Exotic Shapes and High Spin physics with Intense Stable Beams

Shell structure far from spherical magic numbers

Which is the adopted deformation and how it changes with spin andenergy ?

What are the active orbitals and their correlations ?

How is spin generated ?

How much spin can the nucleus sustain ?

Superdeformed world = more than 250 SD rotational bands

Octupole vibrationsGyromagnetic factors

Triaxial bands + wobbling

Band termination

Particle decay

Large Shell Model calculations

SD bindingenergies

Jacobi shape transition

Rotational damping

Hyperdeformation

ChaosAssistedtunneling

superdeformation

fission

SPIN

ENERGY GDR

Tetrahedralnuclei

A domain rich of new exotic phenomena to be discovered and studied

HIGH L

HLHD ExperimentEUROBALL: 64Ni + 64Ni

• 261 MeV: 52 keV ridge appears

4 x 52 keVInt.: 993

Int.: 1367

Ridge intensity ~5 x 10-5

Search for discrete-line HD spectraEuroball, E ~ 52 keV

A strange feeling of ‘déjà vu’

Triaxiality and

Wobbling TSD4

TSD1TSD2

TSD3

Relative population

TSD1: 10% TSD2: 3% TSD3: 1.2% TSD4: 0.9%

Experimental results in

163LuThe best

”Wobbler”

D.R. Jensen et al., Phys. Rev. Lett. 89 (2002), 142503.

0 10 20 30 400.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

1.2fis

sion

sphe

rical

prol

ate

tria

xial

obla

te

1.00.80.6

0.40.0

2

R L/R S

I []

I=27

0.00

0.04

0.08

0.12

0.16

0.20

0.24

0.28

0 5 10 15 20 25 30 35

E [MeV]

I=0

0.00

0.04

0.08

0.12

0.16

0.20

0.24

0.28

0 5 10 15 20 25 30 35

E [MeV]

I=25

0.00

0.04

0.08

0.12

0.16

0.20

0.24

0.28

0 5 10 15 20 25 30 35

E [MeV]

I=34

0.00

0.04

0.08

0.12

0.16

0.20

0.24

0.28

0 5 10 15 20 25 30 35E [MeV]

I=0

I=25

I=27

I=34

Looking for Jacoby shape transition

spin

Oblate Prolate

0 5 10 15 20 25 30 35

Y [a

. u.]

E [MeV]

Exp. LSD (I = 28-34) LSD (I = 24)with Coriolis

Gates:

Time of FlightResidues nuclei (42Ca)Low energy multiplicity

Theory: (Jacoby shape transition)LSD model + Coriolis Splitting

A. Maj et al. Nucl. Phys. A731 (2004) 319

Fusion evaporation reactions

Ibeam ~ 10 - 10 p/s

Limitation: counting rate in theGermanium detectors and/orcommon acquisition dead-time

10 11

Resolving power ~ 10 -4

Limitation: current arrays

(5-10 pnA)

High spin states populated in

Fighting to observe VERY WEAK signals…

Gamma-ray Detector Development

• Advances in detector technology have resulted in new discoveries.

• Innovations have improved detector performance.– Energy resolution– Efficiency– Peak-to-total ratio– Position resolution– Directional information– Polarization– Auxiliary detectors

• Tracking is feasible, will provide new opportunities and meet the challenges of new facilities.

Central Role in Nuclear Physics

high granularity+

digital electronics

AGATA will be able to handle

10 – 100 times more beamAdvanced GAmma Tracking Array

Nevt = Np x Nt x x d