Study for the Neutrino Coherent Pion Production Experiment

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1 Study for the Neutrino Coherent Pion Production Experiment Yasuhiro SAKEMI Research Center for Nuclear Physics (RCNP) Osaka University Contents Phycis motivation Coherent Pion Production Proton induced CPP Neutrino beam at J-PARC Summary

2 Phase Transition in Nuclear Matter Phase transition of nuclear matter Pion condensation ~ Bose-Einstein condensation in the high density nuclear matter Kaon condensation..?

3 Physics motivation Temperature : T Phase Transition Tc = 200 MeV RHIC & LHC Quark-Gluon Plasma Deconfinement & Chiral transition Nuclear Force: V(r) (MeV) Nuclear Force Region Region Region Nuclear Force V( 1 S 0 ) Pion compton wavelength ~ Nuclear force range GSI SIS ?? Neutron star Color superconductor Distance: r (fm) Vacuum Normal Density 0 =0.12(fm -3 ) Pion condensation phase Nuclear Density : (fm -3 ) Quark/Gluon 2 Critical density of phase transition into Pion Condensation phase Precursor of Pion Condensation ~ Enhancement of Nuclear Response Function related pion Study on Short range component of Nuclear Force with Neutrino Beam

4 Nuclear force and Pion condensation z Nuclear force ~ short range correlation of the nuclear interaction ¾ 1π + 1ρ + g (short range: phenomenological parameter) k2 (σ 1 k )(σ 2 k )τ 1 τ 2 = 4πf 2 g ' NN ω k mπ 2 fρ k2 2 (σ 1 k )(σ 2 k )τ 1 τ 2 = 4πf g ' NN f k m ω ρ V ph longitudinal V ph transverse z Landau-Migdal parameters: g ~ g NN. g N, g g NNσ1 σ2τ1 τ2 g NN N N N-1 Well known from Gamow-Teller resonance g NΔσ1 S2τ1 T2 g NΔ Δ N-1 N N-1 Known from Quasi-free scattering N-1 Δ g ΔΔS1 S2T1 T2 g ΔΔ Δ N-1 N-1 Unknown z Critical density of Pion condensation phase transition ¾ Sensitive to g ¾ Determine the g from Coherent Pion Production g

5 Coherent Pion Production A(, - + )A(Ground State) Nuclear Force ~ g Inclusive measurement CPP spreading Quasifree decay Nucleon spreading Nucleon knockout Coincidence measurement of neutron and pion -, n, t Hole Interaction ~ Virtual Pion q, p, 3 He Particle Real Pion Nucleus (G.S.) Coherent Pion Production (CPP) -Virtual pion ~ emitted from incidence proton beam -Excite /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.) Observables Cross section Spectrum shape Peak position : E g' hcf m Depend on g Osterfeld, Udagawa πn 2 π ρ 0 g =0.33 =0.4

6 Neutrino Density Nucleus Neutrino Beam Weak interaction Can prove the interior of nucleus Cross section ~ behave volume like No distortion/absorption Adler s theorem : M~T( (q)+n X) Cross section, shape and peak position ~ g Osterfeld, Udagawa Neutrino r Good Probe to study the interior of the nucleus keep the information of nuclear interior Longitudinal response Transverse response Hadron Can not transmit Nucleus Strong interaction Reaction ~ peripheral Sensitive to nuclear surface Distortion/Absorption effects can investigate residual interaction with high accuracy

7 Electron/Photon induced CPP Suggested by Prof. M. Sakuda Longitudinal Response R L n σ q0 2 Mixture of longitudinal and transverse responses Enhancement and Softening Transverse Response R T n σ q0 2 Quenching and Hardening h- h interaction (g ) include Transverse excitation ~ dominant Can extract Longitudinal response strength by reducing the Transverse component measured by e/ induced CPP

8 Neutrino induced CPP J.Marteau Quasi-free Longitudinal attractive Transverse repulsive Peak g Strength Precursor of pion condensation

9 Density dependence of g Neutrino Light ions A.Hosaka and H.Toki

10 Coherent Pion Production at RCNP g DD ~ extract from Coherent Pion Production p + A n A (g.s.) 1. Peak shift from N-D residual interaction E g (ћcf pnd /m p 2 ) 0 2. Longitudinal response function (R L ) ~ dominant at 0 degree s cpp (0 ) R L g (g NN, g ND, g DD ) CPP status Saclay 12 C(3He,t + ) 12 C(G.S.)~resolution poor/shutdown LAMPF 12 C(p,n + ) 12 C(G.S.)~ test experiment / shutdown RCNP 12 C(p,n + ) 12 C(G.S.)~ in progress Experiment Beam ~ proton 400MeV un-polarized E~100keV Target ~ 12 C (100mg/cm 2 ) Detector Netron detector ~ E~300 kev detector ~ E~1 MeV Identification of CPP select the ground state of residual nucleus RCNP coherent pion cross section[2]. g =0.33 =0.4 correlation of cross section and g [3]. [2] E. Oset, Nucl. Phys. A 592 (1995) 472. [3] T. Udagawa et al., Phys. Rev. C 49 (1994) 6.

11 Neutron Counter CPP Experiment NPOL2 100 m Position sensitive Neutron Counter (liq Sci.) Energy resolution : 300 kev Detection efficiency : 20 % Neutron TOF ws Ring Cyclotron target ( 12 C) Pion detection ~ GEM pion counter 50 < E pi < 150 MeV AVF Cyclotron coincidence AVF Cyclotron Facility

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

13 Experimental status CPP event selection ~ need GEM detector for pion tracking background TOF spectrum of pion counter range of CPP event Trigger sci.

14 Neutrino induced CPP Coherent Pion Production data ~ poor First data from K2K ~ GeV energy region NO eveidence of CPP

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

16 Neutrino induced CPP E=1 GeV resonance region ~, propagation in the interior of nucleus LOI (AGS neutrino beam) fm 2 /MeV

17 Summary Nuclear physics with Neutrino Beam zunderstand Neutrino-Nucleus reaction mechanism znew probe ~ Neutrino at J-PARC ¾Eν~1 GeV : properties in nucleus zcoherent Pion Production ¾Neutrino Beam ~ Probe the interior of the nucleus ¾ Proton/3He Beam ~ Prove the surface, Reaction mechanism ¾Electron Beam ~ Transverse response function zphysics discussion, Detector design Strange Quark Content in the Nucleon by T.-A. Shibata, N.Saito, Y.Miyachi Phase transitions in the neutron star ~ cooling mechanism ~ depend on g Neutrino Beam

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