Eur. Phys. J. C (2021) 81: 1130
https://doi.org/10.1140/epjc/s10052-021-09845-8

Regular Article - Theoretical Physics

Updated physics performance of the ESSnuSB experiment

ESSnuSB collaboration

¹ CERN, 1211, Geneva 23, Switzerland
² Uppsala University, P.O. Box 256, 751 05, Uppsala, Sweden
³ IPHC, Université de Strasbourg, CNRS/IN2P3, Strasbourg, France
⁴ European Spallation Source, Box 176, 221 00, Lund, Sweden
⁵ Department of Physics, School of Engineering Sciences, KTH Royal Institute of Technology, Roslagstullsbacken 21, 106 91, Stockholm, Sweden
⁶ The Oskar Klein Centre, AlbaNova University Center, Roslagstullsbacken 21, 106 91, Stockholm, Sweden
⁷ Faculty of Physics, Sofia University St. Kliment Ohridski, 1164, Sofia, Bulgaria
⁸ Department of Physics, Lund University, P.O Box 118, 221 00, Lund, Sweden
⁹ Department of Physics and Astronomy, FREIA, Uppsala University, Box 516, 751 20, Uppsala, Sweden
¹⁰ Faculty of Engineering, Lund University, P.O Box 118, 221 00, Lund, Sweden
¹¹ University of Milano-Bicocca and INFN sez. di Milano-Bicocca, Milan, Italy
¹² Institute of Nuclear and Particle Physics, NCSR Demokritos, Neapoleos 27, 15341, Agia Paraskevi, Greece
¹³ Departamento de Fisica Teorica and Instituto de Fisica Teorica, IFT-UAM/CSIC, Universidad Autonoma de Madrid, Cantoblanco, 28049, Madrid, Spain
¹⁴ Center of Excellence for Advanced Materials and Sensing Devices, Ruder Bošković Institute, 10000, Zagreb, Croatia
¹⁵ School of Physics, University of Hyderabad, 500046, Hyderabad, India
¹⁶ Department of Physics, Faculty of Science and Letters, University of Cukurova, 01330, Adana, Turkey
¹⁷ Department of Physics, University of Rijeka, 51000, Rijeka, Croatia
¹⁸ INFN sez. di Padova, Padua, Italy
¹⁹ Institute for Experimental Physics, Hamburg University, 22761, Hamburg, Germany
²⁰ Spallation Neutron Science Center, 523803, Dongguan, China
²¹ resent address: The center for Exotic Nuclear Studies, Institute for Basic Science, 34126, Daejeon, Korea

^p loris.dalessi@iphc.cnrs.fr
^aa mghosh@irb.hr
^ae budimir.klicek@irb.hr

Received: 29 July 2021
Accepted: 17 November 2021
Published online: 23 December 2021

Abstract

In this paper, we present the physics performance of the ESSnuSB experiment in the standard three flavor scenario using the updated neutrino flux calculated specifically for the ESSnuSB configuration and updated migration matrices for the far detector. Taking conservative systematic uncertainties corresponding to a normalization error of $5\%$ for signal and $10\%$ for background, we find that there is $10\sigma$$(13\sigma )$ CP violation discovery sensitivity for the baseline option of 540 km (360 km) at ${\delta }_{\mathrm{CP}}=\pm {90}^{\circ }$. The corresponding fraction of ${\delta }_{\mathrm{CP}}$ for which CP violation can be discovered at more than $5\sigma$ is $70\%$. Regarding CP precision measurements, the $1\sigma$ error associated with ${\delta }_{\mathrm{CP}}=0^{\circ }$ is around $5^{\circ }$ and with ${\delta }_{\mathrm{CP}}=-{90}^{\circ }$ is around ${14}^{\circ }$$(7^{\circ })$ for the baseline option of 540 km (360 km). For hierarchy sensitivity, one can have $3\sigma$ sensitivity for 540 km baseline except ${\delta }_{\mathrm{CP}}=\pm {90}^{\circ }$ and $5\sigma$ sensitivity for 360 km baseline for all values of ${\delta }_{\mathrm{CP}}$. The octant of ${\theta }_{23}$ can be determined at $3\sigma$ for the values of: ${\theta }_{23}>{51}^{\circ }$ (${\theta }_{23}<{42}^{\circ }$ and ${\theta }_{23}>{49}^{\circ }$) for baseline of 540 km (360 km). Regarding measurement precision of the atmospheric mixing parameters, the allowed values at $3\sigma$ are: ${40}^{\circ }<{\theta }_{23}<{52}^{\circ }$ (${42}^{\circ }<{\theta }_{23}<51.5^{\circ }$) and $2.485\times {10}^{-3}$ eV${}^2<\Delta m_{31}^2<2.545\times {10}^{-3}$ eV${}^2$ ($2.49\times {10}^{-3}$ eV${}^2<\Delta m_{31}^2<2.54\times {10}^{-3}$ eV${}^2$) for the baseline of 540 km (360 km).