Speaker
Description
We discuss recent extraction of parton distribution function of pion in the valence region which observed
unexpectedly soft $(1-x)^\beta$, $\beta\sim 1$ distribution, contradicting several theoretical predictions including the ones
based on the hard gluon exchange, according to which $\beta =2$.
In this work we calculated the pion PDF within the theoretical approach based on spectral function representation
of valence structure in the nucleon.
The approach was first applied for nucleon valence PDF’s which demonstrated the existence of pion-cloud structure
in the nucleon already at the starting $Q_0$ for which initial PDF’s are defined. Our calculation also shows substantial high momentum
component in nucleon for large x. Applying the same approach for calculation of pion valence PDF’s, we first observe that
no additional residual structure exists in the pion as it was the case for nucleons. Our calculation largely describes the recently obtained
phenomenological PDF’s by JAM collaboration. We observe that the Feynman mechanism is responsible for pion PDF at
relatively large x leaving little room for the hard q\bar q interaction at the large x region.
