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method I

Amplitudes of final six-body process are produced by the GRACE system. In order to reduce a number of unnecessary diagrams, we prepared very restricted model file as;

We got 108 diagrams as shown in Figs.1-4. Among these diagrams our target process is graph 6, as shown in Fig.5. We have not checked contributions from other diagrams. We guess that after simple mass cuts the contributions form background diagrams may be small. (Checking a contribution from other diagrams are also very interesting job, but for another chance.)

Cross sections are calculated based on an amplitude of graph 6 with exact six-body kinematics. For this method, the width of each intermediate particle had to be set carefully. In this report, the width of tex2html_wrap_inline532 is set to be a partial width of tex2html_wrap_inline494 via tex2html_wrap_inline552. Other contributions of tex2html_wrap_inline494 via tex2html_wrap_inline556, tex2html_wrap_inline558, tex2html_wrap_inline560, and tex2html_wrap_inline562 are ignored. A total width of tex2html_wrap_inline532 is calculated to be tex2html_wrap_inline566 GeV when slepton masses are 1TeV. A width of tex2html_wrap_inline530 is set to be a total width of tex2html_wrap_inline570'. A pair of f f' comes from W boson decay, then a branching ratio of tex2html_wrap_inline534 must be 1/9. A width of W boson is large compared with a Q-value of a tex2html_wrap_inline490 decay.
The decay width of tex2html_wrap_inline490 is calculated to be tex2html_wrap_inline584GeV, which is 13% smaller than the width of tex2html_wrap_inline534. The effect of virtuality of a W boson cannot be neglected in the total width calculations.

Total cross sections with/without the proton structure-function are summarized in Table 1. Distributions obtained with the HMRS(E) structure function are shown in Figs.7-8.

1998年07月06日 (月) 12時50分17秒 JST