Hiroyuki Sako ( ASRC/J-PARC, JAEA ) f or J-PARC HI Collaboration QM2014, Darmstadt

1. Towards the Heavy-Ion Program at J-PARC 1. Introduction2. Heavy ion acceleration scheme3. Physics goals4. Experimental design5. Summary Hiroyuki Sako (ASRC/J-PARC, JAEA) for J-PARC HI Collaboration QM2014, Darmstadt

2. Introduction LHC RHIC SPS J-PARC will achieve designed beam power with proton beams in a few years 1MW at 3GeV 0.75MW at 30 GeV We started discussing experimental and accelerator schemes for heavy ion program at J-PARC We aim at studies of QCD phase structures in high baryon density regime at J-PARC RHIC low energy scan, NICA, FAIR J-PARC GSI-SIS mB Hadron Seminar @J-ParcTakao Sakaguchi

3. 400 MeV H-Linac J-PARC Tokai, Japan 3 GeV Rapid Cycling Synchrotron (RCS) 1 MW 50 GeV Main Ring Synchrotron (MR) [30 GeV at present] 0.75 MW Hadron Experimental Hall (HD)

4. Low and High energy programs “Low energy” program (Linac) for unstable nuclei research • Ion species • Ne, Ar, Fe, Ni, Kr, Xe,…,U • Beam energy • 1- 10 AMeV (U) • Beam current • 10-30pmA • 10ms, 25Hz “High Enegy” Program (50 GeV MR) • Ion species • p, Si, Cu, Au, U AuU • Baryon density • 7.5r0 8.6r0 (JAM ) • Duration at r>5r0 • 4  7 fm/c • Beam energy • 1 - 11.6 AGeV (U) ( • Possibly 19 AGeV() • Rate • 1010-1011 ions per cycle (~a few sec)

5. Possible accelerator schemes New Ring A New LINAC 3GeV RCS 50 GeV MR B New LINAC

6. An example of acceleration scheme (with new HI Linac) 11.5AGeV 13AMeV 190AMeV 197Au79+ 197Au32+ 197Au32+ Linac stripping • MR • RCS • RFQ • 7 x IH-DTL • ShortCavities • Multi-turn injection 2 bunch 8 bunch Chopping=60% Efficiency=100% 3.1x1010/pulse 1.0x1010/bunch Au32+, 10pmA CW 25Hz, 0.5ms 8.0x1010/MR cycle (upper limit) Y. Liu, J-PARC HI Meeting

7. Physics goals • Systematic and precise hadron measurements • Identified particle spectra (K/p,…) • Multi-strange baryons • Correlations (Event-by-event fluctuations, flow, HBT) • Electrons and Muons • Di-lepton spectra of r/w/f • Rare particles • Hypernuclei • Exotic hadrons • L(1405) • H-dibaryon • K-pp • Charm • J/y, D • Photons • Thermal photons from QGP P. Braun-Munzinger, JHI2014 workshop J-PARC Maximum baryon density at freezeout (Randrup, PRC74(2006)047901)

8. Strange meson/baryons Strangeness enhancement at ~10GeV is connected to high baryon density via hyperons Energy scan with high statistics J-PARC A. Andronic, et al, Nucl. Phys. A 837 (2010) 65

9. Hypernuclei Maximum yield at J-PARC • coalescence of high-density baryons Hypernuclei S=-3 in HI collisions Closed geometry configuration for projectile region? J-PARC A. Andronic, PLB697 (2011) 203 KEK Report 2000-11 Expression of Interest for Nuclear/Hadron Physics Experiments at the 50-GeV Proton Synchrotron

10. Particle production rates Beam : 1011 Hz 0.1% target  Interaction rate 108 Hz Centrality trigger 0.1%  100kHz DAQ rate = 100kHz In 1 month experiment: r,w,fee108-109 D,J/Y106(20AGeV) (103(10AGeV)) Hypernuclei 105 -1010 Hypernuclei Dilepton Charm Ref: HSD calculations in FAIR Baseline Technical Report (Mar 2006) A. Andronic, PLB697 (2011) 203

11. Experimental requirements • High rate capability • Fast detectors • Silicon trackers, MPGD (e.g. GEM) trackers, … • Extremely fast DAQ • >= 100kHz • High granularity Pixel size < 3x3mm2 (at 1m, q<2deg, 10% occupancy) • Large acceptance (~4p) • Multiplicity for e-b-e fluctuations • Backward physics (target fragment region)

12. TOF (5m from target) Muondipole PreliminarySpectrometer Design Muon tracker Top View TOF Dipole (BL=1.5Tm) RICH Solenoid (BL=1Tm) 30o Silicon pixel/strip trackers ZCAL 10o 2m Multiplicity counter target GEM trackers RICH Aerogel +gas 1.5m 2m 1m 0.3m 1m hadron-ID (q<117o) e-ID : q<30o m-ID : q<25o 20o = mid rapidity Centrality MC + ZCAL GEM Trackers EMCAL

13. Particle-ID methods e-pseparation RICH (C5F12) p<3.4GeV/c (20mrad) m – p separation • p<0.8 GeV/c TOF with 30ps (MRPD) in 5 m TOF • p=0.8-1.5GeV/c RICH (Aerogel) • p>1.5 GeV/c (20mrad) Fe absorbers + Trackers EMCAL (e,gID) PbWO4 15X0(14cm) Dual radiator RICH (HERMES type)

14. GEANT4 simulation • JAM model U+U (10AGeV) • Full physics processes

15. Simulation results(Preliminary) Momentum vs m2(dipole spectrometer) pT (GeV/c) p+ p K+ Charge x p (GeV/c) K- p- rapidity M2 (GeV/c2) Acceptance TOF Resolution 50ps Position resolution Silicon trackers : 14-23mm GEM trackers: 0.2-0.5mm dp/p=1.3% (solenoid) 1% * p (GeV/c) (dipole)

16. Simulated di-electron spectrum(preliminary) p0 Based on pi0 spectra ofJAM Other hadrons mT-scaled b<1fm (0.25% centrality) Momentum resolution 2% Electron efficiency 50% No detector response 1011 events ⇔100k events/sec x 1 month running w r f Calculations by T. Gunji and T. Sakaguchi

17. Summary • A heavy ion program at J-PARC is under discussion • Preliminary experimental setup has been designed • Acceleration schemes are under design Prospects • Design of accelerators and experiments • A first complete design by Mar 2015 (White paper) • Detector R & D • J-PARC E16 (electron/hadron in p+A) • J-PARC proton beams (1010 Hz) • Starting in 2016 • We wish international collaboration

18. J-PARC HI Collaboration S. Nagamiya (JAEA/KEK/RIKEN) H. Sako, K. Imai, K. Nishio, S. Sato (ASRC/JAEA) H. Harada, P. K. Saha, M. Kinsho, J. Tamura, (J-PARC/JAEA) K. Ozawa, Y. Liu (J-PARC/KEK) T. Sakaguchi (BNL) K. Shigaki(Hiroshima Univ.) T. Chujo (Univ. of Tsukuba) T. Gunji (CNS, Univ. of Tokyo) M. Kaneta (Tohoku Univ.)

19. Backup

20. U+U at 10 AGeV(Preliminary) Acceptance

21. PID and momentum (Preliminary) Momentum vs m2 (with TOF) p Charge*P (GeV/c) p+ K+ TOF Resolution 50ps Position resolution Silicon trackers : 14-23mm GEM trackers: 0.2-0.5mm dp/p 1.3% (solenoid) 1%/GeV (dipole) pbar K- p- M2 (GeV/c2) Momentum resolution Dp/p P(GeV/c)

22. Three Extreme Region on Chart of Nuclei Search for Heaviest N=Z Nuclei ( R. Grzywacz ) Search for Super-heavy Nuclei ( S. Heinz ) Search for Heaviest N=126 Nuclei ( K. Nishio) SHE β-stability line 150 N=126 120 114 100 184 N=Z Z 82 50 50 126 28 82 20 50 28 200 50 100 150 N

23. Search for Super-Heavy Nuclei 238U + 248Cm (6MeV/u ) Neutrons 248Cm 238U by V. Zagrebaev (FLNR) Protons

24. Search for Heaviest N=126 Nuclei 126 α Proton Drip Line Fm 100 EC/ β+ Es β－ Cf 98 226Fm sf Bk Cm 96 Am Protons α Pu 94 220Pu Np T1/2 > 1μs U U α 92 Pa Th 90 Th α Ac 88 82Kr + 140Ce → 222Pu* → 220Pu 82Kr + 144Nd → 224Cm* → 222Cm 82Kr + 144Sm → 226Cf* → 224Cf 120 125 130 135 140 Neutrons New Region Predicted by H. Koura, ASRC/JAEA

25. m/p separation with RICH P<0.8GeV/c • TOF (MRPD) • 3s separation st=20ps , L=3m 0.8<p<1.5GeV/c RICH(aerogel) P>1.5 GeV/c Fe absorbers +trackers

26. Required pixel size at 10% occupancy at 1m from the target

27. Heavy-ion programs in the world References RHIC: A. Fedotov, LEReC Review, 2013 FAIR: FAIR Baseline Technical Review, C. Strum, INPC2013, Firenze, Italy; S. Seddiki, FAIRNESS-2013 NICA : A. Kovalenko, Joint US-CERN-Japan-Russia Accelerator School, Shizuoka, Japan, 2013

30. Baryon densityfrom light to heavy ions r/r0 10 AGeV/c Au+AuU+U • Baryon density • 7.5r0 8.6r0 • Duration at r>5r0 • 4  7 fm/c U beam is necessary at J-PARC! JAM model Y. Nara, et al, Phys. Rev. C61,024901(1999)

31. U+U at 5 AGeV/c

32. U+U at 1 AGeV/c

33. See Presentation by Masashi Kaneta KenIchi Imai, J-PARC HI meeting (2013/4/24)

34. Centrality Trigger Narrow centrality cut taking advantage of high rate beams • Ultra-central • Many narrow Centrality ranges Impact parameter resolution ~0.62 fm

35. Beam transport lines to MLF to MR RCS Injection system of RCS for Au beam H V Ring twiss(bx,by) at the ext. straight HI inj. Ext. KMs Ext. septa QDL QDX QFL QFM Original H-inj. Candidate HI Injection-BT H. Harada

36. Rapidity and pt distributions 10AGeV/c 5AGeV/c 1AGeV/c

37. Dileptons at J-Parc energy Axel Drees • Landscape for J-Parc • Intermediate Mass Range • DDbar is very hard • QGP thermal radiation is on • Low Mass Range • in-medium modification of vector mesons (link to chiral symmetry restoration) • Thermal radiation T. Sakaguchi@J-Parc HI workshop

38. Photon feasibility study • 0.1 T events 1<y<2, b<1fm • Blue: pi0, Black: eta, Red: decay photons from pi0 and eta • Direct photon signal is assumed to be 2% of background photons • Statistical error only • No hadron contamination, photon efficiency is taken into account. T. Sakaguchi@J-Parc HI workshop

39. γ e- e+ e+ π0 e+ e- π0 π0 γ e- γ Electron feasibility study • Huge background is a problem • Very small jet-originated background • No cross-pair • No charm contribution • Base on pi0 spectra obtained from JAM event generator • Other hadrons mT-scaled • 1<y<2 (in lab), b<1fm (0.25% centrality) • 0.1T events (by one month running) T. Sakaguchi@J-Parc HI workshop

40. Beam Energy Scan of dielectrons • LMR excess observed for all energies • systematic measurement of excess • Model calculations appear to provide robust description from RHIC down to SPS energies • Measurements consistent with in-medium ρbroadening • expected to depend on total baryon density T. Sakaguchi@J-Parc HI workshop

41. Photon calculation • Using UrQMD, low pT photons are calculated at FAIR energy • arxiv:1211.2401 • Bremsstrahlungpp -> ppg is dominant • Elliptic flow is estimated of the order of 1-2% T. Sakaguchi@J-Parc HI workshop

42. Centrality cut

43. Solenoid spectrometer B=2T • Pixel size (<6x6mm2 at 1m at q>10o) pTcut=0.26GeV/c

44. Dipole spectrometer (new) B=2T • Pixel size (<6x6mm2 at 1m at q<10o)

45. U+U at 5 AGeV/c Mid-rapidity ~ 25 deg ynn=1.2

46. U+U at 1 AGeV/c Mid-rapidity ~ 30 deg ynn=0.5

47. Summary of acceptance and pixel size Acceptance Required pixel size at 10% occupancy at 1m from the target

48. Acceptance(p+) q=30o q=117o q=2o

49. Acceptance (K+) q=30o q=100o q=2o