Changes between Initial Version and Version 1 of Offshell_interference_effects

Timestamp:

Jul 17, 2015, 11:53:03 AM (9 years ago)

Author:

Benoît Hespel

Comment:

--

Offshell_interference_effects

@@ +1 @@
+= Offshell interference effects =
+
+This page describes step by step how to get the interference between signal and background for the WW > vlqq' and ZZ fully leptonic decay in the SM and some extended model within MG_aMC@NLO
+
+'''Authors :  Benoît Hespel [https://cp3.irmp.ucl.ac.be/Members/bhespel email] and Eleni Vryonidou [https://cp3.irmp.ucl.ac.be/Members/evryonidou email] '''
+
+----
+
+== SM ==
+
+You can download a modified version of the loop_sm model ([attachment:loop_sm_modif.tar.gz loop_sm_modif]) where we made simple changes in the couplings orders to be able to get the pieces (signal, background, interference) separately.
+
+===  ZZ > ll l'l' ===
+
+After you imported it inside the MG_2.3.1 loop_induced version, use the following syntax to get the different pieces for the ZZ > e+ e- µ+ µ- for example:
+
+'''Signal''' :  
+{{{
+generate g g > e+ e- mu+ mu- / e+ e- mu+ mu- [QCD] NP^2==2
+}}}
+
+'''Interference''' : 
+{{{
+generate g g > e+ e- mu+ mu- / e+ e- mu+ mu- [QCD] NP^2==1
+}}}
+
+'''Total''' : 
+{{{
+generate g g > e+ e- mu+ mu- / e+ e- mu+ mu- [QCD] NP=1
+}}}
+
+'''Background''' : 
+{{{
+generate g g > e+ e- mu+ mu- / e+ e- mu+ mu- [QCD] NP=0
+}}}
+
+
+----
+
+=== WW > vl qq' ===
+
+For the WW > ve e+ d u~ process for example, use:
+
+'''Signal''': 
+{{{
+generate g g > e+ ve d u~ / e+ e- d u~ [QCD] NP^2==2
+}}}
+
+'''Interference''': 
+{{{
+generate g g > e+ ve d u~ / e+ e- d u~ [QCD] NP^2==1
+}}}
+
+'''Total''': 
+{{{
+generate g g > e+ ve d u~ / e+ e- d u~ [QCD] NP=1
+}}}
+
+'''Background''': 
+{{{
+generate g g > e+ ve d u~ / e+ e- d u~ [QCD] NP=0
+}}}
+
+----
+
+== Additional heavy scalar ==
+
+Then we extended the scalar sector of the SM by adding one additional particle called Y^0^. Via 2 parameters in the param_card, this particle can be set to be either a scalar (gSu33=1 & gPu33=0), a pseudoscalar (gSu33=0 & gPu33=1) or a mixed state (gSu33=x & gPu33=1-x). 
+
+The model can be downloaded here [attachment:Scalar_simp_NLO_UFO_modif.tar.gz Scalar_simp_NLO_UFO] and allows you to get the different pieces separately via the same commands as before.