280 research outputs found

    Disentangling Boosted Higgs Boson Production Modes with Machine Learning

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    Higgs Bosons produced via gluon-gluon fusion (ggF) with large transverse momentum (pTp_T) are sensitive probes of physics beyond the Standard Model. However, high pTp_T Higgs Boson production is contaminated by a diversity of production modes other than ggF: vector boson fusion, production of a Higgs boson in association with a vector boson, and production of a Higgs boson with a top-quark pair. Combining jet substructure and event information with modern machine learning, we demonstrate the ability to focus on particular production modes. These tools hold great discovery potential for boosted Higgs bosons produced via ggF and may also provide additional information about the Higgs Boson sector of the Standard Model in extreme phase space regions for other production modes as well.Comment: 17 pages, 9 figure

    Exploring the Universality of Hadronic Jet Classification

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    The modeling of jet substructure significantly differs between Parton Shower Monte Carlo (PSMC) programs. Despite this, we observe that machine learning classifiers trained on different PSMCs learn nearly the same function. This means that when these classifiers are applied to the same PSMC for testing, they result in nearly the same performance. This classifier universality indicates that a machine learning model trained on one simulation and tested on another simulation (or data) will likely be optimal. Our observations are based on detailed studies of shallow and deep neural networks applied to simulated Lorentz boosted Higgs jet tagging at the LHC.Comment: 25 pages, 7 figures, 7 table

    Sensitivity Reach on the Heavy Neutral Leptons and τ\tau-Neutrino Mixing ∣UτN∣2|U_{\tau N}|^2 at the HL-LHC

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    The model of heavy neutral leptons (HNLs) is one of the well-motivated models beyond the standard model (BSM) from both theoretical and phenomenological point of views. It is an indispensable ingredient to explain the puzzle of tiny neutrino masses and the origin of the matter-antimatter asymmetry in our Universe, based on the models in which the simplest Type-I seesaw mechanism can be embedded. The HNL with a mass up to the electroweak scale is an attractive scenario which can be readily tested in present or near-future experiments including the LHC. In this work, we study the decay rates of HNLs and find the sensitive parameter space of the mixing angles between the active neutrinos and HNLs. Since the mixing between ντ \nu_{\tau} and HNL is not well established in literature compared with those of νe\nu_e and νμ\nu_{\mu} for the HNL of mass in the electroweak scale, we focus on the channel pp→W±(∗)+X→τ±N+X pp\rightarrow W^{\pm(\ast)} + X\rightarrow \tau^{\pm} N + X to search for HNLs at the LHC 14 TeV. The targeted signature consists of three prompt charged leptons, which include at least two tau leptons. After the signal-background analysis, we further set sensitivity bounds on the mixing ∣UτN∣2 |U_{\tau N}|^2 with MN M_N at High-Luminosity LHC (HL-LHC). We predict the testable bounds from HL-LHC can be stronger than the previous LEP constraints and Electroweak Precision Data (EWPD), especially for MN≲ M_N \lesssim 50 GeV can reach down to ∣UτN∣2≈2×10−6 |U_{\tau N}|^2 \approx 2\times 10^{-6} .Comment: Published versio
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