Interpreting cosmological vacuum decay

Journal Article · Thu Sep 15 04:00:00 EDT 2005 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PhysRevD.72.063516· OSTI ID:20713533

Alcaniz, J S; Lima, J A.S. ^[1]

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1. Departamento de Astronomia, Observatorio Nacional, 20921-400 Rio de Janeiro - RJ (Brazil)

The cosmological vacuum decay scenario recently proposed by Wang and Meng [Classical Quantum Gravity 22, 283 (2005)] is rediscussed. From thermodynamic arguments it is found that the {epsilon} parameter quantifying the vacuum decay rate must be positive in the presence of particle creation. If there is no particle creation, the proper mass of Cold Dark Matter (CDM) particles is necessarily a time-dependent quantity, scaling as m(t)=m{sub o}a(t){sup {epsilon}}. By considering the presence of baryons in the cosmological scenario, it is also shown that their dynamic effect is to alter the transition redshift z{sub *} (the redshift at which the Universe switches from decelerating to accelerating expansion), predicting values of z{sub *} compatible with current estimates based on type Ia supernova. In order to constrain the {omega}{sub m}-{epsilon} plane, a joint statistical analysis involving the current supernovae observations, gas mass fraction measurements in galaxy clusters and CMB data is performed. At 95% c.l. it is found that the vacuum decay rate parameter lies on the interval {epsilon}=0.06{+-}0.10. The possibility of a vacuum decay into photons is also analyzed. In this case, the energy density of the radiation fluid scales as {rho}{sub r}={rho}{sub ro}a{sup -4+{epsilon}}, and its temperature evolution law obeys T(t)=T{sub o}a(t){sup {epsilon}}{sup /4-1}.

• OSTI ID: 20713533
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 6 Vol. 72; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BARYONS
COSMIC RADIATION
COSMOLOGY
DECAY
ENERGY DENSITY
GALAXY CLUSTERS
GRAVITATION
NONLUMINOUS MATTER
PHOTONS
QUANTUM GRAVITY
RADIOWAVE RADIATION
RELICT RADIATION
SUPERNOVAE
TIME DEPENDENCE
UNIVERSE