Study of precise measurements of Higgs in linear collider

1.对Higss粒子的详细研究是国际直线对撞机实验的重要目标之一。有了实验者全力以赴的高统计数据，精确的理论计算是强制性的。利用微扰计算自动化系统(GRACE)计算了高能区Higgs势的全电弱辐射修正。Gμ格式计算的弱修正很小，对&gt；600GeV的修正不到5%。为了验证这一结果，我们对ZHH信道和vμvμHH信道进行了比较，并假定W-&GT；HH机制占优势，估计了弱校正。本文介绍了GRACE/SUSY-LOOP所采用的重整化方案及其特点，GRACE/SUSY-LOOP是一个自动计算最小超对称标准模型过程的程序包，包括单圈阶次修正。给出了用GRACE/SUSY-LOOP计算的单圈顺序的二体和三体衰变宽度。对大规模计算的数值精度的控制，如GRACE自动费曼图计算系统生成的计算，已经成为这些程序包的固有部分。在正负电子对撞机上，利用四倍和八倍精度的算术库进行了单圈辐射校正，得到了丢失比特数。我们开发了一个程序，该程序为其符号操作生成表单源代码。这使我们能够进行高效的内存管理，这对于处理大量的Feynman图是必不可少的，从而显著提高了性能。

1. One of the most important goals of the International Linear Collider experiments is the detailed study of Higss particle. With the high-statistics data from devoted efforts by experimentalists, precise theoretical calculations are mandatory. We calculated the full electroweak radiative corrections for Higgs potential in the high energy region using the automated system (GRACE) for the perturbative computation. The calculated weak correction in Gμ scheme is small, less than 5% for > 600GeV. In order to confirm the results, we have made the comparison between ZHH channel and vμvμHH channel, and also the estimation of the weak correction by assuming the dominance of W W -> HH mechanism.2. We present the renormalization scheme used in and the characteristic features of GRACE/SUSY-loop, the package of the program for the automatic calculation of the minimal supersymmetric standard model processes including one-loop order corrections. The two-body and three-body decay widths of charginos in one-loop order evaluated by GRACE/SUSY-loop are shown.3. The control of the numerical precision of large-scale computations like those generated by the GRACE system for automatic Feynman diagram calculations has become an instrinsic part of those packages. We tested the 1-loop radiative correction to electron positron tau anti-tau production in electon positron collider, using quadruple and octuple precision arithmetic library where the number of lost-bits is made available.4. We developed the program which generated FORM sources for its symbolic manipulation. This enables us the efficient memory management that is essential for the handling of a tremendous number of Feynman diagrams, so that the performance is significantly improved.