English

CP violation in lepton number violating semihadronic decays of $K, D, D_s, B, B_c$

High Energy Physics - Phenomenology 2014-05-21 v2

Abstract

We study the CP violation in lepton number violating meson decays M±1±2±MM^{\pm} \to \ell_1^{\pm} \ell_2^{\pm} M^{' \mp}, where MM and MM^{'} are pseudoscalar mesons, M=K,D,Ds,B,BcM=K, D, D_s, B, B_c and M=π,K,D,DsM^{'}=\pi, K, D, D_s, and the charged leptons are 1,2=e,μ\ell_1, \ell_2 = e, \mu. It turns out that the CP-violating difference S(M)[Γ(M12M+)Γ(M+1+2+M)]S_{-}(M) \equiv [\Gamma(M^- \to \ell_1^- \ell_2^- M^{' +})-\Gamma(M^+ \to \ell_1^+ \ell_2^+ M^{' -})] can become appreciable when two intermediate on-shell Majorana neutrinos NjN_j (j=1,2j=1,2) participate in these decays. Our calculations show that the asymmetry becomes largest when the masses of N1N_1 and N2N_2 are almost degenerate, i.e., when the mass difference ΔMN\Delta M_N becomes comparable with the (small) decay widths ΓN\Gamma_N of these neutrinos: ΔMN≫̸ΓN\Delta M_N \not\gg \Gamma_N. We show that in such a case, the CP ratio ACP(M)[Γ(M12M+)Γ(M+1+2+M)]/[Γ(M12M+)+Γ(M+1+2+M)]{\cal A}_{CP}(M) \equiv [\Gamma(M^- \to \ell_1^- \ell_2^- M^{' +})-\Gamma(M^+ \to \ell_1^+ \ell_2^+ M^{' -})]/[\Gamma(M^- \to \ell_1^- \ell_2^- M^{' +})+\Gamma(M^+ \to \ell_1^+ \ell_2^+ M^{' -})] becomes a quantity 1\sim 1. The observation of CP violation in these decays would be consistent with the existence of the well-motivated ν\nuMSM model with two almost degenerate heavy neutrinos in the mass range between MN0.1M_N \sim 0.1-10110^1 GeV.

Keywords

Cite

@article{arxiv.1403.2555,
  title  = {CP violation in lepton number violating semihadronic decays of $K, D, D_s, B, B_c$},
  author = {Gorazd Cvetic and C. S. Kim and Jilberto Zamora-Saa},
  journal= {arXiv preprint arXiv:1403.2555},
  year   = {2014}
}

Comments

19 pages, 8 figures; v2: a new Table (I); minor changes in the text; new references [5,31,32]; ref.[19] extended; to appear in Phys.Rev.D