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Feasibility study of neutrino charged-current reaction cross sections at J-PARC

Feasibility study of neutrino charged-current reaction cross sections at J-PARC. IPNS, KEK Nobuaki Imai. n SNS. http://www.phy.ornl.gov/nusns. Contents. Scientific motivation KARMEN experiment @ISIS Decay-at-Rest neutrinos Detectors @ n SNS Yield estimation @ J-PARC

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Feasibility study of neutrino charged-current reaction cross sections at J-PARC

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  1. Feasibility study of neutrino charged-current reaction cross sections at J-PARC IPNS, KEK Nobuaki Imai 宇宙核物理連絡協議会 WS

  2. nSNS • http://www.phy.ornl.gov/nusns 宇宙核物理連絡協議会 WS

  3. Contents • Scientific motivation • KARMEN experiment@ISIS • Decay-at-Rest neutrinos • Detectors @ nSNS • Yield estimation @ J-PARC • Background estimation @ nSNS • Nuclear & particle physics interests 宇宙核物理連絡協議会 WS

  4. ~ 10% Scientific motivation Delayed supernovae explosion SN1987A Neutrino is a key player. neutrino luminosity energy spectrum angular distribution From nSNS proposal 宇宙核物理連絡協議会 WS

  5. Direct measurement -KARMEN experiment- • Pulsed Decay at Rest neutrinos • Active target 12C 6x3.5x3.2m3 liquid scint. module x512 • Veto counter Iron shield 18cm thick 180t anti-detector (plastic) x96 outer shield detector x 120 B. Zaitnitz, Prog. Part. Nucl. Phys. Vol.32 pp351 宇宙核物理連絡協議会 WS

  6. Result of KARMEN experiment 4399 Coulomb (3years) = Yn3.0x1013n/cm2 @ 17.5m 12C(ne,e-)12Ng.s 223.2+/-13.5 events [8.9+/-0.6+/-0.75]10-42 cm2 12C(ne,e-)12N* 206+/-46 events [6.4+/-1.45+/-1.4]10-42 cm2 12C(n,n’)12C* [10.8+/-1.1+/-1.2]10-42 cm2 B. Zaitnitz, Prog. Part. Nucl. Phys. Vol.32 pp351 宇宙核物理連絡協議会 WS

  7. capture ～99% τ～2.2 μs νμ τ～26 ns p νμ Hg νe π+ μ+ π- e+ < 52.6 MeV 30 MeV Decay-at-rest neutrino FREE 1 GeV 宇宙核物理連絡協議会 WS

  8. νμ, νμ, ντ, ντ Super nova 3.5 ν-SNS νe 3 νe νμ 2.5 2 Luminosity (×1051 erg/s) νμ νe 1.5 1 0.5 0 0 10 20 30 40 50 60 70 80 Energy (MeV) Energy spectrum of DAR-n 宇宙核物理連絡協議会 WS

  9. ~ 2 × 107 (νe+νμ+νμ)/cm2/s DARn-Flux@J-PARC Yn(J-PARC) ~10Yn(ISIS) @ 20m 宇宙核物理連絡協議会 WS

  10. (νe,e-) : charged current AZ+1N-1 W± e- νe detect AZN Detectors @ nSNS Solid target: Fe, Al, Pb… Liquid target: C (paraffin), O (water), d (heavy water)… 宇宙核物理連絡協議会 WS

  11. Solid target detector • mass~ 10 t • easy exchange • time resolution~ severalns • 3D-trackingand PI • energy resolution~ severalMeV Corrugated target Fed=0.75 mm 10 t Segmented detectors Drift tube14,200 radius8 mm、length3 m tube: metal-vapored mylar gas: CF4 (84 ns for 8 mm) charge division: tracking Fidusial volume:2.0×2.0×3.0 m3 宇宙核物理連絡協議会 WS

  12. Liquid target detector Fiducial volume3.5 × 3.5 × 3.5 m3 Ring-imaging Cherenkov detector Liquid target 8-inch PMTs#600 　　　　　　→　41% surface coverage Hamamatsu R5912 σq ~ 0.6 photon、σt ~ 1.2 ns 宇宙核物理連絡協議会 WS

  13. (D) 1 m (C) } Measurements at the same time 　　→　Normalization (A) 3.5 m (B) 0.5 m 0.5 m Detector setup • Solid target 2 m (B) Liquid target 3.5 m (C) Fe Shield (D) Veto counters 宇宙核物理連絡協議会 WS

  14. Yield estimation @ J-PARC • ν flux2×107 /s/cm2 @ 20m • Fe10 t σ～2.5×10-40cm2　→　46 events/day efficiency (PI, veto system dead time) ~30% 　　　　　　　　　　　　→　15 events/day(~3000 events/year) • Liquid target (volume15.5 m3) paraffinCnH2n+2 (n~20),ρ=0.85 g/cm3 σ=9.3×10-42 cm2for X=Ngs σ=5.1×10-42 cm2 for X=N* 　　　　　　→　2,800 events/year 　　　　　　→　1,260 events/year (ε=40%) 宇宙核物理連絡協議会 WS

  15. Backgrounds @ SNS N from SNS ~3×109 events/day　→　remove by time structure(>1.2 μs) From cosmic rays μ130 Hz/m2 ~2.5×108 events/day n~2.6 Hz/m2 ~5.0×106 events/day Fe 10 t　→　~10 evts/day@ full power 宇宙核物理連絡協議会 WS

  16. Reduction of cosmic ray backgrounds Cosmicray n 5×106/day　→　3×103/day　→　30/day　→ Reduction by PI ~ 1/10 time window (<10μs) Fe shield (top1 m, wall0.5 m) Cosmic ray μ 2.5×108/day　→　1.5×105/day　→　1.5×103/day　→ Reduction by PI ~ 1/1000 time window (<10μs) Vetocounters (ε=99%) μ + Feshield　→　n + X 30 n /day　→ ~ 1/10 Reductiion by PI 宇宙核物理連絡協議会 WS

  17. Schedule 2009~ Background n measurement : N. Imai Detector development : Y.X. Watanabe 宇宙核物理連絡協議会 WS

  18. Nuclear physics interest • GTのdirect measurement 1. Determination of geff 2. (p,n)反応では分からない30MeV程度の励起状態での forbidden transition • 12C(nm,m-)12N sexp~10 x10-42 cm2stheo.~20x10-42 cm2 Where is the origin of the deviation ? 宇宙核物理連絡協議会 WS

  19. Search for this reaction Particle physicsinterest 1. Leptonflavor number violation normal: rare decay(10-4): 2. Search for scalar and tensor term 宇宙核物理連絡協議会 WS

  20. Theoretical calculation; (ne,e-) GF: Fermi constant qc: Cabbibo angle Ee,ke: energy and momentum of outgoing electron F(Z+1,Ee): distortion of outgoing electron wave function by Coulomb field gAeff: effective axial-vector coupling constant 宇宙核物理連絡協議会 WS ZA(m,e-)

  21. Uncertainty of theoretical calc. 1. Treatment of F(Z+1,Ee) ~50% 2. gAeff(~-10%)? <-> quenching of B(GT) 3. Distribution of excited states(20-30%) cf.) up to L~4 contribution Fermi function +relativistic effect Fermi function C. Volpe et al., PRC65, 044603 宇宙核物理連絡協議会 WS

  22. Indirect measurement • Charge exchange reaction (3He,t), (p,n)reaction DS=1, DL=0 -> B(GT) (1) High multipolarities ? (2) Theory dependence (a) Normalization by b-decay (b) Reaction theory is needed Direct measurement 宇宙核物理連絡協議会 WS

  23. n observatory • SK : • KAMLAND: • SNO: • HOMESTAKE: 16O+n反応は測定されているはず。 宇宙核物理連絡協議会 WS

  24. n-12C reactions @KARMEN • 12C(ne,e-)12Ng.s.Ee- < 35 MeV 12C+e++ne Ee+ < 15 MeV e-とe+のdelayed coin: 時間、エネルギー、場所 • 12C(ne,e-)12N* 11C+p Ee- > 17 MeV • 12C(n,n’)12C*(1+;T=1,15.1 MeV) 12Cg.s. + g (Eg=15.1MeV) 宇宙核物理連絡協議会 WS

  25. Mass dependence 宇宙核物理連絡協議会 WS

  26. νμ νμ, νe Time structure of DAR-n flux Pulsed proton beam 25 Hz (40 ms) 1 ms Intensity 1014p beam 1 MW (average) 2000 1500 1000 500 0 Suppression ~ 2.5e-5 Time (ns) 宇宙核物理連絡協議会 WS

  27. Site @ MLF • 3GeV, 333mA 70m 150m 宇宙核物理連絡協議会 WS

  28. νe : charged current pure neutral current neutral current + charged current AZ+1N-1 W± νμ νμ e- νe neutral current 検出 強度 charged current νμ, νe νμ、νμ : neutral current AZ*N AZN AZN beam Z0 decay νμ 2000 1500 1000 500 0 時間 (ns) 検出 ビーム由来バック・グラウンド大 ν-N反応 宇宙核物理連絡協議会 WS

  29. (D) 1 m (C) (A) 3.5 m (B) 0.5 m 0.5 m veto 60 cm 長さ 4.5 m 2 m Scint.(thickness1 cm)4 layers Feabsorber(thickness1.5 cm) 3 layers 3.5 m • ≧ 2 photons/layer • ≧ 3 layer hits μ~99.5 % γ~0.005 % n~0.07 % false veto <10%　→　dead time 宇宙核物理連絡協議会 WS

  30. 2000 3 νe e- 1500 2 Counts (a.u.) 強度 (a.u.) 1000 1 500 0 0 0 10 20 30 40 50 60 70 80 0 10 20 30 40 50 Energy (MeV) Energy (MeV) 2000 1500 e- 1000 Counts (a.u.) 500 0 0 2 4 6 8 10 12 14 16 18 20 セル数 固体標的検出器 νe + Fe　→　e- + X セルのヒット数　→　飛程　→　PI、e-のエネルギー Fe標的　10 トン σ～2.5×10-40cm2　→　46 events/day efficiency (PI, veto system dead time) ~30% 　　　　　　　　　　　　→　15 events/day ~3000 events/year 宇宙核物理連絡協議会 WS

  31. 200 150 N (PMTs) 100 50 0 1500 1000 Q (PE) 500 25 25 30 35 40 45 50 Energy (MeV) 液体標的検出器 νe + C　→　e- + X 28 光電子/MeV エネルギー分解能　　5~7%at53 MeV 位置分解能　　　　　　15~20 cm 角度分解能　　　　　　3~5° 流動パラフィン CnH2n+2 (n~20),ρ=0.85 g/cm3 ν flux2×107 /s/cm2 σ=9.3×10-42 cm2for X=Ngs σ=5.1×10-42 cm2 for X=N* 　　　　　　→　180 events/year/m3 　　　　　　→　2,800 events/year (標的体積 15.5 m3) 　　　　　　→　1,260 events/year (ε=40%) 宇宙核物理連絡協議会 WS

  32. 強度 νμ beam νμ, νe 2000 1500 1000 500 0 時間 (ns) 宇宙線起源のバック・グラウンドの除去 • 時間構造 < 10 μs • Feシールド 　　天井　1 m、壁　0.5 m • 粒子識別 　　三次元飛跡測定 • vetoシステム τ ~ 2.2 μs 宇宙核物理連絡協議会 WS

  33. + time window (>1.2μs) B.G. ~ 10% セル・ヒット数 セル・ヒット数 セル・ヒット数 セル・ヒット数 セル・ヒット数 セル・ヒット数 セル・ヒット数 ν- N反応 n from SNS 宇宙線μ 宇宙線n 固体標的検出器でのバック・グラウンド除去 + 検出器外縁部8cmに信号無し ゲート無し + time window (<10μs) + <ΔE> < 10 keV + vetoシステム + コンパクト 宇宙核物理連絡協議会 WS

  34. 4He(n,n’X) reaction Sp=20.6 MeV Sp=19.8 MeV 4He(n,n’)4He* 3He+n 3H+p s~10x10-42 cm2 Gas検出器(1atm,300K) KARMEN 0.86/13.89=6.2x10-2 mol/cm3 gas 検出器　1./22.4x103=4.5x10-5 mol/cm3 n-flux x10 3 GeV 330mA P x10 10 atmで動くgas検出器 V x1012 m x 6.4 m x 7 m の大検出器 NO STATE 4He X10-3

  35. 4He(n,e-)4Li reaction 4He(n,e-)4Li Q=-23.41 MeV 4Li 3He+p Q=3.1 MeV 4He(n,e+)4H Q=-24.01 MeV 4H 3H+n Q=2.98 MeV Eb < 30 MeV Gas検出器の周りを10cm厚の プラスチックシンチで覆う。 E4Li < 0.35 MeV E(3He) = 0.75 MeV/u = 8mm/10atm 4He

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