Academia.eduAcademia.edu

Outline

Title
Abstract
Introduction
Pre-Inflationary Dynamics: Classical Analysis
Analytic Approximations in Simple Cases
Conclusions
References

Classical and quantum initial conditions for Higgs inflation

Profile image of Alberto SalvioAlberto Salvio

2015, Physics Letters B

https://doi.org/10.1016/J.PHYSLETB.2015.09.020
visibility

…

description

8 pages

link

1 file

Abstract

We investigate whether Higgs inflation can occur in the Standard Model starting from natural initial conditions or not. The Higgs has a non-minimal coupling to the Ricci scalar. We confine our attention to the regime where quantum Einstein gravity effects are small in order to have results that are independent of the ultraviolet completion of gravity. At the classical level we find no tuning is required to have a successful Higgs inflation, provided the initial homogeneity condition is satisfied. On the other hand, at the quantum level we obtain that the renormalization for large non-minimal coupling requires an additional degree of freedom that transforms Higgs inflation into Starobinsky R 2 inflation, unless a tuning of the initial values of the running parameters is made.

Related papers

Higgs inflation: consistency and generalisations
Amaury Magnin

Journal of High Energy Physics, 2011

We analyse the self-consistency of inflation in the Standard Model, where the Higgs field has a large non-minimal coupling to gravity. We determine the domain of energies in which this model represents a valid effective field theory as a function of the background Higgs field. This domain is bounded above by the cutoff scale which is found to be higher than the relevant dynamical scales throughout the whole history of the Universe, including the inflationary epoch and reheating. We present a systematic scheme to take into account quantum loop corrections to the inflationary calculations within the framework of effective field theory. We discuss the additional assumptions that must be satisfied by the ultraviolet completion of the theory to allow connection between the parameters of the inflationary effective theory and those describing the low-energy physics relevant for the collider experiments. A class of generalisations of inflationary theories with similar properties is constructed.

View PDFchevron_right
Ruling out critical Higgs inflation?
Isabella Masina

Physical Review D

We consider critical Higgs inflation, namely Higgs inflation with a rising inflection point at smaller field values than those of the plateau induced by the non-minimal coupling to gravity. It has been proposed that such configuration is compatible with the present CMB observational constraints on inflation, and also with primordial black hole production accounting for the totality or a fraction of the observed dark matter. We study the model taking into account the NNLO corrections to the Higgs effective potential: such corrections are extremely important to reduce the theoretical error associated to the calculation. We find that, in the 3 σ window for the relevant low energy parameters, which are the strong coupling and the Higgs mass (the top mass follows by requiring an inflection point), the potential at the inflection point is so large (and so is the Hubble constant during inflation) that the present bound on the tensor-to-scalar ratio is violated. The model is viable only allowing the strong coupling to take its upper 3 − 4 σ value. In our opinion, this tension shows that the model of critical Higgs inflation is likely to be not viable: neither inflation nor black holes as dark matter can be originated in this version of the model.

View PDFchevron_right
Higgs inflation from standard model criticality
Hikaru KAWAI

Physical Review D, 2015

The observed Higgs mass M H = 125.9 ± 0.4 GeV leads to the criticality of the Standard Model, that is, the Higgs potential becomes flat around the scale 10 17-18 GeV for the top mass 171.3 GeV. Earlier we have proposed a Higgs inflation scenario in which this criticality plays a crucial role. In this paper, we investigate the detailed cosmological predictions of this scenario in light of the latest Planck and BICEP2 results. We also consider the Higgs portal scalar dark matter model, and compute the Higgs one-loop effective potential with the two-loop renormalization group improvement. We find a constraint on the coupling between Higgs and dark matter which depends on the inflationary parameters.

View PDFchevron_right
Higgs-Dilaton Inflation and Primordial Black Holes from Critical Higgs Inflation
Juan Garcia-Bellido

2017

View PDFchevron_right
Two fields quintessential Higgs Inflation
Mehdi Eshaghi

arXiv (Cornell University), 2020

We study a two-field quintessential Higgs inflation model in which a quintessence field with an exponential potential e −βφ/M P is coupled to the Higgs field from the beginning of inflation. The Higgs field itself is also non-minimally coupled to gravity. The inflationary predictions of this model for n s and r are in good agreement with Planck 2018 data. We calculate the observables n s and r against the free parameter β. Comparing these parameters with the observed n s and r in Planck 2018 paper, we find β 8 × 10 −3 that strongly disfavors the Swampland conjecture. I. INTRODUCTION Cosmologists consider two accelerating eras of cosmic expansion history. The first is an inflationary era where a scalar field, called inflaton, with negative pressure and a slowroll evolution, is responsible for accelerating expansion in the early universe [1]. Based on the latest Planck papers [2, 3], single field potentials with plateau-like shapes are the most favored inflationary models by Planck temperature, polarization, and lensing data combined with the BICEP2/Keck Array BK15 data. In between the single field inflationary models, the Higgs model [4, 5] has the best consistency with the Planck 2018 data. It belongs to a general class of inflationary models where a scalar field has a non-minimal coupling to gravity [6].

View PDFchevron_right
Two-Field quintessential Higgs Inflation
Mehdi Eshaghi

arXiv (Cornell University), 2020

We study a two-field quintessential Higgs inflation model in which a quintessence field with an exponential potential e −βφ/M P is coupled to the Higgs field from the beginning of inflation. The Higgs field itself is also non-minimally coupled to gravity. The inflationary predictions of this model for n s and r are in good agreement with Planck 2018 data. We calculate the observables n s and r against the free parameter β. Comparing these parameters with the observed n s and r in Planck 2018 paper, we find β 8 × 10 −3 that strongly disfavors the Swampland conjecture. I. INTRODUCTION Cosmologists consider two accelerating eras of cosmic expansion history. The first is an inflationary era where a scalar field, called inflaton, with negative pressure and a slowroll evolution, is responsible for accelerating expansion in the early universe [1]. Based on the latest Planck papers [2, 3], single field potentials with plateau-like shapes are the most favored inflationary models by Planck temperature, polarization, and lensing data combined with the BICEP2/Keck Array BK15 data. In between the single field inflationary models, the Higgs model [4, 5] has the best consistency with the Planck 2018 data. It belongs to a general class of inflationary models where a scalar field has a non-minimal coupling to gravity [6].

View PDFchevron_right
Planck constraints on Higgs modulated reheating of renormalization group improved inflation
Damien Easson

Physical Review D, 2013

Within the framework of RG improved inflationary cosmology motivated by asymptotically safe gravity, we study the dynamics of a scalar field which can be interpreted as the Higgs field. The background trajectories of this model can provide sufficient inflationary e-folds and a graceful exit to a radiation dominated phase. We study the possibility of generating primordial curvature perturbations through the Standard Model Higgs boson. This can be achieved under finely tuned parameter choices by making use of the modulated reheating mechanism. The primordial non-gaussianity is expected to be sizable in this model. Though tightly constrained by the newly released Planck CMB data, this model provides a potentially interesting connection between collider and early universe physics.

View PDFchevron_right
Higgs Inflation in f (\ Phi, R) Theory
Subhendra Singh

arXiv preprint arXiv:1303.3870, 2013

We have generalized the curvature coupling models of Higgs inflation to study inflation with a scalar field coupling of the form ξΦ a R b M a+2b−4 p . Such higher order scalar and graviton terms can be expected from the renormalization close to Planck scale. We compute the amplitude and spectral index of curvature perturbations generated during inflation and fix the parameters of the model by comparing these with the Planck+WP data. We find that if the scalar self coupling λ is in the range (10 −5 − 0.1), parameter a in the range (2.3 − 3.6) and b in the range (0.68 − 0.22) at the Planck scale, one can have a viable inflation model even for ξ ≃ 1. The tensor to scalar ratio r in this model is small and our model with scalar-curvature couplings is not ruled out by observational limits on r unlike the pure λ 4 Φ 4 theory. By requiring the curvature coupling parameter to be of order unity, we have evaded the problem of unitarity violation in scalar-graviton scatterings which plague the ξΦ 2 R Higgs inflation models. We conclude that the Higgs field may still be a good candidate for being the inflaton in the early universe if one considers higher dimensional curvature coupling.

View PDFchevron_right
HIGGS INFLATION IN f(Φ, R) THEORY
Naveen Kumar Singh

International Journal of Modern Physics D, 2014

We generalize the scalar-curvature coupling model ξΦ2R of Higgs inflation to ξΦaRb to study inflation. We compute the amplitude and spectral index of curvature perturbations generated during inflation and fix the parameters of the model by comparing these with the Planck + WP data. We find that if the scalar self-coupling λ is in the range 10-5–0.1, parameter a in the range 2.3–3.6 and b in the range 0.77–0.22 at the Planck scale, one can have a viable inflation model even for ξ ≃ 1. The tensor to scalar ratio r in this model is small and our model with scalar-curvature couplings is not ruled out by observational limits on r unlike the pure [Formula: see text] theory. By requiring the curvature coupling parameter to be of order unity, we have evaded the problem of unitarity violation in scalar-graviton scatterings which plague the ξΦ2R Higgs inflation models. We conclude that the Higgs field may still be a good candidate for being the inflaton in the early universe if one considers ...

View PDFchevron_right
Cosmological implications of Standard Model criticality and Higgs inflation
Hikaru KAWAI

Nuclear Physics B, 2020

The observed Higgs mass indicates that the Standard Model can be valid up to near the Planck scale M P. Within this framework, it is important to examine how little modification is necessary to fit the recent experimental results in particle physics and cosmology. As a minimal extension, we consider the possibility that the Higgs field plays the role of inflaton and that the dark matter is the Higgs-portal scalar field. We assume that the extended Standard Model is valid up to the string scale 10 17 GeV. (This translates to the assumption that all the non-minimal couplings are not particularly large, ξ 10 2 , as in the critical Higgs inflation, since M P / √ 10 2 ∼ 10 17 GeV.) We find a correlated theoretical bound on the tensor-to-scalar ratio r and the dark matter mass m DM. As a result, the Planck bound r < 0.09 implies that the dark-matter mass must be smaller than 1.1 TeV, while the PandaX-II bound on the dark-matter mass m DM > 0.7 ± 0.2 TeV leads to r 2 × 10 −3. Both are within the range of near-future detection. When we include the right-handed neutrinos of mass M R ∼ 10 14 GeV, the allowed region becomes wider, but we still predict r 10 −3 in the most of the parameter space. The most conservative bound becomes r > 10 −5 if we allow three-parameter tuning of m DM , M R , and the top-quark mass.

View PDFchevron_right

References (49)

  1. A. H. Guth, "The Inflationary Universe: A Possible Solution to the Horizon and Flatness Problems," Phys. Rev. D 23, 347 (1981).
  2. A. D. Linde, "A New Inflationary Universe Scenario: A Possible So- lution of the Horizon, Flatness, Homogeneity, Isotropy and Primordial Monopole Problems," Phys. Lett. B 108, 389 (1982).
  3. A. Albrecht and P. J. Steinhardt, "Cosmology for Grand Unified The- ories with Radiatively Induced Symmetry Breaking," Phys. Rev. Lett. 48, 1220 (1982).
  4. P. A. R. Ade et al. [Planck Collaboration], "Planck 2015 results. XIII. Cosmological parameters," arXiv:1502.01589. P. A. R. Ade et al. [Planck Collaboration], "Planck 2015 results. XX. Constraints on inflation," arXiv:1502.02114.
  5. V. F. Mukhanov, H. A. Feldman and R. H. Brandenberger, "Theory of cosmological perturbations. Part 1. Classical perturbations. Part 2. Quantum theory of perturbations. Part 3. Extensions," Phys. Rept. 215, 203 (1992).
  6. A. Mazumdar and J. Rocher, "Particle physics models of inflation and curvaton scenarios," Phys. Rept. 497, 85 (2011) [arXiv:1001.0993].
  7. G. Aad et al. [ATLAS Collaboration], "Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC," Phys. Lett. B 716 (2012) 1 [arXiv:1207.7214].
  8. S. Chatrchyan et al. [CMS Collaboration], "Observation of a new bo- son at a mass of 125 GeV with the CMS experiment at the LHC," Phys. Lett. B 716 (2012) 30 [arXiv:1207.7235].
  9. A. Chatterjee and A. Mazumdar, "Tuned MSSM Higgses as an infla- ton," JCAP 1109, 009 (2011) [arXiv:1103.5758].
  10. A. Chatterjee and A. Mazumdar, "Bound on largest r 0.1 from sub-Planckian excur- sions of inflaton," JCAP 1501, no. 01, 031 (2015) [arXiv:1409.4442].
  11. D. La and P. J. Steinhardt, "Extended Inflationary Cosmology," Phys. Rev. Lett. 62, 376 (1989) [Phys. Rev. Lett. 62, 1066 (1989)].
  12. F. L. Bezrukov and M. Shaposhnikov, "The Standard Model Higgs bo- son as the inflaton," Phys. Lett. B 659 (2008) 703 [arXiv:0710.3755].
  13. C. P. Burgess, H. M. Lee and M. Trott, "Power-counting and the Validity of the Classical Approximation During Inflation," JHEP 0909 (2009) 103 [arXiv:0902.4465].
  14. J. L. F. Barbon and J. R. Es- pinosa, "On the Naturalness of Higgs Inflation," Phys. Rev. D 79 (2009) 081302 [arXiv:0903.0355].
  15. C. P. Burgess, H. M. Lee and M. Trott, "Comment on Higgs Inflation and Naturalness," JHEP 1007 (2010) 007 [arXiv:1002.2730].
  16. M. P. Hertzberg, "On Inflation with Non-minimal Coupling," JHEP 1011 (2010) 023 [arXiv:1002.2995].
  17. F. Bezrukov, A. Magnin, M. Shaposhnikov and S. Sibiryakov, "Higgs inflation: consistency and generalisations," JHEP 1101 (2011) 016 [arXiv:1008.5157].
  18. C. P. Burgess, S. P. Patil and M. Trott, "On the Pre- dictiveness of Single-Field Inflationary Models," JHEP 1406 (2014) 010 [arXiv:1402.1476].
  19. J. L. F. Barbon, J. A. Casas, J. Elias-Miro and J. R. Espinosa, "Higgs Inflation as a Mirage," arXiv:1501.02231.
  20. E. J. Copeland, A. R. Liddle and D. Wands, "Exponential potentials and cosmological scaling solutions," Phys. Rev. D 57, 4686 (1998) [arXiv:gr-qc/9711068].
  21. A. R. Liddle, A. Mazumdar and F. E. Schunck, "Assisted inflation," Phys. Rev. D 58 (1998) 061301 [arXiv:astro- ph/9804177].
  22. E. J. Copeland, A. Mazumdar and N. J. Nunes, "Gener- alized assisted inflation," Phys. Rev. D 60 (1999) 083506 [arXiv:astro- ph/9904309].
  23. L. Kofman, A. D. Linde and V. F. Mukhanov, "Inflationary the- ory and alternative cosmology," JHEP 0210 (2002) 057 [arXiv:hep- th/0206088].
  24. A. D. Linde, "Initial Conditions For Inflation," Phys. Lett. B 162 (1985) 281.
  25. D. S. Goldwirth, "Initial Conditions for New Inflation," Phys. Lett. B 243 (1990) 41. D. S. Goldwirth and T. Piran, "Inhomogeneity and the Onset of Inflation," Phys. Rev. Lett. 64, 2852 (1990). A. Albrecht, R. H. Brandenberger and R. Matzner, "Inflation With Generalized Initial Conditions," Phys. Rev. D 35, 429 (1987). H. Kurki-Suonio, R. A. Matzner, J. Centrella and J. R. Wilson, "Inflation From Inho- mogeneous Initial Data in a One-dimensional Back Reacting Cosmol- ogy," Phys. Rev. D 35, 435 (1987).
  26. A. A. Starobinsky, "A New Type of Isotropic Cosmological Models Without Singularity," Phys. Lett. B 91, 99 (1980).
  27. T. Biswas, E. Gerwick, T. Koivisto and A. Mazumdar, "Towards sin- gularity and ghost free theories of gravity," Phys. Rev. Lett. 108 (2012) 031101 [arXiv:1110.5249].
  28. S. Talaganis, T. Biswas and A. Mazumdar, "Towards understanding the ultraviolet behavior of quantum loops in infinite-derivative theories of gravity," arXiv:1412.3467.
  29. Y. Hamada, H. Kawai, K. y. Oda and S. C. Park, "Higgs Inflation is Still Alive after the Results from BICEP2," Phys. Rev. Lett. 112 (2014) 24, 241301 [arXiv:1403.5043]. F. Bezrukov and M. Shaposh- nikov, "Higgs inflation at the critical point," Phys. Lett. B 734 (2014) 249 [arXiv:1403.6078].
  30. F. Bezrukov, D. Gorbunov and M. Shaposhnikov, "On ini- tial conditions for the Hot Big Bang," JCAP 0906 (2009) 029 [arXiv:0812.3622]. J. Garcia-Bellido, D. G. Figueroa and J. Rubio, "Preheating in the Standard Model with the Higgs-Inflaton coupled to gravity," Phys. Rev. D 79 (2009) 063531 [arXiv:0812.4624].
  31. G. Degrassi, S. Di Vita, J. Elias-Miro, J. R. Espinosa, G. F. Giu- dice, G. Isidori and A. Strumia, "Higgs mass and vacuum sta- bility in the Standard Model at NNLO," JHEP 1208 (2012) 098 [arXiv:1205.6497].
  32. D. Buttazzo, G. Degrassi, P. P. Giardino, G. F. Giudice, F. Sala, A. Salvio and A. Strumia, "Investigating the near-criticality of the Higgs boson," JHEP 1312 (2013) 089 [arXiv:1307.3536].
  33. G. F. Giudice, G. Isidori, A. Salvio and A. Strumia, "Softened Gravity and the Extension of the Standard Model up to Infinite Energy," JHEP 1502 (2015) 137 [arXiv:1412.2769].
  34. F. Bezrukov, M. Y. Kalmykov, B. A. Kniehl and M. Shaposhnikov, "Higgs Boson Mass and New Physics," JHEP 1210 (2012) 140 [arXiv:1205.2893].
  35. I.L. Buchbinder, D.D. Odintsov, I.L. Shapiro, "Effective Action in Quantum Gravity" (IOP, 1992). E. V. Gorbar, I. L. Shapiro, "Renor- malization group and decoupling in curved space. 2. The Standard model and beyond," JHEP 0306 (2003) 004 [arXiv:hep-ph/0303124].
  36. Y.Yoon, Y.Yoon, "Asymptotic conformal invariance of SU(2) and stan- dard models in curved space-time," Int. J. Mod. Phys. A12 (1997) 2903.
  37. A. Salvio and A. Strumia, "Agravity," JHEP 1406 (2014) 080 [arXiv:1403.4226].
  38. G. 't Hooft and M. J. G. Veltman, "One loop divergencies in the theory of gravitation," Annales Poincare Phys. Theor. A 20 (1974) 69.
  39. F. L. Bezrukov, A. Magnin and M. Shaposhnikov, "Standard Model Higgs boson mass from inflation," Phys. Lett. B 675 (2009) 88 [arXiv:0812.4950].
  40. F. Bezrukov and M. Shaposhnikov, "Standard Model Higgs boson mass from inflation: Two loop analysis," JHEP 0907 (2009) 089 [arXiv:0904.1537].
  41. A. Salvio, "Higgs Inflation at NNLO after the Boson Discovery," Phys. Lett. B 727 (2013) 234 [arXiv:1308.2244].
  42. P. A. R. Ade et al. [BICEP2 and Planck Collaborations], "Joint Anal- ysis of BICEP2 / Keck Array and Planck Data," Phys. Rev. Lett. 114 (2015) 10, 101301 [arXiv:1502.00612].
  43. P. A. R. Ade et al. [BICEP2 and Keck Array Collaborations], "BICEP2 / Keck Array V: Measure- ments of B-mode Polarization at Degree Angular Scales and 150 GHz by the Keck Array," arXiv:1502.00643. P. A. R. Ade et al. [Planck Collaboration], "Planck 2015 results. XX. Constraints on inflation," arXiv:1502.02114.
  44. K. Kannike, G. Htsi, L. Pizza, A. Racioppi, M. Raidal, A. Salvio and A. Strumia, "Dynamically Induced Planck Scale and Inflation," JHEP 1505 (2015) 065 [arXiv:1502.01334].
  45. A. Salvio, "On the Origin of Scales and Inflation," IFT-UAM/CSIC-15-033.
  46. A. Salvio, "A Simple Motivated Completion of the Standard Model below the Planck Scale: Axions and Right-Handed Neutrinos," Phys. Lett. B 743 (2015) 428 [arXiv:1501.03781]. J. Elias-Miro, J. R. Es- pinosa, G. F. Giudice, H. M. Lee and A. Strumia, "Stabilization of the Electroweak Vacuum by a Scalar Threshold Effect," JHEP 1206 (2012) 031 [arXiv:1203.0237].
  47. F. Loebbert and J. Plefka, "Quantum Gravitational Contributions to the Standard Model Effective Potential and Vacuum Stability," arXiv:1502.03093.
  48. M. Torabian, "When Higgs Meets Starobinsky in the Early Universe," arXiv:1410.1744.
  49. F. L. Bezrukov and D. S. Gorbunov, "Distinguishing between R 2 -inflation and Higgs-inflation," Phys. Lett. B 713 (2012) 365 [arXiv:1111.4397].

Related papers

Minimal Higgs inflation
Hikaru KAWAI

Progress of Theoretical and Experimental Physics, 2014

We consider a possibility that the Higgs field in the Standard Model (SM) serves as an inflaton when its value is around the Planck scale. We assume that the SM is valid up to an ultraviolet cutoff scale , which is slightly below the Planck scale, and that the Higgs potential becomes almost flat above. Contrary to the ordinary Higgs inflation scenario, we do not assume the huge non-minimal coupling, of O(10 4), of the Higgs field to the Ricci scalar. We find that must be less than 5 × 10 17 GeV in order to explain the observed fluctuation of the cosmic microwave background, no matter how we extrapolate the Higgs potential above. The scale 10 17 GeV coincides with the perturbative string scale, which suggests that the SM is directly connected with string theory. For this to be true, the top quark mass is restricted to around 171 GeV, with which can exceed 10 17 GeV. As a concrete example of the potential above , we propose a simple log-type potential. The predictions of this specific model for the e-foldings N * = 50-60 are consistent with the current observation, namely, the scalar spectral index is n s = 0.977-0.983 and the tensor to scalar ratio 0 < r < 0.012-0.010. Other parameters, dn s /d ln k, n t , and their derivatives, are also consistent.

View PDFchevron_right
Asymptotic freedom in inflationary cosmology with a non-minimally coupled Higgs field
A. Starobinsky

Journal of Cosmology and Astroparticle Physics, 2009

We consider the renormalization group improvement in the theory of the Standard Model Higgs boson playing the role of an inflaton with a strong non-minimal coupling to gravity. It suggests the range of the Higgs mass 135.6 GeV M H 184.5 GeV compatible with the current CMB data (the lower WMAP bound on n s ), which is close to the widely accepted range dictated by the electroweak vacuum stability and perturbation theory bounds. We find the phenomenon of asymptotic freedom induced by this non-minimal curvature coupling, which brings the theory to the weak coupling domain everywhere except at the lower and upper boundary of this range. The renormalization group running of the basic quantity A I -the anomalous scaling in the non-minimally coupled Standard Model, which analytically determines all characteristics of the CMB spectrum -brings A I to small negative values at the inflation scale. This property is crucial for the above results and may also underlie the formation of initial conditions for the inflationary dynamics in quantum cosmology.

View PDFchevron_right
On the Naturalness of Higgs inflation
jose espinosa

Physical Review D, 2009

We critically examine the recent claim that the Standard Model Higgs boson H could drive inflation in agreement with observations if |H| 2 has a strong coupling ξ ∼ 10 4 to the Ricci curvature scalar. We first show that the effective theory approach upon which that claim is based ceases to be valid beyond a cutoff scale Λ = m p /ξ, where m p is the reduced Planck mass. We then argue that knowing the Higgs potential profile for the field values relevant for inflation (|H| > m p / √ ξ ≫ Λ) requires knowledge of the ultraviolet completion of the SM beyond Λ. In absence of such microscopic theory, the extrapolation of the pure SM potential beyond Λ is unwarranted and the scenario is akin to other ad-hoc inflaton potentials afflicted with significant fine-tuning. The appealing naturalness of this minimal proposal is therefore lost.

View PDFchevron_right
Inflation scenario via the Standard Model Higgs boson and LHC
A. Starobinsky

Journal of Cosmology and Astroparticle Physics, 2008

We consider a quantum corrected inflation scenario driven by a generic GUT or Standard Model type particle model whose scalar field playing the role of an inflaton has a strong non-minimal coupling to gravity. We show that currently widely accepted bounds on the Higgs mass falsify the suggestion of the paper arXiv:0710.3755 (where the role of radiative corrections was underestimated) that the Standard Model Higgs boson can serve as the inflaton. However, if the Higgs mass could be raised to ∼ 230 GeV, then the Standard Model could generate an inflationary scenario with the spectral index of the primordial perturbation spectrum ns ≃ 0.935 (barely matching present observational data) and the very low tensor-to-scalar perturbation ratio r ≃ 0.0006. * To the memory of John Archibald Wheeler.

View PDFchevron_right
Higgs inflation and the cosmological constant
Fred Jegerlehner

We discuss the impact of the Higgs discovery and its revealing a very peculiar value for the Higgs mass. It turns out that the Higgs not only induces the masses of all SM particles, the Higgs, given its special mass value, is the natural candidate for the inflaton and in fact is ruling the evolution of the early universe, by providing the necessary dark energy which remains the dominant energy density. In a previous paper I have shown that running couplings not only allow us to extrapolate SM physics up to the Planck scale, but equally important they are triggering the Higgs mechanism when the universe cools down to lower temperatures. This is possible by the fact that the bare mass term in the Higgs potential changes sign at about µ 0 ≃ 1.4 × 10 16 GeV and in the symmetric phase is enhanced by quadratic terms in the Planck mass. The huge Higgs mass term together with a Higgs induced vacuum energy play a key role in triggering inflation. We show how different terms contributing to the Higgs Lagrangian are affecting inflation. Miraculously, the huge difference between bare and renormalized cosmological constant is nullified either by the running of the SM couplings or by vacuum rearrangement somewhat before the Higgs phase transition takes place. This solves the notorious cosmological constant problem. The role of the Higgs in reheating and baryogenesis is discussed.

View PDFchevron_right

Cited by

Conformal GUT inflation, proton lifetime and non-thermal leptogenesis
Paulo Moniz

The European Physical Journal C

In this paper, we generalize Coleman–Weinberg (CW) inflation in grand unified theories (GUTs) such as $$\text {SU}(5)$$SU(5) and $$\text {SO}(10)$$SO(10) by means of considering two complex singlet fields with conformal invariance. In this framework, inflation emerges from a spontaneously broken conformal symmetry. The GUT symmetry implies a potential with a CW form, as a consequence of radiative corrections. The conformal symmetry flattens the above VEV branch of the CW potential to a Starobinsky plateau. As a result, we obtain $$n_{s}\sim 1-\frac{2}{N}$$ns∼1-2N and $$r\sim \frac{12}{N^2}$$r∼12N2 for $$N\sim $$N∼ 50–60 e-foldings. Furthermore, this framework allow us to estimate the proton lifetime as $$\tau _{p}\lesssim 10^{40}$$τp≲1040 years, whose decay is mediated by the superheavy gauge bosons. Moreover, we implement a type I seesaw mechanism by weakly coupling the complex singlet, which carries two units of lepton number, to the three generations of singlet right handed neutr...

View PDFchevron_right
Symmetron and de Sitter attractor in a teleparallel model of cosmology
H. Mohseni Sadjadi

Journal of Cosmology and Astroparticle Physics

In the teleparallel framework of cosmology, a quintessence with nonminimal couplings to the scalar torsion and a boundary term is considered. A conformal coupling to matter density is also taken into account. It is shown that the model can describe the onset of cosmic acceleration after an epoch of matter dominated era, where dark energy is negligible, via Z 2 symmetry breaking. While the conformal coupling holds the Universe in a state with zero dark energy density in the early epoch, the non-minimal couplings lead the Universe to a stable state with de Sitter expansion at the late time.

View PDFchevron_right
Palatini inflation in models with an R2 term
Ignatios Antoniadis

Journal of Cosmology and Astroparticle Physics

The Starobinsky model, considered in the framework of the Palatini formalism, in contrast to the metric formulation, does not provide us with a model for inflation, due to the absence of a propagating scalar degree of freedom that can play the role of the inflaton. In the present article we study the Palatini formulation of the Starobinsky model coupled, in general nonminimally, to scalar fields and analyze its inflationary behavior. We consider scalars, minimally or nonminimally coupled to the Starobinsky model, such as a quadratic model, the induced gravity model or the standard Higgs-like inflation model and analyze the corresponding modifications favorable to inflation. In addition we examine the case of a classically scale-invariant model driven by the Coleman-Weinberg mechanism. In the slow-roll approximation, we analyze the inflationary predictions of these models and compare them to the latest constraints from the Planck collaboration. In all cases, we find that the effect of the R 2 term is to lower the value of the tensor-to-scalar ratio.

View PDFchevron_right
Classical and quantum cosmology of K-essentially modified $$R^2$$ R 2 and pure $$R^p$$ R p gravity
Kiyoshi Shiraishi

General Relativity and Gravitation

We present a gravitational action with a modified higher order term of a combination of scalar curvature and Lagrangian density of a scalar field. This type of models has been considered first by Cruz-Dombriz et al. The classical and quantum cosmologies governed by the modified action are studied. Models described by a positive-definite action and a pure arbitrary-powered scalar curvature action without the standard Einstein-Hilbert term are also investigated. We show some particular cases in which exact solutions can be obtained.

View PDFchevron_right
Unification of inflation and dark matter in the Higgs–Starobinsky model
Phongpichit Channuie

The European Physical Journal C

In this work, we propose unified picture of inflation and dark matter in the Higgs-Starobinsky (HS) model. As pointed out in the literature, Starobinsky R 2 inflation is induced by quantum correction effect from the large Higgscurvature (graviton) coupling. We start with non-minimal coupling HS action in Jordan frame. We then transform the Jordan frame action into the Einstein one using the conformal transformation. The inflation potential is derived from the gravitational action of non-minimal-Higgs coupling and Starobinsky term in Einstein frame where the R 2 term is dominated in the inflationary phase of the universe. For model of inflation, we compute the inflationary parameters and confront them with Planck 2015 data. We discover that the predictions of the model are in excellent agreement with the Planck analysis. In addition, we find that the HS model is equivalent to a scalar singlet dark matter (SSDM) or Higgsportal model. The renormalization group equations (RGEs) of HS scenario with standard model at one-loop level is qualitatively analyzed. By using the solutions of parameter spaces from RGE analysis, the coupling constants of the HS model will be verified and can be used to constrain the SSDM using dark matter relic abundance.

View PDFchevron_right
580 California St., Suite 400
San Francisco, CA, 94104
© 2025 Academia. All rights reserved