Towards understanding of the inclusive vs exclusive puzzle in the $|V_{cb}|$ determinations

TL;DR

This paper discusses the role of lattice calculations in resolving the longstanding discrepancy in determining the CKM matrix element |V_{cb}|, focusing on inclusive decay rate computations and their current challenges.

Contribution

It provides an overview of the current status and future prospects of lattice-based methods for calculating inclusive decay rates related to |V_{cb}| determination.

Findings

Lattice calculations are crucial for understanding the |V_{cb}| puzzle.

Current formalism for inclusive decay rate computation is under development.

Phase-space approximation and finite volume effects are key challenges.

Abstract

Lattice calculation may play an important role to understand the cause of the long-standing puzzle among the determination of $|V_{cb}|$. The key element is the computation of the inclusive decay rate, for which the formalism is under development. The method has its own problem: the approximation of the phase-space factor and finite volume effect. I discuss the current status of such study and future prospects.