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Gravitational waves from chiral phase transition in a conformally extended standard model

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Journal of Cosmology and Astroparticle Physics
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Mayumi Aoki
Mayumi Aoki
Mayumi Aoki
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Jisuke Kubo
Jisuke Kubo
Jisuke Kubo
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Abstract

The gravitational wave (GW) background produced at the cosmological chiral phase transition in a conformal extension of the standard model is studied. To obtain the bounce solution of coupled field equations we implement an iterative method. We find that the corresponding O(3) symmetric Euclidean action S3 divided by the temperature T has a simple behavior near the critical temperature TC: S3/T ∝ (1−T/TC)−γ, which is subsequently used to determine the transition's inverse duration β normalized to the Hubble parameter H. It turns out that β/H ≳ 10³, implying that the sound wave period τsw as an active GW source, too, can be much shorter than the Hubble time. We therefore compute τsw H and use it as the reduction factor for the sound wave contribution. The signal-to-noise ratio (SNR) for Deci-Hertz Interferometer Gravitational Wave Observatory (DECIGO) and Big Bang Observer (BBO) is evaluated, with the result: SNRDECIGO ≲ 1.2 and SNRBBO ≲ 12.0 for five years observation, from which we conclude that the GW signal predicted by the model in the optimistic case could be detected at BBO.
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JCAP04(2020)001
ournal of
Cosmology and Astroparticle Physics
An IOP and SISSA journal
J
Gravitational waves from chiral phase
transition in a conformally extended
standard model
Mayumi Aokiaand Jisuke Kubob,c
aInstitute for Theoretical Physics, Kanazawa University,
Kanazawa 920-1192, Japan
bMax-Planck-Institut f¨ur Physik (Werner-Heisenberg-Institut),
F¨ohringer Ring 6, D-80805 M¨unchen, Germany
cDepartment of Physics, University of Toyama,
3190 Gofuku, Toyama 930-8555, Japan
E-mail: mayumi@hep.s.kanazawa-u.ac.jp,jikubo4@gmail.com
Received October 18, 2019
Revised February 8, 2020
Accepted March 9, 2020
Published April 1, 2020
Abstract. The gravitational wave (GW) background produced at the cosmological chiral
phase transition in a conformal extension of the standard model is studied. To obtain the
bounce solution of coupled field equations we implement an iterative method. We find that
the corresponding O(3) symmetric Euclidean action S3divided by the temperature Thas
a simple behavior near the critical temperature TC:S3/T ∝(1 −T /TC)−γ, which is sub-
sequently used to determine the transition’s inverse duration βnormalized to the Hubble
parameter H. It turns out that β/H &103, implying that the sound wave period τsw
as an active GW source, too, can be much shorter than the Hubble time. We therefore
compute τswHand use it as the reduction factor for the sound wave contribution. The
signal-to-noise ratio (SNR) for Deci-Hertz Interferometer Gravitational Wave Observatory
(DECIGO) and Big Bang Observer (BBO) is evaluated, with the result: SNRDECIGO .1.2
and SNRBBO .12.0 for five years observation, from which we conclude that the GW signal
predicted by the model in the optimistic case could be detected at BBO.
Keywords: particle physics - cosmology connection, gravitational waves / theory
ArXiv ePrint: 1910.05025
c
2020 IOP Publishing Ltd and Sissa Medialab https://doi.org/10.1088/1475-7516/2020/04/001
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