@misc{10481/72309,
year = {2021},
month = {12},
url = {http://hdl.handle.net/10481/72309},
abstract = {We inspect the Littlest Higgs model with T-parity, based on a global symmetry
SU(5) spontaneously broken to SO(5), in order to elucidate the pathologies it presents due to
the non-trivial interplay between the gauge invariance associated to the heavy modes and the
discrete T-parity symmetry. In particular, the usual Yukawa Lagrangian responsible for providing
masses to the heavy ‘mirror’ fermions is not gauge invariant. This is because it contains
an SO(5) quintuplet of right-handed fermions that transforms nonlinearly under SU(5), hence
involving in general all SO(5) generators when a gauge transformation is performed and not
only those associated to its gauge subgroup. Part of the solution to this problem consists of
completing the right-handed fermion quintuplet with T-odd ‘mirror partners’ and a gauge
singlet, what has been previously suggested for other purposes. Furthermore, we find that the
singlet must be T-even, the global symmetry group must be enlarged, an additional nonlinear
sigma field should be introduced to parametrize the spontaneous symmetry breaking and new
extra fermionic degrees of freedom are required to give amass to all fermions in an economic
way while preserving gauge invariance. Finally, we derive the Coleman–Weinberg potential
for the Goldstone fields using the background field method.},
organization = {Spanish Government	FPA2016-78220-C3	
PID2019-107844GBC21/ AEI/10.13039/501100011033},
organization = {Junta de Andalucia	FQM 101	
SOMM17/6104/UGR	
P18-FR-1962	
P18-FR-5057},
publisher = {Springer},
title = {A new and gauge-invariant littlest Higgs model with T-parity},
doi = {10.1140/epjp/s13360-021-02222-0},
author = {Illana Calero, José Ignacio and Pérez Poyatos, José María},
}