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
为解决热电偶时间常数常规标定方法周期长、成本高、无法在线标定的问题,介绍了一种基于回路电流阶跃响应(Loop Current Step Response,LCSR)的热电偶时间常数原位在线标定方法(简称“LCSR法”),重点阐述了LCSR法的基本原理和标定方法,...为解决热电偶时间常数常规标定方法周期长、成本高、无法在线标定的问题,介绍了一种基于回路电流阶跃响应(Loop Current Step Response,LCSR)的热电偶时间常数原位在线标定方法(简称“LCSR法”),重点阐述了LCSR法的基本原理和标定方法,开展了实验室环境下热风洞法与LCSR法时间常数实验对比研究,实验表明:LCSR法标定周期远低于热风洞法,且时间常数标定结果基本一致。最后,探讨了温度畸变真实环境下原位在线标定的测试应用前景。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.
文摘为解决热电偶时间常数常规标定方法周期长、成本高、无法在线标定的问题,介绍了一种基于回路电流阶跃响应(Loop Current Step Response,LCSR)的热电偶时间常数原位在线标定方法(简称“LCSR法”),重点阐述了LCSR法的基本原理和标定方法,开展了实验室环境下热风洞法与LCSR法时间常数实验对比研究,实验表明:LCSR法标定周期远低于热风洞法,且时间常数标定结果基本一致。最后,探讨了温度畸变真实环境下原位在线标定的测试应用前景。
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.
