We present a systematic light-cone QCD sum rule study of the exclusive rare radiative decay Ab → Aγ and rare semileptonic decay Ab→ Al＋ l- within the framework of the standard model. Although some light-cone sum r...We present a systematic light-cone QCD sum rule study of the exclusive rare radiative decay Ab → Aγ and rare semileptonic decay Ab→ Al＋ l- within the framework of the standard model. Although some light-cone sum rule （LCSR） studies on these rare processes can be found in different literatures, it is necessary to reanalyze them systematically for the reason that either the baryonic distribution amplitudes are improved or different interpolating currents for the Ab baryon may lead to quite different results. In addition, the rare process Ab →Aγ has not yet been analyzed by LCSR with the Ioffe-type current. Taking all these reasons into account, we perform LCSR calculations of both the processes with two types of interpolating currents. Our calculations show that the choice of the interpolating current for the Ab baryon can affect the predictions significantly, especially for the rare radiative decay process.展开更多
In this study,D→P(π,K) helicity form factors(HFFs) are investigated by applying the QCD light-cone sum rule(LCSR) approach.The calculation accuracy is up to the next-to-leading order(NLO) gluon radiation correction ...In this study,D→P(π,K) helicity form factors(HFFs) are investigated by applying the QCD light-cone sum rule(LCSR) approach.The calculation accuracy is up to the next-to-leading order(NLO) gluon radiation correction of twist-(2,3) distribution amplitude.The resultant HFFs at a large recoil point are Pt,0π(0)=0.688-0.024+0.020 and Pt,0K(O)=0.780-0.029+0.024,in which the contributions from the three particles of the leading order(LO) are so small that they can be safely neglected.The maximal contribution of the NLO gluon radiation correction for Pt,0r,K(0) is less than3%.After extrapolating the LCSR predictions for these HFFs to the whole q2-region,we obtain the decay widths for semileptonic decay processes D→Plvl,which are consistent with the BES-Ⅲ collaboration predictions within error limits.After considering the D+/D0-meson lifetime,we give the branching fractions of D→Plvl with l=e,μ;our predictions also agree with the BES-Ⅲ collaboration results within error limits,especially for the D→πlvl decay process.Finally,we present the forward-backward asymmetry AFBl(q2) and lepton convexity parameter CFl(q2),and further calculate the mean value of these two observations,<AFBl> and {CFl),which may provide a way to test those HFFs in future experiments.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos. 11205242, 10975184, 11105222, and 11105223
文摘We present a systematic light-cone QCD sum rule study of the exclusive rare radiative decay Ab → Aγ and rare semileptonic decay Ab→ Al＋ l- within the framework of the standard model. Although some light-cone sum rule （LCSR） studies on these rare processes can be found in different literatures, it is necessary to reanalyze them systematically for the reason that either the baryonic distribution amplitudes are improved or different interpolating currents for the Ab baryon may lead to quite different results. In addition, the rare process Ab →Aγ has not yet been analyzed by LCSR with the Ioffe-type current. Taking all these reasons into account, we perform LCSR calculations of both the processes with two types of interpolating currents. Our calculations show that the choice of the interpolating current for the Ab baryon can affect the predictions significantly, especially for the rare radiative decay process.
基金Supported in part by the National Science Foundation of China(11765007)the National Natural Science Foundation of China(11947302)+1 种基金the Project of Guizhou Provincial Department of Science and Technology(KY[2017]1089,No.KY[2019]1171)the China Postdoctoral Science Foundation(2019TQ0329)。
文摘In this study,D→P(π,K) helicity form factors(HFFs) are investigated by applying the QCD light-cone sum rule(LCSR) approach.The calculation accuracy is up to the next-to-leading order(NLO) gluon radiation correction of twist-(2,3) distribution amplitude.The resultant HFFs at a large recoil point are Pt,0π(0)=0.688-0.024+0.020 and Pt,0K(O)=0.780-0.029+0.024,in which the contributions from the three particles of the leading order(LO) are so small that they can be safely neglected.The maximal contribution of the NLO gluon radiation correction for Pt,0r,K(0) is less than3%.After extrapolating the LCSR predictions for these HFFs to the whole q2-region,we obtain the decay widths for semileptonic decay processes D→Plvl,which are consistent with the BES-Ⅲ collaboration predictions within error limits.After considering the D+/D0-meson lifetime,we give the branching fractions of D→Plvl with l=e,μ;our predictions also agree with the BES-Ⅲ collaboration results within error limits,especially for the D→πlvl decay process.Finally,we present the forward-backward asymmetry AFBl(q2) and lepton convexity parameter CFl(q2),and further calculate the mean value of these two observations,<AFBl> and {CFl),which may provide a way to test those HFFs in future experiments.
