https://doi.org/10.1140/epja/i2008-10662-x
Regular Article - Experimental Physics
np → ηd near threshold and the s -wave ηN amplitude
1
Instituto Politécnico Nacional, Escuela Superior de Fısica y Matemáticas, Edificio 9, 07738, México D.F., Mexico
2
Instituto Superior Técnico, Centro de Fısica Teórica de Partıculas, and Department of Physics, Av. Rovisco Pais, 1049-001, Lisboa, Portugal
* e-mail: humberto@esfm.ipn.mx
Received:
26
June
2008
Revised:
22
September
2008
Accepted:
10
October
2008
Published online:
30
October
2008
We calculate the process np → ηd near threshold using a separable potential model of the coupled ηN - πN - ππN subystems, and a relativistic three-body calculation for the ηd scattering amplitude. The ππN channels are represented by an effective σN channel, and we compare the case where the σ and π masses are related by m σ = 2m π and no width is considered, to another where the mass and width of the σ -meson are taken from ππ scattering data. The np → ηd cross-section can be well described up to about 60MeV by models where the real part of the ηN scattering length lies between 0.4≤Re(a ηN)≤0.6 fm which allows us to determine the s -wave ηN scattering amplitude for -60≤E≤60 MeV.
PACS: 21.30.Fe Forces in hadronic systems and effective interactions – / 21.45.-v Few-body systems – / 25.10.+s Nuclear reactions involving few-nucleon systems – / 11.80.Jy Many-body scattering and Faddeev equation –
© SIF, Springer-Verlag Berlin Heidelberg, 2008