[Rivet] Validation & tuning phone meeting, Monday 29th Sept, 4pm (UK)

[Lars Sonnenschein]

Hello all
please find at http://www-d0.fnal.gov/~sonne/D0_2001_S4674421/
plots which compare data to simulation,
twice for Pythia 6413 + TuneA (twice because in lin and log y plots)
and twice for Herwig 6510 (without Jimmy and without parameter settings 
different from default, to start with)

The top left plot shows the W pT xsec. The top right plot the Z pT xsec.
The bottom left plot shows the same data as the top right plot (Z pT xsec)
but with the dsigma/d(pT(Z)*mW/mZ) of the simulation.
Presumably I compare here apples with oranges but at least you can see 
what is different with and without the scaling.
The ratio (bottom right plot) seems already to look better for Herwig.

Concerning the overal normalisation there is an ambiguity:
boson->tau->electron.
I didn't switch this on, since the papers only talk about boson->e('s) 
without intermediate tau. This would increase the xsec roughly by 1/3, but 
the pT spectrum of the electrons from taus is also a little bit different.
So if I would switch boson->tau on, it depends on how the experiment has 
corrected (to boson->e('s) or to boson->e('s) + boson->tau('s)->e('s)).

In Pythia I can switch on boson-> e,tau. In Herwig I can only choose 
either boson->e or boson->lepton which requires different normalisations
afterwards. Herwig I have to run twice, once for W and once for Z 
production, so the ratio has to be determined offline with Herwig anyway
(as far as I know).

Now cencering Herwig + Jimmy:
What arer the right switches (John?)
Right now I have put:

JMUEO = 1
MSFLAG = 1
PTJIM = 3.0
PRRAD = 2.13

(I guess I found this somehwere some time ago and copied and pasted)
What would be appropriate parameter settings?
I get plenty of warnings: HWNSCT WARNING:TOO MANY SCATTERS IN EVENT
and it takes for ever to get 100 events analysed in Rivet.
Like that I cannot run with Jimmy.

Then for the W and Z tuned parameters:
In Emilys report there is a table on page 43 with different parameter 
settings (PTRMS, QCDLAM and VQCUT) for W and for Z boson production.
Should I use these of the 2nd tune in this table?


So far

	Lars


On Mon, 6 Oct 2008, Emily Nurse wrote:

> Hi Lars,
> 
> I think you will need to correct for the branching ratio difference as this is
> a ratio of production cross sections , so your formula
> > R_th = dsigma/dpt(W) / dsigma/[d(pt(Z)*Mw/Mz)] *
> > B(Z->ee)/B(W->enu)
> 
> looks correct - although its been a long time since I read the paper. If the
> normalisation looks off lets re think it.
> 
> Cheers,
> Emily.
> 
> On 6 Oct 2008, at 09:48, Lars Sonnenschein wrote:
> 
> > Hello Emily
> > thank you for your feedback.
> > Indeed the paper has two formulas for the ratio:
> > a theoretical one which corresponds to your formula below and an
> > experimental one which looks like:
> > 
> > R_exp(pT) = [dsigma/dpt(W) / dsigma/dpt(Z)] * Mw/Mz * B(Z->ee)/B(W->enu)
> > 
> > where Mw/Mz = 0.88 and B(Z->ee)/B(W->enu) = 0.3 roughly.
> > The later formula I use for the ratio, i.e. scale the diff. xsec. ratio
> > by the constant factors given above.
> > 
> > Now I could scale the Z pT before filling the histo according to the
> > theoretical formula, but that would not alter the W pT spectrum.
> > 
> > Though I will try to see the difference in the ratio.
> > 
> > Now, since I select electrons (and  a neutrino in case of W) should the
> > formula look like R_th = dsigma/dpt(W) / dsigma/[d(pt(Z)*Mw/Mz)] *
> > B(Z->ee)/B(W->enu)
> > to take the branching ratio differences into account?
> > 
> >      Lars
> > 
> > 
> > On Mon, 6 Oct 2008, Emily Nurse wrote:
> > 
> > > Hi Lars,
> > > 
> > > Its hard to see how off the W pT plot is, can you compare it to the data
> > > so we
> > > can see?
> > > As for the ratio, its more obvious that its going the wrong way compared
> > > to
> > > the data.
> > > In the paper they are measuring dsigma/dpt(W) / dsigma/[dpt(Z)*Mw/Mz]
> > > ie/ they scale the Z pT by the ratio of the W and Z masses, see page 20
> > > and 21
> > > of my 1st year PhD transfer report for more details, and comparisons of
> > > the
> > > data with Herwig:
> > > http://www.hep.man.ac.uk/u/emily/1styear.ps
> > > 
> > > It should also be explained in the paper. Are you doing this in the
> > > routine?
> > > 
> > > Cheers,
> > > Emily.
> > > 
> > > 
> > > On 6 Oct 2008, at 08:19, Lars Sonnenschein wrote:
> > > 
> > > > Hi
> > > > I have put some plots for the D0 2001 WpT <-> ZpT analysis at
> > > > http://www-d0.fnal.gov/~sonne/D0_2001_S4674421/
> > > > 
> > > >      Lars
> > > > 
> > > > 
> > > > On Fri, 3 Oct 2008, Andy Buckley wrote:
> > > > 
> > > > > Hi everyone,
> > > > > 
> > > > > Our next Rivet etc. phone meeting will take place on Monday at 2pm (UK
> > > > > time). Note that it's earlier than last week - this will be the normal
> > > > > time from now on.
> > > > > 
> > > > > Once again, we'll be using the DESY phone conference system: phone
> > > > > 
> > > > > +49 40 8998 1390
> > > > > 
> > > > > then enter conference code 74838 ("rivet") followed by #.
> > > > > 
> > > > > From the UK, Telediscount can be useful if your office restricts
> > > > > international dialling: 0844 861 3535.
> > > > > 
> > > > > Have a good weekend!
> > > > > Andy
> > > > > 
> > > > > _______________________________________________
> > > > > Rivet mailing list
> > > > > Rivet at projects.hepforge.org
> > > > > http://www.hepforge.org/lists/listinfo/rivet
> > > > > 
> > > > 
> > > > -- 
> > > > 
> > > > 
> > > > ________________________________
> > > > Lars Sonnenschein
> > > > ________________________________
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> > > > CH-1211 Geneve 23
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> > > 
> > 
> > -- 
> > 
> > 
> > ________________________________
> > Lars Sonnenschein
> > ________________________________
> > Home Institution:
> > PH/TH 53/1-052
> > CERN
> > CH-1211 Geneve 23
> > Switzerland
> > Tel.:+41(22)767-2801
> > --------------------------------
> > ________________________________
> > FNAL:
> > D0, PK151
> > Mailstop #352
> > Fermilab, P.O.Box 500
> > Batavia, IL 60510-500
> > USA
> > Tel.: +1(630)840-8740
> > ________________________________
> 
> 

-- 

 
________________________________
Lars Sonnenschein    
________________________________
Home Institution:
PH/TH 53/1-052 
CERN
CH-1211 Geneve 23
Switzerland
Tel.:+41(22)767-2801
--------------------------------
________________________________
FNAL:
D0, PK151
Mailstop #352
Fermilab, P.O.Box 500
Batavia, IL 60510-500
USA
Tel.: +1(630)840-8740
________________________________