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Coherent Pion Production induced by neutrino and hadron beam

Coherent Pion Production induced by neutrino and hadron beam. Yasuhiro SAKEMI Research Center for Nuclear Physics (RCNP) Osaka University. Contents Physics motivation Coherent Pion Production Proton induced CPP at RCNP Neutrino beam at J-PARC Summary. D. g’ DD. N -1. D.

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Coherent Pion Production induced by neutrino and hadron beam

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  1. Coherent Pion Production induced by neutrino and hadron beam Yasuhiro SAKEMI Research Center for Nuclear Physics (RCNP) Osaka University • Contents • Physics motivation • Coherent Pion Production • Proton induced CPP at RCNP • Neutrino beam at J-PARC • Summary

  2. D g’DD N-1 D DD interaction in the nuclear medium ~ short range correlation of D-hole: g’DD Hadron beam ~ Low densityNeutrino beam ~ Saturated density Density dependence of g’DD(r) DD interaction in high density

  3. Real Pion D N-1 Virtual Pion : p+* ~ interaction (w,q) Coherent Pion Production Coincidence measurement of pion and external probe Virtual pion prove the pion correlation in the nucleus (n,m-) Nucleus (G.S.) Beam (p,n)

  4. Spin Response in Nuclei n,m- (q,w) p+* s・q p+ p,n Spin Longitudinal Response ~ Pion correlation → maximum M.Ericson

  5. Longitudinal Response ~ Enhancement and Softening → Representing pNN and pND couplings • Transverse Response ~ Quenching and Hardening p-h interaction D-h interaction g’ Longitudinal Response p-h and D-h attractive force from OPEP ~ origin of the pion correlation

  6. Nuclear Structure Model (RPA,…) Effective Interaction: p+r+g’ model g’DD~determine Hadron induced CPP Data RL~Extraction Spin Response Function Input for the analysis of neutrino induced CPP ~ detailed study on reaction mechanism Neutrino induced CPP Data g’DDin saturated density

  7. g’NNσ1・σ2τ1・τ2 g’NΔσ1・S2τ1・T2 g’ΔΔS1・S2T1・T2 N N-1 Δ Δ N-1 N-1 g’NN g’NΔ g’ΔΔ Δ N-1 N N-1 N-1 N Well known from Gamow-Teller resonance Known from Quasi-free scattering Unknown Effective Interaction p+r+g’ model • p+r+g’ model : • Landau-Migdal parameters ~ short range correlation

  8. g’ND=0.3 m*=0.7m g’NN=0.7 m*=0.7m g’NN=0.7 g’ND=0.3 g’NN and g’ND Polarization transfer experiment : Quasi-free 12C(p,n) RCNP: Tp=346 MeV T.Wakasa et al., Phys.Rev.C69, 054609 (2004) LAMPF: Tp=494 MeV T.N.Taddeucci et al., Phys.Rev.Lett.73,3516 (1994) g’NN~0.7, g’ND~0.3

  9. ? g’DD and pion condensation g’DD ~ Sensitive to • Critical density of pion condensation • Cooling mechanism of neutron star ⇒ D propagation in the high density matter g’DD ~ No experimental information

  10. Quasifree Δ decay Nucleon knockout Δ spreading Nucleon spreading CPP • Proton/3He induced CPP : p(3He)+A→n(t)+p++Ag.s. • Neutrino induced CPP : n+A→m-+p++Ag.s. Inclusive process + + QF SP Osterfeld, Udagawa Information on Spin response

  11. Spin longitudinal response CPP ~ forward peaked : Amplitude ~ (S†・q)(S・kp) ~ qkpcosqp Osterfeld, Udagawa qp = 0 degree ~ cross section : maximum ~ Spin longitudinal component → Dominant LO TR 0 degree measurement

  12. Observables Real Pion Coincidence measurement of neutron and pion • Cross section • Spectrum shape • Peak position : ↓ Depend on g’ DD Hole Particle μ-, n , t Osterfeld, Udagawa Nucleus (G.S.) Interaction ~ Virtual Pion q ν, p , 3He • Coherent Pion Production (CPP) • Virtual pion ~ emitted from incidence proton beam • Excite Δ/nucleon-particle nucleon-hole states • Propagate with mixing particle-hole states • Produce the real pion • Target nucleus is left in the Ground State (G.S.) g’ΔΔ=0.33 =0.4 g’DD extraction from CPP

  13. CPP experiments • Hadron probe • KEK (p,n) J.Chiba ~ D peak shift • Saclay (3He,t π+) ~ resolution : not enough to separate ground state • LAMPF (p,n π+) ~ test experiment : shutdown • RCNP (p,n π+) (3He,t π+) ~ in progress • ⇒ study residual interaction with high resolution measurement • Neutrino • A(ν,μ- π+)A • → a few GeV region ~ Data : poor • K2K ~ first data at <1.3 GeV> • J-PARC ! Saclay Data

  14. NPOL2 p detector Target Neutron detector 70 m TOF Proton induced CPP at RCNP Experiment • 12C(p,np+)12C(g.s.) • Beam ~ proton 400MeV • Beam energy resolution ~ DE~100keV • Current ~ 1 nA • Target ~ 12C (100mg/cm2) • Detector • Netron detector ~ DE~300 keV • p detector ~ DE~1 MeV • Identification of CPP • select the ground state of residual nucleus

  15. scintillator Experimental setup Charged particle detector in the sweeping magnet Neutron Counter Tracking detector : GEM Multi-anode PMT ~ set far from magnet through WLS fiber Position sensitive Neutron Counter (liq Sci.) TOF length ~ 70 m Energy resolution : 300 keV Detection efficiency : 15 % @150~400 MeV WLS fiber 10 cm 80 cm

  16. 307.2 50 Tracking Detector • Gas Electron Multiplier detector (GEM) • Charged particle (p..) detection in the magnet • Detector components • Three layers of GEM foil ~ high gain • 2dimentional Readout board ~ high resolution • Specification • high position resolution~ 100mm • Effective area~ 300x50 mm • radiation tolerance • Readout ~ high speed with parallel processing : SpaceWire • Installation ~ completed in the spring of 2006. 140mm 70mmf GEM (supplied by GDD group @ CERN) gain as a function of biased voltage to GEM 2 dimensional Readout Board 200 mmpitch

  17. background TOF spectrum of pion counter Energy loss of two sci. Test Experiment CPP event selection ~ need GEM detector for pion tracking range of CPP event

  18. Preliminary p Cut E/TOF p CPP range RCNP g neutron energy loss (MeV) DE-DE 2 theoretical calculation coherent pion cross section E. Oset, Nucl. Phys. A 592 (1995) 472. Present status • Neutron energy spectrum • CPP region ~ enhancement ? ~ detailed analysis continued • need much more statistics to confirm CPP • Background ~ study in progress • beam halo • Transmission efficiency of the primary beam ~ bad • beam optics tuning ~ considered now • To identify CPP • Separate ground state of residual nucleus by missing mass spectrum ↓ • Tracking information ~ GEM detector is needed next step

  19. Neutrino Nucleus Density r Can not transmit… Hadron Nucleus Neutrino Beam • Weak interaction • Can prove the interior of nucleus • Cross section ~ behave volume like • No distortion/absorption • Adler’s theorem : M~T(π(q)+N→X) Neutrino → Good Probe to study the interior of the nucleus ⇒ keep the information of nuclear interior • Strong interaction • Reaction ~ peripheral • Sensitive to nuclear surface • Distortion/Absorption effects ⇒can investigate residual interaction and response function with high accuracy

  20. A.Hosaka and H.Toki Neutrino Light ions Density dependence of g’ profile function ~ one mean free path S(b) ~ l ~ (Ars)-1

  21. Quasi-free Longitudinal → attractive Transverse → repulsive • Peak ⇒g’DD • Strength⇒ response function Neutrino induced CPP J.Marteau g’NN=0.7, g’ND=0.5, g’DD=0.5

  22. Neutrino induced CPP Coherent Pion Production data ~ not so much data First data from K2K ~ GeV energy region ⇒ NO evidence of CPP

  23. Neutrino Beam at J-PARC Beam energy ~ 1 GeV → suitable for Nuclear Physics in the D resonance region • Detector ~ LOI(AGS neutrino beam) ~ Liquid Sci. with W.L.S • Target • Proton • Carbon ! • Heavy Nucleus Detector design in LOI@AGS n beam Around Near Detector

  24. LOI (AGS neutrino beam) E~1 GeV →D resonance region ~ DD interaction in the nuclear medium ~ p,D propagation in the interior of nucleus Neutrino induced CPP DS physics Nuclear physics ~ DD interaction

  25. Summary • Nuclear physics with Coherent Pion Production • DD interaction in the nuclear medium • Short range correlation : g’DD • Spin longitudinal response function : RL • Hadron(Proton/3He) Beam ~ Prove the surface, low density region • Detailed study of reaction mechanism, response function • Input for the accurate analysis of neutrino induced CPP data • proton induced CPP experiment @RCNP ~ test experiment ~ done • Neutrino Beam ~ Probe the interior of the nucleus • J-PARC neutrino beam ~ 1 GeV ~ suitable for the n-nucleus physics • CPP ~ important to know neutrino detector response ~ RICH Particle ID • Physics discussion, Detector design ~ needed Nuclear Physics ~ DD interaction in the nuclear matter ~ pion condensation, cooling mechanism of neutron star Strange Quark Content in the Nucleon by T.-A. Shibata, N.Saito, Y.Miyachi Neutrino Beam

  26. Longitudinal Response • Enhancement and Softening • Transverse Response • Quenching and Hardening ⊿h-⊿h interaction (g’⊿⊿) ⇒ include Suggested by Prof. M. Sakuda Electron/Photon induced CPP Mixture of longitudinal and transverse responses Transverse excitation ~ dominant Can extract Longitudinal response strength by reducing the Transverse component measured by e/γinduced CPP

  27. GEM detector Sci 2 size: 70um pitch: 140um Sci 1 200um separation position 2 position 1 divide 50.2 charged particle aramid carbon (6μm) trigger Ar+ Drift (3 kV/cm) e- E GEM 1 307.2 ΔV ~400V GEM 2 tracking GEM 3 electron avalanche Readout Board (GND) amp. analog data to ADC charged particle analog LSI mux. Tracking Detector: Gas Electron Multiplier Readout Board

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