Measurement of Delta G/G from high transverse momentum hadron pairs in COMPASS

The new COMPASS Delta G/G result obtained from high transverse momentum hadron pairs in the Q^2>1 GeV^2 region is presented. Comparing to the previous analysis in this region the statistical error of Delta G/G is reduced by a factor 3 to 0.10. A weighted method of the Delta G/G measurement based on neural network approach is used. In addition, the formula for the Delta G/G extraction used in the analysis has been updated. The contributions coming from the leading order and QCD Compton processes are no longer neglected.Comment: On behalf of COMPASS Collaboration, DIS08 proc, 4 page

New COMPASS results on polarised parton distributions inside nucleon

Peer Reviewe

Final COMPASS results on hadrons, pions and kaons multiplicities in SIDIS

COMPASS final results on multiplicities of charged hadrons and of identified pions and kaons produced in the deep inelastic muon scattering off an isoscalar target are presented. Measurements are done in bins of x,y and z in a wide kinematic range. The hadron and pion data show a good agreement with (N)LO QCD expectations. The most interesting is the kaon multiplicity that allows to extract kaon fragmentation functions, a crucial ingredient in solving the strange quark polarisation puzzle. The COMPASS results are quite different from the expectations of the old NLO DSS fit; and they cannot be described by LO QCD either. In this context the importance of $K^+ / K^-$ multiplicity ratio at high z is discussed.Peer Reviewe

Building distributed ground station system with radio amateurs, Journal of Telecommunications and Information Technology, 2007, nr 1

The paper concerns radio amateur satellites that are built by international student teams. For contacting a satellite, a single ground station is usually used. In this configuration and with the satellite on the low Earth orbit (LEO), teams have contact only for about 40 minutes per day. If the satellite has service for radio amateurs, they use it for 20 hours per day. A lot of them have connection to Internet. This is a big difference. In this paper, is shown how they can use the radio amateur transceivers and antenna systems in order to build ground stations network named distributed ground station system (DGSS). Frequencies, types of modulations, calculation of power budge, and the ways to control amateur stations by the Internet are also shown. These are essential procedures, because radio amateurs have their standards and habits. Finally a proposal of implementation dedicated DGSS system for radio amateurs with and without use of APRS network is put forward. Distributed ground station is one of the experiments on PW-Sat satellite, which is being build on the Warsaw University of Technology

Collins and Sivers asymmetries in muonproduction of pions and kaons off transversely polarised protons

Measurements of the Collins and Sivers asymmetries for charged pions and charged and neutral kaons produced in semi-inclusive deep-inelastic scattering of high energy muons off transversely polarised protons are presented. The results were obtained using all the available COMPASS proton data, which were taken in the years 2007 and 2010. The Collins asymmetries exhibit in the valence region a non-zero signal for pions and there are hints of non-zero signal also for kaons. The Sivers asymmetries are found to be positive for positive pions and kaons and compatible with zero otherwise. © 2015

COMPASS spin dependent longitudinal asymmetries on deuteron target

Abstrac

Spin physics - longitudinal

A short review of the COMPASS results obtained in polarized deep inelastic scattering of polarized muons off longitudinally polarized proton and deuteron targets is given. Two new measurements of the gluon polarization $\Delta G / G$ are discussed. A new LO result from the analysis of high-$p_{T}$ hadron pairs for $Q^{2}$ > 1 (GeV/c)$^{2}$ and separated into three experimental points as a function of $x_{G}$ is shown. A new open charm value for $\Delta G / G$ obtained at NLO, and which combines both proton and deuteron data and includes several $D^{0}$ decay channels is presented. Finally results for the LO flavor separation of the three lightest quark polarized parton distributions and charged $\pi$ and K multiplicities are shown