MadGraph5_aMC@NLO

The ww>h process in muon collider is ending up with an error

Asked by Navneeth C

Whenever I try to generate the process w+ w- > h at the muon collider, the run is getting terminated with the following error and I am unable to find out the crossection. I am still in the learning phase of MadGraph, so pardon me if I did something wrong in the commands

the error:
Error when reading /home/navneeth/Downloads/MG5_aMC_v3.5.3/MG5_aMC_v3_5_3/op/SubProcesses/P1_wpwm_h/G1/results.dat
Command "generate_events run_01" interrupted with error:
Exception : Reported error: End code 1.0
  Full associated log:
  Process in group number 1
  A PDF is used, so alpha_s(MZ) is going to be modified
  Old value of alpha_s from param_card: 0.11799999999999999
  New value of alpha_s from PDF eva : 0.11799999999999999
  Define smin to 15625.000000000000
  *****************************************************
  * MadGraph/MadEvent *
  * -------------------------------- *
  * http://madgraph.hep.uiuc.edu *
  * http://madgraph.phys.ucl.ac.be *
  * http://madgraph.roma2.infn.it *
  * -------------------------------- *
  * *
  * PARAMETER AND COUPLING VALUES *
  * *
  *****************************************************

   External Params
   ---------------------------------

  mdl_MB = 4.7000000000000002
  mdl_MT = 173.00000000000000
  mdl_MTA = 1.7769999999999999
  mdl_MZ = 91.188000000000002
  mdl_MH = 125.00000000000000
  aEWM1 = 132.50700000000001
  mdl_Gf = 1.1663900000000000E-005
  aS = 0.11799999999999999
  mdl_ymb = 4.7000000000000002
  mdl_ymt = 173.00000000000000
  mdl_ymtau = 1.7769999999999999
  mdl_WT = 1.4915000000000000
  mdl_WZ = 2.4414039999999999
  mdl_WW = 2.0476000000000001
  mdl_WH = 6.3823389999999999E-003
   Internal Params
   ---------------------------------

  mdl_conjg__CKM1x1 = 1.0000000000000000
  mdl_CKM3x3 = 1.0000000000000000
  mdl_conjg__CKM3x3 = 1.0000000000000000
  mdl_complexi = (0.0000000000000000,1.0000000000000000)
  mdl_MZ__exp__2 = 8315.2513440000002
  mdl_MZ__exp__4 = 69143404.913893804
  mdl_sqrt__2 = 1.4142135623730951
  mdl_MH__exp__2 = 15625.000000000000
  mdl_aEW = 7.5467711139788835E-003
  mdl_MW = 80.419002445756163
  mdl_sqrt__aEW = 8.6872153846781555E-002
  mdl_ee = 0.30795376724436879
  mdl_MW__exp__2 = 6467.2159543705357
  mdl_sw2 = 0.22224648578577766
  mdl_cw = 0.88190334743339216
  mdl_sqrt__sw2 = 0.47143025548407230
  mdl_sw = 0.47143025548407230
  mdl_g1 = 0.34919219678733299
  mdl_gw = 0.65323293034757990
  mdl_vev = 246.21845810181637
  mdl_vev__exp__2 = 60623.529110035903
  mdl_lam = 0.12886910601690263
  mdl_yb = 2.6995554250465490E-002
  mdl_yt = 0.99366614581500623
  mdl_ytau = 1.0206617000654717E-002
  mdl_muH = 88.388347648318430
  mdl_I1x33 = (2.69955542504654901E-002,0.0000000000000000)
  mdl_I2x33 = (0.99366614581500623,0.0000000000000000)
  mdl_I3x33 = (0.99366614581500623,0.0000000000000000)
  mdl_I4x33 = (2.69955542504654901E-002,0.0000000000000000)
  mdl_ee__exp__2 = 9.4835522759998875E-002
  mdl_sw__exp__2 = 0.22224648578577769
  mdl_cw__exp__2 = 0.77775351421422245
   Internal Params evaluated point by point
   ----------------------------------------

  mdl_sqrt__aS = 0.34351128074635334
  mdl_G__exp__2 = 1.4828317324943823
   Couplings of sm
   ---------------------------------

         GC_72 = 0.00000E+00 0.52532E+02

  Collider parameters:
  --------------------

  Running at m+m- machine @ 30000.000000000000 GeV
  PDF set = eva
  alpha_s(Mz)= 0.1180 running at 2 loops.
  alpha_s(Mz)= 0.1180 running at 2 loops.
  Renormalization scale set on event-by-event basis
  Factorization scales fixed @ 91.188000000000002 91.188000000000002

  getting user params
 Enter number of events and max and min iterations:
  Number of events and iterations 2000 5 3
 Enter desired fractional accuracy:
  Desired fractional accuracy: 0.10000000000000001
 Enter 0 for fixed, 2 for adjustable grid:
 Suppress amplitude (0 no, 1 yes)?
  Using suppressed amplitude.
 Exact helicity sum (0 yes, n = number/event)?
  Monte-Carlo over helicities

  ********************************************
  * You are using the DiscreteSampler module *
  * part of the MG5_aMC framework *
  * Author: Valentin Hirschi *
  ********************************************

 Enter Configuration Number:
 Running Configuration Number: 1
  Not subdividing B.W.
  Attempting mappinvarients 1 3
  Determine nb_t
  T-channel found: 0
  Completed mapping 3
  about to integrate 1 2000 5 3 1 1
  Using non-zero grid deformation.
   1 dimensions 2000 events 2 invarients 5 iterations 1 config(s), (0.99)
  Using h-tuple random number sequence.
  Error opening grid
  Using Uniform Grid! 12
  Using uniform alpha 1.0000000000000000
  Grid defined OK
  Masses: 0.804E+02 0.804E+02 0.125E+03
  Set CM energy to 30000.00
  Mapping Graph 1 to config 1
  Determine nb_t
  T-channel found: 0
  Transforming s_hat 1/s 1 1.7361111111111114E-005 15625.000000000000 899999999.99999988
 Using random seed offsets 1 : 1
   with seed 24
  Ranmar initialization seeds 31059 9398
   Particle 3
       Et > 0.0
        E > 0.0
      Eta < -1.0
    xqcut: 0.0
  alpha_s for scale 125.00000000000001 is 0.11264791130998673
  Iteration 1 Mean: NaN Abs mean: NaN Fluctuation: NaN -0.100E+01 100.0%
   1 NaN NaN +- NaN NaN
  Writing out events NaN NaN
  DiscreteSampler:: Error, no point could be picked with random variable 0.2365935444831848 using upper bound found of NaN.
 Note: The following floating-point exceptions are signalling: IEEE_INVALID_FLAG
 STOP 1

 ls status:
 input_app.txt
 run1_app.log

Please report this bug on https://bugs.launchpad.net/mg5amcnlo
More information is found in '/home/navneeth/Downloads/MG5_aMC_v3.5.3/MG5_aMC_v3_5_3/op/run_01_tag_1_debug.log'.
Please attach this file to your report.

Question information

Language:
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Status:
Solved
For:
MadGraph5_aMC@NLO Edit question
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Solved by:
Sihyun Jeon
Solved:
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Last reply:
Revision history for this message
Olivier Mattelaer (olivier-mattelaer) said : 		#1

Hi,

It does not make sense to ask for
"ww>h"
at muon collider, indeed the EWA approximation only work of sqrts>1TeV and the Higgs mass is much smaller than such limit.

Cheers,

Olivier

Revision history for this message
Navneeth C (navneethc2001) said (last edit ): 		#2

Thanks a lot for the prompt response

So, these are the commands i gave -

generate w+ w- > h
output muoncollider
launch muoncollider

then i edited the runcard

set ebeam1 1500
set ebeam2 1500
set lpp1 -4
set lpp2 4

Is there anything to add or what may be the issue that is causing those errors?
My goal is to obtain SM Higgs Boson production cross sections at muon collider for various energies. So for that what are all the commands should I give and is there any models that I should import, like the heft?

WW -> H
ZZ -> H

Cross sections of these are required

Revision history for this message
Olivier Mattelaer (olivier-mattelaer) said : 		#3

Hi,

Your process is kinematically impossible:
Indeed, let assume that each muon beam give you a "W" at rest (the smallest amount of energy possible)
in that case the center of mass energy is 2*MW which is too large to produce a Higgs on-shell (which should be MH< a*MW).

Independently of the fact that such process is kinematically possible (or not), in order to use the PDF approximation of the "W", you need that sqrts (not sqrt) being at least one TeV (otherwise the approximation does not make sense). In your process sqrts=mh=125 which is too small (and this does not depend of the energy of your collider).

So you need to change your process, maybe to something like
mu+ mu- > vm vm~ h
(likely with lpp set to 0)

Cheers,

Olivier

Revision history for this message
Navneeth C (navneethc2001) said (last edit ): 		#4

Thanks for the explanation. mu+ mu- > vm vm~ h works!

Can you please share the commands for the below listed processes at the muon collider? ( I need to find out cross section for various energies)

σ(fb):WW→H
 ZZ→H
 WW→HH
 ZZ→HH
 WW→ZH
 WW→t¯ tH
 WW→Z
 WW→ZZ

Revision history for this message
Navneeth C (navneethc2001) said : 		#5

Hi, can you please guide me through this? It's for my masters thesis.

Revision history for this message
Best Sihyun Jeon (shjeon) said : 		#6

you should draw the feynman diagrams yourself and see what your initial states are (in this case though mu+ mu-) and what your final states are and give those to madgraph syntaxes.

You already have
WW->H : mu+ mu- > vm vm~ h

as a pointer i can give you some examples but obviously i didn't run them myself so it's up to you to check whether the diagrams you get are really the ones you intended to have (look at ps files in your <Output>/SubProcesses/PX_XX_XXXX directories, X are the initial and final state particle dependent)

ZZ->H : mu+ mu- > mu+ mu- h
WW->ZZ : mu+ mu- > vm vm~ z z

Revision history for this message
Navneeth C (navneethc2001) said : 		#7

Thanks Sihyun Jeon, that solved my question.