C-REX (little sister of PREX) : Parity-Violating Measurement of the Weak Charge radius of 48Ca to 0.03 fm. 1-pass (2.2 GeV) HRS + septum

C-REX Workshopat JLab March 17 – 20, 2013 40 Participants from several fields 19 talks & discussions

PAC39 result :• C2 approval

• return with stronger case demonstrating how C-REX tests microscopic models (e.g. 3-neutron forces)

R. MichaelsHA mtg 3/26/13

P1/4

PREX II and C-REX208Pb approximates infinite nuclear matter -- ~ a small neutron star

48Ca smaller, optimizes at higher Q2 (natural 11 GeV expt).

Lots of neutrons, sensitive to 3N force

Tests micrscopic models for neutrons. ( PAC39: “explain this !” )

Want doubly-magic nuclei: little coupling to inelastic -- “clean”

Want neutrons : weak interaction couples to neutrons

208Pb 48Ca

P2/4

Interfaces providecrucial clues

dimension of the problem

Witek Nazarewicz’s talk: Why C-REX after PREX ?

48Ca: bridge between microscopic and DFT

New microscopic theory results were presented at workshop.

P3/4

Gandolfi et al. PRC85, 032801 (2012)

Witek Nazarewicz’s talk: Why C-REX after PREX ?

C-REX 3N forces important for neutron stars

Fini