| Project/Area Number |
15340089
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Particle/Nuclear/Cosmic ray/Astro physics
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| Research Institution | RIKEN |
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Principal Investigator |
EN'YO Hideto RIKEN, Radiation Laboratory, Chief Scientist, 延與放射線研究室, 主任研究員 (30213606)
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| Co-Investigator(Kenkyū-buntansha) |
YOKKAICHI Satoshi RIKEN, Radiation Laboratory, Contract Researcher, 延與放射線研究室, 協力研究員 (20360670)
MUTO Ryotaro RIKEN, Radiation Laboratory, Special Postdoctoral Fellow, 延與放射線研究室, 基礎科学特別研究員 (50392147)
OHTANI Munehisa RIKEN, Radiation Laboratory, Contract Researcher, 延與放射線研究室, 協力研究員 (70373280)
NARUKI Megumi RIKEN, Radiation Laboratory, Special Postdoctoral Fellow, 延與放射線研究室, 基礎科学特別研究員 (00415259)
小沢 恭一郎 国立大学法人東京大学, 大学院・理学系研究科, 助手 (20323496)
谷田 聖 独立行政法人理化学研究所, 放射線研究室, 研究員 (00360587)
舟橋 晴彦 京都大学, 大学院・理学研究科, 助手 (00283581)
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| Project Period (FY) |
2003 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥10,900,000 (Direct Cost: ¥10,900,000)
Fiscal Year 2005: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 2004: ¥4,200,000 (Direct Cost: ¥4,200,000)
Fiscal Year 2003: ¥4,700,000 (Direct Cost: ¥4,700,000)
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| Keywords | phi meson / chiral symmetry / nuclear matter / media effect / invariant mass / electron pair |
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| Research Abstract |
This research project is to complete the data analyses of the experiment KEK-PS-E325 which has been performed to search for the modification of spectral shape of vector mesons in nuclear matter, in 12 GeV proton-nuclear reactions. Such phenomena are theoretically predicted in term of partial restoration of chiral symmetry in nuclear media.
Through the present research project, we have completed the data analyses for all the data we have acquired, and have reported "Experimental signature of the medium modification for rho and omega mesons in 12-GeV p + A reactions" in Phys. Rev. Lett. with 100 times higher statistics and reconfirmed our previous publicafirst results.
We have also discovered the modification of phi meson for the first time, and the paper "First observation of in-medium modification of phi meson at normal nuclear density" was published in Phys. Rev. Lett.
We have also obtained the absolute production cross section for omega and phi mesons as functions of transverse momentum and rapidity, and the paper the paper "Nuclear mass number dependence of inclusive production of omega and phi mesons in 12-GeV p + A collisions" was published in Phys. Rev. C. This paper is not sensational, but very important to give the basis of our discoveries described above. We have also compared K+K-decays and e+e-decays of phi meson. This result reads to the discussion on the modification of decay branch in nuclear matter. The paper is was published in Phys. Rev. Lett.
All the goals of the present experiment have been reached, and we will summarize all our results in the full paper near future. We conclude that the present research project is successfully concluded with new and important discoveries.
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