Towards a microscopic construction of flavour vacua from a space-time foam model

Abstract

The effect on flavour oscillations of simple expanding background space-times, motivated by some D-particle foam models, is calculated for a toy-model of bosons with flavour degrees of freedom. The presence of D-particle defects in the space-time, which can interact non trivially (via particle capture) with flavoured particles in a flavour non-preserving way, generates mixing in the effective field theory of low-energy string excitations. Moreover, the recoil of the D-particle defect during the capture/scattering process implies Lorentz violation, which however may be averaged to zero in isotropic D-particle populations, but implies non-trivial effects in correlators. Both features imply that the flavoured mixed state sees a non-trivial flavour (Fock-space) vacuum of a type introduced earlier by Blasone and Vitiello in a generic context of theories with mixing. We discuss the orthogonality of the flavour vacua to the usual Fock vacua and the effect on flavour oscillations in these backgrounds. Furthermore we analyse the equation of state of the Flavour vacuum, and find that, for slow expansion rates induced by D particle recoil, it is equivalent to that of a cosmological constant. Some estimates of these novel non-perturbative contribution to the vacuum energy are made. The contribution vanishes if the mass difference and the mixing angle of the flavoured states vanish.

27 pages RevTex, 2 eps figures incorporated

References in corpus (4)

• Neutrino mixing as a source of dark energy
• Decoherence induced CPT violation and entangled neutral mesons
• Relativistic Modified Newtonian Dynamics from String Theory?
• Methods of approaching decoherence in the flavour sector due to space-time foam

Cited by in corpus (6)

• Time Delays of Strings in D-particle Backgrounds and Vacuum Refractive Indices
• Dark energy and particle mixing
• Flavour Condensates in Brane Models and Dark Energy
• CPT Violation and Decoherence in Quantum Gravity
• Non-abelian gauge structure in neutrino mixing
• Non-extensive statistics in stringy space-time foam models and entangled meson states