[Rivet] Delayed minutes!

[Andy Buckley]

Hi all,

Here are some slightly late minutes from last week's phone meeting:
please at least check the actions to see if I (or you!) forgot something ;)


RIVET GENSER INSTALL
 Lars is no longer MCnet, so it's best if someone else takes over the
responsibility of getting Rivet installed in the Genser collection. What
is the status of Rivet in the Atlas kits?
 ACTIONS:
  * Jon will install Rivet 1.1.2 on the AFS Genser area for now, and
talk to Alberto about getting write permissions in that part of Genser
for James &| Emily.


EVENT ALIGNMENT CONVENTION
 James has been re-working the DIS projections, and wanted to know what
to do about getting the electron and proton z-directions predictable. We
diecided to require conventional input events. Jon happened to mention
some HERA knowledge about HERWIG not being able to generate
photoproduction/DIS events in the HERA ep direction convention, and
hence needing to rotate/flip the event post-production. This fits with
Dan Traynor's emails to Andy about Herwig in AGILe needing negative beam
momenta to make HERA-convention events: presumably he is used to getting
ready-flipped events in H1 MC samples and HZTool analyses. We want to
add similar auto-flipping to Rivet: as well as for HERA events, which
are not our major analysis target right now, this convention affects
Tevatron ppbar events, where the effect will be more subtle, but
important. B-factory events and even symmetric e+e- presumably also have
conventions that we need to respect, perhaps on an
analysis-by-analysis/expt-by-expt basis. The beam ID checker may need to
be made ordering-specific to deal with this.
 ACTIONS:
  * Andy to mail Dan Traynor (done), plan auto-rotation in Rivet 1.2.0
(ticketed)


DESY MEETING / HERA ANALYSES
 Andy and James were guest stars at the DESY "Pheno Week". The intention
was that we would spend most of our time working with students/postdocs
and getting new HERA analyses into Rivet / converting the most important
HZTool analyses. Instead, we realised that the DESY MC Analysis group's
interest was in getting Rivet & Professor to work for Atlas, and to
bring HZTool up to date. Accordingly, we gave some talks on Rivet and
Professor and have agreed that for now most HERA analyses will probably
go into HZTool unless the author decides to use Rivet. While not ideal,
this will allow us to use HZTool to make data for validation and tuning
more easily than transcribing all the HZTool code by ourselves.
 ACTIONS:
  * Andy to make HZTool accept HepMC input (for C++ gens) and to make
Cascade write HepMC output.
  * James to look at converting HZTool output from HBOOK -> ROOT ->
AIDA/YODA
  * Andy to disable current two known-bad HERA analyses in Rivet; Jon to
fix them when he gets a chance (hmmm ;).


CDF PHOTON CLUSTERING
 We are pretty sure that our CDF Drell-Yan MC analyses, particularly the
Z and W pT spectra, are not clustering the photon emission from the FS
electrons properly. Accordingly, the Z will not typically be hard enough
in the resulting comparisons to the expt measurement. Needs to be fixed
before we do the Atlas MC tunes with Professor.
 ACTIONS:
  * Emily to look into a good definition of photon clustering (cone
size, wide angle ME-correction photons...)
  * Hendrik to forward our email exchanges with Peter Skands and
Torbjorn Sjostrand to Emily.
  * Emily/Andy/Hendrik to fix the affected analyses. Definitely a
blocker for 1.1.3.


METADATA AND DOCUMENTATION
 Andy mentioned plans to add more metadata to the Rivet analysis
classes. This metadata can then be queried from the Python interface and
used to build synchronised LaTeX entries for the analyses in the manual
and on the Web, as well as the command line: this will be much more
maintainable than having to maintain a manual entry, large Doxygen
comments, wiki pages *and* coded metadata. The intention is to have
analysis descriptions at least as complete as in the HZTool manual.
 Suggested info was: analysis author(s), long description, whether the
analysis is validated/trusted, run conditions (not gen-specific, but
info about {energ{y,ies}, process type(s), min pT in plots, whether
kinematic efficiency cuts are needed (and suggested values),
lifetime-based particle stability}, whether the reference data is
detector-corrected...
 Unfortunately, since we're naturally lazy and abhor writing
documentation, adding extra metadata methods will have to block
compilation if anyone is actually going to add anything. Andy will deal
with this. Andy has also updated the Web and bundled documentation, and
will continue to update the manual for 1.1.3. The manual should b
complete and ~stable by release 1.2.0.
 ACTIONS:
  * Andy to plan new metadata methods, send proposal around for
comments. Everyone to reply ;)
  * Andy to add new virtual methods to Analysis interface, blocking
compilation. Provide a good example analysis to be used as a template.
Send round an email associating authors to analyses which need metadata.


VALIDATOR
 Frank thinks the validator is pretty much done, except for making the
submission backend use Ganga (enables Grid submission). Andy has had
some trouble making the analysis configuration structure work well with
Pythia and the analyses used by Professor tunings, since typically
several analyses group together and most gens need to split their runs
into different kinematic regions: he will look into addressing this
structurally.
 ACTIONS:
  * Frank: get the validator plots on the Rivet website in an initial
form. Improve the HTML a required. We really want a couple of gens, but
just Sherpa vs. ref data will do fine for now.
  * Andy: try out a more flexible way of grouping analyses privately
before bothering Frank with silly ideas ;)


MORE ANALYSES
 Next focus should be on extending the hadron collider analyses to lower
energies. We have reference data for UA5 and similar in the Rivet
tarball: these analyses are typically chgd multiplicities and
pseudorapidities, and are so very easy to implement. We also want to get
some RHIC, SppS, ISR analyses in.
 ACTIONS:
  * Hendrik: Will start to implement the UA5 etc. analyses. Hendrik will
be touring the eastern US in April to talk with Rick Field and the RHIC
people that Peter Skands has been talking to.
  * Jon: find out what's happening with the RHIC/Alice student that
Frank Krauss is trying to get on a MCnet short-term studentship and make
sure Hendrik is aware of the status of that before talking to the RHIC
guys and BNL/FNAL.
  * Frank: continue adding more Tevatron analyses from the Sherpa
analysis collection.


Phew: long meeting, long minutes!
Best wishes,
Andy


-- 
Dr Andy Buckley
Institute for Particle Physics Phenomenology
Durham University
0191 3343798 | 0191 3732613 | www.insectnation.org