ttbar + jets, strange output and taking a long time

[Generic User (don't modify these fields)]

Hey Sherpas,

I am an undergraduate student and I try to us SHERPA for my thesis. I want to produce ttbar with up to 3 jets, but right now I even have problems with 1 additional jet. I tried your suggestions in ticket #56. But after more than 30 minutes, I still have no events generated and I got strange output:

Process_Group::CalculateTotalXSec(): Calculate xs for '2_6jjt[W+[jj]b]tb[W-[jj]bb]' (Amegic) Starting the calculation. Lean back and enjoy ... . Channel_Basics::SqLam argument -11.2726 <0 in Channel_Basics::sqlam() s;s1;s2: 2.45623e+07;615.04;2.43171e+07 Channel_Basics::SqLam argument -0.000136197 <0 in Channel_Basics::sqlam() s;s1;s2: 615.04;23.04;400 Channel_Basics::SqLam argument nan <0 in Channel_Basics::sqlam() s;s1;s2: nan;23.04;521.192 Channel_Basics::SqLam argument nan <0 in Channel_Basics::sqlam() s;s1;s2: nan;0;0 Channel_Basics::SqLam argument nan <0 in Channel_Basics::sqlam() s;s1;s2: nan;23.04;3859.35 Channel_Basics::SqLam argument nan <0 in Channel_Basics::sqlam() s;s1;s2: nan;0;0 Phase_Space_Handler::Check4Momentum(..): Difference: (nan,nan,nan,nan) nan WARNING in Phase_Space_Handler::Differential : Check4Momentum(p) failed Channel_Elements::DiceYForward(0.00167183,{-8.98847e+307,0,-8.98847e+307,0,0},{-3.19692,3.19692,-0.894747}): Y out of bounds !

ymin, ymax vs. y : -3.19692 3.19692 vs. -3.19692

Setting y to lower bound ymin=-3.19692 Channel_Basics::SqLam argument -1.86488e-05 <0 in Channel_Basics::sqlam() s;s1;s2: 15614.3;695.024;9720.77 ThresholdMomenta out of bounds ! Channel_Elements::ThresholdMomenta 2 517.5 10000 4.9e+07 10000 0

I will attache my Run.dat file, shurely the problem is in there.

Thanks for your help

Claudius Krause

[Stefan Hoeche]

Dear Claudius,

I take it from your Run.dat that you intend to use Amegic. This is unfortunateley not possible due to the large final state multiplicity in the process you are trying to compute. Please switch to Comix instead by setting

ME_SIGNAL_GENERATOR   = Comix

in the (me) section of your input file. Apart from this change, the suggestions in ticket #56 still apply. Sorry for the delayed answer

Stefan

[Stefan Hoeche]

In case of further questions regarding this issue, please reopen the ticket.

[Stefan Hoeche]

Milestone rel-1.2.3 deleted