UCSD-2019: Analysis/Pipeline Working Group: Low-ell BB

Charge

Identify key decisions that must be made (and justified) prior to CD-1,
Make progress on (or actually make) those decisions,
Lay out a timeline and process for making each decision, consistent with the post-decision work and internal reviews that will be needed to complete preparations for CD-1,
Ensure that those timelines and processes are understood and supported by the collaboration, and that we (together) believe we can follow them.

How do we optimize detector allocation across frequency in the face of uncertainty about foreground properties, for both the SATs and the delensing LAT?
What are the advantages of split bands? How does performance compare to non-split bands?
Do we need a 20 GHz channel on delensing LAT (for SAT science)
How well will de-lensing work in practice?
What are the necessary analysis tools to answer these questions?

Background/clarifying questions:

What does “by CD-1” mean, and what are the implications for when tools need to be in place and working?
- According to APC white paper (https://arxiv.org/abs/1908.01062), CD-1 is in Q3 of FY2021 (so June 2021?).
  - But according to project office, "Plan [must be] finalized by start of 2020 for delivering...CD-1"
- Working backward from there, any tool that could reasonably influence a CD-1 decision needs to be in place and working by ... ?
- Give an example timeline for an example decision?

Introduction by everyone in the room: who? where? what aspects of low-ell BB interest you? 5 minutes
Recap of the plan for this session/CD-1 goals slides[Wu], 3 minutes
Review of Fisher based S4 forecasting thus far leading to DSR appendix A [Ben/Victor/Raphael], 15 minutes
Review of Map based S4 forecasting thus far and ideas for next steps Clem, 10 minutes
Review of forecasting and simulations for Simons Observatory inflation science [Alonso / Errard / Sherwin], slides 30 minutes
Plans for working group [all], ~60 minutes
1. Forecasting
  - Quantitative comparison of SO and CMB-S4 DSR forecasts
  - Optimization of delensing effort: update for DSR sensitivity, motivation for frequency coverage, feedback from real delensing efforts
2. Data Challenge simulations
  - More / better foreground models
  - Instrumental systematics
  - Other map non-idealities, i.e. filtering / mode loss
  - Coordination with technical groups on instrument configuration, etc
  - What else needs to be demonstrated for CD1?
  - Bottlenecks for sim production
3. Analysis of Data Challenges
  - Who plans to participate? How do we get more participation?
  - Delensing
4. Specific Data Challenge plan / timeline
  - Experiment config 06: DSR configuration, in progress
  - Update / reoptimization of delensing survey?
  - Inclusion of instrumental systematics -- which ones? how to include?
  - Data Challenges coming out of Data Management group