Proposal: JSNS$^2$-II
Abstract
This article describes the goal and expected sensitivity of the JSNS-II experiment at J-PARC Materials and Life Science Experimental Facility (MLF). The JSNS-II experiment is the second phase of the JSNS experiment (J-PARC Sterile Neutrino Search at J-PARC Spallation Neutron Source) with two detectors which are located in 24 m (an existing detector) and 48 m (new one) baselines to improve the sensitivity of the search for sterile neutrinos, especially in the low region, which has been indicated by the global fit of the appearance mode. The new second detector has a similar structure as the existing JSNS detector, which is already working. To compensate for the reduction of the neutrino flux due to the distance from the mercury target, the target mass of the Gd-loaded liquid scintillator which is the Linear AlkylBenzene (LAB) based liquid scintillator inside the acrylic vessel is 35 tons. To keep the same photo-coverage of the detector as the first detector, we will surround the acrylic vessel with 240 PMTs. With this experimental setup and 5 years (times 1 MW beam power) exposure, the sensitivity of the JSNS-II is significantly improved compared to the current JSNS, especially in the low oscillation parameter region. The JSNS-II can also confirm or refute the most of the oscillation parameters' space preferred by the previous experiments with 3 sigma C.L.. Considering these situations and world wide status of the sterile neutrino searches, we are eager to start the data taking with the two detector configuration from 2023. The fund to build the second detector was already secured.
Cite
@article{arxiv.2012.10807,
title = {Proposal: JSNS$^2$-II},
author = {S. Ajimura and M. Botran and J. H. Choi and J. W. Choi and M. K. Cheoun and T. Dodo and H. Furuta and J. Goh and K. Haga and M. Harada and S. Hasegawa and Y. Hino and T. Hiraiwa and H. I. Jang and J. S. Jang and M. C. Jang and H. Jeon and S. Jeon and K. K. Joo and J. R. Jordan and D. EJung and S. K. Kang and Y. Kasugai and T. Kawasaki and E. J. Kim and J. Y. Kim and S. B. Kim and S. Y. Kim and W. Kim and T. Konno and H. Kinoshita and D. H. Lee and S. Lee and I. T. Lim and E. Marzec and T. Maruyama and S. Masuda and S. Meigo and S. Monjushiro and D. H. Moon and T. Nakano and M. Niiyama and K. Nishikawa and M. Nomachi and M. Y. Pac and J. S. Park and S. J. M. Peeters and H. Ray and G. Roellinghoff and C. Rott and K. Sakai and S. Sakamoto and T. Shima and C. D. Shin and J. Spitz and I. Stancu and Y. Sugaya and F. Suekane and K. Suzuya and M. Taira and R. Ujiie and Y. Yamaguchi and M. Yeh and I. S. Yeo and C. Yoo and I. Yu and A. Zohaib},
journal= {arXiv preprint arXiv:2012.10807},
year = {2020}
}