Maio A.,Portuguese Laboratory of Instrumentation and Experimental Particle Physics |
Maio A.,University of Lisbon
Journal of Physics: Conference Series | Year: 2015
The SNO+ experiment is adapting the Sudbury Neutrino Observatory (SNO) detector, in order to use isotope-loaded liquid scintillator as the active medium. SNO+ has multiple scientific goals, the main one being the search for neutrinoless double beta decay, the most promising signature for the possible Majorana character of neutrinos and for the absolute neutrino mass. Measurements of neutrinos from the Sun, the Earth, Supernovae and nuclear reactors are additional goals of the experiment. The detector consists of a 12m diameter spherical vessel, filled with 780 tonnes of Tellurium-loaded liquid scintillator, and surrounded by about 9500 PMTs. It is shielded by a large volume of ultra-pure water and the underground location at SNOLAB, Canada. This talk will review the Physics goals and current status of SNO+. © 2014 Published under licence by IOP Publishing Ltd.
Silva L.,Portuguese Laboratory of Instrumentation and Experimental Particle Physics
Few-Body Systems | Year: 2013
Over the last decade the COMPASS experiment has successfully obtained precise results on nucleon structure and hadron spectroscopy, with statistical errors much lower than previously reported. Recently, the new COMPASS-II program, focused on the study of a more complete nucleon description, was approved by CERN. The goal of the program is to access the nucleon structure beyond the collinear approxi-mation, including the quark intrinsic transverse momentum distributions, which are described by the Transverse Momentum Dependent (TMD) Parton Distribution Functions (PDFs) and by Generalised Parton Distributions (GPDs). The COMPASS collaboration proposes to measure the TMD PDFs, for the first time, via the polarised Drell-Yan process. The results will be complementary to those already obtained in polarised Semi-Inclusive Deep Inelastic Scattering (SIDIS). The GPDs can be accessed using deeply virtual Compton scattering and hard exclusive meson production using an unpolarised hydrogen target in a kinematic region not yet covered by any existing experiment. Also unpolarised SIDIS will be studied, by improving the knowledge of the strange quark PDF and obtaining the kaon fragmentation functions. Another topic covered in this COMPASS-II program is the measurement of the pion and kaon polarisabilities using the Primakoff reaction, which corresponds to a test of the chiral perturbative theory. © 2013 Springer-Verlag Wien.
Quaresma M.,Portuguese Laboratory of Instrumentation and Experimental Particle Physics
Acta Physica Polonica B, Proceedings Supplement | Year: 2012
The Parton Distribution Functions (PDFs) and the spin structure of the nucleon are important topics studied by the COMPASS experiment. The Drell-Yan (DY) process will be used in the future COMPASS-II measurements to access the Transverse Momentum Dependent PDFs (TMD PDFs). Studying the angular distributions of dimuons from the DY reactions with a negative pion beam with 190 GeV/c momentum and a transversely polarised proton target, we will be able to extract the azimuthal spin asymmetries and to access the various TMD PDFs, such as Sivers and Boer-Mulders functions. The start of the COMPASS DY experiment is scheduled for 2014. Three beam tests have been already performed, one of them in 2009 using a prototype hadron absorber downstream of the target, to understand the background reduction factors and the spectrometer response, and also to verify our results from Monte Carlo simulations. COMPASS aims at performing the first DY experiment with a transversely polarised target.
Quintans C.,Portuguese Laboratory of Instrumentation and Experimental Particle Physics
Journal of Physics: Conference Series | Year: 2011
The COMPASS experiment at CERN studies the spin structure of the nucleon, using its unique polarized target in both longitudinal and transverse polarization modes. The future Drell-Yan measurement by the COMPASS collaboration proposes to access the transverse momentum dependent parton distribution functions, namely Sivers and Boer-Mulders functions. The Drell-Yan process with unpolarized and with transversely polarized target is a very promising tool for this purpose, complementary to the semi-inclusive deep inelastic scattering measurements available from COMPASS, HERMES and JLab experiments. Also interesting related studies like the J/ψ-Drell-Yan duality are proposed. The physics case, as well as the most important technical aspects of this project are presented.
Seabra L.,Portuguese Laboratory of Instrumentation and Experimental Particle Physics
Proceedings of the IEEE International Conference on Industrial Technology | Year: 2015
ALFA (Absolute Luminosity For ATLAS) is one of the sub-detectors of ATLAS (A Toroidal LHC Apparatus). The ALFA system is composed by four stations installed in the LHC tunnel 240 m away from the ATLAS interaction point. Each station has a vacuum and ventilation system, movement control and all the required electronics for signal processing. The Detector Control System (DCS) provides control and monitoring of several components and ensures the safe operation of the detector contributing to good Data Quality. This paper describes the ALFA DCS system including a detector overview, operation aspects and hardware control through a SCADA system, WinCC OA. © 2015 IEEE.