An overview of the Electronics System for the BABAR Experiment, emphasizing architectural issues and development of new components, is presented. © 1998 Published by Elsevier Science B.V. All rights reserved.

Current topics in computing for data acquisition, control, and trigger systems for high energy physics experiments are discussed with emphasis on those topics presented in papers submitted to the International Conference on Computing in High Energy Physics, Berlin, April 7-11, 1997. © 1998 Published by Elsevier Science B.V.

Data acquisition (DAQ) electronics are described for a system of high-rate cathode strip chambers (CSC) in the forward region of A Toroidal LHC Apparatus (ATLAS) muon spectrometer. The system provides serial streams of control signals for switched capacitor array analog memories on the chambers and accepts a total of nearly 294 Gbit/s in serial raw data streams from 64 chambers in the design configuration. Processing of the data is done in two stages, leading to an output bandwidth of 2.56 Gbit/s. The architecture of the system is described, as are some important signal processing algorithms and hardware implementation details. Although designed for a specific application, the architecture is sufficiently general to be used in other contexts.

We have searched 205 pb-1 of s =29 GeV data from the Mark II detector at the SLAC e+e- storage ring PEP for events which may signify the existence of a new lepton pair (L-,L0) where the L0 may be massive, but does not exceed the L- mass. Three event signatures for L+L- decay are examined: (i) e, (ii) (e or)(+4), and (iii) (e or )(3+0). The numbers of signature events are found to be in good agreement with Monte Carlo simulations of known background sources. The ranges of L- and L0 masses for which new lepton pairs are excluded are obtained using a likelihood-ratio method to compare the number of observed signature events to the expected background, and to the expected background plus Monte Carlo predictions of (L-,L0) signals. © 1989 The American Physical Society.

The ATLAS muon Cathode Strip Chamber (CSC) backend readout system has been upgraded during the LHC 2013-2015 shutdown to be able to handle the higher Level-1 trigger rate of 100 kHz and the higher occupancy at Run-2 luminosity. The readout design is based on the Reconfigurable Cluster Element (RCE) concept for high bandwidth generic DAQ implemented on the Advanced Telecommunication Computing Architecture (ATCA) platform. The RCE design is based on the new System on Chip XILINX ZYNQ series with a processor-centric architecture with ARM processor embedded in FPGA fabric and high speed I/O resources. Together with auxiliary memories, all these components form a versatile DAQ building block that can host applications tapping into both software and firmware resources. The Cluster on Board (COB) ATCA carrier hosts RCE mezzanines and an embedded Fulcrum network switch to form an online DAQ processing cluster. More compact firmware solutions on the ZYNQ for high speed input and output fiberoptic links and TTC allowed the full system of 320 input links from the 32 chambers to be processed by 6 COBs in one ATCA shelf. The full system was installed in September 2014. We will present the RCE/COB design concept, the firmware and software processing architecture, and the experience from the intense commissioning for LHC Run 2.

The τ lifetime was measured with the Mark II vertex detector at the storage ring PEP. ττ=(3.20±0.41±0.35)×10-13 sec was found, which agrees well with e-μ-τ university. © 1983 The American Physical Society.

In a study of (3684) radiative decays with the Mark II detector at SPEAR, the decay sequence c (2980) is observed, with the c (2980) decaying into several completely reconstructed hadronic modes. A mass M=29808 MeV/c2 and a width <40 MeV/c2 (90%) confidence level) are obtained, and estimates of some of the decay branching ratios are presented. © 1980 The American Physical Society.

The inclusive and 0 momentum distributions at the have been measured. Using these data and estimates of production, it is found that (4.1 0.8)% of decays contain a direct photon with energy greater than 60% of the beam energy. The expected momentum distribution for direct photons calculated to lowest order in quantum chromodynamics is qualitatively different from that observed in the data. © 1980 The American Physical Society.

The branching fractions for the major decay modes of the lepton are measured from a sample of tagged decays selected from +- pairs produced in e+e- annihilation. The decay products of one member of the +- pair are used to identify the event. The opposite member of the pair is then included in the sample if it satisfies an invariant-mass cut and a charged-multiplicity cut. In this way, we attempt to select an unbiased sample of decays. The sample is divided into categories based on charged- and neutral-particle multiplicities, and charged-particle identification. The branching fractions are measured simultaneously, with an unfold technique and a maximum-likelihood fit, with the sum of the branching fractions constrained to be unity. The branching fractions for the decay modes - K- and - K*- are fixed at the world averages in the fit. The following branching fractions are measured: B(-e) =(19.10.81.1)%, B(-' - )=(18.30.90.8)%, B(-) =(10.01.1 *1,4)%, B(-0) =(25.81.72.5)%, B(-(n0, n>1))=(12.01.42.5)%, B(-+-) =(6.7 0.80.9)%, and B(-+- (n0,n>0)) =(6.10.80.9)%. The total branching fraction to one charged pion plus at least one neutral hadron is measured to be (37.81.21.0)%. Limits on allowed decay modes involving the meson are discussed. © 1987 The American Physical Society.