  We extend our previous calculation of the breakup of 11Be using Halo
Effective Field Theory and the Dynamical Eikonal Approximation to include an
effective 10Be-n-target force. The force is constructed to account for the
virtual excitation of 10Be to its low-lying 2+ excited state. In the case of
breakup on a 12C target this improves the description of the neutron-energy and
angular spectra, especially in the vicinity of the 11Be 5/2+ state. By
fine-tuning the range parameters of the three-body force, a reasonable
description of data in the region of the 3/2+ 11Be state can also be obtained.
This sensitivity to the three-body force's range results from the structure of
the overlap integral that governs the 11Be s-to-d-state transitions induced by
the three-body force.
