Breaking CPT by mixed noncommutativity

Irina Mocioiu, Maxim Pospelov, Radu Roiban

Research output: Contribution to journalArticlepeer-review

34 Scopus citations


The mixed component of the noncommutative parameter θ0 μM, where μ=0,1,2,3 and M is an extra dimensional index, may violate four-dimensional CPT invariance. We calculate one- and two-loop induced couplings of θμ5 with the four-dimensional axial vector current and with the CPT odd dim=6 operators starting from five-dimensional Yukawa and U(1) theories. The resulting bounds from clock comparison experiments place a stringent constraint on θμ5, |θμ5|-1/25×1011 GeV. Orbifold projection and/or localization of fermions on a 3-brane lead to CPT-conserving physics, in which case the constraints on θμ5 are softened.

Original languageEnglish (US)
Article number107702
JournalPhysical Review D
Issue number10
StatePublished - 2002

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics


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