A new generation of long-baseline (LBL) neutrino oscillation experiments is under construction to explore fundamental neutrino properties. Their sensitivity reach depends critically on knowledge of neutrino-nucleus cross sections [1], not yet established at the required percent level precision. An important reaction channel is charged-current quasi-elastic neutrino scattering (CCQE) which is closely related to muon capture on the proton.

nu + n ⇔ mu + p

Recent work showed that the theoretical predictions for this processes are subject to significant uncertainties due to the axial form factor, specifically the axial radius entering its Q^{2} momentum expansion [2]. This dominates the theory uncertainty for muon capture and doubles the uncertainty for CCQE predictions in the kinematic range of LBL experiments [3]. In addition, it complicates the validation of theoretical models against existing nu+A scattering data.

This workshop explores synergies between neutrino and muon communities to address some of these questions, e.g.

- Impact of neutrino cross sections for oscillation experiments
- Theory status and prospects towards ab-inito calculations
- Axial radius determination via a high precision µ+p capture experiment
- Can theory calculate this process at per-mille precision?
- Is a new high precision experiment at the required 0.3% level feasible?

- Complementary approaches to measure elemental neutrino cross sections and to determine the axial form factor
- Advanced technologies and beams for a high precision µ+p experiment

[1] Prog. Part. Nucl. Phys. 100 (2018) 1–68

[2] Phys.Rev. D 93, 113015 (2016)

[3] Rep. Prog. Phys. 81 (2018) 096301