Reconciling BICEP2 and Planck results with right-handed Dirac neutrinos in the fundamental representation of grand unified<i>E</i><sub>6</sub>

Anchordoqui, Luis A.; Goldberg, Haim; Huang, X. T.; Vlček, B.

doi:10.1088/1475-7516/2014/06/042

Cited by 9 publications

(11 citation statements)

References 106 publications

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“…In fact light neutrinos are relativistic at decoupling time and they behave like radiation: changing N eff changes the composition of the energy density, changing therefore the early expansion history. This has been called "dark radiation" but it can mimic several other physical effects see e.g., [49][50][51][52][53][54][55][56][57][58][59][60]. For example a model such as the one proposed in [51] of a thermalized massless boson, has a ∆N eff between ∼ 0.57 and 0.39 depending on the decoupling temperature [3].…”

Section: Survey Z Effmentioning

confidence: 99%

The trouble with $H_0$

Bernal,

Verde,

Riess

2016

Preprint

114

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We perform a comprehensive cosmological study of the H 0 tension between the direct local measurement and the model-dependent value inferred from the Cosmic Microwave Background. With the recent measurement of H 0 this tension has raised to more than 3 σ. We consider changes in the early time physics without modifying the late time cosmology. We also reconstruct the late time expansion history in a model independent way with minimal assumptions using distance measurements from Baryon Acoustic Oscillations and Type Ia Supernovae, finding that at z < 0.6 the recovered shape of the expansion history is less than 5% different than that of a standard ΛCDM model. These probes also provide a model insensitive constraint on the low-redshift standard ruler, measuring directly the combination r s h where H 0 = h × 100 Mpc −1 km/s and r s is the sound horizon at radiation drag (the standard ruler), traditionally constrained by CMB observations. Thus r s and H 0 provide absolute scales for distance measurements (anchors) at opposite ends of the observable Universe. We calibrate the cosmic distance ladder and obtain a model-independent determination of the standard ruler for acoustic scale, r s . The tension in H 0 reflects a mismatch between our determination of r s and its standard, CMB-inferred value. Without including high-Planck CMB polarization data (i.e., only considering the "recommended baseline" low-polarisation and temperature and the high temperature data), a modification of the early-time physics to include a component of dark radiation with an effective number of species around 0.4 would reconcile the CMB-inferred constraints, and the local H 0 and standard ruler determinations. The inclusion of the "preliminary" high-Planck CMB polarisation data disfavours this solution.

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Section: Survey Z Effmentioning

confidence: 99%

The trouble with $H_0$

Bernal,

Verde,

Riess

2016

Preprint

114

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“…In Fig. 2 we compare the aftermath of the multiparameter fit of {Ω b h 2 , Ω CDB h 2 , Θ s , τ, n s , A s , r, N eff , m ν } to the data reported by the Planck and BICEP2 collaborations (Dvorkin et al 2014;Anchordoqui et al 2014a). Clearly, a higher effective number of relativistic species can relieve the tension between Planck and BICEP2 results.…”

Section: B-mode Power Spectrum Pmentioning

confidence: 96%

Constraints on cosmological parameters from Planck and BICEP2 data

Anchordoqui¹

2014

Preprint

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We show that the tension introduced by the detection of large amplitude gravitational wave power by the BICEP2 experiment with temperature anisotropy measurements by the Planck mission is alleviated in models where extra light species contribute to the effective number of relativistic degrees of freedom. We also show that inflationary models based on S-dual potentials are in agreement with Planck and BICEP2 data. Fitting ΛCDM + r to Planck and BICEP2 dataMeasurements of the cosmic microwave background (CMB) and large scale structure (LSS) indicate that we live in a spatially-flat, accelerating, infinite universe composed of 4% of baryons (b), 26% of (cold) dark matter (CDM), and 70% of dark energy (Λ). These observations also reveal that the universe has tiny ripples of adiabatic, scale-invariant, Gaussian density perturbations. The favored ΛCDM model implicitly includes the hypothesis of a very early period in which the scale factor of the universe expands exponentially: a ∝ e Ht , where H = ȧ/a is the Hubble parameter (see e.g. Baumann 2009). If the interval of exponential expansion satisfies ∆t > N/H, with N above about 50 to 60, a small casually connected region can grow sufficiently to accommodate the observed homogeneity and isotropy, to dilute any overdensity of magnetic monopoles, and to flatten the spatial hyper-surfaces (i.e., Ω ≡ 8πρ 3M Pl H 2 → 1, where M PL = G −1/2 is the Planck mass and ρ the energy density; throughout we use natural units, c = = 1). Quantum fluctuations during this inflationary period can explain the observed cosmological perturbations.Fluctuations are created quantum mechanically on subhorizon scales with a spectrum of wavenumbers k. (A mode k is called superhorizon when k < aH and subhorizon when k > aH.) While comoving scales, k −1 , remain constant the comoving Hubble radius, (aH) −1 , shrinks quasi-exponentially during inflation (driving the universe toward flatness) and the perturbations exit the horizon. Causal physics cannot act on superhorizon perturbations and they freeze until horizon re-entry at late times. A mode exiting the horizon can then be described 1

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“…with g B = 2 for each real vector field and g F = 2 for each spin-1 2 Weyl field [63]. The coefficient r(T) is unity for leptons, two for photon contributions, and is the ratio s(T)/s SB for the quark-gluon plasma.…”

Section: As Indicated In Tablementioning

confidence: 99%

Hubble Hullabaloo and String Cosmology

Anchordoqui

2020

Preprint

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Reconciling BICEP2 and Planck results with right-handed Dirac neutrinos in the fundamental representation of grand unifiedE₆

Cited by 9 publications

References 106 publications

The trouble with $H_0$

The trouble with $H_0$

Constraints on cosmological parameters from Planck and BICEP2 data

Hubble Hullabaloo and String Cosmology

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Reconciling BICEP2 and Planck results with right-handed Dirac neutrinos in the fundamental representation of grand unifiedE6

Cited by 9 publications

References 106 publications

The trouble with $H_0$

The trouble with $H_0$

Constraints on cosmological parameters from Planck and BICEP2 data

Hubble Hullabaloo and String Cosmology

Contact Info

Product

Resources

About

Reconciling BICEP2 and Planck results with right-handed Dirac neutrinos in the fundamental representation of grand unifiedE₆