+ 2 208 Pb Electroweak Asymmetry in Elastic Electron- Nucleus Scattering : A measure of the neutron distribution PREX and CREX 48 Ca Neutron Skin Horowit z Robert Michaels Jefferson Lab CIPANP 2015 1/15 0 Z e e 6 2 4 10 ~ 10 ~ Q A L R L R PV 2 2 p n p n r r R R
15
Embed
+ 2 208 Pb Electroweak Asymmetry in Elastic Electron-Nucleus Scattering : A measure of the neutron distribution PREX and CREX 48 Ca Neutron Skin Horowitz.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
0Ze e
+
2
624 10~10~
QALR
LRPV
208Pb
Electroweak Asymmetry in Elastic Electron-Nucleus Scattering : A measure of the neutron distribution
PREX and CREX 48Ca
22pnpn rrRR
Neutron Skin
Horowitz
Robert Michaels Jefferson Lab
CIPANP 2015
1/15
48Ca
208Pb
Choice of Nuclear Targets• First excited state far from elastic• Neutron excess• Doubly-magic• Stable
Hall A
Hall AHigh Resolution ( 10-4 ) Spectrometers
)(
)(sin41
22 2
22
2
QF
QFQGA
P
NW
F
Neutron form factor
Robert Michaels, CIPANP 2015
Neutron Skin vs Mass Number AR N
– R
P (f
m)
A
PREX-I PREX-IIpublished Approved proposal
C-REXApproved proposal
3/15Robert Michaels, CIPANP 2015
Measured Asymmetry
Weak Density at one Q2
Correct for CoulombDistortions
Small Corrections fornEG
sE MEC
surface thickness
Atomic Parity Violation
Neutron
Stars RN - RP
Weak Interaction: Sees the Neutrons
G
Nuclear Theory (Symmetry Energy )
Skin
proton neutron
Electric charge 1 0
Weak charge 0.08 1
APPLICATIONS
Heavy
Ions
Ways to Find
Neutron Distribution and Symmetry Energy
• Proton-Nucleus Elastic• Pion, alpha, d Scattering• Pion Photoproduction• Heavy ion collisions• Rare Isotopes (dripline)• Electric Dipole Polarizabilities
• Magnetic scattering
• PREX / C-REX (weak interaction)
• Theory MFT fit mostly by data other than neutron densities
Involve strong probes
Most spins couple to zero.
5/15
)(PInput :
Eq. of state (EOS)
Deduce Mass-Radius relationship, and other properties
PREX / CREX helps here
pres
sure
dens
ity
Neutron skin is highly correlated with several neutron star properties