Two- and multi-particle correlation studies

1. Two- and multi-particle correlation studies • Correlations as probes for spectroscopy and dynamics [dynamics] [spectroscopy] Resonance decay/Invariant mass spectroscopy Spectroscopic properties of unbound states Nuclear equation of state; Symmetry energy Collaboration: INFN, CNRS (France), TAMU (USA)

2. Plans • Shorter term project: • Correlation femtoscopy experiments with stable beams at GANIL and stable and exotic beams at LNS • Physics (high priority on light particle detection, High statistics!) • Observables • Detector needs • Typical experiments • Possible proposals for campaigns in 2015-2016 (?) • Longer term projects: • Inclusion of neutron correlations • Decay spectroscopy with magnetic spectrometers + correlators • Low energy reactions: CN decay  femtoscopy and multi-particle invariant mass spectroscopy in CN decay

3. A - Physical systems: HIC collision, particle emitting sources Projectile Target Unbound states Secondary decays and Spectroscopy tools Equation of State TIME Pre-equilibrium, stopping, compression Fragmentation Expansion • Spectroscopic tools: • Primordial source reconstruction • Resonance decays • Dynamics: • Femtoscopy(HBT) • Correlation functions B - Techniques and observables Correlators (MUST2, FARCOS) + 4π event characterizer (Chimera, Indra) C – Detector needs!

4. “interdisciplinary research topic” • From low to relativistic energies: sharing of analysis techniques and ideas • WPCF-2013, Workshop on Particle Correlations and Femtoscopy, Catania, Nov 2013: large participation and exchanges with LHC and RHIC, www.ct.infn.it/wpcf2013 • Interactions in three particle correlation studies (three-pion @ Alice Vs Three-alphas @ Chimera, Birmingham, …) • Exchanges in projectile/target cluster structure effects on elliptic flow • Femtoscopy: energy-scan and studies over widely varying systems • 3D Vs. 1D imaging studies • Effects of collective motion on correlations • Resonance decays: in-medium effects on spectroscopy, recombination and rescattering, … • Relevance to multi-particle correlations in halo nuclei (exotic beam studies at Isol and In-Flight facilities

5. Building correlations Final-state interactions • Detection needs/ requirements: • Shape of resonances: high angular and energy resolution • Low q-regions: high granularity and angular resolution Resonances Coulomb anti-correlation (repulsion) 1+R(q) 6Li deuteron-alpha …can be extended to three- and multi-particle correlation functions… q (MeV/c)

6. 1+R(q) p-p Source function Data q (MeV/c) 0 20 40 60 80 100 S(r) 0 0 4 6 8 r (fm) Shape measurements of pp correlations G. Verde et al., PRC65, 069604 (2002) Output Input “Size” Source funnction S(r): “Space-time” profile of decaying system Need high resolution in measuring the shape of peak!

7. Present challenge: symmetry energy Asymmetry term B.A. Li et al., Phys. Rep. 464, 113 (2008) Many approaches… large uncertainties…. Microscopic many-body, phenomenological, variational, … ZH Li, U. Lombardo, PRC74 047304 (2006) Stiff Esym(MeV) Esym(MeV) Soft Need HIC at intermediate energies + Ranges of N/Z (δ2) enhance Esym effects Brown, Phys. Rev. Lett. 85, 5296 (2001) Fuchs and Wolter, EPJA 30, 5 (2006)

8. neutron-neutron 7 5 3 1 1.5 1+R(q) 1.0 proton-proton 0.5 0.0 4 3 proton-neutron 2 1 q (MeV/c) Symmetry energy and correlation functions IBUU simulations 52Ca+48Ca E/A=80 MeV Central collisions Correlation functions Lie-Wen Chen et al., PRL (2003), PRC(2005) Stiff Soft • Proton-proton correlation sensitive to Esym • nn and np also… but difficult… (later projects) •  …meanwhile use: t-3He, t-t and 3He-3He

9. First results from MSU on Ca+Ca – 80 MeV/u MSU: HiRA + 4pi 40Ca+40Ca Vs. 48Ca+48Ca E/A = 80 MeV Correlations + 4pi array Size effect or N/Z effect? What is the role of space-time ambiguities?  Need new experiments and better 4π characterization event-by event

10. 112Sn+124Sn E/A=50 MeV bred=0-0.4 dN/dt PT/m > 0.2 PT/m > 0.3 time (fm/c) Isolating particle at the early dynamical stage Sn+SnE/A=50 MeV bred=0-0.4 Early B. Barker et al. Late

11. Experimental data (preliminary) Xe+Au E/A=50 MeV MCP=36 (~bred<0.3) Lassa@MSU PT/m > 0.2 Proton energy spectra with pT > 0.15 No PT gate Source functions pp correlations Moving source fit: single-particle emitting source moving with v ~vNN E.V. Pagano T. Minniti, G. Verde, et al., to be submitted

12. Effects of pT gates on pp correlations Preliminary Xe+Au E/A=50 MeV bred<0.3 Fraction of dynamically emitted protons (%) - fdynamical Source function size – r1/2 Source size fdynamical Increasing relevance of dynamical emissions T. Minniti, G. Verde, et al., in progress (pT/m)min (pT/m)min • Consistent with increasing importance of dynamical sources at high PT • Trend at high PT of source size need more understanding… Work in progress

13. Typical experimental setup Correlators (FARCOS + MUST2) • Needs: • 4π for characterization of collision events: b, reaction plane, flow! • Correlators: • High resolution in (Theta, Phi, E) • Large solid angle coverage: statistics AND changing kinematics with Ebeam 4π det + other physics cases in same experiment: Campaigns “a-la-indra” Example: G. Verde and J. Natowitz –> comparisons femtoscopic radii vs coalescence radii (discussed briefly during last IWNDT meeting in College Station)

14. Must2: Mur àStrip • Mostly used for direct reactions with exotic beams (GANIL, RIKEN) • Optimized for high energy and angular resolution detection of light particles: p, d, t, 3He, 4He, 6He, …, Li isotopes… (dynamic range limited) • ASIC electronicsby the same team that develops GET electronics (similar ASIC concepts, no digitalization, …) • In our project: best suited at large angles in the lab frame, dominated by light particle emissions • Very flexible

17. Multifragmentation Flow Pre-equilibrium emission Central Symmetry energy at very low densities? (TAMU)  ρ≈ 0.01∙ρ0 Clustering (~alphas) at small densities affects Esym C.J. Horowitz et al., NPA776, 55 (2006), G. Wanatabe et al., PRL103, 121101 (2009) Esym(ρ) not vanishing at very low ρ NIMROD @ TAMU Symmetry Energy at very low densities 64Zn+92Mo,197Au 40Ar, 64Zn+112,124Sn E/A=35 MeV Emission volumes and densities from coalescence analyses of energy spectra! Esym(MeV) Density ρ(fm-3) Coalescence Vs. Femtoscopy? statisctial Vs. dynamical J.B. Natowitz et al, PRL 104 (2010) 202501 R. Wada et al., PRC85, 064618 (2012)

18. 10C* Invariant mass spectroscopy: “gratuit” in the same experiment! Not only EoS… Several unbound species in just one single experiment! Expansion • HIC and correlations as a spectroscopic tool • Cluster states, Hoyle states, BEC, … • Same experiment • Access to invariant masses, spin, branching ratios for simultaneous and sequential decays • Compare direct reactions to HIC and in-medium decay

19. Spectroscopy  Dynamics Xe+Au E/A=50 MeV 8B p-7Be 10B α-6Li 8Bep-7Li p-p-16O correlation function 18Nep+p+16O 1+R 9Bp+α+α 12Cα+α+α

20. 2.32 3+ 1.4 (?) 0.774 1+ p+7Be 8B Example: 8B unbound states in central HIC Xe+Au E/A50 MeV Central collisions p-7Be correlations States of 8B  p+7Be W.P. Tan et al. Phys. Rev. C69, 061304 (2004) Relative height of resonances constraints the spin of states

21. 10C  6Be+α (2p+α)+α 10C  8Be+p+p (α+α)++p Ek(MeV) 10C  9B+p (p+α+α)+p Example: 2α-2p correlations : states in 10C* 4-particle correlation functions: p-p-α-α F. Grenieret al., Nucl. Phys. A811 (2008) 233 Constraining branching ratios for sequential vs simultaneous decays

22. Direct and fragmentation reactions with exotic beams 12Be + p, 12C E/A = 50 MeV 105pps R.J. Charity et al., PRC76, 064313 (2007) HiRA @ MSU Several new states studied

23. Opportunity: fast exotic beams @ LNS Ex: Primary beam: 20Ne E/A=45 MeV/A Production target: 9Be (500 mm) Fragments transported and tagged event-by-event by E-ToF Bρ=2.71 Tm Projectile fragmentation beams 17C ΔE (MeV) 16C DSSD Tagging detector 13B 12Be 10Be 9Li 11Be 6He 7Li Light and medium mass isotopes for direct reactions in inverse kinematics: multi-particle correlations T (ns)

24. Interplays dynamics-spectroscopy • Femtoscopy(dynamics) with light particles (strongly interacting!) needs spectroscopy information: resonances, quantum statistical symmetries, etc. • Spectroscopy information may be extracted from correlations with light complex particles (example: 10Cp+p+α+α)

25. Invariant mass spectroscopy: Direct (FRIBS) Vs. Multifragmentation • Multifragmtation reactions: • Good: high statistics, “clean” stable beams • Bad: not clean states produced, distortions in medium (low density nuclear matter), effects of reaction/production mechanism • Direct reactions with exotic beams: • Good: clean states and analysis methods • Bad: low statistics, low beam quality (tracking required with resolution and rate limitations, …) • Comparisons would be of mutual benefit: • Effects of reaction mechanism on extraction of spectroscopic properties (important for exotic beam studies, structure reaction mechanism!) • In-medium effects on resonance formation and decay • Search for clusters in low density matter (Symmetry energy) • …

26. Experiments: scanning over widely varying systems • Energy scan (E-scan): “wide” range of beam energies (intermediate) – understand space-time ambiguity in emitting source profiles • E/A<35 MeV @ LNS, TAMU(?) • E/A>35 MeV @ GANIL • Mass scan Vs. Isospin scan (A-scan, N/Z-scan) – understand ambiguity in size effects Vs. symmetry energy effects • 40,48Ca+40,48Ca • 58,64Ni+58,64Ni • 112,124Sn+112,124Sn • …and inverse kinematics combinations (ex.: Sn+Ni, etc.), better for coalescence studies

27. Shorter term campaigns –Fermi energies • Reaction systems at GANIL (> 2016?) • N/Z-scan and A-scan: • 40Ca + 40Ca, 48Ca + 48Ca • 58Ni + 58NiCa, 64Ni + 64Ni E/A=40 - 80 MeV • 112Sn + 112Sn, 124Sn + 124Sn • 58Ni + 40Ca, 64Ni + 48Ca (coalescence vsfemtoscopy) • N/Z-scan: • 48Ca + 48Ca, 48Ti + 48Ti E/A=40 – 80MeV • 96Zr + 96Zr, 96Ru + 96Ru E/A=25 - 60 MeV • Reaction systems at LNS (<2017) • N/Z-scan and A-scan: • 40Ca + 40Ca, 48Ca + 48Ca • 58Ni + 58NiCa, 64Ni + 64Ni E/A=25 - 40 MeV • 112Sn+112Sn, 124Sn+124Sn • 58Ni + 40Ca, 64Ni + 48Ca (coalescence vsfemtoscopy) • FRIBS beams: direct reactions and invariant mass spectroscopy

28. Spokesperson of Mus2 project Group Leader NIMROD@TAMU

29. Longer term challenges: neutron-proton correlations nn, np and pp correlation functions  Symmetry energy neutron-proton correlations Correlators Protons EDEN Neutrons Measuring pp, np, nn correlations: LNS: EDEN + MUST2/FARCOS GANIL: DEMON + MUST2/FARCOS G. Verde, Must2 meeting – 14 Nov 2013

30. 1+R(q) q (MeV/c) Correlations at low energies Explosive scenario 16O+ 27Al @ E/A=8.8 MeV Evaporative scenario • Correlation femtoscopy: volumes, emission times, prompt vs evaporative decays, light particle emission chronology, etc. • Multi-particle decay spectroscopy: emission of exotic nuclear systems (p-rich and n-rich) exploratory plans for SPES and Spiral2  Start with stable beam experiments at LNS and GANIL: test experimental techniques in CN reactions (2015-2016?)

31. Documents under construction • Scientific program • Logistics and Technical details • Manpower organization: students for data analysis, organization of calibration tasks (“Indra-like” organization), technical tasks • Letter of Agreement with international partners • Milestones

32. Backup slides

33. Resonance decay (invariant mass) spectroscopy: direct and fragmentation reactions R.J. Charity et al., PRC78, 054307 (2008) New state in 8Be at E*~23 MeV --> sequential: 8Be  7Li + p 7Li  t + α