B̄–B Mixing Constrains Topcolor–Assisted Technicolor
نویسندگان
چکیده
We argue that extended technicolor augmented with topcolor requires that all mixing between the third and the first two quark generations resides in the mixing matrix of left–handed down quarks. Then, the B̄d–Bd mixing that occurs in topcolor models constrains the coloron and Z ′ boson masses to be greater than about 5 TeV. This implies fine tuning of the topcolor couplings to better than 1%. [email protected] [email protected] [email protected]
منابع مشابه
Top Decay in Topcolor-Assisted Technicolor
Conventional technicolor models with light charged technipions (π T ) lead to an unacceptably large contribution to t → π T b decay rate. Topcolor-assisted technicolor models also have additional PGBs called top-pions (π t ) which may contribute to this decay. We study the potentially dangerous mixing of charged top-pion and technipions in toy models of ‘natural’ topcolor-assisted technicolor. ...
متن کاملProgress on Symmetry Breaking and Generational Mixing in Topcolor-assisted Technicolor
Topcolor-assisted technicolor provides a dynamical explanation for electroweak and flavor symmetry breaking and for the large mass of the top quark without unnatural fine tuning. I briefly review the basics of topcolor-assisted technicolor, including major constraints and a general approach to satisfying them. The main challenge to topcolor-assisted technicolor is to generate the observed mixin...
متن کاملNatural Topcolor–Assisted Technicolor
We construct a prototype of topcolor–assisted technicolor in which, although both top and bottom quarks acquire some mass from extended technicolor, strong U(1) couplings of technifermions are isospin symmetric and all gauge anomalies vanish. There is a mechanism for mixing between the light and heavy generations and there need be no very light pseudo– Goldstone bosons.
متن کاملTopcolor assisted technicolor models and muon anomalous magnetic moment
We discuss and estimate the contributions of the new particles predicted by topcolor assisted technicolor(TC2) models to the muon anomalous magnetic moment aμ. Our results show that the contributions of Pseudo Goldstone bosons are very small which can be safely ignored. The main contributions come from the ETC gauge boson xμ and topcolor gauge boson Z ′. If we demand that the mass of Z ′ is con...
متن کاملhigh-pT jet at the LHC
In the framework of the topcolor-assisted technicolor (TC2) model, we study production of the neutral top-pion π0 t in association with a high-pT jet at the LHC, which proceeds via the partonic processes gg −→ π0 t g, gq −→ π0 t q, qq̄ −→ π0 t g, gb(b̄) −→ π0 t b(b̄), and bb̄ −→ π0 t g. We find that it is very challenging to detect the neutral top-pion π0 t via the process pp −→ π0 t + jet +X → tt̄+...
متن کامل