Tau decay branching ratios are initialized in INITDK which is called in TAUINT. The default INITDK in the standard TAUOLA distribution assumes equal branching to all the implemented decay modes. The branching ratios has thus to be adjusted by users according to PDG data or to the results from high statistics TAUOLA runs: the TAUOLA run summary contains the estimated branching ratio to each of the implemented decay modes. The INITDK routine in the current stand-alone version has a reasonably accurate branching ratios for major decay modes but as for rare decay modes the accuracies are questionable. If such rare decay modes are important to your application, you have to rewrite the INITDK routine accordingly.
The currently used branching ratios are summarized the table below where you can identify the decay mode corresponding to each JAK values.
JAK Decay Mode BR/BR(1) ------------------------------------------------- 1 TAU- --> ELECTRON 1.0000 2 TAU- --> MUON 0.9696 3 TAU- --> PION 0.6058 4 TAU- --> RHO (->2PI) 1.3274 5 TAU- --> A1 (->3PI) 0.7194 6 TAU- --> KAON 0.0398 7 TAU- --> K* 0.0702 8 TAU- --> 2PI-, PI0, PI+ 0.0840 9 TAU- --> 3PI0, PI- 0.0172 10 TAU- --> 2PI-, PI+, 2PI0 0.0634 11 TAU- --> 3PI-, 2PI+, 0.0289 12 TAU- --> 3PI-, 2PI+, PI0 0.0042 13 TAU- --> 2PI-, PI+, 3PI0 0.0042 14 TAU- --> K-, PI-, K+ 0.0061 15 TAU- --> K0, PI-, K0B 0.0056 16 TAU- --> K-, K0, PI0 0.0005 17 TAU- --> PI0, PI0, K- 0.0061 18 TAU- --> K-, PI-, PI+ 0.0315 19 TAU- --> PI-, K0B, PI0 0.0319 20 TAU- --> ETA, PI-, PI0 0.0109 21 TAU- --> PI-, PI0, GAM 0.0032 22 TAU- --> K-, K0 0.0181 -------------------------------------------------