Phenomenological Study Of Charm Meson Decay And CP Violation

The study of charm sector including the subject of CP violation has been being payedmuch attention since the discovering of charm quark in 1974. We presently know Cabibbo-Kobayashi-Maskawa (CKM) mechanism embedded in the Standard Model (SM) is the mainsource of CP violation in the quark sector. The impressive agreement between results fromthe s-quark and the b-quark sectors calls for further checks in less tested areas. The recentdiscussions concerning the leptonic decays of D and Ds mesons, about a possible disagree-ment between lattice results and experimental data, suggest that the charm sector has notbeen explored as extensively as other quarks. Arround this issue we carried out a series ofstudy.In the chapter 1, we would like to introduce the knowledge of D0D0 mixing and itspresent experimental status. Then using the same oscillation theory, We discuss the possiblesearching for theΛ(?)Λoscillations for coherentΛΛproduction in J/ψâ†'ΛΛdecay process.The sensitivity of measurement ofΛ(?)Λoscillation in the external field at BES-III experimentis considered. With one year's luminosity at BES-III, we can set an upper limit ofδm < 10(?)15MeV at 90% confidence level, corresponding to about 10(?)6 s ofΛ(?)Λoscillation time. Theseconsiderations indicate an alternative way to probe the (?)B = 2 amplitude in addition toneutron oscillation experiments.In the chapter 2, we mainly focus on the CP violation of D meson sector by construct-ing the new CP violating observables. One way is using one D decay without quantumcorrelation in which the T violating triple-product correlation is examined. The other wayis exploiting quantum correlation by double D decay. Firstly, we build CP-violating ob-servables inψ(3770)â†'D Dˉâ†'(V1V2)(V3V4) to isolate specific New Physics e(?)ects in thecharm sector. Secondly, we also consider the case ofψ(3770)â†'D Dˉâ†'(V1V2)(KÏ€) decays,which provide a new way to measure the strong phase di(?)erenceδbetween Cabibbo-favoredand doubly-Cabibbo suppressed D decays required in the determination of the CKM angleγ. Neglecting the systematics, we give a first rough estimate of the sensitivities of these measurements at BES-III with an integrated luminosity of 20 fb(?)1 atψ(3770) peak and ata future SuperÏ„-charm factory with a luminosity of 1035 cm(?)2s(?)1.In the chapter 3, we study CP violation inΛc+â†'BP andΛ+câ†'BV decays, where B,Pand V denote a light spin-12 baryon, pseudoscalar and a vector meson respectively. In theseprocesses the idea of T odd CP violating triple-product(TP) correlations are also examined.The genuine CP violating observables which are composed of the helicity amplitudes oc-curring in the angular distribution are constructed. Experimentally, by performing a fullangular analysis it is shown how one may extract the helicity amplitudes and then obtainthe TP asymmetries. We estimate the TP asymmetries inΛc decays to be negligible in thestandard model making these processes an excellent place to look for new physics. Takinga two Higgs doublet model (2HDM), as an example of new physics, we show that large TPasymmetries are possible in these decays. At the end, we discuss how BES-III and SuperÏ„-Charm experiments will be sensitive to these CP violating signals inΛ+c decays.In the chapter 4, we would like to provide a model for P(?) wave Dl4 form factors.Experimentally the upcoming large D data samples at BES-III in Beijing will provide a greatopportunity to perform the analysis of semileptonic D decay, which makes the new light oftheoretical study necessary. Combining the chiral symmetry and heavy quark symmetry, theheavy meson chiral perturbation theory (HMχPT) is constructed. We firstly use it to writeone-loop form factor and then we write the tree level result in resonance chiral perturbationtheory (RChPT) to match these two results. At last we try to unitarize using dispersionrelations to expand it to higher energy region.In the chapter 5, we calculated the KÏ€rescattering e(?)ects in the Dâ†'KÏ€lνdecayusing heavy hadron chiral perturbation theory.In the chapter 6, we give the summary and outlook before the bibliography, publicationsin the master period and acknowledgements.