Hi all
So, let’t meet tomorrow at 3pm GMT (9am CT).
Readytalk access number: 1189892
Intl’ telephone numbers: https://www.readytalk.com/rt/an.php?tfnum=8667401260
There will be at least one document on data comparisons using v3.0 configurations,
and a set of slides on plans and work towards v4.0, sent to this list before the meeting.
Will aim to circulate material at least an hour in advance to give people some time to digest.
Please post any other relevant material you want to discuss.
cheers
Costas
On 21 Nov 2016, at 17:47, Jeremy Wolcott <[log in to unmask]<mailto:[log in to unmask]>> wrote:
Hi all,
After an extended discussion Hugh & I had this morning, we'd like to add another candidate item for this meeting: the reweighting knobs for nonresonant pion production (RvnCC1pi, etc.). After the paper from Rodrigues et al. describing how they were able to make GENIE agree much better with revised bubble chamber data from ANL & BNL (https://inspirehep.net/record/1414604) by reducing the predicted nonresonant pion production at low W, this has become something of a front-line issue. I know of at least two experiments (MINERvA and NOvA) who are applying post facto corrections to GENIE according to that paper because it substantially affects their predictions, and it's probably worth our trying to decide how we can incorporate it into the default tune.
Perhaps more immediately, in looking through the reweight knobs to understand exactly what Rodrigues et al.'s tuning was doing, I noticed something which seemed kind of unusual: the R{v,vbar}{n,p}{CC,NC}{1,2}pi knobs all apparently affect DIS events with W < 2.0 GeV (see Doxygen for GReWeightNonResonanceBkg<https://genie.hepforge.org/doxygen/html/classgenie_1_1rew_1_1GReWeightNonResonanceBkg.html>; note that member fWmin, which should probably actually be called fWmax, is set to 2.0 GeV in Init()). This seems sort of unusual in that the usual crossover point for things of this nature (e.g., cutoff of resonant pion production) is W=1.7 GeV. We were lead to a few questions, which we can discuss tomorrow:
1. Was this (upper bound of 2.0 GeV instead of 1.7 GeV) the intent? If so, what was the rationale?
2. The usual philosophy for the reweight knobs is that by turning them, one arrives at the same effective event sample as one would have by running GENIE with a modification to some config parameter(s). On the face of it, this situation seems to break that prescription. Is that actually the case?
3. Does the current situation double-count uncertainties (especially in the 1.7 < W/GeV < 2.0 region) that are handled by some other knobs?
4. Are there known users who depend on the current behavior, or could it be modified if we decide that any of (1)-(3) represent problems?
-Jeremy
On 11/11/2016 07:04 AM, Costas Andreopoulos wrote:
Hi all
Are you available for a GENIE meeting on Nov 22 (at the regular GENIE slot) focussing
on work for v3 and v4?
Could discuss:
-----
1) Quantitative characterisation of proposed model configurations for v3
A report is now being drafted by Marco, Anselmo and Rhiannon as they start to see and
digest the comparisons outputs. Hopefully this can be circulated a couple of days before
the meeting.
2) Next steps with v3
- Identifying and sorting out problems with model configurations.
- Deploying code to support multiple comprehensive model configurations
- Reiterating on v3 scope.
3) Progress with Prof/GENIE interface and plans for v4
We have a staged QE+MEC tuning exercise (6 stages from a trivial fit to a full analysis)
in order to sort out the Prof/GENIE interface specifics and develop all production scripts.
There is also now, I think, a quite good understanding of what is needed from our side.
Recent and ongoing devel in the Comparisons in order to be able to include all possible
correlations simplifies the interface to Professor. Depending on how responsive the Professor
authors are, we may have stage 1 done, so could discuss experience / issues.
cheers
Costas
--
Dr. Constantinos Andreopoulos
Reader (Associate Professor) in Experimental Particle Physics
University of Liverpool & STFC Rutherford Appleton Laboratory
+44-(0)7540-847333 (Mobile)
+44-(0)1235-445091 (Office/RAL)
+44-(0)1517-943201 (Office/Liverpool)
http://costas.andreopoulos.eu<http://costas.andreopoulos.eu/>
https://valor.pp.rl.ac.uk<https://valor.pp.rl.ac.uk/>
https://genie.hepforge.org<https://genie.hepforge.org/>
