Identifying the Quantum Properties of Hadronic Resonances using Machine Learning

Filipek, Jakub; Hsu, Shih-Chieh; Kruper, John; Mohan, Kirtimaan; Nachman, Benjamin

doi:10.48550/arxiv.2105.04582

“…Fortunately, in the last years there has been tremendous progress on quark-gluon tagging studies exploiting jet substructure properties with machine learning techniques [42]. The latest LHC results reach ε g ≈ 60% gluon efficiencies with ε mistag q→g ≈ 10% false positive rates using advanced multivariate analyses [43,44], or ε mistag q→g ≈ 7% [45] further exploiting Lund jet plane information [46]. Reaching mistagging rates down to ε mistag q→g ≈ 1%, while keeping large gluon reconstruction efficiencies, appears feasible in the clean and kinematically constrained QCD environment of future e + e − machines, in particular taking advantage of the very large samples of Z → qq(g) events at the Z pole, and the O(10 5 ) H → gg events collected during the e + e − → ZH runs, available for dedicated studies of the different colour, radiation, spin, charge, hadronization properties of quark and gluon jets [47][48][49].…”

Section: Multivariate Analysis (Mva) Per Channelmentioning

confidence: 99%

Measuring the electron Yukawa coupling via resonant s-channel Higgs production at FCC-ee

d’Enterria

¹

,

Poldaru

²

,

Wojcik

³

2022

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The Future Circular Collider (FCC-ee) offers the unique opportunity of studying the Higgs Yukawa coupling to the electron, $$y_\mathrm {e}$$ y e , via resonant s-channel production, $$\mathrm {e^+e^-}\rightarrow \mathrm {H}$$ e + e - → H , in a dedicated run at $$\sqrt{s} = m_\mathrm {H}$$ s = m H . The signature for direct Higgs production is a small rise in the cross sections for particular final states, consistent with Higgs decays, over the expectations for their occurrence due to Standard Model (SM) background processes involving $$\mathrm {Z}^*$$ Z ∗ , $$\gamma ^*$$ γ ∗ , or t-channel exchanges alone. Performing such a measurement is remarkably challenging for four main reasons. First, the low value of the e$$^\pm $$ ± mass leads to a tiny $$y_\mathrm {e}$$ y e coupling and correspondingly small cross section: $$\sigma _\mathrm {ee\rightarrow H} \propto m_\mathrm {e}^2 = 0.57$$ σ ee → H ∝ m e 2 = 0.57 fb accounting for initial-state $$\gamma $$ γ radiation. Second, the $$\mathrm {e^+e^-}$$ e + e - beams must be monochromatized such that the spread of their centre-of-mass (c.m.) energy is commensurate with the narrow width of the SM Higgs boson, $$\varGamma _\mathrm {H} = 4.1$$ Γ H = 4.1 MeV, while keeping large beam luminosities. Third, the Higgs mass must also be known beforehand with a few-MeV accuracy in order to operate the collider at the resonance peak, $$\sqrt{s} = m_\mathrm {H}$$ s = m H . Last but not least, the cross sections of the background processes are many orders-of-magnitude larger than those of the Higgs decay signals. A preliminary generator-level study of 11 Higgs decay channels using a multivariate analysis, which exploits boosted decision trees to discriminate signal and background events, identifies two final states as the most promising ones in terms of statistical significance: $$\mathrm {H}\rightarrow gg$$ H → g g and $$\mathrm {H}\rightarrow \mathrm {W}\mathrm {W}^*\!\rightarrow \ell \nu $$ H → W W ∗ → ℓ ν + 2 jets. For a benchmark monochromatization with 4.1-MeV c.m. energy spread (leading to $$\sigma _\mathrm {ee\rightarrow H} = 0.28$$ σ ee → H = 0.28 fb) and 10 ab$$^{-1}$$ - 1 of integrated luminosity, a $$1.3\sigma $$ 1.3 σ signal significance can be reached, corresponding to an upper limit on the e$$^\pm $$ ± Yukawa coupling at 1.6 times the SM value: $$|y_\mathrm {e}|<1.6|y^\mathrm {\textsc {sm}}_\mathrm {e}|$$ | y e | < 1.6 | y e S M | at 95% confidence level, per FCC-ee interaction point per year. Directions for future improvements of the study are outlined.

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“…[5] analyzed the radiation patterns inside jets to separate singlet from octet color flows. Similar color flow ideas have been applied to distinguishing color octet and singlet dijet events [4] and top pair tagging [6] and many other new physics searches [7,[93][94][95]. This is also the basic idea of the rapidity gap [96].…”

Section: Jhep08(2023)173mentioning

confidence: 90%

A guide to diagnosing colored resonances at hadron colliders

Han,

Lewis,

Liu

et al. 2023

J. High Energ. Phys.

0

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We present a comprehensive study on how to distinguish the properties of heavy dijet resonances at hadron colliders. A variety of spins, chiral couplings, charges, and QCD color representations are considered. Distinguishing the different color representations is particularly difficult at hadron colliders. To determine the QCD color structure, we consider a third jet radiated in a resonant dijet event. We show that the relative rates of three-jet versus two-jet processes are sensitive to the color representation of the resonance. We also show analytically that the antennae radiation pattern of soft radiation depends on the color structure of dijet events and develops an observable that is sensitive to the antennae patterns. Finally, we exploit a Convolutional Neural Network with Machine Learning techniques to differentiate the radiation patterns from different colored resonances and find encouraging results to discriminate them. We demonstrate our results numerically at a 14 TeV LHC, and the methodology presented here should be applicable to other future hadron colliders.

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“…Fortunately, in the last years there has been tremendous progress on quark-gluon tagging studies exploiting jet substructure properties with machine learning techniques [41]. The latest LHC results reach ε g ≈ 60% gluon efficiencies with ε mistag q→g ≈ 10% false positive rates using advanced multivariate analyses [42,43], or ε mistag q→g ≈ 7% [44] further exploiting Lund jet plane information [45]. Reaching mistagging rates down to ε mistag q→g ≈ 1%, while keeping large gluon reconstruction efficiencies, appears feasible in the clean and kinematically constrained QCD environment of future e + e − machines, in particular taking advantage of the very large samples of Z → qq(g) events at the Z pole, and the O(10 5 ) H → gg events collected during the e + e − → ZH runs, available for dedicated studies of the different colour, radiation, spin, charge, hadronization properties of quark and gluon jets [46,47,48].…”

Section: Event Reconstruction and Preselectionmentioning

confidence: 99%

Measuring the electron Yukawa coupling via resonant s-channel Higgs production at FCC-ee

d'Enterria,

Poldaru,

Wojcik

2021

Preprint

View full text Add to dashboard Cite

The Future Circular Collider (FCC-ee) offers the unique opportunity of studying the Higgs Yukawa coupling to the electron, y e , via resonant s-channel production, e + e − → H, in a dedicated run at √ s = m H . The signature for direct Higgs production is a small rise in the cross sections for particular final states, consistent with Higgs decays, over the expectations for their occurrence due to Standard Model (SM) background processes involving Z * , γ * , or t-channel exchanges alone. Performing such a measurement is remarkably challenging for four main reasons. First, the low value of the e ± mass leads to a tiny y e coupling, and correspondingly small cross section: σ ee→H ∝ m 2 e = 0.57 fb accounting for initial-state γ radiation. Second, the e + e − beams must be monochromatized such that the spread of their center-ofmass (c.m.) energy is commensurate with the narrow width of the SM Higgs boson, Γ H = 4.1 MeV, while keeping large beam luminosities. Third, the Higgs mass must also be known beforehand with a few-MeV accuracy in order to operate the collider at the resonance peak, √ s = m H . Last but not least, the cross sections of the background processes are many orders-of-magnitude larger than those of the Higgs decay signals. A preliminary generator-level study of 11 Higgs decay channels using a multivariate analysis, which exploits boosted decision trees to discriminate signal and background events, identifies two final states as the most promising ones in terms of statistical significance: H → gg and H → WW * → ν + 2 jets. For a benchmark monochromatization with 4.1-MeV c.m. energy spread (leading to σ ee→H = 0.28 fb) and 10 ab −1 of integrated luminosity, a 1.3σ signal significance can be reached, corresponding to an upper limit on the e ± Yukawa coupling at 1.6 times the SM value: |y e | < 1.6|y sm e | at 95% confidence level, per FCC-ee interaction point per year. Directions for future improvements of the study are outlined.

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Identifying the Quantum Properties of Hadronic Resonances using Machine Learning

Cited by 4 publications

References 76 publications

Measuring the electron Yukawa coupling via resonant s-channel Higgs production at FCC-ee

Measuring the electron Yukawa coupling via resonant s-channel Higgs production at FCC-ee

A guide to diagnosing colored resonances at hadron colliders

Measuring the electron Yukawa coupling via resonant s-channel Higgs production at FCC-ee

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