Prediction of Energy Resolution in the JUNO Experiment
This paper presents an energy resolution study of the JUNO experiment,incorporating the latest knowledge acquired during the detector constructionphase. The determination of neutrino mass ordering in JUNO requires anexceptional energy resolution better than 3\% at 1~MeV. To achieve thisambitious goal, significant efforts have been undertaken in the design andproduction of the key components of the JUNO detector. Various factorsaffecting the detection of inverse beta decay signals have an impact on theenergy resolution, extending beyond the statistical fluctuations of thedetected number of photons, such as the properties of the liquid scintillator,performance of photomultiplier tubes, and the energy reconstruction algorithm.To account for these effects, a full JUNO simulation and reconstructionapproach is employed. This enables the modeling of all relevant effects and theevaluation of associated inputs to accurately estimate the energy resolution.The results of study reveal an energy resolution of 2.95\% at 1~MeV.Furthermore, this study assesses the contribution of major effects to theoverall energy resolution budget. This analysis serves as a reference forinterpreting future measurements of energy resolution during JUNO datacollection. Moreover, it provides a guideline for comprehending the energyresolution characteristics of liquid scintillator-based detectors.