Search for CP violation in D ⁺ → ϕπ ⁺ and $D_s^{+}\to K_S^0{\pi^{+}}$ decays

Abstract

A search for CP violation in D ⁺ → ϕπ ⁺ decays is performed using data collected in 2011 by the LHCb experiment corresponding to an integrated luminosity of 1.0 fb⁻¹ at a centre of mass energy of 7 TeV. The CP -violating asymmetry is measured to be (−0.04 ± 0.14 ± 0.14)% for candidates with K ⁻ K ⁺ mass within 20 MeV/c ² of the ϕ meson mass. A search for a CP -violating asymmetry that varies across the ϕ mass region of the D ⁺ → K ⁻ K ⁺ π ⁺ Dalitz plot is also performed, and no evidence for CP violation is found. In addition, the CP asymmetry in the $D_s^{+}\to K_{\mathrm{S}}^0{\pi^{+}}$ decay is measured to be (0.61 ± 0.83 ± 0.14)%.