Evidence of , and meson mass modification in nuclear medium measured in 12 GeV p+A reaction at KEK-PS E325 RIKEN, Kyoto Univ. a , KEK b , CNS Univ. of Tokyo c , ICEPP Univ. of Tokyo d , Tohoku Univ. e Ryotaro Muto, KEK, Japan J. Chiba b , H. En’yo, Y. Fukao a , H. Funahashi a , H. Hamagaki c , M. Ieiri b , M. Ishino d , H. Kanda e , M. Kitaguchi a , S. Mihara d , K. Miwa a , T. Miyashita a , T. Murakami a , T. Nakura a , M. Naruki, K. Ozawa c , F. Sakuma a , O. Sasaki b , M. Sekimoto b , T. Tabaru, K.H. Tanaka b , M. Togawa a , S. Yamada a , S. Yokkaichi, Y. Yoshimura a (KEK-PS E325 Collaboration) • Introduction • Result of e + e - analysis • Result of e + e - analysis
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RIKEN, Kyoto Univ. a , KEK b , CNS Univ. of Tokyo c , ICEPP Univ. of Tokyo d , Tohoku Univ. e
RIKEN, Kyoto Univ. a , KEK b , CNS Univ. of Tokyo c , ICEPP Univ. of Tokyo d , Tohoku Univ. e Ryotaro Muto, KEK, Japan J. Chiba b , H. En’yo, Y. Fukao a , H. Funahashi a , H. Hamagaki c , M. Ieiri b , M. Ishino d , - PowerPoint PPT Presentation
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Evidence of , and meson mass modification in nuclear medium measured in
12 GeV p+A reaction at KEK-PS E325RIKEN, Kyoto Univ.a , KEKb, CNS Univ. of Tokyoc, ICEPP Univ. of Tokyod, Tohoku Univ.e
Ryotaro Muto, KEK, JapanJ. Chibab, H. En’yo, Y. Fukaoa, H. Funahashia, H. Hamagakic, M. Ieirib, M. Ishinod,
H. Kandae , M. Kitaguchia, S. Miharad, K. Miwaa, T. Miyashitaa, T. Murakamia, T. Nakuraa, M. Naruki, K. Ozawac, F. Sakumaa, O. Sasakib, M. Sekimotob, T. Tabaru, K.H. Tanakab, M. Togawaa, S. Yamadaa, S. Yokkaichi, Y. Yoshimuraa
(KEK-PS E325 Collaboration)
• Introduction• Result of e+e- analysis• Result of e+e- analysis
dropping mass• Brown-Rho scaling (’91)
– m*/m = 0.8 at = • QCD Sum Rule by Hatsuda & Lee (’92)
– m*/m = 1 - 0.16 for – m*/m = 1 - 0.03 0 for
• Lattice Calc. by Muroya, Nakamura & Nonaka(’03)
width broadening (at 0)• Klingl, Kaiser, Weise (’97-8)~ for
m/ decreases by 9.2%,m decreases by 3.4% and increases by 3.6 at 0
Best Fit Values
k19.2 ± 0.2% 3.4+0.6
-0.7%
k20 (fixed) 2.6+1.8
-1.2
Summary• We have observed significant excesses over the known hadronic
sources both in / e+e- and e+e- distributions in 12 GeV p+A reactions
• The excesses were well reproduced by the model calculation including mass modification,– / : 9% mass decrease– : 3% mass decrease and width broadening by a factor of 3.6
at 0.
• From K+K- analyses we have obtained limits on the in-medium decay width broadenings for both e+e- and K+K- decay channels
See Poster by Fuminori Sakuma (Tomorrow) • We are planning next experiment at J-PARC which will achieve
statistics 100 times as large as the present experiment