Axion effective potentials induced by heavy sterile fermions
Abstract A model of (3 + 1)-dimensional leptogenesis, proposed previously by the authors, requires a CPT Violating (CPTV) background of the Kalb–Ramond (KR) axion field. The KR axion is a pseudoscalar, which is dual to the field strength of the spin-one field present in the massless gravitational mu...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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SpringerOpen
2023-09-01
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| Series: | European Physical Journal C: Particles and Fields |
| Online Access: | https://doi.org/10.1140/epjc/s10052-023-12049-x |
| _version_ | 1797647168384794624 |
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| author | Nick E. Mavromatos Sarben Sarkar |
| author_facet | Nick E. Mavromatos Sarben Sarkar |
| author_sort | Nick E. Mavromatos |
| collection | DOAJ |
| description | Abstract A model of (3 + 1)-dimensional leptogenesis, proposed previously by the authors, requires a CPT Violating (CPTV) background of the Kalb–Ramond (KR) axion field. The KR axion is a pseudoscalar, which is dual to the field strength of the spin-one field present in the massless gravitational multiplet in the theory of closed bosonic strings (compactified to four dimensions). Microscopic models for the emergence of such backgrounds are provided both by low-energy string-inspired gravitational theories with torsion (including (primordial) gravitational and axial gauge anomalies) and by Einstein–Cartan gravity, a closely related simpler model. In this work we examine the pseudoscalar quanta of the KR axion in this background using the methods of effective field theory. In our model for leptogenesis there is a single sterile right-handed neutrino (RHN) with mass $$m_N.$$ m N . At energies lower than $$m_N,$$ m N , an axion potential is derived by integrating out at one loop the sterile neutrino in the spirit of effective field theory. The stability of this axion potential is important for the viability of our model. The vacuum of this potential is generally metastable. The stability of the vacuum is determined by the ratio of the torsion-induced-axion coupling (which depends on the string mass scale) to $$m_N,$$ m N , which should be larger or equal to one, for the validity of our effective field theory. The vacuum is metastable only for axion couplings much larger than the sterile neutrino mass (large string mass scales, e.g. comparable to the four-dimensional Planck mass), with a lifetime much larger than the age of the observable Universe. By contrast, if axion couplings are comparable to the RHN mass the false vacuum is highly unstable, with a lifetime much smaller than the age of the observable Universe; in this case the CPTV leptogenesis scenario is not viable. |
| first_indexed | 2024-03-11T15:12:28Z |
| format | Article |
| id | doaj.art-1d8fd2630a314b3c8c0cee3f782bc83c |
| institution | Directory Open Access Journal |
| issn | 1434-6052 |
| language | English |
| last_indexed | 2024-03-11T15:12:28Z |
| publishDate | 2023-09-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | European Physical Journal C: Particles and Fields |
| spelling | doaj.art-1d8fd2630a314b3c8c0cee3f782bc83c2023-10-29T12:34:31ZengSpringerOpenEuropean Physical Journal C: Particles and Fields1434-60522023-09-0183912110.1140/epjc/s10052-023-12049-xAxion effective potentials induced by heavy sterile fermionsNick E. Mavromatos0Sarben Sarkar1Physics Department, School of Applied Mathematical and Physical Sciences, National Technical University of AthensTheoretical Particle Physics and Cosmology Group, Department of Physics, King’s College LondonAbstract A model of (3 + 1)-dimensional leptogenesis, proposed previously by the authors, requires a CPT Violating (CPTV) background of the Kalb–Ramond (KR) axion field. The KR axion is a pseudoscalar, which is dual to the field strength of the spin-one field present in the massless gravitational multiplet in the theory of closed bosonic strings (compactified to four dimensions). Microscopic models for the emergence of such backgrounds are provided both by low-energy string-inspired gravitational theories with torsion (including (primordial) gravitational and axial gauge anomalies) and by Einstein–Cartan gravity, a closely related simpler model. In this work we examine the pseudoscalar quanta of the KR axion in this background using the methods of effective field theory. In our model for leptogenesis there is a single sterile right-handed neutrino (RHN) with mass $$m_N.$$ m N . At energies lower than $$m_N,$$ m N , an axion potential is derived by integrating out at one loop the sterile neutrino in the spirit of effective field theory. The stability of this axion potential is important for the viability of our model. The vacuum of this potential is generally metastable. The stability of the vacuum is determined by the ratio of the torsion-induced-axion coupling (which depends on the string mass scale) to $$m_N,$$ m N , which should be larger or equal to one, for the validity of our effective field theory. The vacuum is metastable only for axion couplings much larger than the sterile neutrino mass (large string mass scales, e.g. comparable to the four-dimensional Planck mass), with a lifetime much larger than the age of the observable Universe. By contrast, if axion couplings are comparable to the RHN mass the false vacuum is highly unstable, with a lifetime much smaller than the age of the observable Universe; in this case the CPTV leptogenesis scenario is not viable.https://doi.org/10.1140/epjc/s10052-023-12049-x |
| spellingShingle | Nick E. Mavromatos Sarben Sarkar Axion effective potentials induced by heavy sterile fermions European Physical Journal C: Particles and Fields |
| title | Axion effective potentials induced by heavy sterile fermions |
| title_full | Axion effective potentials induced by heavy sterile fermions |
| title_fullStr | Axion effective potentials induced by heavy sterile fermions |
| title_full_unstemmed | Axion effective potentials induced by heavy sterile fermions |
| title_short | Axion effective potentials induced by heavy sterile fermions |
| title_sort | axion effective potentials induced by heavy sterile fermions |
| url | https://doi.org/10.1140/epjc/s10052-023-12049-x |
| work_keys_str_mv | AT nickemavromatos axioneffectivepotentialsinducedbyheavysterilefermions AT sarbensarkar axioneffectivepotentialsinducedbyheavysterilefermions |