利用太阳中微子研究太阳金属丰度 唐晓东 中国科学院近代物理研究所 JUNO 中微子天文和天体物理学研讨会,7 月 日, 高能所

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1 利用太阳中微子研究太阳金属丰度 唐晓东 中国科学院近代物理研究所 JUNO 中微子天文和天体物理学研讨会,7 月 日, 高能所

2 Outline Short history of solar neutrino Solar metallicity problem Key nuclear physics parameters Work done by LUNA at Gran Sasso Jinping Underground lab for Nuclear Astrophysics (JUNA) and its possible contributions

3 Solar Neutrinos are our 007! 4 1 H 4 He + 2 e n e (~ 25 MeV) n

4 Exp Target Data/S SM Homestake Kamiokande 37 Cl 0.33± 0.03 water 0.57± 0.07 Homestake C 2 Cl 4 (Chemistry) KAMIOKANDE-II H 2 O(Cherenkov) The Nobel Prize in Physics 2002 "for pioneering contributions to astrophysics, in particular for the detection of cosmic neutrinos"

5 The neutrino image of the Sun with Super-Kamiokande Credit: R. Svoboda and K. Gordan (LSU)

6 Solar Neutrino Problem Solar model Important cross sections: 3 He( 3 He,2p) 4 He, 3 He( 4 He,g) 7 Be, 7 Be(p,g) 8 B Unknown neutrino physics-neutrino oscillation??? "Most likely, the solar neutrino problem has nothing to do with particle physics. It is a great triumph that astrophysicists are able to predict the number of 8 B neutrinos to within a factor of 2 or 3... Howard Georgi and Michael Luke (1990)

7 Direct Measurement with 7 Be target (1960-) Si detector a particle from 8 B 7 Be(p,g) 8 B 7 Be(53.12 d) 8 B(0.77s) Radioactive Target (small target size, radiation) 7 Be target atom number Beam-target inhomogeneity Solid Angle of Si proton beam 7 Be target A. Junghans et al., PRC 68, (2003)

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9 Neutrino Oscillation Kamiokande Observatory, ICRR (Institute for Cosmic Ray Research), The University of Tokyo n e 0.57*Solar Model n e,n m,n t 8 B Fluxes at SNO (2001) n e,n m,n t The Sudbury Neutrino Observatory 0.32*Solar Model (10 6 cm -2 s -1 ) n e : 1.75±0.15 n mt : 3.69±1.13 n total : 5.44±0.99 n SSM : /-0.81

10 For three decades people had been pointing at this guy and saying this is the guy who wrongly calculated the flux of neutrinos from the sun, and suddenly that wasn't so. It was like a person who had been sentenced for some heinous crime, and then a DNA test is made and it's found that he isn't guilty. That's exactly the way I felt. John Bahcall ( ), Dancing with neutrinos

11 Solar Spectrum by NOAO

12 solar metallicity puzzle New 3D hydrodynamic models of the solar atmosphere Parameter free significantly improving consistency of line analysis Makes sun more consistent with similar stars in local neighborhood But abundances in the photosphere significantly reduced Z: M. Asplund et al., Annu. Rev. Astro. Astrophys. 47 (2009) 481

13 Better determined metallicity leads to problems Sound-speed profile SSM with new lower metallicity SSM with old metallicity Sound speed Precision 10-4 SSM: standard solar model Serenelli, Haxton, Peñay-Garay (2011)

14 Solar Neutrinos are our 007! 4 1 H 4 He + 2 e n e (~ 25 MeV) n

15 pp-i chain

16 pp Chains within the Sun ~T 4 ~T 11 ~T 22

17 CNO bi-cycle 1 ~0.5% Making ~1% energy only In CNO-I, 14 N(p,g) 15 O controls the flow rate

18 F( 8 B)~10 6 cm -2 s -1 F( 13 N) ~F( 15 O) ~10 8 cm -2 s -1

19 Observation of CNO n by Borexino CNO n First observation of pep n. However, only upper limit was established for CNO n. cpd/100 tons

20 Adapted from Haxton s presentation

21 国际重要地下实验室比较 600m Soudan 美国 700m Y2L 800m 韩国 Canfranc 西班牙 1000m Kamioka 日本 tunnel mine 1100m Boulby 英国 1400m INO 印度 1400m LNGS 意大利 1600m Baksan 俄罗斯 1700m Modane 法国 1500m DUSEL 美国 2300m 2000m SNO 加拿大 2400m CJPL 中国

22 What need to be measured Borexino, SNO+,(Jinping?) Haxton, Roberson and Serenelli, arxiv: v1 (2012)

23 measured to 2% by SuperKamiokande (the solar thermometer) Haxton, Roberson and Serenelli, arxiv: v1 (2012)

24 what we want to know: the primordial core abundance of C + N (in units of SSM best value) Haxton, Roberson and Serenelli, arxiv: v1 (2012)

25 the entire solar model dependence: luminosity, metalicity, solar age, etc., Haxton, Roberson and Serenelli, arxiv: v1 (2012)

26 Determined by SNO and KamLAND Haxton, Roberson and Serenelli, arxiv: v1 (2012)

27 Nuclear Physics is the iggest uncertainty! 7 Be(p,g) 8 B (5.5%) 14 N(p,g) 15 O (7.2%) Haxton, Roberson and Serenelli, arxiv: v1 (2012)

28 14 N(p,g) 15 O : slowest reaction in the CN cycle Fuel Primary Products Secondary products Approximate temperature (10 9 K) Hydrogen 4 He 14 N yr Approximate duration Massive star Sun Massive MS stars: energy production and their lifetime

29 Age Estimates of Globular Clusters in the Milky Way Constraints on Cosmology A group of stars with same initial chemical composition same age, different masses Smaller 14 N(p,g) rate Larger 14 N(p,g) rate G. Imbriani et al., A&A 420, 625 (2004) Lower limit on the age of the Universe : 11.2 Gy (95% C.L.) Krauss and Chaboyer, Science 299:65 (2003)

30 Measurement of CNO neutrino Would test our understanding of hydrogen fusion as it occurs in main sequence stars substantially more massive than the Sun. adapted from W. Haxton s presentation

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32 Extrapolation and its risk Adopted from Cauldrons in Cosmos

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34 Problems in current direct measurements Cosmic and Room Background 3 MeV < E g < 8 MeV: Beam induced background 0.5 Counts/s Above the ground Counts/s LUNA: underground

35 South Dakota School of Mines & Technology - NUCLEAR ASTROPHYSICS Adapted from F. Strieder s talk 35

36 Backgrounds at the lowest energy days 928 C Beam induced background LUNA Collaboration / Nuclear Physics A 779 (2006)

37 S t (0)=1.61±0.18 kev b Only ~50% of old value Old measurement Old extrapolation 14 N(p,g) n cno reduced by 2 with 8% error (precise core metallicity) Globular cluster age increased by Gy Phys. Lett. B591 (2004) 61-68/Nuclear Physics A 779 (2006)

38 Event/day Challenging the tiny cross sections ground:~8x10-3 n/cm 2 /s Background at ground LUNA:reduced by 1000 Background under ground E cm CJPL:reduced by 10,000

39 CJPL-II JUNA(Jinping Underground laboratory for Nuclear Astrophysics) Traffic tunnel JUNA Gran Sasso : 180,000 m /7/12 volume:~200,000 m 3 4 groups, 8 experimental halls( 65x12x12m 3 ) 39

40 CJPL-II Traffic Tunnel Headrace 四个 14m*14m*130m 隧道 容积 :13 万立米, 比 CJPL 一期大 30 倍 现在已经开建 Science, Nov. 30,

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42 Jinping Accelerator:First deep underground accelerator driven by ECR 400 kv accelerator Intensity 2014, JUNA formed 2015, NSFC: RMB 20 millions CAS : RMB 5 millions CNNC : RMB 3 millions : construction of lab and accelerator : 19Fe(p,a), 25Mg(p,g), 13C(a,n) and 12C(a,g) JUNA core institutes:ciae,imp,tsinghua, Shanghai JiaoTonng,Sichuan; Other JUNA members:tanihata, Kubono, Alex Heger, Maria Lugaro, Yongzhong Qian, Wanpeng Tan, Dongmin Mei JJUNA 400 kv LUNA 400 kv CASPAR Ion source 2.45 GHz ECR RF source RF source H + >10 ma 1 ma 0.1 ma He + >10 ma 0.5 ma 0.1 ma He 2+ ~2.5 ma N/A N/A JUNA

43 JUNA organization CIAE IMP THU SJTU SCU SDU SZU PI Group leader Weiping Liu 12 C(a,g) 16 O Xiaodong Tang 13 C(a,n) 16 O Ion source Zhihong Li 25 Mg(p,g) 26 Al Jianjun He 19 F(p,a) 16 O Gang Lian Accelerator 14 N(p,g) 15 O

44 JUNA international team Osaka,Isao Tanihata Monash,Alexander Heger Notre Dame,Wanpeng Tan HAS,Maria Lugaro Minisota,Yongzhong Qian RIKEN,Shigeru Kubono South Dakota,Dongming Mei

45 JUNA IAC M. Wiescher Chair UND T. Motobayashi Member RIKEN H. Wang Member TCAS C. Brune Member Ohio M. Junker Member INFN D. Robertson Member UND F. Strieder Member SDSMT D. Leitner Member LBL Q. Yue Member THU /17

46 Accelerator and ion source design 46

47 Comparison with other experiments 13 C(a,n) 16 O J JUNA Excellent background First deep underground accelerator driven by ECR Detected bk. (evt/day) He beam intensity (pma) Time for reaching 20% statistical err. (Ecm=0.2 MeV) Highly sensitive fast n detector signal/bk. Stuggart ,000 yrs / CASPAR (USA) yrs / LUNA (Italy) yrs 190/530 JUNA days 57/8 Reaction Rate=7 evt/day/pma;10% det. Eff. ; signal=total-background;rel. err. =Sqrt(total+bk)/signal

48 Better measurement with JUNA Jinping: background/10 Signal*10 Rel err 1/10 Better data Lower energy days at Gan Sasso LUNA Collaboration / Nuclear Physics A 779 (2006)

49 Summary Better understanding with higher precision Or New physics Neutrino physics Astronomy Good luck! JUNO and JUNA Nuclear Physics Astrophysics