Observation of rho/omega meson modification in nuclear matter.
We measured the invariant mass spectra of electron-positron pairs in the target rapidity region of 12-GeV p+A reactions. We have observed a significant difference in the mass spectra below the omega meson between p+C and p+Cu interactions. This difference indicates that the spectral shape of mesons is modified at normal nuclear-matter density.
Ozawa
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K
Department of Physics, Kyoto University, Kitashirakawa Sakyo-Ku, Kyoto 606-8502, Japan.
En'yo
H
H
Funahashi
H
H
Kitaguchi
M
M
Ishino
M
M
Kanda
H
H
Mihara
S
S
Miyashita
T
T
Murakami
T
T
Muto
R
R
Naruki
M
M
Sakuma
F
F
Sato
H D
HD
Tabaru
T
T
Yamada
S
S
Yokkaichi
S
S
Yoshimura
Y
Y
Chiba
J
J
Ieiri
M
M
Nomachi
M
M
Sasaki
O
O
Sekimoto
M
M
Tanaka
K H
KH
Hamagaki
H
H