Bounding effective parameters in the chiral Lagrangian for excited heavy mesons

We use recent experimental data on charmed mesons to constrain three coupling constants in the effective lagrangian describing the interactions of excited heavy-light mesons with light pseudoscalar mesons at order m Q . Predictions in the beauty sector are also derived. The coupling constants and the mass parameters in effective Lagrangians which reproduce QCD in specific limits represent important input parameters for the description of the hadron processes. Therefore their determination, either by theoretical approaches or by phenomenological analyses, is relevant for the use of the related effective theory. The case of the effective Lagrangian describing the strong interactions of heavy-light hadrons with the octet of pseudo Goldstone bosons is not an exception, and it is noticeable that data recently collected at the B factories and at the Fermilab Tevatron can constrain a few of such parameters, thus allowing to exploit this theoretical framework to make, for example, predictions that can be tested at the new experiments. This note is devoted to such a discussion. The heavy quark chiral effective theory is constructed starting from the spin-flavour symmetry occurring in QCD for hadrons comprising a single heavy quark, in the infinite heavy quark mass limit, and from the chiral symmetry valid in the massless limit for the light quarks [1]. The heavy quark spin-flavour symmetry allows to classify heavy Qq̄ mesons into doublets labeled by the value of the angular momentum sl of the light degrees of freedom: sl = sq̄+l, sq̄ being the light antiquark spin and l the orbital angular momentum of the light degrees of freedom relative to the heavy quark [2]. The lowest lying Qq̄ mesons correspond to l = 0, then sl = 1 2 − ; this doublet comprises two states with spin-parity J = (0, 1): P = D(s)(B(s)) and P ∗ = D (s)(B ∗ (s)) mesons in case of charm (beauty) heavy quark, respectively. For l = 1 it could be either sl = 1 2 + or sl = 3 2 + . The two corresponding doublets have J = (0, 1) and J = (1, 2). We denote the members of the J sl = (0 , 1)1/2 doublet as (P ∗ 0 , P ′ 1) and those of the J P sl = (1, 2)3/2 doublet as (P1, P ∗ 2 ), with P = D,Ds, B,Bs. The negative and positive parity doublets can be respectively described by the fields Ha, Sa and T μ a , a = u, d, s being a light flavour index: Ha = 1 + v / 2 [P ∗ aμγ μ − Paγ5] (1)