Study of threenucleon force with a new experiment of a - PowerPoint PPT Presentation

NSMAT2016 Study of three‐nucleon force with a new experiment of a proton‐deuteron break‐up reaction Yuya Akazawa , M. Fujita, R. Honda 1 , M. Ikeda, H. Kanauchi, K. Kobayashi 1 , T.Koike, K. Miki, K. Miwa, Y. Nakada 1 , S. Ozawa, Y. Sasaki, K. Sekiguchi, H. Tamura Department of Physics, Tohoku University, Sendai , Japan 1 Department of Physics, Osaka University, Osaka, Japan

Contents  Introduction 3NF study ← p‐d break-up reaction • • Detector system “CATCH”  p ‐d reaction experiment @ CYRIC • Experimental condition • Simulated result • Preparation status  Summary

3NF and Neutron star • Importance of Three-Nucleon Force (3NF) for NS neutron matter ρ 0 A. Akmal, et al., PRC58, 1804 (1998) Model dependent 2NF : realistic nuclear potential ⇐ 3000~4000 NN scattering experimental data ⇒ more experimental data needed for 3NF , YN, YY

Study of 3NF by a p‐d break‐up reaction One of the probes to reveal 『 p-d break-up reaction 』 the nature of three-nucleon force (3NF). p + d → p + p + n p 1 E beam = 65 MeV (E 1 ,θ 1 ) [mb/(sr 2 ・ MeV)] θ 1 2NN p beam d target n θ 2 2NF+3NF p 2 (E 2 ,θ 2 ) From side From back p 1 beam S MeV Φ 12 S : correlation between E1 and E2 n p 2 J. Kuros ´ - Z˙ołnierczuk et al., PHYSICAL REVIEW C 66 , 024003 (2002)

Study of 3NF by a p‐d break-up reaction Some observables ・ Energy correlation dependence ・ Reaction angular dependence (θ1,θ2) ・ Φ 12 dependence Experimental data at 130 MeV d beam (θ1,θ2) dependence Φ 12 dependence Φ 12 =180 ° (θ1,θ2)=(15 ° ,15 ° ) 2NF Φ 12 =60 ° Φ 12 =40 ° 2NF+3NF (30 ° ,15 ° ) (25 ° ,15 ° ) ※ θ ± 1 ° , Φ ± 5 ° Φ 12 =120 ° 2NF 2NF+3NF Φ 12 =140 ° (25 ° ,20 ° ) (30 ° ,20 ° ) S (MeV) S (MeV) S. Kistryn et al., Phys. Lett. B 641 , 23 (2006). S. Kistryn et al., Phys. Rev. C 68 , 054004 (2003). Detector with a large angle acceptance for multi-particles is required

Current experimental data of p‐d reactions 関口さん RIKEN, RCNP, KVI, IUCF MeV/nucleon beam 80 MeV 80 MeV [1] K. Bodek et al., Few Body Syst. 30, 65 65 (2001) Courtesy of K. Sekiguchi [2] St. Kistryn, et al., Phys. Rev. C 68 , 054004 (2003) [3] H. Mardanpour, et al., Nucl. Phys. A 790 (2007), p. 426c etc. ⇒ new data points with our new detector system next page As the first step, we will take data with an 80 MeV p beam.

“CATCH” We will use this detector system for the p-d experiment. C ylindrical A ctive T racker and C alorimeter system for H yperon-proton scattering Cylindrical Fiber Tracker ・ surrounding a target ・ 8 layers of scintillation fibers ・ three dimensional tracking ⇒ measure the scattering angle (σ=1 ° ) and the energy deposit (σ=20%@1MeV) BGO calorimeter ・ surrounding the CFT ・ 24 BGO crystals Production finished soon (30 × 25 × 400mm 3 ) are used Advantages ⇒ measure the kinetic energy ・ Large acceptance ( ∵ surrounding the target) (σ=1%@80MeV) ・ Many sets of (θ 1 ,θ 2 ,Φ 12 ) in one experimental setup ・ Multiple particle detection ・ Particle ID (p/d/μ ・ π )

“CATCH” We will use this detector system for the p-d experiment. C ylindrical A ctive T racker and C alorimeter system for H yperon-proton scattering Prototype results of pp, pC scattering experiment d Production finished soon Δ E(Fiber) [MeV] Advantages p ・ Large acceptance ( ∵ surrounding the target) ・ Many sets of (θ 1 ,θ 2 ,Φ 12 ) in one experimental setup Cosmic ray ・ Multiple particle detection ・ Particle ID (p/d/μ ・ π ) E(BGO) [MeV]

p-d experiment @ CYRIC • Experimental condition • Simulated result • Preparation status

p‐d reaction experiment with CATCH Commissioning of the CATCH system Purpose Measurement of dσ / dΩ of the p-d elastic scattering and break-up reaction ⇒ new data for 3NF Experimental setup To be performed at CYRIC, Tohoku Univ. in January 2017 Elastic scattering Break-up reaction n p’ p D 2 gas target p beam p beam 300 mm(t) 80 MeV 80 MeV CFT p d’ BGO calorimeter Simulation Event identification for elastic scattering and break-up reaction

Simulation: p‐d elastic scattering Simulation Event generation: p - d elastic scattering kinematics. p ’ Detector: CATCH configuration pd 散乱も 80 MeV のデータは ※ Energy resolution is taken into account. シミュレーション結 beam 未測定 ⇒ ② -3 果 (pd break-up) d ’ Event ID Particle ID Simulated result ( pd elastic) Simulated result ( pd elastic) CFT Δ E [MeV] E(CFT+BGO) [MeV] Kinematically calculated E p ’ (θ) E d’ (θ) d p θ [deg.] Total E [MeV]  Identification of elastic scattering events  p and d are clearly separated . using the kinematically calculated energy.

Simulation: p‐d break-up reaction Missing Mass (Event ID) Event generation : p - d break-up reaction Simulated result pd → ppX MassX p pd 散乱も 80 MeV のデータは  break-up reaction can beam シミュレーション結 reconstructed from 未測定 ⇒ ② -3 be identified using 果 (pd break-up) the two protons p Missing Mass of n n Missing Mass Ep1 vs Ep2 Uniquely determined correlation Simulated result (pd break-up) θ 1=55 ± 2.5 ° E p2 [MeV] θ 2=60 ± 2.5 ° Φ=180 ± 10 ° Selecting (θ 1 ,θ 2 ,Φ 12 ) S axis S MeV dσ / dΩ can be obtained p _{low E} can’t be tracked. as a function of S for various combinations E p1 [MeV] of (θ 1 ,θ 2 ,Φ 12 )  Energy acceptance ： higher than 20 MeV for both Ep1 & Ep2 ※ threshold can be decreased for several combinations of (θ ,θ ,E ,E

Status of CATCH CFT BGO 4 straight + Half part 4 spiral layers (14 crystals) 400mm 400mm BGO calorimeter is ready Completed an assembly of CFT Energy resolution σ E ≃ 1% last week !! for 80 MeV p Angular resolution σ θ ≃ 1 ° (prototype) Satisfactory Efficiency ≃ 98% (3 rd straight layer) performance ≃ 96% (3 rd spiral layer) Two systems will be combined into CATCH next month

CATCH the new horizon p-d reaction experiments with CATCH is just a starting point Baryon-Baryon interaction 3NF Σ p scattering p-d , p- 3 He , etc … CATCH + spectrometers elastic scattering & break-up Cylindrically Active Tracker and Calorimeter system for Originally designed to be used for Hyperon-proton scattering experiment this experiment in J-PARC n p ’ beam p Λp scattering p 400 mm 3NF (T=3/2) To be studied after commissioning of CATCH e same method as ∑ p scattering except for

Summary • 3NF study for neutron star - p-d elastic scattering and break-up reaction are one of the probes. - d σ/dΩ of p-d reaction at 80 MeV beam will be new data. • New detector system CATCH - Suitable for this experiment because of its large acceptance - Consisting of a Cylindrical Fiber Tracker and BGO calorimeters - The first operation and application • Simulation - p / d are clearly discriminated. - p-d elastic scattering & break-up reaction are identified from the kinematics and missing mass • Preparation - CATCH will be all constructed next month. ⇒ The experiment will be performed in Jan. 2017

If you have ideas or interests, please contact us. • CATCH specification  z acceptance = 400 [mm]  Energy acceptance 5 ~ 180 [MeV] ※ exchanging or adding crystals ⇒ maximum can be increased  Energy resolution σ E (BGO) = 1% for 80 MeV σ E (CFT) = 20 % for 1MeV  Angular resolution σ θ ≃ 1 °  Time resolution(CFT) σ time ≃ 1 [ns]  Particle ID : p/d/ μ,e,π ※ depends on particle energy