W physics at LEP

Studying the properties of the W boson plays a key role in precision tests of the Standard Model. The key measurements performed over the last decade will be reviewed. W-pair and single-W cross-sections and W decay branching fractions are determined and agree well with theoretical predictions. Including the analysis of differential distributions, trilinear and quartic couplings of the W boson to the other gauge bosons are extracted. A precise measurement of the mass and width of the W boson is presented. The W mass is in good agreement with the one obtained indirectly from an analysis of other electroweak data measured at LEP and SLD. Some of the results presented in this article are preliminary.Comment: Invited talk at the XXIII Physics in Collisions Conference (PIC03), Zeuthen, Germany, June 2003, 11 page

Nanostructured target fabrication with metal and semiconductor nanoparticles

The development of ultra-intense high-energy (≫1 J) short (<1 ps) laser pulses in the last decade hasenabled the acceleration of high-energy short-pulse proton beams. A key parameter for enhancing theacceleration regime is the laser-to-target absorption, which heavily depends on the target structureand material. In this work, we present the realization of a nanostructured target with a sub-laserwavelength nano-layer in the front surface as a possible candidate for improving the absorption. Thenanostructuredfilm was realized by a simpler and cheaper method than using conventionallithographic techniques: A colloidal solution of metallic or semiconductor nanoparticles (NPs) wasproduced by laser ablation and, after a heating and sonication process, was spray-dried on the frontsurface of an aluminum target. The obtained nanostructuredfilm with a thickness of 1μm appears, atmorphological and chemical analysis, uniformly nanostructured and distributed on the target surfacewithout the presence of oxides or external contaminants. Finally, the size of the NPs can be tuned fromtens to hundreds of nanometers simply by varying the growth parameters (i.e., irradiation time,fluence, and laser beam energy

Laser-Plasma driven synthesis of carbon-based nanomaterials

In this paper we introduce a laser-plasma driven method for the production of carbon based nanomaterials and in particular bi- and few-layers of Graphene. This is obtained by using laser-plasma exfoliation of amorphous Graphite in a liquid solution, employing a laser with energy in the order of 0.5 J/mm2. Raman and XPS analysis of a carbon colloidal performed at different irradiation stages indicate the formation of Graphene multilayers with an increasing number of layers: the amount of layers varies from a monolayer obtained in the first few seconds of the laser irradiation, up to two layers obtained after 10 s, and finally to Graphite and amorphous carbon obtained after 40 s of irradiation. The obtained colloidals are pure, without any presence of impurities or Graphene oxides, and can easily be deposited onto large surfaces (in the order of cm2) for being characterized or for being used in diverse applications

In situ study of nucleation and aggregation phases for nanoparticles grown by laser-driven methods

In the last decades, nanomaterials and nanotechnologies have become fundamental and irreplaceable in many fields of science and technology. When used in applications, their properties depend on many factors such as size, shape, internal structure and composition. For this, exact knowledge of their structural features is essential when developing fabrication technologies and searching for new types of nanostructures or nanoparticles with specific properties. For the latter, the knowledge of the precise temporal evolution of the growth processes is fundamental when it comes to industrial production and applications. Here we present a method to control, with very high precision, the starting of the aggregation phase during the Laser Ablation in solution growth process. This is obtained by monitoring the optical absorption of the colloidal solution. We apply this control method on the most popular metallic nanoparticle materials (Ag, Al, Co, and Ti) and verify the technique using morphological analysis conducted by AFM and SEM microscopy. The experimental results are explained in terms of Mie extinction theory and Thermal Model for Laser Ablatio

Present Status of experimental determination of Vcb

The present status of our knowledge of the magnitude of the quark mixing parameter Vcb is reviewed, with particular emphasis on the factors affecting experimental and theoretical errors and on prospects for a more precise determination.Comment: 15 pages and 3 figures, an abbreviated version is included in PDG2002 as a mini-review on Vc

MC-TESTER: a universal tool for comparisons of Monte Carlo predictions for particle decays in high energy physics

Theoretical predictions in high energy physics are routinely provided in the form of Monte Carlo generators. Comparisons of predictions from different programs and/or different initialization set-ups are often necessary. MC-TESTER can be used for such tests of decays of intermediate states (particles or resonances) in a semi-automated way. Our test consists of two steps. Different Monte Carlo programs are run; events with decays of a chosen particle are searched, decay trees are analysed and appropriate information is stored. Then, at the analysis step, a list of all found decay modes is defined and branching ratios are calculated for both runs. Histograms of all scalar Lorentz-invariant masses constructed from the decay products are plotted and compared for each decay mode found in both runs. For each plot a measure of the difference of the distributions is calculated and its maximal value over all histograms for each decay channel is printed in a summary table. As an example of MC-TESTER application, we include a test with the tau lepton decay Monte Carlo generators, TAUOLA and PYTHIA. The HEPEVT (or LUJETS) common block is used as exclusive source of information on the generated events.Comment: Version as published in Computer Physics Communications, 157(2004) 1, pp 39-6

B Meson Decays

We discuss the most important Physics thus far extracted from studies of B meson decays. Measurements of the four CP violating angles accessible in B decay are reviewed as well as direct CP violation. A detailed discussion of the measurements of the CKM elements V_{cb} and V_{ub} from semileptonic decays is given, and the differences between resulting values using inclusive decays versus exclusive decays is discussed. Measurements of "rare" decays are also reviewed. We point out where CP violating and rare decays could lead to observations of physics beyond that of the Standard Model in future experiments. If such physics is found by directly observation of new particles, e.g. in LHC experiments, B decays can play a decisive role in interpreting the nature of these particles.Comment: 80 pages, 29 figures, invited review article for PMC Physics A; version 2 a few minor corrections, version 3 fixed some references, version 4 two minor fixe

Inelastic Dark Matter and the SABRE Experiment

We present here the sensitivity of the SABRE (Sodium iodide with Active Background REjection) experiment to benchmark proto-philic, spin dependent, Inelastic Dark Matter models previously proposed due to their lowered tension with existing experimental results. We perform fits to cross section, mass, and mass splitting values to find the best fit to DAMA/LIBRA data for these models. In this analysis, we consider the Standard Halo Model (SHM), as well as an interesting extension upon it, the SHM+Stream distribution, to investigate the influence of the Dark Matter velocity distribution upon experimental sensitivity and whether or not its consideration may be able to help relieve the present experimental tension. Based on our analysis, SABRE should be sensitive to all the three benchmark models within 3-5 years of data taking.Comment: Adjusted for full DAMA run 1+2 efficiency. Updated to match published versio

Laser-Accelerated proton beams as diagnostics for cultural heritage

This paper introduces the first use of laser-generated proton beams as diagnostic for materials of interest in the domain of Cultural Heritage. Using laser-accelerated protons, as generated by interaction of a high-power short-pulse laser with a solid target, we can produce proton-induced X-ray emission spectroscopies (PIXE). By correctly tuning the proton flux on the sample, we are able to perform the PIXE in a single shot without provoking more damage to the sample than conventional methodologies. We verify this by experimentally irradiating materials of interest in the Cultural Heritage with laser-accelerated protons and measuring the PIXE emission. The morphological and chemical analysis of the sample before and after irradiation are compared in order to assess the damage provoked to the artifact. Montecarlo simulations confirm that the temperature in the sample stays safely below the melting point. Compared to conventional diagnostic methodologies, laser-driven PIXE has the advantage of being potentially quicker and more efficien

The use of social media in EU policy communication and implications for the emergence of a European public sphere

Cohesion policy is the European Union’s (EU) main investment policy and seeks to strengthen economic, social and territorial cohesion. While accomplishments in this regard are constantly measured, European citizens are not always aware of the policy’s impact and the role the EU plays therein. This is especially relevant as the communication of EU policies is central to the emergence of a European public sphere, an acknowledged condition for European integration. In this paper, we aim at advancing research in this regard through the analysis of cohesion policy communication on the social media channels of ten Local Managing Authorities (LMAs) responsible for managing and communicating structural funds at the local level. By building on a bottom-up construction of shared meaning structures through semi-automatic analysis techniques, we make the following three observations: first, social media communication is indicative of "horizontal Europeanization"; second, Europeanization occurs both in the form of the spontaneous amalgamation of shared discontent expressed by citizens and the institutionalization of top-down EU communication measures adopted by LMAs; and third, a cluster of topics articulated internationally and showcasing a negative attitude towards the EU funding scheme suggests that, counter-intuitively, Euroscepticism seems to facilitate the emergence of a European public sphere