Speaker
Description
We present an extraction for the unpolarised transverse momentum dependent (TMD) parton distribution functions (PDFs) for the quarks in the pion from measurements of the Drell-Yan process.
The results are obtained from a fit of the non-perturbative part of the TMDPDFs in the framework of TMD factorisation
and rely on the non-perturbative input for the collinear PDFs.
As the data is limited, affected by a large normalisation uncertainty
and covers only a region of relatively large momentum fractions ( $x > 0.18$ ),
the phenomenological extraction is at a disadvantage.
We illustrate the precise impacts of these drawbacks to make clear up to which extent such an extraction can be reliable in the first place.
Additionally such an extraction relies on several choices, which we explain and motivate those we make.
We obtain a good agreement with data in a qualitative and quantitative way
and as a result of our analysis strategy we do not observe a large normalisation issue between data and theory.
We highlight the developments from lattice (LaMET) which can eventually help to compliment the information we have from the experiments.
We also stress what the measurements from COMPASS can pragmatically improve in such kind of extractions.