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First measurement of the spin transfer parameter K(n00n) in the anti-p p ---> anti-n n reaction at 875-MeV/c

Ahmidouch, A. ; Bertini, R. ; Birsa, R. ; et al.
Phys.Lett.B 380 (1996) 235-240, 1996.
Inspire Record 429760 DOI 10.17182/hepdata.5745

The spin-transfer parameter K n 00 n of the p p↑ → n ↑n charge exchange reaction has been measured for the first time at the CERN Low Energy Antiproton Ring (LEAR), at 875 MeV/ c p momentum, in the centre-of-mass scattering-angle range from 45° to 78°. To measure the transverse polarisation of the n 's, a thick scintillator counter hodoscope was used as live target, and the elastic n p scattering on the hydrogen of the scintillator was used as analysing reaction of the n transverse polarisation. Its so far unmeasured analysing power is taken as linear in momentum transfer, A n p = α·q , and results are given for α · K n 00 n . The values one obtains for K n 00 n , estimating α from N N potential models, are less than 0.25, in agreement with the predictions.

2 data tables
Table 1

Polarized beam. CONST is overall normalization unknown factor.

Table 2

No description provided.


First measurement of the anti-p p ---> anti-n n depolarization parameter D(0n0n) at 546-MeV/c and 875-MeV/c

Ahmidouch, A. ; Heer, E. ; Hess, R. ; et al.
Nucl.Phys.B 444 (1995) 27-58, 1995.
Inspire Record 405013 DOI 10.17182/hepdata.32839

The depolarization parameter Donon of the p dash p → n dash n charge exchange reaction has been measured for the first time at the CERN Low Energy Antiproton Ring (LEAR) at two antiproton momenta, 546 and 875 MeV/ c . The transverse polarization of the recoil neutron was analyzed using a large-acceptance neutron polarimeter made up of two parallel plastic scintillator planes. D 0 n 0 n is usually less than 0.35 which suggests that the spin-spin amplitudes dominate in the scattering matrix. Results are compared with the predictions of various N dash N potential models. The agreement is in general satisfactory.

2 data tables
Table 1

No description provided.

Table 2

No description provided.


First measurement of the depolarization parameter D(onon) of the anti-p p ---> anti-n n charge exchange reaction

Birsa, R. ; Bradamante, F. ; Bressan, A. ; et al.
Phys.Lett.B 302 (1993) 517-522, 1993.
Inspire Record 354498 DOI 10.17182/hepdata.28944

The depolarization parameter D 0 n 0 n in the charge-exchange reaction p p ↑→ n n ↑ has been measured for the first time at the CERN Low Energy Antiproton Ring (LEAR) at 875 MeV/ c antiproton beam momentum, in the forward hemisphere. The measured values of D 0 n 0 n are always smaller than ±0.3, indicating that the two-spin amplitudes dominate the scattering matrix as suggested by the meson exchange potential models.

1 data table
Table 1

No description provided.