SH: shows figure of merit proportional to 1/(vol of uncertainty in parameter space) for various LCDM plus extension models. COBE = 1 and scaled from there. Jump from Planck to PICO ~ 10^9
SH: Is this worth including? Difficult to decided because I haven't said what would be removed, probably ~1/2 page of some other section that isn't one of the key SOs. Some of the DM section for example, but no decision yet.
AT: neat and interesting, especially from CMB history viewpoint. Doesn't seem to be better than what we already have though. Doesn't answer what science is gained for $1B, or how we gain that science, or why we should pursue that science. Also needs some explanatory text, adding length. And we are fighting length limits.
AT: plot shows PICO improves on past, also seems to suggest CMB work will continue forever!
TP: y-axis parameter needs explanation. not clear to me what it is so large, 10^20s
AT: there is a nice message of COBE–>Planck jump is ~ Planck–>PICO jump.
JD: there are people (at least in Europe, SH:and elsewhere!) that think Planck cleaned up everything so there is nothing left to do. This counters that sentiment.
AE: surprising that LCDM improves from Planck–>PICO. TP: I also don't understand this.
SH/JD: Because planck is cosmic variance (CV) limited in TT, but PICO is CV limited in TT, EE, BB.
SH: we'll add LCDM (6 parameters) to plot legend so it's clear that it is plain LCDM.
TP: slope is emphasized by lines, but really is a step function.
TP: where do ground experiments fall on this plot? Change it?
SH: a good (and natural) question. answering is tricky. ferreting out what assumption ground experiments have made is hard. and the discussion is more political.
JD: agree it is difficult. it's hard to say when / if ground experiments are CV limited on these parameters. due to foregrounds, systematics. Of course PICO may be limited by those as well, but it is likely to be less so.
SH: worth extending Tim's question to CMB ground + other experiments like LSST, Euclid, DESI, . . .
JD: response to 'CMB forever' comment. We can try to add some CV limited points. Since PICO is CV limited on TT, EE, BB (AE: but not lensing). example parameters: 0.1 uK arcmin and infinitely small beam.
SH: this would be very good. concerned about an infinitely small beam since that isn't feasible.
JD: the noise level is more important as noise + the CMB damping tail sets an l_max that isn't much less than arcmin scales. CORE calculations show beam size stops mattering for small beams. What noise level to choose is an open question.
AT: Being able to say “PICO is the final CMB mission” with supporting numbers would be valuable.
TP: This could also justify the current instrument choices for PICO. Showing that $1B gets X amount of science while $10B doesn't get even close to 10X science.
SH + JD + Eleonora to talk offline about how to add some CV limits.
JD: minor note, chose WMAP at 2013 which makes a big jump for Planck. Could choose an earlier WMAP and make the curve smoother. SH: true, but not too important. this is fine.