Transverse phase space and its multipole decomposition

Abstract

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.

Studying the information content of TMDs using Monte Carlo generators

“…It is the only model so far including sea quarks, and predicts that sea-quark TMDs have significantly broader k T -distributions than valence quarks, due to nonperturbative short-distance correlations caused by chiral symmetry breaking effects [66]. All T-even TMDs were predicted within the light-front version of this model restricted to the 3-quark light-front Fock state [67].…”

“…The modeling of T-odd TMDs requires explicit gauge-field degrees of freedom, while for T-even TMDs it is sufficient to consider quark degrees of freedom. Models of T-even TMDs can be classified as follows: (a) spectator models [56][57][58][59][60][61]; (b) light-front models [29,[62][63][64]; (c) chiral quark soliton models [65][66][67]; (d) bag models [68,69]; (e) covariant parton models [70][71][72]; (f) quark-target models [73][74][75][76][77].…”

“…It has been applied to calculate all twist-2 and twist-3 T-even TMDs in [68,69], and a complete set of linear and non-linear relations among them was derived (see also Ref. [88] for a discussion of the validity of such relations in quark models). Another remarkable insight is that the bag model strongly supports the Gaussian k Tdependence of TMDs observed in phenomenology [89].…”