A Low-cost Multi-channel Analogue Signal Generator

A scalable multi-channel analogue signal generator is presented. It uses a commercial low-cost graphics card with multiple outputs in a standard PC as signal source. Each color signal serves as independent channel to generate an analogue signal. A custom-built external PCB was developed to adjust the graphics card output voltage levels for a specific task, which needed differential signals. The system furthermore comprises a software package to program the signal shape. The signal generator was successfully used as independent test bed for the ATLAS Level-1 Trigger Pre-Processor, providing up to 16 analogue signals

A Low-cost Multi-channel Analogue Signal Generator

A scalable multi-channel analogue signal generator is presented. It uses a commercial low-cost graphics card with multiple outputs in a standard PC as signal source. Each color signal serves as independent channel to generate an analogue signal. A custom-built external PCB was developed to adjust the graphics card output voltage levels for a specific task, which needed differential signals. The system furthermore comprises a software package to program the signal shape. The implementation of the signal generator is presented as well as an application where it was successfully utilized

A Low-cost Multi-channel Analogue Signal Generator

A scalable multi-channel analogue signal generator is presented. It uses a commercial low-cost graphics card with multiple outputs in a standard PC as signal source. Each color signal serves as independent channel to generate an analogue signal. A custom-built external PCB was developed to adjust the graphics card output voltage levels for a specific task, which needed differential signals. The system furthermore comprises a software package to program the signal shape. The implementation of the signal generator is presented as well as an application where it was successfully utilized

Observation of B+->Lambda_c+Lambda_c-K+ and B0->Lambda_c+Lambda_c^-K0 decays

We report first measurements of the doubly charmed baryonic B decays B->Lambda_c+Lambda_c-K. The B+->Lambda_c+Lambda_c-K+ decay is observed with a branching fraction of (6.5+1.0-0.9+-1.1+-3.4)x10^{-4} and a statistical significance of 15.4sigma. The B0->Lambda_c+Lambda_c-K0 decay is observed with a branching fraction of (7.9+2.9-2.3+-1.2+-4.2)x10^{-4} and a statistical significance of 6.6sigma. The branching fraction errors are statistical, systematic, and the error resulting from the uncertainty of Lambda_c+->pK-pi+ decay branching fraction. The analysis is based on 357fb-1 of data accumulated at the Y(4S) resonance with the Belle detector at the KEKB asymmetric e+e- collider.Comment: 10 pages, 3 figure

Towards testing a two-Higgs-doublet model with maximal CP symmetry at the LHC: construction of a Monte Carlo event generator

A Monte Carlo event generator is constructed for a two-Higgs-doublet model with maximal CP symmetry, the MCPM. The model contains five physical Higgs bosons; the $\rho'$, behaving similarly to the standard-model Higgs boson, two extra neutral bosons $h'$ and $h"$, and a charged pair $H^\pm$. The special feature of the MCPM is that, concerning the Yukawa couplings, the bosons $h'$, $h"$ and $H^\pm$ couple directly only to the second generation fermions but with strengths given by the third-generation-fermion masses. Our event generator allows the simulation of the Drell-Yan-type production processes of $h'$, $h"$ and $H^\pm$ in proton-proton collisions at LHC energies. Also the subsequent leptonic decays of these bosons into the $\mu^+ \mu^-$, $\mu^+ \nu_\mu$ and $\mu^- \bar \nu_\mu$ channels are studied as well as the dominant background processes. We estimate the integrated luminosities needed in $p p$ collisions at center-of-mass energies of 8 TeV and 14 TeV for significant observations of the Higgs bosons $h'$, $h"$ and $H^\pm$ in these muonic channels

Measurement of phi_3 with Dalitz plot analysis of B+ -> D(*)K(*)+ decay

We present a measurement of the unitarity triangle angle phi_3 using a Dalitz plot analysis of the K0_S pi+ pi- decay of the neutral D meson from the B+- -> D(*)K(*)+- process. The method employs the interference between D0 and D0bar to extract the angle phi_3, strong phase Delta and the ratio r of suppressed and allowed amplitudes. We apply this method to a 357 fb-1 data sample collected by the Belle experiment. The analysis uses three modes: B+ -> DK+, B+ -> D*K+ with D* -> Dpi0, and B+ -> DK*+ with K*+ -> K0_S pi+, as well as the corresponding charge-conjugate modes. From a combined maximum likelihood fit to the three modes, we obtain phi_3=53+15-18(stat)+-3(syst)+-9(model) degrees. The corresponding two standard deviation interval is 8<phi_3<111 degrees.Comment: 18 pages, 6 figures, 7 tables. To be submitted to Phys. Rev.

Measurements of CP Violation in B0→D∗−π+B^0 \to D^{*-}\pi^+ and B0→D−π+B^0 \to D^- \pi^+ Decays

We report measurements of time dependent decay rates for $B^0 \to D^{(*)-}\pi^+$ decays and extraction of CP violation parameters that depend on $\phi_3$. Using fully reconstructed $D^{(*)}\pi$ events and partially reconstructed $D^{*}\pi$ events from a data sample that contains 386 million $B\bar{B}$ pairs that was collected near the $\Upsilon(4S)$ resonance, with the Belle detector at the KEKB asymmetric energy $e^+ e^-$ collider, we obtain the CP violation parameters $S^+ (D^{(*)}\pi)$ and $S^- (D^{(*)}\pi)$. We obtain $S^+ (D^* \pi) = 0.049 \pm 0.020(\mathrm{stat}) \pm 0.011(\mathrm{sys})$, $S^- (D^* \pi) = 0.031 \pm 0.019(\mathrm{stat}) \pm 0.011(\mathrm{sys})$, and $S^+ (D \pi) = 0.031 \pm 0.030(\mathrm{stat}) \pm 0.012(\mathrm{sys})$, $S^- (D \pi) = 0.068 \pm 0.029(\mathrm{stat}) \pm 0.012(\mathrm{sys})$. These results are an indication of CP violation in $B^0 \to D^{*-}\pi^+$ and $B^0 \to D^- \pi^+$ decays at the $2.5 \sigma$ and $2.2 \sigma$ levels, respectively. If we use the values of $R_{D^{(*)}\pi}$ that are derived using assumptions of factorization and SU(3) symmetry, the branching fraction measurements for the $D_s^{(*)} \pi$ modes, and lattice QCD calculations, we can restrict the allowed region of $|\sin (2\phi_1 + \phi_3)|$ to be above 0.44 and 0.52 at 68% confidence level from the $D^* \pi$ and $D \pi$ modes, respectively.Comment: 14 pages, 12 figures, submitted to Physical Review

Study of B+- --> D_CP K+- and D^*_CP K+- decays

We report a study of the modes D_CP K+- and D^*_CP K+- where D^(*) decays to CP eigenstates. The data sample used contains 275 x 10^6 BB events at the Upsilon(4S) resonance collected by the Belle detector at the KEKB energy-asymmetric e^+ e^- collider. The CP asymmetries obtained for D_CP K are: A_1 = 0.06 +- 0.14 (stat) +- 0.05 (sys), A_2 = -0.12 +- 0.14 (stat) +- 0.05 (sys) and for D^*_CP K : A_1^* = -0.20 +- 0.22 (stat) +- 0.04 (sys), A_2^* = 0.13 +- 0.30 (stat) +- 0.08 (sys).Comment: 10 pages, 7 figures, submitted to Phys.Rev.D (Rapid Communications

Observation of B+ -> proton Lambdabar gamma

We report the first observation of the radiative hyperonic B decay B+ -> proton Lambdabar gamma, using a 140 fb-1 data sample recorded on the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric energy e+e- collider. The measured branching fraction is B(B+ -> proton Lambdabar gamma) = (2.16 ^{+0.58}_{-0.53} +- 0.20) times 10^{-6}. A search for B+ -> proton Sigmabar gamma yields no significant signal, so we set a 90% confidence-level upper limit on the branching fraction of B(B+ -> proton Sigmabar gamma) < 3.3 times 10^{-6}.Comment: 12 pages, 4 figures, submitted to ICHEP2004, Beijing, Chin

Pion and proton showers in the CALICE scintillator-steel analogue hadron calorimeter

Showers produced by positive hadrons in the highly granular CALICE scintillator-steel analogue hadron calorimeter were studied. The experimental data were collected at CERN and FNAL for single particles with initial momenta from 10 to 80 GeV/c. The calorimeter response and resolution and spatial characteristics of shower development for proton- and pion-induced showers for test beam data and simulations using Geant4 version 9.6 are compared.Comment: 26 pages, 16 figures, JINST style, changes in the author list, typos corrected, new section added, figures regrouped. Accepted for publication in JINS