  We demonstrate that partonic correlations that would traditionally be
identified as subleading on the basis of a generalized TMD-factorization
conjecture can become leading-power because of TMD-factorization breaking that
arises in hadron-hadron collisions with large transverse momentum back-to-back
hadrons produced in the final state. General forms of TMD-factorization fail
for such processes because of a previously noted incompatibility between the
requirements for TMD-factorization and the Ward identities of non-Abelian gauge
theories. We first review the basic steps for factorizing the gluon
distribution and then show that a conflict between TMD-factorization and the
non-Abelian Ward identity arises already at the level of a single extra soft or
collinear gluon when the partonic subprocess involves a TMD gluon distribution.
Next we show that the resulting TMD-factorization violating effects produce
leading-power final state spin asymmetries that would be classified as
subleading in a generalized TMD-factorization framework. We argue that similar
extra TMD-factorization breaking effects may be necessary to explain a range of
open phenomenological QCD puzzles. The potential to observe extra transverse
spin or azimuthal asymmetries in future experiments is highlighted as their
discovery may indicate an influence from novel and unexpected large distance
parton correlations.

High Energy Physics - Phenomenology;High Energy Physics - Experiment;Nuclear Experiment