Problems with one loop decays

Questions about the interface between SARAH and SPheno as well as the FlavorKit functionality
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PhilipDiessner
Posts: 4
Joined: 14. Jul 2017, 12:07

Problems with one loop decays

Post by PhilipDiessner » 24. Apr 2018, 15:18

Hey Florian,

I am having some rather strange issues with the one loop decay widths where some the channels seem not to appear
for me. I attach my SPheno output for the MSSM default using freshly downloaded SARAH 4.12.3 and SPheno 4.0.3.

Most notable are the decay of the top quark missing the main final state and the Higgs missing bbar.
Have you seen this before and/or any idea what I am doing wrong?

Cheers Philip
Attachments
spc.txt
(85.69 KiB) Downloaded 150 times

FStaub
Site Admin
Posts: 822
Joined: 13. Apr 2016, 14:05

Re: Problems with one loop decays

Post by FStaub » 30. Apr 2018, 15:28

Hi Philipp,

that sounds strange. Did you try to look at the debug output? Putting flag 1103 to one, you see the values of the different pieces. Maybe, that helps to locate the problem.

Cheers,
Florian

PhilipDiessner
Posts: 4
Joined: 14. Jul 2017, 12:07

Re: Problems with one loop decays

Post by PhilipDiessner » 2. May 2018, 17:36

It seems like something is going wrong with the loop contributions as they are larger than the tree-level ones,
but are not included because they are quite often negative.
The top decay looks e.g. like this

Code: Select all

 ------------------ Fu->Fd conj[VWm] -----------------------
           3           1
 TREE x TREE:   0.28218357849087300     
 TREE x WAVE:   0.34934785430167420     
 TREE x VERTEX:   -4.3353411475606718     
 TREE x (TREE+WAVE+VERTEX):   -3.7038097147681239     
           3           2
 TREE x TREE:    13.418818578938646     
 TREE x WAVE:    18.671175059019522     
 TREE x VERTEX:   -155.62547295809065     
 TREE x (TREE+WAVE+VERTEX):   -123.53547932013248     
           3           3
 TREE x TREE:    8188.0507180939558     
 TREE x WAVE:    13030.747761126197     
 TREE x VERTEX:   -48911.484168844581     
 TREE x (TREE+WAVE+VERTEX):   -27692.685689624424  
 

FStaub
Site Admin
Posts: 822
Joined: 13. Apr 2016, 14:05

Re: Problems with one loop decays

Post by FStaub » 4. May 2018, 09:18

Hi,

the big negative numbers are actually not a problem, because they stll contain the IR divergent pieces. However, in one of the last updates an "eq" got exchanged by "le" what caused the problem. The patch is attached.

Cheers,
Florian
Attachments
SPhenoLoopDecays.m
(229.92 KiB) Downloaded 128 times

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