antiprotons for nuclear structure investigations
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Antiprotons for Nuclear Structure Investigations. H. Lenske Institut für Theoretische Physik, U. Giessen. Measuring Neutron Skins on Isotopic Chains (Ni,Sn…): p + A Absorption@FAIR: the AIC Proposal. - PowerPoint PPT PresentationTRANSCRIPT
Antiprotons for Nuclear Structure Investigations
H. Lenske Institut für Theoretische Physik, U. Giessen
Measuring Neutron Skins on Isotopic Chains (Ni,Sn…):
p + A Absorption@FAIR: the AIC Proposal
P. Kienle, NMB 214 (2004) and AIC@FAIR
Proposal
H.L., P. Kienle, Phys.Lett. B647 (2007) 82-87
Antiprotons for Nuclear Structure Investigations @FAIR
Agenda:
Antiproton-N and Antiproton-Nucleus Antiproton-N and Antiproton-Nucleus InteractionsInteractions
Nuclear Radii from Absorption Cross SectionsNuclear Radii from Absorption Cross Sections Antiprotons and Neutron-SkinsAntiprotons and Neutron-Skins Screening Effects in Neutron-rich NucleiScreening Effects in Neutron-rich Nuclei Isospin Tagging by Pion ProductionIsospin Tagging by Pion Production Strangeness ProductionStrangeness Production OutlookOutlook
The antiproton-proton Interaction: LEAR Data
p p
p p
Antiproton-Nucleon Interactions
KK
p p
...
- 0
0
K K
n p
...
The History of the longterm relation…
…of antiprotons and nuclei:
• anti-protonic atoms and tails of nuclear densities
• antiproton-A elastic scattering
• annihilation and pion production
• G-parity transformation of scalar and vector self-energies deep potentials ~ -500 MeV
• dispersive self-energies from annihilation channels
• Annihilation and Quark Models
• Meson & Hadron Dynamics from pphh
Consequences of G-Parity in Nuclear Binding
Energy Deposition in a Nucleus
(Cascade-Calculations, Clover et al., PRC 26)
p p (at rest)
The antiproton-Nucleus Interaction
Antiproton+A scattering:
• Free Space pN T-Matrix
• Nuclear Structure: state-of-the-art HFB p and n Densities
• optical Potential in Impulse (t) Approximation
Antiproton+Nucleus Interactions:Elastic Scattering
pA Scattering: Optical Potential and Absorption Cross
Section From The Continuity
Equation:
3 ( )† ( )abs s s opt s2
2m 1tr d r r, k (U ) r, k
2s 1k
s2 (z,b)2abs s opt2
2m 1tr d bdz (U (r))e
2s 1k
Eikonal Approximation:
Antiproton Absorption on 58,78Ni: The Monopole Annihilation Kernel and the
Nuclear Density
( ) 2s
1 1ˆ(r, k) dr | (r, k) |
2s 1 4
Antiproton+A Absorption: Limiting Cases
Probing Nuclear Radii by Antiprotons
• scaling of abs ~ <r2>
• energy independent slope
• convergence of magnitude
• from proton to neutron skin
• increasing <r2>
• neutron skins up to 0.6 fm
• charge radii by e- scattering
Measuring Neutron Skins on Isotopic Chains (Ni,Sn…):
p + A Absorption on protons and neutrons
H.L., P. Kienle, Phys.Lett. B647 (2007) 82-87
Localization of the Annihilation Process
2
dP(b) (b)
bdb
bk ( 1)
Spatial Localization of Antiproton
Annihilation on a Nucleus:
Peripheral Process
Cascade Results by Clover et al., PRC 26
Absorption on Protons
b=4fm
Absorption on Neutrons
b=4fm
Shielding of Target Protons by the Neutron Skin
protons
neutrons
Tlab=700 MeV
Antiproton Annihilation on Ni-Isotopes: Scaling of abs
Antiproton+N Absorption: Isospin Symmetry
ppnp
ppnp
Antiproton+Nucleus Interactions: Isospin Symmetry
...)()()(
)()()(~)(
2
20
rrkt
rrktrU
pnF
pnFAp
Enhanced along isotopic chains!
p A(N,Z) C(N 1,Z) k
0p A(N,Z) B(N,Z 1) k n
Peripheral Antiproton Annihilation on a Nucleus:
Pion Production:
Differential Coherent Antiproton Annihilation on a Nucleus:
k kk
0
...
KK ...Np a hh
YY ...
... (N=n)
( )*3 3 ( )pN n nM (k ,k ) d r d r (k , r ) t (x) (r ) (k , r )
i(k r k r ) 2 (r , r )3 3pN n nM (k ,k ) ~ d r d r e t (x) (r )e
Differential Antiproton Annihilation on a Nucleus:
Eikonal Approximation:
Quantum Mechanical Amplitude:
LEAR-Data (PS185) on Strangeness Production
DDRH Flavour Dynamics: Single Particle Energies
DDRH Theory: Density Dependent NN and N Dirac-Brueckner Vertices
Nuclear Matter S
= 28 MeV
Phase Space Distribution for pbar+A -> anti-Y+B(Y)+pi^- Target: 40Ca
Lambda 300 200 100
Sigma^0 300 200 100
0100200300400500600700800k(anti-Y) [MeV/c] 100200300400500600700800
q(pi^-) [MeV/c]
050
100150200250300350
d^2P(k,q)/dE(k)dE(q)
Phase Space Distribution for pbar+A -> anti-Y+B(Y)+pi^- Target: 56Ca
Lambda 200 150 100 50
Sigma^0 200 150 100 50
0100200300400500600700800k(anti-Y) [MeV/c] 100200300400500600700800
q(pi^-) [MeV/c]
050
100150200250
d^2P(k,q)/dE(k)dE(q)
and Strangeness Production on Stable
and Exotic Nuclei
40Ca
56Ca
• Antiprotons as a Probe for Nuclear Structure
• Antipoton-neutron Interactions in Neutron-rich Nuclei
• Antiproton Absorption in Neutron Skin Matter:
• Exclusive Processes: Studies of A A-1 Reactions
• Multi-Pion and YY Production
• Antiproton In-Medium Interactions:
• Test of G-parity for antiproton-N interactions,
• Study of dispersive self-energies
Summary and Outlook
Antiproton Ion Collider (AIC) Collaboration @ FAIR
Measuring Neutron Skins on Isotopic Chains (Ni,Sn…):
p + A Absorption@FAIR: the AIC Proposal
P. Kienle, NMB 214 (2004) and AIC@FAIR
Proposal
H.L., P. Kienle, Phys.Lett. B647 (2007) 82-87