Measurements of n-p correlations in the reaction of relativistic neon with uranium.
We report a preliminary measurement of coincident neutron-proton pairs emitted at 45 degrees in the interaction of 400, 530, and 650 MeV/A neon beams incident on uranium.  Charged particles were identified by time of flight and momentum, as  determined in a magnetic spectrometer.  Neutral particles were detected using a thick plastic scintillator, and their time of flight was measured between an entrance scintillator, triggered by a charged particle, and the neutron detector.  The scatter plots and contour plots of neutron momentum vs. proton momentum appear to show a slight correlation ridge above an uncorrelated background.  The projections of this plane on the n-p momentum difference axis are essentially flat, showing a one standard deviation enhancement for each of the three beams energies.  At each beam energy, the calculated momentum correlation function for the neutron-proton pairs is enhanced near zero neutron-proton momentum difference by approximately one standard deviation over the expected value for no correlation.  This enhancement is expected to occur as a consequence of the attractive final state interaction between the neutron and proton (i.e., virtual or "singlet" deuterons).  The implications of these measurements are discussed.
Frankel
K
K
Lawrence Berkeley Laboratory, University of California, Berkeley, USA.
Schimmerling
W
W
Rasmussen
J O
JO
Crowe
K M
KM
Bistirlich
J
J
Bowman
H
H
Hashimoto
O
O
Murphy
D L
DL
Ridout
J
J
Sullivan
J P
JP
Yoo
E
E
McDonald
W J
WJ
Salomon
M
M
Xu
J S
JS
D004601:Elementary Particles; D008962:Models, Theoretical; D009356:Neon; D009502:Neutrons; D009686:Nuclear Physics; D011522:Protons; D013053:Spectrophotometry / Q000379:methods; D014501:Uranium
D011522:Protons; D014501:Uranium; D009356:Neon