This experimental research concerns internal structure of the nucleon, includng its spin-dependent degrees of freedom. It will be performed in experiment of the COMPASS Collaboration at CERN using deep inelastic scattering (DIS) of polarized muons on polarized nucleon targets. We propose two subjects:

1. Study of asymmetries of the spin-dependent cross sections, without usually done assumption of independence of DIS itself and the hadronization of quarks. In the limit of very high energy transfers from the virtual photon to the quark, hadronization energy can be neglected and these two processes can be considered independent of each other. However, if energy scales mix, DIS and hadronic variables do not factorize and the process depends on functions accounting for both the nucleon structure and quark fragmentation. This approach opens interesting possibilities for studying structure of different hadrons and QCD evolution of functions more general than the structure- and fragmentation funtions.

2. COMPASS experiment is going to be upgraded with a new detector for registering recoil protons. This enables investigation of the Generalized Parton Distributions. From these distributions, using Jaffe-Ji sum rule, one can determine orbital angular momentum of nucleon constituents: quarks and gluons. This measurements will complete large experimental programme of separate measurement of angular momentum of all internal degrees of freedom of the nucleon. Successful candidate will take part in the preparation of the experiment and analysis of its first data.

Data processing and analysis will be done on the computing Grid. Access to the high-performance top modern infrastructure and training and consultancy for its usage are guaranteed (see Webpage).

More information:
Assoc. Professor Wojciech Wislicki
The Andrzej Soltan Institute for Nuclear Studies
High Energy Physics Department
69 Hoża st.
Warszawa, Poland
phone ++(4822) 5532164
Wojtek.Wislicki@fuw.edu.pl