Speaker
Description
The FASER experiment studies three generations of neutrinos in the unexplored TeV region using the Large Hadron Collider at center-of-mass energy of 13.6 TeV.
The FASER detector is located 480 m downstream of the ATLAS IP and the FASER$\nu$ emulsion detector consists of 730 layers of emulsion films and tungsten plates with a thickness of 1.09 mm.
Thanks to the high spatial resolution of the emulsion detector, neutrino interaction vertices can be precisely identified, enabling measurements of neutrino cross sections as a function of energy.
To achieve this, the momentum measurement of charged particles from 100 GeV to a few TeV is essential. The momentum is measured from the position deviations due to multiple Coulomb scattering.
To validate the developed method, a test beam was performed at CERN’s SPS in the summer of 2024. A 100-layer detector was irradiated with muon beams of 100, 200, and 300 GeV. The reconstructed momentum distributions agree well with the MC simulations, and the momentum resolution is estimated to be 20-23%.
In 2024, we performed the first measurement of $\nu_{e}$ and $\nu_{\mu}$ interaction cross sections in the TeV energy region using a subset of the 9.5 fb-1 dataset with the FASER$\nu$ detector.
Using the full 9.5fb-1 dataset, differential cross section measurements as a function of neutrino energy were performed. The neutrino energy was reconstructed using a TMVA-based multivariate analysis method, which incorporates the reconstructed lepton momentum and the sum of hadronic momenta as input variables. The reconstructed energy distribution was then unfolded to the true neutrino energy. In this poster, we present the validation of the momentum reconstruction method using test beam data, as well as the latest results on neutrino cross-section measurements as a function of energy.