2000 Fiscal Year Final Research Report Summary
Search for the σ meson by utilizing the Primakov effect
| Project/Area Number |
11440071
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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 |
素粒子・核・宇宙線
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| Research Institution | Osaka University |
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Principal Investigator |
SHIMIZU Hajime RCNP, Osaka Univ., Professor, 核物理研究センター, 教授 (20178982)
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| Co-Investigator(Kenkyū-buntansha) |
YOSOI Masaru RCNP, Osaka Univ., Research Associate, 核物理研究センター, 助手 (80183995)
FUJIWARA Mamoru RCNP, Osaka Univ., Associate Professor, 核物理研究センター, 助教授 (00030031)
NAKANO Takashi RCNP, Osaka Univ., Professor, 核物理研究センター, 教授 (80212091)
YOSHIDA Hiroshi Dep.of Phys., Yamagata Univ., Lecturer, 理学部, 講師 (80241727)
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| Project Period (FY) |
1999 – 2000
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| Keywords | σmeson / Primakov effect / EM calorimater / SPring-8 / Laser-electron photons / PWO crystals / Pb / SCIFI |
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| Research Abstract |
The aim of this research project was to measure the inverse process of σ→2γ by employing the Primakov effect. The main process to be measured is then γA→σX→π^0π^0X.Thus, in search for the σ meson, we have been working on design, construction and the performance test of a γ detector. That is the main part of the preparation for the study of the σ→π^0π^0 process. We have investigated 200 PWO crystals to be used as a forward γ detector in the fiscal year 2000.
A test experiment with a laser-electron photon beam is now successfully conducted at SPring-8. It turned out, however, that the call for proposals would be made in summer, 2001. And we expect that the experiment for our research project with the beam will be performed afterward. Therefore we could not help changing the schedule so as not to waste time. Namely, we started preparation for a measurement of the σ→π^0π^0 process at a backward angular region also. This measurement is complementary to that of Primakov production in the study of the σ meson.
We have constructed a backward γ detector consisting of 252 Pb/SCIFI blocks which covers the polar angle from 30° to 100°. This is an EM calorimeter of a kind of sampling detector covering a large solid angle of about 2π sr. Energy calibration for the detector has been made by utilizing π^0 events. Then the η peak is also observed. The mass resolution for π^0 and η are obtained to be 〜14% and 〜10%, respectively, for the moment.
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