研究会 ２００８年４月７ ８日 理研 Neutrino Scattering Experiment, Tokyo Tech Proton Spin Problem and Δs SU(3) flavor symmetry Nucleon Form Factors Neutrino Scattering and Δs E734, MiniBooNE, SciBooNE Model calculation Experiment at J-PARC Summary
Proton spin problem and Δs - EMC results - Nucl. Phys. B38 (1989) 1, Phys. Lett. B06 (1988) 364 Polarized DIS: ' X N Structure Function F i x,q, g i x,q m Parton Distribution q x, Q, q x,q 1 1 1 0 dx g x = 9 a0 1 a3 36 a8 X =0.16±0.01±0.015 SU(3) flavor symmetry 1 P= M,0 p 1 a 3=1.6, a 8=0.58 a 0= u d s=0.1 s= 0.19
Updated results on g1 and Δs Phys. Rev. D 75 (007) 01007 0.9 0.01 g 1 x,5 GeV dx= d 0.0436±0.001±0.018±0.0008±0.006 Assumption: High x contribution = 0 Saturation in the lower x region SU(3) flavor symmetry: s 5 GeV = 0.085±0.013±0.008±0.009 Assuming SU(3) flavor symmetry Phys. Lett. B 647 (007) 8: s = 0.08±0.01±0.0
Flavor tagging in DIS l N l ' h X Structure Function F i x,q, g i x, Q d 3 h h e q x, Q D z, Q q i q dx dz dq z= Parton Distribution P ph E h = P q q x,q, q x,q Flavor Tagging: Hadron carries information on quark flavor P= M,0 h q Fragmentation D z, Q through fragmentation function p h= E h, p h
Strangeness spin inside proton e' h X e N s x =0 - HERMES results - assumed Phys. Rev D 71 (005) 01003 assuming Δq(x)=0 0.6 q= 0.03 dx q x Q =.5 GeV u=0.601±0.039±0.049 d =.6±0.039±0.050 u =.00±0.036±0.03 d =.054±0.033±0.011 s=0.08±0.033±0.009 - without SU(3) symmetry assumption - only partial moments are available - LO extraction
ArXiv:0803.993 submitted to Phys. Rev. Lett Iso-scalar extraction on Δs Charged K multiplicity Inclusive and charged K asymmetries
SU(3) violation and impact on s J. Lichtenstadt and H. J. Lipkin, Phys. Lett. B353 (1995) 119 E. Leader et. al., Phys. Lett. B488 (000) 83 SU(3): symmetry violation cqm calculation: (X. Song et. al, Phys. Rev. D55 (1997) 64-69) SU(3) symmetry: Ds = -0.1 SU(3) breaking: Ds = -0.05
Neutrino-Nucleon scattering F G d Q A±BW ±CW = dq E 1 A = G 1 F F 1 4 F F ] 4[ 1 1 1 4 E Q W= m p mp Q = 4m p 1 G 1 F 1 F 4 1 mp G F F 1 1 16 Q B = C = NC-EL/CC-QE Neutral Current [[ F 1, = [ ] 1 1 s p n p n sin W [ F 1, F 1, sin F F F 1, ] W [ 1, 1. ] s GA GA G 1= z ] s A ] G Q =0 = s
Neutrino scattering and s - E734 results - Neutral current elastic scattering cross section Liquid scintillator + Drift Tube 170 t 0.5E19 POT for neutrino.5e19 POT for anti-neutrino E734, Phys. Rev. D35 (1987) 785 s From G (Q ) to s A GsA Q 0 = s= 0.1±0.10 Further analysis based on E734 R NC /CC =0.15±0.007±0.017 R NC /CC =0.18±0.01±0.03 R NC/ =0.30±0.019±0.037-0.1 < s < 0 0.5 Q 1.0 GeV strong correlation with the axial mass MA Q dependence of GsA
MiniBooNE ν SciBooNE@FNAL Production target
MiniBooNE MiniBooNE active-target: 1 m diameter, ~ 800 tons of mineral oil, CH, 0.86 g/cm3. 180 PMTs (inner tank), 40 PMTs (outer) Detection of scintillation and Cherenkov radiation ν-p, v-n can not be distinguish < 350 MeV/c weak sensitivity on Δs POT: ν 7.5E0, anti-ν.5e0
D.C. Cox, PhD Thesis, Indiana University, 008 Based on 10% of full statistic.
D.C. Cox, PhD Thesis, Indiana University, 008
SciBooNE @ FNAL SciBar/EC detector from KK Muon Range Detector Primary physics goal: precise cross section measurements of non-qe ν-interaction, anti-ν interaction
(NuFact06, H. Tanaka)
SciBar Event Display with KK data NC candidate NC-π0 candidate p p N R NC /CC = n p N Neutron background should be carefully studies. CC-QE candidate
Expected yields With 1E0 POT neutrino 1/3 of FINeSSE (59K) FINeSSE: δ(δs)~0.04 SciBooNE: δ(δs)? With 1E0 anti-neutrino NCE ~ 3k SciBooNE prolongation - One page proposal was submitted to FNAL on Δs measurement as extension of SciBooNE http://www.fnal.gov/directorate/longrange/steering_public/community_letters.html
SciBooNE: status and plan - SciBar and EC were moved from SciBooNE Event Display: KEK to FNAL (Jul. 006) with anti-neutrino beam - Civil construction started (Sep. 006) - Commissioning done (Apr. 007) - Physics RUN : ( May ~ Aug. 007) with anti-neutrino mode 5E19 POT delivered - Detector live time: 96.5% beam - Calibration of the detectors is on going. - Physics RUN with neutrino mode (Oct. 007 ~ ) ~E19 POT delivered neutrino CC-QE candidate - Switch back to anti-neutrino mode (Apr. 008) - R(NC/CC) study is on going.
Accumulated POT by SciBooNE
SciBar Performance Time distribution Event rate per week
nd Vertex Distribution after selection Z Y X Time struc. On-spill 1 track events, fully contained in SciBar + Data MC
Vertex distr. : off-spill Z Y X Time struc. + Off-spill Data MC
Average Energy Deposit (MeV/cm) On-spill MC Before-spill After-spill Track Length (cm)
Nuclear effects on extraction of strange quark component PHYSICAL REVIEW C 76, 055501 (007) Strangeness content of the nucleon in quasielastic neutrino-nucleus reactions N. Jachowicz, P. Vancraeyveld, P. Lava, C. Praet, and J. Ryckebusch
PHYSICAL REVIEW C 76, 055501 (007) Nuclear target: A relativistic mean-field approach FSI: A relativistic multiple-scattering Glauber approach C C
Comparison with other models... PHYSICAL REVIEW C 76, 055501 (007)
Nuclear Effect Q dependence Δs Strange form factors Normalization flux/background Accurate measurement of NC ν-h in 0.1 < Q < 0.4 GeV which is covered by the electron scattering.
J-PARC ν-beam line Beam flux 1 GeV for on-axis < 1GeV for off-axis 101 POT/year (130 days) anti-neutrino beam neutrino anti-neutrino asymmetry measurement Expected ν flux (MC data)
Methods of s measurement Nuclear effect (ex. C target): Nuclear model uncertainty on Ds extraction R(NC/CC) measurements: Neutrino flux should be canceled. It also suppresses the nuclear effect. Is there any model dependence uncertainty? ν-h scattering extraction: Using two targets with different mixture of H and C Separation of n-h and n-c scattering becomes possible Neutrino flux information is needed to extract the cross section.
Extraction of NNCH Nuclear effect free extraction: Using two liquid scintillators with different mixture of H and C: BICRON: H/C BC501A 1.1 BC533 1.96 H NC C NC ρ(g/cm3) 0.874 0.8 BC533 NC BC533 NC N =3.4 N N =.36 N ρh(g/cm3) 0.11 0.080 BC501A NC BC501A NC 0.3 N 3.30 N ρc(g/cm3) 0.688 0.794 ( ~ 15% *NNC ) (FINeSSE: δ(δs)~0.04 with 6E0 POT + 9 t)
Dual SciBath configuration 5m 5 BC501A BC533 WLS readout m 5m Fiducial volume: 3x3x3 m3 Geant4 data ν: 500 MeV p: 70 MeV
FINeSSE SciBath detector FINeSSE Proposal, hep-ex/040007 Liquid Scintillator MC NC elastic event p p WLS readout - Target: C in SciBath - R(NC/CC) measurement cancellation of flux and nuclear effect δ(δs) = 0.04 (sta. + sys.), (+ 0.05 from form factors)
Expected sensitivity 1E1 POT (off-axis) + * 7 t SciBath Stat. + Sys. errors Statistical error only δ(δs) = 0.03 (dipole form factor) Expected sensitivity assuming the dipole approximation: δ(δs) = 0.03 Systematic errors must be studied carefully. (Normalization, Background)
Summary Proton spin problem Δs is a key for understanding of sea quark contribution HERMES, COMPASS: Δs = -0.08 ± 0.0 with SU(3) symmetry HERMES SIDIS: Δs = 0.03 ± 0.03 ( partial, no SU(3) symmetry) Strange nucleon form factor can constrain directly Δs Neutrino scattering: NC elastic scattering E734 NC cross section measurements : -0. < Δs < 0.0 NCEL study at MiniBooNE and SciBooNE MiniBooNE: σnc was extracted based on 10% of the full stat. SciBooNE: Analysis is on-going. FINeSSE proposal δ(δs)~0.04 is based on 3 x (SciBooNE stat).
Summary Δs measurement at J-PARC Measurement of NC cross section on H, not R(NC/CC) Sensitivity study based on 1E1POT neutrino beam at 80m away from the production target Dual SciBath detector δ(δs) ~ 0.03 expected (with dipole form factor assumption) Normalization and background contributions to the systematic error to be studied. Q extrapolation (Q dependence) also has to be carefully studied.
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