Weighting di boson mc events gideon bella tel aviv university
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Weighting Di-Boson MC events Gideon Bella Tel Aviv University. MC generators Di-Boson processes Event weighting package Boson spin information Anomalous Triple Gauge Couplings (TGC) See: arXiv:0803.3307 (hep-ph). MC Generators. Di-Boson Processes.

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Weighting Di-Boson MC events Gideon Bella Tel Aviv University

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Weighting di boson mc events gideon bella tel aviv university

Weighting Di-Boson MC eventsGideon BellaTel Aviv University

  • MC generators

  • Di-Boson processes

  • Event weighting package

  • Boson spin information

  • Anomalous Triple Gauge Couplings (TGC)

    See: arXiv:0803.3307 (hep-ph)

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Mc generators

MC Generators

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Weighting di boson mc events gideon bella tel aviv university

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Di boson processes

Di-Boson Processes

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Weighting di boson mc events gideon bella tel aviv university

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Fraction of events with jet

Fraction of Events with Jet ( )

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Fraction of g q q jets

Fraction of g,q,q Jets ( )

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Event weighting package

Event Weighting Package

To introduce spin information to [email protected] generated events we assign each event with a weight:

The BHO weight calculation is done in the package bhowei which is based on the BHO code.

The BHO code requires the event to be balanced with conserved energy and momentum.

[email protected] events with or without ME jets are not balanced, due to the showering. SH jets show up as missing .

SH jets must be combined to the ME jets into one jet, to make the di-boson+jet system balanced.

We assume no longitudinal component of the SH jet in the c.m. frame.

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Weighting di boson mc events gideon bella tel aviv university

The resulting balanced event is interpreted as a di-boson+1jet event, and is handled by the BHO code as such, and the corresponding weight is always positive!

The event weighting package can be used also to introduce anomalous TGC to events generated by [email protected] , Pythia or Sherpa.

Another use is for systematic studies, e.g. PDF systematics, running the code for different PDFs.

Unfortunately, finite boson width cannot be introduced by event weighting.

The calling sequence:

call bhowei(mspin,xsec,ifail)

input: mspin=0 or 1 without/with spin info

output: xsec - resulting BHO cross-section (arbitrary units)

ifail – 0 for successful calculation

Additional information (event 4-momenta and particle id’s, physical constants, anomalous couplings, PDF set number) is entered via common blocks.

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Weighting di boson mc events gideon bella tel aviv university

Weights calculated by bhowei

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Boson spin information

q’

q

Boson Spin Information

Consider event:

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Weighting di boson mc events gideon bella tel aviv university

Are the differences for high PT(jet) related to the different contributions to jet events and different jet PT spectra?

We reweight BHO events, so that their jet info agrees with [email protected]

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Anomalous tgcs

Anomalous TGCs

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Summary and conclusions

Summary and Conclusions

  • Bhowei can be used to introduce:

    a) spin info to events generated by [email protected]

    b) TGC weights to events generated by [email protected] and Pythia

  • The hadronic system recoiling against the two bosons is different between different MC generators, causing differences in the angular and PT distributions of events with high PT(jet).

  • Events with high PT(jet) should be suppressed

  • Real data should be used to study events with high PT(jet).

  • Better di-boson MC generators are welcome:

    a) NLO+PS with spin information

    b) finite W and Z widths.

    c) anomalous couplings

    d) NNLO and electroweak corrections.

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Backup slides

Backup Slides

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Total cross sections pb multiplied by br into e

Total Cross Sections [pb]multiplied by BR into e+μ ( )

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Weighting di boson mc events gideon bella tel aviv university

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Weighting di boson mc events gideon bella tel aviv university

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Weighting di boson mc events gideon bella tel aviv university

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Weighting di boson mc events gideon bella tel aviv university

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