Observation of inverse diproton photodisintegration at intermediate energies.
The fundamental reaction pp-->{pp}_{s}gamma, where {pp}_{s} is a proton pair with low excitation energy, has been observed with the ANKE spectrometer at COSY-Jülich for proton beam energies of T_{p}=0.353, 0.500, and 0.550 GeV. This is equivalent to photodisintegration of a free 1S0 diproton for photon energies E_{gamma} approximately T_{p}/2. The differential cross sections measured for c.m. angles 0 degrees <theta_{pp}<20 degrees exhibit a steep increase with angle that is compatible with E1 and E2 multipole contributions. The ratio of the measured cross sections to those of np-->gammad is on the 10;{-3}-10;{-2} level. The increase of the pp-->{pp}_{s}gamma cross section with T_{p} might reflect the influence of the Delta(1232) excitation.
Komarov
V
V
Laboratory of Nuclear Problems, Joint Institute for Nuclear Research, 141980 Dubna, Russia.
Azaryan
T
T
Chiladze
D
D
Dymov
S
S
Dzyuba
A
A
Hartmann
M
M
Kacharava
A
A
Keshelashvili
I
I
Khoukaz
A
A
Kulikov
A
A
Kurbatov
V
V
Macharashvili
G
G
Merzliakov
S
S
Mikirtychiants
S
S
Papenbrock
M
M
Nekipelov
M
M
Rathmann
F
F
Serdyuk
V
V
Ströher
H
H
Tsirkov
D
D
Uzikov
Yu
Y
Wilkin
C
C