Electroweak hadron structure within a point-form approach

TL;DR

This paper introduces a relativistic point-form approach to calculate electroweak form factors of few-body bound states, exemplified by B to D* semileptonic decay, and compares results with experimental data.

Contribution

It develops a novel relativistic point-form method for electroweak form factors and demonstrates its application to heavy meson decays, connecting to the Isgur-Wise function.

Findings

Form factors derived from the approach match experimental data.

The method unambiguously extracts form factors from the invariant transition amplitude.

In the heavy-quark limit, form factors reduce to the Isgur-Wise function.

Abstract

We present a relativistic point-form approach for the calculation of electroweak form factors of few-body bound states. As an example, the transition form factors for the semileptonic weak decay $B\to D^*e\bar \nu_e$ are discussed and it is sketched how they can be extracted unambiguously from the invariant transition amplitude that describes the process. It is shown how these form factors go over into one universal function, the Isgur-Wise function in the heavy-quark limit, $m_Q\to \infty$, and comparison with the available experimental data is made.