Parton shower dislikes ew clustering

[Frank Krauss]

Problem in tt production plus decay at LHC, run card attached. Output below.

Exception_Handler::SignalHandler: Signal (11) caught. Exception_Handler::GenerateStackTrace(..): Generating stack trace {

0x7fa5ff7ff1fb in 'CSSHOWER::Parton::FollowUp()' (Parton.C:48) 0x7fa5ff3c399c in 'CSSHOWER::Shower::ReconstructDaughters(CSSHOWER::Singlet*, int, CSSHOWER::Parton*, CSSHOWER::Parton*)' (Shower.C:100) 0x7fa5ff3c554f in 'CSSHOWER::Shower::UpdateDaughters(CSSHOWER::Parton*, CSSHOWER::Parton*, CSSHOWER::Parton*, int)' (Shower.C:244) 0x7fa5ff3c65ad in 'CSSHOWER::Shower::MakeKinematics(CSSHOWER::Parton*, ATOOLS::Flavour const&, ATOOLS::Flavour const&, ATOOLS::Flavour const&, int)' (Shower.C:351) 0x7fa5ff3c7bb8 in 'CSSHOWER::Shower::EvolveSinglet(CSSHOWER::Singlet*, unsigned long const&, unsigned long&)' (Shower.C:475) 0x7fa5ff1967e8 in 'CSSHOWER::CS_Shower::PerformShowers(unsigned long const&, unsigned long&)' (CS_Shower.C:115) 0x7fa6006da6a1 in 'SHERPA::Perturbative_Interface::PerformShowers()' (Perturbative_Interface.C:263) 0x7fa601e856d2 in 'SHERPA::Jet_Evolution::AttachShowers(ATOOLS::Blob*, ATOOLS::Blob_List*, SHERPA::Perturbative_Interface*)' (Jet_Evolution.C:163) 0x7fa601e860fd in 'SHERPA::Jet_Evolution::Treat(ATOOLS::Blob_List*, double&)' (Jet_Evolution.C:107) 0x7fa601e773c9 in 'SHERPA::Event_Handler::IterateEventPhases(double&)' (Event_Handler.C:190) 0x7fa601e7a5ae in 'SHERPA::Event_Handler::GenerateStandardPerturbativeEvent(SHERPA::eventtype::code&)' (Event_Handler.C:246) 0x7fa601e7b0ad in 'SHERPA::Event_Handler::GenerateEvent(SHERPA::eventtype::code)' (Event_Handler.C:136) 0x7fa6020ada0b in 'SHERPA::Sherpa::GenerateOneEvent(bool)' (Sherpa.C:255) 0x401a87 in 'main' (Main.C:38)

} Cannot continue.

[Frank Siegert]

Isn't this the same issue as #112 which we discussed recently wrt tth? Check the debug output and compare to the one in #112. Btw... do you really want the hadronic decay channels? I think those should be the ones causing your crash, right?

[Frank Krauss]

No, i think this is different. Or do you want to say that hadronic (inclusive) decays do not work?

[Stefan Hoeche]

The shower cannot handle off-shell decays from the decay handler so far. If you want to do this you have to use ME decays. On top of that there are invalid clusterings from the decay handler H->t->Wb, which violate color conservation.