ISAC Physics Working Group

Convenors

Malcolm Butler and

Barry Davids

Subgroups

• RIB Production and Ionization (Dan Stracener)

• Nuclear Structure(John Wood)

• Nuclear Astrophysics(Chris Ruiz)

• Fundamental Symmetries(John Behr)

Physics Goals (1)

Key unanswered questions:•How old is the universe?•Where and how are the elements created?•How do stars evolve and explode?•What is the fate of matter on compact stellar objects?

A well-developed program to better understand heavy-element nucleosynthesis (“the r-process”) and other key nucleosynthesis pathways

Methods and Examples

Masses (TITAN)• Constrain the nucleosynthesis pathways • Determine neutron star crust composition• Influence abundances during core-collapse

supernovae

Half-lives (8, TIGRESS-EMMA)• Influence r-process reaction flow, duration, and

final abundance distribution

Methods and Examples

Reactions and Structure (DRAGON, TUDA, TACTIC, TIGRESS, EMMA, SHARC)

• (nthrough (d,p), for final r-process abundances• (p,), (), (p,), and (,p) determine x-ray burst light

curves, determine abundances of characteristic gamma-ray emitting isotopes (gamma-ray astronomy targets)

• Understand underlying structure (e.g. single particle behaviour, pairing, deformation, etc.) – impact on “waiting points”, extrapolations to the dripline, microscopic weak interaction rate calculations for SN

• Theory interface key to moving forward with indirect methods

Physics Goals (2)

Use of atomic and nuclear systems for tests and probes of fundamental symmetries, their possible violation, and the search for new physics beyond the SM

•Search for electric dipole moments/EDM (T-reversal violation)•Atomic parity non-conservation/APNC (sin2W at low-energy)•Vud and CVC tests (scalar and tensor interaction searches)•Right-handed and second-class currents

Methods and Examples (2)

Atom Traps and beta-decay spectroscopy (TRINAT and beyond)

• APNC, nuclear anapole moments, EDM (Fr program)

coincidence spectroscopy (TIGRESS)• Rn EDM• Need structure studies of Rn isotopes to identify

best candidates (currently guided by theory)

Facility Reach

Actinide targets yield both extremely neutron rich nuclei and heavy nuclei needed for fundamental symmetry studies that can’t be produced otherwise

Photofission would extend the reach to more neutron-rich isotopes of some key elements, particularly in regions around r-process waiting points, and produces fewer problematic isobars than proton-induced fission

Photofission would allow for continued studies during cyclotron shutdowns

Full facility with target stations and personnel would permit delivery of more RIB hours/year than any other ISOL lab

Second proton beam line would allow:•experimental studies of both proton and neutron-rich nuclei simultaneously•decoupling of target/ion source development and RIB production

Lab resources key to success

• Need support for target and ion source development, and must decouple RIB production and development

• Demands on technical and operational staff substantially greater to enable two simultaneous experiments

Summary

TRIUMF must construct a second proton beamline with at least two target stations and implement an actinide target in order to maintain its world leadership in RIB science through 2020.

An e- photofission driver would use nearly identical actinide targets and extend ISAC’s physics reach into more neutron rich isotopes relevant to r-process nucleosynthesis