Monopole

This is an outcome of a workshop devoted to E0 transitions in atomic nuclei, held at Australian National University, Canberra, Australia, Sept 11-12, 2015, organized by Tibor Kibèdi (Chair), Andrew Stuchbery, and Greg Lane.

E0 Focus Group - mission statement
To my knowledge, in the 40 years that I have been engaged in studies of nuclear structure, with an active interest in E0 transitions in atomic nuclei, this was the first-ever meeting dedicated to the topic.

''It was decided by the attendees that this was a unique opportunity to launch a focus group with interest in E0 transitions in atomic nuclei and topics related to this subject. Therefore, this Wiki is a commencement of this resolve.''

''A leading interest in E0 transitions is their association with shape coexistence in atomic nuclei. Also, this is the only process by which a transition can occur between two nuclear states, each having spin parity 0+.''

''I anticipate that the wiki initiated herewith will evolve into a documentation of the E0 process--its history, manifestations, underlying physics, and role in the elucidation of nuclear structure. The last aspect of the E0 process will be the dominant theme.'' — John L. Wood

Key criteria for E0 studies
Experimental
 * Measurement of Ice or Iπ is difficult
 * Determination of δ(E2/M1), for E2+M1+E0 transitions, is difficult. (Multi-detector geometries, angular momentum algebra)
 * Measurement of T1/2 is difficult. (Needs decision on electronic timing versus RDDS or DSAM, indirect feeding issues.)
 * Demonstrating "no γ-rays" for pure E0 is difficult.

Theoretical
 * Straightforward for two-state mixing and Δ prescription.
 * Need to explore Paul Garret`s approach to two-state mixing and Δ<β2> prescription via E2 matrix elements and Kumar-Cline sum rules.

General remarks
 * There is a lack of familiarity with the formulation of E0 transition strength, both with the experimental input quantities and with the theoretical details.
 * Experimental demands are likely regarded as intimidating by most persons.
 * Two-state mixing involves "a lot" of parameters.
 * ENSDF does not handle E0 transition strength in any well-defined manner
 * Treatment of E0 transition strength in various theoretical frameworks is haphazard because the model-dependent formulation of the E0 operator is ambiguous. Also, theorists are not familiar with the available data because it is not in ENSDF.
 * There does not appear to be an obvious "unit" suited to quantify E0 transition strength. (Note that ρ2(E0) is dimensionless.)

Spectroscopic information on pure E0 and mixed E0+E2+M1 transitions
Recommended evaluated and published values are from:

Pure E0: T. Kibédi and R.H. Spear, [http://www.nndc.bnl.gov/nsr/nsrlink.jsp?2005Ki02,B At. Data and Nucl. Data Tables 89 (2005) 77]

E0+E2+M1: J.L. Wood, E.F. Zganjar, C. De Coster and K. Heyde, [http://www.nndc.bnl.gov/nsr/nsrlink.jsp?1999Wo07,B Nucl. Phys. A651 (1999) 323]

Additional entries are from:

J.L. Wood from available ENSDF data

Available ENSDF data has the relevant Nuclear Data Sheets citation.

Founding members
Tibor Kibèdi User:TiborKibedi

John L. Wood

E0 workshop, ANU, 11th – 12th September 2015
The workshop was organised as part of the HIAS 2015 and the full program is here.

Presentations:
 * John Wood (Georgia Tech) [[Media:JohnWood_2015E0.pdf|E0 transitions: where we have been, where we are going, where we would like to go ]]
 * Tibor Kibedi (ANU)
 * Rob Bark (iThemba)
 * Hiroshi Watanabe (RIKEN)
 * Tomas Eriksen (ANU)
 * Eiji Ideguchi (RCNP)
 * Lee Evitts (TRIUMF)
 * Paul Garrett (Univ. Guelph)
 * Mitch Allmond (ORNL)
 * Greg Lane (ANU)
 * Boon Q. Lee (ANU)
 * Robert Page (Univ. Liverpool)
 * Steve Yates (Univ. Kentucky)

John L. Wood (email: john.wood@physics.gatech.edu; School of Physics, Georgia Institute of Technology, Atlanta, USA)

 * [[Media:JLW-_Lectures_undergrad_QM_(dupl).pdf|"Lectures undergrad QM"]]

References and Notes
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