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Measurement of the neutron-neutron scattering length using the π-d capture reaction

Publication ,  Journal Article
Chen, Q; Howell, CR; Carman, TS; Gibbs, WR; Gibson, BF; Hussein, A; Kiser, MR; Mertens, G; Moore, CF; Morris, C; Obst, A; Pasyuk, E; Slaus, I ...
Published in: Physical Review C - Nuclear Physics
May 23, 2008

We have determined a value for the 1S0 neutron-neutron scattering length (ann) from high-precision measurements of time-of-flight spectra of neutrons from the H2(π-,nγ)n capture reaction. The measurements were done at the Los Alamos Meson Physics Facility by the E1286 Collaboration. The high spatial resolution of our γ-ray detector enabled us to make a detailed assessment of the systematic uncertainties in our techniques. The value obtained in the present work is ann=-18.63±0.10 (statistical) ± 0.44 (systematic) ± 0.30 (theoretical) fm. This result is consistent with previous determinations of ann from the π-d capture reaction. We found that the analysis of the data with calculations that use a relativistic phase-space factor gives a more negative value for ann by 0.33 fm over the analysis done using a nonrelativistic phase-space factor. Combining the present result with the previous ones from π-d capture gives ann=-18.63±0.27(expt) ±0.30 fm (theory). For the first time the combined statistical and systematic experimental uncertainty in ann is smaller than the theoretical uncertainty and comparable to the uncertainty in the proton-proton 1S0 scattering length (app). This average value of ann when corrected for the magnetic-moment interaction of the two neutrons becomes -18.9 ± 0.4 fm, which is 1.6 ± 0.5 fm different from the recommended value of app, thereby confirming charge symmetry breaking at the 1% confidence level. © 2008 The American Physical Society.

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Published In

Physical Review C - Nuclear Physics

DOI

EISSN

1089-490X

ISSN

0556-2813

Publication Date

May 23, 2008

Volume

77

Issue

5

Related Subject Headings

  • Nuclear & Particles Physics
  • 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics
 

Citation

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Chen, Q., Howell, C. R., Carman, T. S., Gibbs, W. R., Gibson, B. F., Hussein, A., … Whitton, M. (2008). Measurement of the neutron-neutron scattering length using the π-d capture reaction. Physical Review C - Nuclear Physics, 77(5). https://doi.org/10.1103/PhysRevC.77.054002
Chen, Q., C. R. Howell, T. S. Carman, W. R. Gibbs, B. F. Gibson, A. Hussein, M. R. Kiser, et al. “Measurement of the neutron-neutron scattering length using the π-d capture reaction.” Physical Review C - Nuclear Physics 77, no. 5 (May 23, 2008). https://doi.org/10.1103/PhysRevC.77.054002.
Chen Q, Howell CR, Carman TS, Gibbs WR, Gibson BF, Hussein A, et al. Measurement of the neutron-neutron scattering length using the π-d capture reaction. Physical Review C - Nuclear Physics. 2008 May 23;77(5).
Chen, Q., et al. “Measurement of the neutron-neutron scattering length using the π-d capture reaction.” Physical Review C - Nuclear Physics, vol. 77, no. 5, May 2008. Scopus, doi:10.1103/PhysRevC.77.054002.
Chen Q, Howell CR, Carman TS, Gibbs WR, Gibson BF, Hussein A, Kiser MR, Mertens G, Moore CF, Morris C, Obst A, Pasyuk E, Roper CD, Salinas F, Setze HR, Slaus I, Sterbenz S, Tornow W, Walter RL, Whiteley CR, Whitton M. Measurement of the neutron-neutron scattering length using the π-d capture reaction. Physical Review C - Nuclear Physics. 2008 May 23;77(5).

Published In

Physical Review C - Nuclear Physics

DOI

EISSN

1089-490X

ISSN

0556-2813

Publication Date

May 23, 2008

Volume

77

Issue

5

Related Subject Headings

  • Nuclear & Particles Physics
  • 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics