Particle decay in post inflationary cosmology

Abstract

We study scalar particle decay during the radiation and matter dominated epochs of a standard cosmological model. An adiabatic approximation is introduced that is valid for degrees of freedom with typical wavelengths much smaller than the particle horizon ($\propto$~Hubble radius) at a given time. We implement a non-perturbative method that includes the cosmological expansion and obtain a cosmological Fermi's Golden Rule that enables one to compute the decay law of a parent particle of mass $m_1$, along with the build up of the population of daughter particles of mass $m_2$. The survival probability of the decaying particle is $P(t)=e^{-{\tilde{\Gamma }}_k(t)t}$ with ${\tilde{\Gamma }}_k(t)$ being an \emph{effective momentum and time dependent decay rate}. It features a transition time scale $t_{nr}$ between the relativistic and non-relativistic regimes and for $k\ne 0$ is always smaller than the analogous rate in Minkowski spacetime, as a consequence of (local) time dilation and the cosmological redshift. For $t\ll t_{nr}$ the decay law is a "stretched exponential" $P(t)=e^{-(t/t^{\ast }{)}^{3/2}}$, whereas for the non-relativistic stage with $t\gg t_{nr}$, we find $P(t)=e^{-{\Gamma }_{0}t}(t/t_{nr}{)}^{{\Gamma }_0{t}_{nr}/2}$. The Hubble time scale $\propto 1/H(t)$ introduces an energy uncertainty $\Delta E\sim H(t)$ which relaxes the constraints of kinematic thresholds. This opens new decay channels into heavier particles for $2\pi E_k(t)H(t)\gg 4m_2^2-m_1^2$, with $E_k(t)$ the (local) comoving energy of the decaying particle. As the expansion proceeds this channel closes and the usual two particle thresholds restrict the decay kinematics.

arXiv commentmore comments. published version

References in corpus (43)

• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Determination of Cosmological Parameters
• Planck 2015 results. XIII. Cosmological parameters
• Nine-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Final Maps and Results
• CP violating decays in leptogenesis scenarios
• Big-Bang Nucleosynthesis and Hadronic Decay of Long-Lived Massive Particles
• Primordial Nucleosynthesis: from precision cosmology to fundamental physics
• The Primordial Lithium Problem
• Hadronic Decay of Late-Decaying Particles and Big-Bang Nucleosynthesis
• Big Bang Nucleosynthesis Constraints on Hadronically and Electromagnetically Decaying Relic Neutral Particles
• Did Something Decay, Evaporate, or Annihilate during Big Bang Nucleosynthesis?
• Big Bang Nucleosynthesis as a Probe of New Physics
• A fresh look at linear cosmological constraints on a decaying dark matter component
• Strongest model-independent bound on the lifetime of Dark Matter
• Cosmological Simulations of Decaying Dark Matter: Implications for Small-scale Structure of Dark Matter Halos
• Cosmological particle production and the precision of the WKB approximation
• Lifetime of a massive particle in a de Sitter universe
• Super-Adiabatic Particle Number in Schwinger and de Sitter Particle Production
• GUT baryogenesis after preheating: numerical study of the production and decay of X-bosons
• Non-universal BBN bounds on electromagnetically decaying particles
• Particle decay during inflation: self-decay of inflaton quantum fluctuations during slow roll
• On the Time Dependence of Adiabatic Particle Number
• Particle decay in inflationary cosmology
• Particle decays and stability on the de Sitter universe
• Particle creation and particle number in an expanding universe
• Lyman-alpha Forest Constraints on Decaying Dark Matter
• Inflaton Decay in De Sitter Spacetime
• A loophole to the universal photon spectrum in electromagnetic cascades: application to the "cosmological lithium problem"
• On the Perturbative Stability of Quantum Field Theories in de Sitter Space
• Entanglement entropy in particle decay
• WIMP Dark Matter from Gravitino Decays and Leptogenesis
• Constraints on the Cosmological Relativistic Energy Density
• Cosmological constraints to dark matter with two- and many-body decays
• Effects of Long-lived 10 MeV Scale Sterile Neutrino on Primordial Elemental Abundances and Effective Neutrino Number
• Searching for sterile neutrinos from $\pi$ and $K$ decays
• Gravitational Particle Creation in a Stiff Matter Dominated Universe
• Weak Gravitational Lensing as a Method to Constrain Unstable Dark Matter
• Leptogenesis through direct inflaton decay to light particles
• Breaking Be: a sterile neutrino solution to the cosmological lithium problem
• Decay of a Massive Particle in a Stiff Matter Dominated Universe
• Decaying Massive Particle in Matter and Radiation Dominated Eras
• Baryogenesis by B - L generation due to superheavy particle decay
• Particle decay in expanding Friedmann-Robertson-Walker universes
• Creation of quantized particles, gravitons and scalar perturbations by the expanding universe

Cited by in corpus (13)

• Ionization of Gravitational Atoms
• Gravitational production of nearly thermal fermionic Dark Matter
• Reheating via gravitational particle production in kination epoch
• On the origin of entropy of gravitationally produced dark matter: the entanglement entropy
• Brownian Axion-like particles
• Fermionic decay of a massive scalar in the early Universe
• Cosmological decay of Higgs-like scalars into a fermion channel
• Quantum decay in renormalizable field theories: quasiparticle formation, Zeno and anti-Zeno effects
• Interaction rates in cosmology: heavy particle production and scattering
• Ultralight dark matter or dark radiation cosmologically produced from infrared dressing
• Particle physics processes in cosmology through an effective Minkowski space formulation and the limitations of the method
• Reheating in the kination epoch via multi-channel decay of gravitationally created massive scalars
• Condensate decay in a radiation dominated cosmology