545 research outputs found

    Charged Higgs production from polarized top-quark decay in the 2HDM considering the general-mass variable-flavor-number scheme

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    Charged Higgs bosons H±H^\pm are predicted by some non-minimal Higgs scenarios, such as models containing Higgs triplets and two-Higgs-doublet models, so that the experimental observation of these bosons would indicate physics beyond the Standard Model. In the present work, we introduce a new channel to indirect search for the charged Higgses through the hadronic decay of polarized top quarks where a top quark decays into a charged Higgs H+H^+ and a bottom-flavored hadron BB via the hadronization process of the produced bottom quark, t()H++b(B+jet)t(\uparrow)\rightarrow H^++b(\to B+jet). To obtain the energy spectrum of produced BB-hadrons we present, for the first time, an analytical expression for the O(αs){\cal O}(\alpha_s) corrections to the differential decay width of the process tH+bt\rightarrow H^+b in the presence of a massive b-quark in the General-Mass Variable-Flavor-Number Scheme (GM-VFNS). We find that the most reliable predictions for the B-hadron energy spectrum are made in the GM-VFN scheme, specifically, when the Type-II 2HDM scenario is concerned

    Next-to-leading order corrections to the spin-dependent energy spectrum of hadrons from polarized top quark decay in the general two Higgs doublet model

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    In recent years, searches for the light and heavy charged Higgs bosons have been done by the ATLAS and the CMS collaborations at the Large Hadron Collider (LHC) in proton-proton collision. Nevertheless, a definitive search is a program that still has to be carried out at the LHC. The experimental observation of charged Higgs bosons would indicate physics beyond the Standard Model. In the present work, we study the scaled-energy distribution of bottom-flavored mesons (BB) inclusively produced in polarized top quark decays into a light charged Higgs boson and a massless bottom quark at next-to-leading order in the two-Higgs-doublet model; t()bH+BH++Xt(\uparrow)\to bH^+\to BH^++X. This spin-dependent energy distribution is studied in a specific helicity coordinate system where the polarization vector of the top quark is measured with respect to the direction of the Higgs momentum. The study of these energy distributions could be considered as a new channel to search for the charged Higgs bosons at the LHC. For our numerical analysis and phenomenological predictions, we restrict ourselves to the unexcluded regions of the MSSM mH+tanβm_{H^+}-\tan\beta parameter space determined by the recent results of the CMS \cite{CMS:2014cdp} and ATLAS \cite{TheATLAScollaboration:2013wia} collaborations.Comment: 10 pages, 6 figures. arXiv admin note: text overlap with arXiv:1611.0801

    Dynamical Systems on Hilbert C*-Modules

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    We investigate the generalized derivations and show that every generalized derivation on a simple Hilbert CC^*-module either is closable or has a dense range. We also describe dynamical systems on a full Hilbert CC^*-module M{\mathcal M} over a CC^*-algebra A{\mathcal A} as a one-parameter group of unitaries on M{\mathcal M} and prove that if α:RU(M)\alpha: \R\to U({\mathcal M}) is a dynamical system, where U(M)U({\mathcal M}) denotes the set of all unitary operator on M{\mathcal M}, then we can correspond a CC^*-dynamical system α\alpha^{'} on A{\mathcal A} such that if δ\delta and dd are the infinitesimal generators of α\alpha and α\alpha^{'} respectively, then δ\delta is a dd-derivation.Comment: 7 pages, minor changes, to appear in Bull. Iranian Math. So

    Indirect search for light charged Higgs bosons through the dominant semileptonic decays of top quark tb(B/D+X)+H+(τ+ντ)t\to b(\to B/D+X)+H^+(\to \tau^+\nu_\tau)

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    In this work we introduce a new channel to indirect search for the light charged Higgs bosons, which are predicted in several extensions of the standard model (SM) such as the two-Higgs-doublet models (2HDMs). We calculate the O(αs){\cal O}(\alpha_s) QCD radiative corrections to the energy distribution of bottom- and charmed-flavored hadrons (B/DB/D) produced in the dominant decays of the polarized top quark in the 2HDM, i.e. t()b(B/D+jet)+H+(τ+ντ)t(\uparrow)\longrightarrow b(\to B/D+\text{jet})+H^+(\to \tau^+\nu_\tau). %This analysis is studied in a specific helicity coordinate system where the polarization vector of the top quark is evaluated with respect to the momentum direction of the bottom quark. Generally, the energy distribution of hadrons is governed by the unpolarized rate and the polar and the azimuthal correlation functions which are related to the density matrix elements of the decay t()bH+t(\uparrow)\rightarrow bH^+. In our proposed channel, any deviation of the B/DB/D-meson energy spectrum from its corresponding SM predictions can be considered as a signal for the existence of charged Higgs at the LHC. We also calculate, for the first time, the azimuthal correlation rate Γϕ\Gamma_\phi at next-to-leading order which vanishes at the Born level.Comment: 10 pages, 5 figures, published in NPB 932 (2018) 50

    Measuring Perceived Trust in XAI-Assisted Decision-Making by Eliciting a Mental Model

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    This empirical study proposes a novel methodology to measure users' perceived trust in an Explainable Artificial Intelligence (XAI) model. To do so, users' mental models are elicited using Fuzzy Cognitive Maps (FCMs). First, we exploit an interpretable Machine Learning (ML) model to classify suspected COVID-19 patients into positive or negative cases. Then, Medical Experts' (MEs) conduct a diagnostic decision-making task based on their knowledge and then prediction and interpretations provided by the XAI model. In order to evaluate the impact of interpretations on perceived trust, explanation satisfaction attributes are rated by MEs through a survey. Then, they are considered as FCM's concepts to determine their influences on each other and, ultimately, on the perceived trust. Moreover, to consider MEs' mental subjectivity, fuzzy linguistic variables are used to determine the strength of influences. After reaching the steady state of FCMs, a quantified value is obtained to measure the perceived trust of each ME. The results show that the quantified values can determine whether MEs trust or distrust the XAI model. We analyze this behavior by comparing the quantified values with MEs' performance in completing diagnostic tasks.Comment: Accepted in IJCAI 2023 Workshop on Explainable Artificial Intelligence (XAI

    Measuring Perceived Trust in XAI-Assisted Decision-Making by Eliciting a Mental Model

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    This empirical study proposes a novel methodology to measure users' perceived trust in an Explainable Artificial Intelligence (XAI) model. To do so, users' mental models are elicited using Fuzzy Cognitive Maps (FCMs). First, we exploit an interpretable Machine Learning (ML) model to classify suspected COVID-19 patients into positive or negative cases. Then, Medical Experts' (MEs) conduct a diagnostic decision-making task based on their knowledge and then prediction and interpretations provided by the XAI model. In order to evaluate the impact of interpretations on perceived trust, explanation satisfaction attributes are rated by MEs through a survey. Then, they are considered as FCM's concepts to determine their influences on each other and, ultimately, on the perceived trust. Moreover, to consider MEs' mental subjectivity, fuzzy linguistic variables are used to determine the strength of influences. After reaching the steady state of FCMs, a quantified value is obtained to measure the perceived trust of each ME. The results show that the quantified values can determine whether MEs trust or distrust the XAI model. We analyze this behavior by comparing the quantified values with MEs' performance in completing diagnostic tasks

    Measuring Perceived Trust in XAI-Assisted Decision-Making by Eliciting a Mental Model

    Get PDF
    This empirical study proposes a novel methodology to measure users’ perceived trust in an Explainable Artificial Intelligence (XAI) model. To do so, users’ mental models are elicited using Fuzzy Cognitive Maps (FCMs). First, we exploit an interpretable Machine Learning (ML) model to classify suspected COVID-19 patients into positive or negative cases. Then, Medical Experts (MEs) conduct a diagnostic decision-making task based on their knowledge and the predictions and interpretations provided by the XAI model. In order to evaluate the impact of interpretations on perceived trust, explanation satisfaction attributes are rated by MEs through a survey. Then, they are considered as FCM’s concepts to determine their influences on each other and, ultimately, on the perceived trust. Moreover, to consider MEs’ mental subjectivity, fuzzy linguistic variables are used to determine the strength of influences. After reaching the steady state of FCMs, a quantified value is obtained to measure the perceived trust of each ME. The results show that the quantified values can determine whether MEs trust or distrust the XAI model. We analyze this behavior by comparing the quantified values with MEs’ performance in completing diagnostic tasks
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