= Dark Matter Gauge invariant simplified model with CP-even Spin-0 s-channel mediator =
== Authors ==
Giorgio Busoni (University of Melbourne)
email: giorgio.busoni@unimelb.edu.au

== Description of the model ==
This is a gauge-invariant simplified model for dark matter with a CP-even spin-0 mediator exchanged in the s-channel. Dark matter is taken to be a Dirac Fermion.
For more details: [[BR]]
 * [arXiv:1612.03475]: Nicole F. Bell, Giorgio Busoni, Isaac W. Sanderson, "Self-consistent Dark Matter Simplified Models with an s-channel scalar mediator"

== Model files ==
 * S2HDM.fr: main model file for spin-0 mediators.
 * cabibbo.rst, Massless4f.rst, Massless5f.rst: restriction files.
 * S2HDM.nb: this is an example Mathematica notebook that loads the model, checks consistency, calculates the Feynman rules and outputs the model in various formats.
 * unitarity.m: additional mathematica file loaded by the mathematica notebook, that checks unitarity, perturbativity and stability of potential
 * S2HDM_X.nlo files: NLOCT output, necessary to generate NLO UFO

== Download ==
 * Full package
 * UFO Type I (5FS)
 * UFO Type II (5FS)
 * UFO Aligned (5FS)
 * CALCHEP Aligned


== Version updates ==
v1.0 release version [[BR]]
v0.7 prerelease version

== Sample commands for MadGraph5_aMC@NLO ==
The UFO provided together with the feynrules model file was generated for four flavour scheme (4FS) calculations. To perform 5FS ones, you need to generate a new UFO by loading massless_5f restriction file instead of massless_4f.

Below we give the MadGraph syntax used to generate various mono-X signals

=== MONO-JET ===


{{{
generate p p > j ~xd ~xd~ [QCD]
}}}


Massive top and bottom quarks. 4FS calculation.
This is LO as there are no tree level diagrams in this scheme.

=== MONO-H ===


{{{
generate p p > h ~xd ~xd~ [QCD]
}}}


Same notes as above.

=== MONO-Z ===


{{{
generate p p > z ~xd ~xd~ [QCD]
}}}


Same notes as above.

=== MONO-W ===

WARNING: needs 5FS UFO!


{{{
generate p p > w+ ~xd ~xd~ [QCD]
}}}


This has not been tested. 
This is LO as there are no tree level diagrams in this scheme.

=== TT+MET (tree level) ===


{{{
generate p p > t t~ ~xd ~xd~
}}}


Massive top and bottom quarks. 4FS calculation.

=== BB+MET (tree level) ===


{{{
generate p p > b b~ ~xd ~xd~
}}}


Massive top and bottom quarks. 4FS calculation.

=== TT+MET (NLO) ===

Not working yet. However you can generate


{{{
generate p p > t t~ S1 [QCD]

generate p p > t t~ S2 [QCD]
}}}


Massive top and bottom quarks. 4FS calculation.
This is NLO accurate result including both top and bottom loops.

=== BB+MET (NLO) ===

same as above.

=== DI-JET+MET ===

WARNING: to make 5FS you need to output a new UFO with the right restrictions


{{{
generate p p > j j ~xd ~xd~ [QCD]
}}}


Massive top and bottom quarks. 4FS calculation.
This is LO as there are no tree level diagrams in this scheme.

To use 5FS, you need to generate a new UFO output by loading massless_5f restriction file instead of massless_4f.