[Powhegbox-announce] Problem with LHAPDF6

[Announcement of new releases and important bug fixes (read-only, low volume)]

Dear POWHEG-BOX users,

we have noticed very recently a feature/bug in lhapdf v6 that clashes
with the setting of the pdf set via a standard input card in POWHEG-BOX
(the usual powheg.input file in subprocesses directories).

Basically, with lhapdf v6, it can happen that the lhapdf library changes
the pdf set used during the run. We believe this is a 'bug' of the
fortran interface to lhapdf v6 (in particular the getq2min subroutine).
A. Buckley (LHAPDF author) has been already contacted about this. We
have also implemented a workaround in our code to minimise the risk of
similar problems in the future, which is available since revision 2819.
An announcement about this bug fix can also be found in the POWHEG BOX
webpage http://powhegbox.mib.infn.it/release_bugs.txt

If you have used POWHEG BOX (V1 or V2) with lhapdf v6, we would strongly
suggest to re-perform those runs, in all cases, but especially if you
have used also not just the central member of a pdf set (like for
instance 21201 and not just 21200 in MSTW2008nnlo, or similarly for all
other pdfs!)

Best wishes,
the authors
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