Gravitational Waves from Walking Technicolor. (arXiv:1811.05670v1 [hep-ph])

Gravitational Waves from Walking Technicolor. (arXiv:1811.05670v1 [hep-ph])
<a href="http://arxiv.org/find/hep-ph/1/au:+Miura_K/0/1/0/all/0/1">Kohtaroh Miura</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Ohki_H/0/1/0/all/0/1">Hiroshi Ohki</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Otani_S/0/1/0/all/0/1">Saeko Otani</a>, <a href="http://arxiv.org/find/hep-ph/1/au:+Yamawaki_K/0/1/0/all/0/1">Koichi Yamawaki</a>

We study gravitational waves from the first-order electroweak phase
transition in the $SU(N_c)$ gauge theory with $N_f/N_cgg 1$ (“large $N_f$
QCD”) as a candidate for the walking technicolor, which is modeled by the
$U(N_f)times U(N_f)$ linear sigma model with classical scale symmetry (without
mass term), particularly for $N_f=8$ (“one-family model”). This model exhibits
spontaneous breaking of the scale symmetry as well as the $U(N_f)times U(N_f)$
radiatively through the Coleman-Weinberg mechanism $grave{a}$ la
Gildener-Weinberg, thus giving rise to a light pseudo dilaton (techni-dilaton)
to be identified with the 125 GeV Higgs. This model possess a strong
first-order electroweak phase transition due to the resultant Coleman-Weinberg
type potential. We estimate the bubble nucleation that exhibits an ultra
supercooling and then the signal for a stochastic gravitational wave produced
via the strong first-order electroweak phase transition. We show that the
amplitude can be reached to the expected sensitivities of the LISA.

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