What should be considered and improved for CP study.

Transcription

1 P violation Physics at a J-PAR Beam Water herenkov Detector Kenji Kaneyuki Univ. of Tokyo, Institute for osmic Ray Research, Research enter for osmic Neutrinos What should be considered and improved for P study.

2 TK Phase-II 95km <Eν>~0.6GeV J-PAR(JAERI) 50GeV P 0.75MW Phase ~4MW uper-kamiokande.5kt Hyper-Kamiokande ~Mt Tokai Tsukuba disappearance ν e appearance N measurement P violation Proton Decay

3 Next generation Water herenkov neutrino and proton decay detector haracteristics of Water herenkov detector Easy to enlarge Mton class detector Good tracking at ~1GeV Good Particle identification Good Energy resolution Hardware and oftware are already well established.

4 Hyper-Kamiokande uper-k kton ~0.5Megaton fid vol. (0.7Mton x detectors) Needs ~00,000PMTs (assume 40% coverage)

5 Geological map of Kamioka Mine Mozumi Mine uper-kamiokande Tochibora Mine 3km

6 Tochibora Mine Possible site Mostly gneiss

7 ν and ν ν run =15% νμ ν e ν e ν run ν e ν e and ν e contribution in beam flux difference btw and = 15% ν flux : 07a: Ep=30GeV, off-axis.5 degree Decay volume : 110m target diameter : 6mm 5yr= POT (which corresponds to POT at 50GeV)

8 expected event Mton Water herenkov detector events/mton/1mw/yr/50mev expected events w/o ν oscillation expected events with ν oscillation beam beam N N N beam ν e beam Eν(GeV) beam Eν(GeV) N N Eν(GeV) beam ν e beam ν e and ν e in beam should be carefully considered. Eν(GeV)

9 Assumed parameter for this study L=95km (J-PAR Mozumi or Tochibora) m = ev m = ev θ =0.3 θ 3 =0.50 Maltoni, chwetz, Tortolla, Valle, hep-ph/040517, 007 updated

10 ) cos ( ) cos 4( ) cos 4( ) cos 4( 1 ) ( δ + + δ + δ + + δ + = ν ν μ μ P cos ) (1 4 8 ) cos ( 4 8 cos ) cos ( 8 ) (1 1 4 ) ( δ + + δ δ + + = ν ν ν μ E al m a P e ( ) ) ( + = ν ν P e e Oscillation probability ν e ν e ν e = ] [ ] / [ GeV E cm g a ρ [ev ] matter effect solar ν P P conserving

11 Oscillation probability as a function of Eν total matter θ =0.1 θ =0.03 cosδ P solar Eν(GeV) Eν(GeV) L=95km d=π/4

12 P analysis event selection Fully contained event in fiducial volume Evis>100MeV 1 ring e-like no decay electron reconstructed Eν cut e/π 0 separation cosθ μ <0.9 (only for beam) Mπ 0 <100MeV ug latest K M, tools

13 number of events on each step ( beam 1.66MW.yr θ =0.1) ν e ν e signal ν e ( θ =0.1) N N in Fid. (vector) F, in Fid. vol. Evis>100MeV (71%) 1ring 7596 (38%) e-like 1053 (1.4%) no μ-e decay 373 (0.5%) (0.04%) cosθ<0.9 (0.03%) Mπ 0 <100MeV 14 (0.0%) 1845 (4%) 4316 (5.7%) 354 (4.3%) 9 (3.9%) 1008 (1.3%) 7 (1.0%) 340 (0.5%) 4783 (67%) 3005 (4%) 85 (1.%) 33 (0.5%) 0.9 (0.01%) 07 (46%) 354 (%) 45 (8.6%) 0 (7.7%) 70 (%) (%) 0. 5 (0.9%) 4007 (8%) 171 (44%) 1 (43%) 1807 (37%) 455 (9.3%) 394 (8%) 358 (7%) 437 (79%) 77 (50%) 71 (49%) 59 (47%) 0 (4%) (%) 10 (%) 659 (97%) 5779 (86%) 5685 (84%) 548 (78%) 3991 (59%) 35 (5%) 379 (49%)

14 number of events on each step ( beam 1.66MW 7.8yr θ =0.1) νμ ν e ν e signal ν e ( θ =0.1) N N in Fid. (vector) F, in Fid. vol. Evis>100MeV 6585 (74%) 1ring 7443 (31%) e-like 1486 (1.7%) no μ-e decay 586 (0.7%) (0.03%) Mπ 0 <100MeV 9 (0.01%) 0041 (47%) 4878 (11%) 3355 (7.8%) 801 (6.5%) 885 (%) 433 (1%) (71%) 3065 (5%) 56 (1%) 09 (0.4%) 17 (0.0%) (0.0%) (3%) 449 (5.9%) 3319 (8.6%) 3163 (4.5%) 1154 (%) 598 (0.8%) 5498 (85%) 589 (40%) 514 (40%) 076 (3%) 68 (4%) 9 (4%) 3333 (76%) 93 (5%) 47 (51%) 169 (49%) 449 (10%) 391 (9%) 530 (96%) 4783 (87%) 4717 (85%) 4701 (85%) 3568 (65%) 365 (59%)

15 reconstructed E ν distribution beam beam ν e signal N ν e beam ν e signal N N ν e beam ν e beam after all cuts beam : 1.66MW.yr beam : 1.66MW 7.8yr θ =0.1

16 reconstructed cosθ νμ and Mπ 0 distribution beam beam ν e signal ν e signal cosθ νμ N ν e beam N N ν e beam ν e beam This cut is not used for beam : cosθ νμ cosθ νμ beam : 1.66MW.yr Mπ 0 beam : 1.66MW 7.8yr θ =0.1 Mπ 0 Mπ 0

17 reconstructed E ν distribution ( θ =0.1) δ=0 δ=π/ signal+bg νμ+νμ+νe+νe BG νμ+νμ BG signal backgroud δ=0 δ=π/ ν e ν e

18 reconstructed E ν distribution δ=0 δ=π/ ( θ =0.03) signal+bg νμ+νμ+νe+νe BG νμ+νμ BG signal backgroud δ=0 δ=π/ ν e ν e

19 uncertainty for ν e (ν e ) signal reconstructed E ν distribution QE+nonQE nonqe beam Uncertainty flux flux σ(νμ) σ(ν e ) σ(νμ) σ(ν e ) non-qe/qe ND KK δ(n int 1kt )=4.1% δ(nonqe/qe)=~6% δ(n/)=5% Far/near NA61 δ(f/n)=3% beam efficiency energy scale FD δ(e scale)=~% δ(eff)=~5% cancelation between and beam is expected

20 background from and beam beam QE 10% 7% 3% 1π 0 6% 1% 1% 1π ± % 1% % γn 0.8% 0.3% 0% nπ 0.6% 0% 0.5% N elastic 0.% 0.3% % N 1π 0 61% 76% 68% N 1π ± 4% 4% 6% N γn 6% 5% 5% N nπ 10% 6% % mis PID mis PID or π 0 γn mis PID π 0 γn π 0

21 remained BG from and : π 0 1 ring is still missed by e/π 0 separation. Energy of weaker γ γ 1 Fraction ( ) of weaker γ γ 1 +γ opening angle of γ low energy low fraction (MeV) o opening angle vs fraction missed ring is low energy, low energy fraction γ. fraction opening angle 180 o

22 momentum distribution of π 0 BG from, beam BG N 1π 0 N 1π 0 (after cuts) momentum distribution of π 0 background from and beam are similar. beam BG difference of efficiency for π 0 BG from and are canceled. beam BG

23 uncertainty for ( ) backgroud Main Uncertainty flux flux N σ(νμ) N σ(νμ) ND measurement KK δ(n int 1kt )=4.1% δ(n/)=7% Far/near π 0 efficiency NA61 FD cancelation between and beam is expected. We need to improve e/π 0 separation and to understand the performance in detail. δ(f/n)=.7%(0.5-1gev) 3.6%(1-1.5GeV) (HARP) δ(π 0 BG)=+37-6% π 0 mass cut : 19% water property : 11% coh. π model : +3-10%

24 uncertainty for beam ν e and ν e reconstructed E ν distribution ν e in beam QE+nonQE nonqe ν e in beam Uncertainty ν e flux ν e flux σ(νμ) σ(ν e ) σ(νμ) σ(ν e ) non-qe/qe ND Far/near for ν e, ν e NA61 KK δ(n int 1kt )=4.1%( ) δ(nonqe/qe)=~6% δ(π production)=~15% δ(k production)=~16% ν e in beam efficiency FD δ(eff)=~7% We need better understanding of beam ν e, ν e. (measurement at ND, NA61)

25 expected sensitivity 1.66MW 1.1yr+ 3.9yr P sensitivity 1.66MW.yr+ 7.8yr P sensitivity θ Fraction of δ σ 1σ 3σ 3σ δ Fraction of δ θ δ θ systematic error: θ signal 5%, BG 5% These errors are still beam ν e, ν e BG 5% challenging. / 5%

26 summary For P study, and ν e in beam should be carefully considered. Detailed flux and spectrum measurement at ND is necessary. We need to improve e/π 0 separation and to understand its performance in detail at K. We need better understanding of beam ν e and ν e. (measurement at ND, π and K production