Liguang Tang Department of Physics, Hampton University Jefferson National Laboratory (JLAB) PAC35, January 25, 2010, JLAB Mesonic Decay inside Nucleus Free:  p +  - Free:  p +  - 2-B: A  Z  A (Z + 1) +  -

e e’ ** K+K+  p A (A-1) Quasi-free  production (Continuum) e e’ ** K+K+  p A Y (A-1) Production of Hyperfragment (Continuum) N e e’ ** K+K+  p AaAa (A a -1) Production of Hyperfragment (Continuum) AbAb N Y (A b -1) e e’ ** K+K+  p A YAYA Direct production of Hypernuclei Background A rich source of a variety of light hypernuclei for new findings and discoveries 2B decay pion is used as the tool

p e’ e 12 C K+K+  12  B g.s. 12 C g.s.  - Weak mesonic two body decay ~150 keV Ground state doublet of 12  B B  and  Direct Production Example:

p e’ e 12 C  12  B * K+K+ 4 He  - Weak mesonic two body decay (~ s) Access to variety of light and exotic hypernuclei, some of which cannot be produced or measured precisely by other means    4H4H Fragmentation (< s) Fragmentation Process Example:

7 Li(K - stop,  - ) 7  Li 7 Be spectroscopy from: 7  Li  7 Be +  - Spin/parity: 1/ C(K - stop,  - ) 12  C 12  C(p)  11  B + p S P 11 C spectroscopy from: 11  B  11 C +  - Spin/parity: 5/2 + ?

 High precision on ground state light hypernuclei  Resolution: ~130 keV FWHM; mass precision : < ± 30 keV  Precise  binding energy  Charge symmetry breaking  Linkage between structures of hypernuclei and nuclei  Determining ground state spin/parity  Search for Isomeric low lying states ( Isomerism )  Study the drip line limit on  -hypernuclei, such as heavy hyper-hydrogen: 6  H, 7  H, and 8  H  Medium modification of baryon property – B(M1) from lifetime of ground and low lying isomeric states of hypernuclei These are rich and the most fundamental but so far unobtainable information needed for building the correct models for YN and Y-Nucleus interactions

Figure 6. Schematic top view of the experimental configuration for the JLAB hypernuclear decay pion spectroscopy experiment (Hall A). Hall Z-axis To Hall Dump K+K+ -- 22mg/cm 2 64mg/cm 2 To a local photon dump HES 94 – 140 MeV/c 2.3 GeV 1.2 GeV/c Ideal if HKS and HES move to Hall A

e e’e’e’e’ Hodoscope Lucite Č Drift Chamber ---- K+K+K+K+ HRS - Hadron HRS - Electron Septum Trigger I: HRS(K) – Enge(  ) - Decay Pion Experiment Trigger II: HRS(K) – HRS(e’) - Spectroscopy Experiment

Quasi-free   p +  - (all) Within the HES acceptances

Example: 4  He  3 He + p +  - P  Acceptance

Breakup ModeQ value (MeV)  - Decay P  (MeV/c)Width (keV/c) FWHM 7  He- 7 Li +  p + 6  H (B  =5.1) 6 He +  n + 6  He Li +  d + 5  H (B  =4.1) 5 He +  ~900 * 3 H + 4  H He +  H + 3  H He +  Two-Body decay – 6 possible hypernuclei Breakup ModeQ value (MeV)  - Decay P  max (MeV/c) – cut off d + 5  H (B  =4.1) 4 He + n +  * 2n + 5  He He + p +  n + 4  He He + p +  Three-Body decay – Background

Breakup ModeQ value (MeV)  - Decay P  (MeV/c)Width (keV/c) FWHM 9  Li- 9 Be +  p + 8  He Li +  n + 8  Li Be +  p + 7  H (B  =6.1) 7 He +  ~270 * d + 7  He Li +  § 2n + 7  Li Be +  He + 6  H (B  =5.1) 6 He +  § 3 H + 6  He Li +  § 3n + 6  Li Be +  ~220 **  + 5  H (B  =4.1) 5 He +  ~900 *§ n +  + 4  H He +  § 6 He + 3  H He +  § Two-Body decay – 6 additional hypernuclei

Breakup ModeQ value (MeV)  - Decay P  (MeV/c)Width (keV/c) FWHM 12  B- 12 C +  p + 11  Be (B  =10.5) 11 B +  n + 11  B C +  p + 10  Li (B  =12.3) 10 Be +  d + 10  Be B +  n + 10  B C +  p + 9  He (B  =7.8) 9 Li +  He + 9  Li Be +  § 3 H + 9  Be B +  * 3n + 9  B C +  p + 8  H (B  =7.1) 8 He +  Li + 8  He Li +  §  + 8  Li Be +  § 4 H + 8  Be B +  n + 8  B (B  =6.7) 8 C +  ** p + 4 Li + 7  H (B  =6.1) 7 He +  ~270 *§ 5 Li + 7  He Li +  § 5 He + 7  Li Be +  § 6 Be + 6  H (B  =5.1) 6 He +  § 6 Li + 6  He Li +  § 6 He + 6  Li Be +  ~220 **§ 7 Be + 5  H (B  =4.1) 5 He +  ~900 *§ 2  + 4  H He +  § 9 Be + 3  H He +  § Two-Body decay – 12 additional hypernuclei

(a) 2-B decay from 7  He and its continuum (Phase I: 7 Li target) 1/2 + HES P Max HES P Min 0 2 ExEx ExEx 0 2 4H4H  He 1/2 + 3/2 + 5/2 + 3H3H 6  He 1- ?1- ? 6H6H 5H5H  - Momentum (MeV/c) 3B background (b) 3B background 2 0 ExEx 1 0 ExEx 1 0 ExEx 1 0 ExEx /2 + 5/2 + 1/2 + 9  Li 8  He J p =?  Li 7H7H 1/2 + 3/2 + 7  Li 1- ?1- ? 6  Li Additions from 9  Li and its continuum (Phase II: 9 Be target) (c) Additions from 12  B and its continuum (Phase III: 12 C target) 12  B  Be 11  B 10  Li 10  Be 5/2 + J p =? 10  B J p =? 9  He J p =? 9  Be 1/2 + 9  B J p =? 8H8H 8  Be 8B8B 3B background J p =? Illustration of Decay Pion Spectroscopy A p H3H 4H4H 5H5H 6H6H 7H7H 8H8H 6  He 7  He 8  He 9  He 6  Li 7  Li 8  Li 9  Li 10  Li 11  Be 9  Be 10  Be 8  Be 11  B 9B9B 10  B 8B8B 12  B Light Hypernuclei to Be Investigated Previously measured Mirror pairs

Study of Light Hypernuclei by Pionic Decay at JLab M. Christy, C. Keppel, M. Kohl, Liguang Tang ( spokesperson ), L. Yuan ( spokesperson ), L. Zhu, Hampton University, USA N. Grigoryan, S. Knyazyan, A. Margaryan ( spokesperson ), L. Parlakyan, S. Zhamkochyan, H. Vardanyan, Yerevan Physics Institute, Armenia O. Hashimoto, S.N. Nakamura ( spokesperson ), Tohoku University, Japan P. Baturin, W. Boeglin, P. Markowitz, J. Reinhold ( spokesperson ), Florida International University, USA P. Bosted, K. de Jager, R. Ent, H. Fenker, D. Gaskell, T. Horn, M. Jones, J. LeRose ( spokesperson ), G. Smith, W. Vulcan, S.A. Wood, JLAB, USA E. Cisbani, F. Cusanno, S. Frullani, F. Garibaldi ( spokesperson ), M.L. Magliozzi, Istituto Nazionale di Fisica Nucleare, Sezione di Roma, Italy Ed.V. Hungerford, Department of Physics, University of Houston, USA L. Majling, Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Czech Republic B. Gibson, Los Alamos National Laboratory, USA T. Motoba, Laboratory of Physics, Osaka Electro-Comm. University, Japan B. Hu, J. Shen, W. Wang, X. Zhang, Y. Zhang, Nuclear Physics Institute, Lanzhou University, China D. Androic, M. Furic, T. Petkovic, T. Seva, University of Zagreb, Croatia A. Ahmidouch, S. Danagoulian, A. Gasparian, North Carolina A&T State University, USA G. Niculescu, I. Niculescu, James Madison University, USA M. Iodice, Istituto Nazionale di Fisica Nucleare, Italy G.M. Urciuoli, Istituto Nazionale di Fisica Nucleare, Sezione di Roma1, Italy R. De Leo, L. Lagamba, S. Marrone, Istituto Nazionale di Fisica Nucleare, Italy H.J.Schulze, Istituto Nazionale di Fisica Nucleare, Italy J. Feng, Y. Fu, J. Zhou, S. Zhou, China Institute of Atomic Energy, China Y. Jiang, H. Lu, X. Yan, Y. Ye, P. Zhu, University of Science & Technology of China, China.

 High quality and high intensity CW CEBAF beam at JLAB made possible for high precision hypernuclear programs, among which the decay pion program is unique.  The decay pion spectroscopy program will provide precise and fundamental information needed to significantly improve our understanding on YN and Y-Nucleus interactions.  A test run in the 6GeV period is important for the development of this program for the 12GeV period.  Unlike the mass spectroscopy program, this program does not request precision and stability on beam energy.