Measurement of J/psi production at the LHC with the ALICE experiment

ALICE (A Large Ion Collider Experiment) aims at studying the behaviour of nuclear matter at high energy densities and the transition to the Quark Gluon Plasma (QGP), expected to occur in ultra-relativistic heavy ion collisions. Quarkonia production measurements in both Pb-Pb and pp collisions play a crucial role in the ALICE physics program. Quarkonium detection is possible in ALICE at both forward (in the dimuon channel) and mid-rapidity (in the dielectron channel). In 2010, the Large Hadron Collider has provided pp collisions at sqrt(s)=7 TeV and Pb-Pb collisions at sqrt(sNN)=2.76 TeV. The ALICE results on J/psi production in pp collisions are presented, along with the status of the Pb-Pb analysis.Comment: 4 pages, 5 figures; XIX International Workshop on Deep-Inelastic Scattering and Related Subjects (DIS 2011) April 11-15, 2011 Newport News, VA USA; submitted to AIP Proceeding

Noncoherent detection of periodic signals

The optimal Bayes detector for a general periodic waveform having uniform delay and additive white Gaussian noise is examined. It is shown that the detector is much more complex than that for the well known cases of pure sine waves (i.e. classical noncoherent detection) and narrowband signals. An interpretation of the optimal processing is presented, and several implementations are discussed. The results have application to the noncoherent detection of optical square waves

The study of synchronization techniques for optical communication systems Quarterly report, 1 Dec. 1968 - 1 Mar. 1969

Synchronization techniques for optical communication systems, including heterodyne detection, pulsed lasers, and PPM system

Optical synchronization-phase locking with shot noise processes Interim technical report

Optical communication synchronization with phase lock tracking loop and analysis of shot noise processe

The design of a Pulse Position Modulated /PPM/ optical communication system

Design of pulse position modulation optical communication syste

Computing Matveev's complexity via crystallization theory: the boundary case

The notion of Gem-Matveev complexity has been introduced within crystallization theory, as a combinatorial method to estimate Matveev's complexity of closed 3-manifolds; it yielded upper bounds for interesting classes of such manifolds. In this paper we extend the definition to the case of non-empty boundary and prove that for each compact irreducible and boundary-irreducible 3-manifold it coincides with the modified Heegaard complexity introduced by Cattabriga, Mulazzani and Vesnin. Moreover, via Gem-Matveev complexity, we obtain an estimation of Matveev's complexity for all Seifert 3-manifolds with base $\mathbb D^2$ and two exceptional fibers and, therefore, for all torus knot complements.Comment: 27 pages, 14 figure

Overview of ALICE results

The ALICE experiment at the CERN LHC studies the hot and dense medium formed in ultra-relativistic heavy-ion collisions, and the transition to Quark Gluon Plasma. Several observables are used to characterise the medium. In this contribution we report on the main ALICE results on global properties, particle spectra, anisotropies, heavy flavour and quarkonium production, obtained in Pb-Pb collisions at √srmNN = 2.76TeV. Measurements performed in p-Pb and pp collisions are also part of the ALICE physics program: selected highlights from such measurements are discussed

PPM demodulation for Reed-Solomon decoding for the optical space channel

The use of Reed-Solomon (RS) block codes over the pulse position modulated (PPM) frames to obtain the largest degree of error correction is considered. Since RS codes can correct both symbol errors and symbol erasures, a question arises as to the best way to demodulate the PPM laser fields in order to generate the input symbols for the RS decoder. The method selected for demodulating (converting the received laser field to digital symbols) defines the erasure and transmitted symbols of the laser link, and therefore determines the work error probabilities of the system. Several demodulating schemes are considered, and the effect of each on RS decoding performance computed. This computation was carried out for various optical receiver models. It is shown that simple threshold decisioning of pulse slots produces performance that degrades as the background noise increases. This is caused by the generation of too many erasures for the RS decoder to handle. A decision scheme, delta-max demodulation which offers improvement over threshold decisioning by redefining the generation of an erasure is proposed

Heavy flavour and quarkonium production with ALICE at the LHC

Heavy flavour and quarkonia are important probes of the hot and dense QCD medium formed in high energy heavy-ion collisions, through the modification of their yields and kinematical distributions. Moreover, quarkonium production in ultra-peripheral heavy ion collisions is a powerful tool to study the gluon distribution in the nuclei at low Bjorken-x. Quarkonia and heavy flavour production is measured in ALICE at both forward and mid-rapidity, by exploiting several experimental techniques. The main results obtained in Pb-Pb and pp collisions are presented