The quark contents of the nucleon and their implication for dark matter search

Abstract

We present results concerning the light and strange quark contents of the nucleon using $N_f=2+1+1$ flavours of maximally twisted mass fermions. The corresponding $σ$-terms are casting light on the origin of the nucleon mass and their values are important to interpret experimental data from direct dark matter searches. We discuss our strategy to estimate systematic uncertainties arising in our computations. Our preliminary results for the $σ-$terms read $σ_{πN} = 37(2.6)(24.7) \mev$ and $σ_s=28(8)(10) \mev$. We present our recent final analysis of the $y_N$ parameter and found $y_N=0.135(46)$ including systematics\cite{Alexandrou:2013nda}.

7 pages, 6 figures, talk given at the 31st International Symposium on Lattice Field Theory (Lattice 2013), July 29-August 3 2013, Mainz, Germany