## Search

Now showing items 1-10 of 12

#### First moment of the flavour octet nucleon parton distribution function using lattice QCD

(2015-01-15)

We perform a lattice computation of the flavour octet contribution to the average quark momentum in a nucleon, $\la x\ra^{(8)}_{\mu^2 = 4 \gev^2}$. In particular, we fully take the disconnected contributions into account ...

#### Excited State Effects in Nucleon Matrix Element Calculations

(2011-12-13)

We perform a high-statistics precision calculation of nucleon matrix elements using an open sink method allowing us to explore a wide range of sink-source time separations. In this way the influence of excited states of ...

#### Sigma terms and strangeness content of the nucleon with $Nf=2+1+1$ twisted mass fermions

(2012-11-19)

We investigate excited state contaminations in a direct computation of the nucleon $\sigma$-terms. This is an important source of systematic effects that needs to be controlled besides the light quark mass dependence and ...

#### Precision Study of Excited State Effects in Nucleon Matrix Elements

(2011-08-04)

We present a dedicated analysis of the influence of excited states on the calculation of nucleon matrix elements. This calculation is performed at a fixed value of the lattice spacing, volume and pion mass that are typical ...

#### Nucleon matrix elements with $N_f=2+1+1$ maximally twisted fermions

(2011-01-28)

We present the first lattice calculation of nucleon matrix elements using four dynamical flavors. We use the $N_f=2+1+1$ maximally twisted mass formulation. The renormalization is performed non-perturbatively in the ...

#### Nucleon form factors and moments of generalized parton distributions using $N_f=2+1+1$ twisted mass fermions

(2013-03-24)

We present results on the axial and the electromagnetic form factors of the nucleon, as well as, on the first moments of the nucleon generalized parton distributions using maximally twisted mass fermions. We analyze two ...

#### Evaluation of disconnected quark loops for hadron structure using GPUs

(2013-09-09)

A number of stochastic methods developed for the calculation of fermion loops are investigated and compared, in particular with respect to their efficiency when implemented on Graphics Processing Units (GPUs). We assess ...

#### Disconnected quark loop contributions to nucleon observables in lattice QCD

(2013-10-23)

We perform a high statistics calculation of disconnected fermion loops on Graphics Processing Units for a range of nucleon matrix elements extracted using lattice QCD. The isoscalar electromagnetic and axial vector form ...

#### Nucleon Structure using lattice QCD

(2013-03-27)

A review of recent nucleon structure calculations within lattice QCD is presented. The nucleon excited states, the axial charge, the isovector momentum fraction and helicity distribution are discussed, assessing the methods ...

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

(2013-11-24)

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 $\sigma$-terms are casting light on the origin of the nucleon ...