1. 1 Hadron Physics at J-PARC Shin’ya Sawada 澤田 真也 KEK (High Energy Accelerator Research Organization, Japan) AFTER@LHC, ECT*, Feb. 5. 2013

2. 2 Contents Overview of J-PARC and Hadron Experimental Facility (Hadron Hall) Physics with Low Momentum Secondary Beams Physics with High-Momentum Beams Extension Summary

3. 3 Goals at J-PARC Need to have high-power proton beams  MW-class proton accelerator (current frontier is about 0.1 MW) R&D toward Transmutation at 0.6 GeV Nuclear & Particle Physics at 50 GeV Materials & Life Sciences at 3 GeV

4. 4 Location of J-PARC at Tokai Tsukuba Tokai 1 hour 295 km JAEA J-PARC

5. 5 J-PARC Facility (KEK/JAEA ） Bird’s eye photo in January of 2008 South to North Experimental Areas Neutrino Beams (to Kamioka) JFY2009 Beams 50 GeV Synchrotron Hadron Exp. Facility Materials and Life Experimental Facility JFY2008 Beams 3 GeV Synchrotr on JFY2007 Beams Linac

6. Hadron Experimental Facility (Current Layout) Hadron Hall 50GeV Synchrotron Beam Dump 50GeV Tunnel Ｔ１ Target (30/50% Loss) Test BL Hi-P BL Extension SM1 (2% Loss) T0 0.1% Loss) Switchyard 6

7. experiments in Hadron Hall Beam Dump K1.8 K1.8BR 30~50 GeV primary beam Production target (T1) Approved (stage-2) / (stage-1) / proposed,LOI High momentum line KL K1.1 Hadron mass in nuclei Nucleon quark structure K1.1BR Not constructed yet K - pp bound states K - atomic X rays  mesonic nuclei T violation in K + decay Universality in K + decay  + study by K + n scattering  -e conversion search Hyp. weak decay(A=4) Hyp. weak decay(A=12)  Double charge exch.  mesonic nuclei  p scattering  hypernuclei  hypernuclei  -atomic X-rays  hypernuclear  rays Neutron-rich  hypern. Pentaquark  + search K - pp bound state  mesonic nuclei  hypernuclear  rays  -nuclear systems YN scatering  + hypernuclei K 0 L rare decays K-K- p p  p n Slide By H.Tamura 7 7

8. Season of Fruits at Hadron Hall Comes! Beam Intensity is being upgraded.

9. 9 Contents Overview of J-PARC and Hadron Experimental Facility (Hadron Hall) Physics with Low Momentum Secondary Beams Physics with High-Momentum Beams Extension Summary

10. Physics with Low Momentum Secondary Beams So far there are only low-momentum beam lines. Strangeness nuclear physics –With (pi, K), (K, pi), and (K-, K+) reactions Other hadron physics –Many strangeness related, but a few non-strange. Low Momentum Secondary Beams –Pions and Kaons <2 GeV/c at K1.8 beam line Momentum was selected so that the production cross section of the Xsi baryon is at the maximum. Major goal is S=-2 hypernuclei (Xsi nuclei and double-Lambda nuclei). Used also for (pi, K) reaction for single hypernuclei. –Pions and Kaons <1.1GeV/c at K1.8BR and K1.1 beam line Single Lambda hypernuclei Gamma ray spectroscopy Search for K-pp bound states 10

11. 11 N Z N u ~ N d ~ N s Higher density Strangeness in neutron stars (  > 3 - 4  0 ) Strange hadronic matter (A → ∞) ,  Hypernuclei ,  Hypernuclei Strangeness 0 -2 “Stable” Three Dimensional Nuclear Chart

12. Single strangeness experiments E19 (published): Pentaquark search E10 (took data): Neutron-rich hypernuclei with double-charge exchange E13 (coming soon): Gamma ray spectroscopy of hypernuclei E15 (took some data): Search for K - +p+p bound state … (many waiting) 12

13. E19: Pentaquark Search search for Θ + in p(π –, K – ) target : liquid H2, 0.86g/cm2 at K1.8 beamline + SKS beam momentum : – p π =(1.87,1.92,2.00GeV/c) 4.8 x 10 11  on target for each p π beam intensity : 10 7 /spill(2sec.) beam time : 160 hours Yield : 10 4 events for each momentum Sensitivity : 75nb/sr Sensitivity : 75nb/sr  confirm the existence of Θ +  confirm the existence of Θ + 13 SKS: ideal for Θ + detection large acceptance : 0.1sr ΔM = 2.5MeV FWHM E19 took the first physics data with p=1.92 GeV/c in Oct/Nov, 2010, and p=2.0 GeV/c in Feb, 2012.

14. E19: Pentaquark Search 14

15. Study on 6 Λ H hypernucleus by the (π -,K + ) reaction at J-PARC Hitoshi Sugimura Kyoto University/JAEA For J-PARC E10 Collaboration 6/6/201315International Nuclear Physics Conference 2013

16. J-PARC E10 experiment 6/6/2013International Nuclear Physics Conference 201316 Double Charge-Exchange (DCX) N~Z (I=0 or 1/2) N>>Z (I=3/2 or 2) ordinary nuclei J-PARC E10 Non Charge-Exchange (NCX) hyperfragments by emulsions exp.  -hypernuclei π - +p+p->K + +n+Λ

17. 6 Λ H production by FINUDA 6/6/2013International Nuclear Physics Conference 201317 6 Li(stopped K -,π + ) reaction 6 Li(stopped K -,π + ) reaction Measured formation and weak decay in coincidence Measured formation and weak decay in coincidence cut on T(π + )+T(π - ) cut on T(π + )+T(π - ) 3 events of candidates 3 events of candidates 17 M. Agnello et al., FINUDA Collaboration, PRL 108 (2012) 042501

18. Experimental Setup SDC3 SDC4 SFT AC LC TOF BFT BH2 SSD BC3 BC4 SDC2 BH1 GC π-π- K+K+ J-PARC K1.8 Beam Line 6/6/201318International Nuclear Physics Conference 2013 K1.8 Beamline K1.8 Beamline -1.2GeV/c π - Beam -1.2GeV/c π - Beam Δp/p ~3.3x10 -4 Δp/p ~3.3x10 -4 Momentum is measured by the Momentum is measured by the Transfer Matrix Transfer Matrix BFT(x)-BC3,4(x,y,x’,y’) BFT(x)-BC3,4(x,y,x’,y’) SKS Spectrometer SKS Spectrometer Central Momentum 0.9GeV/c Central Momentum 0.9GeV/c Δp/p~1.0x10 -3 Δp/p~1.0x10 -3 Momentum is calculated or estimated Momentum is calculated or estimated Runge-Kutta method Runge-Kutta method SFT,SDC2(x,y,x’,y’)-SDC3,4(x,y,x’,y’) SFT,SDC2(x,y,x’,y’)-SDC3,4(x,y,x’,y’) Scattered Kaon identified TOFxLCxAC in Scattered Kaon identified TOFxLCxAC in online trigger online trigger SKS

19. Calibration Runs Results of analysis Results of analysis +1.20GeV/c 12 C(π +,K + ) 12 Λ C +1.20GeV/c 12 C(π +,K + ) 12 Λ C - 1.37GeV/c p(π -,K + )Σ - - 1.37GeV/c p(π -,K + )Σ - +1.37GeV/c p(π +,K + )Σ + +1.37GeV/c p(π +,K + )Σ + Preliminary g.s.(s Λ ) 12 C(π +,K + ) 12 Λ C ΔB Λ :2.8MeV/c 2 (FWHM) Ex(p Λ ) p(π +,K + )Σ + ΔM:2.6MeV/c 2 (FWHM) Preliminary Measure: 1188.41MeV PDG: 1189.37MeV Yield : ~2000 events Preliminary p(π -,K + )Σ - ΔM:2.5MeV/c 2 (FWHM) Measure:1200.39MeV PDG: 1197.45MeV Yield : ~6000events Σ-QF Λ-QF 6/6/201319International Nuclear Physics Conference 2013 Yield (g.s): ~600events

20. Preliminary Σ- continuum Λ- continuum Missing Mass 6/6/2013International Nuclear Physics Conference 201320 Missing Mass[GeV/c 2 ] Counts/MeV Missing Mass[GeV/c 2 ] Could measure not only Λ-continuum region but also Σ-continuum region. Could measure not only Λ-continuum region but also Σ-continuum region. Back ground level is enough lower than Λ-continuum. Back ground level is enough lower than Λ-continuum. According to simple extrapolation of Λ-continuum, we observed some excess at the low mass region. But it is too early to conclude at this moment. According to simple extrapolation of Λ-continuum, we observed some excess at the low mass region. But it is too early to conclude at this moment. Production cross section of 6 Λ H is smaller than we expected (10nb/sr). Production cross section of 6 Λ H is smaller than we expected (10nb/sr).

21. E13: Hypernuclear  Spectroscopy 21 High-precision (  E ～ 3 keV FWHM) spectroscopy with Ge detectors 1. YN, YY interactions Unified picture of B-B interactions Understand short-range nuclear forces Understand high density nuclear matter (n-star)  Level energies ->  N spin-dependent forces, Charge symmetry breaking,  N-  N force,… 2. Impurity effects in nuclear structure Changes of size/shape, symmetry, cluster/shell structure,.. B(E2), E(2 + ) -> shrinking effect, deformation change 3. Medium effects of baryons probed by hyperons B(M1) ->    in nucleus E13

22. Double-strangeness hypernuclei soon With the improvement of the proton beam intensity, double-strangess experiments with (K-, K+) become possible soon. E07: Systematic Study of Double Strangeness System with an Emulsion- Counter Hybrid Method 22 PS-E176 in ~80 Ξ stops Double-Hypernucleus with sequential decay surely exists. Δ B  = 1.01 ± 0.20 MeV in ~700 Ξ stops 10 5 0 5 10 (  m) A B  #1 #2 #3    #2 ΞΞ #1 +6 cand. N AGARA event for  6  He PS-E373

23. Double-strangeness hypernuclei soon E07: Systematic Study of Double Strangeness System with an Emulsion-Counter Hybrid Method –Physics 1) S=-2 nuclear chart by ~10 2  Z via 10 4   - -stopping events. =>  B  of several nuclides will provide definitive informationon  interaction and structure of S=-2 nuclei. 2) H-dibaryon state in S=-2 system ? => measure A-dependence of  B  &  decay mode of  Z. 3)   -nucleus potential => detection of twin hypernuclei => First measurement of X-ray of   - atom 23

24. 24 Contents Overview of J-PARC and Hadron Experimental Facility (Hadron Hall) Physics with Low Momentum Secondary Beams Physics with High-Momentum Beams Extension Summary

25. Physics with High-Momentum Beams “High-momentum beam line” (+ COMET beam line) has been funded! High-momentum primary proton beam (30GeV) –Meson mass modification inside nuclei –Dilepton measurement for nucleon and baryon structure High-momentum meson (pion) beam (~<15 GeV/c) –Pion-induced Drell-Yan? –Baryon spectroscopy with pion beams. 25

26. High-p and COMET New primary Proton Beam Line = High-momentum BL + COMET BL High-momentum Beam Line –Primary protons (~10 10 – 10 12 pps) E16 (phi meson) is considered to be the first experiment. –Unseparated secondary particles (pi, …) High-resolution secondary beam by adding several quadrupole and sextupole magnets. COMET –Search for  to e conversion –8 GeV, 50 kW protons –Branch from the high-momentum BL –Annex building will be built at the south side. 26

27. New Primary Proton Beam Line 27 COMET High-p Separation

28. 28 Mass modification of vector meson Hot/Dense Matter Vector meson mass at normal nuclear density m*/m=1-k    Hatsuda&Lee PRC46(92)R34 )  m = 130 MeV at    m = 20~40 MeV at   Restoration Chiral Symmetry QCD Vaccum Spontaneous Breaking of

29. Results of a previous experiment (KEK-PS E325): Invariant mass spectra of   e+e- Results of a previous experiment (KEK-PS E325): Invariant mass spectra of   e+e-  <1.25 (Slow)1.25<  <1.75 1.75<  (Fast) Large Nucleus Small Nucleus PRL 98(2007)042501 29

30. 30

31. 31 J-PARC E16: Electron pair spectrometer to explore the chiral symmetry in QCD 10 7 interaction (10 X E325) 10 10 protons/spill with 0.1% interaction length target  GEM Tracker eID : Gas Cherenkov + Lead Glass Large Acceptance (5 X E325) primary proton beam at high momentum beam line + large acceptance electron spectrometer velocity dependence nuclear number dependence (p  Pb) centrality dependence  systematic study of mass modification

32. Possible hadron exps at high-momentum BL Sea quark structure through Drell-Yan measurement –Currently the E906/SeaQuest is running at Fermilab with 120-GeV protons to see d-bar/u-bar asymmetry. –Larger x possible with 50-GeV protons at J-PARC. J-PARC is currently operated with 30-GeV and there are no demands of 50-GeV operation from other experiments, which needs modification of a part of the accelerator components. –There could be other possibilities of physics with dimuon measurement such as, J/Psi measurements to see the nucleon sea, dimuons from pion/kaon induced reactions to see meson-like substructure of a nucleon. Spin related quantities –Polarized beam relatively far future. –Polarized target would be available in the near future. –Measurement such as Bohr-Mulders can be carried out even with unpol. Drell-Yan measurements.

33. J/Psi: gg or q-qbar? 33 Lingyan Zhu et al., PRL, 100 (2008) 062301 Gluon distributions in proton and neutron are very similar at 800 GeV. At much lower energies, J/Psi might be produced by q-qbar annihilation.  Azimuthal angle dependence. If J/Psi production is q-qbar annihilation, J/Psi becomes a tool to investigate quark structure of nucleon at lower energies.

34. Unseparated Secondary Beam Intensity beam loss limit @ SM1:15kW (limited by the thickness of the tunnel wall) [GeV/c] extraction angle ： 5°  smaller angle possibility being investigated with 15kW beam loss

35. Exclusive Pion-Induced Drell-Yan Process DA characterizes the minimal valence Fock state of hadrons. DA of pion are also explored by pion-photon transition form factor in Belle and Barbar Exps. TDA characterizes the next- to-minimal valence Fock state of hadrons. TDA of pion-nucleon is related to the pion cloud of nucleons. Bernard Pire, IWHS2011 35

36. Accident Radiation accident occurred at Hadron Hall on May 23 rd. –Due to a malfunction of the beam extraction system of the 50 GeV synchrotron, a proton beam was delivered to the gold target of the Hadron facility within a very short time (30GeV, 2E13protons in ~5ms). As a result, the gold target is considered to have momentarily reached an extremely high temperature and a part of the target was damaged. Radioactive material then leaked into the hadron experimental hall and some workers were externally and/or internally exposed to radiation. –Operation of ventilation fans of the hall resulted in leak of radioactive material out of the radiation controlled area of the Hadron Experimental Facility. The data logs of radiation dose rates at monitoring posts at the border of the J-PARC site showed no signatures. However, at three monitoring posts and stations of a neighboring JAEA facility, momentary increases of the radiation dose rate were observed. It is assessed that the released radioactive material was diluted and attenuated as it dispersed in a narrow strip towards the west. The maximum integrated radiation dose has been estimated even at the site boundary closest to the Hadron Experimental Facility was 0.29 µSv (preliminary). –All the J-PARC facilities have been shutdown since the accident. A full investigation of the cause of the accident is now underway along with the complete review of safety practices and emergency procedures at all J-PARC facilities. Our first priority is to restore public trust in the facility by developing and implementing measures to prevent the reoccurrence of an accident and to provide a safe experimental environment for users and workers. 36

37. 37 Summary Physics experiments have started at the Hadron Hall of J- PARC, and the first physics paper is being published from the E19 experiment. So far experiments with lower momentum pions/kaons are being carried out. The funding for the high-momentum beam line with COMET has been approved by the government. The construction is expected to start soon. Mass shift of phi meson would be the first experiment, and other experiments are being discussed. J-PARC is now very busy to respond to the accident. We don’t have any forecast on the schedule, but we make our best.