An Event Reconstruction Algorithm In The Central Detector Of JUNO

The Jiangmen Underground Neutrino Observatory(JUNO),a multi-purpose underground liquid scintillator detector,was proposed with the determination of the neutrino mass hierarchy(MH)by reactor anti-neutrino as a primary physics goal.The measurement of antineutrino spectrum with excellent energy resolution will also lead to the precise determination of the neutrino oscillation parameters sin2 θ12,△m21 2,and | △mee2 | to an accuracy of better than 1%,which will paly a crucial role in the future test of the MNSP matrix.The JUNO detector is capable of observing not only antineutrino from the power plants,but also neutri-no/antineutrino from terrestrial and extra-terrestrial sources,including supernova burst neutrinos,diffuse supernova neutrino background,geoneutrinos,atmospher-ic neutrinos and solar neutrinos.JUNO is also sensitive to several beyond the standard-model physics.Examples include the search for sterile neutrinos of dif-ferent energy scales,search for proton decay via the p→ K++v decay channel,search for neutrinos resulting from dark-matter annihilation in the Sun,search for violation of Lorentz invariance via the sidereal modulation of the reactor neutrino event rate,and search for the effects of non-standard interactions.The proposed construction of the JUNO detector will provide a unique facility to address many outstanding crucial questions in particle and astrophysics in a timely and cost-effective fashion.It holds the great potential for future advancing our quest to understanding the fundamental properties of neutrinos,one of the building blocks of our Universe.The JUNO detector is defined as central detector(CD),liquid scintillator(LS),PMT system,VETO detector and calibration system.The central detector will build a super acrylic sphere and a stainless-steel truss,which will hold 20-kton liquid scintillator,18000 20-inch PMTs and 25000 3-inch PMTs.The VETO detector will be divided into a top tracker and a water Cherenkov detector.The calibration system will provide different methods for JUNO calibration.The expected energy resolution is going to reach 3%(?)(MeV).To meet the requirements of the experiment’ an algorithm of vertex and energy reconstruction which takes advantage of time and charge information of PMTs has been devel-oped by deploying maximum likelihood method.The key point to the success of the reconstruction algorithm is a good understanding of the complicated optical process in the liquid scintillator.