evidence of nuclear rainbow in the 27al + 16o elastic ... of nuclear rainbow in the 27al + 16o...
TRANSCRIPT
R. Linares 19 – 06 – 2015
Evidence of Nuclear rainbow inEvidence of Nuclear rainbow in
the the 2727Al + Al + 1616O elastic scattering O elastic scattering
@ 280 MeV@ 280 MeV
Roberto LinaresUniversidade Federal Fluminense, Niteroi – BR
R. Linares 19 – 06 – 2015
Towards an universal Towards an universal imaginary potentialimaginary potentialPLB 670 (2009) 330-335
Imaginary potential for tightly bound systems that takes into account
Deep inelastic
Break-up
Starting point: the same shape of the real part
Normalization factor based on the Glauber model
R. Linares 19 – 06 – 2015
Towards a universal Towards a universal imaginary potentialimaginary potential
U (R)=V (R)+iW (R )
V (R , E)=V spp (R)e−4 ( v(r )
c )2
W (R ,E)=0.6×V (R , E)
Fig.
3 fro
m P
ereir
a D.
et a
l., P
hys.
L ett.
B 670
(330
) 200
9
Explicity couplings to inelastic and transfer channels
R. Linares 19 – 06 – 2015
Case of study: Case of study: 1616O + O + 2727AlAl
U (R)=V (R)+iW (R )
V (R , E)=V spp (R)e−4 ( v(r )
c )2
W (R ,E)=0.6×V (R , E)
Fig.
6 fro
m P
ereir
a D.
et a
l., P
hys.
L ett.
B 670
(330
) 200
9
Good agreement with available experimental data
up to ~200MeV
R. Linares 19 – 06 – 2015
Predictions for Predictions for 1616O+O+2727AlAl
Nuclear rainbow???
R. Linares 19 – 06 – 2015
The nuclear rainbowThe nuclear rainbow
nucleus-nucleus scatteringdisplay rainbow features
• Elastic channel• Small absorption
• 4He elastic scattering
• 16O + 16O
• 12C + 12C
Goldberg D. A. et al., Phys. Rev. C 10(1362) 1974Goldberg D. A. et al., Phys. Lett. 29(500) 1972
Goldberg D. A. et al., Phys. Rev. C 7(1938) 1973
Stokstad R. G. et al., Phys. Rev. C 20(655) 1976Bohlen H. G. et al., Z. Phys. A 308(121) 1982Bohlen H. G. et al., Z. Phys. A 322(241) 1985
Stiliaris E. et al., Phys. Lett. B 223(291) 1989
Bartnitzky G. et al., Phys. Lett. B 365(23) 1996Bohlen H. G. et al., Z. Phys. A 346(189) 1993
R. Linares 19 – 06 – 2015
1616O+O+2727Al (@ 100MeV): Al (@ 100MeV): experimental dataexperimental dataMeasurement performed @ 100MeV with MAGNEX Spectrometer (INFN-LNS)
Coupling to inelastic state: Si28(2+ .
)×(1d5/2)−1
R. Linares 19 – 06 – 2015
1616O+O+2727Al (@ 100MeV): Al (@ 100MeV): experimental dataexperimental dataMeasurement performed @ 100MeV with MAGNEX Spectrometer (INFN-LNS)
Coupling to inelastic state: Si28(2+ .
)×(1d5/2)−1
Coupling to inelastic channel plays a crucial
role for the nuclear rainbow
R. Linares 19 – 06 – 2015
Recent works...Recent works...
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Unexpected rainbow: Unexpected rainbow: what next?what next?
A challeging measurement
✔ Energy resolution and accuracy
✔ Angular resolution
✔ Good signal-noise ratio
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Energy resolutionEnergy resolution
FWHM: 450 keVFWHM: 450 keV
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Giant ResonancesGiant Resonances
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Angular Distribution Angular Distribution @280 MeV@280 MeV
Elastic and inelastic channels in opposite phase.
R. Linares 19 – 06 – 2015
Angular Distribution Angular Distribution @280 MeV@280 MeV
Elastic and inelastic channels in opposite phase.
Possible Airy minima at 41°
R. Linares 19 – 06 – 2015
Angular Distribution Angular Distribution @280 MeV@280 MeV
Elastic and inelastic channels in opposite phase.
Possible Airy minima at 41°
However calculations are higher
R. Linares 19 – 06 – 2015
CC CalculationsCC Calculations
Reasonableagreement with
experimental data
R. Linares 19 – 06 – 2015
CC CalculationsCC Calculations
...and indeedreproduces fairly
well inelasticdistributions
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OutlookOutlook
✔ Angular distribution of elastic and inelastic states.
✔ Evidence of nuclear rainbow feature in the elastic channel of 16O + 27Al @ 280MeV.
✔ Giant resonances were observed.
✔ CC calculations reproduce both elastic and inelastic angular distributions when real potential is supressed.