2018/06/30 by Naoyuki Haba, Hiroyuki Umeeda, Toshifumi Yamada · 2 citations
Physics and Astronomy · #Amplitude #CP violation #D meson #Gauge (firearms) #Gauge boson #Meson #Neutrino Physics Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #Quantum chromodynamics #Standard Model (mathematical formulation) #hep-ph
paper · pdf · doi:10.1007/jhep10(2018)006
18 pages, 2 tables and 3 figures; v3: Discussion on the effect of $SU(3)$ flavor symmetry breaking is added
openalex created_date 2018/06/13 · arxiv created 2018/09/25 · openalex publication_date 2018/10/01 · arxiv updated 2018/11/14 · openalex updated_date 2026/08/05
A bstract Since the standard model contribution is virtually absent, any observation of direct CP violation in the Cabibbo-favored charmed meson decays would be evidence of new physics. In this paper, we conduct a quantitative study on direct CP violation in D 0 → K − π + , D s + → ηπ + and D s + → η ′ π + decays in the SU(2) L ×SU(2) R ×U(1) B − L gauge extension of the standard model. In the model, direct CP violation arises mainly from the interference between the decay amplitude coming from the SM left-left current operators and that from the right-right current operators induced by W R + gauge boson exchange. Interestingly, the strong phase between the two amplitudes is evaluable, since it stems from difference in QCD corrections to the left-left and right-right current operators, which is a short-distance QCD effect given by ∼ (αs(MWL2)/4π ) log (MWR2/MWL2) <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mo>∼</mml:mo> <mml:mfenced> <mml:mrow> <mml:msub> <mml:mi>α</mml:mi> <mml:mi>s</mml:mi> </mml:msub> <mml:mfenced> <mml:msubsup> <mml:mi>M</mml:mi> <mml:msub> <mml:mi>W</mml:mi> <mml:mi>L</mml:mi> </mml:msub> <mml:mn>2</mml:mn> </mml:msubsup> </mml:mfenced> <mml:mo>/</mml:mo> <mml:mn>4</mml:mn> <mml:mi>π</mml:mi> </mml:mrow> </mml:mfenced> <mml:mo>log</mml:mo> <mml:mfenced> <mml:mrow> <mml:msubsup> <mml:mi>M</mml:mi> <mml:msub> <mml:mi>W</mml:mi> <mml:mi>R</mml:mi> </mml:msub> <mml:mn>2</mml:mn> </mml:msubsup> <mml:mo>/</mml:mo> <mml:msubsup> <mml:mi>M</mml:mi> <mml:msub> <mml:mi>W</mml:mi> <mml:mi>L</mml:mi> </mml:msub> <mml:mn>2</mml:mn> </mml:msubsup> </mml:mrow> </mml:mfenced> </mml:math> . We assess the maximal direct CP violation in the above decays in the SU(2) L × SU(2) R × U(1) B − L model. Additionally, we present a correlation between direct CP violation in these modes and one in K → ππ decay parametrized by ϵ ′, since W R + gauge boson has a sizable impact on the latter.