A comprehensive study on the semileptonic decay of heavy flavor mesons
Lu Zhang, Xian-Wei Kang, Xin-Heng Guo, Ling-Yun Dai, Tao Luo, Chao Wang
Abstract
A bstract The semileptonic decay of heavy flavor mesons offers a clean environment for extraction of the Cabibbo-Kobayashi-Maskawa (CKM) matrix elements, which describes the CP-violating and flavor changing process in the Standard Model. The involved form factors where the dynamical information is encoded play an essential role in achieving any conclusive statement. That is, the knowledge of the form factors should be under good control, requiring one to examine more observables in addition to the branching fraction. In this paper, we provide the mean value and the q 2 -dependent shape for further observables [differential decay distribution ( d Γ/ dq 2 ), forward-backward asymmetry $$ \left({\mathcal{A}}_{FB}^{ls}\right) $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mfenced> <mml:msubsup> <mml:mi>A</mml:mi> <mml:mi>FB</mml:mi> <mml:mi>ls</mml:mi> </mml:msubsup> </mml:mfenced> </mml:math> , longitudinal $$ \left({P}_L^l\right) $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mfenced> <mml:msubsup> <mml:mi>P</mml:mi> <mml:mi>L</mml:mi> <mml:mi>l</mml:mi> </mml:msubsup> </mml:mfenced> </mml:math> and transverse $$ \left({P}_T^l\right) $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mfenced> <mml:msubsup> <mml:mi>P</mml:mi> <mml:mi>T</mml:mi> <mml:mi>l</mml:mi> </mml:msubsup> </mml:mfenced> </mml:math> polarization of a charged lepton, longitudinal polarization of a vector meson in the final state $$ \left({F}_L^l(V)\right) $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mfenced> <mml:mrow> <mml:msubsup> <mml:mi>F</mml:mi> <mml:mi>L</mml:mi> <mml:mi>l</mml:mi> </mml:msubsup> <mml:mfenced> <mml:mi>V</mml:mi> </mml:mfenced> </mml:mrow> </mml:mfenced> </mml:math> , leptonic convexity parameter $$ \left({C}_F^l\right) $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mfenced> <mml:msubsup> <mml:mi>C</mml:mi> <mml:mi>F</mml:mi> <mml:mi>l</mml:mi> </mml:msubsup> </mml:mfenced> </mml:math> , and trigonometric moments $$ \left({W}_i^l\right) $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mfenced> <mml:msubsup> <mml:mi>W</mml:mi> <mml:mi>i</mml:mi> <mml:mi>l</mml:mi> </mml:msubsup> </mml:mfenced> </mml:math> in the decay of D ( s ) and B ( s ) to P / Vl + ν l ( l = e , μ or τ )], based on the predictions of the relevant form factors from the covariant light-front quark model. P and V denote the pseudoscalar and vector meson, respectively. As a comparison, we find a good agreement with the results from the covariant confining quark model and the relativistic quark model in the literature. As it has been observed that the $$ {P}_L^l $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>P</mml:mi> <mml:mi>L</mml:mi> <mml:mi>l</mml:mi> </mml:msubsup> </mml:math> and $$ {F}_L^l(V) $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>F</mml:mi> <mml:mi>L</mml:mi> <mml:mi>l</mml:mi> </mml:msubsup> <mml:mfenced> <mml:mi>V</mml:mi> </mml:mfenced> </mml:math> are crucial quantities to discriminate various New Physics models, the reexamination of these observables from a different method is also essential and necessary.