120152123
Particle physics at the turn of the century
Aspects of particle physics are reviewed from an experimental viewpoint. The elementary constituents of the Universe are described, as are the fundamental forces through which they interact. Recent results are emphasized and there is some speculation about the future. No attempt has been made to give a complete bibliography, but a few references to recent reviews and original articles are given. A glossary of acronyms is included.
125004264
Measurement of polarization in K−p elastic scattering between 0.955 GeV/c and 1.272 GeV/c
The polarization parameter has been measured for K−p elastic scattering at nine incident beam momenta between 0.955 and 1.272 GeV/c covering the c.m. angular range −0.9 < cos θ∗ < + 0.9. Experimental results and coefficients of Legendre polynomial fits to the data are presented and compared with other measurements and a partial-wave analysis.
120177817
Performance of a UA1 Hadron Calorimeter Prototype
The hadron calorimeter for the UA1 experiment at the CERN SPS proton-antiproton collider consists of a lead-scintillator sandwich plus an iron-scintillator sandwich with wavelength shifter readout. We have tested prototype modules in muon and hadron beams in the momentum range from 0.7 to 90 GeV/c. For several angles of incidence, we have studied the uniformity of the response to hadrons as a function of position. This has included regions where there is reduced sensitivity due to mechanical constraints and the presence of the wavelength shifter readout. The response, resolution and degree of shower containment were measured as a function of incident momentum.
117635066
LOW-MOMENTUM ANTIPROTON PRODUCTION AT THE CERN PROTON SYNCHROTRON.
123331390
Experimental techniques in particle physics
Abstract The great majority of experiments in particle physics use beams of particles from accelerators. Individual interactions of these with other particles are observed by detector systems. Fixed target and colliding beam experiments are contrasted, and non-accelerator experiments mentioned briefly. An account is given of the principles of the various detectors. These include scintillation and Cerenkov counters and the various tracking devices such as bubble chambers, proportional and drift chambers. Calorimeters have emerged recently as important detectors at the highest energies. Electronic logic modules are mentioned and the main steps in data acquisition and analysis are described. Finally an example is given of a large detector system.
124176528
Wide-angle proton-proton elastic scattering from 1.3 to 3.0 GeV/c
SummaryDifferential cross-sections for proton-proton elastic scattering have been measured covering the angular range from 50° to 90° c.m. at twelve incident momenta from 1.3 to 3.0 GeV/c. The angular distributions are quite smooth, but there is evidence of structure in the energy dependence of fixed-angle cross-sections at |t| ∼ 1 (GeV)2.RiassuntoSi sono misurate le sezioni d’urto differenziali per lo scattering elastico protone-protone coprendo l’intervallo angolare da 50° a 90° c.m. a dodici impulsi incidenti da 1.3 a 3.0 GeV/c. Le distribuzioni angolari sono abbastanza lineari, ma si hanno prove di una struttura nella dipendenza dell’energia dalle sezioni d’urto ad angolo fisso per |t| ∼ 1 (GeV)2.РеэюмеБыли иэмерены дифференциальные поперечные сечения протон-протонного упругого рассеяния в области углов от 50° до 90° в системе центра масс при двенадцати эначениях начальных импульсов от 1.3 до З.ОГзВ/с. Угловые распределения являются довольно плавными, но обнаружена структура в знергетической эависимости поперечных сечений при фиксированном угле при |t| ∼ 1 (ГзВ)2.
11311944
Precise calibration of LIGO test mass actuators using photon radiation pressure
Precise calibration of kilometer-scale interferometric gravitational wave detectors is crucial for source localization and waveform reconstruction. A technique that uses the radiation pressure of a power-modulated auxiliary laser to induce calibrated displacements of one of the ~10 kg arm cavity mirrors, a so-called photon calibrator, has been demonstrated previously and has recently been implemented on the LIGO detectors. In this paper, we discuss the inherent precision and accuracy of the LIGO photon calibrators and several improvements that have been developed to reduce the estimated voice coil actuator calibration uncertainties to less than 2% (1σ). These improvements include accounting for rotation-induced apparent length variations caused by interferometer and photon calibrator beam centering offsets, absolute laser power measurement using temperature-controlled InGaAs photodetectors mounted on integrating spheres and calibrated by NIST, minimizing errors induced by localized elastic deformation of the mirror surface by using a two-beam configuration with the photon calibrator beams symmetrically displaced about the center of the optic and simultaneously actuating the test mass with voice coil actuators and the photon calibrator to minimize fluctuations caused by the changing interferometer response. The photon calibrator is able to operate in the most sensitive interferometer configuration, and is expected to become a primary calibration method for future gravitational wave searches.
14608151
X-Pipeline: an analysis package for autonomous gravitational-wave burst searches
Autonomous gravitational-wave searches—fully automated analyses of data that run without human intervention or assistance—are desirable for a number of reasons. They are necessary for the rapid identification of gravitational-wave burst candidates, which in turn will allow for follow-up observations by other observatories and the maximum exploitation of their scientific potential. A fully automated analysis would also circumvent the traditional 'by hand' setup and tuning of burst searches that is both labourious and time consuming. We demonstrate a fully automated search with X-Pipeline, a software package for the coherent analysis of data from networks of interferometers for detecting bursts associated with gamma-ray bursts (GRBs) and other astrophysical triggers. We discuss the methods X-Pipeline uses for automated running, including background estimation, efficiency studies, unbiased optimal tuning of search thresholds and prediction of upper limits. These are all done automatically via Monte Carlo with multiple independent data samples and without requiring human intervention. As a demonstration of the power of this approach, we apply X-Pipeline to LIGO data to compute the sensitivity to gravitational-wave emission associated with GRB 031108. We find that X-Pipeline is sensitive to signals approximately a factor of 2 weaker in amplitude than those detectable by the cross-correlation technique used in LIGO searches to date. We conclude with comments on the status of X-Pipeline as a fully autonomous, near-real-time-triggered burst search in the current LSC-Virgo Science Run.
36815013
Prospects of gravitational wave data mining and exploration via evolutionary computing
Techniques of evolutionary computing have proven useful for a diverse array of fields in science and engineering. Because of the expected low signal to noise ratio of LIGO data and incomplete knowledge of gravitational waveforms, evolutionary computing is an excellent candidate for LIGO data analysis studies. Using the evolutionary computing methods of genetic algorithms and genetic programming, we have developed, as a proof of principle, search algorithms that are effective at finding sine-gaussian signals hidden in noise while maintaining a small false alarm rate. Because we used realistic LIGO noise as a training ground, the algorithms we have evolved should be well suited to detecting signals in actual LIGO data, as well as in simulated noise. These algorithms have continuously improved during the five days of their evolution and are expected to improve further the more they are evolved. The top performing algorithms from generation 100 and 199 were benchmarked using gaussian white noise to illustrate their performance and the improvement over 100 generations.
117574348
Excluding Source Models with Multiple Astrophysical Observations
We describe a general method to observationally exclude a theoretical model for gravitational wave (GW) emission from a transient astrophysical source (event) by using a null detection from a network of GW detectors. In the case of multiple astrophysical events with no GW detection, statements about individual events can be combined to increase the exclusion confidence. We frame and demonstrate the method using a population of hypothetical core collapse supernovae.