General Analysis of Dark Radiation in Sequestered String Models

Abstract

We perform a general analysis of axionic dark radiation produced from the decay of the lightest modulus in the sequestered LARGE Volume Scenario. We discuss several cases depending on the form of the Kahler metric for visible sector matter fields and the mechanism responsible for achieving a de Sitter vacuum. The leading decay channels which determine dark radiation predictions are to hidden sector axions, visible sector Higgses and SUSY scalars depending on their mass. We show that in most of the parameter space of split SUSY-like models squarks and sleptons are heavier than the lightest modulus. Hence dark radiation predictions previously obtained for MSSM-like cases hold more generally also for split SUSY-like cases since the decay channel to SUSY scalars is kinematically forbidden. However the inclusion of string loop corrections to the Kahler potential gives rise to a parameter space region where the decay channel to SUSY scalars opens up, leading to a significant reduction of dark radiation production. In this case, the simplest model with a shift-symmetric Higgs sector can suppress the excess of dark radiation $\Delta N_{eff}$ to values as small as 0.14, in perfect agreement with current experimental bounds. Depending on the exact mass of the SUSY scalars all values in the range 0.14 $\lesssim \Delta N_{eff}\lesssim$ 1.6 are allowed. Interestingly dark radiation overproduction can be avoided also in the absence of a Giudice-Masiero coupling.

30 pages, 5 figures

References in corpus (13)

• A new determination of the primordial He abundance using the HeI 10830A emission line: cosmological implications
• Moduli-Induced Gravitino Problem
• Non-thermal Dark Matter and the Moduli Problem in String Frameworks
• SUSY Breaking in Local String/F-Theory Models
• Jumping Through Loops: On Soft Terms from Large Volume Compactifications
• Dark Radiation in LARGE Volume Models
• Systematics of String Loop Corrections in Type IIB Calabi-Yau Flux Compactifications
• Higgs Mass and Unnatural Supersymmetry
• Towards Realistic String Vacua From Branes At Singularities
• Sequestered de Sitter String Scenarios: Soft-terms
• SusyHD: Higgs mass Determination in Supersymmetry
• Dark Radiation predictions from general Large Volume Scenarios
• Dark Radiation in Anisotropic LARGE Volume Compactifications

Cited by in corpus (16)

• Physics potential of the International Axion Observatory (IAXO)
• Global Embedding of Fibre Inflation Models
• ${\alpha }^{\prime }$ Inflation: Moduli Stabilisation and Observable Tensors from Higher Derivatives
• Out of the Swampland with Multifield Quintessence?
• Moduli Stars
• Reheating and Dark Radiation after Fibre Inflation
• Categorisation and Detection of Dark Matter Candidates from String/M-theory Hidden Sectors
• The Fate of Dense Scalar Stars
• Systematics of type IIB moduli stabilisation with odd axions
• Affleck-Dine Baryogenesis in Type IIB String Models
• Cosmology in the presence of multiple light moduli
• High Energy Sphalerons for Baryogenesis at Low Temperatures
• Fibre inflation and precision CMB data
• The 3.5 keV Line from Stringy Axions
• Dark Radiation and the Hagedorn Phase
• Non-thermal Axion Dark Radiation and Constraints