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arXiv · 2405.20875

Progress on nucleon transition matrix elements with a lattice QCD variational analysis

Lorenzo Barca·Gunnar Bali·Sara Collins
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Abstract

Nucleon weak matrix elements can be extracted from nucleon correlation functions with lattice QCD simulations. The signal-to-noise ratio prohibits the analysis at large source-sink separations and as a consequence, excited state contamination affects the extraction of the nucleon matrix elements. Chiral perturbation theory (ChPT) suggests that the dominant contamination in some of these channels is due to $Nπ$ states where the pion carries the same momentum of the current. In this talk, we report updates on the variational analysis with $qqq$-operators (nucleon-like) and $(qqq)(\bar{q}q)$-operators (nucleon-pion-like) where we report for the first time some preliminary results of $\langle Nπ| \mathcal{J}| N \rangle $, modulo some kinematic and volume factors, and we compare the results against ChPT. This pilot study is performed on a CLS ensemble with $N_f=3$, $m_π\approx 420~\mathrm{MeV}$, $a\approx 0.1~\mathrm{fm}$ and $T=2L\approx 4.8~\mathrm{fm}$.

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Lorenzo Barca, Gunnar Bali, Sara Collins. 2024-05-31. Progress on nucleon transition matrix elements with a lattice QCD variational analysis. https://arxiv.org/abs/2405.20875

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