From grenier@ipnl.in2p3.fr Mon Jan 26 13:32:41 2009
Date: Fri, 16 Jan 2009 12:12:16 +0100
From: Gerald Grenier <grenier@ipnl.in2p3.fr>
To: d0-simulation <d0-simulation@fnal.gov>, d0_mcrep@fnal.gov,
     Tibor Kurca <kurca@in2p3.fr>
Subject: Important announcement concerning tunes

Dear all,

Starting with cardfiles version v01-01-40, there are plenty of PYTHIA 
tunes available :

Here is the link between the request-id (sam metadata) parameters in the 
generated dictionary and the tune set-up actually used :

For PYTHIA :
If the parameter 'UE_Tune_Set' is not set, then you use the tune A 'a la 
D0 pythia style'
          The tune A 'a la D0 pythia style' is different from what the 
rest of the world is calling tune A
           because it uses different PDF library and fixes Lambda_QCD by 
hand.

If the parameter 'UE_Tune_Set' is set to 'tuneA' or 'tuneAPT' or ..., 
then you use the corresponding tune 'a la D0 pythia style'
            It means that in this case, the PDF library might be 
different than from the original tune and the Lambda_QCD parameter
            is fixed by hand.

If the parameter 'UE_Tune_Set' is set to 'tuneMSTP5', then the parameter 
'MSTP5_CODE' should be set.
            In that case you use the PYTHIA routine PYTUNE that sets the 
tune parameters automatically.
            This feature is available only with D0Release p20.09.06 
(PYTHIA version 6.419) and d0runjob v07-09-14 (and higher)
            WARNING : IF YOU SELECT WITH THIS METHOD A TUNE BASED ON THE 
CTEQ5 PDF LIKE TUNE A,
                                  THIS WILL SELECT AUTOMATICALLY THE 
CTEQ5L PDF.

For ALPGEN+PYTHIA :
If the parameter 'UE_Tune_Set' is not set, then you use the tune A 'a la 
D0 alpgen style'
          The tune A 'a la D0 alpgen style' is different from what the 
rest of the world is calling tune A
          and different from tune A  'a la D0 pythia style' because it 
uses different PDF library
          but doesn't fix Lambda_QCD by hand.

If the parameter 'UE_Tune_Set' is set to 'tuneA' or 'tuneDW' or ..., 
then you use the corresponding tune 'a la D0 alpgen style'
            It means that in this case, the PDF library might be 
different than from the original tune.
            Note that in that case if you use the same PDF as the one 
specified in the tune, then it corresponds to the original tune.

If the parameter 'UE_Tune_Set' is set to 'tuneMSTP5', then the parameter 
'MSTP5_CODE' should be set.
            In that case you use the PYTHIA routine PYTUNE that sets the 
tune parameters automatically.
            This feature is available only with D0Release p20.09.06 
(PYTHIA version 6.419) and d0runjob v07-09-14 (and higher)
            WARNING : IF YOU SELECT WITH THIS METHOD A TUNE BASED ON THE 
CTEQ5 PDF LIKE TUNE A,
                                  THIS WILL SELECT AUTOMATICALLY THE 
CTEQ5L PDF FOR THE PYTHIA PART OF THE
                                  SIMULATION. IT WON'T CHANGE YOUR PDF 
CHOICE FOR THE ALPGEN PART.

A last point : the SAM metadata concerning the tune are fully exact only 
if the process cardfiles doesn't change the tune parameters by hand.
This is generally the case. There exists a few exceptions (for example 
the qcd/pythia_qcd_incl_n.PARP83_32.cards is one of the very rare 
exceptions)

Gerald


PS : the list of MSTP5_CODE corresponding to the MSTP(5) pythia parameter :

    MSTP(5) : (D=0) specification of global parameter set, if any, for
       underlying event, min-bias, bremsstrahlung (ISR and FSR), beam
       remnants, primordial kT, etc. Current available 'tunes' are:
        = 0 Default : No settings changed.
        = 100 A   : Rick Field's CDF Tune A
        = 101 AW  : Rick Field's CDF Tune AW
        = 102 BW  : Rick Field's CDF Tune BW
        = 103 DW  : Rick Field's CDF Tune DW
        = 104 DWT : DW with alternative (default) UE energy scaling
        = 105 QW  : Rick Field's CDF Tune QW 
                    Note! needs CTEQ6.1M pdfs externally
        = 106 ATLAS-DC2: Old ATLAS tune (ATLAS DC2 / Rome)
        = 107 ACR : Tune A modified with annealing CR
        = 108 D6  : Rick Field's CDF Tune D6 
                    Note! needs CTEQ6L pdfs externally
        = 109 D6T : Rick Field's CDF Tune D6T 
                    Note! needs CTEQ6L pdfs externally
        = 200 IM1 : Intermediate model: new UE with Q2-ordered showers,
        = 201 APT : Tune A modified to use pT-ordered final-state showers
        = 300 S0  : Sandhoff-Skands Tune 0
        = 301 S1  : Sandhoff-Skands Tune 1
        = 302 S2  : Sandhoff-Skands Tune 2
        = 303 S0A : S0 with "Tune A" UE energy scaling
        = 304 NOCR: New UE "best try" without colour reconnections
        = 305 Old : New UE, original (primitive) colour reconnections
        = 306 ATLAS-CSC: Arthur Moraes' (new) ATLAS tune
                         Note! needs CTEQ6L pdfs externally