September 13, 2007, 3pm EDT

Topic 1: Review of the BEPAC deliberations and findings by Mark Devlin and Stephan Meyer,

DEVLIN: Competition for top three slots in survey (JDEM, Con-X, LISA) was very tough. Two missions have broad appeal (Con-X, LISA ) and they serve larger communities. LISA had very exciting science compared with other Beyond Einstein (BE) missions. JDEM, all flavors, returns much more data than that needed to get the single Dark Energy measurement, also had very little technology development needed.

Costs were not that big a discriminator.

Technology not in place for CMBPol, measurement fantastically difficult to make, raw challenge for sensitivity in the face of unknown systematics and foregrounds. Potential of a null result. Interest level not high in general for the science. The Inflation Probe was categorized as an 'experiment'.

KRAUSS: sounds like “they wanted LISA, but it¹s not ready so we¹ll take JDEM”.

DEVLIN: Even if JDEM does not produce any exciting science about dark energy, which is a real possibility, one gets 3000 Hubble Deep Fields.

The committee had to take cost and risk into account, and therefore the committee could not saddle NASA with a long term LISA program with unknown technology development costs. That is part of the reason LISA was not chosen to be first.

MEYER: Committee focused on the question of BE science. All missions, with some caveats about Con-X, were worthy BE science. So question is where do you start? LISA's goals are very hard to match in fitting the BE science goals, but it is not the place to start, given the technical challenges.

JULIAN: The report said Con-X is not really a BE mission. Could someone elaborate?

MEYER: There was a preception that Con-X was shoe-horned into BE. It is really too broad. It¹s primary strength is not the BE central themes.

MILLER: Eq. of state not much better (cf. JDEM), or broader than CMBPol.

DEVLIN: Con-X does many BE things, but not as well as specific missions like LISA, JDEM.

MEYER: if w=-1, then you learn nothing more than you know now. However it nails it down for good. LISA should get a s/n of 100 on details of gravity wave signal. That is very exciting. But LISA Pathfinder results must be known before NASA can move forward.

DEVLIN: CMB science not well favored, community too small, too divided. There is a “who cares” (about inflation) factor combined with the possibility for a null result. Should also note that Cosmic Inflation Probe (CIP) is easier technology, and it gets broader ancillary science.

HINSHAW: But CIP doesn't get the energy scale of inflation.

Political factors did not enter the BEPAC report deliberation. That is, there was no consideration of how agencies interact, how ESA may move, etc.

HANANY: Clearly the CMB science needs better explanation, more support from broader astrophysics and particle physics crowd. Case for ancillary science needs to be made stronger; need to enlist the community that cares about the ancillary science, those doing galactic dust, for example.

DEVLIN: CMB scientists should give talks to particle physicists, making the Inflation Probe an inevitable mission. Currently this is not the case. Other groups (JDEM, LISA, Con-X) had an air of inevitability to them.

Discussion of how much needs to be invested to keep a mission alive (5-10% of a mission costs). If however, you spend enough to keep all 5 BE missions alive, you can never new start.

KRAUSS: Would ground based CMB results move up the time scales for the CMB space mission?

MEYER: If this committee (PPPDT) could change the perception of the rest of the community about the CMB world that might help the case. A more unified front would be better.

Krauss(?): A plus for CMB, is that the theoretical understanding is extremely well developed.

TOPIC 2: COMMON CMB proposal

What¹s taking shape: omnibus CMB proposal/report where the science case and foregrounds sections are done all together. May elect to cost between 1-3 example missions, 1 HEMT, 1 or 2 aligned around current bolometric missions. PI will coordinate science and foreground with subgroups working daughter missions themselves. Commonality in data analysis could be factored in as well.

Don¹t want to make every option equal. Should pick a favorite.

Report should build upon Weiss committee, mission in the next 1-3 years means that bolometers would be the choice.

Future is likely to mean only one satellite with only one technology.

Next step would be in selecting a PI for a proposal.

Is everyone on board for one proposal? One report will be more coherent, as a community. YES would seem to be the answer.

How will a single presentation be made? Ultimately will not want to present a menu to the decadal.

Should send email to community that we want to go as a community, advertise the work of the PPPDT to others that they can participate. Shaul will compile a draft letter, and solicit nominations ­ anyone we know within the CMB community.