The topcolor-assisted technicolor (TC2) model predicts several pseudo-scalars called top-pions and at loop level they can induce the FCNC top quark decay t->cgg which is extremely suppressed in the Standard Model (SM). We find that in the allowed parameter
arXiv:0712.????
Top-QuarkFCNCDecayt→cgg
inTopcolor-assistedTechnicolorModel
arXiv:0712.0151v1 [hep-ph] 2 Dec 2007Huan-JunZhangDepartmentofPhysics,HenanNormalUniversity,Xinxiang,Henan453007,ChinaAbstractThetopcolor-assistedtechnicolor(TC2)modelpredictsseveralpseudo-scalarscalledtop-pionsandatloopleveltheycaninducetheFCNCtopquarkdecayt→cggwhichisextremelysuppressedintheStandardModel(SM).We ndthatintheallowedparameterspacetheTC2modelcangreatlyenhancesuchaFCNCdecayandpushthebranchingratioupto10 3,whichismuchlargerthanthepredictionsintheSM(10 9)andintheminimalsupersymmetricmodel(10 4).Wealsocomparetheresultwiththetwo-bodyFCNCdecayt→cgand ndthatthebrachingratiooft→cggisslightlylargerthant→cg.SuchenhancedFCNCtopquarkdecaysmayserveasagoodprobeofTC2modelatthefuturetopquarkfactory.
PACSnumbers:14.65.Ha,12.60.Fr,12.60.Jv