Parameters used in MadLoop computations

Hi James,

> 1) Have MG print out a list of paramters that it is using in the calculation so I can be sure it is doing what I expect

I did the following
> generate p p > h [QCD]
> output XXX

then leave MG5
> cd XXX/SubProcesses/P0_gg_h
> make check
> ./check

and I have the following output:

> AO2PI= 1.8780283284843650E-002
> *****************************************************
> * MadGraph/MadEvent *
> * -------------------------------- *
> * http://madgraph.hep.uiuc.edu *
> * http://madgraph.phys.ucl.ac.be *
> * http://madgraph.roma2.infn.it *
> * -------------------------------- *
> * *
> * PARAMETER AND COUPLING VALUES *
> * *
> *****************************************************
>
> External Params
> ---------------------------------
>
> MU_R = 91.188000000000002
> aEWM1 = 132.50700000000001
> mdl_Gf = 1.1663900000000000E-005
> aS = 0.11799999999999999
> mdl_ymb = 4.7000000000000002
> mdl_ymt = 173.00000000000000
> mdl_ymtau = 1.7769999999999999
> mdl_MT = 173.00000000000000
> mdl_MB = 4.7000000000000002
> mdl_MZ = 91.188000000000002
> mdl_MH = 125.00000000000000
> mdl_MTA = 1.7769999999999999
> mdl_WT = 1.4915000000000000
> mdl_WZ = 2.4414039999999999
> mdl_WW = 2.0476000000000001
> mdl_WH = 6.3823389999999999E-003
> Internal Params
> ---------------------------------
>
> mdl_conjg__CKM3x3 = 1.0000000000000000
> mdl_CKM22 = 1.0000000000000000
> mdl_lhv = 1.0000000000000000
> mdl_CKM3x3 = 1.0000000000000000
> mdl_conjg__CKM22 = 1.0000000000000000
> mdl_conjg__CKM33 = 1.0000000000000000
> mdl_Ncol = 3.0000000000000000
> mdl_CA = 3.0000000000000000
> mdl_TF = 0.50000000000000000
> mdl_CF = 1.3333333333333333
> 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_Ncol__exp__2 = 9.0000000000000000
> mdl_MB__exp__2 = 22.090000000000003
> mdl_MT__exp__2 = 29929.000000000000
> 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_v = 246.21845810181637
> mdl_v__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_AxialZUp = -0.18517701861793787
> mdl_AxialZDown = 0.18517701861793787
> mdl_VectorZUp = 7.5430507588273299E-002
> mdl_VectorZDown = -0.13030376310310560
> mdl_VectorAUp = 0.20530251149624587
> mdl_VectorADown = -0.10265125574812294
> mdl_VectorWmDxU = 0.23095271737156670
> mdl_AxialWmDxU = -0.23095271737156670
> mdl_VectorWpUxD = 0.23095271737156670
> mdl_AxialWpUxD = -0.23095271737156670
> mdl_I1x33 = ( 2.6995554250465490E-002, 0.0000000000000000 )
> mdl_I2x33 = ( 0.99366614581500623 , 0.0000000000000000 )
> mdl_I3x33 = ( 0.99366614581500623 , 0.0000000000000000 )
> mdl_I4x33 = ( 2.6995554250465490E-002, 0.0000000000000000 )
> mdl_Vector_tbGp = (-0.96667059156454072 , 0.0000000000000000 )
> mdl_Axial_tbGp = ( -1.0206617000654716 , -0.0000000000000000 )
> mdl_Vector_tbGm = ( 0.96667059156454072 , 0.0000000000000000 )
> mdl_Axial_tbGm = ( -1.0206617000654716 , -0.0000000000000000 )
> mdl_gw__exp__2 = 0.42671326129048615
> mdl_cw__exp__2 = 0.77775351421422245
> mdl_ee__exp__2 = 9.4835522759998875E-002
> mdl_sw__exp__2 = 0.22224648578577769
> mdl_yb__exp__2 = 7.2875994928982540E-004
> mdl_yt__exp__2 = 0.98737240933884918
> Internal Params evaluated point by point
> ----------------------------------------
>
> mdl_sqrt__aS = 0.34351128074635334
> mdl_G__exp__4 = 2.1987899468922913
> mdl_G__exp__2 = 1.4828317324943823
> mdl_GWcft_UV_b_1EPS_ = -3.1300472141406080E-003
> mdl_GWcft_UV_t_1EPS_ = -3.1300472141406080E-003
> mdl_bWcft_UV_1EPS_ = -1.8780283284843650E-002
> mdl_tWcft_UV_1EPS_ = -1.8780283284843650E-002
> mdl_G__exp__3 = 1.8056676068262196
> mdl_MU_R__exp__2 = 8315.2513440000002
> mdl_GWcft_UV_b_FIN_ = -1.8563438626678915E-002
> mdl_GWcft_UV_t_FIN_ = 4.0087659331150384E-003
> mdl_bWcft_UV_FIN_ = -0.13642100947319838
> mdl_tWcft_UV_FIN_ = -9.8778211443463623E-004
> Couplings of loop_sm
> ---------------------------------
>
> R2_GGHb = 0.00000E+00 -0.33698E-02
> R2_GGHt = 0.00000E+00 -0.45657E+01
> GC_5 = 0.00000E+00 0.12177E+01
> GC_33 = -0.00000E+00 -0.19089E-01
> GC_37 = -0.00000E+00 -0.70263E+00

(plus a lot of stuff useless for this email.

The function responsible for that print on the screen is “printout"

It indicates the value of parameter separated in multiple categories
1) External Params. That’s the entry of the param_card, the value that you are allowed to modify.

2) Internal parameter: parameter where the value is fixed by the model.
either via an analytical formula or via a fix value.
The later typically occur if we apply some assumptions on the model to simplify it (in order to have more efficient code.) one example of that is the “mdl_CKM3x3” which is force to be one since we have remove from the model all non diagonal CKM coupling.

3) Internal Params evaluated point by point.
Same as two, but the value depends of alphas and is therefore re-computed point-by-point in the phase-space.
Obviously those are only given by analytical formula

4) Couplings of loop_sm

The actual value of the coupling used for each vertex.
The list is here tailored to your process.
The code separated the coupling in two class (like for the internal parameter) but this is not reflected in the display.

> 2) Manually change things like the Higgs vet, or at least be directed to the file that calculates it.

Pointless to stress that you need to deeply understand the model to do something like that.
I have to discourage you of doing it manually in the fortran file (especially for NLO model).
My suggestion, would be that you write your Lagrangian in FR. There you can choose the parametrization that you want and decide which
parameter are external.

If you really want to modify the parameter at the fortran file, here is the file that define all the internal parameter:
Source/MODEL/intparam_definition.inc

Cheers,

Olivier

> On Sep 9, 2016, at 10:53, James Cockburn <email address hidden> wrote:
>
> New question #389099 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/389099
>
> Hi,
>
> I am currently trying to evaluate the matrix elements for the process gu -> gHu with full finite top mass effects. I have managed to create the standalone library and get it running in my own code. However, what I would like to do is a way of checking what all the parameters that go into the evaluation of the matrix element are. For example, there is a param_card where I can change the top mass and Higgs mass (and presumably this is what then gets fed to the calculation) but I can't, for example, see what the value of the Higgs vacuum expectation value is. So I would like to do two things;
>
> 1) Have MG print out a list of paramters that it is using in the calculation so I can be sure it is doing what I expect
> 2) Manually change things like the Higgs vev, or at least be directed to the file that calculates it.
>
> Cheers,
> James
>
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