Subleading Isgur–Wise function of Λb→Λc1 using QCD sum rules

Abstract Subleading Isgur–Wise form factor τ ( v · v ′) at O (1/m Q ) for Λ b → Λ c 1 1/2,3/2 weak transition is calculated by using the QCD sum rules in the framework of the heavy quark effective theory (HQET), where Λ 1/2 c 1 and Λ 3/2 c 1 are the orbitally excited charmed baryon doublet with J P =(1 − /2,3 − /2). We consider the subleading contributions from the weak current matching in the HQET. The interpolating currents with transverse covariant derivative are adopted for Λ 1/2 c 1 and Λ 3/2 c 1 in the analysis. The slope parameter ρ 2 in linear approximation of τ is obtained to be ρ 2 =2.76 and the interception to be τ (1)=−1.27 GeV.