Observation of Cosmic-Ray Antiprotons by Emulsion Chamber

用乳化室观测宇宙射线反质子

• 批准号: 63540227
• 负责人: TATEYAMA Nobuhito
• 金额: $ 1.09万
• 依托单位: Kanagawa University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1988
• 资助国家: 日本
• 起止时间: 1988 至 1989
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-63540227/
• 关键词: Cosmicray antiproton; Antiproton; Nuclear emulsion experiment; 荷電粒子飛跡解析; 画像自動解析; 低エネルギ-反陽子; 荷電粒子飛跡自動解析; 低エネルギー一次宇宙線

The observation of the low-energy antiprotons would have profound implications for cosmology and propagation of the cosmic rays. Especially in the energy range less than 300 Mev, production of secondary antiproton is suppressed in a gaeactic space by the kinematical limit and the abundance of antiproton present us the key to the problem. The experimental results of antiproton-proton ratio (P/P) for energies less than 1 GeV have been already reported by several authors and the upper limit of P/P is 2.8X10^<-5>. However, those are inconsistent with each other and present us problems to current cosmological models, closed galaxy model and leaky-box model and other models. Our experiment to search for antiprotons in this energy region has been carried out with the emulsion stack flown by the balloon from Prince Albert, Saskatchewan, Canada in August 1987. Cut-off energy is 170 MeV. The exposure by the flight achieved about 22.5 hours at an altitude of 37 km.Detection of antiprotonThe incid … More ent cosmic ray particles make 'stars' in the emulsion stack. Among them, the antiproton stop in the emulsion shows the characteristic pattern ; 'bend' just before the vertex point. The data of branching ratios for pp annihilation at rest shows that over ninety percent of annihilation produce more than 2 charged pions. So we define the antiproton candidate that shows the 'bend' near the vertex with more than 2 charged particles. When we make an microscope examination, there are two processes to get the antiproton candidate among many charged tracks and background. At first, we scan a emulsion by microscope with automatic image processing and select the charged tracks from background. In this process, 12 pictures, obtained by changing a focus under 250 magnifications, are processed by background reduction and are reconstructed to one image with charged tracks. The second, this imageis reprocessed with Hough-transformation and the antiproton candidates selected by its pattern.result(1) We developed the advanced image processing technique to scan charged particles in emulsion and reconstructed tracks.(2) The total volume of emulsion in which we have scanned is 1.18 cm3. We have number distribution of secondary particles and the number distribution of secondary particles in 'bend' events. We have not obtained antiproton candidate.We get result the behavior of primary cosmic ray particles in the stack by simulation. We can expect the p/p ratio in the energy region between 170 Mev and 300 Mev to 2.6X10^<-5> by the comparison with simulation. Less

低能反质子的观测将对宇宙学和宇宙射线的传播产生深远的影响。特别是在300 Mev以下的能量范围内，次级反质子的产生受到运动学极限的抑制，反质子的丰度为我们提供了解决问题的关键。能量小于1GeV的反质子-质子比（P/P）的实验结果已被几位作者报道过，其上限为2.8 × 10 ~（-1）^<-5>。然而，这两种模型之间的矛盾给现有的宇宙学模型、封闭星系模型和漏盒模型等提出了问题。1987年8月，我们用从加拿大萨斯喀彻温省阿尔伯特亲王乘气球飞行的乳胶堆进行了在这个能区寻找反质子的实验。截止能量为170 MeV。在37公里的高度上，飞行暴露时间达到22.5小时。 ...更多信息 宇宙射线粒子在乳胶堆中形成“星星”。其中，乳胶中的反质子终止在顶点前显示出“弯曲”的特征模式。静止时pp湮灭的分支比数据表明，超过90%的湮灭产生2个以上的带电π介子。因此，我们定义的反质子候选人显示的“弯曲”附近的顶点与超过2个带电粒子。在进行显微镜检查时，从众多带电径迹和背景中得到候选反质子有两个过程。首先，我们用自动图像处理的显微镜扫描乳剂，从背景中选择带电径迹。在该过程中，通过在250倍放大率下改变焦点而获得的12个图片通过背景减少而被处理，并且被重构为具有带电轨迹的一个图像。结果（1）发展了先进的图像处理技术，可以对乳胶中的带电粒子进行扫描，并重建出径迹。(2)我们扫描的乳剂总体积为1.18 cm 3。得到了二次粒子数分布和“弯曲”事例中二次粒子数分布。我们还没有得到候选的反质子，通过模拟得到了初级宇宙线粒子在堆中的行为。通过与模拟结果的比较，我们可以预期在170 Mev和300 Mev之间的能区的p/p比为2.6 × 10 ↑ <-5>[3]。少

项目成果

平良,白井,立山,鳥居,他: "OBSERVATION OF COSMIC-RAY ANTIPROTONS BY EMULSION STACK" 21th In TERNATIONAL COSMIC RAY CONFERENCE,ADELAIDE,1990. 3. 281-283 (1990)

Taira、Shirai、Tateyama、Torii 等人：“通过乳液堆栈观察宇宙射线反质子”第 21 届国际宇宙射线会议，阿德莱德，1990. 3. 281-283 (1990)

T.Taira,T.Shirzi,N.Tateyama S.Torii,J.Nishimura,M.Fujii T.Kobayashi,H.Aizu,Y.Yoshimori S.Tasaka,A.Nishio: "OBSERVATION OF COSMICーRAY ANTIPROTONS BY EMULSION STACK" Proceedings of 21st International Cosmic Ray Conference. Vol.3. 281-283 (1990)

T.Taira，T.Shirzi，N.Tateyama S.Torii，J.Nishimura，M.Fujii T.Kobayashi，H.Aizu，Y.Yoshimori S.Tasaka，A.Nishio：“通过乳液观察宇宙射线反质子STACK”第 21 届国际宇宙射线会议论文集。第 3 卷。281-283 (1990)

T. Tira, T. Shirai, N. Tateyama, S. Torii, J. Nishimura, M. Fujii, T. Kobayashi, H. Aizu, Y. Komori, S. Tasaka, A. Nishio: ""Observation of cosmic-ray antiprotons by emulsion stack"" Proceedings of 21ST Internatonal cosmic ray conference. VoL. 3.281-283 (

T. Tira、T. Shirai、N. Tateyama、S. Torii、J. Nishimura、M. Fujii、T. Kobayashi、H. Aizu、Y. Komori、S. Tasaka、A. Nishio：“”宇宙观测-

平良俊雄: 一次電子研究会. 29-31 (1989)

Toshio Taira：初级电子研究小组。29-31 (1989)