12,000

We have over 12,000 students, from over 100 countries, within one of the safest campuses in the UK

93%

93% of Lancaster students go into work or further study within six months of graduating

Home > Research > Publications & Outputs > Cosmological constraints on unparticles as cont...
View graph of relations

« Back

Cosmological constraints on unparticles as continuous mass particles.

Research output: Contribution to journalJournal article

Published

Journal publication date16/03/2009
JournalJournal of Cosmology and Astroparticle Physics
Journal number3
Volume2009
Pages19
Original languageEnglish

Abstract

We study the cosmological constraints on unparticle interactions and the temperature of the Universe for the case where unparticle states can be modelled as continuous mass particles with lifetime 1s. By considering thermal background quark decay to continuous mass scalars via a scalar operator of dimension dU, we show that the condition that the Universe is not dominated by scalars at nucleosynthesis imposes a lower bound on the scale of the interaction of the unparticle sector, with MU 20−2600 TeV for ΛU 1 TeV, 1.1 ≤ dU ≤ 2.0 and 2 ≤ dBZ ≤ 4. The existence of a long-lived scalar sector also imposes an upper bound on the temperature of the Universe during radiation-domination, which can be as low as a TeV for MU close to its lower bound.