Exclusive p Production with BoNuS

1
Exclusive p- Production with BoNuS

• Gail Dodge and Jixie Zhang

2
Motivation

• Clean access to the n?pp- channel by tagging the
  spectator proton
• Study neutron resonances
• There are no data now
• The neutron data that go into models like SAID
  are a few old measurements of p/p- ratios on
  deuterium.

3
quasi-free
primary background
p
This final state interaction is small for low
momentum ps and has a very strong angular
dependence.
p0
p
p-
d
p
4
Calculations by Laget
R
R
momentum of ps
qr angle between ps and q
R ratio of total to quasi-free cross section
for D(g,p-p)p
5
Strategy

• Detect ps in BoNuS and look at cross section for
  the D(e,ep-ps)p process as a function of qR.
• If it is flat, we can assume negligible
  contribution from FSI.
• Extract n?p-p cross section.
• Do this for bins in spectator proton momentum and
  look for the onset of FSI effects.

6
Experimental Conditions

• Prefer lower beam energies and outbending torus.
• Need to look at acceptance/rates it may make
  sense to go to PAC to request more beam time.
• Suggestions are welcome!