Testing the custodial symmetry in the Higgs sector of the Georgi-Machacek model
Journal
JHEP
Journal Volume
01
Pages
026
Date Issued
2012-11
Author(s)
Yagyu, Kei
Abstract
We study how the custodial symmetry in the Higgs sector of the Georgi-Machacek (GM) model can be tested at the LHC. As the minimal extension of the Higgs triplet model, in which tiny neutrino masses are generated via the Type-II Seesaw Mechanism, the GM model keeps the electroweak ρ parameter at unity at tree level. In the GM model, there are 5-plet (H 5), 3-plet (H 3) and singlet (H 1) Higgs bosons under the classification of the custodial SU(2) V symmetry, in addition to the standard model-like Higgs boson (h). These new Higgs bosons have the following characteristic features at the tree level: (1) the masses of the Higgs bosons belonging to the same SU(2) V multiplet are degenerate; and (2) H 5 and H 1 couple to the electroweak gauge bosons but not SM quarks, whereas H 3 couples to the quarks but not the gauge bosons. We find that the H 5 production from the weak vector boson fusion process and the Drell-Yan process associated with H 3 are useful in testing the custodial symmetry of the Higgs sector at the LHC. In addition, these processes can also be used to discriminate from other models that contain singly-charged Higgs bosons and extra neutral Higgs bosons. We also investigate a possible enhancement in the h → γγ as well as h → Zγ decays. © 2013 SISSA, Trieste, Italy.
Type
journal article