Does the QCD scale vary in time?

✍ Scribed by Harald Fritzsch

• Publisher: Elsevier Science
• Year: 2004
• Tongue: English
• Weight: 320 KB
• Volume: 133
• Category: Article
• ISSN: 0920-5632
• DOI: 10.1016/j.nuclphysbps.2004.04.149

✦ Synopsis

Last year I talked at this meeting about a possible time dependende of the QCD coupling constant as. This year I shall look into this problem once more, without fully repeating the arguments given last year. Astrophysical indications that the fine structure constant has undergone a small time variation during the cosmological evolution are discussed within the framework of the standard model of the electroweak and strong interactions and of grand unification. A variation of the electromagnetic coupling constant could either be generated by a corresponding time variation of the unified coupling constant or by a time variation of the unification scale, of by both. The various possibilities, differing substantially in their implications for the variation of low energy physics parameters like the nuclear mass scale, are discussed. The case in which the variation is caused by a time variation of the unification scale is of special interest. It is supported in addition by recent hints towards a time change of the proton-electron mass ratio.