Legend: Bold face encodes 'need more information'; italics encodes issues that are (semi)settled in the sense that they are the basis for future discussions; Underlined Text are action items.

• Requirement on r:
  • Need to motivate the target. We can't have a fishing expedition. 'Let's get as low as we can' won't work as a justification. There needs to be a well motivated requirement. Raphael says that it would be hard to motivate the level of r based on specific models, but one should be able to generate motivations based on fundamental physics and classes of theories. In the proposal we argued for particular goals (and were limited by foregrounds). Raphael will organize a group of people who will work on a particular target. The S4 science book targets r<0.002 at 95%.
  • The connection between limits on r and resolution: does the limit on r depends on delensing, and if so, how much delensing, and how does that relate to the resolution? The probe is unlikely to have an aperture larger than 2 m. Amy says it is likely to be less than 1.5 m. Charles argues that delensing will be complicated by foregrounds. Shaul suggests first understanding how much delensing is necessary, and its connection to resolution without the complication of foregrounds. All agree that foreground complications will have to be addressed as well.
  • Alex Van Engelen and Blake Sherwin were mentioned as some who can contribute analysis.
  • Lloyd will organize study of delensing. Question: “what is the level of r that can be achieved as a function of resolution and depth?”
• Foregrounds: we will need to assess foreground cleaning. Clem, Julian, Raphael, point out that a pipeline exists for S4 and can be used for the Probe. It will be adapted to handle full sky.
• A discussion ensues about the need for various different groups to analyze the data without assuming the input models. We will announce the availability of maps (when available) and invite anyone interested in contributing. Lloyd will coordinate this 'data challenge'. Julian will allocate space at NERSC.
• The challenge will need frequency bands and noise levels. Shaul is responsible to provide.
• Al suggests a kick-off workshop to discuss foreground approaches and to help coordinate the community. Shaul will communicate the suggestion to Jamie/Graca (coordinators of the KISS workshop).
• Spectrometer:
  • what is the motivation for a stand alone super-pixie?
  • what is the motivation for compspec (=complementary spectrometer)? Al: excellent foreground removal, and T information that can extend the science by cross-correlating with optical survey.
• Al will organize a group that will assess the motivation for a super-pixie and/or develop the case for compspec. How will such a complementary spectrometer look like? Is it a mini-pixie?
• Other science: 'What is the dream data set that the galactic magnetic field and dust afficionados would like to see'? Shaul will write to Darren Dowell, and Giles Novack to check who from these communities is interested in participating. Bill Jones will talk with Aureliene