PR12-13-002A Study with High Precision on the Electro-production of the Lambda and Lambda Hypernuclei in the Full Mass Range
S.N.Nakamura
Tohoku University
Hall-A Meeting/JLab PAC40
14 June 2013
Nuclear ForceLots of NN scattering data
Nuclear StructureNormal/Exotic nuclei
Established Calculation Tech.Cluster ModelShell ModelMean Field
Hyperon ForceLimited YN/YY scattering data
Nuclear StructureHypernuclei
Baryon Interaction
QCD
Quark degree of freedomSUf(3) Symmetry
Lattice QCDModarn baryon Interaction models
S N Nakamura @ Tohoku Univ.
Objectives --- Hypernuclear Physics
Medium - Heavy hypernuclei
Light Hypernuclei (s,p shell)
A 1 20 50 200 1057
Elementary Process
Strangeness electro-production
CSB, LS coupling in large isospin hypernuclei
Hyperonization Softening of EOS ?
Single-particle potentialU0(r), mL*(r), VLNN, ...
Collective motion of nucleons Deformation of nuclei
Neutron/Hyperon star,Strangeness matter
Extend Nuclear Force to Baryon Interaction
Use L as a probe to see deep inside of nucleus
S N Nakamura @ Tohoku Univ.
History of Hypernuclear Study
1953 discovery of hypernucleus (emulsion with cosmic-ray, by Danysz and Pniewski)
1970s CERN, BNL Counter experiments with Kaon beam
1980s BNL-AGS, KEK-PS Counter experiments with K/p beam
1998- g-spectroscopy with Hyperball
2000~
(e,e’K+) spectroscopy @ JLab E89-009 (2000), E97-104 (2004),
E01-011 (2005), E05-115 (2009)
Z(e-,e’K+)L( -1) Z reaction
HKSHES
2011~ Decay p Spectroscopy at MAMI-C
DAFNE (stop K)
History of Hypernuclear Study
2011~ Pilot runs of decay p spectroscopy at MAMI-C
HKSHES
2000~
(e,e’K+) spectroscopy @ JLab E89-009 (2000), E97-104 (2004),
E01-011 (2005), E05-115 (2009)
Z(e-,e’K+)L( -1) Z reaction
Characteristics of (e,e’K) HY study Electromagnetic production
Convert Proton to Lambda : Mirror/iso-multiplet partners study
well studied HY by (p,K), (K,p)
Absolute energy calibration with L and S0 masses
p(e,e’K+) L ,S0
High quality primary beam
High energy resolution (< 1MeV)
Thin enriched target
Challenge of (e,e’K) HY Study Huge e’ Background due to
Bremsstrahlung and Mfller scattering
Signal/Noise, Detector
Less Hypernuclear Cross SectionCoincidence Measurement (e’, K+)
Limited Statistics
DC beam is necessary
High Quality Electron Beam is Essential !
What we have developed at JLabHigh Resolution, Large Solid Angle and Short Orbit Spectrometer (Hall-C)
HKS
RICH for good K ID (Hall-A) RICH
SC Septum for charge separation (Hall-A)
SC Septum
High Resolution Electron Spectrometer (Hall-C)
HES
JLab’s Hypernuclear Program To DateNucleus What Have We Learned?
H(e,e’K)L Very Forward, Small Q2
Elementary L Cross section is important. Phys. Rev. C81 (2010) 052201(R).
7Li(e,e’K+)7LHe First reliable observation of 7
LHe w/ good statistics, CSB of LN interactionPhys. Rev. Lett. 110 (2013) 012502.
9Be(e,e’K+)9LLi Theory doesn’t reproduce observed energies and strengths. To be published soon.
Preliminary result can be found in Nucl. Phys. A804 (2008) 116.Nucl. Phys. A835 (2019) 129.
10B(e,e’K+)10LBe CSB discussion with A=7, A=4 system.
Analysis is in progress.
12C(e,e’K+)12LB A reference nucleus.
Demonstrates high resolution
750 keV (FWHM)
16O(e,e’K+)16LN Study of mirror hypernuclei to 16
LO.
28Si(e,e’K+)28LAl First beyond p-shell hypernuclear spectroscopy with (e,e’K).
52Cr(e,e’K+)52LV First medium heavy hypernuclear study with (e,e’K).
Phys. Rev. Lett. 90 (2003) 232502.Phys. Rev. C73 (2006) 044607.
Phys. Rev. Lett 99 (2007) 052501.Nucl. Phys. A835 (2010) 129.
One of proposing program.
Phys. Rev. Lett. 103 (2009) 202501.Nucl. Phys. A835 (2010) 129.
Analysis in progress.
Preliminary result can be found in Nucl. Phys. A804 (2008) 125.
Analysis in progress.
Hypernuclear Chart
K40L K
44L K48
L
Sc48L
K40L
[ ]LN
L
Tl208L
H4L
MgL27
B12L
Hall-A setup vs. Hall-C setup
Hall-A (E94-107) Hall-C (E05-115) PR12-13-002New ExperimentIn Hall-A
Beam Energy 3.7 GeVLow Brems. e’ BG.
2.3 GeV 4.5 GeVLower Brems BG.
Virtual Photon E g = 2.3 GeV E g = 1.5 GeVLarger sL
E g = 1.5 GeVLarger sL
Charge Separation SC septumEasier calib.
SplitterLarger S.A.
SC + New SeptaEasier calib., Opt. SA
K Spectrometer HRS (2.0 GeV/c) HKS (1.2GeV/c)Larger S.A., Easier PID
HKS (1.2GeV/c)Larger S.A., Easier PID
e’ Spectrometer HRS (1.4 GeV/c)Higher momentum
HES (0.8 GeV/c)Low momentumHigh res., Short Orb.
HRS (3.0 GeV/c)
Decay p Spectroscopy
HES + ENGE(90-140 MeV/c)
Proposing Setup
K(HKS) x HRS (e’) + K(HKS) x {ENGE (p) + HRS (p)}
Expected Yields
>5 times more yield than E94-107Much better S/N than E05-115
Expected Mass Resolution
Calibration for independent K, e’ spectrometers.Established in E94-107.
Absolute missing mass calibration with ,L S0 massesEstablished in E05-115.
Proposing Programs1. Elementary , L S0
Reliable data 1H(e,e’K+) , L S0 in low Q2
2. Few-body 2D(e,e’K+) [LN] Exotic bound state, LN int. 4He(e,e’K+)4
L H LN CSB
3. Medium-heavy40,44,48Ca(e,e’K+) 40,44,48
LK L’s S.E., iso-spin 27Al(e,e’K+) 27
LMg Tri-axial deformation48Ti(e,e’K+) 48
LSc Level inv. due to L 4. Heavy
208Pb(e,e’K+) 208LTl L in heaviest nucleus
5. Decay pWeak decay of light hyper-fragments