The nuclear force that binds nucleons together is predominantly scalar, i.e., spin and isospin
independent. The tensor, spin-isospin, and other components, are
much weaker than the main scalar part. Since at typical nucleon distances in nuclei the scalar force is attractive, but becomes repulsive at shorter distances, it must vanish in
between, and there the tensor force become important. The tensor force prefer the spins of the
nucleons to be aligned (deuteron like configurations). Study of Short Range Correlated (SRC)
nucleon pairs is a powerful way to investigate the short range tensor force and the even shorter range illusive
repulsive force. Recent exclusive studies of SRC demonstrated that the single nucleon high - momentum distribution is not sensitive to nuclear structure and exhibits a universal
scaling. The independence on the nuclear size enables the
use of light nuclei for which experimental results can be compared to theoretical predictions.
Data from a recent exclusive measurement on 4He in Hall A, and from the data mining project of Hall B (CLAS), both in Jefferson Laboratory, VA, USA, is shown and discussed.