NLO QCD+EW predictions for 2ℓ2ν diboson signatures at the LHC

2017/05/31 by S. Kallweit, J. M. Lindert, S. Pozzorini +2
Computer Science · Physics and Astronomy · #Computational Physics and Python Applications #Electroweak interaction #Large Hadron Collider #Lepton #Particle physics theoretical and experimental studies #Parton #Quantum Chromodynamics and Particle Interactions #Quantum chromodynamics #Resummation #hep-ex #hep-ph

paper · pdf · doi:10.1007/jhep11(2017)120

published as JHEP 1711 (2017) 120 · 25 pages + appendices, 22 figures

openalex created_date 2017/05/12 · openalex publication_date 2017/11/01 · arxiv created 2017/12/22 · arxiv updated 2017/12/25 · openalex updated_date 2026/08/06

Abstract

A bstract We present next-to-leading order (NLO) calculations including QCD and electroweak (EW) corrections for 2 ℓ 2 ν diboson signatures with two opposite-charge leptons and two neutrinos. Specifically, we study the processes pp→ e⁺μ^-ν_eν_μ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>pp</mml:mi><mml:mo>→</mml:mo><mml:msup><mml:mi>e</mml:mi><mml:mo>+</mml:mo></mml:msup><mml:msup><mml:mi>μ</mml:mi><mml:mo>−</mml:mo></mml:msup><mml:msub><mml:mi>ν</mml:mi><mml:mi>e</mml:mi></mml:msub><mml:msub><mml:mover><mml:mi>ν</mml:mi><mml:mo>¯</mml:mo></mml:mover><mml:mi>μ</mml:mi></mml:msub></mml:math> and pp→ e⁺e^-ν ν <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>pp</mml:mi><mml:mo>→</mml:mo><mml:msup><mml:mi>e</mml:mi><mml:mo>+</mml:mo></mml:msup><mml:msup><mml:mi>e</mml:mi><mml:mo>−</mml:mo></mml:msup><mml:mi>ν</mml:mi><mml:mover><mml:mi>ν</mml:mi><mml:mo>¯</mml:mo></mml:mover></mml:math> , including all relevant off-shell diboson channels, W + W − , ZZ , γ Z , as well as non-resonant contributions. Photon-induced processes are computed at NLO EW, and we discuss subtle differences related to the definition and the renormalisation of the coupling α for processes with initial- and final-state photons. All calculations are performed within the automated M unich /S herpa +O pen L oops frameworks, and we provide numerical predictions for the LHC at 13 TeV. The behaviour of the corrections is investigated with emphasis on the high-energy regime, where NLO EW effects can amount to tens of percent due to large Sudakov logarithms. The interplay between W W and ZZ contributions to the same-flavour channel, pp→ e⁺e^-ν ν <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>pp</mml:mi><mml:mo>→</mml:mo><mml:msup><mml:mi>e</mml:mi><mml:mo>+</mml:mo></mml:msup><mml:msup><mml:mi>e</mml:mi><mml:mo>−</mml:mo></mml:msup><mml:mi>ν</mml:mi><mml:mover><mml:mi>ν</mml:mi><mml:mo>¯</mml:mo></mml:mover></mml:math> , is discussed in detail, and a quantitative analysis of photon-induced contributions is presented. Finally, we consider approximations that account for all sources of large logarithms, at high and low energy, by combining virtual EW corrections with a YFS soft-photon resummation or a QED parton shower.

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