Probing the Standard Model through radiative corrections

I report about the computation of quantum corrections to Standard Model observables, in particular the QCD corrections to Flavor Changing Neutral Currents decays of the b-quark, which are found to enhance very significantly the lowest order branching ratios of rare processes, like the b->s gamma decay; and the weak two-loop radiative corrections to LEP observables, particularly the rho parameter and the Z-> b bbar, in the limit of dominance of heavy top and Higgs exchanges. The inclusive B.R of the b->s gamma decay has been later measured by the CLEO collaboration, and the QCD corrections have been found crucial for the agreement with the theoretical predictions. The two-loop heavy top effects have been found instead to be less dramatic, and contributed to the confidence that quantum corrections to LEP observables are well under control

Gravitational wave astronomy

We are entering a new era of gravitational-wave astronomy. The ground-based interferometers have reached their initial design sensitivity in the audio band. Several upper limits have been set for anticipated astrophysical sources from the science data. The advanced detectors in the US and in Europe are expected to be operational around 2015. New advanced detectors are also planned in Japan and in India. The first direct detections of gravitational waves are expected within this decade. In the meanwhile, three pulsar timing array projects are forming an international collaboration to detect gravitational waves directly in the nanoHertz range using timing data from millisecond pulsars. The first direct detection of nanoHertz gravitational waves are also expected within this decade. In this paper, we review the status of current gravitational-wave detectors, possible types of sources, observational upper limits achieved, and future prospects for direct detection of gravitational waves

Virgo gravitational wave detector: Results and perspectives

The Virgo detector reached during the past science run a sensitivity very close to the design one. During the last year the detector has been improved by suspending the main interferometer mirrors with monolithic fibers, with the goal of reducing the thermal noise contribution and testing the new technology. At the same time the design of the next detector improvements are on-going and they will be implemented during the construction of Advanced Virgo

A state observer for the Virgo inverted pendulum

International audienceWe report an application of Kalman filtering to the inverted pendulum (IP) of the Virgo gravitational wave interferometer. Using subspace method system identification techniques, we calculated a linear mechanical model of Virgo IP from experimental transfer functions. We then developed a Kalman filter, based on the obtained state space representation, that estimates from open loop time domain data, the state variables of the system. This allows the observation (and eventually control) of every resonance mode of the IP mechanical structure independently

INTRODUCTION TO THE DATA ANALYSIS IN INTERFEROMETRIC GRAVITATIONAL WAVE EXPERIMENTS

A concise introduction to the problems of data analysis for gravitational wave experiment is given. The aim was to offer a broad overview, which could help the newcomer in the field to approach the vast existing literature, while also giving a few computational details so as to keep the treatment self-contained, and appropriate for a Physics School. To this end the several simplifications have been made, trying to stick to the most crucial aspects of physics or methods

ADVANCED GRAVITATIONAL WAVE DETECTORS AND THE GLOBAL NETWORK

A wide range of gravitational wave detectors is currently operating, and in a few years will reach a sensitivity enabling them to potentially detect sources tens of megaparsec away. In the next years, the instruments will be upgraded, giving birth to a new generation of improved, more sensitive detectors. Alternative techniques are also being explored which have the potential in a longer term of even better sensitivities. Such improvements are needed to turn a still elusive hunt for a first detection into a real gravitational-wave astronomy; it is the purpose of this talk to outline the path toward the design and realization of advanced detectors, and to discuss how they will be integrated into a global network

Observational perspectives with advanced gravitational wave detectors

The installation and commissioning of 2nd generation, advanced gravitational wave detectors is progressing on schedule, and observations will start in the second half of 2015, beginning with the two LIGO detectors, whereas Virgo will join in 2016. The instruments will gradually lower their noise floor, eventually achieving a tenfold increase in amplitude sensitivity, which translates for some impulsive sources in a thousandfold increase in event rate. In this talk we will review the main science objectives and expected observational perspectives of the advanced detectors network

Searches for gravitational-wave events in coincidence with γ events

In this paper we report about the status and prospects of the search for gravitational wave events in coincidence with γ-ray burst events in data from LIGO and Virgo detectors