Search

We are investigating the direct determination and non-perturbative renormalisation of gluon matrix elements. Such quantities are sensitive to ultra– violet fluctuations, and are in general statistically noisy. To obtain statistically significant results, we extend an earlier application of the Feynman–Hellmann theorem to gluonic matrix elements to calculate a renormalisation factor in the RI – MOM scheme, in the quenched case. This work demonstrates that the Feynman–Hellmann method is capable of providing a feasible option for calculating gluon quantities.

Extending the SU(3) flavour symmetry breaking expansion from up, down and strange sea quark masses to partially quenched valence quark masses allows an extrapolation to the charm quark mass. This approach leads to a determination of charmed quark hadron masses and decay constants. We describe our recent progress and give preliminary results in particular with regard to the recently discovered doubly charmed baryon (the Ξcc++) by the LHCb Collaboration.