Observation of a large reaction cross section in the drip-line nucleus 22C.
Reaction cross sections (sigma(R)) for 19C, 20C and the drip-line nucleus 22C on a liquid hydrogen target have been measured at around 40A MeV by a transmission method. A large enhancement of sigma(R) for 22C compared to those for neighboring C isotopes was observed. Using a finite-range Glauber calculation under an optical-limit approximation the rms matter radius of 22C was deduced to be 5.4+/-0.9 fm. It does not follow the systematic behavior of radii in carbon isotopes with N < or = 14, suggesting a neutron halo. It was found by an analysis based on a few-body Glauber calculation that the two-valence neutrons in 22C preferentially occupy the 1s(1/2) orbital.
Tanaka
K
K
RIKEN Nishina Center, Saitama 351-0198, Japan.
Yamaguchi
T
T
Suzuki
T
T
Ohtsubo
T
T
Fukuda
M
M
Nishimura
D
D
Takechi
M
M
Ogata
K
K
Ozawa
A
A
Izumikawa
T
T
Aiba
T
T
Aoi
N
N
Baba
H
H
Hashizume
Y
Y
Inafuku
K
K
Iwasa
N
N
Kobayashi
K
K
Komuro
M
M
Kondo
Y
Y
Kubo
T
T
Kurokawa
M
M
Matsuyama
T
T
Michimasa
S
S
Motobayashi
T
T
Nakabayashi
T
T
Nakajima
S
S
Nakamura
T
T
Sakurai
H
H
Shinoda
R
R
Shinohara
M
M
Suzuki
H
H
Takeshita
E
E
Takeuchi
S
S
Togano
Y
Y
Yamada
K
K
Yasuno
T
T
Yoshitake
M
M