Recent results from Recent results from the Hall C hypernuclear programthe Hall C hypernuclear program
- JLab E01-011 -
Osamu HashimotoOsamu HashimotoTohoku UniversityTohoku University
HYP2006Mainz, October 11-14, 2006
E01-011 hypernuclear E01-011 hypernuclear collaborationcollaboration
– Y. Fujii, O. Hashimoto (Spokesperson), D. Honda, M. Kaneta, F. Kato, D. Kawama, A. Matsumura, N. Maruyama ,T. Miyoshi, S.N. Nakamura (Spokesperson), H. Nomura, K.Nonaka ,A. Ohtani, Y. Okayasu, M. Sumihama, H. Tamura (Tohoku U)
– S. Kato (Yamagata U)– T. Takahashi, Y. Sato, H. Noumi (KEK)– O.K. Baker, M. Christy, L. Cole, P. Gueye, C. Keppel, L. Tang (Spokesperson),
L. Yuan (Hampton U)– B. Beckford, S. Gullon, P. Markowitz, J. Reinhold (Spokesperson), C. Vega (FlU)– Ed.V. Hungerford, K. Lan, N. Elhayari, N. Klantrains, Y. Li,S. Radeniya , Murad, V.
Rodrigues (Houston)– R. Carlini, R. Ent, H. Fenker, T. Horn, D. Mack, G. Smith, W. Vulcan, S.A. Wood, C.
Yan (JLab)– N. Simicevic, S. Wells (Louisiana Tech)– L. Gan (North Carolina, Wilmington)– A. Ahmidouch, S. Danagoulian, A. Gasparian (North Carolina A&T)– M. Elaasar (New Orleans)– R. Asaturyan, H. Mkrtchyan, A. Margaryan, S. Stepanyan, V. Tadevosyan
(Yerevan)– D. Androic, T. Petkovic, M. Planinic, M. Furic, T. Seva (Zagreb)– T. Angelescu (Bucharest)– V.P. Likhachev (Sao Paulo)– M. Ahmed (Duke)– B. Hu, Y. Song, C. Yang (Lanzhou)
1989 The first hypernuclear experiment in1989 The first hypernuclear experiment in Hall C, E89-009, approved 1994 Hypernuclear experiment in1994 Hypernuclear experiment in Hall A, E94-107, approved1995 JLab started physics experiments1995 JLab started physics experiments1997 Hall C 21997 Hall C 2ndnd generation experiment, E97-008, approved, later updated as E01-011 generation experiment, E97-008, approved, later updated as E01-0112000 2000 The first (e,e’K+) hypernuclear spectroscopy, E89-009, carried out2002-20032002-2003
High resolution kaon spectrometer (HKS) for the E01-011 experiment under constructiHigh resolution kaon spectrometer (HKS) for the E01-011 experiment under constructionon
20042004 Hypernuclear experiment in Hall A, E94-107, carried out20052005 Hypernuclear experiment in Hall A, E94-107, carried out The second generation experiment in Hall C, E01-011, carried out The 3rd generation hypernuclear experiment in Hall C, E05-115, approved
2006-20072006-2007 New electron spectrometer for the 3New electron spectrometer for the 3 rdrd generation experiment, E05-115, generation experiment, E05-115, under constructionunder construction
2008 The E05-115 experiment will be ready for beam in Hall C 2008 The E05-115 experiment will be ready for beam in Hall C ( Nue Nakamura’s Talk )
(e,e’K(e,e’K++) hypernuclear spectroscopy at ) hypernuclear spectroscopy at JLabJLab
Hypernuclear investigationHypernuclear investigation• Mean field aspects of nuclear matterMean field aspects of nuclear matter
– A baryon deep inside a nucleus A baryon deep inside a nucleus distinguishable as a baryon ?distinguishable as a baryon ?
• N interactionN interaction– Flavor SU(3) Flavor SU(3) – mixing or the three-body interactionmixing or the three-body interaction
• New form of nucleiNew form of nuclei
Spectroscopy in the wide mass rangeHigh resolution and High yield rate
Single particle statesSingle particle states
-> -> -nuclear potential-nuclear potential
hyperon in a heavier nucleushyperon in a heavier nucleus
Single-particle orbits in a nucleus
E140a at KEK
Hotchi et al., PRC 64 (2001) 044302 Hasegawa et. al., PRC 53 (1996)1210KEK E140a
• Skyrme HF (Yamamoto)• DDRH (Lenske)• Quark-meson coupling (Saito, Thomas)• ………
Y La PbSi
Hypernuclear Hypernuclear spectroscopyspectroscopy
Reaction spectroscopy -ray spectroscopy
• Resolution > 1.5 MeV with meson beams so far• Applicable to all hypernuclear states• Mass, cross sections, angular distributions, polarization….• Each reaction populates characteristic states
• Resolution as good as a few keV• Applicable to the states below nucleon emission thresholds• Angular distribution, lifetime, branching ratios…• Powerful for spin dependent interaction
Complimentary
Better resolution required Higher yield required
B=0 Hypernuclear production
(+,K + )
Stopped (K-,)
(e,e’K+)(,K + )
(p,K+ )
Inflight(K-,)
Hyp
ernu
clea
r C
ross
sec
tio n
Momentum transfer (MeV/c)
mb/sr
nb/sr
b/sr
0 500 1000
JLab
KEK, BNL
BNL, CERN (K-,-)
(+,K+)
(+,K+)
Expansion of hypernuclear chartExpansion of hypernuclear chartby the (e,e’Kby the (e,e’K++) reaction) reaction
Mirror symmetric hypernuclei
A: to be studied by the (e,e’K+) reaction
( ppnp 57(2006) )
K+ detection At very forward angle (~ 0 degrees) Maximum hypernuclear production cross section
e’ detection = tag virtual photon energy and emission angle At extremely forward angles Advantage : Large virtual photon flux Disadvantage : Huge backgrounds from Bremsstrahlung
Kinematics of the (e,e’KKinematics of the (e,e’K++) reaction in ) reaction in Hall C Hall C
pe=0.3GeV/c e’
K+
pK=1.2 GeV/c
Ee=1.8 GeVe- Beam
Target nucleus
E=1.5 GeV21 1.2 1.4 1.6 1.8
σto
tal(
b)
1.0
2.0
Eγ(GeV)
p(,K+) Total cross section
Phys. Lett. B 445, 20 (1998)M. Q. Tran et al.
Kaon Angular Distribution
Angle (deg)
d/d
(
nb/s
r)
Electron Angular Distribution
Angular distributions of Angular distributions of scattered electrons and kaonsscattered electrons and kaons
Sotona
The first (e,e’KThe first (e,e’K++) spectroscopy experiment) spectroscopy experiment(JLab E89-009)(JLab E89-009)
Ee = 1.7,1.8 GeV = E = 1.5 GeVpK = 1.2 GeVe = 0 degreesk = 0-7 degrees
• Electron spectrometer --- Enge split pole• Kaon Spectrometer --- SOS (Short Orbit Spectrometer)• Splitter magnet• 0 degree tagging geometry
SOS
152 nb/sr
1212B spectrum of E89-009B spectrum of E89-009
Ground state doublet
B = 11.4 ± 0.5 MeV
Cross section 140±17(stat) ±18(sys) nb/sr
Motoba’s calculation
Binding energy
Emulsion data B = 11.37 MeV
d/
d
nb
/sr/
0.3
MeV
-B(MeV)
-15 0 5 10 15-5-10
(2+,3+)(1-,2-)
(1-,0-)
(2-,1-)
40
50
60
70
80
90
~ 750 keV(FWHM)
292 hrs0.66 A
T. Miyoshi et al., Phy. Rev. Lett. 90, 232502(2003)
J cross section 1-
2-
What limited the E89-009 What limited the E89-009 experiment ?experiment ?
• Hypernuclear yield rateHypernuclear yield rate– High accidental background rate due to Brems High accidental background rate due to Brems
electrons limited luminosityelectrons limited luminosity
– Kaon solid angle limited detection efficiencyKaon solid angle limited detection efficiency
• Energy resolutionEnergy resolution– The kaon arm limited hypernuclear mass resolutionThe kaon arm limited hypernuclear mass resolution
(1) A high-resolution large-solid-angle kaon spectrometer (HKS)
(2) New experimental configuration “Tilt method”
Maximum momentum 1.2 GeV/cDispersion 4.7 cm/%Momentum resolution 2 x 10-4(FWHM)Solid angle 30 msr w/o splitter 16 msr w splitterMomentum acceptance 12.5 %
The HKS spectrometer system for E01-The HKS spectrometer system for E01-011011
(2) Tilt method for the electron arm
(1) High resolution Kaon Spectrometer (HKS)
K+
e’
E01-011 setup in Hall E01-011 setup in Hall CC
ENGE
HKS
Electron beam
To beam dump
From upstream
Splitter
Electron beam
e’
K+
To beam dump
Kinematical regions of electrons and Kinematical regions of electrons and kaonskaons
12Bgr band
Real data
HKS detectorsHKS detectors
HKS exit
p,K+,+,e+
Time of flight w/ cherenkov Time of flight w/ cherenkov cutcut
p K
p K
tof – K
After cherenkov cut
Tilt methodTilt method
The electron spectrometer (ENGE) vertically tilted by 8 degree
e’8 degree
--- Normal to the dispersive plane of the splitter magnet ---
Higher luminosity Higher hadron rates
Beam currents, singles rates & trigger Beam currents, singles rates & trigger ratesrates
TargetTarget
TargetTargetThicknesThicknes
ss(mg/(mg/cmcm22))
Beam cBeam currenturrent((A)A)
Hadron Hadron singles rate singles rate
(kHz)(kHz)
electron electron singles rate singles rate
(kHz)(kHz)
COIN COIN Trigger Trigger
rate rate (kHz)(kHz)
CHCH22 5mm5mm 1.51.5 3.43.4 590590 0.0880.088
77LiLi 190190 2525 1111 12001200 0.850.85
1212CC 100100 2424 9.59.5 980980 0.2900.290
2828SiSi 6565 1313 7.07.0 1040 1040 0.3770.377
“Tilt method” works !!
E01-011E01-011
Expected yield comparison of E01-011 and Expected yield comparison of E01-011 and E89-009E89-009
ItemItem E01-011E01-011(2(2ndnd generation) generation)
E89-009E89-009(1(1stst
generation)generation)
Gain Gain factorfactor
Virtual photon flux per Virtual photon flux per electron(x10electron(x10-4-4))
0.20.2 44 0.050.05
Target Target thickness(mg/cmthickness(mg/cm22))
100100 2222 4.54.5
Kaon survival rateKaon survival rate 0.350.35 0.40.4 0.880.88
Solid angle of K arm Solid angle of K arm (msr)(msr) 1616 55 3.23.2
Beam current (Beam current (A)A) 2424 0.660.66 3636
Estimated yield Estimated yield ((1212
BBgrgr:counts/h):counts/h)2020
(expected)(expected)
0.90.9(measured(measured
))2323
p(e,e’Kp(e,e’K++))0 0 reactions on CH2 reactions on CH2 targetstargets
12C(e,e’K+) quasi-free
Accidental
E89-009 E01-011
0
450 mg/cm2, 1.5 A, ~ 70 hours8.8 mg/cm2, 0.5 or 1.0 A, 183 hours
1.43 MeV (FWHM)
1.47 MeV (FWHM)
1212CC (e,e’K(e,e’K++))1212B spectraB spectra
Prelim
inary
Hypernuclear excitation spectrum
d/
d
nb
/sr/
0.3
MeV
-B(MeV)
E01-011E89-009
~ 800 keV
Co
un
ts (
0.2
5 M
eV/b
in)
s p292hrs 0.66A
AccidentalsAccidentals
~ 90 hrs 30 A
T. Miyoshi et al., Phy. Rev. Lett. 90, 232502(2003)
Sotona,Motoba 1212C (C (,K,K++))1212CC
B = 10.8 MeV B = -0.2 MeV
12Cg.s yield rate
~20 /hr(1 g/cm2 target)
KEK-E336 SKS
Co
un
ts (
0.2
Me
V/b
in)
Reaction spectra on a Reaction spectra on a 1212C targetC target
Co
un
ts (
0.25
MeV
/bin
)
s p
JLAB – JLAB – HKSHKS
~ 90 hrs ~ 90 hrs w/ 30w/ 30A A
PreliminaryPreliminary
AccidentalsAccidentals
B (MeV)
Core excited
12Bg.s yield rate
~8 /hr (0.1 g/cm2 target)
B(s) = 11.5 MeV B(p) = 1.0 MeV
1212C (e,e’KC (e,e’K++))1212BB
(Preliminary)
Motoba with full (sd)n wave function
AccidentalsAccidentalsCo
un
ts (
0.2
5 M
eV/b
in)
PreliminaryPreliminary
s
p 28Si(e,e’K+)28Al
reaction
B (MeV)
750 keV(FWHM)
B (s)= 18.1 MeV
B (p)= 7.4 MeV
Reaction spectra on a Reaction spectra on a 2828Si targetSi target
( Preliminary )
28Si(,K+)28Si reaction
B (s)= 16.6 MeV
B (p)= 7.0 MeV
KEK E140a SKS
28Si enriched target used
AccidentalsAccidentals
B (MeV)
Co
un
ts (
0.4
MeV
/bin
)
77Li(e,e’KLi(e,e’K++))77He reactionHe reaction
PreliminaryPreliminary 30 hrs 3030 hrs 30AA
s
E. Hiyama, et al., PRC53 2078 (1996)
Sotona
B = 5.4 MeV ( Preliminary )
Reaction spectrum on a Reaction spectrum on a 77Li targetLi target
960 keV (FWHM)
Evolution of (e,e’KEvolution of (e,e’K++) spectroscopy at JLab) spectroscopy at JLab
E89-009E89-009 E94-107E94-107 E01-011E01-011 E05-115E05-115
ConfigurationConfigurationSOS+ENGESOS+ENGE
+Splitter+SplitterHRS+HRSHRS+HRS
+Septum+Septum
HKSHKS+ENG+ENGEE
+Splitter+Splitter
HKSHKS+HES+HES
++New New splittersplitter
Beam intensity (Beam intensity (A) on A) on 1212CC 0.660.66 100100 2424 3030
thickness (mg/cmthickness (mg/cm22)) 2222 100100 100100 100100
Hypernuclear yieldHypernuclear yield
(12(12BBgr :gr : /hr) /hr) 0.90.9 44 8~(20)8~(20) (~40)(~40)
Resolution (keV)Resolution (keV) 750-900750-900700~800700~800(400 keV)(400 keV)
700~800700~800
(3-400)(3-400)(3-400)(3-400)
Beam energy (GeV)Beam energy (GeV) 1.7-1.81.7-1.8 44 1.81.8 2.0 - 2.5*2.0 - 2.5*
ppKK (central : GeV)(central : GeV) 1.21.2 1.91.9 1.21.2 1.21.2
ppee (central: GeV )(central: GeV ) 0.30.3 2.22.2 0.30.3 0.6 – 1.00.6 – 1.0
KK (degree)(degree) 0-70-7 66 1-131-13 1-131-13
e e (degree)(degree) 00 66 4.54.5 2 - 102 - 10
( ) expected
2000 2004-2005 2005 2008?
SummarySummary• Precision hypernuclear spectroscopy by the (e,e’KPrecision hypernuclear spectroscopy by the (e,e’K++) reacti) reacti
on plays an essential role in the investigation of hadronic on plays an essential role in the investigation of hadronic may-body systems that contain “strangeness”.may-body systems that contain “strangeness”.
• The 2nd generation experiment in Hall C, JLab E01-011, The 2nd generation experiment in Hall C, JLab E01-011, has been performed in 2005, installing the new kaon spehas been performed in 2005, installing the new kaon spectrometer (HKS) and adopting so-called “tilt” geometry for ctrometer (HKS) and adopting so-called “tilt” geometry for the electron spectrometer. the electron spectrometer.
• Resolution as good as ~700 keV(FWHM) and yield rate of Resolution as good as ~700 keV(FWHM) and yield rate of 7-8 counts/hr for the 7-8 counts/hr for the 1212
B ground state doublet were realB ground state doublet were realized.ized.
• Preliminary spectra for a Preliminary spectra for a 2828Si target as well as those for Si target as well as those for 11
22C and C and 77Li targets are presented, and compared with calcLi targets are presented, and compared with calculated spectra and (ulated spectra and (++,K,K++) reaction spectra. ) reaction spectra.