Whizard2 Generator
Tests
Layout
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Whizard2 event structure checks
Whizard2 , Whizard1 comparison
Circe2 beam parametrization tests
Whizard2 beam spectrum tests
Summary
17 November 2015
J-J.Blaising, LAPP/IN2P3
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Whizard2/Whizard1
Current CLICdp studies are done using Whizard1 event
generator with beam spectrum parametrization of Tim
Barklow.
Whizard2 includes new BSM processes; for future studies
we plan to use Whizard2.
Whizard2 tests were done for:
e⁺ e⁻ -> l⁺ l⁻ (e, μ, τ) and e⁺ e⁻ -> W⁺ W⁻ e⁺ e⁻ -> W⁺ W⁻ Z
• Parent <-> Daughter relation: Ok
• E, P conservation: Ok
Whizard2/Whizard1 comparison:
dN/d√s for incoming e⁺ e⁻ after ISR or Beamstrahlung.
dN/dP, dN/dθ for outgoing leptons or quarks
17 November 2015
J-J.Blaising, LAPP/IN2P3
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Whizard2/Whizard1 ISR
Left: dN/d√s: e⁺e⁻ -> μ⁺μ⁻ ISR good agreement over full √s range
Righg: dN/d√s e⁺e⁻ -> μ⁺μ⁻ ISR+Recoil disagreement in low √s range.
Origin? Under investigation by Whizard authors
Same for e, e and τ τ final states.
17 November 2015
J-J.Blaising, LAPP/IN2P3
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Whizard2/Whizard1
Left: dN/d√s e⁺e⁻ -> W⁺W⁻ ISR good agreement over √s range
Righg: dN/d√s e⁺e⁻ -> μ⁺μ⁻ ISR+Recoil agreement over √s range.
Same for ZZ, WWZ final states
Good agreement also for dN/dP and dN/dθ distributions.
17 November 2015
J-J.Blaising, LAPP/IN2P3
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Whizard2/Whizard1 (BS)
Left: dN/d√s: e⁺e⁻ -> μ⁺μ⁻ ,Beamstrahlung only, Wh1 (blue), σ=56 fb;
Wh2GP(red); σ=29 fb. The discrepancy is likely due to the Wh1 beam
spectrum. Right: dN/√s of unit ME events, Wh1 has a tail down to
low √s which is not in GP events.
σ( e⁺e⁻ -> μ⁺μ⁻ at √s=Mz)= 1.49E+06 fb; factor ~ E=+05 => Mz events
generated
in Wh1 and not inJ-J.Blaising,
Wh2 LAPP/IN2P3
17 November 2015
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Circe2
Beam Spectrum
Whizard2 events can be generated reading Guinea-pig
events or using the Circe2 parametrization of the GuineaPig events. For event generation on the grid, Circe2 beam
spectrum parametrization may be more convenient. =>
Check that event generation using Circe2 parametrization
gives same results as reading Guinea-pig events, (Thorston
Ohl Circe2 event generator) .
Whizard1 and Guinea-pig beam spectrum -> next slide
17 November 2015
J-J.Blaising, LAPP/IN2P3
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Whizard1
Beam Spectrum vs Guinea-pig
dN/√s distribution, Guinea-pig (blue)
Wh1 unit ME process e1e1_t (red);
at 3, 1.4 and 0.5 TeV
Reasonable agreement with Guineapig events in the peak region, 1.4TeV?
not for low values of √s
17 November 2015
J-J.Blaising, LAPP/IN2P3
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Circe2
Parametrization
Circe2 allows to describe distributions which contain singularities
and δ distributions or resonances.
Different functions mapping to the x1, x2 range of each beam are
available; xi=Ei/0.5√s
• Id { n [xmin, xmax] } identity mapping in the interval xmin , xmax
subdivided into n bins. ~ Tim’s parametrization.
• Power function {n [xmin,xmax] , β, η } mapping in the interval
xmin , xmax subdivided into n bins;
β = power of the function describing the singularity
η = position of the singularity
For the Math details, see Circe2 document, ???, but it works.
17 November 2015
J-J.Blaising, LAPP/IN2P3
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Circe2
Beam Spectrum 3TeV
Left: dN/√s distribution Guinea-pig (blue) and Circe2 using an Id
mapping (red); Right: ratio GP/Circe2.
Good agreement with Guinea-pig events in a large range, but not
for lower values of √s. ~ Tim’s parametrization (slide7).
17 November 2015
J-J.Blaising, LAPP/IN2P3
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Circe2
Beam Spectrum 3TeV
Left: dN/√s distribution Guinea-pig (blue) and Circe2 using a Power
function mapping (red); Right: ratio GP/Circe2.
Good agreement with Guinea-pig events in the whole √s range,
17 November 2015
J-J.Blaising, LAPP/IN2P3
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Guinea-pig, Circe2
2D Beam Spectrum 3TeV
Left : dE1 vs dE2 distribution Guinea-pig events;
Right: dE1 vs dE2 distribution Circe2 events
Circe2 reproduces well the different beam regions; peak, arms, tail.
17 November 2015
J-J.Blaising, LAPP/IN2P3
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Guinea-pig, Circe2
2D Beam Spectrum 3TeV
Left : dE1 vs dE2 Guinea-pig events
Right: dE1 vs dE2 Circe2 events
View focusing on peak and arms.
17 November 2015
J-J.Blaising, LAPP/IN2P3
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Circe2
Beam Spectrum 1.4 TeV
Left: dN/√s distribution Guinea-pig (blue) and Circe2 using an Id
mapping (red); Right: ratio GP/Circe2.
Good agreement with Guinea-pig events in a large range, but not
for lower values of √s. ~ Tim’s parametrization.
17 November 2015
J-J.Blaising, LAPP/IN2P3
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Circe2
Beam Spectrum 1.4 TeV
Left: dN/√s distribution Guinea-pig (blue) and Circe2 using a Power
function mapping (red); Right: ratio GP/Circe2.
Good agreement with Guinea-pig events in the whole √s range,
17 November 2015
J-J.Blaising, LAPP/IN2P3
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Circe2
Beam Spectrum 0.5 TeV
Left:dN/√s distribution Guinea-pig (blue) and Circe2 using an Id
mapping (red); Good agreement with Guinea-pig events in a large
range, but not for lower values of √s.
Right:dN/d√s distribution GP (blue),Wh1 Tim’s parametrization (red)
Slightly
better in low √s region.
17 November 2015
J-J.Blaising, LAPP/IN2P3
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Circe2
Beam Spectrum 0.5 TeV
Left: dN/√s distribution Guinea-pig (blue) and Circe2 using a Power
function mapping (red); Right: ratio GP/Circe2.
Good agreement with Guinea-pig events in the whole √s range =>
At all 3 energies Circe2 gives very good parametrization of the beam
17 November 2015
J-J.Blaising, LAPP/IN2P3
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Whizard2/ GP
Beam Spectrum 3 TeV
Next: Check that Whizard2, without physics process, reading Guineapig events reproduces the Guinea-pig spectrum.
Use process=$method = "template_unity“ ~ e1e1_t in Wh1.
Left: dN/√s distribution Guinea-pig (blue), Wh2GP(red)
Whizard2 seems to introduce a 1/s dependence; not in Wh1 (Right)
17 November 2015
J-J.Blaising, LAPP/IN2P3
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Whizard2
Beam Spectrum 3 TeV
Check:
Wh2 Guinea-pig e⁺e⁻ -> μ⁺μ⁻ dN/√s distribution (blue);
Wh2 GP template_unit dN/d√s distribution (red).
The template_unit process has a non expected 1/s dependence
Waiting
feedback from Whizard
authors.
17 November 2015
J-J.Blaising, LAPP/IN2P3
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Summary
• Whizard2 event structure is fine.
• Whizard2 and Whizard1 dN/d√s distributions agree, for
ISR events.
• For ISR+Recoil and lepton final states there is some
discrepancy at low values of √s.
• Circe2 beam spectrum parametrization gives a good
description of CLIC beam spectrum at all energies and is
adequate for Whizard2 event generation.
• Need still understand why template processes has 1/s
dependence.
Whizard2 is not far from production status.
Suggestions for additional tests are welcome.
17 November 2015
J-J.Blaising, LAPP/IN2P3
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