PELLEN mpi Munich 2021 · 2021. 1. 25. · 2) pp ! W+W j @ NLO QCD+EW with parton shower q q¯ e W ⌫¯ e µ+ W ⌫ µ g q g e W ⌫¯ e µ+ W ⌫ µ q Motivated by ATLAS measurement
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Theoretical calculationsfor phenomenology at the LHC
Mathieu PELLEN
University of Freiburg
Group Leader Position at the Max Planck Institute for Physics
Max Planck Institute for Physics, Germany
26th of January 2021
Legacy of the LHC:
4−10
3−10
2−10
1−10
1
10
210
310
410
510 [pb]
σPr
oduc
tion
Cro
ss S
ectio
n,
CMS PreliminarySeptember 2020
All results at: http://cern.ch/go/pNj7
W
n jet(s)≥
Z
n jet(s)≥
γW γZ WW WZ ZZ VVV WWW WWZ WZZ ZZZ γWV γγZ γγWµll, l=e,→, Zνl→: fiducial with Wγγ,WγγEW,Z
qqWEW qqZ
EWWW→γγ
γqqWEW
ssWW EW
γqqZEW
qqWZEW
qqZZEW tt
=n jet(s)
t-cht tW s-cht γtt tZq ttZ γt ttW ttttσ∆ in exp. Hσ∆Th.
ggHqqHVBF VH WH ZH ttH tH HH
CMS 95%CL limits at 7, 8 and 13 TeV
)-1 5.0 fb≤7 TeV CMS measurement (L )-1 19.6 fb≤8 TeV CMS measurement (L )-1 137 fb≤13 TeV CMS measurement (L
Theory prediction
Mathieu PELLEN Theoretical calculations for phenomenology at the LHC 2 / 22
Outline:
! Selection of ...
Physics results
source: ATLAS
Tools to obtain these results
source: www.nist.gov
! ... at the LHCMathieu PELLEN Theoretical calculations for phenomenology at the LHC 3 / 22
Exploring the Electroweak sectorof the Standard Model
pp ! W± + jc @ NNLO QCD
pp ! W+W�j @ NLO QCD+EW with parton shower
pp ! W±W±jj @ full NLO
Mathieu PELLEN Theoretical calculations for phenomenology at the LHC 4 / 22
1) pp ! W± + jc @ NNLO QCD
s̄
g
⌫µ
µ+
c̄
s
g
⌫̄µ
µ�
c
Direct link between W+c measurements and strange PDF
Study of flavour jets [Banfi, Salam, Zanderighi; hep-ph/0601139]
B First NNLO QCD computation of W+c-jet[Czakon, Mitov, MP, Poncelet; 2011.01011]
Mathieu PELLEN Theoretical calculations for phenomenology at the LHC 5 / 22
1) pp ! W± + jc @ NNLO QCD
s̄
g
⌫µ
µ+
c̄
s
g
⌫̄µ
µ�
c
Direct link between W+c measurements and strange PDF
Study of flavour jets [Banfi, Salam, Zanderighi; hep-ph/0601139]
B First NNLO QCD computation of W+c-jet[Czakon, Mitov, MP, Poncelet; 2011.01011]
Mathieu PELLEN Theoretical calculations for phenomenology at the LHC 5 / 22
1) pp ! W± + jc @ NNLO QCD
10 15 20 25 30 35 40 45 50 55
� [pb]
W�jc
W+jc
LHC 7 TeV PDF: NNPDF31 LONLO
NNLO
NNLO PDF unc.
ATLAS
0.80 0.85 0.90 0.95 1.00 1.05
RW±jc
[Czakon, Mitov, MP, Poncelet; 2011.01011]
Comparison against ATLAS data
Good overall agreementB PDF uncertainty dominant
Potential to improve understanding of strange within proton:! Strange asymmetry / Global PDF fit
Mathieu PELLEN Theoretical calculations for phenomenology at the LHC 6 / 22
2) pp ! W+W�j @ NLO QCD+EW with parton shower
q
q̄
e�
⌫̄eWµ+
⌫µW
g
q
g
e�
⌫̄eWµ+
⌫µW
q
Motivated by ATLAS measurement [1608.03086]
Search for anomalous triple gauge-boson couplings
Complementary to di-boson measurements! Similar e↵ect with di↵erent kinematic
Mathieu PELLEN Theoretical calculations for phenomenology at the LHC 7 / 22
2) pp ! W+W�j @ NLO QCD+EW with parton shower
q
q̄
e�
⌫̄eWµ+
⌫µW
g
q
g
e�
⌫̄eWµ+
⌫µW
q
Motivated by ATLAS measurement [1608.03086]
Search for anomalous triple gauge-boson couplings
Complementary to di-boson measurements! Similar e↵ect with di↵erent kinematic
Mathieu PELLEN Theoretical calculations for phenomenology at the LHC 7 / 22
2) pp ! W+W�j @ NLO QCD+EW with parton shower
njet = 1
She
rpa
+Re
co
la
MEPS@NLOpp ! µ+nµe�n̄epp ! + 0,1j@NLO + 2,3j@LO
LONLO QCDNLO QCD + EWapproxNLO QCD ⇥ EWapprox10
�2
10
�1
1
pp ! µ+nµe�n̄e + jets @ 13 TeV
ds/d
p T,j 1
[fb/
GeV
]
0 50 100 150 200 250 300 350 400
0.70.80.91.01.11.2
pT,j1 [GeV]
s/s
MEP
S@N
LOQ
CD
njet = 1
She
rpa
+Re
co
la
MEPS@NLO pp ! µ+nµe�n̄e + 0,1j@NLO + 2,3j@LO
LONLO QCD
NLO QCD + EWapproxNLO QCD ⇥ EWapprox
0
10
20
30
40
50
pp ! µ+nµe�n̄e + jets @ 13 TeVds
/dy j
1[f
b]
-2 -1 0 1 2
0.8
0.9
1.0
1.1
yj1
s/s
MEP
S@N
LOQ
CD
[Bräuer, Denner, MP, Schönherr, Schumann; 2011.01011]
Inclusion of EW e↵ects in NLO+Parton Shower simulation
Typical EW Sudakov logarithms
Mathieu PELLEN Theoretical calculations for phenomenology at the LHC 8 / 22
2) pp ! W+W�j @ NLO QCD+EW with parton shower
She
rpa
+Re
co
la
MEPS@NLO pp ! µ+nµe�n̄e + 0,1j@NLO + 2,3j@LO
LONLO QCD
NLO QCD + EWapproxNLO QCD ⇥ EWapprox
0
2
4
6
8
pp ! µ+nµe�n̄e + jets @ 13 TeV
R1j 0j
(pT,
mis
s)
0 50 100 150 200 250 300 350 400
0.9
1.0
1.1
pT,miss [GeV]
R1j 0j
/R
1j 0j,M
EPS@
NLO
QC
D
She
rpa
+Re
co
la
LONLO QCD
NLO QCD + EWapproxNLO QCD ⇥ EWapprox
MEPS@NLO pp ! µ+nµe�n̄e + 0,1j@NLO + 2,3j@LO
0.2
0.4
0.6
0.8
1
pp ! µ+nµe�n̄e + jets @ 13 TeV
R1j 0j
(Df
µ+
e�)
0 20 40 60 80 100 120 140 160 180
0.9
1.0
1.1
Dfµ+e� [�]
R1j 0j
/R
1j 0j,M
EPS@
NLO
QC
D
[Bräuer, Denner, MP, Schönherr, Schumann; 2011.01011]
Use of ratios WWj/WW! WW known up to NNLO + PS [Re, Wiesemann, Zanderighi; 1805.09857]! Cancellation of uncertainties! Sensitive probe of the Standard Model
Mathieu PELLEN Theoretical calculations for phenomenology at the LHC 9 / 22
3) pp ! W±W±jj @ full NLOVector-boson scattering and its background
W+
W+
H
u
d̄
d
ū
⌫ee+⌫µµ+
W+
W+
W+
W+
u
d̄
d
ū
⌫ee+⌫µµ+W
+
W+
u
d̄
g
d
ū
⌫ee+⌫µµ+
W+
W+
First full NLO computation for same-sign WW
B Already known:! approx. O(↵s↵6) [Jäger, Oleari, Zeppenfeld; 0907.0580], [Denner, Hošeková, Kallweit; 1209.2389]! O(↵3s↵4) [Melia, Melnikov, Röntsch, Zanderighi], [Campanario, Kerner, Ninh, Zeppenfeld; 1311.6738]
Mathieu PELLEN Theoretical calculations for phenomenology at the LHC 10 / 22
3) pp ! W±W±jj @ full NLOVector-boson scattering and its background
W+
W+
H
u
d̄
d
ū
⌫ee+⌫µµ+
W+
W+
W+
W+
u
d̄
d
ū
⌫ee+⌫µµ+W
+
W+
u
d̄
g
d
ū
⌫ee+⌫µµ+
W+
W+
O�↵s↵5�O�↵6� O�↵2s↵4
�LO
O�↵7� O�↵s↵6� O�↵2s↵5
� O�↵3s↵4�
NLO
EW
QCD
EW
QCD
EW
QCD
First full NLO computation for same-sign WW
B Already known:! approx. O(↵s↵6) [Jäger, Oleari, Zeppenfeld; 0907.0580], [Denner, Hošeková, Kallweit; 1209.2389]! O(↵3s↵4) [Melia, Melnikov, Röntsch, Zanderighi], [Campanario, Kerner, Ninh, Zeppenfeld; 1311.6738]
Mathieu PELLEN Theoretical calculations for phenomenology at the LHC 10 / 22
3) pp ! W±W±jj @ full NLOVector-boson scattering and its background
W+
W+
H
u
d̄
d
ū
⌫ee+⌫µµ+
W+
W+
W+
W+
u
d̄
d
ū
⌫ee+⌫µµ+W
+
W+
u
d̄
g
d
ū
⌫ee+⌫µµ+
W+
W+
O�↵s↵5�O�↵6� O�↵2s↵4
�LO
O�↵7� O�↵s↵6� O�↵2s↵5
� O�↵3s↵4�
NLO
EW
QCD
EW
QCD
EW
QCD
First full NLO computation for same-sign WW
B Already known:! approx. O(↵s↵6) [Jäger, Oleari, Zeppenfeld; 0907.0580], [Denner, Hošeková, Kallweit; 1209.2389]! O(↵3s↵4) [Melia, Melnikov, Röntsch, Zanderighi], [Campanario, Kerner, Ninh, Zeppenfeld; 1311.6738]Mathieu PELLEN Theoretical calculations for phenomenology at the LHC 10 / 22
3) pp ! W±W±jj @ full NLO
10�5
10�4
10�3
-30-25-20-15-10-505
10
-3-2-10123
600 800 1000 1200 1400 1600 1800 2000
dsdM
j 1j 2
⇥fb GeV⇤
LO EWLO QCDLO INTNLO
d[%
]
a7 asa6 NLO
d[%
]
Mj1j2 [GeV]
a2s a5 a3s a4 photon a7
dsdM
j 1j 2
⇥fb GeV⇤
LONLO
10�3
d[%
]
Mj1j2 [GeV]
-30-25-20-15-10-505
1015
600 800 1000 1200 1400 1600 1800 2000
[Biedermann, Denner, MP; 1708.00268]
Di↵erent LO and NLO behavioursB Large EW corrections
Mathieu PELLEN Theoretical calculations for phenomenology at the LHC 11 / 22
3) pp ! W±W±jj @ full NLO! O(↵7) reproduced by Leading-Log approximation
�LL = �LO
1 �
↵
4⇡4CewW log
2
Q2
M2W
!+
↵
4⇡2bewW log
Q2
M2W
!�
C ew larger for bosons than fermionshm4`i larger for VBS (massive t-channel [Denner, Hahn; hep-ph/9711302])
! Large EW corrections: intrinsic feature of VBS at the LHC
ds dyj 1
j 2[fb
]
LONLO EW
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
d[%
]
yj1j2
NLO EW-20
-15
-10
-5
0
-3 -2 -1 0 1 2 3
[Biedermann, Denner, MP; 1611.02951]
Sensitive to EW corrections at High-Luminosity LHC
Mathieu PELLEN Theoretical calculations for phenomenology at the LHC 12 / 22
At the core of this work:Development of methods and tools
All LHC results are obtained with computer programs!
All cutting edge computations requires huge CPU resources
Automation necessary to cover all LHC physics
Programs are a way to communicate results! Golden standard: automatised and public tools!
Mathieu PELLEN Theoretical calculations for phenomenology at the LHC 13 / 22
At the core of this work:Development of methods and tools
All LHC results are obtained with computer programs!
All cutting edge computations requires huge CPU resources
Automation necessary to cover all LHC physics
Programs are a way to communicate results! Golden standard: automatised and public tools!
Mathieu PELLEN Theoretical calculations for phenomenology at the LHC 13 / 22
NLO QCD/EW corrections in POWHEG
! Implementation process by process in POWHEG[Alioli, Frixione, Ježo, Nason, Oleari, Re; hep-ph/0409146, 0709.2092, 1002.2581, 1509.09071]
1) Squark production and decay at NLO SUSY QCD[Gavin, Hangst, Krämer, Mühlleitner, MP, Popenda, Spira; 1305.4061, 1407.7971]
2) Same-sign W-boson scattering at NLO EW[Chiesa, Denner, Lang, MP; 1906.01863]
Work
Implementation of all partonic/decay channels
Implementation of necessary pieces! Matrix elements, colour-correlated matrix elements, etc.! Either own subroutines or automatised code
Mathieu PELLEN Theoretical calculations for phenomenology at the LHC 14 / 22
NLO QCD/EW corrections in POWHEG
2) Same-sign W-boson scattering at NLO EW[Chiesa, Denner, Lang, MP; 1906.01863]
Interface with general matrix-element generator:Recola [Actis, Denner, Hofer, Lang, Scharf; 1605.01090]! Basis of general interface [Chiesa, Oleari, Re; 2005.12146]
O�↵s↵5�O�↵6� O�↵2s↵4
�LO
O�↵7� O�↵s↵6� O�↵2s↵5
� O�↵3s↵4�
NLO
EW
QCD
EW
QCD
EW
QCD
! To be used with other contributions available in POWHEG[Melia, Nason, Rontsch, Zanderighi; 1102.4846] [Jäger, Zanderighi; 1108.0864]
Mathieu PELLEN Theoretical calculations for phenomenology at the LHC 15 / 22
NNLO QCD corrections in StripperStripper:Implementation of sector-improved residue subtraction scheme
[Czakon, Heymes, Poncelet; 1005.0274, 1101.0642, 1408.2500]
! General framework for NNLO QCD computations! As POWHEG, implementation on a process-by-process basisMy work
Implementation of integration channel! mapping of resonanceInterface with OpenLoops2 [Buccioni, et al.; 1907.13071]
Implementation of two-loop virtual [Gehrmann, Tancredi; 1112.1531]! Convention matching with complex expressions! Evaluation of harmonic polylogarithms with ...... Ginac [Bauer, Frink, Kreckel], [Vollinga, Weinzierl; hep-ph/0410259]
! Outcome: NNLO QCD corrections for W+c-jet[Czakon, Mitov, MP, Poncelet; 2011.01011]
Mathieu PELLEN Theoretical calculations for phenomenology at the LHC 16 / 22
Automation of NLO QCD and EW in Sherpa
Sherpa: General multi-purpose Monte Carlo[Gleisberg, Höche, Krauss, Schönherr, Schälicke, Schumann, Siegert, Winter; hep-ph/0311263, 0811.4622]
[Biedermann, Bräuer, Denner, MP, Schumann, Thompson; 1704.05783]
General implementation of any NLO corrections! also mixed correctionsDesign of interface between Sherpa and Recola! C++ $ Fortran
Output
NLO corrections for any process
Use all functionalities of Sherpa along with NLO corrections
Applications:! t̄t, ZZ, V + jets [Biedermann, Bräuer, Denner, MP, Schumann, Thompson; 1704.05783]3-jets [Reyer, Schönherr, Schumann; 1902.01763], tri-bosons [Reyer, Schönherr, Schumann;1806.00307], WW/WWj [Bräuer, Denner, MP, Schönherr, Schumann; 2011.01011]
Mathieu PELLEN Theoretical calculations for phenomenology at the LHC 17 / 22
NLO QCD corrections in MadGraph5 aMC@NLO
! Automation NLO QCD for Dark-Matter simplified models[Backovic, Krämer, Maltoni, Martini, Mawatari, MP; 1508.05327]
Tool chain
FeynRules [Alloul et al.; 1310.1921]
NLOCT [Degrande; 1406.3030]
FeynArts [Hahn; hep-ph/0012260]
! NLO QCD UFO files [Degrande et al.; 1108.2040]: DMsimp
! Can be used for any process in MG5 aMC [Alwall et al.; 1405.0301]! Used extensively by both communities:
Experiment: for all Dark-Matter searches in ATLAS and CMS
Theory: [Haisch, Kahlhoefer, Tait; 1603.01267], [Asadi et al.; 1603.01267], ...
Mathieu PELLEN Theoretical calculations for phenomenology at the LHC 18 / 22
Development of MoCaNLO - past
MoCaNLO: Monte Carlo event generator for NLOcalculations of hadron-collider processes
! Multi-channel Monte Carlo written by Robert FegerMy work
Make it more general
NLO EW corrections! Treatment of mixed QCD-EW correctionsPole approximation at NLO QCD/EW! non-factorisable correctionsPerformance improvements
Further automation of the code
! E�cient for high-multiplicity processes (2 ! 6 and beyond)
Mathieu PELLEN Theoretical calculations for phenomenology at the LHC 19 / 22
Development of MoCaNLO - future
! Frontier of the code:pp ! µ�⌫̄µe+⌫eb̄bb̄b at NLO QCD(2 ! 8 scattering with ...... 6 external QCD particles)[Denner, Lang, MP; 2008.00918]
10�4
10�3
10�2
10�1
d�[fb]/
dm
b1b
2[G
eV]
LO
LODPA
NLO
NLODPA
8090
100110
NLO
k
LO
k�
1[%
] k = full k = DPA
0 200 400 600mb1b2 [GeV]
�10�5
05
kDPA
kfull
�1[
%]
k = LO k = NLO
Plan: Make it better and even more general
Implementation of FKS subtraction [Frixione, Kunszt, Signer; hep-ph/9512328]
Matching to parton shower! mixed QCD-EW correctionsUsable for new physics models
Making it public!
Mathieu PELLEN Theoretical calculations for phenomenology at the LHC 20 / 22
Partial summary
Focus
Implementation of higher-order corrections
Development of Monte Carlo programs
Skills
Knowledge of several programming languages
Experience in using HEP tools
Intensive use of High-performance computing
Experience in maintaining codes
! Research mainly focused on LHC physics but ...... tools can be used in other fields e.g. Astroparticle physics[Ali Cavasonza, Krämer, MP; 1409.8226], [Ali Cavasonza, Gast, Krämer, MP, Schael; 1612.06634]
... also interest in numerical general relativity[Di Menza, Nicolas, MP; 1903.02941]
Mathieu PELLEN Theoretical calculations for phenomenology at the LHC 21 / 22
Partial summary
Focus
Implementation of higher-order corrections
Development of Monte Carlo programs
Skills
Knowledge of several programming languages
Experience in using HEP tools
Intensive use of High-performance computing
Experience in maintaining codes
! Research mainly focused on LHC physics but ...... tools can be used in other fields e.g. Astroparticle physics[Ali Cavasonza, Krämer, MP; 1409.8226], [Ali Cavasonza, Gast, Krämer, MP, Schael; 1612.06634]
... also interest in numerical general relativity[Di Menza, Nicolas, MP; 1903.02941]
Mathieu PELLEN Theoretical calculations for phenomenology at the LHC 21 / 22
Partial summary
Focus
Implementation of higher-order corrections
Development of Monte Carlo programs
Skills
Knowledge of several programming languages
Experience in using HEP tools
Intensive use of High-performance computing
Experience in maintaining codes
! Research mainly focused on LHC physics but ...... tools can be used in other fields e.g. Astroparticle physics[Ali Cavasonza, Krämer, MP; 1409.8226], [Ali Cavasonza, Gast, Krämer, MP, Schael; 1612.06634]
... also interest in numerical general relativity[Di Menza, Nicolas, MP; 1903.02941]
Mathieu PELLEN Theoretical calculations for phenomenology at the LHC 21 / 22
General summary
Theoretical calculations for phenomenology at the LHC
Exploring the Electroweak sector of the Standard Model! several examples of recent computations
Development of methods and tools for LHC phenomenology! several examples of tools developed
Thank you
Mathieu PELLEN Theoretical calculations for phenomenology at the LHC 22 / 22
General summary
Theoretical calculations for phenomenology at the LHC
Exploring the Electroweak sector of the Standard Model! several examples of recent computations
Development of methods and tools for LHC phenomenology! several examples of tools developed
Thank you
Mathieu PELLEN Theoretical calculations for phenomenology at the LHC 22 / 22
Back-up slides
BACK-UP
Mathieu PELLEN Theoretical calculations for phenomenology at the LHC 23 / 22
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