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) (n through (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 (sin 2 W at low- energy) V ud 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 cant 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 An e - photofission driver would use nearly identical actinide targets and extend ISACs physics reach into more neutron rich isotopes relevant to r- process nucleosynthesis