Browsing by Author "Ramirez, Carlos A."

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    New physics effects in D+ -> K- pi(+) pi(+)
    (IOP PUBLISHING LTD, 2015) Delepine, David; Faisel, Gaber; Ramirez, Carlos A.
    In this paper, we study the Cabibbo favored three body non-leptonic D+ -> K-pi(+)pi(+) decay. We show that the corresponding direct charge parity (CP) asymmetry is extremely tiny in the framework of the Standard Model (SM) and is out of experimental range. Motivated by this result we extend the study of the CP asymmetries to include a generic model where the CPV weak phase equals 20 degrees in a(2), a model with extra gauge bosons within left-right (LR) grand unification models and a model with a charged Higgs boson. We show that the generic model can strongly enhance CP asymmetries-reaching up to 30% in some regions of the Dalitz plots and still being compatible with the existing experimental limit on the total CP asymmetry in this channel. Large CP asymmetries can be achieved in the non-manifest LR models where partial CP asymmetries up to a few % can be reached and the experimental limit on the total CP asymmetry already can be used to constraint these LR SM extensions. For the two Higgs doublets models the CP asymmetries are of order 10(-3).
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    Observation of CP violation in D-0 -> K-pi(+) as a smoking gun for new physics
    (AMER PHYSICAL SOC., 2013) Delepine, David; Faisel, Gaber; Ramirez, Carlos A.
    In this paper, we study the Cabibbo favored nonleptonic D-0 decays into K-pi(+) decays. First we show that, within the Standard Model (SM), the corresponding charge conjugation and parity (CP) asymmetry is strongly suppressed and out of the experimental range, even taking into account the large strong phases coming from final state interactions. We show also that although new physics models with extra sequential generation can enhance the CP asymmetry by a few orders of magnitude, the resulting CP asymmetry is still far from the experimental range. The most sensitive new physics models to this CP asymmetry come from nonmanifest left-right models, where a CP asymmetry up to 10% can be reached, and the general two-Higgs model extension of the SM, where a CP asymmetry of order 10(-2) can be obtained without being in contradiction with the experimental constraints on these models. DOI: 10.1103/PhysRevD.87.075017