  Nuclear halos are very exotic quantal structures observed far from stability.
Because of their short lifetime, they are mostly studied through reactions. The
ratio method offers a new observable: the ratio of angular differential cross
sections for breakup and scattering. It is predicted to be much more sensitive
to the projectile structure than individual cross sections thanks to its
independence of the reaction process. We test this new observable
experimentally for the first time considering the collision of 11Be on C at
22.8 MeV/nucleon. We extend this analysis to similar data recently measured on
Pb at 19.1 MeV/nucleon. Both analyses confirm the theoretical predictions,
which opens the door to a new era in the study of nuclear structure near the
neutron dripline. This should prove invaluable in conjunction with the start of
FRIB. The ratio method could also be extended to other fields of quantum
physics beyond nuclear reactions.
