2009 Fiscal Year Final Research Report
Search for Primordial Antiparticle with a balloon-borne experiment using a superconducting spectrometer at a solar minimum period
| Project/Area Number |
18104006
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| Research Category |
Grant-in-Aid for Scientific Research (S)
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| Allocation Type | Single-year Grants |
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| Research Field |
Particle/Nuclear/Cosmic ray/Astro physics
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| Research Institution | High Energy Accelerator Research Organization |
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Principal Investigator |
YAMAMOTO Akira High Energy Accelerator Research Organization, 超伝導低温工学センター, 教授 (30113418)
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| Co-Investigator(Kenkyū-buntansha) |
YOSHIMURA Koji 高エネルギー加速器研究機構, 素粒子原子核研究所, 準教授 (50272464)
MAKITA Yasuhiro 高エネルギー加速器研究機構, 素粒子原子核研究所, 準教授 (30199658)
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| Project Period (FY) |
2006 – 2009
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| Keywords | 宇宙起源 / 反粒子 / 反物質 / 超伝導 / スペクトロメータ / 南極周回 / 気球飛翔 |
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| Research Abstract |
The research program by using the Balloon-borne Experiment with a Superconducting Spectrometer (BESS) has much progressed with a long duration flight over Antarctica at soar minimum period in 2007～2008 (BESS-Polar II), as summarized as follows : (1) The antiproton spectrum measured shows good consistency with secondary antiproton model calculation. (2) Given this background of secondary antiprotons, cosmologically primary antiprotons have been searched for using the observed antiproton spectrum. The result show no evidence of primary antiprotons that originated from the evaporation of Primordial Black Holes within the obtained statistics. (3) No anti-helium candidate was detected, and a resultant up limit of 7x10E-8 for the abundance ratio of anti-helium/helium in a rigidity range of 1-14 GV by combining all the BESS and BESS-Polar data. This the most stringent limit obtained to date.
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