nuclear reactions studies in spain (theory) · nuclear reactions at seville (theory) 1)...

Nuclear reactions studies in SpainNuclear reactions studies in Spain(theory) (theory)

Antonio M. Moro Muñoz

Universidad de Sevilla

Outline:

● Current groups working in nuclear reactions● A flavour on recent research activities

✔ Developments in nuclear reaction theory✔ Collaborations with experimental groups

● Challenges for the near future

USE

UHU USE

Madrid

Nuclear Reactions in Spain

Theory:- Madrid (IEM, UCM)- Huelva (UHU)- Sevilla (USE)

Santiago

Valencia Experiments:- Madrid (IEM)- Huelva- Santiago de Comp. - Sevilla (USE/CNA)- Valencia

Nuclear Reactions at Madrid (IEM/CSIC, UCM) Nuclear Reactions at Madrid (IEM/CSIC, UCM)

Few-body structure and reactions:• Bound and continuum states of three-body light nuclei (11Li, 12Be,...)

• Few-body reactions at low energies of astrophysical interest (α+α+α → 12C, α+α+n → 9Be)

• Variational description of continuum states in terms of integral relations.

(E. Garrido, R. Álvarez-Rodríguez, R. de Diego (*), C. Redondo(*)

8Be is unbound8Be is unboundAfter the core collapse, the

temperature increases, and for T ~ 108 K …

After the core collapse, the temperature increases, and for

T ~ 108 K …

...the triple-alpha reaction is relevant !!!...the triple-alpha reaction is relevant !!!

The triple-alpha reaction bridges the A=5,8 gap and permits the appearance in the Universe of heavy nuclei

The triple-alpha reaction bridges the A=5,8 gap and permits the appearance in the Universe of heavy nuclei

Direct versus sequential capture mechanism

1) Sequential: α + α → 8Be* + γ

8Be* +α → 12C2) Direct : α + α+α → 12C + γ

1) Sequential: α + α → 8Be* + γ

8Be* +α → 12C2) Direct : α + α+α → 12C + γ

A direct capture mechanism can

increase the reaction rate up to 7

orders of magnitude at low

temperatures.

A direct capture mechanism can

increase the reaction rate up to 7

orders of magnitude at low

temperatures.

3-body problem → Faddeev equations

Nuclear Reactions at Seville (theory)

1) Developments in nuclear reaction theory➔ Dispersive Lane-consistent optical potentials➔ Resonant & non-resonant 2- and 3-body continuum of exotic nuclei➔ Extension of CDCC method to 3-body nuclei and core excitation➔ Two-particle transfer reactions

2) Theory support to experimental collaborations➔ Sevilla-IEM-Huelva collaboration (CNA,TRIUMF, LLN, GANIL...)➔ ISOLDE ➔ RIBRAS, ➔ etc

(M.V. Andrés, J.M. Arias, F. Barranco, J. Casal-Berbel (PhD),C. Dasso, J. Gómez-Camacho, J.A. Lay (PhD), A.M. Moro, G. Potel (*) J.M. Quesada, M. Rodríguez-Gallardo)

A Lane consistent optical model potential for nucleon induced reactions on actinides with full coupling

J. M. Quesada, Departamento de FAMN, Seville

Roberto Capote, IAEA Nuclear Data Section, ViennaEfrem Soukhovitskii, Joint Institute for Energy and Nuclear Research, Minsk-Sosny, Belarus

Global fitting to the available exp. db:total xs, angular distributions, strenght functions..

+..+Phenomenological potential with strong theoretical constraints : less parameters and enhanced predictability

The coupling scheme includes:All states bellow 1 MeV (17 for 238U) + 2 IAS states

Included in RIPL: entries 2408, 2409, 5408, 5409, 5412

Used in nuclear data evaluations

Tries 2408,5

Microscopic calculations of two-nucleon transfer(P. Barranco (USE), G. Potel (USE), R. Broglia (Milan))

Information on:● Pairing correlations● Reaction mechanism (sequential vs simultaneous)● Two-particle spec. factors

Information on:● Pairing correlations● Reaction mechanism (sequential vs simultaneous)● Two-particle spec. factors

Inclusion of core excitation in the scattering of

two-body halo nuclei with deformed core.

Inclusion of core excitation in the scattering of

two-body halo nuclei with deformed core.

Scattering of 3-body (eg Borromean) nuclei require:➔3-body description of the projectile➔Four-body scattering framework (4b-CDCC)

Scattering of 3-body (eg Borromean) nuclei require:➔3-body description of the projectile➔Four-body scattering framework (4b-CDCC)

Extensions of the CDCC method

Collaboration with experimental groups

➢ Sevilla-Madrid-Huelva collaboration: scattering of exotic nuclei in international RNB facilities (Louvain-la-Neuve, ISOLDE/CERN, TRIUMF, GANIL)

➢ REX-ISOLDE (CERN):Low energy reactions with radioactive beams

➢ RIBRAS (Sao Paulo, Brasil)➢ Notre Dame (USA)

➢ Sevilla-Madrid-Huelva collaboration: scattering of exotic nuclei in international RNB facilities (Louvain-la-Neuve, ISOLDE/CERN, TRIUMF, GANIL)

➢ REX-ISOLDE (CERN):Low energy reactions with radioactive beams

➢ RIBRAS (Sao Paulo, Brasil)➢ Notre Dame (USA)

Study of 6He,11Li+208Pb (Sevilla-Huelva-Madrid collaboration)

Strong Coulomb dipole polarizability effect predicted in 11Li+208Pb elastic scattering (Andrés et al, '96)

6He+208Pb experiments performed at Louvain-la-Neuve (2002,2004) 2 PhD theses →

- Development of 4-body CDCC method (1 PhD thesis)- Development of transfer-to-the continuum method (α's) (1 PhD)

11Li+208Pb elastic scattering: the largest deviation from Rutherford formula ever observed

- 11Li very weakly-bound (S2n=370 KeV)- 11Li structure strongly distorted by the electric field of a heavy target- 11Li fragments accompanied by large yield of 9Li (breakup)

- 11Li very weakly-bound (S2n=370 KeV)- 11Li structure strongly distorted by the electric field of a heavy target- 11Li fragments accompanied by large yield of 9Li (breakup)

10Li spectroscopy from 2H(9Li,p)10Li transfer reaction (IS367 experiment).

➔ Unbound exotic nuclei can be studied via transfer reactions.➔ Extensions of the DWBA approach for unbound final states developed and applied to 9Li(d,p)10Li (ISOLDE)➔ Spectroscopic information: resonances, virtual states

➔ Unbound exotic nuclei can be studied via transfer reactions.➔ Extensions of the DWBA approach for unbound final states developed and applied to 9Li(d,p)10Li (ISOLDE)➔ Spectroscopic information: resonances, virtual states

Challenges for near future

A new generation of experiments is demanding the calculation of new observables

➢ Three-particle correlations in breakup experiments➢ (p,2p), (p,pn) knock-out reactions in complete

kinematics ➢ Quasi-free scattering➢ Etc

A new generation of experiments is demanding the calculation of new observables

➢ Three-particle correlations in breakup experiments➢ (p,2p), (p,pn) knock-out reactions in complete

kinematics ➢ Quasi-free scattering➢ Etc

Interpretation of fragmentation experiments involving coincidence measurements of outgoing fragments.

➢ Leading facilities (eg. GANIL) are starting to measure correlations between fragments produced after breakup.

➢ Requires the development of appropriate formalisms to calculate these observables from our four-body CDCC calculations.n-n correlations after 6He breakup

Collaborations

Instituto Superior Técnico (Lisbon, Portugal)

University of Lisbon (Lisbon, Portugal)

Michigan State University (USA)

Surrey University (UK)

Warsaw University (Poland)

Aarhus University (Denmark)

University of Milan.

University of Orsay (France)

Padova University (Italy)

INFN Division of Catania

Univ. Sevilla (CNA)

University of Huelva (Spain)

Instituto de Estructura de la Materia (CSIC, Madrid)

Göteborg University (Sweden)

Andrzej Soltan Institute for Nuclear Studies (Poland)

University of Orsay (France)

GANIL

Aarhus University (Denmark)

University of Sao Paulo (Brasil)

TRIUMF

THEORY EXPERIMENTS

NuPECC Long Range Plan 2010: “Perspectives of Nuclear Physics in Europe”

“New project for advanced studies in theoretical nuclear structure and reaction physics of exotic nuclei bringing together theorists, computer scientists and experimentalists to support and stimulate experimental research performed at the European facilities”

Thanks for your attention!Thanks for your attention!

Solve the Faddeev Equations in coordinate space.

Hypersherical harmonic adiabatic expansion method.

Continuum discretization with a box boundary condition.

Study of 6He+208Pb within the Sevilla-Huelva-Madrid collaboration

✔ Angular and energy distribution of α particles consistent with 2n-neutron transfer mechanism to unbound states of the target

Application of TC method to the inclusive reaction 6He + 208Pb at Coulomb barrier energies (PH189)

Interplay between core and valence excitation in scattering of halo nuclei

- halo nuclei loosely bound particle favours halo excitation → →(single-particle) mechanism- However, if the remaining nucleus is deformed collective excitations of the core may also contribute → Core excitation

- halo nuclei loosely bound particle favours halo excitation → →(single-particle) mechanism- However, if the remaining nucleus is deformed collective excitations of the core may also contribute → Core excitation

Core excitation in 11Be breakup

Interpretation of fragmentation experiments involving coincidence measurements of outgoing fragments.

New generation of experiments at leading facilities (eg. GANIL) are starting to measure correlations between fragments produced after breakup of Borromean nuclei.

These experiments will provide useful information on correlations of the original nucleus.

We plan to develop the appropriate formalisms to calculate these observables starting from our four-body CDCC calculations.

Application of the 3-body discretization method to interpret measured elastic data.

✔ We have implemented our THO discretization method into a Coupled Channels reaction formalism to interpret the elastic data → Four-body CDCC calculation! ✔ Inclusion of 3-body continuum states essential to describe the data.

✔ Borromean nuclei, such as 6He or 11Li, require a 3-body description of the bound and unbound states.

✔ We have developed two discretization methods to describe the 3-body continuum:

● “Transformed harmonic oscillator” (THO) method

● Binning method

Extension of THO method to 3-body projectiles

- Ph.D thesis of Manuela Rodríguez Gallardo (U. Sevilla, 2005)- PRC77, 064609 (2008)

10Li spectroscopy from 9Li(d,p)10Li transfer reaction (IS367 experiment).

00

✔ Experiment performed at REX-ISOLDE (CERN) by the ISOLDE collaboration to study the properties of 10Li continuum.

Participation in experimental programs

● DINEX (Sevilla-Huelva-Madrid): scattering of exotic nuclei in international RIB facilities (Louvain-la-Neuve, ISOLDE/CERN, TRIUMF)

● REX-ISOLDE: Low energy reactions with radioactive beams

● GANIL-SPIRAL2: LOI “Unbound states of neutron-rich isotopes via direct reactions”

● RIBRAS (Sao Paulo)

2) Applications of these formalisms to the understanding and interpretation of experimental results

● Theoretical support to CNA activities at Seville.

● Extract global properties of nucleus-nucleus interaction from the

analysis of elastic, transfer and breakup experiments performed in

RNB facilities (GANIL, TRIUMF, ISOLDE, Sao Paulo).

● Extraction of spectroscopic information from transfer and

breakup experiments (eg. ISOLDE/CERN)

● Physic cases for future experiments to be performed at the new

European facilities (GANIL/SPIRAL2, GSI/FAIR).

➢ Borromean nuclei, such as 6He or 11Li, require a 3-body description of the bound and unbound states.

➢ We have developed two methods to discretize the 3-body continuum:

➢ “Transformed harmonic oscillator” (THO) method

➢ Binning method

Reactions with three-body weakly bound projectiles




➢ Binning method


Analysis of transfer/breakup reactions: the transfer to the continuum method

✔ Fragmentation processes are sometimes better described using a “transfer to the continuum” picture, rather than an inelastic-like process (“direct breakup” picture).

✔ We have developed a “transfer to the continuum” formalism combining the CDCC discretization method with the CCBA reaction mechanism.

F.M. Nunes and A.M. Moro, NPA767, 138 (2006)

Main objectives of the project

1) Development of structure and reaction formalisms appropriate for exotic nuclei.

2) Applications of these formalisms to the understanding and interpretation of experiments. Collaboration with experimental groups.

The nuclear landscape




➢ Binning method


1) Development of structure and reaction formalisms appropriate for exotic nuclei.

● Description of the structure of exotic nuclei: bound and unbound states.

Eg: Borromean systems (6He, 11Li, 14Be, etc)

● Effect of the continuum in scattering observables.

● Calculation of correlations between fragments following breakup.

● Application of Faddeev-AGS equations to the scattering of light exotic

nuclei.

● Treatment of two-neutron transfer in reactions induced by Borromean

nuclei.

● Collective excitations.

We plan to keep a close collaboration with experimental groups to provide theoretical support in the interpretation of their measurements:

✔ REX-ISOLDE (CERN)● 11Be+p● 8Li+p

✔ GANIL● 11Li+p● 8He+208Pb (approved)

✔ RIBRAS (Sao Paulo)● 6He + 120Sn, 6He+ 27Al● 8Li + 12C

✔ TRIUMF● 11Li + 208Pb, 11Li+p

Theoretical support to experimental collaborations

These experiments have been already performed,and the theoretical analysis is under our responsibility.

We plan to keep a close collaboration with experimental groups to provide theoretical support in the interpretation of their measurements:

✔ REX-ISOLDE (CERN)● 11Be+p (IS430) K. Riisager, H. Jeppesen (2005)● 8Li+p

✔ GANIL● 11Li+p● 8He+208Pb (approved)

✔ RIBRAS (Sao Paulo)● 6He + 120Sn, 6He+ 27Al● 8Li + 12C

✔ TRIUMF● 11Li + 208Pb, 11Li+p

Theoretical support to experimental collaborations

Example: 11Li+208Pb reaction @ TRIUMF (2008)(Sevilla-Madrid-Huelva-Chalmers collaboration)

11Li

9Li

Semiclassical and CDCC calculations suggest a direct breakup mechanism

What is the mechanism producing 9Li?

First applications of Faddeev equations to nuclear reactions with weakly bound nuclei

✔ Collaboration with nuclear physics group at Lisbon University

nuclear reactions studies in spain (theory) · nuclear reactions at seville (theory) 1)...

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