Fragment formation in low energy proton-induced reactions within a hybrid BUU+SMM approach

DPG, 11.03.08

Fragment formation in low energy proton-induced reactions Fragment formation in low energy proton-induced reactions within a hybrid BUU+SMM approachwithin a hybrid BUU+SMM approach

Th. Gaitanos, H. Lenske, U. MoselTh. Gaitanos, H. Lenske, U. Mosel

IntroductionIntroduction

Theoretical descriptionTheoretical descriptionNon-equlibrium stage (GiBUU)Asymptotic equilibrium stage (SMM)Hybrid approach (GiBUU+SMM)

ApplicationsBenchmark p+X@SIS/GSI energies

Final remarksFinal remarks

DPG, 11.03.08

Introduction…Introduction…Introduction…Introduction…

Spallation reactions („small“ excitation of residual nucleus resp. to its ground state)

useful tool to theoretically study/test long-time scales of fragmentation process

Spallation reactions („small“ excitation of residual nucleus resp. to its ground state)

useful tool to theoretically study/test long-time scales of fragmentation process

ApplicationsApplications

•Study of hypernuclei (2nd talk): HIC@SIS (HypHI)

•In future: PANDA (pbar+X), J-PARC (p+X@50GeV, X+X@20AGeV)

ApplicationsApplications

•Study of hypernuclei (2nd talk): HIC@SIS (HypHI)

•In future: PANDA (pbar+X), J-PARC (p+X@50GeV, X+X@20AGeV)

Theor. description of Low energy hadron-induced Theor. description of Low energy hadron-induced reactionsreactions

Theor. description of Low energy hadron-induced Theor. description of Low energy hadron-induced reactionsreactions

Non-(pre-)equilibrium first phaseNon-(pre-)equilibrium first phaseNon-(pre-)equilibrium first phaseNon-(pre-)equilibrium first phase Asymptotic final stateAsymptotic final stateAsymptotic final stateAsymptotic final state

Equilibrated source with small excitation

Statistical multifragmentation models

Equilibrated source with small excitation

Statistical multifragmentation models

Highly excited system

Dynamical transport (BUU, QMD, INC)

Highly excited system

Dynamical transport (BUU, QMD, INC)

„„Hybrid“ models Hybrid“ models (BUU+SMM)(BUU+SMM)

DPG, 11.03.08

Theoretical description…Theoretical description…Theoretical description…Theoretical description…

Initial non-equilibrium stageInitial non-equilibrium stage

•Relativistic transport equation of Boltzmann-type

•Giessen-Boltzmann-Uehling-Uhlenbeck (GiBUU)

Initial non-equilibrium stageInitial non-equilibrium stage

•Relativistic transport equation of Boltzmann-type

•Giessen-Boltzmann-Uehling-Uhlenbeck (GiBUU)

Asymptotic equilibrated stageAsymptotic equilibrated stage

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

•Statistical determination of partial decay widths Monte-Carlo method

(basic method similar to numerical treatment of collisions in transport approaches)

Asymptotic equilibrated stageAsymptotic equilibrated stage

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

•Statistical determination of partial decay widths Monte-Carlo method

(basic method similar to numerical treatment of collisions in transport approaches)

E*

Ai,Zi

E*

Ai,Zi

E*-

Ad,Zd

E*-

Ad,Zd

j,j,

AiAi Ad+nAd+n

(http://theorie.physik.uni-giessen.de/GiBUU)(http://theorie.physik.uni-giessen.de/GiBUU)(http://theorie.physik.uni-giessen.de/GiBUU)(http://theorie.physik.uni-giessen.de/GiBUU)

SMM code: Botvina & Mishustin, PR257(´95) SMM code: Botvina & Mishustin, PR257(´95) 133133SMM code: Botvina & Mishustin, PR257(´95) SMM code: Botvina & Mishustin, PR257(´95) 133133

DPG, 11.03.08

Benchmark: Benchmark: [email protected][email protected] (properties of fragmenting source)… (properties of fragmenting source)…Benchmark: Benchmark: [email protected][email protected] (properties of fragmenting source)… (properties of fragmenting source)…

e-Print: arXiv: 0712.3292 (almost accepted…)e-Print: arXiv: 0712.3292 (almost accepted…)e-Print: arXiv: 0712.3292 (almost accepted…)e-Print: arXiv: 0712.3292 (almost accepted…)

Definition of residual nucleus: <sat/100.Definition of residual nucleus: <sat/100.

Non-Equilibrium dynamics within GiBUU until system(s) approach local equilibrium at t=tf

Determination of A,Z and Eexc at time tf, and then apply SMM

Non-Equilibrium dynamics within GiBUU until system(s) approach local equilibrium at t=tf


DPG, 11.03.08

Benchmark: Benchmark: [email protected][email protected] (global characteristics)… (global characteristics)…Benchmark: Benchmark: [email protected][email protected] (global characteristics)… (global characteristics)…

Charge distribution…Charge distribution…

Mass distribution…

Mass distribution…

e-Print: arXiv: 0712.3292 (almost accepted…)e-Print: arXiv: 0712.3292 (almost accepted…)

Data: F. Rejmund et. al., NPA683(´01) 540Data: F. Rejmund et. al., NPA683(´01) 540

J. Benlliure et. al., NPA683(´01) 513J. Benlliure et. al., NPA683(´01) 513




DPG, 11.03.08

Benchmark: Benchmark: p+Xp+X reactions (details)… reactions (details)…Benchmark: Benchmark: p+Xp+X reactions (details)… reactions (details)…







DPG, 11.03.08

Final remarks & Outlook…Final remarks & Outlook…

Low-energy proton-induced reactionsLow-energy proton-induced reactions Residual system under stable conditions no compression/expansion effects, no radial flow effects Wide selection of experimental data Useful tool to study transport models including fragmentation

Hybrid approach (GiBUU+SMM)Hybrid approach (GiBUU+SMM) Initial stage: StableStable ground state pre-equilibrium dynamics: relativistic GiBUU asymptotic equilibrated stage: statistical decay by means of SMM

Comparison with a wide selection of exp. data Comparison with a wide selection of exp. data Global characteristics and details fairly well reproduced

Future/under progress developmentsFuture/under progress developments Gradient terms in meson field equations (A.Larionov) Extended for iso-vector degrees of freedom (-meson) More consistent treatment of ground state (RTF)

DPG, 11.03.08

Ground state in BUU: Stability…Ground state in BUU: Stability…Ground state in BUU: Stability…Ground state in BUU: Stability…

Important in calculating EImportant in calculating Eexcexc

Energy must be conserved!

Important in calculating EImportant in calculating Eexcexc

Energy must be conserved!

Important in determing the Important in determing the sourcesource

No spurious particle emission!

Important in determing the Important in determing the sourcesource

No spurious particle emission!

Improved model for ground state simulations in BUU

B. Steimüller, O. Buss, U. Mosel, poster session, HK34.87

Improved model for ground state simulations in BUU

B. Steimüller, O. Buss, U. Mosel, poster session, HK34.87

DPG, 11.03.08

Dynamical aspects in Dynamical aspects in p+Xp+X reactions… reactions…Dynamical aspects in Dynamical aspects in p+Xp+X reactions… reactions…

Definition of residual nucleus: <sat/100.Definition of residual nucleus: <sat/100.

Combination: BUU+SMM (hybrid model)…Combination: BUU+SMM (hybrid model)…Combination: BUU+SMM (hybrid model)…Combination: BUU+SMM (hybrid model)…

Non-Equilibrium dynamics within BUU until system(s) approach local equilibrium at t=tf


Non-Equilibrium dynamics within BUU until system(s) approach local equilibrium at t=tf


Fragment formation in low energy proton-induced reactions within a hybrid BUU+SMM approach

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