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Study of Light  - Hypernuclei by Spectroscopy of Two Body Weak Decay Pions

Study of Light  - Hypernuclei by Spectroscopy of Two Body Weak Decay Pions. (Update for E12-10-001). Fragmentation of Hypernuclei and Mesonic Decay inside Nucleus Free:  p +  - 2-B: A  Z  A (Z + 1) +  -. Liguang Tang

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Study of Light  - Hypernuclei by Spectroscopy of Two Body Weak Decay Pions

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  1. Study of Light -Hypernuclei by Spectroscopy of Two Body Weak Decay Pions (Update for E12-10-001) Fragmentation of Hypernuclei and Mesonic Decay inside Nucleus Free:  p + - 2-B: AZ  A(Z + 1) + - • Liguang Tang • Department of Physics, Hampton University • Jefferson National Laboratory (JLAB) Hall A Collaboration Meeting, June 9-10, 2011, JLAB

  2. Decay Pion Spectroscopy to Study -Hypernuclei Direct Production e’ Example: K+ 12C e * Ground state doublet of 12B B and  p  12B  E.M. 12Bg.s. Hypernuclear States: s (or p) coupled to low lying core nucleus 2- ~150 keV 1- 0.0 -  12C Weak mesonictwo body decay

  3. Decay Pion Spectroscopy for Light and Exotic -Hypernuclei Fragmentation Process Example: e’ K+ Access to variety of light and exotic hypernuclei, some of which cannot be produced or measured precisely by other means 12C e * Fragmentation (<10-16s) p s 12B* 4H  4Hg.s. Highly Excited Hypernuclear States: s coupled to High-Lying core nucleus, i.e. particle hole at s orbit   -  Weak mesonictwo body decay (~10-10s)   4He

  4. E12-10-001: Study of Light Hypernuclei by Pionic Decay at JlabTechnique and Precision • Light hypernuclei which stop primarily in thin target foil • Weak 2 body mesonic decay at rest uniquely connects the decay pion momentum to the well known structure of the decay nucleus, B and spin-parity of the ground state of hyperfragment • Decay pionspectroscopy can be accurately measured and variety of physics may be extracted • Most of the background particles move forward, thus pion momentum spectrum is expected to be clean with minor 3-boby decay pions plus some from  decay • Precision and accuracy do not depend on the precisions of beam energy and tagged kaons • The momentum resolution can be at level of ~170keV/c FWHM, powerful in resolving close-by states and different hypernuclei • Bcan be determined with accuracyat a level of 20keV • The experiment can be carried out in parasitic mode with high precision hypernuclear mass spectroscopy experiment which measures the level structures of the primary hypernuclei, as long as the two share the same target E12-10-001 update @ Hall A Collaboration Meeting, June 9-10, 2011, JLAB

  5. E12-10-001: Study of Light Hypernuclei by Pionic Decay at JlabMajor Physics Objectives Precisely determine the single  binding energy B for the ground state of variety of light hypernuclei: 3H,4H, ..., 11Be, 11B and12B , i.e. A = 3 – 12 (few body to p shell). Determine the spin-parity Jpof the ground state of these light hypernuclei Measure CSB’s from multiple pairs of mirror hypernuclei such as: 6He and6Li, 8Li and8Be, 10Be and10B. CSB can also be determined by combining with the existing emulsion result for hypernuclei not measured in this experiment. Search for the neutron drip line limit hypernuclei such as: 6H, 7H and 8H which have high Isospin and significant - coupling. May also extract B(E2) and B(M1) electromagnetic branching ratios through observation of the isomeric low lying states and their lifetimes. The high precision makes these above into a set of crucial and extremely valuable physics variables which are longed for determination of the correct models needed in description of the Y-N and Y-Nucleus interactions. E12-10-001 update @ Hall A Collaboration Meeting, June 9-10, 2011, JLAB

  6. E12-10-001: Study of Light Hypernuclei by Pionic Decay at JlabIllustration on the Main Features Experimental Tech. & layout Example HRS - Hadron Comparison of Spectroscopic and Background - Production (Example) SPECTROSCOPY Light Hypernuclei to Be Investigated K+ e e Septum p * - K+ e p  A1Z1 stop Lucite Č (b) Additions from 9Li and its continuum (Phase II: 9Be target) e’ 6 3/2+ AZ - 1/2+ Jp=? 1- A2Z2 Hodoscope 7Li A(Z-1) A1(Z1+1) 8He HRS - Electron 9Li Drift Chamber 8Li 5 (Z-1) = Z1+Z2; A=A1+A2 Trigger I: HRS(K) & Enge() for Decay Pion Spectroscopy Experiment Trigger II: HRS(K) & HRS(e’) for Mass Spectroscopy Experiment 6Li 1/2+ VS 7H 3B background 1-? 5/2+ 3/2+ 2- 4 BACKGROUND e Previously measured e Ex Ex Ex 0 0 0 1 1 1 * 3 Mirror pairs K+ Ex 0 2 - p(n) ,(-) 64mg/cm2 N 2 AZ (A-1)Z’ 22mg/cm2 K+ 10B 8Be 8B 9Li 8H 7He 6He 9B 8He 3H 6Li 10Li 12B 9He 7Li 9Be 5H 4H 6H 8Li 7H 11Be 11B 10Be 1 - A 2 6 7 11 12 8 1 5 3 4 9 10 E12-10-001 update @ Hall A Collaboration Meeting, June 9-10, 2011, JLAB

  7. Illustration of Decay Pion Spectroscopy Additions from 12B and its continuum (Phase III: 12C target) (c) 1- 12B 9Be 10Be 8Be 9B 11B 10Li 9He 11Be 8H Jp=? 10B 5/2+ 3B background 8B (b) Additions from 9Li and its continuum (Phase II: 9Be target) 3/2+ 1/2+ 1- 7Li 8He 9Li 8Li 6Li 1/2+ 7H 3B background 1-? 5/2+ 3/2+ 2- Ex Ex Ex (a) 0 0 0 1 1 1 2-B decay from 7He and its continuum (Phase I: 7Li target) Ex 0 2 1-? 0+ 1/2+ 3H 6He 1/2+ 6H 4H 7He 3B background 3/2+ 5H 5/2+ Ex PMax PMin Ex 2 0 0 2 90.0 100.0 110.0 120.0 130.0 140.0 - Momentum (MeV/c)

  8. Feasibility Test Run at MAMI by A1 Collaboration - Spec-C e’ Beam KAOS K+

  9. MAMI Run Status • The first beam period (Commissioning) • May 24 to June 14, 2011 • Maximum beam current: 1.5A • KAOS detector system needs to be further optimized in order to run with high intensity run (50 A) • Pion arm proven to be clean and low single rate • Run is still undergoing • The second period (implement e’ detector) • July 19 to July 31, 2011 • The third possible beam period (higher intensity) • November to December, 2011 • In general, the physics yield rate at MAMI is about 6 times smaller than that at JLAB

  10. Summary • High intensity CW beam at JLAB and the characters of electro-production make possible for high precision hypernuclear programs, among which the decay pion program is unique. • The decay pion spectroscopy program is able to provide precise and fundamental information needed to understand the YN and Y-Nucleus interactions. • Unlike the mass spectroscopy program, this program does not request precision and stability on beam energy. • Test run at MAMI is undergoing

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