The ~1S_0 neutron-neutron (nn) scattering length's currently accepted value (a_(nn) chemical bounds -18.6 +-0.3 fm) is derived exclusively from two pi ~--d capture-reaction experiments, in disagreement with the vaerage-16.7+0.5 fm extracted from kinematically-complete nd breakup experiments. This discrepancy may be due to deficiencies in the the analyses of n-d breakup data and/or three-nueleon force (3NF) effects. a kinematically-complete n+d->n_1+n_2+p breakup experiment at an incidnet entron energy of 13.0 MeV was performed recently at TUNL. The value of a_(nn) was extracted from the direct comparison of experimental and rigorously-calculated theoretical nd breakup differential cross sections at four production angles of the nn pair. Using modern nucleon-nucleon potential models in the three-nucleon cross-section calculations we obtained a_(nn) chemical bounds 18.7 +-0.6 fm, in agreement w ith the pi ~--d result. We found no significnant effect due to 3NFs on our a_(nn) value.
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