粒子物理规划及 未来的中微子实验 王贻芳 南昌，2010 高能物理年会

Particle physics: problems and methods Standard Model: Higgs Beyond Standard Model ? SUSY, Extra-dimensions. Compositeness, … Details of SM (EW & QCD) : precision test, Confinement, Glueballs ? spectroscopy of particles… Neutrino properties: mass, oscillation, magnetic moment ? Majorana ? Cosmology related problems: antimatter(CP) ? Dark matter ? Relic-neutrinos, Monopoles ? Axions ? … High energy accelerators High intensity accelerators Underground experiments Surface experiments Space experiments

Experiments in the world and at home High energy accelerators High intensity accelerators Underground experiments Surface experiments Space experiments Tevetran: D0 CDF LHC ATLAS CMS ILC Flavor phys.: BELLE(II) - b DAFNE – s LHCb PANDA… High den. phys: ALICE J-PARC… n osc..: T2K Minos Project-X n osc. : SuperK KamLAND… bb decay: EXO Cuore Gerda… Dark matter: Xmass Xenon COUPP… Astronomy Monopole Proton decay… Cosmic-rays HESS MAGIC AUGER CTA mass Katrin n mag. Mom. TEXONO Grav. Wave Relic n Axions, … Anti-matter/ dark matter: PAMELA FERMI AMS… ATIC Asrtophysics: Integral Hubble WMAP Planck… Participate: ATLAS, CMS Flavor phys.: BESIII - c n osc. : Daya Bay Cosmic-rays Yang-Ba-Jin Asrtophysics: HXMT

高能物理未来发展的基本思路 High energy accelerators High intensity accelerators 积极参加国际合作 High intensity accelerators 充分利用BESIII，取得国际一流的成果 寻机建造下一代加速器 Underground experiments 充分利用大亚湾，取得国际一流的成果 准备建造下一代中微子实验 寻机建造新的实验：暗物质、bb decay、质子衰变、。。。 Surface experiments 充分利用ASg & ARGO，取得国际一流的成果 积极准备建设LHAASO Space experiments 尽快完成HXMT，取得国际一流的成果 寻机建造新的实验：宇宙线、天体物理、暗物质、。。。

时间安排 十二五 十三五 ：重要的建设项目 下一代中微子实验：大亚湾二期 十四五：重大建设项目 前期建设的丰收期  取得重大国际影响的成果 前期建设的丰收期  取得重大国际影响的成果 基础能力建设  达到国际先进水平 未来项目的准备与预研  具有国际竞争力 十三五 ：重要的建设项目 下一代中微子实验：大亚湾二期 地下实验：暗物质、bb decay、质子衰变、。。。 空间实验：宇宙线、天体物理、暗物质、。。。 十四五：重大建设项目 下一代加速器 每个新项目必须回答以下问题： 1）为什么（与其它可能的项目比较：科学目标、经费。。。） 2）怎么做（概念设计、国际竞争力、科学意义、经费、技术、进度、风 险。。。） 3）R&D（问题、技术、方案、计划。。。）

Neutrino oscillations: What we know and what we don’t know A mixing matrix: CP phase & q13 Majorana phase Atmospheric Solar Unknowns in neutrino oscillation: q13 , mass hierarchy, CP phase d + Majorana phase

n1 n2 n3 下一代中微子实验：大亚湾二期 mi ? 中微子振荡：中微子研究的中心 中微子振荡三个未解决的问题： q12太阳中微子振荡 质量顺序问题 大亚湾中微子实验二期 CP对称破缺角  未来的加速器实验 n1 n2 n3 q12太阳中微子振荡 q23大气中微子振荡 q13 ? mi ? 为什么反应堆中微子： 1）加速器中微子实验：造价昂贵 （探测器+加速器） 2）双β实验：造价昂贵，技术困难，风险巨大 3）中微子绝对质量测量：造价昂贵，技术困难 4）反应堆中微子实验：意义重大、风险小、条件优越、造价低、技术可行 测量磁矩：可能的未来，科学风险大 精确测量混合参数：大亚湾、大亚湾二期

Best neutrino source: reactor A powerful man-made source If not too far, more powerful than solar, atmospheric, and accelerator neutrinos A well understood source（~2%  ~ 0.1%） Better than solar(~5-10%), atmospheric(~10%), and accelerator(~5-10%  2-3% ??) neutrinos Adjustable baseline Of course, accelerator can do it also A free neutrino factory

Neutrino Mass hierarchy Fundamental to the Standard Model Fundamental to models beyond SM Most GUTs predict a normal mass hierarchy  a discriminator of different GUTs and/or neutrino mass models Fundamental to many issues: Matter-antimatter asymmetry via leptogenesis in specific seesaw models: hierarchy related Supernova neutrinos: collective flavor transitions due to inverted mass hierarchy Radiative corrections to mn and qij are more sensitive to the inverted hierarchy But even more important…

Dirac or Majorana ? Neutrino oscillation: beyond SM in a way of Dirac or Majorana mode ? bb exp. may never give positive results If mass hierarchy is known, together with next generation bb exp., the neutrino Dirac or Majorana nature can be determined. next gen. bb exp.

Measuring mass hierarchy Long baseline accelerator neutrinos Through Matter effects Expensive, project-X/LBNE in Fermilab/BNL Atmospheric neutrinos Very weak signal Huge detector, Expensive Reactor neutrinos Method: distortion of energy spectrum Enhance signature: Transform reactor neutrino L/E spectrum to frequency regime using Fourier formalism need Sin2(2q13) > 0.02 Need to know DM223 S.T. Petcov et al., PLB533(2002)94 S.Choubey et al., PRD68(2003)113006 J. Learned, PRD 78(2008)071302

Fourier transformation of L/E spectrum Frequency regime is in fact the DM2 regime  enhance the visible features in DM2 regime Take DM2 32 as reference NH: DM2 31 > DM2 32 , DM2 31 peak at the right of DM2 32 IH: DM2 31 < DM2 32 , DM2 31 peak at the left of DM2 32 L/E spectrum 12

Our efforts Clear distinctive features: Better than power spectrum FCT: NH: peak before valley IH: valley before peak FST: NH: prominent peak IH: prominent valley Better than power spectrum No pre-condition of Dm223 L. Zhan et al., PRD78:111103,2008 13

Quantify Features of FCT and FST To quantify the symmetry breaking, we define: RV/LV: amplitude of the right/left valley in FCT P/V: amplitude of the peak/valley in FST For asymmetric Pee NH: RL>0 and PV>0 IH: RL<0 and PV<0 Baseline: 46-72 km Sin2(2q13): 0.005-0.05 Others from global fit Two clusters of RL and PV values show the sensitivity of mass hierarchy determination L. Zhan et al., PRD78:111103,2008 2008-07-17 14

In reality Unfortunately, DM221 / DM223 ~ 3% L. Zhan, et. al., Phys.Rev.D79:073007,2009

Requirement To determine mass hierarchy at > 90% CL: Baseline: ~ 58 km, determined by q12 Reactor power > 24 GWth Flux and detector size: ~ (250-700) ktyear Ideally, sin22q13 > 0.02 & energy resolution < 2% IF sin22q13=0.01, energy resolution < 2% & 700 ktyear For sin22q13=0.02 , energy resolution < 3% & 700 ktyear Overburden > 1000 MWE ~ 60 km from Daya Bay A huge ne detector with mass >20kt currently the largest on is 1kt (KamLAND & LVD) 

Scientific goal: a l0-50kt underground LS detector 60km from reactor Neutrino Mass hierarchy Precision mixing para. measurement: q12, D M212, DM231  Unitarity of the mixing matrix Supernova neutrinos ==〉better than SuperK Geo-neutrinos ==〉10 better than KamLAND Atmospheric neutrinos ==〉 SuperK Solar neutrinos ? High energy neutrinos Point source: GRB, AGN, BH, … Diffused neutrinos High energy cosmic-muons Dark matter Exotics Sterile neutrinos Monopoles, Fractional charged particles, …. LVD+MACRO+KamLAND+ SuperK

Precision measurement of mixing parameter Fundamental to the Standard Model and beyond Similarities point to a Grand unification of leptons and quarks Constrain all PMNS matrix elements to < 1% ! Probing Unitarity of UPMNS to <1% level ! Current BESIII Vub 25% 5% Vcd 7% 1% Vcs 16% Vcb 3% Vtd 36% Vts 39% Current Daya Bay II Dm212 5% < 1% Dm223 12% sin2q12 10% Sin2q23 20% - sin2q13  If we can spend (0.1-0.5)B$ for each B/C/superB factories to understand UCKM (~ 1-2 elements for each factory), why not a super-reactor neutrino experiment(~ 3 elements) to understand UPMNS ?

Supernova neutrinos Less than 20 events observed so far (2001 Noble prize) Assumptions: Distance: 10 kpc (our Galaxy center) Energy: 31053 erg Ln the same for all types Tem. & energy Many types of events: ne + p  n + e+, ~ 3000 correlated events ne + 12C  13B* + e+, ~ 10-100 correlated events ne + 12C  11N* + e-, ~ 10-100 correlated events nx + 12C nｘ+ 12C*, ~ 600 correlated events nx + p  nｘ+ p, single events ne + e-  ne + e-, single events nx + e- nｘ+ e-, single events T(ne) = 3.5 MeV, <E(ne)> = 11 MeV T(ne) = 5 MeV, <E(ne)> = 16 MeV T(nx) = 8 MeV, <E(nx)> = 25 MeV SuperK can not see these correlated events

What to do with Supernova neutrinos Energy spectra & fluxes of all types of neutrinos tem. and average energy of neutrinos Understand Supernovae neutrino properties: mass, mixing, … Earth tomography Neutrino models … Arrival time of all types of neutrinos  absolute neutrino mass

Geo-neutrinos 238U, 232Th and 40K decays account for 40% of earth’s power, which is related to earthquakes, volcanoes, geomagnetism, plate tectonics, … They are mainly from mantle and crust, but not the core South-china and Japan are different Geo-neutrinos can tell 238U: 232Th  good for geo-models Only way looking inside the earth ? Already seen by KamLAND

Geo-neutrinos at Daya Bay II A factor of >10 larger than KamLAND 3 years KamLAND

探测器的概念设计 Neutrino target: ~20kt LS, LAB based 30m(D)30m(H) Oil buffer: 6kt Water buffer: 10kt PMT: 15000 20” Cost: ~1.5 B RMB

可能的地点：惠州或海上 据大亚湾/海丰60公里 热功率 > 40 GW

Technical challenges Requirements: Ongoing R&D: Large detector: >10 kt LS Energy resolution: 2%/E  2500 p.e./MeV Ongoing R&D: Low cost, high QE “PMT” A new design exist, patent pending, R&D contract to be signed with manufacture transparent LS: 15m  >25m Find out traces which absorb light, remove it from production Now: 1kt 250 p.e./MeV R&D program: ~ 3 years Useful for many future projects Support already from IHEP

基于LAB的液体闪烁体研究 测量LAB成分：~4.5% 杂质 利用量子化学的计算，估计、寻找吸收可见光的杂质 初步测量杂质在LAB中的比分 南京大学 高能所 测量LAB成分：~4.5% 杂质 利用量子化学的计算，估计、寻找吸收可见光的杂质 初步测量杂质在LAB中的比分 测量LAB样品中的碳、氧、氮、硫等元素及其相关杂质基团的空间精细结构；运用计算凝聚态物理和计算量子化学的相关原理与方法，深入解析、研究这些特殊杂质结构组分的光学性能及其空间组态效应。 研究去除这些杂质的方法 Linear- Alkyl- Benzene (C6H5 -R)

新型光电倍增管的设计:提高光量子效率 QE: Top: 20% Bottom: 80%*(20-40)% Total: (36-52)% Collection eff.: 60% (22-31)% 普通 PMT: 20%*0.6=12% 1）采用透射式光电阴极与反射式光电阴极相结合 ==〉 提高光阴极的有效面积 ==〉提高量子效率: 2）采用微通道板作为电子倍增 ==〉 不阻挡光电子 ==〉提高收集效率 Hammamatzu 的 SBA/UBA 光阴极可以得到~40% 光量子效率; 已基本满足要求

新型光电倍增管的研制 知识产权：已申请全球发明专利 与国内有关单位合作研制 55所完成的世界第 一个5”MCP-PMT

小结 BESIII/大亚湾以后的高能物理规划需要大家一起来讨论 中微子物理仍然是一个富矿，值得投入 用反应堆中微子测量mass hierarchy值得深入研究： 科学目标 探测器设计与优化 选址 关键技术预研 欢迎大家参加，欢迎大家批评指正