Factorization of Heavy-to-Light Baryonic Transitions in SCET

TL;DR

This paper uses soft-collinear effective theory to analyze heavy-to-light baryonic form factors at large recoil, revealing symmetry relations, factorization properties, and energy scaling laws, with implications for understanding baryonic transitions in QCD.

Contribution

It demonstrates the factorization and symmetry properties of heavy-to-light baryonic form factors in SCET, including the derivation of their energy dependence and suppression effects.

Findings

Form factors obey heavy quark and large energy symmetries.

Factorization into soft, collinear, and hard components is established.

Form factors scale as rac{a}{E^2} with energy.

Abstract

In the framework of the soft-collinear effective theory, we demonstrate that the leading-power heavy-to-light baryonic form factors at large recoil obey the heavy quark and large energy symmetries. Symmetry breaking effects are suppressed by ${\Lambda}/m_{b}$ or $\Lambda/E$, where $\Lambda$ is the hadronic scale, $m_b$ is the $b$ quark mass and $E\sim m_b$ is the energy of light baryon in the final state. At leading order, the leading power baryonic form factor $\xi_{\Lambda,p}(E)$, in which two hard-collinear gluons are exchanged in the baryon constituents, can factorize into the soft and collinear matrix elements convoluted with a hard-kernel of order $\alpha_s^2$. Including the energy release dependence, we derive the scaling law $\xi_{\Lambda,p}(E)\sim \Lambda^2 /E^2$. We also find that this form factor $\xi_{\Lambda}(E)$ is numerically smaller than the form factor governed by soft processes, although the latter is formally power-suppressed.