Hypernuclei,  – N interaction  Electroproduction of hypernuclei E experiment UPDATE  Experimental equipment and setup Kaon identification  RICH detector vs 2005 Analysis results of 2004 run Preliminary results of 2005 current data taking Conclusions Mauro Iodice – e94107 update – Hall A Collaboration Meeting, JLAB, June

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 J LAB H all A E C OLLABORATION Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, June

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 S0 Internal nuclear shell are not Pauli-blocked for hyperons. Experimental goals : Spectroscopy – Excitation Energy – doublet splitting Information on  -N interaction Hypernuclei Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, June

L ast year e94107 experiment has taken data in two separate period. Data have been collected on solid targets. The second part of the experiment is currently running in Hall A using the waterfall target January C target April C target and May Be June 2005 W aterfall target for hypernuclear state production on 16 O Data taking Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, June

“weak coupling model” (parent nucleus) (  hyperon) (doublet state)  N interaction potential: V  N = V o (r)V central + V  (r)  N ·    (spin-spin) + Vso(r)  N  ·     (spin-orbit) + Vso(r)  N  ·  N   N  (spin-orbit) + V T (r) S 12 T tensor 9 Be  9 Li  excitation energy Hypernuclei and  -N interaction 9 Be  9 Li  Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, June

Electroproduction of Hypernuclei e p K+K+ e’   * N … N nucleus Hypernucleus p beam Scattered electron Detected by HRS e Kaon detected by HRS k  N … N High luminosity, high duty cycle, excellent beam energy spread Better energy resolution than hadronic induced reactions, BUT smaller cross section Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, June

Electroproduction of hypernuclei by the reaction: Nuclear targets and resulting hypernuclei:  7 Li  7 He  (neutron excess)  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 E in Hall C at Jefferson Lab)  16 O  16 N  (details of the hypernuclear spectrum also depends on  single particle spin-orbit splitting ) Experimental requirements: 1.Excellent Energy Resolution (Best performance for Beam and HRS) 2.Detection at very forward angles (6° to obtain reasonably high counting rates  septum magnets ) 3.Excellent Particle Identification system (PID) for unambiguous kaon selection  RICH E Experiment: “High Resolution 1p Shell Hypernuclear Spectroscopy” (spokespersons: F. Garibaldi, S. Frullani, J. Le Rose, P. Markowitz, T. Saito – Hall A Coll.) Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, June

S EPTUM magnets in Hall A (Doug’s talk) FWHM = 1.1x10 -4  =20x20 mr 2 Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, June

K inematics, C ounting rates E beam = — — 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 = (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, June

H adron identification using Aerogel Threshold Cherenkov detectors p k All events  AERO1 n=1.015 AERO2 n=1.055 p k  p h = 1.7 : 2.5 GeV/c Protons = A1A2 Pions = A1A2 Kaons = A1A2 Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, June

K AON Id Requirements physics case ProcessRates signalBound states (e,e’K) – accidentals (e,e’)(e,  ) (e,e’)(e,p) (e,e’)(e,k) 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, June

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, June

The R ICH detector at Jefferson Lab Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, June

RICH photocathode installation Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, June

UV lamp The evaporator system Quantum Efficiency measurement system Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, June

R ich Performances ‘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, June

R ich – PID – Effect of ‘Kaon selection’:  P K Coincidence Time selecting kaons on Aerogels and on RICH: AERO KAERO K && RICH K Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, June Pion rejection factor ~ 1000

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, June

Monte Carlo simulation of 12 B  excitation-energy levels produced on 12 C target 12 C(e,e’K) 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, June

9 Be(e,e’K) 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, June

Theoretical model for 16 N  excitation-energy on 16 O target The structure of underlying nucleus15N 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 ~ 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,e’K) 16 N  15 N energy spectrum 16 N  energy spectrum

R esults from last year run on 12 C target Analysis of the reaction 12 C(e,e’K) 12 B  Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, June

12 C(e,e’K) 12 B  < 1 MeV FWHM Missing energy (MeV) R esults on 12 C target – Hypernuclear Spectrum of 12 B  g.s. Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, June

Aerogel Kaon selection RICH Kaon selection 12 C(e,e’K) 12 B  Spectroscopy analysis of 12 B  : Aerogel vs. RICH K-selection Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, June

J LAB Hall A E94-107: preliminary comparison with theory for 12 B  hypernucleus Missing energy (MeV) Counts / 200 keV 12 C(e,e’K) 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, June

J LAB Hall A E94-107: preliminary comparison with theory for 12 B  hypernucleus Missing energy (MeV) Counts / 200 keV 12 C(e,e’K) 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, June

R esults from last year run on 9 Be target Analysis of the reaction 9 Be(e,e’K) 9 Li  (still preliminary) Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, June

Missing energy (MeV) Counts / 400 keV 9 Be(e,e’K) 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, June

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, June

F irst R esults from current experiment on WATERFALL target Analysis of the reaction 16 O(e,e’K) 16 N  (almost online) and 1 H(e,e’K)  (elementary reaction) Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, June

2005 E-94107: Running on waterfall target Be windows H 2 O “foil” Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, June

2005 E-94107: Preliminary spectra of missing energy 1 H (e,e’K)  16 O(e,e’K) 16 N  Low counting levels above E thr. 16 O(e,e’K) 16 N  Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, June

C onclusions: Experiment E 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 performs 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  - interesting comparison with theory for 12 B  and 9 Li . VERY Promising physics is coming out from the presently running experiment on 16 N  hypernuclear spectroscopy Mauro Iodice – e94107 update - Hall A Collaboration Meeting, JLAB, June