Eur. Phys. J. A (2018) 54: 146
https://doi.org/10.1140/epja/i2018-12582-6

Regular Article - Theoretical Physics

Exclusive decays within the effective field theory framework

¹ Institut für Kernphysik, Johannes Gutenberg-Universität, D-55099, Mainz, Germany
² Petersburg Nuclear Physics Institute, 188300, Gatchina, St. Petersburg, Russia

^* e-mail: mail.to.nikolai@gmail.com

Received: 7 May 2018
Accepted: 9 August 2018
Published online: 10 September 2018

Abstract

We study hadronic decays within the effective field theory framework. We consider the colour-singlet and colour-octet contributions and study their properties using (p)NRQCD effective theory. We show that infrared singularities in collinear integrals of the colour-singlet amplitudes can be absorbed into the renormalisation of the colour-octet matrix elements. The heavy quark spin symmetry allows us to establish a relation between the colour-octet matrix elements and to define the spin symmetry breaking corrections which are free from infrared singularities. We apply obtained results for a phenomenological description of the branching fractions.