gNDΛc from QCD sum rules

The NDΛc coupling constant is evaluated in a full QCD sum rule calculation. We study the Borel sum rule for the three point function of one pseudoscalar one nucleon and one Λc current up to order seven in the operator product expansion. The Borel transform is performed with respect to the nucleon and Λc momenta, which are taken to be equal, whereas the momentum q2 of the pseudoscalar vertex is taken to be zero. This coupling constant is relevant in the meson cloud description of the nucleon which has been recently used to explain exotic events observed by the H1 and ZEUS Collaborations at HERA.