123687310
Antiproton--proton annihilation into charged pion and kaon pairs
Events of the type anti pp $Yields$ K$sup -$K$sup +$, $pi$$sup - $$pi$$sup +$ were studied at 0.79 to 2.43 GeV/c. Differential cross sections and Legendre coefficient ratios are shown. Resonances found as a result of model fitting showing spin--parity assignment versus mass squared are also shown. (JFP)
123678522
Options for machines and experiments in the future
The highest energy particle accelerators in operation and under construction are described briefly, together with a selection of detectors. Extrapolations of existing techniques both for accelerators and for detectors appear to be adequate for the next upward step in energy, but beyond this new techniques will probably have to be developed. Some predictions are given.
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.
118446989
Stacking gravitational wave signals from soft gamma repeater bursts
Soft gamma repeaters (SGRs) have unique properties that make them intriguing targets for gravitational wave (GW) searches. They are nearby, their burst emission mechanism may involve neutron star crust fractures and excitation of quasinormal modes, and they burst repeatedly and sometimes spectacularly. A recent LIGO search for transient GW from these sources placed upper limits on a set of almost 200 individual SGR bursts. These limits were within the theoretically predicted range of some models. We present a new search strategy which builds upon the method used there by “stacking” potential GW signals from multiple SGR bursts. We assume that variation in the time difference between burst electromagnetic emission and burst GW emission is small relative to the GW signal duration, and we time-align GW excess power time-frequency tilings containing individual burst triggers to their corresponding electromagnetic emissions. Using Monte Carlo simulations, we confirm that gains in GW energy sensitivity of N^(1/2) are possible, where N is the number of stacked SGR bursts. Estimated sensitivities for a mock search for gravitational waves from the 2006 March 29 storm from SGR 1900+14 are also presented, for two GW emission models, “fluence-weighted” and “flat” (unweighted).
14181827
Search method for unmodeled transient gravitational waves associated with SGR flares
We describe a method for searching for transient gravitational waves associated with soft gamma-ray repeater (SGR) flares or other burst-like events using data collected by interferometric gravitational wave detectors. The method can be used to analyze data from either a single detector or from two detectors coherently. The excess power-type algorithm creates event sets from conditioned detector data which may be compared to signal simulations of known strength based on plausible waveform classes. Estimated search sensitivities obtained by performing two-detector searches on the simulated data are presented. In the case of 22 ms duration white noise bursts in the 100–200 Hz band injected into simulated noise, we find a characteristic strain sensitivity h90%rss = 3.0 × 10−22 .
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.
3138911
Accurate measurement of the time delay in the response of the LIGO gravitational wave detectors
We present a method to precisely calibrate the time delay in a long baseline gravitational-wave interferometer. An accurate time stamp is crucial for data analysis of gravitational wave detectors, especially when performing coincidence and correlation analyses between multiple detectors. Our method uses an intensity-modulated radiation pressure force to actuate on the mirrors. The time delay is measured by comparing the phase of the signal at the actuation point with the phase of the recorded signal within the calibrated data stream used for gravitational wave searches. Because the signal-injection path is independent of the interferometer's control system, which is used for the standard calibration, this method can be an independent verification of the timing error in the system. A measurement performed with the 4 km interferometer at the LIGO Hanford Observatory shows a 1 µs relative accuracy when averaging over 50 min. Our understanding of the systematic time delay in the detector response has reached the level of 10 µs.