EMMI Workshop: Long-Baseline Neutrino Reference Measurements with Hadron Beams at GSI/FAIR

Towards precision LBL neutrino energy and flux measurements exploiting pion–nucleus and proton–nucleus reference measurements with HADES and CBM

Precision long-baseline (LBL) neutrino experiments require improved modelling of neutrino-nucleus interactions. The description of the interaction between ejected hadrons and the residual nucleus (called final-state interactions, FSI) are important for accurate neutrino energy reconstruction but are particularly challenging to model. Fortunately, FSI models in neutrino interaction event generators can be constrained by dedicated pion-nucleus and proton-nucleus reference measurements.

With the secondary pion beam and HADES at SIS18, and future proton-nucleus scattering capabilities with CBM at FAIR, GSI/FAIR can provide essential hadron-nucleus scattering data in kinematic regimes relevant for LBL experiments. 

This workshop aims to develop a prioritized roadmap for GSI/FAIR measurements to support LBL experiments. It will connect the communities from GSI/FAIR, hadron-beam measurements, LBL neutrino experiments, neutrino interaction event generators and FSI modelling.

Key topics

·         LBL neutrino-interaction and FSI systematics

·         Pion and nucleon propagation in nuclei: absorption, charge exchange, rescattering

·         External π+A and p+A constraints for neutrino generators

·         Feasibility of π+A measurements with the GSI pion beam and HADES

·         Complementary p+A opportunities with CBM at FAIR

·         Prioritized targets, momenta, observables and required precision

·         Generator-ready data products: unfolded spectra, covariances, tuning interfaces

·         Roadmap for full, bridge and staged measurement scenarios