The cosmological constant: Plus CA change, plus C`est La Meme Chose
Conference
·
OSTI ID:572776
Recent measurements of the cosmological parameters have renewed interest in the cosmological constant {Lambda}. I briefly review the current status of these measurements and the corresponding arguments for and against cosmological models with non-zero {Lambda}. I outline a scenario which attempts to incorporate non-zero vacuum energy into the framework of particle physics, based on an ultra-light pseudo-Nambu-Goldstone boson. With global spontaneous symmetry breaking scale f {approx_equal} 10{sup 18} GeV and explicit breaking scale comparable to MSW neutrino masses, M {approximately} 10{sup -3} eV, such a field, which acquires a mass M{sub {phi}} {approximately} M{sup 2}/f {approximately} H{sub 0}, would have become dynamical at recent epochs and currently dominate the energy density of the universe. The field acts as an effective cosmological constant for several expansion times and then relaxes into a condensate of coherent non-relativistic bosons. Such a model can reconcile dynamical estimates of the density parameter, {Omega}{sub m} {approximately} 0.2, with a spatially flat universe, and can yield an expansion age H{sub 0}t{sub 0} {approx_equal} 1 while remaining consistent with limits from gravitational lens statistics.
- Research Organization:
- Fermi National Accelerator Lab., Batavia, IL (United States)
- Sponsoring Organization:
- USDOE Office of Energy Research, Washington, DC (United States)
- DOE Contract Number:
- AC02-76CH03000
- OSTI ID:
- 572776
- Report Number(s):
- FNAL/C--95/261-A; CONF-9506433--; ON: DE98051977; BR: KA HEP
- Country of Publication:
- United States
- Language:
- English
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