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Investigate model uncertainties OLD/NEW. NEW. OLD. Include only variation of charm mass and beauty mass mc:1.35 →1.5 GeV and mb: 4.3 → 5.0 GeV This model dependence was invisible – and its still invisible. NEW. OLD. Include only variation of charm mass and beauty mass - PowerPoint PPT Presentation
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Investigate model uncertaintiesOLD/NEW
Include only variation of charm mass and beauty mass
mc:1.35→1.5 GeV and mb: 4.3 →5.0 GeV
This model dependence was invisible – and its still invisible
OLDNEW
Include only variation of charm mass and beauty mass
mc:1.35→1.5 GeV and mb: 4.3 →5.0 GeV
This model dependence was invisible – and its still invisible
OLDNEW
Include only variation of strange fraction fs: 0.25 →0.40
Makes very little difference in the total Sea, but affects sea flavour break-up
New/OLD look the same
NEWOLD
Include only variation of strange fraction fs: 0.25 →0.40
Makes very little difference in the total Sea, but affects sea flavour break-up
NEW/OLD look the same
NEWOLD
Include only variation of charm fraction fc:
0.10 →0.20 OLD 0.07 → 0.11 NEW
A smaller effect than fs: makes very little difference in the total Sea, but affects sea flavour break-up Couldn’t see it before- Can’t see it now!
NEWOLD
If you look at flavour break-up U/D you can see that the fc matters less than it did..make a tif file?
NEWOLD
Include only variation of charm fraction fc:
0.10 →0.20 OLD 0.07 → 0.11 NEW
A smaller effect than fs: makes very little difference in the total Sea, but affects sea flavour break-up This model dependence is smaller now as it should be!
NEW
Include only variation of starting scale Q02: 2 → 6 GeV2
Has a small asymmetric effect on PDF ucertainties
NEW/OLD look the same
NEWOLD
Include only variation of starting scale Q02: 2 → 6 GeV2
Has a small asymmetric effect on PDF ucertainties
NEW has slightly smaller model dependence than old- this is also as expected
NEWOLD
Include only variation of minimum Q2 of fitted data Qmin2: 2.5 → 5 GeV2
Has an even smaller asymmetric effect on PDF ucertainties
NEW/OLD look the same
NEWOLD
Include only variation of minimum Q2 of fitted data Qmin2: 2.5 → 5 GeV2
Has an even smaller asymmetric effect on PDF uncertainties
NEW/OLD look the same
NEWOLD
But what about u,d,s,c?
BUT we never showed the world flvaour break-up
Now there really IS a new/old difference ..where does it come from?
OLD
Old has just mb and mc…New haS JUST mb..beacuse it is no longer true that changing mc gives no model dependence!
But look at flavour break-upNEW
OLD
Old has just mb and mc…New haS JUST mc.. it is no longer true that changing mc gives no model dependence! This makes sense. In dynamic generation the amount of charm does change with mc
NEWOLD
But look at flavour break-up
For the variation of fs, flavour break-up has not changed- good!
NEWOLD
But look at flavour break-up
Fc used to make a difference because it was imposed. But with dynamic generation fc does Not change only the Ubar Dbar relative norm has changed
NEW
NEW
OLD
Change of Q0 used to affect the flavour break up a lot because fs and fc were not changed accordingly. Now they are changed it is not a big effect.
I think this makes sense
NEWOLD
The effect of the Q2 cut is small..can be seen in cbar
NEWOLD
Change of alphas does affect cbar slightly– it is now dynamically generated from the gluon!