117621820
Track finding efficiency in BABAR
Abstract We describe several studies to measure the charged track reconstruction efficiency and asymmetry of the B A B AR detector. The first two studies measure the tracking efficiency of a charged particle using τ and initial state radiation decays. The third uses the τ decays to study the asymmetry in tracking, the fourth measures the tracking efficiency for low momentum tracks, and the last measures the reconstruction efficiency of K S 0 particles. The first section also examines the stability of the measurements vs. B A B AR running periods.
61135312
Portable software for distributed readout controllers and event builders in FASTBUS and VME
We report on software developed as part of the PAN-DA system to support the functions of front end readout controllers and event builders in multiprocessor, multilevel, distributed data acquisition systems. For the next generation data acquisition system we have undertaken to design and implement software tools that are easily transportable to new modules. The first implementation of this software is for Motorola 68K series processor boards in FASTBUS and VME and will be used in the Fermilab accelerator run at the beginning of 1990. We use a Real Time Kernel Operating System. The software provides general connectivity tools for control, diagnosis and monitoring. 17 refs., 7 figs.
121719814
An electromagnetic calorimeter for the small angle regions of the collider detector at Fermilab
Two large electromagnetic calorimeters have been built for the Collider Detector at Fermilab (CDF). These have been designed for use in the small angle regions in both the proton and the antiproton beam directions. Each calorimeter consists of 30 sampling layers of proportional tube chambers with cathode pad readout separated by lead sheets for a total thickness of 25.5 radiation lengths. Each proportional tube chamber is constructed using a novel technique in which the insulating side of the cathode pad board is bonded to the proportional tube walls using resistive epoxy. The measured energy response of the calorimeter is linear up to 160 GeV, and the measured energy resolution, σEE, is approximately 25%√E + 0.5%. The position resolution for single electrons varies between 1 and 4 mm depending on location in the calorimeter. The calorimeter offers good eπ discrimination, where typically the pion misidentification probability ƒπ → e < 0.5% for an electron identification efficiency ϵ90%.
117126887
A Search for Double Parton Interactions in 1.8-TeV Proton - Anti-Proton Collisions
17140866
Extracting longitudinal shower development information from crystal calorimetry plus tracking
arXiv:0711.1593v2 [physics.ins-det] 11 Apr 2008 Extracting longitudinal shower development information from crystal calorimetry plus tracking D.N. Brown a , J. Ilic b , G.B. Mohanty b a Lawrence b Department Berkeley National Laboratory, Berkeley, California 94720, USA of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom Abstract We present an approach to derive longitudinal shower development information from the longitudinally unsegmented B A B AR electromagnetic calorimeter by using tracking information. Our algorithm takes advantage of the good three- dimensional tracking resolution of B A B AR , which provides an independent geometric constraint on the shower as measured in the B A B AR crystal calorimeter. We show that adding the derived longitudinal shower development information to standard particle identiﬁcation algorithms signiﬁcantly improves the low-momentum separation of pions from electrons and muons. We also verify that the energy dependence of the electromagnetic shower development we measure is consistent with the prediction of a standard electromagnetic shower model. Key words: Particle Identiﬁcation, Longitudinal Shower Depth, Electromagnetic Calorimetry, Tracking PACS: 29.40.Gx, 29.40.Vj, 07.05.Kf 1. Introduction In present-day nuclear and particle physics ex- periments, inorganic scintillating crystals, such as NaI(Tl) and CsI(Tl), are often used to construct electromagnetic calorimeters when a precise mea- surement of the energy is required [1]. Crystal calorimeters can be ﬁnely segmented in the dimen- sion transverse to the shower development without sacriﬁcing energy resolution, thus providing a good measurement of the lateral shower development. However, engineering and energy resolution consid- erations prevent ﬁnely segmenting crystal calorime- ters along the direction of shower development. Both lateral and longitudinal shower development information are useful in charged particle identi- Email addresses: Dave Brown@lbl.gov (D.N. Brown), J.Ilic@warwick.ac.uk (J. Ilic), G.B.Mohanty@warwick.ac.uk (G.B. Mohanty). Preprint submitted to Elsevier Science ﬁcation (PID) algorithms, particularly in electron identiﬁcation. Because crystal calorimeters cannot provide direct longitudinal shower development in- formation, they lose an important input to particle identiﬁcation. In this paper, we present a technique in which longitudinal shower development information is indirectly extracted from a longitudinally unseg- mented crystal calorimeter in conjunction with a precise tracking system. This technique was devel- oped for use with the B A B AR [2] detector, but it can be applied at any detector which combines crystal calorimetry and precision tracking. It exploits the fact that B A B AR has a tracking system capable of precisely determining the three-dimensional trajec- tory of charged particles, and the fact that these trajectories are not in general collinear with the crystal axes. A similar algorithm has previously been used for sampling calorimeters with ﬁne lateral segmentation [3]. 11 April 2008
40634832
An Overview of the B A B AR Conditions Database
This paper presents special database software developed in the context of the BABAR experiment used to keep the detector alignments, calibrations constants, as well as other time-dependent records of the conditions under which the experimental events are taken.
119181202
Template banks to search for low-mass binary black holes in advanced gravitational-wave detectors
Coalescing binary black holes (BBHs) are among the most likely sources for the Laser Interferometer Gravitational-wave Observatory (LIGO) and its international partners Virgo and KAGRA. Optimal searches for BBHs require accurate waveforms for the signal model and effectual template banks that cover the mass space of interest. We investigate the ability of the second-order post-Newtonian TaylorF2 hexagonal template placement metric to construct an effectual template bank, if the template waveforms used are effective one body waveforms tuned to numerical relativity (EOBNRv2). We find that by combining the existing TaylorF2 placement metric with EOBNRv2 waveforms, we can construct an effectual search for BBHs with component masses in the range 3 Msolar = 2.68 radians, there is no significant loss in the total possible signal-to-noise ratio due to neglecting modes other than l = m = 2 in the template waveforms. For a source population uniformly distributed in spacial volume, over the entire sampled region of the component-mass space, the loss in detection rate (averaged over a uniform distribution of inclination angle and sky-location/polarization angles), remains below ~11%. For binaries with high mass-ratios \textit{and} 0.31 <= \iota <= 2.68, including higher order modes could increase the signal-to-noise ratio by as much as 8% in Advanced LIGO. Our results can be used to construct matched-filter searches in Advanced LIGO and Advanced Virgo.
110973
Searching for gravitational waves from binary coalescence
We describe the implementation of a search for gravitational waves from compact binary coalescences in LIGO and Virgo data. This all-sky, all-time, multidetector search for binary coalescence has been used to search data taken in recent LIGO and Virgo runs. The search is built around a matched filter analysis of the data, augmented by numerous signal consistency tests designed to distinguish artifacts of non-Gaussian detector noise from potential detections. We demonstrate the search performance using Gaussian noise and data from the fifth LIGO science run and demonstrate that the signal consistency tests are capable of mitigating the effect of non-Gaussian noise and providing a sensitivity comparable to that achieved in Gaussian noise.
15439869
A three-stage search for supermassive black-hole binaries in LISA data
Gravitational waves from the inspiral and coalescence of supermassive black-hole (SMBH) binaries with masses m1 ~ m2 ~ 10^6Modot are likely to be among the strongest sources for the Laser Interferometer Space Antenna (LISA). We describe a three-stage data-analysis pipeline designed to search for and measure the parameters of SMBH binaries in LISA data. The first stage uses a time–frequency track-search method to search for inspiral signals and provide a coarse estimate of the black-hole masses m1, m2 and the coalescence time of the binary tc. The second stage uses a sequence of matched-filter template banks, seeded by the first stage, to improve the measurement accuracy of the masses and coalescence time. Finally, a Markov chain Monte Carlo search is used to estimate all nine physical parameters of the binary (masses, coalescence time, distance, initial phase, sky position and orientation). Using results from the second stage substantially shortens the Markov chain burn-in time and allows us to determine the number of SMBH-binary signals in the data before starting parameter estimation. We demonstrate our analysis pipeline using simulated data from the first Mock LISA Data Challenge. We discuss our plan for improving this pipeline and the challenges that will be faced in real LISA data analysis.
1026408
Turduckening black holes: An Analytical and computational study
We provide a detailed analysis of several aspects of the turduckening technique for evolving black holes. At the analytical level we study the constraint propagation for a family of formulations of Einstein's field equations and identify under what conditions the turducken procedure is rigorously justified and under what conditions constraint violations will propagate to the outside of the black holes. We present high resolution spherically symmetric studies which verify our analytical predictions. Then we present three-dimensional simulations of single distorted black holes using different variations of the turduckening method and also the puncture method. We study the effect that these different methods have on the coordinate conditions, constraint violations, and extracted gravitational waves. We find that the waves agree up to small but nonvanishing differences, caused by escaping superluminal gauge modes. These differences become smaller with increasing detector location.
51039474
When can Gravitational-wave Observations Distinguish between Black Holes and Neutron Stars?
Gravitational-wave observations of compact binaries have the potential to uncover the distribution of masses and spins of black holes and neutron stars in the universe. Th e binary components’ physical parameters can be inferred from their effect on the phasing of the gravitati onal-wave signal, but a partial degeneracy between the components’ mass ratio and their spins limits our abilit y to measure the individual component masses. At the typical signal amplitudes expected by the Advanced Laser Interferometer Gravitational-wave Observatory (signal-to-noise ratios between 10 and 20), we show that it will in many cases be difficult to distinguish whether the components are neutron stars or black holes. We identify when the masses of the binary components could be unambiguously measured outside the range of current observations: a system with a chirp mass M � 0.871 M⊙ would unambiguously contain the smallest-mass neutron star observed, and a system with M � 2.786 M⊙ must contain a black hole. However, additional information would be needed to distinguish between a binary containing two 1.35 M⊙ neutron stars and an exotic neutron-star‐black-hole binar y. We also identify those configurations that could be unambiguously identified as bla ck-hole binaries, and show how the observation of an electromagnetic counterpart to a neutron-star‐black-h ole binary could be used to constrain the black-hole spin. Subject headings: black hole physics — gravitational waves — stars: neutron