[Rivet-announce] Rivet 1.9.0 released (last 1.x version)

[Andy Buckley]

Dear Rivet users,

We are pleased to announce the release of Rivet version 1.9.0 (as some
of you may already have noticed, since it has been on the website since
Friday). It has already been built by the Genser team (thanks!) and
hence is available for immediate use by the LHC experiments and anyone
on an SLC Linux system with CERN AFS mounted. You can of course get the
source distribution from the usual place: https://rivet.hepforge.org/

This release contains two important sets of updates:

 * Many new analyses from ATLAS, CMS and LHCb, supplied to us during the
run up to Rivet 2.0 release. Thanks to all those involved in preparing
and validating these analysis codes.

 * The default behaviour of photon clustering to charged leptons in the
WFinder and ZFinder projections (via the LeptonClusters projection) has
been changed to exclude photons from hadronic decay sources, e.g. pi0 ->
gamma gamma. This should provide a better match to most experimental
charged lepton calibration, while remaining generator-portable and
physically factorised from the hard process (unlike, for example,
distinguishing between initial and final state radiation). It is not
*guaranteed* to be the correct thing to do, however, so please ensure
that you choose the lepton clustering approach appropriate for your
experiment's calibration.

Once again, we note that this is planned as the last ever release in the
Rivet 1.x series, with the AIDA histogramming system. Unless serious
bugs are found which would disrupt operational use, all future Rivet
releases will be in the 2.x series, starting with version 2.1.0 which
will include the same new analyses and W/Z finder changes as above, plus
further developments.

Best wishes,
Andy & the Rivet team

-- 
Dr Andy Buckley, Royal Society University Research Fellow
Particle Physics Expt Group, University of Glasgow / PH Dept, CERN