The 8 th International Workshop on Chiral Dynamics

The 8 th International Workshop on Chiral Dynamics 2015 Experimental tests of nuclear interaction models in few-nucleon systems Elżbieta Stephan University of Silesia, Katowice, POLAND

System of 3 Nucleons Predictions of NN potentials alone fail to reproduce binding energies of 3 N, 4 N and heavier systems v fail to reproduce minimum of the d(N, N)d elastic scattering cross section v q Introducing concept of three-nucleon forces: genuine (irreducible) interaction of three nucleons q Systematic approach within Ch. PT E. Stephan UŚl PISA - CD 2015

Experimental studies of 3 N Systems ØReactions: v. Elastic scattering: N + d → N + d v. Breakup: N + d → N + N vand electromagnetic processes ØObservables: vdifferential cross section vvector&tensor analyzing powers vpolarization transfer, correlations ØEnergy range - why "medium" and what does it mean? vmeasurable 3 NF effects vbelow pion threshold ØTechnique: vspectrometers vlarge acceptance detectors E. Stephan UŚl PISA - CD 2015

More Dynamical Effects ? Coulomb force and relativity Predictions for the N-d elastic scattering Coulomb 3 NF relativity without C. with C. E=135 Me. V Effects small, located at extreme angles only ! E. Stephan UŚl PISA - CD 2015

3 N Systems – Elastic Scattering Vector & Tensor Analyzing Powers (130 Me. V ) NN is enough • 140 Me. V- K. Sekiguchi et al. , Phys. Rev. C 70, 014001 (2004) • 130 Me. V- H. Mardanpour et al. , Eur. Phys. Jour. 31, 383 (2007), E. Stephan et al. , Phys. Rev. 76 057001 (2007) • 100 Me. VE. Stephan et al. , 3 NF spoils? ? ? ? E. Stephan UŚl PISA - CD 2015

3 N Systems Elastic Nucleon-Deuteron Scattering E. Stephan UŚl Diagram: K. Sekiguchi, FB 20 q Number of observables for the elastic scatterng channel - complete set would provide full dynamical information (at the given energy) q Only fraction has been measured accurately and systematically (RIKEN/RCNP/IUCF/KVI) q Not completely clear picture - still much to explore ! q Complementary studies needed: Nucleon-Deuteron Breakup PISA - CD 2015

3 N Systems- Breakup Reaction q Three nucleons in the final state - 9 variables q Energy-momentum conservation – 4 equations Ø Five independent kinematical variables ü Complete (exclusive) exp. – measured ≥ 5 ü Inclusive exp. – measured ≤ 4 parameters 1 H(d, pp)n measured: directions and energies of two protons, i. e. θ 1, φ 1, E 1 θ 2, φ 2, E 2 E. Stephan UŚl Arclength Variable S PISA - CD 2015

1 H(d, pp)n and 2 H(p, pp)n Breakup Cross Section 3 NF+Coulomb / 3 NF+Relativistic Effects p+d 200 Me. V d+p 130 Me. V (75 Me. V/nucleon) data: Ge. Wall @COSY A. Deltuva et al. , Phys. Rev. C 80, 064002, (2009) H. Witała et al. , Phys. Rev. C 83, 044001, (2011) E. Stephan UŚl PISA - CD 2015

Detection Systems at KVI SALAD ü 140 ΔE-E telescopes ü 3 plane MWPC è angular acceptance: BINA üWall - very similar to SALAD üBall - system of 149 phoswitches è angular acceptance: nearly 4π θ = (12º, 38º), φ = (0º, 360º) E. Stephan UŚl PISA - CD 2015

1 H(d, pp)n and 2 H(p, pp)n Studies at KVI Experiment dp 130 +Ge. Wall dp 100 dp 160 pd 135 pd 190 Beam energy 130 Me. V 65 Me. V/A 100 Me. V 50 Me. V/A 160 Me. V 80 Me. V/A 135 Me. V 190 Me. V Average current 50 p. A 8 p. A 10 p. A Polarization vector & tensor (7 states) vector & tensor (5 states) NO vector (1 state) vector (2 states) Target LH 2 LD 2 BINA W. Parol Ph. D Detector SALAD (Ge. Wall-FZJuelich) BINA q 400 -1000 data points per observable on systematic grid of proton emission angles q Simultaneous measurement of the elastic scattering channel q Part of the data still being analysed E. Stephan UŚl PISA - CD 2015

1 H(d, pp)n Measurement at 130 Me. V Cross Section Results – Highlights Faddeev calculations Realistic NN potentials CD Bonn, Nijm. II, Av 18 3 NF models: TM 99, UIX Coupled channel pot. CD Bonn (mod) + Δ EFT/Ch. PT potentials NNLO – 2 N only NNLO – 2 N + 3 N

1 H(d, pp)n Measurement at 130 Me. V Cross Section Results – 3 NF & Coulomb Effects Including Coulomb force effects improves the agreement with the data at low Erel values The best agreement is reached when both, the Coulomb force and the 3 NF are taken into account ! E. Stephan UŚl PISA - CD 2015

3 N system - 2 H(p, pp)n Breakup Vector (proton) Analyzing Power 190 Me. V, H. Mardanpour et al. 135 Me. V, M. Eslami-Kalantari et al. Ay P

continuation: BINA in Cyclotron Center Bronowice Cyclotron Proteus C-235: q Energy 230 Me. V (degradation down to 70 Me. V) q ΔE/E < 0. 7% q Beam current 500 n. A – 0. 1 n. A E. Stephan UŚl STEPS/ACTIONS: q Installation in CCB (adapting to beam line & infrastructure) q Checks of detectors: repairs, improvements, maintenance q Test run with scintillator detectors; Zn. S, CD 2 targets q Test run with all datectors (including MWPC); Zn. S, CD 2 , CH 2 targets q Liquid target system PISA - CD 2015

Test run: CH 2 vs CD 2 targets CH 2 CD 2 Coincidence trigger: WALL & BALL E. Stephan UŚl PISA - CD 2015

d+p breakup reaction WASA@COSY q q Deuteron beam Energies 340, 380, 400 Me. V Pellet H target WASA detector q forward part: 3 o-18 o q central part: 20 o-169 o E. Stephan UŚl PISA - CD 2015

WASA KVI CCB E. Stephan UŚl PISA - CD 2015

Next step: System of 4 Nucleons v IUCF Ø v KVI - BBS Ø v v d+d elastic scattering at 135 Me. V KVI - BINA Ø d+d -> d+p+n at 135 Me. V Ø d+d -> d+p+n at 160 Me. V G. Khatri Ph. D Considered (CCB): v v d+d elastic scattering at 241 Me. V p+3 He -> d+p+p (and other channels) comparison of dd breakup data for quasi-elastic scattering with pd elastic scattering E. Stephan UŚl PISA - CD 2015

p+d Breakup versus Elastic Scattering Invariant variables based on 4 -momenta of: • in entrance channel: proton deuteron pd, • in exit channel: protons and neutron pn pp , modified to intuitive energy variables pp 1, pp 2 FSI: deuteron treated as proton-neutron pair, elastic scattering treated consistently with breakup E. Stephan UŚl QFS: PISA - CD 2015

Breakup versus Elastic Scattering any relation between the effects? • d+p at 130 Me. V • kinematical points limited to angles and energies of particles registered in SALAD • NN interaction: AV 18 + 3 NF Urbana. IX • effect of adding Coulomb force studied • the largest Coulomb force effects in breakup observed far from elastic scattering E. Stephan UŚl acceptance for el. scatt PISA - CD 2015

1 H(d, pp)n breakup versus elastic scattering any relation between the effects? • d+p at 130 Me. V • kinematical points limited to angles and energies of particles registered in SALAD • NN interaction: AV 18 + Coulomb • effect of adding Urbana. IX 3 NF studied • the 3 NF largest effects in breakup observed in pn FSI region E. Stephan UŚl PISA - CD 2015

Breakup Measurements Summary q Systematic, precise set s of cross sections and analyzing powers basis for comparing different approaches which predict the 3 N system observables q Significant 3 NF effects for cross sections ! q Found large influence of the Coulomb force on c. s. q Relativistic effects to be studied in detail q Discrepancies – hint of missing pieces in dynamic models q Necessary: q further precise and rich data sets, q systematic way of comparing data with calculations q as well as theoretical advances – new Ch. PT ? E. Stephan UŚl PISA - CD 2015

Thank you for attention ! E. Stephan UŚl PISA - CD 2015