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.
Laboratory of Nuclear Problems, Joint Institute for Nuclear Research, 141980 Dubna, Russia.
V
V
Komarov
T
T
Azaryan
D
D
Chiladze
S
S
Dymov
A
A
Dzyuba
M
M
Hartmann
A
A
Kacharava
I
I
Keshelashvili
A
A
Khoukaz
A
A
Kulikov
V
V
Kurbatov
G
G
Macharashvili
S
S
Merzliakov
S
S
Mikirtychiants
M
M
Papenbrock
M
M
Nekipelov
F
F
Rathmann
V
V
Serdyuk
H
H
Ströher
D
D
Tsirkov
Yu
Y
Uzikov
C
C
Wilkin