Chiral dynamics, S-wave contributions and angular analysis in D→ππℓν

• Published in: The European physical journal. C, Particles and fields Particles and fields, 2017-07, Vol.77 (7)
• Main Authors: Shi, Yu-Ji, Wang, Wei, Zhao, Shuai
• Format: Article
• Language: English
• Subjects: Astronomy; Astrophysics and Cosmology; Elementary Particles; Hadrons; Heavy Ions; Measurement Science and Instrumentation; Nuclear Energy; Nuclear Physics; Physics; Physics and Astronomy; Quantum Field Theories; Quantum Field Theory; Regular Article - Theoretical Physics; String Theory
• ISSN: 1434-6044; 1434-6052
• DOI: 10.1140/epjc/s10052-017-5016-1

We present a theoretical analysis of the D - → π + π - ℓ ν ¯ and D ¯ 0 → π + π 0 ℓ ν ¯ decays. We construct a general angular distribution which can include arbitrary partial waves of π π . Retaining the S-wave and P-wave contributions we study the branching ratios, forward–backward asymmetries and a few other observables. The P-wave contribution is dominated by ρ 0 resonance, and the S-wave contribution is analyzed using the unitarized chiral perturbation theory. The obtained branching fraction for D → ρ ℓ ν , at the order 10 - 3 , is consistent with the available experimental data. The S-wave contribution has a branching ratio at the order of 10 - 4 , and this prediction can be tested by experiments like BESIII and LHCb. Future measurements can also be used to examine the π – π scattering phase shift.