Seeing Higher-Dimensional Grand Unification In Primordial Non-Gaussianities

Abstract

The observed low-energy values of the $SU(3)\times SU(2)\times U(1)$ gauge couplings, extrapolated via the minimal Standard Model Renormalization Group evolution, hint at the exciting possibility of a Grand Unified Theory (GUT) at $M_U\sim 10^{14}$ GeV --- a scale, however, too high to probe directly via collider searches. Fortunately, since the Hubble scale H can be as high as $5\times 10^{13}$ GeV $\sim M_U$ during the inflationary era, such GUT scale states can be cosmologically produced at that time and leave direct on-shell signatures such as their masses and spins, via primordial non-Gaussianity (NG). We explore this possibility in one of its simplest realizations given by the extra-dimensional framework of orbifold GUTs, in which proton decay can be straightforwardly suppressed to be within the stringent bounds. Here, along with the massive GUT states there must also be H-mass spin-2 Kaluza-Klein (KK) gravitons, collectively giving rise to striking NG signatures. In our set-up we localize the inflaton on one of the boundaries of an extra dimension. The inflationary vacuum energy can readily lead to formation of a horizon in the bulk, where the KK modes then form a continuum above a mass gap of $\sim \mathcal{O}(H)$. We find that the optimal case for observable NG signals is when the extra dimension is stabilized close to the onset of this horizon, ensuring a discrete KK spectrum such that the lightest KK modes can be cosmologically produced without significant Boltzmann suppressions. Although we mostly focus on the case where there is no higher-dimensional cosmological constant, we also obtain considerable holographic insights from the ${\text{AdS}}_5/{\text{CFT}}_4$ correspondence when such a cosmological constant is included.

arXiv commentv1: 30+10 pages, 6 figures; v2: discussion added at the end of subsection 4.3, reference added, conclusions unchanged, journal version

References in corpus (72)

• A Large Mass Hierarchy from a Small Extra Dimension
• An Alternative to Compactification
• The Large N Limit of Superconformal Field Theories and Supergravity
• Non-Gaussian features of primordial fluctuations in single field inflationary models
• Modulus Stabilization with Bulk Fields
• Modeling the fifth dimension with scalars and gravity
• The Effective Field Theory of Inflation
• Quantum Contributions to Cosmological Correlations
• Locally Localized Gravity
• Primordial Non-Gaussianities from Inflation Models
• Quasi-Single Field Inflation and Non-Gaussianities
• Planck 2015 results. XVII. Constraints on primordial non-Gaussianity
• Chaotic inflation on the brane
• Gauge Unification in Higher Dimensions
• Radion Dynamics and Electroweak Physics
• Bent Domain Walls as Braneworlds
• Triplet-doublet Splitting, Proton Stability and Extra Dimension
• Proton stability in grand unified theories, in strings, and in branes
• Measuring the Small-Scale Power Spectrum of Cosmic Density Fluctuations Through 21 cm Tomography Prior to the Epoch of Structure Formation
• Signatures of Supersymmetry from the Early Universe
• On Soft Limits of Inflationary Correlation Functions
• On non-gaussianities in single-field inflation
• Gravitational waves from inflation on the brane
• Gauge Symmetry Reduction from the Extra Space $S^1/Z_2$
• Effective field theory approach to quasi-single field inflation and effects of heavy fields
• Non-Gaussianity as a Particle Detector
• Inflation in the five-dimensional universe with an orbifold extra dimension
• Brane-world creation and black holes
• Search for Proton Decay via $p\to e^{+}{\pi }^0$ and $p\to {\mu }^{+}{\pi }^0$ in 0.31 megaton$\cdot$years exposure of the Super-Kamiokande Water Cherenkov Detector
• Inflation and Gauge Hierarchy in Randall-Sundrum Compactification
• Quasi-Single Field Inflation with Large Mass
• Schwinger-Keldysh Diagrammatics for Primordial Perturbations
• Inflation and Large Internal Dimensions
• Boundary Inflation
• Prospects for Cosmological Collider Physics
• Imprint of inflation on galaxy shape correlations
• Standard Model Background of the Cosmological Collider
• Loop Corrections to Standard Model Fields in Inflation
• Heavy-Lifting of Gauge Theories By Cosmic Inflation
• Standard Model Mass Spectrum in Inflationary Universe
• Partially Massless Fields During Inflation
• Imprints of Massive Primordial Fields on Large-Scale Structure
• Quasi Single Field Inflation in the non-perturbative regime
• On the Inflationary Perturbations of Massive Higher-Spin Fields
• Neutrino Signatures in Primordial Non-Gaussianities
• Holographic models of de Sitter QFTs
• Light Particles with Spin in Inflation
• Galaxy Bispectrum from Massive Spinning Particles
• Multitracing Anisotropic Non-Gaussianity with Galaxy Shapes
• 4D Models of Scherk-Schwarz GUT Breaking via Deconstruction
• Non-Gaussian Enhancements of Galactic Halo Correlations in Quasi-Single Field Inflation
• Radion on the de Sitter brane
• The radion in brane cosmology
• Imprints of Spinning Particles on Primordial Cosmological Perturbations
• Detecting higher spin fields through statistical anisotropy in the CMB and galaxy power spectra
• Scale-Dependent Galaxy Bias from Massive Particles with Spin during Inflation
• Dynamics of a Stabilized Radion and Duality
• Unique Fingerprints of Alternatives to Inflation in the Primordial Power Spectrum
• Grand Unification in Higher Dimensions
• Wave Function of the Radion in the dS and AdS Brane Worlds
• Imprints of Oscillatory Bispectra on Galaxy Clustering
• Transdimensional physics and inflation
• Biasing and the search for primordial non-Gaussianity beyond the local type
• TASI 2004 Lectures: To the Fifth Dimension and Back
• Intrinsic galaxy alignment from angular dependent primordial non-Gaussianity
• Detecting higher spin fields through statistical anisotropy in the CMB bispectrum
• Can Inflating Braneworlds be Stabilized?
• Constraints on long-lived, higher-spin particles from galaxy bispectrum
• Hybrid Quasi-Single Field Inflation
• Possible Signatures of Inflationary Particle Content: Spin-2 Fields
• Exploring extra dimensions through inflationary tensor modes
• De Sitter Quantum Loops as the origin of Primordial Non-Gaussianities

Cited by in corpus (41)

• Linking the Singularities of Cosmological Correlators
• In Search of Large Signals at the Cosmological Collider
• Probing P and CP Violations on the Cosmological Collider
• Boostless Cosmological Collider Bootstrap
• Cosmological Collider Physics and the Curvaton
• Cosmological Bootstrap in Slow Motion
• The Scalar Chemical Potential in Cosmological Collider Physics
• A Cosmological Higgs Collider
• Bootstrapping Multi-Field Inflation: non-Gaussianities from light scalars revisited
• Large Spin-2 Signals at the Cosmological Collider
• Cutting Rule for Cosmological Collider Signals: A Bulk Evolution Perspective
• Helical Inflation Correlators: Partial Mellin-Barnes and Bootstrap Equations
• Bootstrapping One-Loop Inflation Correlators with the Spectral Decomposition
• Gravitational Production of Superheavy Dark Matter and Associated Cosmological Signatures
• Cosmological Signatures of Superheavy Dark Matter
• Closed-Form Formulae for Inflation Correlators
• Classical Cosmological Collider Physics and Primordial Features
• Cosmological Collider Signatures of Massive Vectors from Non-Gaussian Gravitational Waves
• Galaxy imaging surveys as spin-sensitive detector for cosmological colliders
• The Cosmological Bootstrap: Spinning Correlators from Symmetries and Factorization
• Disentangling mass spectra of multiple fields in cosmological collider
• Heavy Spinning Particles from Signs of Primordial Non-Gaussianities: Beyond the Positivity Bounds
• Axion Isocurvature Collider
• Searching for Cosmological Collider in the Planck CMB Data
• Continuous Spectrum on Cosmological Collider
• Primordial trispectrum from kSZ tomography
• An Effective Cosmological Collider
• Analytic Formulae for Inflationary Correlators with Dynamical Mass
• Perturbative unitarity in quasi-single field inflation
• Cosmology from the kinetic polarized Sunyaev Zel'dovich effect
• Uncorrelated Compensated Isocurvature Perturbations from kSZ Tomography
• Fingerprints of a Non-Inflationary Universe from Massive Fields
• Non-Gaussianity from $X,Y$ gauge bosons in Cosmological Collider Physics
• Confinement in de Sitter Space and the Swampland
• Grand Unification at the Cosmological Collider with Chemical Potential
• Charged Loops at the Cosmological Collider with Chemical Potential
• The cosmological collider in $R^2$ inflation
• Magnetic Fields from Compensated Isocurvature Perturbations
• Strongly Coupled Sectors in Inflation: Gapless Theories and Unparticles
• Strongly Coupled Sectors in Inflation: Gapped Theories of Unparticles
• On the importance of heavy fields in pseudo-scalar inflation