Neutrinos

Thorsten Lux

For more than a decade IFAE has been contributing to several key experiments in the field of neutrino physics, such as K2K, which obtained the first measurement of neutrino oscillations with a neutrino beam from an accelerator, and T2K, that presented in 2011 the first indication of the transformation of muon neutrinos into electron neutrinos, thereby demonstrating a non-zero value for the third mixing angle. Currently the focus of the group lays on the preparation of the T2K near detector upgrade and the evaluation of the liquid argon dual phase (LAr DP) concept as far detector for the Deep Underground Neutrino Experiment (DUNE).

T2K Scientific Results in 2019

T2K continued to take data in 2019 with a record beam power of 515 kW and overall accumulated statistics of about 3.6 x1021 protons-on-target (POT). The T2K search for light sterile neutrinos significantly improved the exclusion limits set by other experiments (Fig. 1).

Figure 1: Exclusion plot for the oscillation parameters for sterile parameters compared with results from other experiments.

T2K ND280 UPGRADE

The IFAE group is significantly involved in the upgrade project of the near detector (ND280) of T2K. The IFAE PI is technical project manager of this international project which collaborators from Japan, Russia, Italy, France, Switzerland, Poland and CERN. The group contributes to the design of the tracker detector and achieved that main parts of this detector are produced by a Spanish company. Fig. 2 shows the dE/dx capability of the detector as studied at a testbeam at CERN. The results of this study were published in 2019. Fig. 3 shows an event display of the tracker prototype which was produced by the Spanish company and the IFAE group provided also the DAQ system.

Figure 2: dE/dx distribution as measured at the testbeam using different particle types.

Figure 3: Event display from the TPC prototype produced in Spain.

ProtoDUNE-DP Commissioning

During summer 2019, the PI and 3 students stayed at CERN contributing to the final installation steps and commissioning of the ProtoDUNE-DP detector. The Spanish groups, IFAE together with CIEMAT, provided the photon detection system based on 36 PMTs (Fig. 4). The detector was successfully commissioned and the first track could be observed (Fig. 5).

Figure 4: Array of PMTs within ProtoDUNE-DP

Figure 5: Event display of the charge readout of ProtoDUNE-DP