The scalar chemical potential in cosmological collider physics
Abstract Non-analyticity in co-moving momenta within the non-Gaussian bispectrum is a distinctive sign of on-shell particle production during inflation, presenting a unique opportunity for the “direct detection” of particles with masses as large as the inflationary Hubble scale (H). However, the str...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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SpringerOpen
2021-02-01
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| Series: | Journal of High Energy Physics |
| Subjects: | |
| Online Access: | https://doi.org/10.1007/JHEP02(2021)079 |
| _version_ | 1831737130249879552 |
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| author | Arushi Bodas Soubhik Kumar Raman Sundrum |
| author_facet | Arushi Bodas Soubhik Kumar Raman Sundrum |
| author_sort | Arushi Bodas |
| collection | DOAJ |
| description | Abstract Non-analyticity in co-moving momenta within the non-Gaussian bispectrum is a distinctive sign of on-shell particle production during inflation, presenting a unique opportunity for the “direct detection” of particles with masses as large as the inflationary Hubble scale (H). However, the strength of such non-analyticity ordinarily drops exponentially by a Boltzmann-like factor as masses exceed H. In this paper, we study an exception provided by a dimension-5 derivative coupling of the inflaton to heavy-particle currents, applying it specifically to the case of two real scalars. The operator has a “chemical potential” form, which harnesses the large kinetic energy scale of the inflaton, ϕ ⋅ 0 1 / 2 ≈ 60 H $$ {\overset{\cdot }{\phi}}_0^{1/2}\approx 60H $$ , to act as an efficient source of scalar particle production. Derivative couplings of inflaton ensure radiative stability of the slow-roll potential, which in turn maintains (approximate) scale-invariance of the inflationary correlations. We show that a signal not suffering Boltzmann suppression can be obtained in the bispectrum with strength f NL ∼ O $$ \mathcal{O} $$ (0.01–10) for an extended range of scalar masses ≲ ϕ ⋅ 0 1 / 2 $$ \lesssim {\overset{\cdot }{\phi}}_0^{1/2} $$ , potentially as high as 1015 GeV, within the sensitivity of upcoming LSS and more futuristic 21-cm experiments. The mechanism does not invoke any particular fine-tuning of parameters or breakdown of perturbation-theoretic control. The leading contribution appears at tree-level, which makes the calculation analytically tractable and removes the loop-suppression as compared to earlier chemical potential studies of non-zero spins. The steady particle production allows us to infer the effective mass of the heavy particles and the chemical potential from the variation in bispectrum oscillations as a function of co-moving momenta. Our analysis sets the stage for generalization to heavy bosons with non-zero spin. |
| first_indexed | 2024-12-21T12:58:14Z |
| format | Article |
| id | doaj.art-e15cb72c77074c4f92b56d051defd4ef |
| institution | Directory Open Access Journal |
| issn | 1029-8479 |
| language | English |
| last_indexed | 2024-12-21T12:58:14Z |
| publishDate | 2021-02-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Journal of High Energy Physics |
| spelling | doaj.art-e15cb72c77074c4f92b56d051defd4ef2022-12-21T19:03:17ZengSpringerOpenJournal of High Energy Physics1029-84792021-02-012021213810.1007/JHEP02(2021)079The scalar chemical potential in cosmological collider physicsArushi Bodas0Soubhik Kumar1Raman Sundrum2Maryland Center for Fundamental Physics, Department of Physics, University of MarylandMaryland Center for Fundamental Physics, Department of Physics, University of MarylandMaryland Center for Fundamental Physics, Department of Physics, University of MarylandAbstract Non-analyticity in co-moving momenta within the non-Gaussian bispectrum is a distinctive sign of on-shell particle production during inflation, presenting a unique opportunity for the “direct detection” of particles with masses as large as the inflationary Hubble scale (H). However, the strength of such non-analyticity ordinarily drops exponentially by a Boltzmann-like factor as masses exceed H. In this paper, we study an exception provided by a dimension-5 derivative coupling of the inflaton to heavy-particle currents, applying it specifically to the case of two real scalars. The operator has a “chemical potential” form, which harnesses the large kinetic energy scale of the inflaton, ϕ ⋅ 0 1 / 2 ≈ 60 H $$ {\overset{\cdot }{\phi}}_0^{1/2}\approx 60H $$ , to act as an efficient source of scalar particle production. Derivative couplings of inflaton ensure radiative stability of the slow-roll potential, which in turn maintains (approximate) scale-invariance of the inflationary correlations. We show that a signal not suffering Boltzmann suppression can be obtained in the bispectrum with strength f NL ∼ O $$ \mathcal{O} $$ (0.01–10) for an extended range of scalar masses ≲ ϕ ⋅ 0 1 / 2 $$ \lesssim {\overset{\cdot }{\phi}}_0^{1/2} $$ , potentially as high as 1015 GeV, within the sensitivity of upcoming LSS and more futuristic 21-cm experiments. The mechanism does not invoke any particular fine-tuning of parameters or breakdown of perturbation-theoretic control. The leading contribution appears at tree-level, which makes the calculation analytically tractable and removes the loop-suppression as compared to earlier chemical potential studies of non-zero spins. The steady particle production allows us to infer the effective mass of the heavy particles and the chemical potential from the variation in bispectrum oscillations as a function of co-moving momenta. Our analysis sets the stage for generalization to heavy bosons with non-zero spin.https://doi.org/10.1007/JHEP02(2021)079Cosmology of Theories beyond the SMEffective Field Theories |
| spellingShingle | Arushi Bodas Soubhik Kumar Raman Sundrum The scalar chemical potential in cosmological collider physics Journal of High Energy Physics Cosmology of Theories beyond the SM Effective Field Theories |
| title | The scalar chemical potential in cosmological collider physics |
| title_full | The scalar chemical potential in cosmological collider physics |
| title_fullStr | The scalar chemical potential in cosmological collider physics |
| title_full_unstemmed | The scalar chemical potential in cosmological collider physics |
| title_short | The scalar chemical potential in cosmological collider physics |
| title_sort | scalar chemical potential in cosmological collider physics |
| topic | Cosmology of Theories beyond the SM Effective Field Theories |
| url | https://doi.org/10.1007/JHEP02(2021)079 |
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