error much greater than the Costas loop bandwidth is now feasible. The increase in phase error due to the AFC capability is evaluated by a linearized analysis. If the bandwidth of the AFC portion is sufficiently narrow, the degradation is negligible. Improved frequency acquisition can also be realized by a simple modification of the Costas loop to remove the low-pass filter on the quadrature phase detector channel, with negligible degradation to phase tracking.     

INTREPID: an integrated network tool for routing, evaluation ofperformance, and interactive design

The network design problem discussed is that of selecting nodes and links in a network. This includes deciding where to place network processors and links and what capacity nodes and links to use at each location. At a higher level, these decisions also determine the network architecture. The focus is on a two-level network, backbone and local access. Although the selection of specific equipment or the detailed configuration of devices is not discussed, INTREPID is sufficiently fast and flexible to be of use in making such decisions. The principles used in the development of INTREPID and its components are described. A top-level view of INTREPID is followed by a discussion of the design flow, utility modules, and design algorithms. Experience with the tool is briefly described     

High energy predictions for ¯pp andpp elastic scattering and total cross sections

Predictions for thes behavior at high energies are made for¯pp andpp: the differential elastic scattering cross section dσ/dt vs.t, the squared 4-momentum transfer; the total elastic cross sectionσ _el; the nuclear slope parameterB; the curvature parameterC; ?, the ratio of the real to the imaginary portion of the forward scattering amplitude; and the total cross sectionσ _tot. A hybrid approach is employed in order to gain reliable predictions. The energy dependence of? andσ _tot is fixed by fittingpp and¯pp experimental data for? andσ _tot from 15 GeV toS¯ppS energies, using analytic amplitudes. The other quantities are found using the Chou-Yang model, where the total, cross section is fixed from the fit.