Tensor form factors of P→ P, S, V and A transitions within standard and covariant light-front approaches * * Supported by the National Natural Science Foundation of China (11875122) and the Program for Innovative Research Team in University of Henan Province (19IRTSTHN018)

Qin Chang,Li-Ting Wang,Xiao-Lin Wang

doi:10.1088/1674-1137/44/8/083105

Qin Chang, Li-Ting Wang + Show 1 more

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https://doi.org/10.1088/1674-1137/44/8/083105

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Abstract

We investigate the tensor form factors of , and A transitions within the standard light-front (SLF) and the covariant light-front (CLF) quark models (QMs). The self-consistency and Lorentz covariance of CLF QM are analyzed via these quantities, and the effects of zero-mode are discussed. For the and A transitions, besides the inconsistency between the results extracted via longitudinal and transverse polarization states, which is caused by the residual -dependent spurious contributions, we find and analyze a “novel” self-consistence problem of the traditional CLF QM, caused by different strategies for dealing with the trace term in CLF matrix element. A possible solution to the problems of traditional CLF QM is discussed and confirmed numerically. Finally, the theoretical predictions for the tensor form factors of some and ( ) induced and A transitions are updated within the CLF QM with a self-consistent scheme.

Highlights

The heavy-to-light exclusive weak decays provide a fertile ground for testing the Standard Model (SM) and looking for physics beyond it
Comparing our results for P → V (A) transition, Eqs. (56-58), with the ones obtained in the previous work [81, 82], Eqs. (91-93), which are collected in the appendix A, we find that our result for T1CLF, Eq (56), is exactly the same as the one in Refs. [81,82], Eq (91), the results for T2C,3LF are different
It is exactly what we expect due to the following facts: (1) the covariant light-front (CLF) quark models (QMs) has employed the LF vertex functions which can only be extracted by mapping the CLF result to the standard light-front (SLF) one; (ii) the zero-mode contributions are not taken into account in the SLF result, the SLF result is only corresponding to the valence contribution in the CLF QM

Summary

Introduction

The heavy-to-light exclusive weak decays provide a fertile ground for testing the Standard Model (SM) and looking for physics beyond it. [81, 82]; the corrected theoretical results are further applied to the phenomenological studies of some radiative B and Bs decays [82] and radiative D and Ds decays [83] It is worth checking these previous results of tensor form factors, and evaluating the transitions which are not considered before. In our previous works [85,86,87], the self-consistence problem has been studied in detail via fP,V,A and form factors of P → (P, V ) and V → V transitions associated with the (axial)vector current, and the modified type-II correspondence scheme as a solution to the selfconsistence problem [84] is carefully tested. Some previous theoretical results are collected in appendix A for convenience of discussion and comparison, and the values of input parameters used in the computation are collected in appendix B

Theoretical Framework and Results

Theoretical results in the SLF QM

Theoretical results in the CLF QM

Numerical results and discussions

Summary