momentum precision in indirect detection

[Olivier Mattelaer]

Hi,

I am using MadDM for studying DM indirect detection. In my model, there are 3 kinds of CP-even neutral Higgs bosons, and DM can annihilate into a pair of them, as well as other final states.

I was trying to generate gamma-ray spectrum with the 'precise' mode. I found that the gamma-ray spectrum can be successfully generated for mDM > 100 GeV. However, for mDM < 100 GeV, PYTHIA 8 failed to generate the spectrum. The error information in pythia8.log is as follows.

 -------- LHA initialization information ------------

  beam kind energy pdfgrp pdfset
     A 52 97.198 0 247000
     B 52 97.198 0 247000

  Event weighting strategy = -4

  Processes, with strategy-dependent cross section info
  number xsec (pb) xerr (pb) xmax (pb)
    1995 5.4686e+02 8.3103e-01 5.4686e+02

 -------- End LHA initialization information --------
mDM: 9.7198e+01 outdir: ./
 PYTHIA Error in Pythia::check: energy-momentum not conserved
 PYTHIA Error in Pythia::next: check of event revealed problems
 PYTHIA Abort from Pythia::next: parton+hadronLevel failed; giving up
 PYTHIA Warning in TauDecays::decay: unknown correlated tau production, assuming from unpolarized photon
Event generation aborted prematurely, owing to error!

 *------- PYTHIA Event and Cross Section Statistics -------------------------------------------------------------*
 | |
 | Subprocess Code | Number of events | sigma +- delta |
 | | Tried Selected Accepted | (estimated) (mb) |
 | | | |
 |-----------------------------------------------------------------------------------------------------------------|
 | | | |
 | Les Houches User Process(es) 9999 | 10 10 0 | 0.000e+00 0.000e+00 |
 | ... whereof user classification code 1995 | 10 10 0 | |
 | | | |
 | sum | 10 10 0 | 0.000e+00 0.000e+00 |
 | |
 *------- End PYTHIA Event and Cross Section Statistics ----------------------------------------------------------*

 *------- PYTHIA Error and Warning Messages Statistics ----------------------------------------------------------*
 | |
 | times message |
 | |
 | 10 Abort from Pythia::next: parton+hadronLevel failed; giving up |
 | 100 Error in Pythia::check: energy-momentum not conserved |
 | 100 Error in Pythia::next: check of event revealed problems |
 | 1 Error in SigmaTotal::calc: too low energy |
 | 1 Info from SLHAinterface::initSLHA: attempting to set properties |
 | 1 Info from SLHAinterface::initSLHA: No MODSEL found, keeping internal SUSY switched off |
 | 1 Info from SLHAinterface::initSLHA: importing DECAY tables |
 | 1 Info from SLHAinterface::initSLHA: importing MASS entries |
 | 2 Warning in SLHAinterface::initSLHA: ignoring DECAY tables |
 | 1 Warning in SLHAinterface::initSLHA: ignoring MASS entries |
 | 4 Warning in SLHAinterface::initSLHA: ignoring QNUMBERS |
 | 1 Warning in SLHAinterface::initSLHA: massless particle forced stable |
 | 1 Warning in SLHAinterface::initSLHA: using QNUMBERS for id codes < 1000000 may clash with SM. |
 | 10 Warning in TauDecays::decay: unknown correlated tau production, assuming from unpolarized photon |
 | |
 *------- End PYTHIA Error and Warning Messages Statistics ------------------------------------------------------*

Any idea for fixing this?

Thanks for the help!

Best regards,
Zhao-Huan

[Olivier Mattelaer (olivier-mattelaer)]

Can you attach the lhe file that PY8 try to shower?
This will allow me to check what is the precision level on the momenta provided to py8.

Thanks,

Olivier

[Zhao-Huan Yu (yzhxxzxy)]

Hi Olivier,

I have attached the lhe file of my unweighted events.

Thanks,
Zhao-Huan

[Olivier Mattelaer (olivier-mattelaer)]

Hi,

The madgraph check routines does not spot any issue on the events file. By looking at the first event by eye, the energy-momentum conservation are spot on. The mass of the particles are slightly off but I do not think that pythia complains about that (and this is actually very reasonable discrepancy).

So I would think that the issue is internal to pythia, but I would pass this bug report to someone (chiara) more expert than me on the use of pythia for indirect detection. She might know more.

Cheers,

Olivier

[Chiara Arina (carina)]

Hi,

I will try to have a look at what is going on with pythia but I need to reproduce your error. Could you send me the UFO model file and the param_card.dat for the point that makes pythia crushing?
Also could you send me the script with the exact list of command you use in maddm?

thanks

chiara

[Zhao-Huan Yu (yzhxxzxy)]

Hi Chiara,

I have attached the UFO model file, the param_card.dat, and the script.

Thanks,
Zhao-Huan