PELLEN mpi Munich 2021 · 2021. 1. 25. · 2) pp ! W+W j @ NLO QCD+EW with parton shower q q¯ e W...

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Theoretical calculations for 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 26 th of January 2021
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Transcript of PELLEN mpi Munich 2021 · 2021. 1. 25. · 2) pp ! W+W j @ NLO QCD+EW with parton shower q q¯ e W...

  • 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

    g

    ⌫µ

    µ+

    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

    g

    ⌫µ

    µ+

    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

    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

    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

    [email protected] ! µ+nµe�n̄epp ! + 0,[email protected] + 2,[email protected]

    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

    [email protected]

    LOQ

    CD

    njet = 1

    She

    rpa

    +Re

    co

    la

    [email protected] pp ! µ+nµe�n̄e + 0,[email protected] + 2,[email protected]

    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

    [email protected]

    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

    [email protected] pp ! µ+nµe�n̄e + 0,[email protected] + 2,[email protected]

    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

    [email protected]

    NLO

    QC

    D

    She

    rpa

    +Re

    co

    la

    LONLO QCD

    NLO QCD + EWapproxNLO QCD ⇥ EWapprox

    [email protected] pp ! µ+nµe�n̄e + 0,[email protected] + 2,[email protected]

    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

    [email protected]

    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

    d

    ⌫ee+⌫µµ+

    W+

    W+

    W+

    W+

    u

    d

    ⌫ee+⌫µµ+W

    +

    W+

    u

    g

    d

    ⌫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

    d

    ⌫ee+⌫µµ+

    W+

    W+

    W+

    W+

    u

    d

    ⌫ee+⌫µµ+W

    +

    W+

    u

    g

    d

    ⌫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

    d

    ⌫ee+⌫µµ+

    W+

    W+

    W+

    W+

    u

    d

    ⌫ee+⌫µµ+W

    +

    W+

    u

    g

    d

    ⌫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 [email protected]

    ! 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