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High Resolution Hypernuclear Spectroscopy experiment e94-107 Update

High Resolution Hypernuclear Spectroscopy experiment e94-107 Update. 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

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High Resolution Hypernuclear Spectroscopy experiment e94-107 Update

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  1. High Resolution Hypernuclear Spectroscopy experiment e94-107 Update • Hypernuclei: A quick introduction • Electroproduction of hypernuclei • E94-107 experiment UPDATE • Experimental equipment and setup • Analysis results of 2004 run on 12C and 9Be • Preliminary results of 2005 run on 16O • Conclusions Mauro Iodice – e94107 update – Hall A Collaboration Meeting, JLAB, Dec 6 2005

  2. JLABHall AE94107 COLLABORATION • 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 High Resolution Hypernuclear Spectroscopy experiment e94-107 Update Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  3. HYPERNUCLEI …what they are • Hypernuclei are bound states of nucleons with a strange baryon (Lambda hyperon). A hypernucleus is a “laboratory” to study nucleon-hyperon interaction (L-N interaction). • Extension of physics on N-N interaction to system with S0 • Internal nuclear shell are not • Pauli-blocked for hyperons. Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  4. HYPERNUCLEI and ASTROPHYSICS • Strange baryons may appear in neutral b-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

  5. Hypernuclei - historical background - experimental techniques 1953 : discovery of first hypernucleus by Danysz and Pniewski while studying cosmic radiation with emulsion techniques To commemorate their discovery the above postcard was issued by the Polish Post in May 1993 1962 : The first double LL 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

  6. Production of MIRROR hypernuclei L: I=0, q=0  Ln = Lp Spectroscopy of mirror hypernuclei reveal Ln ≠ Lp  LS0 mixing and LN-SN coupling Hypernuclei - historical background - experimental techniques 1953 1970 : hypernuclear identification with visualizing techniques emulsions, bubble chambers Elementary reaction on neutron : 1970 Now : Spectrometers at accelerators: CERN (up to 1980) BNL : (K-, p-) and (K+, p+) production methods KEK : (K-, p-) and (K+, p+) production methods e.g. > 2000 : Stopped kaons at DAFNE (FINUDA) : (K-stop, p-) Elementary reaction on proton : > 2000 : The new electromagnetic way : HYPERNUCLEAR production with ELECTRON BEAM at JLAB e.g.

  7. This exp. E94-107 (e,e’K+) Present status of LHypernuclear Spectroscopy O. Hashimoto and H. Tamura, Prog. Part. Nucl. Phys, in press. Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  8. What do we learn from hypernuclear spectroscopy Hypernucleiand theL-Ninteraction “weak coupling model” (parent nucleus) (L hyperon) (doublet state) V SL SN T D Each of the 5 radial integral (V, D, SL , SN, T) can be phenomenologically determined from the low lying level structure of p-shell hypernuclei Low-lying levels of L Hypernuclei Hypernuclear Fine Structure SN Split by LN spin dependent interaction (A-1) D AL , SL , T Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  9. AZ(e,e’K)A(Z-1)L HRSeat 6˚ e’ e K+ e beam ~4 GeV p HRSkat 6˚ L Hypernucleus E94-107Experiment: “High Resolution 1p Shell Hypernuclear Spectroscopy” (spokespersons: F. Garibaldi, S. Frullani, J. Le Rose, P. Markowitz, T. Saito – Hall A Coll.) Electroproduction of hypernuclei by the reaction: • Spin flip states • pLProduction of mirror nuclei / n rich hypernuclei • High energy resolution • Nuclear targets and resulting hypernuclei: • 9Be  9LiL (spin doublets, information on s-s term of L-N interaction potential) • 12C  12BL (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) • 16O  16NL(details of the hyper. spectrum also depends on Lsingle particle spin-orbit splitting ) Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  10. Experimental requirements : • Detection at very forward angle to obtain reasonable counting rate (increase photon flux)  Septum magnets at 6° • Excellent ParticleIDentification system for unambiguous kaon selection over a large background of p, p RICH • Accurate monitoring of many parameters over a long period of data taking : Beam spread (SLI, OTR) and absolute energy, spectrometers NMR, BPMs, … • Excellent energy resolution  Best performance for beam and HRS+Septa with accurate optics calibrations 1.DE/E : 2.5 x 10-5 2. DP/P (HRS + septum) ~ 10-4 3. Straggling, energy loss… ≤ 600 keV Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  11. Data taking,Kinematics, Counting rates : • 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 12C target • April 2004 12C target and May 2004 9Be • June 2005 Waterfall target for hypernuclear state production on 16O and • (as a byproduct) on the elementary process on Hydrogen • Ebeam = 4.016 — 3.777 — 3.656 GeV • Pe= 1.80 — 1.56 — 1.44 GeV/c • Pk= 1.96 GeV/c • qe = qK = 6° • = Eg 2.2 GeV – Q2 = 0.079 (GeV/c)2 Beam current : 100 mA Target thickness : ~100 mg/cm2 Counting Rates ~0.1 – 10 counts/peak/hour Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  12. SEPTUM magnets in Hall A: new optics DB for the D+QQDQ system OLD DB “2004” NEW DB “2005” FWHM = 1.1x10-4 FWHM = 2.2x10-4 Thanks to Doug and co-workers Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  13. KAON Id Requirements physics case Signal Vs. Background Monte Carlo • Forward angles  higher background of p and p • TOF and 2 Threshold Cherenkov NOT sufficient for unambiguous kaon identification • RICH DETECTOR Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  14. RICH detector –C6F14/CsI proximity focusing RICH “MIP” Cherenkov angle resolution Separation Power Performances: Np.e. # of detected photons (p.e.) and sq (angular resolution) Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  15. Rich Performance ‘key parameters’: Npe for p and p Cherenkov angle for p Nclusters Npep/p ratio: Cherenkov average angle (rad) Angular resolution: Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  16. Rich – PID – Effect of ‘Kaon selection’: Coincidence Time selecting kaons on Aerogels and on RICH: AERO K AERO K && RICH K 2004 p P K Pion rejection factor ~ 1000 Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  17. Rich – PID – Effect of ‘Kaon selection’: Coincidence Time selecting kaons on Aerogels and on RICH: AERO K AERO K && RICH K 2005 K P GREATLY improved AEROGEL performance! p Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  18. Shell model excitation levels for 12BL dependence on the LN potential - different set of potential params. 12BL energy spectrum 11C energy spectrum J=2+, 3+ J=2+, 3+ J=2+, 3+ x 0pL J=2- J=2- J=2- x 0sL J=3/2- E=~5 MeV J=5/2- E=~4.5 MeV J=1- J=1- x 0sL J=1/2- E=~2 MeV J=1- J=1-, 2- doublet x 0sL J=3/2- E=0.0 MeV YNG potential “Canonical” “Standard” Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  19. Monte Carlo simulation of 12BL excitation-energy levels produced on 12C target Monte Carlo 12C(e,e’K)12BL d a c b Absolute and relative positions of “resolved” levels a,b,c,d, may provide information on parameters of L-N interaction potential and its terms (spin-spin, spin-orbit, tensor, …) Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  20. Monte Carlo simulation of 9LiL excitation-energy levels Produced on 9Be target Excitation-energy levels of 9LiL hypernucleus, especially from the first-doublet levels a and b, would provide important information on D, SL and T terms of the L-N interaction. Separation of c and d doublets may provide information on the spin-orbit term SN Monte Carlo 9Be(e,e’K)9LiL c d b a Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  21. 15N energy spectrum 16NL energy spectrum Coupling of Lp1/2 and Lp3/2 Theoretical model for 16NL excitation-energy on 16O target The structure of underlying nucleus 15N is dominated by: J=1/2-proton-hole state in 0p1/2 shell - ground state 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 L-N residual interaction but also on the L single particle spin-orbit splitting (difference in energy of 0p3/2 and 0p1/2 L states) 16O(e,e’K)16NL

  22. Results from last year run on 12C target Analysis of the reaction 12C(e,e’K)12BL Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  23. Results on 12C target – Hypernuclear Spectrum of 12BL Missing energy (MeV) 12C(e,e’K)12BL g.s. < 1 MeV FWHM As obtained with the old optics DB. The new one does not improve the resolution … still under analysis/investigation Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  24. Analysis on12BLspectrum : Aerogel vs. RICH K-selection 12C(e,e’K)12BL Aerogel Kaon selection RICH Kaon selection Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  25. Gaussian fit systematically underestimate The peaks  try with different shapes : Analysis on12BLspectrum : FIT to the data Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  26. JLAB Hall AE94-107: preliminary comparison with theory for 12BL hypernucleus 12C(e,e’K)12BL Two theoretical curves (blue and red),two different model for the elementary K-L 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. Counts / 200 keV Missing energy (MeV) 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

  27. JLAB Hall AE94-107: preliminary comparison with theory for 12BL hypernucleus g.s. CrossSection = 5.00 nb/(GeV sr2 ) Stat ~ 4.3 % Syst ~ 20 % Theory = 5.4 nb/(GeV sr2 ) …!!! 12C(e,e’K)12BL Two theoretical curves (blue and red),two different model for the elementary K-L 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. Counts / 200 keV Missing energy (MeV) Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  28. Analysis on12BLspectrum : COMPARISON with models New comparison: inclusion of ”all” predicted levels bring to a stronger disagreement for levels with L in p-shell Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  29. H. Hotchi et al., Phys. Rev. C 64 (2001) 044302 E94-107 Hall A Experiment Vs. KEK-E369 12C(e,e’K)12BL 12C(p+,K+)12CL Statistical significance of core excited states: Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  30. E94-107 Hall A Experiment Vs. FINUDA (at DaFne) 12C(e,e’K)12BL 12C(K-, p-)12CL Statistical significance of core excited states: Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  31. New analysis E94-107 Hall A Experiment Vs. HallC E89-009 12C(e,e’K)12BL 12C(e,e’K)12BL Miyoshi et al., PRL 90 (2003) 232502. Statistical significance of core excited states: Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  32. E94-107 Hall A Experiment: status of 12BL data 12C(e,e’K)12BL • 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 10-4the 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 Statistical significance of core excited states: Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  33. Results from last year run on 9Be target Analysis of the reaction 9Be(e,e’K)9LiL (still preliminary) Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  34. JLAB Hall AE-94107: PreliminaryResults on 9Be target 9Be(e,e’K)9LiL Counts / 400 keV Aerogel Kaon selection RICH Kaon selection Missing energy (MeV) Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  35. JLAB Hall AE-94107: PreliminaryResults on 9Be target Red line: Bennhold-Mart (K MAID) Blue line: Sagay Saclay-Lyon (SLA) Curves are normalized on g.s. peak. Counts / 200 keV Missing energy (MeV) Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  36. First Results from current experiment on WATERFALL target Analysis of the reaction 16O(e,e’K)16NL and 1H(e,e’K)L (elementary reaction) Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  37. 2005E-94107: Running on waterfall target H2O “foil” Be windows H2O “foil” Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  38. 16O(e,e’K)16NL Low counting levels above Ethr. 16O(e,e’K)16NL 2005E-94107: Preliminary spectra of missing energy 1H(e,e’K)L 16O(e,e’K)16NL Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  39. Analysis on16NLspectrum : FIT to the data Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  40. 16NL energy spectrum 15N energy spectrum Analysis on16NLspectrum : COMPARISON with models High energy excited MULTIPLETS seems NOT WELL reproduced by the model. L-interaction here is in p-state, poorly known…. Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  41. Analysis on16NLspectrum : 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

  42. E94-107 Hall A Experiment Vs. KEK-E336 16O(e,e’K)16NL 16O(p+,K+)16OL Very Preliminary Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  43. E94-107 Hall A Experiment Vs. g-ray spectroscopy at BNL 16O(e,e’K)16NL 16O(K-, p- g) 16OL Very Preliminary Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  44. Importance of theelementary reaction1H(e,e’K)L at low Q2 K+L photoproduction 1H(e,e’K)L In K+L photoproduction on proton there is a clear inconsistency of the experimental data (CLAS vs SAPHIR) at QKcm < 40 deg. Electroproduction at very low Q2 can clarify this inconsistency, which is also important for calculation for hypernuclear cross sections. Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

  45. Conclusions: • 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 12C and 9Be targets (12BL and 9LiL 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 12Ctargetis showing new information on 12BL and interesting comparison with theory for 12BL and 9LiL. • VERY Promising physics is coming out from new data on the waterfall target for 16NL hypernuclear spectroscopy - also for p(e,e’K)L X-Sect. measurement Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, Dec 6 2005

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