# This is the README file for the HC_NLO_X0 UFO
# Authors: F. Demartin, M. Zaro
#   email: federico.demartin@uclouvain.be
# Model version: 1.2


___________________
***  CHANGELOG  ***

1.2 (2015.06.02) 
    - Fixed a conflict with MadLoop for loop-induced processes
    - Included instructions for single top + higgs production

1.1 (2014.04.03) 
    - Modified loop_particles attributes to be compliant with the new 
      conventions of UFO@NLO, effective in MG5_aMC starting from v2.1.1.
      In particular, use PDG code instead of particle name.
      Changes affect the following files: object_library.py, particles.py.
      Other minor changes in some files: __init__.py, CT_parameters, 
      paramcard_heft.dat, restrict_heft.dat.

1.0 (2014.01.27)
    - Release

___________________________
***  IMPORTANT REMARKS  ***

- Use with MG5_aMC 2.1.1 or later
- Only for single X0 production and decay
- 4F scheme with 'HC_NLO_X0' and 'HC_NLO_X0-4Fnoyb'
     p,j = g u c d s u~ c~ d~ s~ 
- 5F scheme with 'HC_NLO_X0-no_b_mass' and 'HC_NLO_X0-heft'
     p,j = g u c d s b u~ c~ d~ s~ b~
- Find below the correct instructions to generate a process

____________________________________________
***  INSTRUCTIONS TO GENERATE A PROCESS  ***

[1] GLUON FUSION + 0,1,2 JETS (GF) at NLO-QCD [arXiv:1306.6464, arXiv:1407.5089]

> import model HC_NLO_X0-heft
> generate p p > x0 (j ...) / t [QCD]

where '/ t' filters out diagrams with top loops, that are already
accounted for by the X0-gluons effective couplings in the limit Mtop->inf.


[2] WEAK VECTOR BOSON FUSION (VBF) at NLO-QCD [arXiv:1311.1829]

> import model HC_NLO_X0(-no_b_mass)   
> generate p p > x0 j j $$ w+ w- z / a [QCD]

where '$$ w+ w- z' removes diagrams with W/Z in the s-channel, which 
are included in VH production, and '/ a' removes diagrams with photons.

Before you 'launch' the process, exit mg5_aMC, go to the output directory and 
1) comment with a hash '#' the line
  tests.append('check_poles')
inside the file
  bin/internal/amcatnlo_run_interface.py
2) set to -1 the parameters 
  'IRPoleCheckThreshold' and 'PrecisionVirtualAtRunTime'
in the file
   Cards/FKSparams.dat .


[3] VECTOR BOSON ASSOCIATED PRODUCTION (VH) at NLO-QCD [arXiv:1311.1829]

> import model HC_NLO_X0(-no_b_mass)  
> generate p p > x0 l+ vl [QCD] 
> add process p p > x0 l- vl~ [QCD] 
> add process p p > x0 l+ l- / a [QCD] 

where '/ a' removes diagrams with photons.


[4] TOP PAIR ASSOCIATED PRODUCTION (ttH) at NLO-QCD [arXiv:1407.5089]

> import model HC_NLO_X0(-no_b_mass)  
> generate p p > x0 t t~ [QCD]    


[5] SINGLE TOP ASSOCIATED PRODUCTION (tH) at NLO-QCD [arXiv:1504.00611]

t-channel, 4-flavour scheme:
> import model HC_NLO_X0-4Fnoyb
> generate p p > x0 t b~ j $$ w+ w- [QCD]
> add process p p > x0 t~ b j $$ w+ w- [QCD] 

t-channel, 5-flavour scheme:
> import model HC_NLO_X0-no_b_mass
> generate p p > x0 t j $$ w+ w- [QCD]
> add process p p > x0 t~ j $$ w+ w- [QCD] 

s-channel:
> import model HC_NLO_X0(-no_b_mass)
> generate p p > w+ > x0 t b~ [QCD]
> add process p p > w- > x0 t~ b [QCD]


__________________________
***  ACKNOWLEDGEMENTS  ***

This UFO model contains parts of the following models:
- loop_sm   by V. Hirschi
- heft   by N. Christensen, C. Duhr;
- HC (HiggsCharacterisation)   by P. de Aquino, K. Mawatari.

The R2 counterterms for the H-gluons vertices have firstly
been computed by B. J. Page and R. Pittau [arXiv:1307.6142].

F.D. thanks the following people for their support during the
implementation and validation of this model:
C. Degrande, R. Frederix, V. Hirschi, F. Maltoni, O. Mattelaer, 
K. Mawatari, B. J. Page, T. Peraro, R. Pittau, M. Zaro.