التفاصيل البيبلوغرافية
| العنوان: |
Novel CMB constraints on the α parameter in alpha-attractor models |
| المؤلفون: |
Iacconi, Laura, Fasiello, Matteo, Valiviita, Jussi, Wands, David |
| المساهمون: |
Department of Physics, Helsinki Institute of Physics, Particle Physics and Astrophysics |
| بيانات النشر: |
IOP Publishing |
| سنة النشر: |
2024 |
| المجموعة: |
Helsingfors Universitet: HELDA – Helsingin yliopiston digitaalinen arkisto |
| مصطلحات موضوعية: |
Inflation and CMBR theory, Cosmological perturbation theory, Inflation, Physics of the early universe, Astronomy, Space science, Physical sciences |
| الوصف: |
Cosmological alpha-attractors are a compelling class of inflationary models. They lead to universal predictions for large-scale observables, broadly independent from the functional form of the inflaton potential. In this work we derive improved analytical predictions for the large-scale observables, whose dependence on the duration of reheating and the parameter alpha is made explicit. We compare these with Planck and BICEP/Keck 2018 data in the framework of a Bayesian study, employing uniform logarithmic and linear priors for alpha. Our improved universal predictions allow direct constraints on the duration of reheating. Furthermore, while it is well-known that CMB constraints on the tensor-to-scalar ratio can be used to place an upper bound on the alpha parameter, we demonstrate that including the alpha-dependence of the scalar spectral tilt yields novel constraints on alpha. In particular, for small alpha, the scalar spectral tilt scales with log(10) alpha, regardless of the specific potential shape. For decreasing alpha, this eventually puts the models in tension with CMB measurements, bounding the magnitude of a from below. Therefore, in addition to the upper bound from the tensor-to-scalar ratio, we derive the first lower bound on the magnitude of alpha for alpha-attractor T-models, log(10) alpha = -4.2(-8.6)(+5.4) at 95% C.L. ; Peer reviewed |
| نوع الوثيقة: |
article in journal/newspaper |
| وصف الملف: |
application/pdf |
| اللغة: |
English |
| Relation: |
The authors are especially grateful to Seshadri Nadathur for help with the MCMC sampler. LI would like to thank Guilherme Brando, Juan Carlos Hidalgo, Natalie B. Hogg and Francisco X. Linares Cedeno for interesting discussions. LI is supported by a Royal Society funded postdoctoral position. MF acknowledges support from the "Ramon y Cajal" grant RYC2021-033786-I. MF's work is partially supported by the Spanish Research Agency (Agencia Estatal de Investigacion) through the Grant IFT Centro de Excelencia Severo Ochoa No CEX2020-001007-S, funded by MCIN/AEI/10.13039/501100011033. JV acknowledges support from Ruth och Nils-Erik Stenbacks Stiftelse and the Academy of Finland grant 347088. DW is supported by the Science and Technology Facilities Council, grant number ST/W001225/1. Supporting research data are available on reasonable request from the corresponding author, Laura Iacconi.; Iacconi , L , Fasiello , M , Valiviita , J & Wands , D 2023 , ' Novel CMB constraints on the α parameter in alpha-attractor models ' , Journal of Cosmology and Astroparticle Physics , vol. 2023 , no. 10 , 015 . https://doi.org/10.1088/1475-7516/2023/10/015; ORCID: /0000-0001-6225-3693/work/152929810; http://hdl.handle.net/10138/570820; 4ce617f6-5c81-40dd-8d64-f8dcf6ed12bc; 85175020245; 001142721200004 |
| الاتاحة: |
http://hdl.handle.net/10138/570820 |
| Rights: |
cc_by ; info:eu-repo/semantics/openAccess ; openAccess |
| رقم الانضمام: |
edsbas.B420D334 |
| قاعدة البيانات: |
BASE |