Version 3 (modified by druekeel, 19 months ago) (diff) 

A Coloron Model
Authors
 Elizabeth Drueke (Michigan State University)
 Joseph Nutter (Michigan State University)
 Reinhard Schwienhorst (Michigan State University)
 Natascia Vignaroli (Michigan State University)
 Devin G. E. Walker (SLAC National Accelerator Laboratory)
 JiangHao Yu (The University of Texas at Austin)
Description of the Model
The
breaking induced by the expectation value of the
scalar field Phi generates coloroctet and colorsinglet scalars. The most general renormalizable potential for Phi is:
where
and where, without loss of generality, one can choose mu > 0. Assuming
Phi acquires a (positive) diagonal expectation value:
The Phi expansion around the vacuum gives:
where
are singlets under SU(3)_C Additionally,
are the NambuGoldstone bosons associated with the colorsymmetry breaking, which will be eaten by the
color octets.
$G_H$ can be produced in pairs through its interactions with gluons:
or it can be produced singly via gluongluon fusion. This occurs at oneloop order through the cubic interaction
which arises from the
term in the potential; where
is the SU(3) totally symmetric tensor. The single production of GH can be described by the effective coupling
with
Note that single production is suppressed by a factor
which is an accidental suppression factor coming from the loop. Above the threshold for decays into a single top quark, GH has two main decay modes: the decay into gluons, which occurs at looplevel similar to single coloron production, and the flavorviolating decay into tc. The corresponding rates are:
We set u=mu (the stability of the potential forbids mu>u); and consider for simplicity the set of
values that give a 50% GH decay into tc and 50% into gg. GH is a very narrow resonance, with a width of the order of 10^{4 GeV. }
Various Feynman Diagrams for GH processes discussed in 1409.7607v2 are shown below:
Model Files
 proc_card: for generation of 500 GeV coloron (place in Cards/)
 run_card: for generation of 500 GeV coloron (place in Cards/)
 Octettcgg: the model
Generation specifics
In 1409.7607v2, the samples were generated with the mass as the scale, dsqrt_q2fact1, and dsqrt_q2fact2 in the run_card. These samples were also generated without the preincluded MadGraph cuts as demonstrated in the run_card.dat for 500 GeV mass included above. The specific generations run were
p p > GH, GH > b c~ l+ vl @1 GHT=1 QED=2 p p > GH, GH > b~ c l vl~ @2 GHT=1 QED=2
Specific masses can be generated using the appropriate model from the Octettcgg zip file.
Attachments

Coloron.png
(2.0 KB) 
added by druekeel 19 months ago.
Feynman Diagram 1

ColoronDouble1.png
(2.6 KB) 
added by druekeel 19 months ago.
Feynman Diagram 2

ColoronDouble2.png
(2.7 KB) 
added by druekeel 19 months ago.
Feynman Diagram 3

Colorong.png
(2.1 KB) 
added by druekeel 19 months ago.
Feynman Diagram 4

Colorong2.png
(2.5 KB) 
added by druekeel 19 months ago.
Feynman Diagram 5

proc_card_mg5.dat
(2.4 KB) 
added by druekeel 19 months ago.
process card for a 500 GeV mass coloron

run_card.dat
(13.8 KB) 
added by druekeel 19 months ago.
run card for a 500 GeV mass coloron

Octettcggnew.zip
(163.9 KB) 
added by druekeel 19 months ago.
model