Laser-Generated Proton Beams for High-Precision Ultra-Fast Crystal Synthesis

We present a method for the synthesis of micro-crystals and micro-structured surfaces using laseraccelerated protons. In this method, a solid surface material having a low melting temperature is irradiated with very-short laser-generated protons, provoking in the ablation process thermodynamic conditions that are between the boiling and the critical point. The intense and very quick proton energy deposition (in the ns range) induces an explosive boiling and produces microcrystals that nucleate in a plasma plume composed by ions and atoms detached from the laser-irradiated surface. The synthesized particles in the plasma plume are then deposited onto a cold neighboring, non-irradiated, solid secondary surface. We experimentally verify the synthesizing methods by depositing low-meltingmaterial microcrystals - such as gold - onto nearby silver surfaces and modeling the proton/matter interaction via a Monte Carlo code, confrming that we are in the above described thermodynamic conditions. Morphological and crystallinity measurements indicate the formation of gold octahedral crystals with dimensions around 1.2 μm, uniformly distributed onto a silver surface with dimensions in the tens of mm2. This laser-accelerated particle based synthesis method paves the way for the development of new material synthesis using ultrashort laser-accelerated particle beams

CP asymmetries at D0

Using two independent measurements of the semileptonic CP asymmetry in the $B_s$ system, we constrain the CP violating phase of the $B_s$ system to be $\phi_s = -0.70^{+0.47}_{-0.39}$. The data sample corresponds to an integrated luminosity of 1.1 fb$^{-1}$ accumulated with D0 detector at the Fermilab Tevatron collider. We also measure the direct CP violating asymmetry in the decay $B^+ \to J/\psi K^+$ to be $A_{CP}(B^+ \to J/\psi K^+) = +0.0067 \pm 0.0074$(stat)$\pm0.0026$(syst). The data corresponds to an integrated luminosity of 1.6 fb$^{-1}$.Comment: contributed paper to EPS07, Manchester, UK, manuscript number EPSHEPP17

COXIELLA BURNETII INFECTION IN DAIRY COWS AND GOATS: ASSESSMENT OF DIAGNOSTIC METHODS, AND EVALUATION OF IMMUNE RESPONSE IN SHEDDERS

Q fever is an infective, contagious and zoonotic disease caused by Coxiella burnetii, an obligate intracellular bacterium. The first goal of this research was to assess the efficacy of a diagnostic strategy based on real-time PCR (r-t PCR) assays on bulk tank milk (BTM) for the detection of infected dairy herds/flocks, with the aim of estimating the prevalence of Q fever infection in dairy herds and in goats flocks. The second goal was to evaluate the dynamics of the antibodies response and the C. burnetii excretion in infected animals. The sensitivity and specificity of a single r-t PCR test on BTM were evaluated using a control-case study in dairy herds and goat flocks. To study the C. burnetii transmission in dairy herds and goats flocks a longitudinal study was performed. The sensitivity and specificity of BTM r-t PCR in dairy herds were respectively equal to 0.5 and 1, and in dairy flocks 0.8 and 1. The results highlighted in dairy cows a great gap between the seroprevalence and the percentage of shedders found in the herds. The seroprevalence was on average 30,6%, while the percentage of shedders was at least 13% and the percentage of strong shedders was only 1,7%. We observed also the presence of 14 cows shedding C. burnetii in milk without an appreciable serological response. Shedding in feces was sporadic and only 9 cows were found to shed the bacterium occasionally through this route. The goats sampled were 257, coming from 3 flocks very different in size, ranging from 12 to 171 goats. The shedders of C. burnetii in milk were 59 (23%), the ELISA seropositive goats 177 (69%), the CFT seropositive goats 11 (4%). The percentage of shedders in milk was very different among the flocks, ranging from 100% of farm 2 to 1% of farm 3. Shedding of C. burnetii in stools was detected only occasionally in flocks 2 and 3, while in flock 1 at 2nd sampling 15 positives goats were detected. The great majority of ELISA seropositive goats kept this status throughout the study time

Fast shower simulation in the ATLAS calorimeter

The time to simulate pp collisions in the ATLAS detector is largely dominated by the showering of electromagnetic particles in the heavy parts of the detector, especially the electromagnetic barrel and endcap calorimeters. Two procedures have been developed to accelerate the processing time of electromagnetic particles in these regions: (1) a fast shower parameterisation and (2) a frozen shower library. Both work by generating the response of the calorimeter to electrons and positrons with Geant 4, and then reintroduce the response into the simulation at runtime. In the fast shower parameterisation technique, a parameterisation is tuned to single electrons and used later by simulation. In the frozen shower technique, actual showers from low-energy particles are used in the simulation. Full Geant 4 simulation is used to develop showers down to ~1 GeV, at which point the shower is terminated by substituting a frozen shower. Judicious use of both techniques over the entire electromagnetic portion of the ATLAS calorimeter produces an important improvement of CPU time. We discuss the algorithms and their performance in this paper

Recent developments in radiative B decays

We report on recent theoretical progress in radiative B decays. We focus on a calculation of logarithmically enhanced QED corrections to the branching ratio and forward-backward asymmetry in the inclusive rare decay anti-B --> X(s) l+ l-, and present the results of a detailed phenomenological analysis. We also report on the calculation of NNLO QCD corrections to the inclusive decay anti-B --> X(s) gamma. As far as exclusive modes are concerned we consider transversity amplitudes and the impact of right-handed currents in the exclusive anti-B --> K^* l+ l- decay. Finally, we state results for exclusive B --> V gamma decays, notably the time-dependent CP-asymmetry in the exclusive B --> K^* gamma decay and its potential to serve as a so-called ``null test'' of the Standard Model, and the extraction of CKM and unitarity triangle parameters from B --> (rho,omega) gamma and B --> K^* gamma decays.Comment: 5 pages, 2 figures. Accepted for publication in the proceedings of International Europhysics Conference on High Energy Physics (EPS-HEP2007), Manchester, England, 19-25 Jul 200