JLab Hypernuclear Workshop 27 th May 2014 Satoshi N Nakamura, Tohoku University HKS HES Results from Hall-C
Nuclear Force Lots of NN scattering data Nuclear Structure Normal/Exotic nuclei Established Calculation Tech. Cluster Model Shell Model Mean Field Hyperon Force Limited YN/YY scattering data Nuclear Structure Hypernuclei Baryon Interaction QCD Quark degree of freedom SU f (3) Symmetry Lattice QCD Modern baryon Interaction models
EM Interaction p to primary e beam Characteristics of hypernuclear study by (e,e’K) reaction Electron BG Small C.S. Coin. measure High Quality Beam Sophisticated Detectors
Three generation experiments at Hall-C E (2000) : Existing spectrometers, SOS + Enge Proof of Principle E (2005) : Construction of HKS, Tilt Method , 0, 7 He, 12 B, 28 Al Light Hypernuclei E (2009) : HES, new Beamline, Splitter , 0, 7 He, 12 B, 52 V Light to medium-heavy Hypernuclei
Proof of Principle (E89-009, HNSS) Demonstrated that the (e,e’K) hypernuclear spectroscopy is possible! 12 C(e,e’K + ) 12 B PRL 90 (2003) , PRC 73 (2006) Good energy resolution <900 keV (FWHM) ss pp
Improvement of the E experiment Resolution & acceptance are limited BG from Bremsstrahlung (200 MHz for e’ arm) Tilt Method N ew Spectrometer High resolution Kaon Spectrometer (HKS) The 2 nd Generation Experiment was approved by Jlab PAC19 E (Spokesmen: Hashimoto, Tang, Reinhold, Nakamura) Zero degree e’ measure
2005 E (Hall C) First step to beyond p-shell hypernuclei ( 28 Al, 12 B, 7 He) Beam: 30 μA, 1.8GeV HKS: Δp/p=2 x [FWHM] Solid angle 16msr(w/ splitter) ENGE HKS Splitter Electron beam To beam dump Target Two Major Improvements New HKS Tilt Method
n pp n np 0.35 MeV 0.24 MeV Coulomb effect is small. Charge Symmetry Breaking Charge Symmetry Breaking Effect of N interaction 4H4H 4 He cf) B( 3 H)-B( 3 He)- B c = = 71 keV
B of light hypermultiplets Hiyama et al. PRC80.(2009) PTP 128 (2012) 105. n np p np p n 7 Li* p 7 Be p n n 7 He 4H4H 4 He 10 B n 10 Be p Experimental B CSB NO reliable B 67 events 98 events 167 events 15 events 3 event 10 events Exp. Data : Emulsion
7 Li(e,e’K + ) 7 He First reliable observation of 7 He w/ good statistics PRL 110 (2013) M.Juric et al. NP B52 (1973) 1 FWHM 0.63 MeV Last missing information of A=7 hypernuclear iso-triplet E01-011(HKS) 90 counts E05-115(HKS-HES) >500 counts
2009 E Wide mass range hypernuclear spectroscopy ( 7 He~ 52 V ) HKS+ new HES spectrometers Tilt method suppress electron background by > GeV e - γ e-e- 1.2 GeV /c K GeV e ’
12 C( +,K + ) 12 BNL-AGS,KEK-PS 12 C(e,e’K + ) 12 JLab Hall C Resolution ~ 2MeV Resolution ~ 1.6 MeV Resolution ~ 0.5MeV Absolute binding energy Excitation energy (gs energy from emulsion) JLab E C(e,e’K + ) 12 B Paper is going to submit soon.
7 He spectrum of E T. Gogami, Doctor Thesis (Tohoku U.) 6 He : 2n halo E.Hiyama et al. PRC 80, (2009)
7 He spectrum of E T. Gogami, Doctor Thesis (Tohoku U.) Assumed CSB potential may be too naïve Further study on A=4 hypernuclear systems
10 B(e,e’K + ) 10 Λ Be + T. Gogami, Doctor Thesis (Tohoku U.)
Comparison of 10 Be and 10 B CSB off : MeV CSB on : MeV Experiments Theoretical calc.
Theory 52 Cr(e,e’K + ) 52 Λ V
12 C : Ref. for all ( ,K) data Power of Absolute E Calib.
Measured hypernuclei & expected A dependence E Calculation from Y.Yamamoto ss pp dd ff gg
Present Status of Hypernuclear Spectroscopy Updated from: O. Hashimoto and H. Tamura, Prog. Part. Nucl. Phys. 57 (2006) V
Summary Three generations of experiment at JLab Hall-C two major magnetic spectrometers (HKS, HES) novel techniques in the last decade. E : Feasibility of (e,e’K) hypernuclear spectroscopy E : 7 He, CSB and first beyond p-shell 28 Al E : 7 He, 10 Be : CSB and detailed spectroscopy 12 B, best resolution & absolute B calibration 52 V: First medium-heavy hypernucleus (e,e’K) HY spectroscopy is now established at JLab and JLab is unique. Next Step: Detailed structures for lighter targets Major shell structures for heavier targets