Cosmic Strings from Tribrid Inflation

Author(s)

Antusch, Stefan, Trailović, Katarina

Abstract

Tribrid inflation is a class of supersymmetric inflation models where the scalar component of a matter superfield, or a $D$-flat direction of matter fields, drives inflation. Similar to Hybrid inflation, the end of inflation is reached when a "waterfall field", which was stabilized during inflation at a field value where the scalar potential features a large vacuum energy, starts rapidly rolling towards its minimum where a symmetry group $G$ is spontaneously broken. In contrast to standard supersymmetric Hybrid inflation, where the inflaton is a gauge singlet, in Tribrid inflation it can be a gauge non-singlet, which, via its vacuum expectation value, already breaks the gauge symmetry. This raises the question whether topological defects can still form after inflation in this class of models, and if so, which types of defects are generated. We investigate this question systematically in realisations of Tribrid inflation where $G = U(1)$ and we analyse under which conditions cosmic strings form. We find that in the considered cases where domain walls form, these are only temporary and do not invalidate the model realisations. We also discuss how our results can be used to analyse models of Tribrid inflation associated with the final step of $SO(10)$ breaking, where cosmic strings can be metastable and provide a promising explanation of the recent PTA results hinting at a stochastic gravitational wave background at nanohertz frequencies.

Figures

Illustration of the evolution of the potential of $H$ as the inflaton rolls towards zero. On the left: the potential of $H$ when $|\phi_{\text{crit}2}|<|\langle \phi\rangle|<|\phi_{\text{crit}1}|$, where domain walls have formed. In the middle: the potential of $H$ when $|\langle \phi\rangle|<|\phi_{\text{crit}2}|$, where cosmic strings have formed on top of the domain walls, which now have lower energy density. On the right: the potential of $H$ when $|\langle \phi\rangle|=|\langle \bar{\phi}\rangle|=0$, where the domain walls have vanished while the cosmic strings still persist.

Illustration of the evolution of the potential of $H$ as the inflaton rolls towards zero. On the left: the potential of $H$ when $|\phi_{\text{crit}2}|<|\langle \phi\rangle|<|\phi_{\text{crit}1}|$, where domain walls have formed. In the middle: the potential of $H$ when $|\langle \phi\rangle|<|\phi_{\text{crit}2}|$, where cosmic strings have formed on top of the domain walls, which now have lower energy density. On the right: the potential of $H$ when $|\langle \phi\rangle|=|\langle \bar{\phi}\rangle|=0$, where the domain walls have vanished while the cosmic strings still persist.


References
  • [1] A. H. Guth, Phys. Rev. D 23 (1981), 347-356 doi:10.1103/PhysRevD.23.347
  • [2] A. Albrecht and P. J. Steinhardt, Phys. Rev. Lett. 48 (1982), 1220-1223 doi:10.1103/PhysRevLett.48.1220
  • [3] A. D. Linde, Phys. Lett. B 108 (1982), 389-393 doi:10.1016/0370-2693(82)91219-9
  • [4] A. D. Linde, Phys. Lett. B 129 (1983), 177-181 doi:10.1016/0370-2693(83)90837-7
  • [5] T. W. B. Kibble, J. Phys. A 9 (1976), 1387-1398 doi:10.1088/0305-4470/9/8/029
  • [6] J. Preskill, Phys. Rev. Lett. 43 (1979), 1365 doi:10.1103/PhysRevLett.43.1365
  • [7] M. B. Hindmarsh and T. W. B. Kibble, Rept. Prog. Phys. 58 (1995), 477-562 doi:10.1088/0034-4885/58/5/001 [arXiv:hep-ph/9411342 [hep-ph]].
  • [8] A. D. Linde, Phys. Rev. D 49 (1994), 748-754 doi:10.1103/PhysRevD.49.748 [arXiv:astro-ph/9307002 [astro-ph]].
  • [9] E. J. Copeland, A. R. Liddle, D. H. Lyth, E. D. Stewart and D. Wands, Phys. Rev. D 49 (1994), 6410-6433 doi:10.1103/PhysRevD.49.6410 [arXiv:astro-ph/9401011 [astro-ph]].
  • [10] G. R. Dvali, Q. Shafi and R. K. Schaefer, Phys. Rev. Lett. 73 (1994), 1886-1889 doi:10.1103/PhysRevLett.73.1886 [arXiv:hep-ph/9406319 [hep-ph]].
  • [11] A. D. Linde and A. Riotto, Phys. Rev. D 56 (1997), R1841-R1844 doi:10.1103/PhysRevD.56.R1841 [arXiv:hep-ph/9703209 [hep-ph]].
  • [12] S. Antusch, K. Dutta and P. M. Kostka, AIP Conf. Proc. 1200 (2010) no.1, 1007-1010 doi:10.1063/1.3327524 [arXiv:0908.1694 [hep-ph]].
  • [13] S. Antusch, M. Bastero-Gil, K. Dutta, S. F. King and P. M. Kostka, JCAP 01 (2009), 040 doi:10.1088/1475-7516/2009/01/040 [arXiv:0808.2425 [hep-ph]].
  • [14] S. Antusch, K. Dutta and P. M. Kostka, Phys. Lett. B 677 (2009), 221-225 doi:10.1016/j.physletb.2009.05.043 [arXiv:0902.2934 [hep-ph]].
  • [15] S. Antusch, M. Bastero-Gil, S. F. King and Q. Shafi, Phys. Rev. D 71 (2005), 083519 doi:10.1103/PhysRevD.71.083519 [arXiv:hep-ph/0411298 [hep-ph]].
  • [16] S. Antusch, M. Bastero-Gil, J. P. Baumann, K. Dutta, S. F. King and P. M. Kostka, JHEP 08 (2010), 100 doi:10.1007/JHEP08(2010)100 [arXiv:1003.3233 [hep-ph]].
  • [17] M. A. Masoud, M. U. Rehman and Q. Shafi, JCAP 11 (2021), 022 doi:10.1088/1475-7516/2021/11/022 [arXiv:2107.09689 [hep-ph]].
  • [18] S. Antusch, K. Hinze, S. Saad and J. Steiner, Phys. Rev. D 108 (2023) no.9, 095053 doi:10.1103/PhysRevD.108.095053 [arXiv:2307.04595 [hep-ph]].
  • [19] G. Agazie et al. [NANOGrav], Astrophys. J. Lett. 951 (2023) no.1, L8 doi:10.3847/2041-8213/acdac6 [arXiv:2306.16213 [astro-ph.HE]].
  • [20] J. Antoniadis et al. [EPTA and InPTA:], Astron. Astrophys. 678 (2023), A50 doi:10.1051/0004-6361/202346844 [arXiv:2306.16214 [astro-ph.HE]].
  • [21] H. Xu, S. Chen, Y. Guo, J. Jiang, B. Wang, J. Xu, Z. Xue, R. N. Caballero, J. Yuan and Y. Xu, et al. Res. Astron. Astrophys. 23 (2023) no.7, 075024 doi:10.1088/1674-4527/acdfa5 [arXiv:2306.16216 [astro-ph.HE]].
  • [22] D. J. Reardon, A. Zic, R. M. Shannon, G. B. Hobbs, M. Bailes, V. Di Marco, A. Kapur, A. F. Rogers, E. Thrane and J. Askew, et al. Astrophys. J. Lett. 951 (2023) no.1, L6 doi:10.3847/2041-8213/acdd02 [arXiv:2306.16215 [astro-ph.HE]].
  • [23] M. Bastero-Gil, S. F. King and Q. Shafi, Phys. Lett. B 651 (2007), 345-351 doi:10.1016/j.physletb.2006.06.085 [arXiv:hep-ph/0604198 [hep-ph]].
  • [24] M. U. Rehman, Q. Shafi and J. R. Wickman, Phys. Lett. B 683 (2010), 191-195 doi:10.1016/j.physletb.2009.12.010 [arXiv:0908.3896 [hep-ph]].
  • [25] K. Nakayama, F. Takahashi and T. T. Yanagida, JCAP 12 (2010), 010 doi:10.1088/1475-7516/2010/12/010 [arXiv:1007.5152 [hep-ph]].
  • [26] S. Antusch and D. Nolde, JCAP 11 (2012), 005 doi:10.1088/1475-7516/2012/11/005 [arXiv:1207.6111 [hep-ph]].
  • [27] W. Buchmüller, V. Domcke, K. Kamada and K. Schmitz, JCAP 07 (2014), 054 doi:10.1088/1475-7516/2014/07/054 [arXiv:1404.1832 [hep-ph]].
  • [28] K. Schmitz and T. T. Yanagida, Phys. Rev. D 98 (2018) no.7, 075003 doi:10.1103/PhysRevD.98.075003 [arXiv:1806.06056 [hep-ph]].
  • [29] A. Afzal et al. [NANOGrav], Astrophys. J. Lett. 951 (2023) no.1, L11 doi:10.3847/2041-8213/acdc91 [arXiv:2306.16219 [astro-ph.HE]].
  • [30] J. Antoniadis et al. [EPTA and InPTA], Astron. Astrophys. 685 (2024), A94 doi:10.1051/0004-6361/202347433 [arXiv:2306.16227 [astro-ph.CO]].