• Milestone

Measurement of the neutron-neutron scattering length using the πd capture reaction

Q. Chen, C. R. Howell, T. S. Carman, W. R. Gibbs, B. F. Gibson, A. Hussein, M. R. Kiser, G. Mertens, C. F. Moore, C. Morris, A. Obst, E. Pasyuk, C. D. Roper, F. Salinas, H. R. Setze, I. Slaus, S. Sterbenz, W. Tornow, R. L. Walter, C. R. Whiteley, and M. Whitton
Phys. Rev. C 77, 054002 – Published 23 May 2008
An article within the collection: Physical Review C 50th Anniversary Milestones

Abstract

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 πd 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 πd 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.

  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
14 More
  • Received 13 March 2008

DOI:https://doi.org/10.1103/PhysRevC.77.054002

©2008 American Physical Society

Collections

This article appears in the following collection:

Physical Review C 50th Anniversary Milestones

This collection of milestone papers from PRC highlights research that remains central to current developments in nuclear physics.

Authors & Affiliations

Q. Chen1,*, C. R. Howell1, T. S. Carman2, W. R. Gibbs3, B. F. Gibson4, A. Hussein5, M. R. Kiser1, G. Mertens6, C. F. Moore7, C. Morris4, A. Obst4, E. Pasyuk8, C. D. Roper1,†, F. Salinas1,‡, H. R. Setze1,§, I. Slaus9, S. Sterbenz4, W. Tornow1, R. L. Walter1, C. R. Whiteley7, and M. Whitton4,∥

  • 1Duke University and Triangle Universities Nuclear Laboratory, Durham, North Carolina
  • 2Lawrence Livermore National Laboratory, Livermore, California
  • 3New Mexico State University, Las Cruces, New Mexico
  • 4Los Alamos National Laboratory, Los Alamos, New Mexico
  • 5University of Northern British Columbia, Canada
  • 6University of Tübingen, Tübingen, Germany
  • 7University of Texas, Austin, Texas
  • 8Joint Institute of Nuclear Research, Dubna, Russia
  • 9Rudjer Boskovic Institute, Zagreb, Croatia

  • *Present address: MCI, Ashburn, VA.
  • Present address: Bettis Atomic Power Laboratory, West Mifflin, PA.
  • Present address: MCI, Clinton, MS.
  • §Present address: Pearl River Community College, Poplarville, MS.
  • Deceased.

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 77, Iss. 5 — May 2008

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review C

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×