Münster, 23.03.11

Production of Hypernuclei at FAIRProduction of Hypernuclei at FAIR

T. Gaitanos, A.B. Larionov, U. MoselT. Gaitanos, A.B. Larionov, U. Mosel

IntroductionIntroduction

The hybrid GiBUU+SMM approachThe hybrid GiBUU+SMM approach

Giessen-BUU (GiBUU), SMM, combined GiBUU+SMM

HypHIHypHI project: Li(C) project: Li(C)+C@2AGeV+C@2AGeV

Reaction dynamics, spectator fragmentation, results on single-Λ hypernucleiPANDA subproject: pbar+X@(3-5)GeV

Reaction dynamics & strangeness yields, decay of residual source, predictions on

single-Λ and double-Λ hypernucleiFinal remarksFinal remarks

mailto:+C@2AGeV

Münster, 23.03.11

Introduction…Introduction…

hyperon-baryon hyperon-hyperonhyperon-hyperon

explore

crucial to understand the strangeness sector of the hadronic EoScrucial to understand the strangeness sector of the hadronic EoSdirect implications for nuclear astrophysics (max. mass of neutron stars)direct implications for nuclear astrophysics (max. mass of neutron stars)

antiproton-nucleus reactionsantiproton-nucleus reactionsHypHI: HypHI: HHeavy-eavy-IIon collisionson collisions

Λ,Σ,π ,Κ,.. .

Λ,Σ,π ,Κ,.. .

Münster, 23.03.11

Relativistic hypernuclei…Relativistic hypernuclei…

Production of hypernuclei in relativistic HIC / Production of hypernuclei in relativistic HIC / pp+X+X hyperon production: pp->pΛK / pp->ΛΛ,ΞΞ, (+) π,ρ,ω ,... (σ

abs ~ 20mb)

+ Secondary rescattering (A.B. Larionov's talk for details)Multiple coalescence of hyperons with fragments

Theoretical frameworkTheoretical frameworkPhase-Space evolution Phase-Space evolution Transport approaches (INC,BUU,RBUU,CBUU,(Ur)QMD,HSD,…)Description of fragment formation Description of fragment formation Statistical picture (SMM, Botvina & Mishustin)Description of hypernuclei formation?Description of hypernuclei formation?Phase-Space coalescence in coordinate and in momentum space

π

ΛΛ

ΛΛ

π

ΛΛ

ΛΛ

ΚΚ

ΚΚ

ΛΛΞΞ

p

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Giessen BUU…Giessen BUU…Initial non-equilibrium stageInitial non-equilibrium stage

(http://gibuu.physik.uni-giessen.de/GiBUU)(http://gibuu.physik.uni-giessen.de/GiBUU)Relativistic mean-fieldRelativistic mean-field

Non-linear Walecka model (soft EoS) Lalazissis parametrization→

Antibaryon-meson couplings: gω=-ξg

ω, g

σ=ξg

σ

Isovector gρ (anti)baryon-meson interaction (no m* isospin splitting), coulomb

Collision term:Collision term: as usual … +

primary: pp->mesons

Primary: pp-> ΛΛ, ΞΞ (data)

Secondary: ΛΛ( Σ)Ξ Β (data+Nijmegen-calc.), KB->ΞK (data), ΛΒΣB (data)

Münster, 23.03.11

Numerical realization (Test-Particle Ansatz):Numerical realization (Test-Particle Ansatz):Initialization Propagation (Vlasov, collisions)

Initialization: „test particles“ initialized according to empirical density distributions

Problem: density profiles not consistent with mean-field used in propagationSolution: Use the same energy density functional ε[ρ p,ρ n] for initialization & propagation

Relativistic Thomas Fermi (RTF) for spherical nuclei

Old initialization

Old initialization

New initialization

New initialization

Important in calculating EImportant in calculating Eexcexc

Important in calculating A,Z Important in calculating A,Z

PR PR C81C81, (2010), , (2010), 054316

Münster, 23.03.11

GiBUU+SMM…GiBUU+SMM…Asymptotic equilibrated stageAsymptotic equilibrated stage

Statistical Multifragmentation Model (SMM)

Fission/spallation, evaporation, multifragmentation… (with increasing excitation)

Statistical determination of partial decay widths Monte-Carlo method

E*

Ai,Zi

E*-ε

Ad,Zd

j,ε

Ai Ad+n SMM code: Botvina & Mishustin, PR257(´95) 133SMM code: Botvina & Mishustin, PR257(´95) 133

* Non-Equilibrium dynamics within BUU until source(s) approaches stable configuration and local equilibration at t=tf* Determination of mass (A), charge (Z) and excitation energy Eexcitation energy Eexcexc of a source at time t=tf, then apply SMM

Hybrid GiBUU+SMM…Hybrid GiBUU+SMM…

Münster, 23.03.11

HypHI-project: C+C@2AGeV... HypHI-project: C+C@2AGeV...

SpectatorsSpectators

Well defined conditions after onset of instability…

SpectatorsSpectators

…and onset of equilibration

Def. ofSpectatorsDef. ofSpectators

Y(0)>0.75 +ρ>ρ sat/100

π

ΛΛ

ΛΛ

π

ΛΛ

ΛΛ

Σπ

πΚ

PL PL B663B663, 197 (08) & PL, 197 (08) & PLB675B675 (09) 297 (09) 297

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HypHI-project: Li+C@2AGeV... HypHI-project: Li+C@2AGeV... π

ΛΛ

ΛΛ

π

ΛΛ

ΛΛ

Σπ

πΚ

In preparation...

BUUBUU: fragmenting sources & strangeness (consistent with FOPI/KaoS)

SMMSMM: spectator fragmentation (consistent with ALADIN)

6Li-fragmentation12C-fragmentation

ΛΛ & & AAX coalescence X coalescence possiblepossible

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HypHI-project: Li+C@2AGeV... HypHI-project: Li+C@2AGeV... π

ΛΛ

ΛΛ

π

ΛΛ

ΛΛ

Σπ

πΚ

In preparation...

Coal.Coal.: momentum coalescence for Λ close to spectators

PredictionsPredictions: projectile/target fragmentation: σ (3HΛ, 4,5He

Λ) ~ (6-10)µb

Münster, 23.03.11

PANDA-subproject: PANDA-subproject: pp+X@(3-5)GeV... +X@(3-5)GeV...

In preparation...

(Why (Why pp-nucleus ?)-nucleus ?)

Residual sourceResidual source: minor differences

Particle yieldsParticle yields: huge differences

pΛ Λ

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fragmentation in p+X...(reminder)fragmentation in p+X...(reminder)

PL PL B663B663, 197 (08) & PL, 197 (08) & PLB675B675 (09) 297 (09) 297

datadataJ. Benlliure et al., Nucl. Phys. A683 (2001) 513.F. Rejmund et al., Nucl. Phys. A683 (2001) 540(Saclay) S. Leray et al., PRC65,044621

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...Charge distribution

Mass distribution…

In preparation...

PANDA-subproject: PANDA-subproject: pp+X@(3-5)GeV... +X@(3-5)GeV... (fragmentation)(fragmentation)p

Λ Λ

Münster, 23.03.11In preparation...

PANDA-subproject: PANDA-subproject: pp+X@(3-5)GeV... +X@(3-5)GeV... (fragmentation)(fragmentation)

EE** = Ep+(Mtarg-Btarg)Atarg-(Mres-Bres)Ares-Eem-Erec (energy balance event-by-event)

Good description of excitation spectrum

pΛ Λ

data: PRC63, 034616

Münster, 23.03.11In preparation...

PANDA-subproject: PANDA-subproject: pp+X@(3-5)GeV... +X@(3-5)GeV... (fragmentation)(fragmentation)

Overal good description of different fragment multiplicities

pΛ Λ

data: PRC63, 034616

Münster, 23.03.11In preparation...

PANDA-subproject: PANDA-subproject: pp+X@(3-5)GeV...+X@(3-5)GeV...(particle production)(particle production)p

Λ Λ

...rapidity spectra

Coalescence with stopped Λ's possible

No coalescence with Ξ's (in 2th target)

Strangeness production…

(consistent with data-> Larionov's talk)

Münster, 23.03.11In preparation...

PANDA-subproject: PANDA-subproject: pp+X@(3-5)GeV...+X@(3-5)GeV...(particle production)(particle production)p

Λ Λ

Coal.Coal.: momentum coalescence with captured Λ

...charge distributions

Production of single-Λ & double-Λ hypernuclei possible

Production of double-Λ hypernuclei via Ξ-capture in 2th target...

Münster, 23.03.11

Final remarks…Final remarks…

Theoretical studies: “FAIR” @ GiessenTheoretical studies: “FAIR” @ Giessen GiBUU+SMM: NE-dynamics + statistical process of fragmentationGiBUU+SMM: NE-dynamics + statistical process of fragmentation suitable tool for HypHI- & PANDA-reactionssuitable tool for HypHI- & PANDA-reactions

Benchmark tests (low energy)Benchmark tests (low energy) proper description of fragmentation process in p- & proper description of fragmentation process in p- & pp-reactions -reactions and in heavy-ion collisions and in heavy-ion collisions

First predictions on single-First predictions on single-ΛΛ hypernuclei (HypHI) hypernuclei (HypHI) σσ ~ ~ µµb for b for ΛΛH & H & ΛΛHeHe in spectator/target fragmentation in HIC in spectator/target fragmentation in HIC consistency with HypHI-experiment... (on work together with T. Saito)consistency with HypHI-experiment... (on work together with T. Saito)

First predictions on double-First predictions on double-ΛΛ hypernuclei (PANDA) hypernuclei (PANDA) multiply coalescence of captured multiply coalescence of captured ΛΛ's already in first target's already in first target ΞΞ's escape, might need 2th target...(on work)'s escape, might need 2th target...(on work)

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Backup slides

Münster, 23.03.11

Pre-Equilibrium (GiBUU): high-energy n-emission, QE-peakAsymptotic final state (SMM): Statistical decay of excited sourceFinal Result: Hybrid GiBUU+SMMFinal Result: Hybrid GiBUU+SMM

data: S. Leray et al., PRC65,044621

neutrons

Application-I: Fragmentation in p+X@0.8 GeV Application-I: Fragmentation in p+X@0.8 GeV (energy spectra…)(energy spectra…)

Prog. Part. Nucl. Phys. (2009), in pressProg. Part. Nucl. Phys. (2009), in press (arXiv:0811.3506)(arXiv:0811.3506)

Münster, 23.03.11

Applications-II: Fragmentation in X+X reactionsApplications-II: Fragmentation in X+X reactions

absolute yieldsabsolute yields from spectator fragmentation in

Au+Au@0.6AGeV

(ALADIN-data)

fragment velocity spectrafragment velocity spectra

in Xe+Pb@1.0AGeV

data:Henzlova, PRC78, 044616

Münster, 23.03.11

Applications-II: Hypernuclei in spectator fragmentation…Applications-II: Hypernuclei in spectator fragmentation…(HypHI, (HypHI, 1212C+C+1212C@2AGeV)C@2AGeV)

First transport theoretical predictions: total yields ~µbConsistent with previous studies: M.Wakai, NPA547(92)89cM.Wakai, NPA547(92)89c

Prog. Part. Nucl. Phys. (2009), in press Prog. Part. Nucl. Phys. (2009), in press (arXiv:0811.3506)(arXiv:0811.3506)

Phys. Lett. B (2008), submittedPhys. Lett. B (2008), submitted

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Applications-II: Hypernuclei from high energy proton-induced reactions…Applications-II: Hypernuclei from high energy proton-induced reactions…(PANDA/J-PARC, p+(PANDA/J-PARC, p+1212C@50GeV)C@50GeV)

Two sources (residual target+moving source)

Most of hyperons created & rescatter inside moving source

Prog. Part. Nucl. Phys. (2009), in press (arXiv:0811.3506), Phys. Lett. B (2008), submittedProg. Part. Nucl. Phys. (2009), in press (arXiv:0811.3506), Phys. Lett. B (2008), submitted

Münster, 23.03.11

Prog. Part. Nucl. Phys. (2009), in pressProg. Part. Nucl. Phys. (2009), in press

Phys. Lett. B (2008), submittedPhys. Lett. B (2008), submitted

Getting started: Spectator fragmentation at Au+Au@0.6 GeVGetting started: Spectator fragmentation at Au+Au@0.6 GeV

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New initialization: Binding energy & rms-radius in BUU…New initialization: Binding energy & rms-radius in BUU…

Old initialization

Old initialization

new initialization

new initialization

RTF-binding energy

Münster, 23.03.11

Mean-field vs cascade – the role of the mean-field…Mean-field vs cascade – the role of the mean-field…

(PANDA/J-PARC, p+(PANDA/J-PARC, p+1212C@50GeV)C@50GeV)

central

peripheral

Münster, 23.03.11

Ground state in BUU-II: Ground state in BUU-II: Results (application to proton-induced reactions)Results (application to proton-induced reactions)

Formation of hypernuclei in reactions induced by heavy-ion and hadron beams Slide 2Relativistic hypernuclei…Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Conclusions…Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26