Version 9 (modified by druekeel, 2 years ago) (diff)

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# A Kaluza-Klein Gluon Model with FCNC Decay to a Single Top Quark

This model allows for FCNC interactions of the Kaluza-Klein gluon and in particular focuses on the flavor-violating decay of the KKg to a top quark and a charm quark.

## Corresponding Authors

• Elizabeth Drueke (Michigan State University)
• Reinhard Schwienhorst (Michigan State University)
• Natascia Vignaroli (Michigan State University)

## Other Contributors

• Joseph Nutter (Michigan State University)
• Devin G. E. Walker (SLAC National Accelerator Laboratory)
• Jiang-Hao Yu (The University of Texas at Austin)
• R. Sekhar Chivukula (Michigan State University)
• Elizabeth H. Simmons (Michigan State University)

## Description of the Model

Colored vector bosons from new strong dynamics, Kaluza-Klein gluons or KKg’s (G*) in a dual 5D picture, have been searched for mainly in the t-tbar channel. The analysis in 1409.7607v2 analyzes the tc decay as depicted below: The benchmark adopted here is a simple renormalizable model of an extended color gauge sector, which realizes next-to-minimal flavor violation (NMFV). In this model, the third generation quarks couple differently than the light quarks under an extended

color gauge group. The mixing between light and third generation quarks is induced by the interactions of all three generation quarks with a set of new heavy vector-like quarks. Gluon-gluon fusion production is forbidden at tree level by SU(3)_C gauge invariance.

The G* decay widths are:

Additionally, the NMFV flavor structure of the model generates a G* to tc flavor violating decay with rate

where

is the CKM matrix element.

The default value is

which corresponds to a width of about 25% of the KKg mass.

See more details in

## Model Files

• proc_card: for generation of 500 GeV KKg (place in Cards/)
• run_card: for generation of 500 GeV KKg (place in Cards/)
• kkg_FV: the model and parameter cards for specific mass generations

## Generation specifics

In 1409.7607v2, the samples were generated with the KKg mass as the scale, dsqrt_q2fact1, and dsqrt_q2fact2 in the run_card.dat file. These samples were also generated without MadGraph cuts as demonstrated in the run_card.dat file for 500 GeV mass included above. The specific generations run were

p p > kkg > b~ c l- vl~ @1
p p > kkg > b c~ l+ vl @2


To generate the settings for a specific KKg mass, change the param_card.dat in the generation directory to the card of the appropriate mass in the param_cards directory (included as part of the model zip file). It is important to do this immediately before generating events.