The 4th Workshop on New Physics Opportunities at Neutrino Facilities

Searching for ντ disappearance in the SHiP experiment

4 Jun 2024, 16:20

20m

Science and Culture Center (IBS)

Contributed talks I

Speaker

Seong Moon Yoo (Sung Kyun Kwan University)

Description

We study the expected sensitivity to the mixing between sterile and tau neutrinos directly from the tau neutrino disappearance in the high-energy fixed target experiment. Here, the beam energy is large enough to produce tau neutrinos at the target with large luminosity. During their propagation to the detector, the tau neutrino may oscillate into sterile neutrino. By examining the energy spectrum of the observed tau neutrino events, we can probe the mixing between sterile and tau neutrinos directly. In this paper, we consider Scattering and Neutrino Detector (SND) at SHiP experiment as a showcase, which uses 400 GeV protons from SPS at CERN, and expect to observe 6,300 tau and anti-tau neutrinos from the $2\times {10}^{20}$ POT for 5 years operation. Assuming the uncertainty of 10\%, we find the sensitivity $|U_{\tau 4}{|}^2\sim 0.08$\, (90\% CL) for $\mathrm{\Delta }{m}_{41}^2\sim 500{\mathrm{eV}}^2$ with 10\% signal-to-background ratio. We also consider a far SND at the end of the SHiP Hidden Sector Decay Spectrometer (HSDS), in which case the sensitivity would be enhanced to $|U_{\tau 4}{|}^2\sim 0.02$. Away from this mass, the sensitivity becomes lower than $|U_{\tau 4}{|}^2\sim 0.15$ for $\mathrm{\Delta }{m}_{41}^2\lesssim 100{\mathrm{eV}}^2$ or $\mathrm{\Delta }{m}_{41}^2\gtrsim {10}^4{\mathrm{eV}}^2$.

Presentation materials

NPN_2024_SMY.pdf