Top Physics in WHIZARD

Transcription

Top Physics in WHIZARD
Top Physics in WHIZARD
(+ NLO/QCD Status)
Jürgen R. Reuter, DESY
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
WHIZARD @
WHISTLER
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
My tribute to Canada …
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
My tribute to Canada …
✦
J.R.Reuter
in memoriam ✦
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
My tribute to Canada …
✦
in memoriam ✦
Jon Vickers, 29.10.1926 - 10.7.2015
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
“Vergeh’ die Welt
meiner jauchzenden Eil’!
Die Leuchte verlischt, zu ihr!
Isolde!”
LCWS 2015, Whistler, 4.11.15
WHIZARD: Overview
WHIZARD v2.2.7
(11.08.2015)
http://whizard.hepforge.org
<whizard@desy.de>
WHIZARD Team: Wolfgang Kilian,Thorsten Ohl, JRR
Simon Braß/Bijan Chokoufé/Marco Sekulla/Christian Weiss/Soyoung Shim/Florian Staub/Zhijie Zhao + 2 Master
(some losses: C. Speckner [software engineering], F. Bach [European Commission], S. Schmidt [Philosophy])
Publication: EPJ C71 (2011) 1742 (and others for O’Mega, Interfaces, color flow formalism)
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
WHIZARD: Overview
WHIZARD v2.2.7
(11.08.2015)
http://whizard.hepforge.org
<whizard@desy.de>
WHIZARD Team: Wolfgang Kilian,Thorsten Ohl, JRR
Simon Braß/Bijan Chokoufé/Marco Sekulla/Christian Weiss/Soyoung Shim/Florian Staub/Zhijie Zhao + 2 Master
(some losses: C. Speckner [software engineering], F. Bach [European Commission], S. Schmidt [Philosophy])
Publication: EPJ C71 (2011) 1742 (and others for O’Mega, Interfaces, color flow formalism)
LHC
2nd WHIZARD Workshop Würzburg, 03/2015
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
K. Desch, DESY Th-WS ‘15
LCWS 2015, Whistler, 4.11.15
WHIZARD Parton Shower
Two independent implementations: kT-ordered QCD and Analytic QCD shower
Analytic shower: no shower veto exact shower history known, allows reweighting
Kilian/JRR/Schmidt/Wiesler, JHEP 1204 013 (2012)
Technical overhaul of the shower / merging part
Plans: implement GKS matching, QED shower (also interleaved, infrastructure ready)
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
Tuning of the WHIZARD Parton Shower
First tunes of both kT-ordered QCD and Analytic QCD shower Chokoufe/Englert/JRR,
Di- and Multijet data from LEP as given in RIVET analysis
Usage of the PROFESSOR tool for determining the best fit Buckley et al., 2009
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
2015
LCWS 2015, Whistler, 4.11.15
NLO Development in WHIZARD
Need for precision predictions that match (sub-) percent experimental accuracy
mainly NLO corrections, but also QED and electroweak (ee)
Binoth Les Houches Interface (BLHA): Workflow
1. Process definition in SINDARIN (contract to One-Loop Program [OLP])
2. OLP generates code (Born/virtual interference), WHIZARD reads contract
3. NLO matrix element library loaded into WHIZARD
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
NLO Development in WHIZARD
Need for precision predictions that match (sub-) percent experimental accuracy
mainly NLO corrections, but also QED and electroweak (ee)
Binoth Les Houches Interface (BLHA): Workflow
1. Process definition in SINDARIN (contract to One-Loop Program [OLP])
2. OLP generates code (Born/virtual interference), WHIZARD reads contract
3. NLO matrix element library loaded into WHIZARD
Working NLO interfaces to:
(first focus on QCD corrections)
J.R.Reuter
GoSam
[G. Cullen et al.]
OpenLoops [F. Cascioli et al.]
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
NLO Development in WHIZARD
Need for precision predictions that match (sub-) percent experimental accuracy
mainly NLO corrections, but also QED and electroweak (ee)
Binoth Les Houches Interface (BLHA): Workflow
1. Process definition in SINDARIN (contract to One-Loop Program [OLP])
2. OLP generates code (Born/virtual interference), WHIZARD reads contract
3. NLO matrix element library loaded into WHIZARD
Working NLO interfaces to:
(first focus on QCD corrections)
GoSam
[G. Cullen et al.]
OpenLoops [F. Cascioli et al.]
WHIZARD v2.2.6 contains alpha version
QCD corrections (massless and massive emitters)
alpha_power = 2
alphas_power = 0
process eett = e1,E1 => t, tbar
{ nlo_calculation = “full” }
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
NLO Development in WHIZARD
Need for precision predictions that match (sub-) percent experimental accuracy
mainly NLO corrections, but also QED and electroweak (ee)
Binoth Les Houches Interface (BLHA): Workflow
1. Process definition in SINDARIN (contract to One-Loop Program [OLP])
2. OLP generates code (Born/virtual interference), WHIZARD reads contract
3. NLO matrix element library loaded into WHIZARD
Working NLO interfaces to:
(first focus on QCD corrections)
GoSam
[G. Cullen et al.]
OpenLoops [F. Cascioli et al.]
WHIZARD v2.2.6 contains alpha version
QCD corrections (massless and massive emitters)
alpha_power = 2
alphas_power = 0
process eett = e1,E1 => t, tbar
{ nlo_calculation = “full” }
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
NLO Development in WHIZARD
Need for precision predictions that match (sub-) percent experimental accuracy
mainly NLO corrections, but also QED and electroweak (ee)
Binoth Les Houches Interface (BLHA): Workflow
1. Process definition in SINDARIN (contract to One-Loop Program [OLP])
2. OLP generates code (Born/virtual interference), WHIZARD reads contract
3. NLO matrix element library loaded into WHIZARD
Working NLO interfaces to:
(first focus on QCD corrections)
GoSam
[G. Cullen et al.]
OpenLoops [F. Cascioli et al.]
fixedorder
1000
WHIZARD v2.2.6 contains alpha version
800
QCD corrections (massless and massive emitters)
[fb]
600
alpha_power = 2
alphas_power = 0
400
process eett = e1,E1 => t, tbar
{ nlo_calculation = “full” }
200
onshell, LO
onshell, NLO
offshell, LO
offshell, NLO
0
350
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
400
450
p
500
550
600
s [GeV]
LCWS 2015, Whistler, 4.11.15
FKS Subtraction
(Frixione/Kunszt/Signer)
Subtraction formalism to make real and virtual contributions separately finite
d
NLO
=
Z
|
J.R.Reuter
d
n+1
R
{z
finite
d
S
+
}
Z
|
d
n+1
S
+
{z
finite
Top Physics in WHIZARD (+NLO/QCD)
Z
d
n
V
}
LCWS 2015, Whistler, 4.11.15
FKS Subtraction
(Frixione/Kunszt/Signer)
Subtraction formalism to make real and virtual contributions separately finite
d
NLO
=
Z
|
d
n+1
R
d
S
{z
+
}
finite
✴
Z
|
d
n+1
S
+
{z
Z
d
n
finite
V
}
Automated subtraction terms in WHIZARD,
algorithm:
Find all singular pairs
I = {(1, 5), (1, 6), (2, 5), (2, 6), (5, 6)}
✴
Partition phase space according to singular regions
1=
X
S↵ ( )
↵2I
✴
J.R.Reuter
Generate subtraction terms for singular regions
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
FKS Subtraction
(Frixione/Kunszt/Signer)
Subtraction formalism to make real and virtual contributions separately finite
d
NLO
=
Z
|
d
n+1
R
d
S
{z
+
}
finite
✴
Z
|
d
n+1
S
+
{z
Z
d
n
finite
V
}
Automated subtraction terms in WHIZARD,
algorithm:
Find all singular pairs
I = {(1, 5), (1, 6), (2, 5), (2, 6), (5, 6)}
✴
Partition phase space according to singular regions
1=
X
S↵ ( )
↵2I
✴
J.R.Reuter
Generate subtraction terms for singular regions
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
Examples and Validation
Simplest benchmark process:
e+ e ! q q̄
with
NLO
LO
/
LO
= ↵s /⇡
Plot for total cross section for fixed
strong coupling constant
List of validated QCD NLO processes
•
e+ e ! q q̄
•
e+ e ! q q̄g
•
e+ e ! `+ ` q q̄
• Cross-checks with MG5_aMC@NLO
•
e+ e ! `+ ⌫` q q̄
• Phase space integration for virtuals performs great
•
e+ e ! tt̄
•
e+ e ! tW b
•
e+ e ! W + W bb̄
•
e+ e ! tt̄H
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
Examples and Validation
Simplest benchmark process:
e+ e ! q q̄
with
NLO
LO
/
LO
= ↵s /⇡
Plot for total cross section for fixed
strong coupling constant
List of validated QCD NLO processes
•
e+ e ! q q̄
•
e+ e ! q q̄g
•
e+ e ! `+ ` q q̄
• Cross-checks with MG5_aMC@NLO
•
e+ e ! `+ ⌫` q q̄
• Phase space integration for virtuals performs great
•
e+ e ! tt̄
•
e+ e ! tW b
✦
QCD NLO infrastructure in pp complete
•
e+ e ! W + W bb̄
✦
•
e+ e ! tt̄H
First attempts on electroweak corrections,
interfacing the RECOLA code [Denner et al.]
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
NLO Fixed-Order Events
Add weights of real emission events to weight of Born kinematics using the FKS mapping
Output weighted events in WHIZARD (e.g. using HepMC), then analysis with Rivet
Example process: e+ e ! W + W bb̄
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
NLO Fixed-Order Events
Add weights of real emission events to weight of Born kinematics using the FKS mapping
Output weighted events in WHIZARD (e.g. using HepMC), then analysis with Rivet
Example process: e+ e ! W + W bb̄
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
NLO Fixed-Order Events
Add weights of real emission events to weight of Born kinematics using the FKS mapping
Output weighted events in WHIZARD (e.g. using HepMC), then analysis with Rivet
Example process: e+ e ! W + W bb̄
Completed: polarized NLO results (remember: ILC will always run with polarization)
Produce also plots including complete ISR photon radiation and beamstrahlung
NLO decays also available (Initial state Jacobian, important for consistent widths)
Investigate the full 2 ➝ 6 process: e+e- ➝ bbeμνν
[Chokoufé/Kilian/Lindert/JRR/Pozzorini/Weiss]
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
Automated POWHEG Matching in WHIZARD
Soft gluon emissions before hard emission generate large logs
1
kTmax
2
Perturbative αs : |Msoft | ⇠ k2 ! log kmin
T
T
Consistent matching of NLO matrix element with shower
POWHEG method: hardest emission first [Nason et al.]
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
Automated POWHEG Matching in WHIZARD
Soft gluon emissions before hard emission generate large logs
1
kTmax
2
Perturbative αs : |Msoft | ⇠ k2 ! log kmin
T
T
Consistent matching of NLO matrix element with shower
POWHEG method: hardest emission first [Nason et al.]
• Complete NLO events
B(
n)
= B(
n)
+V(
n)
• POWHEG generate events according to the formula:
d = B(
n)

NLO min
(kT )
R
• Uses the modified Sudakov form factor:
 Z
NLO
(kT ) = exp
d
R
J.R.Reuter
+
+
Z
d
rad R(
R(
NLO
(kT )
R
R( n+1 )
✓(kT (
rad
B( n )
Top Physics in WHIZARD (+NLO/QCD)
n+1 )
n+1 )
B(
n)
n+1 )
d
rad
kT )
LCWS 2015, Whistler, 4.11.15
Automated POWHEG Matching in WHIZARD
Soft gluon emissions before hard emission generate large logs
1
kTmax
2
Perturbative αs : |Msoft | ⇠ k2 ! log kmin
T
T
Consistent matching of NLO matrix element with shower
POWHEG method: hardest emission first [Nason et al.]
• Complete NLO events
B(
n)
= B(
n)
+V(
n)
• POWHEG generate events according to the formula:
d = B(
n)

NLO min
(kT )
R
• Uses the modified Sudakov form factor:
 Z
NLO
(kT ) = exp
d
R
+
+
Z
d
rad R(
R(
NLO
(kT )
R
R( n+1 )
✓(kT (
rad
B( n )
n+1 )
n+1 )
B(
n)
n+1 )
d
rad
kT )
Hardest emission: kTmax ; shower with imposing a veto
B < 0 if virtual and real terms larger than Born: shouldn’t happen in perturbative regions
Reweighting such that B > 0 for all events
POWHEG: Positive Weight Hardest Emission Generator own implementation in WHIZARD
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
POWHEG Matching, example: e+e- to dijets
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
Examples: Top pairs and tth production
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
Top Threshold at lepton colliders
ILC top threshold scan best-known method to measure top quark mass, ΔΜ ~ 30-50 MeV
Heavy quark production at lepton colliders, qualitatively:
Threshold region: top velocity v ~ αs ⪡ 1
J.R.Reuter
⌫=
rp
s
Top Physics in WHIZARD (+NLO/QCD)
2mt + i
m
t
LCWS 2015, Whistler, 4.11.15
Top Threshold Resummation in (p)NRQCD
NRQCD is EFT for non-relativistic quark-antiquark systems: separate M·v and M·v 2
Integrate out hard quark and gluon d.o.f.
Resummation of singular terms close to threshold (v = 0) Hoang et al. ’99-‘01; Beneke et al., ’13-‘14
Phase space of two massive particles
R⌘
tt̄
µµ
=v
X ⇣ ↵ s ⌘k X
k
v
i
i
(↵s ln v) ⇥
⇥ 1 (LL); ↵s , v (NLL); ↵s2 , ↵s v, v 2 (NNLL)
(p/v)NRQCD EFT w/ RG improvement
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
Top Threshold Resummation in (p)NRQCD
NRQCD is EFT for non-relativistic quark-antiquark systems: separate M·v and M·v 2
Integrate out hard quark and gluon d.o.f.
Resummation of singular terms close to threshold (v = 0) Hoang et al. ’99-‘01; Beneke et al., ’13-‘14
Phase space of two massive particles
R⌘
tt̄
=v
µµ
X ⇣ ↵ s ⌘k X
k
v
i
i
(↵s ln v) ⇥
⇥ 1 (LL); ↵s , v (NLL); ↵s2 , ↵s v, v 2 (NNLL)
R
,Z
v
v
a
a
(p/v)NRQCD EFT w/ RG improvement
(s) = F (s)R (s) + F (s)R (s)
|
{z
}
|
{z
}
s-wave: LL+NLL
p-wave⇠v 2 :NNLL
but contributes
at NLL differentially!
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
Top Threshold Resummation in (p)NRQCD
NRQCD is EFT for non-relativistic quark-antiquark systems: separate M·v and M·v 2
Integrate out hard quark and gluon d.o.f.
Resummation of singular terms close to threshold (v = 0) Hoang et al. ’99-‘01; Beneke et al., ’13-‘14
Phase space of two massive particles
R⌘
tt̄
=v
µµ
X ⇣ ↵ s ⌘k X
k
v
i
i
(↵s ln v) ⇥
⇥ 1 (LL); ↵s , v (NLL); ↵s2 , ↵s v, v 2 (NNLL)
R
,Z
v
v
a
a
(p/v)NRQCD EFT w/ RG improvement
(s) = F (s)R (s) + F (s)R (s)
|
{z
}
|
{z
}
s-wave: LL+NLL
p-wave⇠v 2 :NNLL
but contributes
at NLL differentially!
Coulomb potential gluon ladder resumption
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
Top Threshold Resummation in (p)NRQCD
NRQCD is EFT for non-relativistic quark-antiquark systems: separate M·v and M·v 2
Integrate out hard quark and gluon d.o.f.
Resummation of singular terms close to threshold (v = 0) Hoang et al. ’99-‘01; Beneke et al., ’13-‘14
Phase space of two massive particles
R⌘
tt̄
=v
µµ
X ⇣ ↵ s ⌘k X
k
v
i
i
(↵s ln v) ⇥
⇥ 1 (LL); ↵s , v (NLL); ↵s2 , ↵s v, v 2 (NNLL)
R
,Z
v
v
a
|
a
(s) = F (s)R (s) + F (s)R (s)
|
{z
}
|
{z
}
s-wave: LL+NLL
{z
}
(p/v)NRQCD EFT w/ RG improvement
can be mapped onto effective ttV vertex
p-wave⇠v 2 :NNLL
but contributes
at NLL differentially!
Coulomb potential gluon ladder resumption
far away from
threshold
C3
J.R.Reuter
v/a
G(N)LL
=
v/a
pole p
G(N)LL (↵s , Mt , s, |~
pt | ,
t)
differential in off-shell tt phase space
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
Top Threshold in WHIZARD
with F. Bach/B. Chokoufe/A. Hoang/M. Stahlhofen/C. Weiss
Implement resummed threshold effects as effective vertex [form factor] in WHIZARD
Gv,a (0, pt , E + i t , ⌫) from TOPPIK code [Jezabek/Teubner], included in WHIZARD
Default parameters:
M 1S = 172 GeV,
M 1S = Mtpole (1
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
NLO
t
= 1.409 GeV
↵s (MZ ) = 0.118
LL/N LL
(Coul.) )
[P. Marquard’s talk]
LCWS 2015, Whistler, 4.11.15
Top Threshold in WHIZARD
with F. Bach/B. Chokoufe/A. Hoang/M. Stahlhofen/C. Weiss
Implement resummed threshold effects as effective vertex [form factor] in WHIZARD
Gv,a (0, pt , E + i t , ⌫) from TOPPIK code [Jezabek/Teubner], included in WHIZARD
Default parameters:
M 1S = 172 GeV,
M 1S = Mtpole (1
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
NLO
t
= 1.409 GeV
↵s (MZ ) = 0.118
LL/N LL
(Coul.) )
[P. Marquard’s talk]
LCWS 2015, Whistler, 4.11.15
Top Threshold in WHIZARD
with F. Bach/B. Chokoufe/A. Hoang/M. Stahlhofen/C. Weiss
Implement resummed threshold effects as effective vertex [form factor] in WHIZARD
Gv,a (0, pt , E + i t , ⌫) from TOPPIK code [Jezabek/Teubner], included in WHIZARD
Default parameters:
M 1S = 172 GeV,
NLO
t
= 1.409 GeV
↵s (MZ ) = 0.118
LL/N LL
(Coul.) )
M 1S = Mtpole (1
[P. Marquard’s talk]
Theory uncertainties from scale variations:
hard and soft scale
µh = h · mt
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
µ s = f · mt v
LCWS 2015, Whistler, 4.11.15
Sanity checks: correct limit for αs ⟶ 0, stable against variation of cutoff ΔM [15-30 GeV]
Why include LL/NLL in a Monte Carlo event generator?
Important effects: beamstrahlung; ISR; LO electroweak terms
More exclusive observables accessible
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
Sanity checks: correct limit for αs ⟶ 0, stable against variation of cutoff ΔM [15-30 GeV]
Why include LL/NLL in a Monte Carlo event generator?
Important effects: beamstrahlung; ISR; LO electroweak terms
More exclusive observables accessible
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
Sanity checks: correct limit for αs ⟶ 0, stable against variation of cutoff ΔM [15-30 GeV]
Why include LL/NLL in a Monte Carlo event generator?
Important effects: beamstrahlung; ISR; LO electroweak terms
More exclusive observables accessible
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
Forward-backward asymmetry
(norm. good shape stability)
Af b :=
(ptz > 0)
(ptz ) < 0)
(ptz > 0) + (ptz < 0)
LCWS 2015, Whistler, 4.11.15
Matching to continuum at LO and NLO
analytic+whizard-onshell
1000
800
600
[fb]
• Transition region between relativistic and
resummation effects
• CLIC benchmark energies:
0.38 TeV, 1.4 TeV, 3.0 TeV
• Remove double-counting NLO / (N)LL
400
200
onshell, NLO
expanded FF, onshell, mpole = m1S
expanded FF, onshell, mpole = m1S , nopwave
AnalyticOneloop, mpole = m1S , onshell
0
340
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
350
360
p
370
s [GeV]
380
390
400
LCWS 2015, Whistler, 4.11.15
Matching to continuum at LO and NLO
analytic+whizard-onshell
• Transition region between relativistic and
resummation effects
• CLIC benchmark energies:
0.38 TeV, 1.4 TeV, 3.0 TeV
• Remove double-counting NLO / (N)LL
1000
1000
onshell, NLO
expanded FF, onshell, mpole = m1S
expanded FF, onshell, mpole = m1S , nopwave
AnalyticOneloop, mpole = m1S , onshell
800
800
[fb]
[fb]
600
600
400
400
Resummed formfactor, expanded to O(↵s )
rp
s 2mt + i t
⌫=
p = |~
p|
p0 = E t
m
J.R.Reuter
200
200
mt
Top Physics in WHIZARD (+NLO/QCD)
onshell, NLO
expanded FF, onshell, mpole = m1S
expanded FF, onshell, mpole = m1S , nopwave
AnalyticOneloop, mpole = m1S , onshell
00
344.0
340
350 344.5 360
345.0
p 370
s [GeV]
380 345.5 390
346.0
400
LCWS 2015, Whistler, 4.11.15
Matching to continuum at LO and NLO
analytic+whizard-onshell
• Transition region between relativistic and
resummation effects
• CLIC benchmark energies:
0.38 TeV, 1.4 TeV, 3.0 TeV
• Remove double-counting NLO / (N)LL
1000
1000
onshell, NLO
expanded FF, onshell, mpole = m1S
expanded FF, onshell, mpole = m1S , nopwave
AnalyticOneloop, mpole = m1S , onshell
800
800
[fb]
[fb]
600
600
400
400
Resummed formfactor, expanded to O(↵s )
rp
s 2mt + i t
⌫=
p = |~
p|
p0 = E t
m
200
200
mt
onshell, NLO
expanded FF, onshell, mpole = m1S
expanded FF, onshell, mpole = m1S , nopwave
AnalyticOneloop, mpole = m1S , onshell
00
344.0
340
350 344.5 360
345.0
p 370
s [GeV]
380 345.5 390
346.0
400
Matching formula
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
Matching to continuum at LO and NLO
analytic+whizard-onshell
• Transition region between relativistic and
resummation effects
• CLIC benchmark energies:
0.38 TeV, 1.4 TeV, 3.0 TeV
• Remove double-counting NLO / (N)LL
1000
1000
onshell, NLO
expanded FF, onshell, mpole = m1S
expanded FF, onshell, mpole = m1S , nopwave
AnalyticOneloop, mpole = m1S , onshell
800
800
[fb]
[fb]
600
600
400
400
Resummed formfactor, expanded to O(↵s )
rp
s 2mt + i t
⌫=
p = |~
p|
p0 = E t
m
200
200
mt
Matching formula
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
onshell, NLO
expanded FF, onshell, mpole = m1S
expanded FF, onshell, mpole = m1S , nopwave
AnalyticOneloop, mpole = m1S , onshell
00
344.0
340
350 344.5 360
345.0
p 370
s [GeV]
380 345.5 390
346.0
400
Switch-off function
LCWS 2015, Whistler, 4.11.15
Threshold-continuum matching
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
Conclusions & Outlook
WHIZARD 2.2 event generator for collider physics (ee, pp, ep)
Focus here on top physics at ee colliders
(QCD) NLO automation: reals and subtraction terms (FKS) [+
virtuals externally] ➝ WHIZARD 3.0
Automated POWHEG matching (other schemes in progress)
Polarized results and decays available at NLO (QCD)
Top threshold in e+e-: NLL NRQCD threshold / NLO
continuum matching
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
Conclusions & Outlook
WHIZARD 2.2 event generator for collider physics (ee, pp, ep)
Focus here on top physics at ee colliders
(QCD) NLO automation: reals and subtraction terms (FKS) [+
virtuals externally] ➝ WHIZARD 3.0
Automated POWHEG matching (other schemes in progress)
Polarized results and decays available at NLO (QCD)
Top threshold in e+e-: NLL NRQCD threshold / NLO
continuum matching
Future projects: inclusion of tth threshold
Long term: QED/EW NLO, QED Shower, NNLO QCD
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
Conclusions & Outlook
WHIZARD 2.2 event generator for collider physics (ee, pp, ep)
Focus here on top physics at ee colliders
(QCD) NLO automation: reals and subtraction terms (FKS) [+
virtuals externally] ➝ WHIZARD 3.0
Automated POWHEG matching (other schemes in progress)
Polarized results and decays available at NLO (QCD)
Top threshold in e+e-: NLL NRQCD threshold / NLO
continuum matching
Future projects: inclusion of tth threshold
Long term: QED/EW NLO, QED Shower, NNLO QCD
Experimentalists present !?!?
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
Conclusions & Outlook
WHIZARD 2.2 event generator for collider physics (ee, pp, ep)
Focus here on top physics at ee colliders
(QCD) NLO automation: reals and subtraction terms (FKS) [+
virtuals externally] ➝ WHIZARD 3.0
Automated POWHEG matching (other schemes in progress)
Polarized results and decays available at NLO (QCD)
Top threshold in e+e-: NLL NRQCD threshold / NLO
continuum matching
Future projects: inclusion of tth threshold
Long term: QED/EW NLO, QED Shower, NNLO QCD
Experimentalists present !?!?
J.R.Reuter
Time for the:
Experimentalists’ ILC/CLIC NLO Wishlist
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15
J.R.Reuter
Top Physics in WHIZARD (+NLO/QCD)
LCWS 2015, Whistler, 4.11.15