Transverse phase space and its multipole decomposition
  Relativistic phase space distributions are very interesting objects as they allow one to gather the information extracted from various types of experiments into a single coherent picture. Focusing on the four-dimensional transverse phase space, we identified all the possible angular correlations providing at the same time a clear physical interpretation of all the leading-twist generalized and transverse-momentum dependent parton distributions. We also developed a convenient representation of this four-dimensional space. 
C\'edric Lorc\'e (Ecole polytechnique, CPHT) and Barbara Pasquini   (INFN, Pavia & Pavia U.)
hep-ph nucl-th