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