We present the status of current US experimental efforts to measure the lifetime of the free neutron by the "beam" and "bottle" methods. BBN nucleosynthesis models require accurate measurements with 1 second uncertainties, which are currently feasible. For tests of physics beyond the standard model, future efforts will need to achieve uncertainties well below 1 second. We outline paths achieve both.
@article{arxiv.1410.5311,
title = {Determination of the Free Neutron Lifetime},
author = {J. David Bowman and L. J. Broussard and S. M. Clayton and M. S. Dewey and N. Fomin and K. B. Grammer and G. L. Greene and P. R. Huffman and A. T. Holley and G. L. Jones and C. -Y. Liu and M. Makela and M. P. Mendenhall and C. L. Morris and J. Mulholland and K. M. Nollett and R. W. Pattie, and S. Penttila and M. Ramsey-Musolf and D. J. Salvat and A. Saunders and S. J. Seestrom and W. M. Snow and A. Steyerl and F. E. Wietfeldt and A. R. Young and A. T. Yue},
journal= {arXiv preprint arXiv:1410.5311},
year = {2014}
}