The Jiangmen Underground Neutrino Observatory(JUNO)features a 20 kt multi-purpose underground liquid scintillator sphere as its main detector.Some of JUNO's features make it an excellent location for^8B solar neut...The Jiangmen Underground Neutrino Observatory(JUNO)features a 20 kt multi-purpose underground liquid scintillator sphere as its main detector.Some of JUNO's features make it an excellent location for^8B solar neutrino measurements,such as its low-energy threshold,high energy resolution compared with water Cherenkov detectors,and much larger target mass compared with previous liquid scintillator detectors.In this paper,we present a comprehensive assessment of JUNO's potential for detecting^8B solar neutrinos via the neutrino-electron elastic scattering process.A reduced 2 MeV threshold for the recoil electron energy is found to be achievable,assuming that the intrinsic radioactive background^(238)U and^(232)Th in the liquid scintillator can be controlled to 10^(-17)g/g.With ten years of data acquisition,approximately 60,000 signal and 30,000 background events are expected.This large sample will enable an examination of the distortion of the recoil electron spectrum that is dominated by the neutrino flavor transformation in the dense solar matter,which will shed new light on the inconsistency between the measured electron spectra and the predictions of the standard three-flavor neutrino oscillation framework.IfDelta m^(2)_(21)=4.8times10^(-5);(7.5times10^(-5))eV^(2),JUNO can provide evidence of neutrino oscillation in the Earth at approximately the 3sigma(2sigma)level by measuring the non-zero signal rate variation with respect to the solar zenith angle.Moreover,JUNO can simultaneously measureDelta m^2_(21)using^8B solar neutrinos to a precision of 20% or better,depending on the central value,and to sub-percent precision using reactor antineutrinos.A comparison of these two measurements from the same detector will help understand the current mild inconsistency between the value of Delta m^2_(21)reported by solar neutrino experiments and the KamLAND experiment.展开更多
Horizontal strengthened storeys are widely used in super high-rise steel structures to improve the lateral structural rigidity.This use has great effects on the seismic properties of the entire structure.The seismic p...Horizontal strengthened storeys are widely used in super high-rise steel structures to improve the lateral structural rigidity.This use has great effects on the seismic properties of the entire structure.The seismic properties of the Wuhan International Securities Building (a 68-storey super high-rise steel structure with three horizontal strengthened storeys) were evaluated in this study.Two approaches,i.e.,mode-superposition response spectrum analysis and time-history analysis,were employed to calculate the seismic response of the structure.The response spectrum analysis indicated that transition parts near the three strengthened storeys were weak zones of the structure because of the abrupt change in rigidity.In the response spectrum analysis approach,the Square Root of Sum of Square (SRSS) method was recommended when the vertical seismic effects could be ignored.However,the complete quadratic combination (CQC) method was superior to SRSS method when the vertical seismic effects should be considered.With the aid of time-history analysis,the seismic responses of the structure were obtained.The whiplash effect that spectrum analysis cannot reveal was observed through time-history analysis.This study provides references for the seismic design of super high-rise steel structures with horizontal strengthened storeys.展开更多
基金This work was supported by the Chinese Academy of Sciences,the National Key R&D Program of China,the CAS Center for Excellence in Particle Physics,the Joint Large Scale Scientific Facility Funds of the NSFC and CAS,Wuyi University,and the Tsung-Dao Lee Instiute of Shanghai Jiao Tong University in China,the In stiut National de Physique Nucleaire et de Physique de Particules(IN2P3)in France,the Istituto Nazionale di Fisica Nucleare(INFN)in Italy,the Fond de la Recherche Scintifique(F.R.S-FNRS)and FWO under the"Excellence of Science-EOS"in Belgium,the Conselho Nacional de Desenvolvimento Cientificoce Tecnologico in Brazil,the Agencia Nacional de Investigacion y Desrrollo in Chile,the Charles University Research Centre and the Ministry of Education,Youth,and Sports in Czech Republic,the Deutsche Forschungsgemeinschaft(DFG),the Helmholtz Association,and the Cluster of Exellence PRISMA+in Germany,the Joint Institute of Nuclear Research(JINR),Lomonosov Moscow State University,and Russian Foundation for Basic Research(RFBR)in Russia,the MOST and MOE in Taiwan,the Chu-lalongkorm University and Suranaree University of Technology in Thailand,and the University of aliformia at Irvine in USA.
文摘The Jiangmen Underground Neutrino Observatory(JUNO)features a 20 kt multi-purpose underground liquid scintillator sphere as its main detector.Some of JUNO's features make it an excellent location for^8B solar neutrino measurements,such as its low-energy threshold,high energy resolution compared with water Cherenkov detectors,and much larger target mass compared with previous liquid scintillator detectors.In this paper,we present a comprehensive assessment of JUNO's potential for detecting^8B solar neutrinos via the neutrino-electron elastic scattering process.A reduced 2 MeV threshold for the recoil electron energy is found to be achievable,assuming that the intrinsic radioactive background^(238)U and^(232)Th in the liquid scintillator can be controlled to 10^(-17)g/g.With ten years of data acquisition,approximately 60,000 signal and 30,000 background events are expected.This large sample will enable an examination of the distortion of the recoil electron spectrum that is dominated by the neutrino flavor transformation in the dense solar matter,which will shed new light on the inconsistency between the measured electron spectra and the predictions of the standard three-flavor neutrino oscillation framework.IfDelta m^(2)_(21)=4.8times10^(-5);(7.5times10^(-5))eV^(2),JUNO can provide evidence of neutrino oscillation in the Earth at approximately the 3sigma(2sigma)level by measuring the non-zero signal rate variation with respect to the solar zenith angle.Moreover,JUNO can simultaneously measureDelta m^2_(21)using^8B solar neutrinos to a precision of 20% or better,depending on the central value,and to sub-percent precision using reactor antineutrinos.A comparison of these two measurements from the same detector will help understand the current mild inconsistency between the value of Delta m^2_(21)reported by solar neutrino experiments and the KamLAND experiment.
文摘Horizontal strengthened storeys are widely used in super high-rise steel structures to improve the lateral structural rigidity.This use has great effects on the seismic properties of the entire structure.The seismic properties of the Wuhan International Securities Building (a 68-storey super high-rise steel structure with three horizontal strengthened storeys) were evaluated in this study.Two approaches,i.e.,mode-superposition response spectrum analysis and time-history analysis,were employed to calculate the seismic response of the structure.The response spectrum analysis indicated that transition parts near the three strengthened storeys were weak zones of the structure because of the abrupt change in rigidity.In the response spectrum analysis approach,the Square Root of Sum of Square (SRSS) method was recommended when the vertical seismic effects could be ignored.However,the complete quadratic combination (CQC) method was superior to SRSS method when the vertical seismic effects should be considered.With the aid of time-history analysis,the seismic responses of the structure were obtained.The whiplash effect that spectrum analysis cannot reveal was observed through time-history analysis.This study provides references for the seismic design of super high-rise steel structures with horizontal strengthened storeys.
