TY - JOUR

T1 - A custodial symmetry for Zbb¯

AU - Agashe, Kaustubh

AU - Contino, Roberto

AU - Da Rold, Leandro

AU - Pomarol, Alex

PY - 2006/9/28

Y1 - 2006/9/28

N2 - We show that a subgroup of the custodial symmetry O (3) that protects Δρ from radiative corrections can also protect the Z b over(b, ̄) coupling. This allows one to build models of electroweak symmetry breaking, such as higgsless, little Higgs or 5D composite Higgs models, that are safe from corrections to Z → b over(b, ̄). We show that when this symmetry protects Z b over(b, ̄) it cannot simultaneously protect Z t over(t, ̄) and W t over(b, ̄). Therefore one can expect to measure sizable deviations from the SM predictions of these couplings at future collider experiments. We also show under what circumstances Z bR over(b, ̄)R can receive corrections in the right direction to explain the anomaly in the LEP/SLD forward-backward asymmetry AFBb. © 2006 Elsevier B.V. All rights reserved.

AB - We show that a subgroup of the custodial symmetry O (3) that protects Δρ from radiative corrections can also protect the Z b over(b, ̄) coupling. This allows one to build models of electroweak symmetry breaking, such as higgsless, little Higgs or 5D composite Higgs models, that are safe from corrections to Z → b over(b, ̄). We show that when this symmetry protects Z b over(b, ̄) it cannot simultaneously protect Z t over(t, ̄) and W t over(b, ̄). Therefore one can expect to measure sizable deviations from the SM predictions of these couplings at future collider experiments. We also show under what circumstances Z bR over(b, ̄)R can receive corrections in the right direction to explain the anomaly in the LEP/SLD forward-backward asymmetry AFBb. © 2006 Elsevier B.V. All rights reserved.

U2 - https://doi.org/10.1016/j.physletb.2006.08.005

DO - https://doi.org/10.1016/j.physletb.2006.08.005

M3 - Article

VL - 641

SP - 62

EP - 66

JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

SN - 0370-2693

ER -