Baryonic and mesonic 3-point functions with open spin indices

We have implemented a new way of computing three-point correlation functions. It is based on a factorization of the entire correlation function into two parts which are evaluated with open spin- (and to some extent flavor-) indices. This allows us to estimate the two contributions simultaneously for many different initial and final states and momenta, with little computational overhead. We explain this factorization as well as its efficient implementation in a new library which has been written to provide the necessary functionality on modern parallel architectures and on CPUs, including Intel's Xeon Phi series.Comment: 7 pages, 5 figures, Proceedings of Lattice 201

The Disjunctive Conception of Perceiving

John McDowell's conception of perceptual knowledge commits him to the claim that if I perceive that P then I am in a position to know that I perceive that P. In the first part of this essay, I present some reasons to be suspicious of this claim - reasons which derive from a general argument against 'luminosity' - and suggest that McDowell can reject this claim, while holding on to almost all of the rest of his conception of perceptual knowledge, by supplementing his existing disjunctive conception of experience with a new disjunctive conception of perceiving. In the second part of the essay, I present some reasons for thinking that one's justification, in cases of perceptual knowledge, consists not in the fact that one perceives that P but in the fact that one perceives such-and-such. I end by suggesting that the disjunctive conception of perceiving should be understood as a disjunctive conception of perceiving such-and-such

Hyperon couplings from Nf=2+1N_f = 2 + 1 lattice QCD

We compute various (generalized) isovector charges of the octet baryons. These include $g_A$, $g_T$ and $g_S$ as well as the unpolarized, polarized and transversity parton distribution function (PDF) momentum fractions $\langle x\rangle_{u^+-d^+}$, $\langle x\rangle_{\Delta u^--\Delta d^-}$ and $\langle x\rangle_{\delta u^+-\delta ^+}$. The simulations are carried out on a subset of the (isospin symmetric) $N_f=2+1$ flavour Coordinated Lattice Simulations (CLS) gauge ensembles with lattice spacings ranging from $a\approx 0.086\,$fm down to $a\approx 0.050\,$fm. First results on the breaking of flavour symmetry and the low energy constants $F$ and $D$ are presented. While SU(3) flavour symmetry violations are found to be sizeable for $g_A=\langle 1\rangle_{\Delta u^+-\Delta d^+}$, these are quite small for $g_T=\langle 1\rangle_{\delta u^--\delta d^-}$ and $\langle x\rangle_{u^+-d^+}$.Comment: 7 pages, 5 figures, talk given at Lattice 2019, v2: corrected some typo