Neutron-Proton Asymmetry Dependence of Spectroscopic Factors Jenny - PowerPoint PPT Presentation

Neutron-Proton Asymmetry Dependence of Spectroscopic Factors Jenny Lee The University of Hong Kong JCNP Symposium Nov 7-12, 2015

惠州 Hong Kong Huizhou HIAF ~ 100 km Beijing Shanghai Tokyo University of Hong Kong First Nuclear Physics Hong Kong Group in 2014

International Workshop on Neutron-Proton Correlations & 12 th RIBF Discussion July 7-12, 2015 The University of Hong Kong

HKU Group Members Jenny Lee Zhengyu Xu Xinxing Xu Sylvain Leblond (Postdoc) (Postdoc) (Postdoc) Ph.D. Univ. of Tokyo Ph.D. CIAE Ph.D. Univ. of Caen External Members for Data Analysis Hongna Liu (PhD student, Peking Univ.) Yelei Sun Jiajian Liu Taras Lokotko (Research Assistant) (PhD student) (PhD student) Ph.D. Peking Univ. M.S. Shenzhen Univ. M.S. Univ. of Paris

Nuclear Experimental Programs @ HKU Correlation Effect on a Nucleon (Direct Reactions) • One-nucleon knockout at 250 MeV/u (RIKEN, JL et al., paper in preparation) • Knockout of 14 O at 60 MeV/u (RCNP, Y. Sun et al., paper in preparation) • ( p,d ) Transfer of 34,46 Ar at 70 MeV/u (MSU, J. Manfredi, data in analysis) Neutron-Proton Correlations (Direct Reactions) • Systematic np - & nn - transfer reactions on sd -shell nuclei (RCNP, Y. Ayyad et al., paper in prep) • Exclusive np -knockout of 12 C at 200 MeV/u (RIKEN, H. Liu et al., paper in preparation) • ( p,pNN ) at GeV (IMP, Lanzhou, Proposal) Alpha-cluster Correlations (Direct Reactions) • ( p,p α ) of neutron-rich Be (RIKEN, T. Lokotko PhD) Nuclear Structure Nuclear Structure (in-beam gamma spectroscopy) (β -dacay spectroscopy) • 30 Ne (RIKEN, H. Liu et al., paper in preparation) • 53,55,56 Ca (RIKEN, J. Liu PhD) • 173,174 Er (RIKEN, J. Liu in analysis) • 77 Ni (RIKEN, Z. Xu et al., paper in preparation) Detectors: DALI2 upgrade • 69,71,73 Co (RIKEN, T. Lokotko, data in analysis) (60 NaI(Tl) detectors) • 100 Sn (RIKEN, Proposal)

Nucleon Correlations Truncated shell model space + effective interactions Greater In reality distribution of nucleons to Short-range, higher energy Few active tensor & configuration orbitals collective High correlations Reduction in Occupancy Occupancy Inert Core Inert Core Probing the nuclear wave function Removing nucleon from occupied orbital  Cross sections (probability) depend on the single-particle occupancy & overlap of many-body wave functions

Spectroscopic Factor (SF) How good the effective interaction in Cross Sections Reaction Model Shell Model can describe the correlations ? Spectroscopic Factors (expt) Quantify Occupancy  Correlation Effects SM description is accurate How much ? What is the Isospin Some correlations missing in the Dependence of nucleon correlations? interactions ? ( e,e’p ) – Stable nuclei (near closed shell) • Constant ~30-40% of SF reduction compared to theory • Correlations missing in interactions used in SM L. Lapikas, Nucl. Phys. A553, 297c (1993) ( e,e’p ) reactions Extend SF measurements to Exotic Nuclei !

Isospin Dependence of Shell Occupancies? Q: Isospin Dependence ? SF(expt)/SF(theory) Knockout reactions: Yes & Strong A. Gade et al., Phys. Rev. Lett. 93, 042501 (2004) Phys. Rev. C 77, 044306 (2008) & reference therein Transfer reactions: Weak p( 34,36,46 Ar,d) at 33 A MeV J. Lee et al., Phys. Rev. Lett 104, 112701 (2010) Systematic difference between two probes ! Incompatibility  Incomplete understanding in underlying reaction mechanism Transfer Reaction  NSCL: 34,46 Ar(p,d) at 70 A MeV - same energy as knockout reactions for direct comparison

Transfer Reactions for Correlation Studies 34, 46 Ar + p →d + 33, 45 Ar @ 70 MeV/u National Superconducting Cyclotron Laboratory Michigan State University deuteron East Lansing, Michigan, USA Completed in December 2014 (analyzed by Juan Manfredi) CH 2 θ 34,46 Ar Beam 33, 45 Ar To S800 Φ Spectrograph MCP P,E, Φ Primary Devices 1. High Resolution Array (HiRA) 2. S800 Spectrograph 3. Multi-Channel Plates (MCP)

Isospin Dependence of Shell Occupancies? Q: Isospin Dependence ? SF(expt)/SF(theory) Knockout reactions: Yes & Strong A. Gade et al., Phys. Rev. Lett. 93, 042501 (2004) Phys. Rev. C 77, 044306 (2008) & reference therein Transfer reactions: Weak p( 34,36,46 Ar,d) at 33 A MeV J. Lee et al., Phys. Rev. Lett 104, 112701 (2010) Systematic difference between two probes ! Incompatibility  Incomplete understanding in underlying reaction mechanism Transfer Reaction Knockout Reaction ?  NSCL 09084: 34,46 Ar(p,d) at 70 A MeV - same energy as knockout reactions for direct comparison

Knockout Reaction Mechanism Deeply-bound Weakly-bound Reaction Theory: Eikonal & Sudden Approximations R s = s exp / s theo SF(expt)/SF(theory) J. Tostevin et al., J. Phys. G, Part. Phys. 25, 735 (1999) Reactions ~ 70 MeV/u Target 9 Be or 12 12 C Core re 14 O(d,t) Projectile (fast beam) Δ S=S n -S p (MeV) 1. Invariant with beam energy ?  Data at energies of 200-300 MeV/A NSCL, MSU - 14 O knockout at 60 MeV/u F. Flavigny et al., Phys. Rev. Lett. 108, 252501 (2012)

One Nucleon Knockout Reaction on 30 Ne @ 230 MeV/u RIKEN H. Liu, J. Lee, P. Doornenbal, H. Scheit, S. Takeuchi, N. Aoi, K. Li, M. Matsushita1, D. Steppenbeck1, H. Wang, H. Baba, E. Ideguchi,, T.Motobayashi, H. Sakurai, M. Takechi, Y. Togano Tokyo Tech. CNS/ Unvi. Of Tokyo Y. Kondo, N. Kobayashi, T. Nakamura S. Michimasa Theory Collaboration: RCNP/Osaka University Hokkaido University K. Minomo, K, Ogata M. Kimura JAEA Univ. of Surrey J. A. Tostevin, E.C. Simpson Y. Utsuno

1N-Knockout of nuclei with large Δ S at 230 AMeV 30 Ne: | Δ S| ~ 20 MeV Beam: 30 Ne @ ~ 230 A MeV 1n-knockout : 30 Ne  29 Ne 48 Ca beam 345MeV/u 1p-knockout : 30 Ne  29 F ~75pnA DALI2 ( γ -ray detection) 12 C target 2.54g/cm 2 9 Be ZDS: ZeroDegree target (15mm) Spectroscometer BigRIPS (Beam PID) (fragment PID & 30 Ne 228MeV/u ~440 cps Purity: 63% momentum measurement)

γ detection Array - DALI2 Reaction Beam Product Target γ -ray • 186 NaI(Tl) detectors • ∆ E/E ≈ 11 % at 250 MeV/u • θ coverage 11° to 165° • ≈ 20 % FEP efficiency at 1MeV S. Takeuchi et al., NIMA. 763, 596 (2014)

Gamma Spectrum of 29 F & Cross Sections P. Doornenbel et al., paper in preparation ZDS SM : sd-pf model space with the SDPF-M effective interaction ( Y. Utsuno ) AMD : Antisymmetrized molecular dynamics with Gogny D1S interaction ( M. Kimura ) Inclusive σ : 5.8 (3) mb Ground-state σ : 5.2 (3) mb γ -energy threshold: 200 keV

Gamma Spectrum of 29 Ne 12 C( 30 Ne, 29 Ne + γ ) X ZDS C excitation 622(4) Counts/ 10keV SeGA @ NSCL 232(6) 35 Published in NNDC Fit function: Response functions(GEANT4) 15 931(8) + Exponential background * Difference between fitting results with & without C excitation  Systematic error

Gamma Spectrum & Cross Sections 𝝉 (mb) E level (keV) Inc. 62(2) < 200 25(4) 231 11(2) 625 24(2) 923 2.2(0.4)* * Lower limit γ - γ coincidence analysis: direct transition to “ g.s .” γ -energy threshold: 200 keV H. Liu, JL et al., paper in preparation

Comparison to Theoretical Cross Sections ERT: Eikonal reaction theory with an extension of the continuum- discretized coupled-channels method (CDCC) K. Minomo, K. Ogata R s = σ exp /σ theo Assuming g.s. 3/2 + Rs = 0.51 (SM) and 0.36 (AMD) 29 Ne: σ (<200 keV) : 25 (4) mb P//  3/2 + : 14 mb, 3/2 - : 11 mb Assuming g.s. 3/2 - Rs = 0.59 (SM) and 0.39 (AMD) 29 F: g.s. σ : 5.2 (3) mb Rs =0.31 (SM) and 0.54 (AMD) M. Yahiro et al., Prog. Theor. Phys. 126, 167-176 (2011), Prog. Theor. Exp. Phys. 2012, 01A206 (2012). K. Minomo et al., Phys. Rev. C 90, 027601 (2014)

30 Ne: | Δ S| ~ 20 MeV 12 C( 30 Ne, 29 Ne)X Deeply-bound Weakly-bound ~230 AMeV R s = s exp / s theo Assuming 12 C( 30 Ne, 29 F)X g.s. 3/2 + ~230 AMeV Both SM & AMD over-predict Large Reduction as data <90 AMeV g.s. SFs  interactions need to  Discrepancy not due to invalidity be improved of reaction model at low-energy

Knockout Reaction Mechanism Deeply-bound Weakly-bound 2. Inert-core ? R s = s exp / s theo SF(expt)/SF(theory) Reactions ~ 70 MeV/u Mult ltip iple le scat atter ering ing/ Core re excit itat atio ion Direc ect KO Evapo apora ratio ion Intranuclear Cascade Model ( INC ) 14 O(d,t) Δ S=S n -S p (MeV) INC: Significant core-excitation process NSCL, MSU - 14 O knockout at 60 MeV/A depletes the one-neutron removal channel F. Flavigny et al., Phys. Rev. Lett. 108, 252501 (2012) Understanding the knockout reaction mechanism needed !

Studies of Single-Nucleon Correlations using Knockout Reactions Experiment at RCNP, Osaka University (Japan) RIKEN J. Lee, H . Liu, G. Lorusso, S. Nishimura, S. Takeuchi, J. Wu, Z. Xu Peking University Y. Ye, J. Chen, Y. Ge, Z. Li, J. Lou, R. Qiao, Y. Sun RCNP N. Aoi, Y. Ayyad, T. Hashimoto, E. Ideguchi, H.J. Ong, J. Tanaka, M. Tanaka, T. Trong, H. Suzuki, T. Yamamoto Y. Sun, J. Chen (PKU) – Support (local + travel expense) by RCNP Young- Researcher Program + Supervision during 8-month / 3-month stay at RCNP

Study of Reaction Mechanism Fully Exclusive Measurements of reaction products 14 O + 12 C  13 N + p 大阪大学・核物理研究中心  13 O + n Osaka University Research  12 N + p Center for Nuclear Physics  11 C + 2p EN-Course Beam line Hodoscope K400 Ring Cyclotron pol p 400 MeV 3 He 140 A MeV Light heavy ion 100 A MeV Si Array p RIKEN: Hodoscope K140 AVF Cyclotron Peking University: Si Array