Nonzero Status for pp > WWW at NLO

Asked by Richard Ruiz

Hi Folks,

I am trying to simulate pp > www + madspin at NLO(+PS) but am getting yelled at by MINT for having a nonzero width. The thing is, I have no problem for tt or ttW and setting the W,Z,h, and t widths to zero in the param_card does not fix the issue. Details are below. Any suggestions on how to deal with this?

Thanks!

Best,
Richard

1. My version is:
version = 2.5.5
date = 2017-05-26

2. The proc card contains the following:
import model loop_sm
define p = g u c d s u~ c~ d~ s~
define ww = w+ w-
generate p p > ww ww ww [QCD]
output SM_pp_WWW_NLO

3. The run and param cards are the default files.

4. After launching, I get the following:
MG5_aMC>launch SM_pp_WWW_NLO
INFO: Cleaning previous results
INFO: Doing NLO matched to parton shower
INFO: Setting up grids
WARNING: program /.../MG5aMC_NLO_Current/SM_pp_WWW_NLO/SubProcesses/P0_udx_wpwpwm/ajob1 8 F 0 0 launch ends with non zero status: 1. Stop all computation

5. Running "ajob1 8 F 0 0" gives me the following log_MINT0.txt output in P0_udx_wpwpwm/GF8:

"Enter running mode for MINT:
0 to set-up grids, 1 to integrate, 2 to generate events
 MINT running mode: 0
Set the three folding parameters for MINT
STOP 1
xi_i, phi_i, y_ij
           1 1 1
 'all ', 'born', 'real', 'virt', 'novi' or 'grid'?
 Enter 'born0' or 'virt0' to perform
  a pure n-body integration (no S functions)
 doing the all of this channel
 Normal integration (Sfunction != 1)
 Error BW setting: not supported at NLO
Time in seconds: 1
"

Question information

Language:
English Edit question
Status:
Solved
For:
MadGraph5_aMC@NLO Edit question
Assignee:
marco zaro Edit question
Solved by:
Richard Ruiz
Solved:
Last query:
Last reply:
Revision history for this message
Richard Ruiz (rruiz) said :
#1

Update: This is still the when setting order=LO

Revision history for this message
Richard Ruiz (rruiz) said :
#2

 This is still the case* when setting order=LO

Revision history for this message
Rikkert Frederix (frederix) said :
#3

Dear Richard,

It turns out that this is not a harmful error. It was a left-over from copy-pasting an old LO code and not correctly updating it at NLO. For your process there is no harm in the problem "Error BW setting: not supported at NLO". Hence, editing the 'SubProcesses/driver_mintMC.f' file and removing the line containing the 'stop 1' (just after the line containing the written error message, line 730 or so) is perfectly fine.

I'll update the code accordingly so that this error message no longer appears.

Thanks for posting this error message!

Best,
Rikkert

Revision history for this message
Richard Ruiz (rruiz) said :
#4

Hi Rikkert,

Thanks for the clarification. Out of curiosity, why does this impact WWW and not, say, ttW? Also, will this update be pushed immediately or rolled out with the next MG update?

best,
Richard

Revision history for this message
Rikkert Frederix (frederix) said :
#5

Dear Richard,

It's related to having processes with diagrams that contain 4-point vertices and identical particle symmetry factors.
The fix will be part of the next MG5_aMC update --- probably 2.5.6.

Best,
Rikkert

Revision history for this message
Richard Ruiz (rruiz) said :
#6

Hi Rikkert,

Thanks for the quick responses and details. Things seem to be running successfully after commenting out the "STOP" flag. Thanks!

best,
richard