Test of non-perturbative QCD by means of the measurement of Kπ scattering length -Extension of DIRAC experiment-

通过测量 Kπ 散射长度来测试非微扰 QCD -DIRAC 实验的扩展 -

基本信息

批准号：
14340079
负责人：
TAKEUTCHI Fujio
金额：
$ 9.22万
依托单位：
Kyoto Sangyo University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14340079/
关键词：
DIRAC experiment CERN PS212 Non-perturbative QCD Scattering length of pion hadronic atom Kπ atom Scifi hodoscope Silicon microstrip counter π^-π^+原子 Κπ原子 PS212 QCD 二中間子原子カイラル摂動理論 S波散乱波長 CERN・PS

项目摘要

The principal objective of this study is to carry out PS212 (DIRAC) experiment at CERN to test the non-perturbative QCD in the low-energy region. It is essential to test the theory experimentally to understand thoroughly the hadron interactions. Although is difficult to carry out reliable calculations in this region, the π-π scattering length is predicted with an exceptional precision, better than 2%. DIRAC experiment aims at measuring the pi-pi scattering length with a precision of 5% by measuring the life-time of the A_<2π> atom.During the period of this project, the Japanese group pursued the experiment by improving the experimental setup. Parts of the experimental result have been already analyzed and published.The collaboration undertakes a measurement of the life time of atoms formed with K and π by applying the same technique used in DIRAC. The production cross section of such atoms, however, is much smaller, and the measurement requires the development of detectors efficient in much larger beam intensities.To solve the saturation problem of the current dE/dx counter, a fast silicon strip counter which allows a use in triggering is developed, and now it is ready. Also a scintillating fiber hodoscope using 0.28 mmΦ scintillator in stead of current 0.5 mmΦ one, and a fast readout system using F1-TDC have been developed. The detector has now an efficiency of 98%, spatial resolution of 64 μm together with a time resolution better than 500 ps, and it can be used as a tracking device as well as a triggering device.With the development of these counters together with micro drift chamber developed by the Russian group, the detection of A_<Kπ> became possible, and the project to carry out this experiment as an extension of DIRAC has been approved in December 2005. A serious preparation is in progress.

这项研究的主要目的是在CERN进行PS212（DIRAC）实验，以测试低能量区域的非扰动QCD。在实验上测试该理论是必不可少的，以便准确了解强子相互作用。尽管很难在该区域进行可靠的计算，但是π-π散射长度的预测具有特殊的精度，高于2％。 Dirac实验旨在通过测量A_<2π>原子的寿命来测量Pi-Pi散射长度。实验结果的一部分已经进行了分析和发表。该协作通过应用与DIRAC中使用的相同技术来对用K和π形成的原子的寿命进行测量。但是，这种原子的生产横截面要小得多，并且测量需要在更大的光束强度中有效地开发探测器。要解决当前DE/DX计数器的饱和问题，这是一种快速的硅条带，可以开发触发触发器，现在就可以开发出来。还开发了使用0.28mmφ闪烁体的闪烁纤维hodoscope，代替了当前0.5mmφ1，并开发了使用F1-TDC的快速读数系统。现在，该检测器的效率为98％，空间分辨率为64μm，时间分辨率大于500 PS，并且可以用作跟踪设备以及触发装置。这些计数器的开发与俄罗斯集团开发的微型驾驶员室的开发以及批准了A_<kπ>的批准，并进行了2005年的批准。正在进行中。