Opened 11 years ago
Closed 11 years ago
#531 closed defect (fixed)
Handle unphysical kinematics
| Reported by: | kilian | Owned by: | kilian |
|---|---|---|---|
| Priority: | P0 | Milestone: | v2.2.0 |
| Component: | core | Version: | 2.1.1 |
| Severity: | critical | Keywords: | |
| Cc: |
Description
In an attempt to compute a process with four particles, e.g., e+ e- -> u dbar mu- nu_mu, WHIZARD aborts with the message
Failed kinematics (not implemented yet)
This occurs if a momentum set is outside the physical region. For these points, the evaluation chain should be skipped, and the matrix element set zero.
Simple processes (up to 2->3) are apparently not affected.
It is rather simple to fix this, but the flags have to be set in the proper places. Just setting the phase space to zero does not work because of variables which are then undefined.
I'd suggest: finalize the alpha version anyway, with the big caveat to use it only for simple tests. It can, at least, be used for finding bugs and identifying more critical issues in the workflow.
Finally, it wasn't hard to fix this. The test smtest_2 (four-fermion production in e+e-) is sensitive to the effect, it failed before the fix. The result of smtest_2 has been verified against Whizard 2.1. (In the test run, the number of iterations is rather low, to keep the running time of the test suite short, but the result is meaningful.)
Fixed in r4617.