Exploiting the WH/ZH symmetry in the search for new physics.
TL;DR: It is suggested to isolate the loop-induced gluon-initiated component by using the similarity of the Drell–Yan-like component for associated ZH-ZH production to the WH process, and it is argued that the cross-section ratio of the latter two processes can be predicted with high theoretical accuracy.
Abstract: We suggest to isolate the loop-induced gluon-initiated component (
$$gg\rightarrow ZH$$
) for associated $$ZH$$
production by using the similarity of the Drell–Yan-like component for $$ZH$$
production to the $$WH$$
process. We argue that the cross-section ratio of the latter two processes can be predicted with high theoretical accuracy. Comparing it to the experimental $$ZH/WH$$
cross-section ratio should allow to probe for new physics in the $$gg\rightarrow ZH$$
component at the HL-LHC. We consider typical BSM scenarios in order to exemplify the effect they would have on the proposed observable.
Citations
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TL;DR: The precision frontier in collider physics is being pushed at impressive speed, from both the experimental and the theoretical side as discussed by the authors, and the aim of this review is to give an overview of recent developments in precision calculations within the Standard Model of particle physics, in particular in the Higgs sector.
140 citations
Cites methods from "Exploiting the WH/ZH symmetry in th..."
...[219], a data-driven strategy to extract the gluon-initiated component...
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Journal Article•
TL;DR: In this article, combined ATLAS and CMS measurements of the Higgs boson production and decay rates, as well as constraints on its couplings to vector bosons and fermions, are presented.
Abstract: Combined ATLAS and CMS measurements of the Higgs boson production and decay rates, as well as constraints on its couplings to vector bosons and fermions, are presented. The combination is based on the analysis of five production processes, namely gluon fusion, vector boson fusion, and associated production with a W or a Z boson or a pair of top quarks, and of the six decay modes H → ZZ,WW , γγ, ττ, bb, and μμ. All results are reported assuming a value of 125.09 GeV for the Higgs boson mass, the result of the combined measurement by the ATLAS and CMS experiments. The analysis uses the CERN LHC proton-proton collision data recorded by the ATLAS and CMS experiments in 2011 and 2012, corresponding to integrated luminosities per experiment of approximately 5 fb−1 at √ s = 7 TeV and 20 fb−1 at √ s = 8 TeV. The Higgs boson production and decay rates measured by the two experiments are combined within the context of three generic parameterisations: two based on cross sections and branching fractions, and one on ratios of coupling modifiers. Several interpretations of the measurements with more model-dependent parameterisations are also given. The combined signal yield relative to the Standard Model prediction is measured to be 1.09±0.11. The combined measurements lead to observed significances for the vector boson fusion production process and for the H → ττ decay of 5.4 and 5.5 standard deviations, respectively. The data are consistent with the Standard Model predictions for all parameterisations considered.
75 citations
TL;DR: In this article, the authors studied the process of reconstructing the Higgs boson at high energies using subjet techniques using the standard model effective field theory (SMEFT).
Abstract: We study the process pp → Zðlþl−Þhðbb¯Þ in the standard model effective field theory (SMEFT) at
high energies using subjet techniques to reconstruct the Higgs boson. We show that at high energies this
process probes four directions in the dimension-6 EFT space, namely the operators that contribute to the
four contact interactions, hZμf¯ γμf, where f ¼ uL; uR; dL and dR. These four directions are, however,
already constrained by the Z-pole and diboson measurements at LEP. We show that by utilizing the energy
growth of this process in the SMEFT and the accuracy that can be achieved by using subjet techniques at the
High Luminosity LHC, one can obtain bounds on these operators that are an order of magnitude better than
existing LEP bounds.
65 citations
TL;DR: In this paper, an extension of the JHUGen and MELA framework is presented, which includes an event generator and library for the matrix element analysis, enabling simulation, optimal discrimination, reweighting techniques, and analysis of a bosonic resonance and the triple and quartic gauge boson interactions with the most general anomalous couplings.
Abstract: We present an extension of the JHUGen and MELA framework, which includes an event generator and library for the matrix element analysis. It enables simulation, optimal discrimination, reweighting techniques, and analysis of a bosonic resonance and the triple and quartic gauge boson interactions with the most general anomalous couplings. The new features, which become especially relevant at the current stage of LHC data taking, are the simulation of gluon fusion and vector boson fusion in the off-shell region, associated $ZH$ production at NLO QCD including the $gg$ initial state, and the simulation of a second spin-zero resonance. We also quote translations of the anomalous coupling measurements into constraints on dimension-six operators of an effective field theory. Some of the new features are illustrated with projections for experimental measurements with the full LHC and HL-LHC datasets.
52 citations
Cites background from "Exploiting the WH/ZH symmetry in th..."
...This allows us to build on the previously studied topics [1–4, 10–58] and present phenomenological results in a unified approach....
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...[51] R....
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TL;DR: In this article, a next-to-next-toleading order (NNLO) accurate description of associated HZ production, followed by the Higgs boson decay into a pair of b-quarks treated at NLO, consistently matched to a parton shower (PS), is presented.
Abstract: We present a next-to-next-to-leading order (NNLO) accurate description of associated HZ production, followed by the Higgs boson decay into a pair of b-quarks treated at next-to-leading order (NLO), consistently matched to a parton shower (PS). The matching is achieved by performing reweighting of the HZJ-MiNLO events, using multi-dimensional distributions that are fully-differential in the HZ Born kinematics, to the NNLO results obtained by using the MCFM-8.0 fixed-order calculation. Additionally we include the gg → HZ contribution to the discussed process that appears at the $$ \mathcal{O}\left({\alpha}_s^2\right) $$
. We present phenomenological results obtained for 13 TeV hadronic collisions.
35 citations
References
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9,282 citations
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TL;DR: MadGraph5 aMC@NLO as discussed by the authors is a computer program capable of handling all these computations, including parton-level fixed order, shower-matched, merged, in a unified framework whose defining features are flexibility, high level of parallelisation and human intervention limited to input physics quantities.
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6,509 citations
"Exploiting the WH/ZH symmetry in th..." refers methods in this paper
...The uncertainties in this case have been calculated using MadGraph5 aMC@NLO [35, 36] MC@NLO events with one emission added through the HERWIG 7 parton shower [37,38]....
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TL;DR: FastJet as mentioned in this paper is a C++ package that provides a broad range of jet finding and analysis tools, including efficient native implementations of all widely used 2→1 sequential recombination jet algorithms for pp and e − − collisions.
Abstract: FastJet is a C++ package that provides a broad range of jet finding and analysis tools. It includes efficient native implementations of all widely used 2→1 sequential recombination jet algorithms for pp and e
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e
− collisions, as well as access to 3rd party jet algorithms through a plugin mechanism, including all currently used cone algorithms. FastJet also provides means to facilitate the manipulation of jet substructure, including some common boosted heavy-object taggers, as well as tools for estimation of pileup and underlying-event noise levels, determination of jet areas and subtraction or suppression of noise in jets.
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TL;DR: The ideas and the most important developments of the code are described and the capabilities of the MadGraph matrix element generator are illustrated through a few simple phenomenological examples.
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2,684 citations