A Universe without Weak Interactions

Harnik, Roni ; Kribs, Graham D. ; Perez, Gilad

Stanford Linear Accelerator Center

关键词: Standard Model;    Cosmological Constant;    Weak Interactions Phenomenology-Hep,Astro, Hepph, Hepth;    Stars;    Universe;   

DOI  :  10.2172/878715
RP-ID  :  SLAC-PUB-11795
RP-ID  :  AC02-76SF00515
RP-ID  :  878715

美国|英语

来源: UNT Digital Library

【 摘 要 】

A universe without weak interactions is constructed that undergoes big-bang nucleosynthesis, matter domination, structure formation, and star formation. The stars in this universe are able to burn for billions of years, synthesize elements up to iron, and undergo supernova explosions, dispersing heavy elements into the interstellar medium. These definitive claims are supported by a detailed analysis where this hypothetical ''Weakless Universe'' is matched to our Universe by simultaneously adjusting Standard Model and cosmological parameters. For instance, chemistry and nuclear physics are essentially unchanged. The apparent habitability of the Weakless Universe suggests that the anthropic principle does not determine the scale of electroweak breaking, or even require that it be smaller than the Planck scale, so long as technically natural parameters may be suitably adjusted. Whether the multi-parameter adjustment is realized or probable is dependent on the ultraviolet completion, such as the string landscape. Considering a similar analysis for the cosmological constant, however, we argue that no adjustments of other parameters are able to allow the cosmological constant to raise up even remotely close to the Planck scale while obtaining macroscopic structure. The fine-tuning problems associated with the electroweak breaking scale and the cosmological constant therefore appear to be qualitatively different from the perspective of obtaining a habitable universe.