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

Efficiency of different matrix inversion methods applied to Wilson fermions

We compare different conjugate gradient -- like matrix inversion methods (CG, BiCGstab1 and BiCGstab2) employing for this purpose the compact lattice quantum electrodynamics (QED) with Wilson fermions. The main goals of this investigation are the CPU time efficiency of the methods as well as the influence of machine precision on the reliability of (physical) results especially close to the 'critical' line ~\kappa_c(\bt).Comment: 27 pages LaTeX (epsf), all figures include

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

Navigating the Unknown: Barriers to Evidence-Based Defence and Security Policy in the EU

At a time when Europe faces numerous crises, there is a real need for rigorous evidence to underpin effective policymaking. However, a gap between academia and policy creates clear obstacles in the use of evidence in policymaking. Many of these enduring obstacles are manifest in the inherent differences between separate communities: academics have difficulty communicating research in an applicable manner, and policymakers, in turn, tend to focus on operational motivations. The gap widens considerably when foreign, security and defence policy within the complex institutional structures of the European Union is considered. In addition to these well known barriers to evidence-based policy, there are two more obstacles in the defence and security space: sovereignty and dispersed decision-making. A dialogue of best practices must be opened up to broker knowledge in the EU context

From 9/11 to Da\u2019esh: What role for the High Representative in the external dimension of EU counter-terrorism policies?

Under certain conditions, such as security crises, an integrated external EU counter-terrorism policy can emerge without leading to the supra-nationalisation of policy-making. This paper analyses the role of the High Representative for Foreign Affairs and Security Policy with the objective of assessing the influence that such figure can have on the governance of EU counter-terrorism policies. It does so by assessing the EU\u2019s response to three security crises, namely: the 9/11 attacks and the subsequent bombings in Madrid (2004) and London (2005); the Arab Spring and the following destabilisation of the Middle East and North Africa (MENA); and the emergence and spread of Da\u2019esh

LISA test mass charging process due to cosmic ray nuclei and electrons

none10noolar energetic particles and galactic cosmic rays with energies larger than 100 MeV cause progressive charging of the LISA experiment test masses. Consequently, Coulomb forces occur between the test masses and the surrounding conducting surfaces generating spurious signals that might be mistaken for gravitational wave signals. We have parametrized the energy spectra of galactic cosmic-ray nuclei and electrons near the LISA orbit in order to evaluate their role in the test-mass charging relative to the most abundant proton component. This work has been carried out using the FLUKA Monte Carlo program.openC. GRIMANI; H. VOCCA; G. BAGNI; L. MARCONI; R. STANGA; F. VETRANO; A. VICERÉ; P. AMICO; L. GAMMAITONI; F. MARCHESONIGrimani, Catia; H., Vocca; G., Bagni; L., Marconi; R., Stanga; Vetrano, Flavio; Vicere', Andrea; P., Amico; L., Gammaitoni; F., Marcheson

Inertial control of the mirror suspensions of the VIRGO interferometer for gravitational wave detection

In order to achieve full detection sensitivity at low frequencies, the mirrors of interferometric gravitational wave detectors must be isolated from seismic noise. The VIRGO vibration isolator, called 'superattenuator', is fully effective at frequencies above 4 Hz. Nevertheless, the residual motion of the mirror at the mechanical resonant frequencies of the system are too large for the interferometer locking system and must be damped. A multidimensional feedback system, using inertial sensors and digital processing, has been designed for this purpose. An experimental procedure for determining the feedback control of the system has been defined. In this paper a full description of the system is given and experimental results are presented.Comment: 17 pages, 11 figures, accepted for publication on Review of Scientific Instrument

Sensitivity Studies for Third-Generation Gravitational Wave Observatories

Advanced gravitational wave detectors, currently under construction, are expected to directly observe gravitational wave signals of astrophysical origin. The Einstein Telescope, a third-generation gravitational wave detector, has been proposed in order to fully open up the emerging field of gravitational wave astronomy. In this article we describe sensitivity models for the Einstein Telescope and investigate potential limits imposed by fundamental noise sources. A special focus is set on evaluating the frequency band below 10Hz where a complex mixture of seismic, gravity gradient, suspension thermal and radiation pressure noise dominates. We develop the most accurate sensitivity model, referred to as ET-D, for a third-generation detector so far, including the most relevant fundamental noise contributions.Comment: 13 pages, 7 picture