The automatic computation for SUSY processes

We have constructed a system for the automatic computation of cross-sections for the processes of the SUSY QED by the extension of the GRACE system including a Majorana fermion. The system has also been applied to another model including Majorana fermions, MSSM, by the definition of the model file.Comment: total 4 page

Is a high PTP_T muon of the e+p→μ+Xe^+p \to \mu^+ X event observed at HERA a signature of the stop?

We investigate the $e^+p \to \mu^+ X$ event with high transverse momenta observed at HERA (H1) and show that this event could be interpreted as a signature of the single production of the scalar top quark in a supersymmetric model with $R$-parity breaking interactions. The event topology of the H1 event is rather characteristic and in fact it can be simulated by our specific scenario if we reasonably choose our model parameters to be ({\romannumeral 1}) $m_{{\widetilde{d}},{\widetilde{b}}, {\widetilde{\nu}}}$ ${{\stackrel{>}{\sim}}}$ $1$TeV [$0.8$TeV] for ${\lambda'_{131}}$ $=$ $0.1$ [$0.05$] and ({\romannumeral 2}) $m_{{\widetilde{W}}_{1}}$ ${{\stackrel{<}{\sim}}}$ $150$GeV, $100$GeV ${{\stackrel{<}{\sim}}}$ $m_{{\widetilde{t}}_1}$ ${{\stackrel{<}{\sim}}}$ $200$GeV and ${\lambda'_{131}}$ ${{\stackrel{>}{\sim}}}$ $0.05$.Comment: 8 pages, LaTeX, 4 figures (included in a separate .uu file