attending: Andreas, Richard, Gabe, Joe C., Rocco; Marcela, Stephen
This effort is organized as a discussion group led by a steering group (Andreas Kronfeld, Sam Zeller, Joe Carlson, Richard Hill, Gabe Perdue, Rocco Schiavilla). These are notes from the first meeting of the steering group, with reps from Theory and NPC.
We agreed on the value of a white paper to understand how the imperfect knowledge of nuclear and hadronic physics propagates to error bars on θ23, δCP, and oscillation parameters in general. This one-sentence summary should be understood as breaking the uncertainties into error budget(s), so that it is clear which sources of uncertainty are largest or "squishiest". (Here "squishy" means the error estimate is not robust for some reason.)
The audience is not only QCD and nuclear theorists (who will see where reduce and firm up uncertainty estimates), but also the HEP community (who have a stake in seeing a solid error budget, but in many cases won't work on it).
This idea has some overlap with a whitepaper being planned by NuSTEC (neutrino scattering theory-expt collaboration). The latter sets the stage for a comprehensive review, including chapters ofn detector issues and other aspects of experimentation. NuSTEC does not yet have members from HEP theory, but will add them [says Jorge Morfin in a later converstation with Andreas].
Another paper to consider is an effort from the "Fundamental Symmetries" part of the NP community in the context of the NSAC long-range plan. A link to the paper is below.
A very specific question is whether DUNE will have measured δCP ≠ 0 to 5σ. This is a key question to the BSM community. We need to aim to clarify such questions now so that they can be meaningfully addressed on a ~10-year time scale. This is why it will be useful to list all sources of uncertainty, provide a provisional estimate, and give a roadmap for future research. We would like to outline the problems but not be prescriptive about the solutions. For example, if both an experiment with elementary targets or a lattice QCD calculation can determine a form factor, we flag this and leave it to experts (and funding agencies) to figure out which one is implemented.
This work will have to be cognizant of how generators, such as GENIE map final states back into initial energies. We aim to do better than comparing an amalgamation of models. Especially with DUNE, higher energies are probed (up into the DIS region). So information on highish q2, nucleon-to-Delta, and further resonances will all be needed. Also need to be clear which effects can be measured in the near detector, and which not so much.
Some uncertainties will be difficult to estimate, but simply flagging these is useful. We should write the report in a clear way: avoid jargon with preloaded meanings (e.g., MA) in favor of precise language (slope of FA(q2) at q2 = 0).
We are collecting ideas for additional theorists for the "discussion group".
Next meeting 25–27 May, when Joe Carlson visits Fermilab. Andreas will be in Germany; Rocco in Italy.
submitted 9 May [ASK]