1 E05-115: Third Generation Hypernuclear Experiment Hall C User Meeting January 18th, 2008 (Fri) Yu Fujii Tohoku Univ. E : Spectroscopic investigation of  hypernuclei in the wide mass region using the (e,e’K + ) reaction

JLab E05–115 collaborators in proposal ~ 87 researchers from 19 institiutes Dept. of Phys. Tohoku Univ. Y. Fujii, O. Hashimoto, H. Kanda, M. Kaneta, D. Kawama, K. Maeda, N. Maruyama, A. Matsumura, S.N. Nakamura, K. Nonaka, Y. Okayasu, M. Sumihama, H. Tamura, K. Tsukada, Y. Miyagi Dept. of Phys. Hampton Univ. O.K. Baker, L. Cole, M. Christy, P. Gueye, C. Jayalath, C. Keppel, S. Malace, E.K. Segbefia, L. Tang, V. Tvaskis, L. Yuan Dept. of Phys. Florida International Univ. A.Acha, W. Boeglin, L. Kramer, P. Markowitz, N. Perez, B. Raue, J. Reinhold, R. Rivera Dept. of Phys. Yamagata Univ. S. Kato Institute of Particle and Nuclear Physics (KEK) H. Noumi, Y. Sato, T. Takahashi Laboratory of Phys, Osaka Electro-Comm. Univ. T. Motoba Dept. of Phys. Univ. of Houston Ed. V. Hungerford, K.J. Lan, Y. Li, N. Elhayari, S. Randeniya, N. Klantrains Thomas Jefferson National Accelerator Facility P. Bosted, R. Carlini, V. Dharmawardane, R. Ent, H. Fenker, D. Gaskell, M. Jones, D. Mack, J. Roche, G. Smith, W. Vulcan, S. Wood, C. Yan Yerevan Physics Institute R. Asaturyan, H. Mkrtchyan, A. Margaryan, S. Stepanyan, V. Tadevosyan Nuclear Physics InstituteLanzhou Univ. X. Chen, B. Hu, S. Hu, Y. Song, W. Luo, B. Wang Dept. of Physics / Applied Phys. Univ. of Zagreb D. Androic, M. Furic, T. Petkovic, M. Planinic, T. Seva Dept. of Phys. North Carolina A&T State Univ. A. Ahmidouch, S. Danagoulian, A. Gasparian Dept. of Phys. Louisiana Tech Univ. N. Simicevic, S. Wells Dept. of Phys. James Madison Univ. G. Niculescu, M.-I. Niculescu Dept. of Phys. Univ. of North Carolina at Wilmington L. Gan Dept. of Phys. Duke Univ. M.W. Ahmed Dept. of Phys. Univ. of Maryland F. Benmokhtar, T. Horn Dept. of Phys. Southern Univ. at New Orleans M. Elaasar Phys. and Astro. Dept. California State Univ. Ed F. Gibson

3 Introduction p-shell nuclei : 6,7 Li, 10,11 B, 12 C, (H 2 O for calibration) ~ Fine structure ; core excited states etc. Baryon-baryon interaction in SU(3), charge symmetry breaking,  coupling in large isospin hypernuclei cluster structure etc. fp-shell nuclei : 40 Ca(PR08-002), 51 V, 52 Cr Beyond fp-shell : 89 Y ~ Single-particle potential Distinguishability of a  hyperon U 0 (r), m  *(r),.. E : Λ Hypernuclear Spectroscopy in the wide mass region

Layout of HKS-HES system in Hall-C HKS HES

5 Setup of the 3 rd generation experiment HES (e’ arm)HKS (K arm) Magnet ConfigurationQ-Q-D Central Momentum0.55~1.0 GeV/c1.2 GeV/c Momentum Acceptance±0.1 GeV/c±0.15 GeV/c Solid Angle10 msr8 msr Resolution (FWHM)2.0×10 -4 Newly constructed

E top 1 pass (GeV) E top 2pass (GeV) E e’ (GeV) E e at Hall-C (GeV) Acceptable Central Energy (GeV) HES ENGE Comparison of available beam energy between HKS+ENGE and HKS+HES (2 nd gen.) (3 rd gen.)

7 e’ from Bremss. Moeller ring e’ associates With virtual photon Background Signal e’ Beam （ 1.8GeV ） Targete’-arm rate 1 st Exp. (w/o tilt) 0.67  A 12 C, 22 mg/cm MHz 2 nd Exp. (w/ tilt) 30  A 12 C, 100 mg/cm 2 1 MHz How to avoid background electrons ~Tilt Method~ Backgrounds on e’ arm : e’ from Bremss. & Moeller →Tilt Method x’ y’ 2.5GeV Electron Beam Energy

8 Acceptance of HES Virtual Photon Energy 1.5 GeV Brems Moller Enge acceptance x’ y’ 2 nd gen. (E01-011) Enge 0.3 GeV/c Beam Energy 1.8 GeV HES acceptance 3 rd gen. (E05-115) HES 1.0 GeV/c Beam Energy 2.5 GeV ×10 10 times virtual photon tagging efficiency x’ y’

9 HES detectors e’ ED EDC1 EHODO1,2 Detector Specifications EDC1 (used in the 2 nd Exp.) Effective area100 W [cm] *12 H [cm] *32 T [cm] Layers10 (xx’, uu’, xx’, vv’, xx’) Layer distance7.5[cm] Cell Size0.5cm EDC2 (same type as HKS DC) ; Hampton Univ. Effective area105 W [cm] *30 H [cm] *3.5 T [cm] Layers6 (xx’, uu’, vv’) Drift Distance6.35mm EHODO1 ; Tohoku U.29 segments plastic scinti. EHODO2 ; Tohoku U.29 segments plastic scinti. Position DetectorsEDC1 （ Honeycomb type ） + EDC2 （ Planer type ） Trigger CountersEHODO1 + EHODO2 EDC2

10 Upgrade of HKS Detector package Renew boxes of Water Cherenkov （ Tohoku U.) –Improved light collection efficiency Add Lucite Cherenkov (Hampton U.) –Additional information on PID and TOF measurements Add bucking coil for Aerogel Cherenkov (Florida Int’l U.) –Cancel stray field of HKS dipole (~ 5 gauss) to recover gain of PMT LC Renew Bucking Coil Q-Q-D Add

11 Yield Estimation Target （ 100mg/cm 2 ） Yield for 100nb/sr [/hour] E （ 1.8GeV, 24  A ） E （ 2.5GeV, 30  A) 7 Li ( 15  A ) B C Ca―17 51 V―13 89 Y―7.5 about 5 times

12 Simulated spectrum of 51 V(e,e’K + ) 51  Ti HKS (8msr ) + HES ⊿ E = 300 keV [FWHM] Beam I = 30 [μA] V 100 [mg/cm 2 ] S/N=5 Expected Counts /100KeV/144h - B Λ ( MeV )

13 TOKIN (Sendai, Japan) CEBAF 2.5GeV Electron Beam Splitter 1.0GeV/c e’ 1.2GeV/c K + HESHES HKSHKS

14 Splitter Magnet 1.72 m

15 Q-Q-D Magnet EQ1 EQ2 ED EQ1 EQ m

16 Q-Q-D Magnet Tilt Version

17 Schedule Dec 2007HES departed from Japan Feb 2008HES arrives at Norfolk Mar 2008Test experiment of detectors at Tohoku Univ. (LNS) Apr 2008 Tohoku group begins stay at JLab By the end of 2008 Ready to install HES in Hall C

18 Summary HES magnets are on the way to JLab HES detectors are under construction Part of HKS detectors, WC and AC will be upgraded and LC will be added Yield is 5 times larger than the 2 nd generation exp. Will be ready to install HES by the end of 2008

Various targets E First Generation E Hall A Experiment E Second Generation E Third Generation PR Third Generation

20 HES-HKS momentum acceptance 51  Ti g.s   HKS HES

21 E Set Up