Light Kaluza-Klein states in Randall-Sundrum models with custodial SU(2).
We consider Randall-Sundrum scenarios based on SU(2){sub L} x SU(2){sub R} and a discrete parity exchanging L with R. The custodial and parity symmetries can be used to make the tree level contribution to the T parameter and the anomalous couplings of the bottom quark to the Z very small. We show that the resulting quantum numbers typically induce a negative T parameter at one loop that, together with the positive value of the S parameter, restrict considerably these models. There are nevertheless regions of parameter space that successfully reproduce the fit to electroweak precision observables with light Kaluza-Klein excitations accessible at colliders. We consider models of gauge-Higgs unification that implement the custodial and parity symmetries and find that the electroweak data singles out a very well defined region in parameter space. In this region one typically finds light gauge boson Kaluza-Klein excitations as well as light Su(2){sub L}singlet, and sometimes also doublet, fermionic states, that mix with the top quark, and that may yield interesting signatures at future colliders.
- Research Organization:
- Argonne National Laboratory (ANL)
- Sponsoring Organization:
- SC
- DOE Contract Number:
- AC02-06CH11357
- OSTI ID:
- 939069
- Report Number(s):
- ANL-HEP-PR-06-53
- Journal Information:
- Nucl. Phys. B, Journal Name: Nucl. Phys. B Journal Issue: Dec. 2006 Vol. 759
- Country of Publication:
- United States
- Language:
- ENGLISH
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