College Park, Maryland      June 6 - 10 , 2004

ACNS Home Meeting Announcement Committees and Contacts Registration Abstract Submission Travel Reimbursement Dates to Remember

M4-B3 (4:30 PM): High-precision measurements of the n-p, n-d, and n-³He bound coherent scattering lengths

T. C. Black (University of North Carolina at Wilmington), P. R. Huffman (National Institute of Standards and Technology; North Carolina State University), M. Arif, D. L. Jacobson, S. A. Werner (National Institute of Standards and Technology), W. M. Snow (Indiana University; IUCF), K. Schoen (University of Missouri - Columbia)

Recent measurements of the n-d and n-³He bound coherent scattering lengths, conducted at the Neutron Interferometer and Optics Facility at NIST, are in significant disagreement with exact calculations of these observables using modern NN+3NF potentials. The bound coherent n-d scattering length was measured to be bnd = (6.665 ± 0.004) fm, which yields a new world average for this parameter of b_nd = (6.669 ± 0.003) fm. In the n-³He system, the bound coherent scattering length was measured as b_n-3He = (5.857 ± 0.007) fm, which yields a new world average for this parameter of b_n-3He = (5.854 ± 0.007) fm. Combining these measurements with O. Zimmer's result for the bound incoherent scattering length of b_i = (-2.365 ± 0.020) fm, one obtains the free singlet and triplet scattering lengths for the n-³He system; a₀ = (7.456 ± 0.026) fm, and a₁ = (3.364 ± 0.010) fm, respectively. Our measured value of the n-p bound coherent scattering length, b_np = (-3.7384 ± 0.0020) fm is in agreement with the previous world average value of b_np = (-3.7410 ± 0.0020)fm. The extreme precision of these new measurements renders them suitable for use in contemporary EFT calculations.

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