大亚湾反应堆中微子实验-王贻芳

　36(2007)3　　　　　　　　　　　　　http:／／*王　贻　芳†(　　100049)　　　,,、.6,:θ13CPδ.,sin22θ1390%0.01,.,“”.　　,,,,AneutrinoexpermientusingtheDayaBayreactorWANG　Yi-Fang†(InstituteofHighEnergyPhysics,ChineseAcademyofSciences,Beijing100049,China)Abstract　　Neutrinooscillationistheonlyphenomenoncurrentlyknownbeyondthestandardmodelofparticlephysics.Itprovesthattheneutrinomassisnotnull,aconclusionextremelyimportanttoparticlephysics,astro-physicsandcosmology.Amongthesixparametersfordescribingneutrinooscillations,twoarestillunknown:themixingangleθ13andtheCPphaseδ.WeproposetobuildanexperimentneartheDayaBaynuclearpowerstationtomeasurethemixinganglesin22θ13toaprecisionof0.01at90%confidencelevel,animprovementofaboutoneorderofmagnitudeoverpastexperiments.Thiswillprovideaguidelineforthefuturedevelopmentofneutrinophysics,andinparticularfortheunderstandingoftheabsenceofanti-matterintheuniverse.Keywords　　neutrino,detector,oscillation,mixing,anti-matter*　(:2006CB808100)、(:10225524,10535050,10475086)2006-11-15,2007-01-04†　Email:[e-mail]　　[1],,,,6,———θ13.sin22θ1390%0.01,,,“”.,、、、、、,,.1　实验的科学意义与目标1.1　θ13,123(,μ207http:／／　　　　　　　　　　　　　　　　　　　　τ).,,.,100/cm3,..,,,,.,[2].60,PontecorvoB,,,,,.,.:νeνμντ=1　0　00c23s230-s23c23c130s130e-iδ0-s130c13c12s120-s12c1200　0　1ν1ν2ν3,cij=cosθij,sij=sinθij(i,j=1,2,3).(θ23),(θ12).Homestate,Super-K,SNOKamLAND,[3].、,HomestateSuper-KDavisR2002.θ13CPδ,2004sin22θ13[4],θ13:(1)6,,.(2)θ13CPδ,CPlep-togenesis“”,.sin22θ130.01—0.03,CP,“”.,CP,.(3)sin22θ13.sin22θ13,.(4),,.sin22θ13,,0.001—0.1[5],1.sin22θ130.01.sin22θ13(),,,.1　sin22θ13.sin22θ13.Chooz,PaloVerdeSuper-Ksin22θ13,2[6].sin22θ1390%0.17,3.9%.sin2θ130.01[7](sin22θ13=0.04).sin22θ130.01,0.5%,.1.2　θ13,208　36(2007)3　　　　　　　　　　　　　http:／／　sin22θ13　(a)[6],sin22θ13;(b),sin2θ130.01[7].,.,,,,.();,();,θ13.,θ13,:P(νμ→νe)≈sin2θ23sin2θ13sin2(1.27Δm223L/E)+cos2θ23sin22θ12sin2(1.27Δm212L/E)-A(ρ)cos2θ13sinθ13sinδ,θ13、A(r)CPδCP.P(νμ→νe).,μ,.,,,(),.,,.,,θ13.:P(ν_e→ν_e)≈1-sin22θ13sin2(1.27Δm213L/E)-cos4θ13sin22θ12sin2(1.27Δm212L/E).θ13,θ13.,,.3,2km.,.,θ13.,,.(Δm232δCP).3　,.θ13,θ121.3　,θ13.2003,,209http:／／　　　　　　　　　　　　　　　　　　　　1　()/GW(/)/m(/)/t(/)MWEsin22θ13/(90%C.L.)()17.4400/180040/80300/10000.008DoubleChooz()8.4150/105010/1060/3000.03RENO()17.3150/150020/20230/6750.03AngradosReis()4.1300/130050/500200/17000.007Braidwood()6.5270/1800130/130450/4500.01KASKA()24.3350/160012/12300/3000.02DiabloCanyon()6.4400/180025/50600/6000.01Krasnoyarsk()3.2115/100046/46100/7000.014　θ13.,、、,8..(2010),,,,4.、、,..1.,.,DiabloCanyonBraidwood,DoubleChoozKASKA,DoubleChooz.2　反应堆中微子探测及其实验.β,ν-e+p→e++ne+;(30μs),8MeVγ,..,,,.γ(3MeV),.2.2MeV,.β,,.5,β.2080,,,6[8].20200,.Chooz,2.7%,2.8%[9].3　大亚湾中微子实验3.1　,,(3—6)%,(2—3)%,(1—3)%,(1—3)%.90%0.01,0.5%.,210　36(2007)3　　　　　　　　　　　　　http:／／　,β6　[8](),(),,、、.,,7.(364m)(504m),1615m,1985m.,、、.,,,,.,.,,3000m.7　,21,3.2　:,.,.8.3.2.1　中微子探测器,,.,,,.,,,.,,.,,,.211http:／／　　　　　　　　　　　　　　　　　　　　8　():4,2.5m.(RPC).,20,80,0.2%.,,,5m,5m,100,9.20.,20,,,.40,,2248,..,、,、、.,.3.2.2　muon子探测器,.,99.5%,0.25%.,.,9　(,,,,)10　,sin22θ13=0.01,.SuperKKamLANDGeant4,95%,.,,95%.,99.5%,0.25%.,.212　36(2007)3　　　　　　　　　　　　　http:／／　,.,,.:.,,μ.:(1),,;(2)μ,,;(3)μ,8He9Li.15%50%()β,.,,μ,.、,,、.μGEANT3,,2.10.,,100%,/.2　/(m)3645041985/1618(m)98112355(//)93076090(Hz/m2)1.160.730.041(GeV)5560138/0.2%0.2%0.1%/0.1%0.1%0.1%8He+9Li/0.3%0.2%0.2%3.4　,:0.2%;0.1%;0.2%;/0.4%;/0.2%.,,pullχ2,A,ibin,MiAAi,T,F,N,S、.α,β,ε,η,σ,.,sin22θ1390%11.Δm2(),sin22θ130.01,.,.4　实验的组织,经费与计划15,13,,130.,,,,.,,..213http:／／　　　　　　　　　　　　　　　　　　　　11　,.1Chooz,290%.Δm2,.,,,,,1.7.,,.,,2009,2010.　　,,,,,.[1]WangY-F,hep-ex/0610024,talkgivenat33rdInternation-alCon.fonHighEnergyPhysics(ICHEP06),Moscow,Rus-sia,July26—Aug2,2006.DayaBayCol.l,hep-ex/0701029;[2]YaoW-Metal.J.Phys.,2006,G33:1[3]WangYF.In.tJ.Mod.Phys.A,2005,20:5244;Plenarytalkgivenat32ndInternationalConferenceonHigh-EnergyPhysics(ICHEP04).Beijing:China,16—22Aug2004[4][5]AndersonKetal.hep-ex/0402041[6]BoehmFetal.Phys.Rev.D,2000,62:072002[7]FogliGLetal.hep-ph/0506307[8]EguchiKetal.Phys.Rev.Let.t,2003,90:021802;2005,94:08180[9]ApollonioMetal.Eur.Phys.J.C,2003,27:331200510-21(),200610-18(aN).,,10-12(pN).,6pN,DNA9—20pN,DNA65pN.,SandiaS.Koch.Sandia.1,,,,.Sandia,K～1pN/nm.,,.,2nm,.Koch,,,、DNA,MEMS(),().Sandia,DNA.(云中客摘自AppliedPhysicsLetters,23October2006)214