Experimental signature of medium modifications for rho and omega mesons in the 12 GeV p+A reactions.
The invariant mass spectra of e+e- pairs produced in 12 GeV proton-induced nuclear reactions are measured at the KEK Proton Synchrotron. On the low-mass side of the meson peak, a significant enhancement over the known hadronic sources has been observed. The mass spectra, including the excess, are well reproduced by a model that takes into account the density dependence of the vector meson mass modification, as theoretically predicted.
Naruki
M
M
Department of Physics, Kyoto University, Kitashirakawa Sakyo-ku, Kyoto 606-8502, Japan. naruki@nh.scphys.kyoto-u.ac.jp
Fukao
Y
Y
Funahashi
H
H
Ishino
M
M
Kanda
H
H
Kitaguchi
M
M
Mihara
S
S
Miwa
K
K
Miyashita
T
T
Murakami
T
T
Nakura
T
T
Sakuma
F
F
Togawa
M
M
Yamada
S
S
Yoshimura
Y
Y
En'yo
H
H
Muto
R
R
Tabaru
T
T
Yokkaichi
S
S
Chiba
J
J
Ieiri
M
M
Sasaki
O
O
Sekimoto
M
M
Tanaka
K H
KH
Hamagaki
H
H
Ozawa
K
K