暗物质与中微子-粒子物理的两朵乌云.ppt

/2015/reviews/rpp2015-rev-light-neutrino-types.pdf”/2015/reviews/rpp2015-rev-light-neutrino-types.pdfHowsmallNeutrinoMass?CosmologicalMassLimit:WMAP01Theevidenceoftheoscillations ofneutrinos02A.Solarneutrinos03B.Atmosphericneutrinos04C.NuclearreactorneutrinosHowtheSunburnsSolarneutrinosSolarneutrinodeficitisnowunderstoodasaconsequenceofneutrinososcillation.Atmosphere2Atmosphericneutrinos1(Signoftheparticlesareneglectedinthisfigure.)Ahalfof??lost!!NuclearreactorneutrinosReactorLongBaselineExperiment150-210km(Epr2.6MeV)DayaBayExperiment:LayoutRelativemeasurementtocancelCorrelatedSystematicErrors2nearsites,1farsiteMultipleAntineutrinoDetectormodulesateachsitetoreduceUncorrelatedSyst.ErrorsFar:4modules，near:2modulesMultiplemuondetectorstoreducevetoefficiencyuncertaintiesWaterCherenkov：2layersRPC：4layersatthetop+telescopesRedundancy!!!Crosscheck;Reduceerrorsby1/?Nc2AnalysisNoconstrainonabsolutenormalization.Fitonthenear-farrelativemeasurement.c2/NDF=4.26/45.2σfornon-zeroθ13Sin22q13=0.092?0.016(stat)?0.005(syst)01Electronanti-neutrinodisappearanceisobservedatDayaBay,togetherwithaspectraldistortionAnewtypeofneutrinooscillationisthusdiscoveredR=0.940±0.011(stat)±0.004(syst),02ResultsofDayaBayExperimentA.Neutrinooscillationinvacuum1B.Neutrinooscillationinmatter2TheoryofneutrinooscillationNeutrinoscomefromatleastthreeflavorsTheknownthreeflavors:Eachoftheseisassociatedwiththecorrespondingcharged-leptonflavor:ThemeaningofthisassociationOvershortdistance,neutrinosdonotchangeflavor:DoesnotoccurButifneutrinoshavemasses,andleptonsmix,neutrinoflavorchangesdooccurduring longjourneysLetusassumeneutrinohavemassandleptonsmixWhenW+decays:Theproducedneutrino