Details

Autor(en) / Beteiligte

• Gaillard, M. K.
• Gavela, M. B.
• Houtz, R.
• Quilez, P.
• del Rey, R.

Titel

Color unified dynamical axion

Ist Teil von

• The European physical journal. C, Particles and fields, 2018-11, Vol.78 (11), p.1-21, Article 972

Ort / Verlag

Berlin/Heidelberg: Springer Berlin Heidelberg

Erscheinungsjahr

2018

Link zum Volltext

Quelle

SpringerLink

Beschreibungen/Notizen

• We consider an enlarged color sector which solves the strong CP problem via new massless fermions. The spontaneous breaking of a unified color group into QCD and another confining group provides a source of naturally large axion mass m a due to small size instantons. This extra source of axion mass respects automatically the alignment of the vacuum, ensuring a low-energy CP-conserving vacuum. The mechanism does not appeal to a Z 2 “mirror” copy of the SM, nor does it require any fine-tuning of the axion-related couplings at the unification scale. There is no very light axion and uncharacteristically the lighter spectrum contains instead sterile fermions. The axion scale f a can be naturally brought down to a few TeV, with an exotic spectrum of colored pseudoscalars lighter than this scale, observable at colliders exclusively via strong interactions. The { m a , f a } parameter space which allows a solution of the strong CP problem is thus enlarged well beyond that of invisible axion models.