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Hypernuclei: A quick introduction Electroproduction of hypernuclei E94-107 experiment UPDATE Experimental equipment and setup Analysis results of 2004 run on 12 C and 9 Be Preliminary results of 2005 run on 16 O Conclusions Mauro Iodice – e94107 update – Hall A Collaboration Meeting, JLAB, Dec 6 2005
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A.Acha, H.Breuer, C.C.Chang, E.Cisbani, F.Cusanno, C.J.DeJager, R. De Leo, R.Feuerbach, S.Frullani, F.Garibaldi*, D.Higinbotham, M.Iodice, L.Lagamba, J.LeRose, P.Markowitz, S.Marrone, R.Michaels, Y.Qiang, B.Reitz, G.M.Urciuoli, B.Wojtsekhowski And the Hall A Collaboration J LAB H all A E 94107 C OLLABORATION Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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H YPERNUCLEI …what they are H ypernuclei are bound states of nucleons with a strange baryon (Lambda hyperon). A hypernucleus is a laboratory to study nucleon-hyperon interaction ( -N interaction). Extension of physics on N-N interaction to system with S0 Internal nuclear shell are not Pauli-blocked for hyperons. Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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H YPERNUCLEI and A STROPHYSICS S trange baryons may appear in neutral -stable matter through process like: The presence of strange baryons in neutron stars strongly affect their properties. Example: mass-central density relation for a non-rotating (left) and a rotating (right) star The effect strongly depends upon the poorly known interactions of strange baryons More data needed to constrain theoretical models. Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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H ypernuclei - historical background - experimental techniques To commemorate their discovery the above postcard was issued by the Polish Post in May 1993 1953 : discovery of first hypernucleus by Danysz and Pniewski while studying cosmic radiation with emulsion techniques 1962 : The first double Hypernucleus was discovered in a nuclear emulsion irradiated by a beam of K - mesons at CERN The first observation of a hypernucleus Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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1953 1970 : hypernuclear identification with visualizing techniques emulsions, bubble chambers 1970 Now : Spectrometers at accelerators: CERN (up to 1980) BNL : (K -, - ) and (K +, + ) production methods KEK : (K -, - ) and (K +, + ) production methods > 2000 : Stopped kaons at DA NE (FINUDA) : (K - stop, - ) > 2000 : The new electromagnetic way : HYPERNUCLEAR production with ELECTRON BEAM at JLAB Elementary reaction on neutron : e.g. Elementary reaction on proton : e.g. H ypernuclei - historical background - experimental techniques Production of MIRROR hypernuclei : I=0, q=0 n = p Spectroscopy of mirror hypernuclei reveal n p 0 mixing and N-N coupling
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Present status of Hypernuclear Spectroscopy O. Hashimoto and H. Tamura, Prog. Part. Nucl. Phys, in press. (e,eK + ) This exp. E94-107 Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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What do we learn from hypernuclear spectroscopy H ypernuclei and the -N interaction weak coupling model (parent nucleus) ( hyperon) (doublet state) S SNSN T (A-1) A SNSN, S, T Split by N spin dependent interaction Hypernuclear Fine Structure Low-lying levels of Hypernuclei Each of the 5 radial integral (V,, S, S N, T) can be phenomenologically determined from the low lying level structure of p-shell hypernuclei V Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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Electroproduction of hypernuclei by the reaction: E94-107 Experiment: High Resolution 1p Shell Hypernuclear Spectroscopy (spokespersons: F. Garibaldi, S. Frullani, J. Le Rose, P. Markowitz, T. Saito – Hall A Coll.) Hypernucleus K+K+ e e p A Z(e,eK) A (Z-1) HRS e at 6˚ HRS k at 6˚ e beam ~4 GeV Nuclear targets and resulting hypernuclei: 9 Be 9 Li (spin doublets, information on s-s term of -N interaction potential) 12 C 12 B (comparison with previous data: better understanding of results with hadron probes and E89-009 in Hall C at Jefferson Lab; clear identification of core excited states) 16 O 16 N (details of the hyper. spectrum also depends onsingle particle spin-orbit splitting ) Spin flip states p Production of mirror nuclei / n rich hypernuclei High energy resolution Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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D etection at very forward angle to obtain reasonable counting rate (increase photon flux) Septum magnets at 6° Excellent P article ID entification system for unambiguous kaon selection over a large background of p, RICH Accurate monitoring of many parameters over a long period of data taking : Beam spread (SLI, OTR) and absolute energy, spectrometers NMR, BPMs, … E xcellent energy resolution Best performance for beam and HRS+Septa with accurate optics calibrations Experimental requirements : 1. E/E : 2.5 x 10 -5 2. P/P (HRS + septum) ~ 10 -4 3. Straggling, energy loss… 600 keV Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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Last year e94107 experiment took data in two separate periods. Data have been collected on solid targets. The second part of the experiment took data in June 2005 in Hall A using the waterfall target January 2004 12 C target April 2004 12 C target and May 2004 9 Be June 2005 Waterfall target for hypernuclear state production on 16 O and (as a byproduct) on the elementary process on Hydrogen Data taking, Kinematics, Counting rates : E beam = 4.016 3.777 3.656 GeV P e = 1.80 1.56 1.44 GeV/c P k = 1.96 GeV/c e = K = 6° = E 2.2 GeV – Q 2 = 0.079 (GeV/c) 2 Beam current : 100 A Target thickness : ~100 mg/cm 2 Counting Rates ~ 0.1 – 10 counts/peak/hour Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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S EPTUM magnets in Hall A : new optics DB for the D+QQDQ system FWHM = 1.1x10 -4 FWHM = 2.2x10 -4 NEW DB 2005OLD DB 2004 Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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K AON Id Requirements physics case ProcessRates signalBound states (e,eK) 10 -4 – 10- 2 accidentals (e,e)(e, ) (e,e)(e,p) (e,e)(e,k) 100 0.1 Forward angles higher background of and p TOF and 2 Threshold Cherenkov NOT sufficient for unambiguous kaon identification RICH DETECTOR Signal Vs. Background Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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R ICH detector –C 6 F 14 /CsI proximity focusing RICH MIP Performances : N p.e. # of detected photons (p.e.) and (angular resolution) Cherenkov angle resolution Separation Power Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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R ich Performance key parameters: Angular resolution: N pe /p ratio: N pe for and p Cherenkov angle for Cherenkov average angle (rad) Nclusters Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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R ich – PID – Effect of Kaon selection: P K Coincidence Time selecting kaons on Aerogels and on RICH: AERO KAERO K && RICH K Pion rejection factor ~ 1000 Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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R ich – PID – Effect of Kaon selection: P K Coincidence Time selecting kaons on Aerogels and on RICH: AERO KAERO K && RICH K GREATLY improved AEROGEL performance! Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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Shell model excitation levels for 12 B dependence on the N potential - different set of potential params. x 0p x 0s 11 C energy spectrum J=1 -, 2 - doublet x 0s J=1 - J=2 - J=2 +, 3 + J=1/2 - E=~2 MeV J=3/2 - E=0.0 MeV J=3/2 - E=~5 MeV J=5/2 - E=~4.5 MeV x 0s 12 B energy spectrum J=1 - J=2 - J=2 +, 3 + J=1 - J=2 - J=2 +, 3 + YNG potentialCanonical Standard Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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Monte Carlo simulation of 12 B excitation-energy levels produced on 12 C target 12 C(e,eK) 12 B a c b d Absolute and relative positions of resolved levels a,b,c,d, may provide information on parameters of interaction potential and its terms (spin-spin, spin-orbit, tensor, …) Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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9 Be(e,eK) 9 Li a c d b Monte Carlo simulation of 9 Li excitation-energy levels Produced on 9 Be target Excitation-energy levels of 9 Li hypernucleus, especially from the first-doublet levels a and b, would provide important information on S and T terms of the N interaction. Separation of c and d doublets may provide information on the spin-orbit term S N Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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Theoretical model for 16 N excitation-energy on 16 O target The structure of underlying nucleus 15N is dominated by: (i)J=1/2-proton-hole state in 0p1/2 shell - ground state (ii)J=3/2- proton-hole state in 0p3/2 shell - Excited states at Ex = 6.32 MeV Details of the hypernuclear spectrum at Ex ~ 17-20 MeV depends not only on -N residual interaction but also on the single particle spin-orbit splitting (difference in energy of 0p3/2 and 0p1/2 states) Coupling of p1/2 and p3/2 16 O(e,eK) 16 N 15 N energy spectrum 16 N energy spectrum
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R esults from last year run on 12 C target Analysis of the reaction 12 C(e,eK) 12 B Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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R esults on 12 C target – Hypernuclear Spectrum of 12 B 12 C(e,eK) 12 B < 1 MeV FWHM Missing energy (MeV) g.s. Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005 As obtained with the old optics DB. The new one does not improve the resolution … still under analysis/investigation
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Aerogel Kaon selection RICH Kaon selection 12 C(e,eK) 12 B A nalysis on 12 B spectrum : Aerogel vs. RICH K-selection Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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A nalysis on 12 B spectrum : FIT to the data Gaussian fit systematically underestimate The peaks try with different shapes : Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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J LAB Hall A E94-107: preliminary comparison with theory for 12 B hypernucleus Missing energy (MeV) Counts / 200 keV 12 C(e,eK) 12 B Two theoretical curves (blue and red), two different model for the elementary K- production on proton. Same hypernuclear wave- function (by Miloslav Sotona). Red line: Bennhold-Mart (K MAID) Blue line: Sagay Saclay-Lyon (SLA). Curves are normalized on g.s. peak. The relative intensity of first excited-core peak at 2.6 MeV and strongly populated p-Lambda peak at 11 MeV would be better described by K MAID model than SLA. Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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J LAB Hall A E94-107: preliminary comparison with theory for 12 B hypernucleus Missing energy (MeV) Counts / 200 keV 12 C(e,eK) 12 B Two theoretical curves (blue and red), two different model for the elementary K- production on proton. Same hypernuclear wave- function (by Miloslav Sotona). Red line: Bennhold-Mart (K MAID) Blue line: Sagay Saclay-Lyon (SLA). Curves are normalized on g.s. peak. Theory = 5.4 nb/(GeV sr 2 ) …!!! Stat ~ 4.3 % Syst ~ 20 % g.s. CrossSection = 5.00 nb/(GeV sr 2 ) Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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A nalysis on 12 B spectrum : COMPARISON with models New comparison: inclusion of all predicted levels bring to a stronger disagreement for levels with in p-shell Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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H. Hotchi et al., Phys. Rev. C 64 (2001) 044302 E94-107 Hall A Experiment Vs. KEK-E369 12 C(e,eK) 12 B 12 C(,K + ) 12 C Statistical significance of core excited states: Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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E94-107 Hall A Experiment Vs. FINUDA (at Da ne) 12 C(e,eK) 12 B 12 C(K -, ) 12 C Statistical significance of core excited states: Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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E94-107 Hall A Experiment Vs. HallC E89-009 12 C(e,eK) 12 B Miyoshi et al., PRL 90 (2003) 232502. New analysis Statistical significance of core excited states: Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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E94-107 Hall A Experiment: status of 12 B data 12 C(e,eK) 12 B Statistical significance of core excited states: Energy resolution is ~ 900 keV with old optics database More than one year spent to improve the resolution Although the new database does a very good job for single arm elastics data: 1.1 10 -4 the expected resolution of less than 600 keV is not yet achieved some more check and tuning has to be done, …but : despite the fact that optimal resolution has not yet been obtained, the data are of extremely good quality … to be published soon Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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R esults from last year run on 9 Be target Analysis of the reaction 9 Be(e,eK) 9 Li (still preliminary) Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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Missing energy (MeV) Counts / 400 keV 9 Be(e,eK) 9 Li Aerogel Kaon selection RICH Kaon selection J LAB Hall A E-94107: P reliminary R esults on 9 Be target Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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Missing energy (MeV) Counts / 200 keV Red line: Bennhold-Mart (K MAID) Blue line: Sagay Saclay-Lyon (SLA) Curves are normalized on g.s. peak. J LAB Hall A E-94107: P reliminary R esults on 9 Be target Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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F irst R esults from current experiment on WATERFALL target Analysis of the reaction 16 O(e,eK) 16 N and 1 H(e,eK) (elementary reaction) Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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2005 E-94107: Running on waterfall target Be windows H 2 O foil Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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2005 E-94107: Preliminary spectra of missing energy 1 H (e,eK) 16 O(e,eK) 16 N Low counting levels above E thr. 16 O(e,eK) 16 N Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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A nalysis on 16 N spectrum : FIT to the data Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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15 N energy spectrum 16 N energy spectrum A nalysis on 16 N spectrum : COMPARISON with models High energy excited MULTIPLETS seems NOT WELL reproduced by the model. -interaction here is in p-state, poorly known…. Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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A nalysis on 16 N spectrum : COMPARISON with models …SHIFTING by hand the positions of these MULTIPLETS in the model, while mantaining the predicted strength, a VERY GOOD agreement with the data can be reached. Work is in progress for a deeper physics interpretation. Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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16 O(e,eK) 16 N E94-107 Hall A Experiment Vs. KEK-E336 16 O(,K + ) 16 O Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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16 O(e,eK) 16 N E94-107 Hall A Experiment Vs. -ray spectroscopy at BNL 16 O(K -, ) 16 O Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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I mportance of the elementary reaction 1 H(e,eK) at low Q 2 In K + photoproduction on proton there is a clear inconsistency of the experimental data (CLAS vs SAPHIR) at K cm < 40 deg. Electroproduction at very low Q 2 can clarify this inconsistency, which is also important for calculation for hypernuclear cross sections. 1 H (e,eK) K + photoproduction Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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C onclusions: Experiment E94-107 at Jefferson Lab: GOAL is to carry out a systematic study of light hypernuclei (shell-p). The experiment required important modifications on the Hall A apparatus. Good quality data on 12 C and 9 Be targets ( 12 B and 9 Li hypernuclei) have been taken last year New experimental equipments showed excellent performance. The RICH detector performed as expected and it is crucial in the kaon selection. On-going Analysis of data on 12 C target is showing new information on 12 B and interesting comparison with theory for 12 B and 9 Li. VERY Promising physics is coming out from new data on the waterfall target for 16 N hypernuclear spectroscopy - also for p(e,eK)X-Sect. measurement Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005
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