cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.17182/hepdata.138985.v1/t23
title: "Corr. coeff. - third vs fourth $q^2$ moment - electron" of "Measurements of $q^2$ Moments of Inclusive $B \rightarrow X_c \ell^+ \nu_{\ell}$ Decays with Hadronic Tagging"

description: Correlation coefficients for the different lower thresholds between the third and the fourth $q^2$ moment in the electron channel with lower $q^2$ thresholds ranging from $3.0$ GeV$^2$ to $10.0$ GeV$^2$ in steps of $0.5$ GeV$^2$.
description: No data abstract available.
DOI: 10.17182/hepdata.138985.v1/t22
title: "Corr. coeff. - third vs third $q^2$ moment - electron" of "Measurements of $q^2$ Moments of Inclusive $B \rightarrow X_c \ell^+ \nu_{\ell}$ Decays with Hadronic Tagging"

description: Correlation coefficients for the different lower thresholds between the third and the third $q^2$ moment in the electron channel with lower $q^2$ thresholds ranging from $3.0$ GeV$^2$ to $10.0$ GeV$^2$ in steps of $0.5$ GeV$^2$.
description: No data abstract available.
DOI: 10.17182/hepdata.138985.v1/t24
title: "Corr. coeff. - fourth vs fourth $q^2$ moment - electron" of "Measurements of $q^2$ Moments of Inclusive $B \rightarrow X_c \ell^+ \nu_{\ell}$ Decays with Hadronic Tagging"

description: Correlation coefficients for the different lower thresholds between the fourth and the fourth $q^2$ moment in the electron channel with lower $q^2$ thresholds ranging from $3.0$ GeV$^2$ to $10.0$ GeV$^2$ in steps of $0.5$ GeV$^2$.
description: No data abstract available.
DOI: 10.17182/hepdata.138985.v1/t25
title: "Corr. coeff. - first vs first $q^2$ moment - muon" of "Measurements of $q^2$ Moments of Inclusive $B \rightarrow X_c \ell^+ \nu_{\ell}$ Decays with Hadronic Tagging"

description: Correlation coefficients for the different lower thresholds between the first and the first $q^2$ moment in the muon channel with lower $q^2$ thresholds ranging from $3.0$ GeV$^2$ to $10.0$ GeV$^2$ in steps of $0.5$ GeV$^2$.
description: No data abstract available.
DOI: 10.17182/hepdata.138985.v1/t26
title: "Corr. coeff. - first vs second $q^2$ moment - muon" of "Measurements of $q^2$ Moments of Inclusive $B \rightarrow X_c \ell^+ \nu_{\ell}$ Decays with Hadronic Tagging"

description: Correlation coefficients for the different lower thresholds between the first and the second $q^2$ moment in the muon channel with lower $q^2$ thresholds ranging from $3.0$ GeV$^2$ to $10.0$ GeV$^2$ in steps of $0.5$ GeV$^2$.
description: No data abstract available.
DOI: 10.17182/hepdata.138985.v1/t27
title: "Corr. coeff. - first vs third $q^2$ moment - muon" of "Measurements of $q^2$ Moments of Inclusive $B \rightarrow X_c \ell^+ \nu_{\ell}$ Decays with Hadronic Tagging"

description: Correlation coefficients for the different lower thresholds between the first and the third $q^2$ moment in the muon channel with lower $q^2$ thresholds ranging from $3.0$ GeV$^2$ to $10.0$ GeV$^2$ in steps of $0.5$ GeV$^2$.
description: No data abstract available.
DOI: 10.17182/hepdata.138985.v1/t28
title: "Corr. coeff. - first vs fourth $q^2$ moment - muon" of "Measurements of $q^2$ Moments of Inclusive $B \rightarrow X_c \ell^+ \nu_{\ell}$ Decays with Hadronic Tagging"

description: Correlation coefficients for the different lower thresholds between the first and the fourth $q^2$ moment in the muon channel with lower $q^2$ thresholds ranging from $3.0$ GeV$^2$ to $10.0$ GeV$^2$ in steps of $0.5$ GeV$^2$.
description: No data abstract available.
DOI: 10.17182/hepdata.138985.v1/t29
title: "Corr. coeff. - second vs second $q^2$ moment - muon" of "Measurements of $q^2$ Moments of Inclusive $B \rightarrow X_c \ell^+ \nu_{\ell}$ Decays with Hadronic Tagging"

description: Correlation coefficients for the different lower thresholds between the second and the second $q^2$ moment in the muon channel with lower $q^2$ thresholds ranging from $3.0$ GeV$^2$ to $10.0$ GeV$^2$ in steps of $0.5$ GeV$^2$.
description: No data abstract available.
DOI: 10.17182/hepdata.138985.v1/t30
title: "Corr. coeff. - second vs third $q^2$ moment - muon" of "Measurements of $q^2$ Moments of Inclusive $B \rightarrow X_c \ell^+ \nu_{\ell}$ Decays with Hadronic Tagging"

description: Correlation coefficients for the different lower thresholds between the second and the third $q^2$ moment in the muon channel with lower $q^2$ thresholds ranging from $3.0$ GeV$^2$ to $10.0$ GeV$^2$ in steps of $0.5$ GeV$^2$.
description: No data abstract available.
DOI: 10.17182/hepdata.138985.v1/t31
title: "Corr. coeff. - second vs fourth $q^2$ moment - muon" of "Measurements of $q^2$ Moments of Inclusive $B \rightarrow X_c \ell^+ \nu_{\ell}$ Decays with Hadronic Tagging"

description: Correlation coefficients for the different lower thresholds between the second and the fourth $q^2$ moment in the muon channel with lower $q^2$ thresholds ranging from $3.0$ GeV$^2$ to $10.0$ GeV$^2$ in steps of $0.5$ GeV$^2$.
description: No data abstract available.
DOI: 10.17182/hepdata.138985.v1/t32
title: "Corr. coeff. - third vs third $q^2$ moment - muon" of "Measurements of $q^2$ Moments of Inclusive $B \rightarrow X_c \ell^+ \nu_{\ell}$ Decays with Hadronic Tagging"

description: Correlation coefficients for the different lower thresholds between the third and the third $q^2$ moment in the muon channel with lower $q^2$ thresholds ranging from $3.0$ GeV$^2$ to $10.0$ GeV$^2$ in steps of $0.5$ GeV$^2$.
description: No data abstract available.
DOI: 10.17182/hepdata.138985.v1/t33
title: "Corr. coeff. - third vs fourth $q^2$ moment - muon" of "Measurements of $q^2$ Moments of Inclusive $B \rightarrow X_c \ell^+ \nu_{\ell}$ Decays with Hadronic Tagging"

description: Correlation coefficients for the different lower thresholds between the third and the fourth $q^2$ moment in the muon channel with lower $q^2$ thresholds ranging from $3.0$ GeV$^2$ to $10.0$ GeV$^2$ in steps of $0.5$ GeV$^2$.
description: No data abstract available.
DOI: 10.17182/hepdata.138985.v1/t34
title: "Corr. coeff. - fourth vs fourth $q^2$ moment - muon" of "Measurements of $q^2$ Moments of Inclusive $B \rightarrow X_c \ell^+ \nu_{\ell}$ Decays with Hadronic Tagging"

description: Correlation coefficients for the different lower thresholds between the fourth and the fourth $q^2$ moment in the muon channel with lower $q^2$ thresholds ranging from $3.0$ GeV$^2$ to $10.0$ GeV$^2$ in steps of $0.5$ GeV$^2$.
description: No data abstract available.
DOI: 10.17182/hepdata.138985.v1/t35
title: "Corr. coeff. - first vs second central $q^2$ moment - electron" of "Measurements of $q^2$ Moments of Inclusive $B \rightarrow X_c \ell^+ \nu_{\ell}$ Decays with Hadronic Tagging"

description: Correlation coefficients for the different lower thresholds between the first and the second central central $q^2$ moment in the electron channel with lower $q^2$ thresholds ranging from $3.0$ GeV$^2$ to $10.0$ GeV$^2$ in steps of $0.5$ GeV$^2$.
description: No data abstract available.
DOI: 10.17182/hepdata.138985.v1/t36
title: "Corr. coeff. - first vs third central $q^2$ moment - electron" of "Measurements of $q^2$ Moments of Inclusive $B \rightarrow X_c \ell^+ \nu_{\ell}$ Decays with Hadronic Tagging"

description: Correlation coefficients for the different lower thresholds between the first and the third central $q^2$ moment in the electron channel with lower $q^2$ thresholds ranging from $3.0$ GeV$^2$ to $10.0$ GeV$^2$ in steps of $0.5$ GeV$^2$.
description: No data abstract available.
DOI: 10.17182/hepdata.138985.v1/t37
title: "Corr. coeff. - first vs fourth central $q^2$ moment - electron" of "Measurements of $q^2$ Moments of Inclusive $B \rightarrow X_c \ell^+ \nu_{\ell}$ Decays with Hadronic Tagging"

description: Correlation coefficients for the different lower thresholds between the first and the fourth central $q^2$ moment in the electron channel with lower $q^2$ thresholds ranging from $3.0$ GeV$^2$ to $10.0$ GeV$^2$ in steps of $0.5$ GeV$^2$.
description: No data abstract available.
DOI: 10.17182/hepdata.138985.v1/t38
title: "Corr. coeff. - second vs second central $q^2$ moment - electron" of "Measurements of $q^2$ Moments of Inclusive $B \rightarrow X_c \ell^+ \nu_{\ell}$ Decays with Hadronic Tagging"

description: Correlation coefficients for the different lower thresholds between the second and the second central $q^2$ moment in the electron channel with lower $q^2$ thresholds ranging from $3.0$ GeV$^2$ to $10.0$ GeV$^2$ in steps of $0.5$ GeV$^2$.
description: No data abstract available.
DOI: 10.17182/hepdata.138985.v1/t39
title: "Corr. coeff. - second vs third central $q^2$ moment - electron" of "Measurements of $q^2$ Moments of Inclusive $B \rightarrow X_c \ell^+ \nu_{\ell}$ Decays with Hadronic Tagging"

description: Correlation coefficients for the different lower thresholds between the second and the third central $q^2$ moment in the electron channel with lower $q^2$ thresholds ranging from $3.0$ GeV$^2$ to $10.0$ GeV$^2$ in steps of $0.5$ GeV$^2$.
description: No data abstract available.
DOI: 10.17182/hepdata.138985.v1/t40
title: "Corr. coeff. - second vs fourth central $q^2$ moment - electron" of "Measurements of $q^2$ Moments of Inclusive $B \rightarrow X_c \ell^+ \nu_{\ell}$ Decays with Hadronic Tagging"

description: Correlation coefficients for the different lower thresholds between the second and the fourth central $q^2$ moment in the electron channel with lower $q^2$ thresholds ranging from $3.0$ GeV$^2$ to $10.0$ GeV$^2$ in steps of $0.5$ GeV$^2$.
description: No data abstract available.
DOI: 10.17182/hepdata.138985.v1/t41
title: "Corr. coeff. - third vs third central $q^2$ moment - electron" of "Measurements of $q^2$ Moments of Inclusive $B \rightarrow X_c \ell^+ \nu_{\ell}$ Decays with Hadronic Tagging"

description: Correlation coefficients for the different lower thresholds between the third and the third central $q^2$ moment in the electron channel with lower $q^2$ thresholds ranging from $3.0$ GeV$^2$ to $10.0$ GeV$^2$ in steps of $0.5$ GeV$^2$.
description: No data abstract available.
DOI: 10.17182/hepdata.138985.v1/t42
title: "Corr. coeff. - third vs fourth central $q^2$ moment - electron" of "Measurements of $q^2$ Moments of Inclusive $B \rightarrow X_c \ell^+ \nu_{\ell}$ Decays with Hadronic Tagging"

description: Correlation coefficients for the different lower thresholds between the third and the fourth central $q^2$ moment in the electron channel with lower $q^2$ thresholds ranging from $3.0$ GeV$^2$ to $10.0$ GeV$^2$ in steps of $0.5$ GeV$^2$.
description: No data abstract available.
DOI: 10.17182/hepdata.138985.v1/t43
title: "Corr. coeff. - fourth vs fourth central $q^2$ moment - electron" of "Measurements of $q^2$ Moments of Inclusive $B \rightarrow X_c \ell^+ \nu_{\ell}$ Decays with Hadronic Tagging"

description: Correlation coefficients for the different lower thresholds between the fourth and the fourth central $q^2$ moment in the electron channel with lower $q^2$ thresholds ranging from $3.0$ GeV$^2$ to $10.0$ GeV$^2$ in steps of $0.5$ GeV$^2$.
description: No data abstract available.
DOI: 10.17182/hepdata.138985.v1/t44
title: "Corr. coeff. - first vs second central $q^2$ moment - muon" of "Measurements of $q^2$ Moments of Inclusive $B \rightarrow X_c \ell^+ \nu_{\ell}$ Decays with Hadronic Tagging"

description: Correlation coefficients for the different lower thresholds between the first and the second central central $q^2$ moment in the muon channel with lower $q^2$ thresholds ranging from $3.0$ GeV$^2$ to $10.0$ GeV$^2$ in steps of $0.5$ GeV$^2$.
description: No data abstract available.
DOI: 10.17182/hepdata.138985.v1/t45
title: "Corr. coeff. - first vs third central $q^2$ moment - muon" of "Measurements of $q^2$ Moments of Inclusive $B \rightarrow X_c \ell^+ \nu_{\ell}$ Decays with Hadronic Tagging"

description: Correlation coefficients for the different lower thresholds between the first and the third central $q^2$ moment in the muon channel with lower $q^2$ thresholds ranging from $3.0$ GeV$^2$ to $10.0$ GeV$^2$ in steps of $0.5$ GeV$^2$.
description: No data abstract available.
DOI: 10.17182/hepdata.138985.v1/t46
title: "Corr. coeff. - first vs fourth central $q^2$ moment - muon" of "Measurements of $q^2$ Moments of Inclusive $B \rightarrow X_c \ell^+ \nu_{\ell}$ Decays with Hadronic Tagging"

description: Correlation coefficients for the different lower thresholds between the first and the fourth central $q^2$ moment in the muon channel with lower $q^2$ thresholds ranging from $3.0$ GeV$^2$ to $10.0$ GeV$^2$ in steps of $0.5$ GeV$^2$.
description: No data abstract available.
DOI: 10.17182/hepdata.138985.v1/t47
title: "Corr. coeff. - second vs second central $q^2$ moment - muon" of "Measurements of $q^2$ Moments of Inclusive $B \rightarrow X_c \ell^+ \nu_{\ell}$ Decays with Hadronic Tagging"

description: Correlation coefficients for the different lower thresholds between the second and the second central $q^2$ moment in the muon channel with lower $q^2$ thresholds ranging from $3.0$ GeV$^2$ to $10.0$ GeV$^2$ in steps of $0.5$ GeV$^2$.
description: No data abstract available.
DOI: 10.17182/hepdata.138985.v1/t48
title: "Corr. coeff. - second vs third central $q^2$ moment - muon" of "Measurements of $q^2$ Moments of Inclusive $B \rightarrow X_c \ell^+ \nu_{\ell}$ Decays with Hadronic Tagging"

description: Correlation coefficients for the different lower thresholds between the second and the third central $q^2$ moment in the muon channel with lower $q^2$ thresholds ranging from $3.0$ GeV$^2$ to $10.0$ GeV$^2$ in steps of $0.5$ GeV$^2$.
description: No data abstract available.
DOI: 10.17182/hepdata.138985.v1/t49
title: "Corr. coeff. - second vs fourth central $q^2$ moment - muon" of "Measurements of $q^2$ Moments of Inclusive $B \rightarrow X_c \ell^+ \nu_{\ell}$ Decays with Hadronic Tagging"

description: Correlation coefficients for the different lower thresholds between the second and the fourth central $q^2$ moment in the muon channel with lower $q^2$ thresholds ranging from $3.0$ GeV$^2$ to $10.0$ GeV$^2$ in steps of $0.5$ GeV$^2$.
description: No data abstract available.
DOI: 10.17182/hepdata.138985.v1/t50
title: "Corr. coeff. - third vs third central $q^2$ moment - muon" of "Measurements of $q^2$ Moments of Inclusive $B \rightarrow X_c \ell^+ \nu_{\ell}$ Decays with Hadronic Tagging"

description: Correlation coefficients for the different lower thresholds between the third and the third central $q^2$ moment in the muon channel with lower $q^2$ thresholds ranging from $3.0$ GeV$^2$ to $10.0$ GeV$^2$ in steps of $0.5$ GeV$^2$.
description: No data abstract available.
DOI: 10.17182/hepdata.138985.v1/t51
title: "Corr. coeff. - third vs fourth central $q^2$ moment - muon" of "Measurements of $q^2$ Moments of Inclusive $B \rightarrow X_c \ell^+ \nu_{\ell}$ Decays with Hadronic Tagging"

description: Correlation coefficients for the different lower thresholds between the third and the fourth central $q^2$ moment in the muon channel with lower $q^2$ thresholds ranging from $3.0$ GeV$^2$ to $10.0$ GeV$^2$ in steps of $0.5$ GeV$^2$.
description: No data abstract available.
DOI: 10.17182/hepdata.138985.v1/t52
title: "Corr. coeff. - fourth vs fourth central $q^2$ moment - muon" of "Measurements of $q^2$ Moments of Inclusive $B \rightarrow X_c \ell^+ \nu_{\ell}$ Decays with Hadronic Tagging"

description: Correlation coefficients for the different lower thresholds between the fourth and the fourth central $q^2$ moment in the muon channel with lower $q^2$ thresholds ranging from $3.0$ GeV$^2$ to $10.0$ GeV$^2$ in steps of $0.5$ GeV$^2$.
description: No data abstract available.
DOI: 10.17182/hepdata.138987.v1/t1
title: "Table 1" of "Search for doubly charged Higgs boson production in multi-lepton final states using 139 fb$^{-1}$ of proton-proton collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector"

description: LO, NLO cross-sections and K-factors for the pair-production of doubly charged Higgs bosons in pp collisions at $\sqrt{s}$ = 13 TeV. The K-factors (K=$\sigma_{NLO}/\sigma_{LO}$) are identical for $H^{\pm\pm}_L$, $H^{\pm\pm}_R$, and $k^{\pm\pm}$. The values are calculated using the NNPDF3.1NLO and NNPDF2.3LO PDF sets.
description: No data abstract available.
DOI: 10.17182/hepdata.138987.v1/t2
title: "Table 2" of "Search for doubly charged Higgs boson production in multi-lepton final states using 139 fb$^{-1}$ of proton-proton collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector"

description: Observed (solid line) and expected (dashed line) 95% CL upper limits on the $H^{\pm\pm}$ pair production cross-section as a function of $m(H^{\pm\pm})$ resulting from the combination of all analysis channels, assuming $\sum_{\ell \ell^\prime} \mathcal{B}(H^{\pm\pm} \rightarrow \ell^{\pm} \ell^{\prime \pm})=100%$, where $\ell, \ell^\prime = e, \mu, \tau$.
description: No data abstract available.
DOI: 10.17182/hepdata.138987.v1/t3
title: "Table 3" of "Search for doubly charged Higgs boson production in multi-lepton final states using 139 fb$^{-1}$ of proton-proton collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector"

description: Distribution of $m(e^{\pm},e^{\pm})_{\mathrm{lead}}$ in the electron-electron signal region after the background-only fit.
description: No data abstract available.
DOI: 10.17182/hepdata.138987.v1/t4
title: "Table 4" of "Search for doubly charged Higgs boson production in multi-lepton final states using 139 fb$^{-1}$ of proton-proton collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector"

description: Distribution of $m(e^{\pm},\mu^{\pm})_{\mathrm{lead}}$ in the electron-muon signal region after the background-only fit.
description: No data abstract available.
DOI: 10.17182/hepdata.138987.v1/t5
title: "Table 5" of "Search for doubly charged Higgs boson production in multi-lepton final states using 139 fb$^{-1}$ of proton-proton collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector"

description: Distribution of $m(\mu^{\pm},\mu^{\pm})_{\mathrm{lead}}$ in the muon-muon signal region after the background-only fit.
description: No data abstract available.
DOI: 10.17182/hepdata.138987.v1/t6
title: "Table 6" of "Search for doubly charged Higgs boson production in multi-lepton final states using 139 fb$^{-1}$ of proton-proton collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector"

description: Distribution of $m(\ell^{\pm},\ell^{\prime \pm})_{\mathrm{lead}}$ in the three-lepton signal region after the background-only fit.
description: No data abstract available.
DOI: 10.17182/hepdata.138987.v1/t7
title: "Table 7" of "Search for doubly charged Higgs boson production in multi-lepton final states using 139 fb$^{-1}$ of proton-proton collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector"

description: Event yield in the four-lepton signal region after the background-only fit.
description: No data abstract available.
DOI: 10.17182/hepdata.138987.v1/t8
title: "Table 8" of "Search for doubly charged Higgs boson production in multi-lepton final states using 139 fb$^{-1}$ of proton-proton collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector"

description: Two-lepton signal region weighted cutflows for electron-electron channel. Data and a few representative signal samples are presented alongside the main background contributions. Yield stands for the observed yield in data and the expected yields based on $\sigma \cdot \mathcal{L}$ for the signal and background samples. Top quark and multiboson process backgrounds are merged under the 'other' category.
description: No data abstract available.
DOI: 10.17182/hepdata.138987.v1/t9
title: "Table 9" of "Search for doubly charged Higgs boson production in multi-lepton final states using 139 fb$^{-1}$ of proton-proton collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector"

description: Two-lepton signal region weighted cutflows for electron-muon channel. Data and a few representative signal samples are presented alongside the main background contributions. Yield stands for the observed yield in data and the expected yields based on $\sigma \cdot \mathcal{L}$ for the signal and background samples. Top quark and multiboson process backgrounds are merged under the 'other' category.
description: No data abstract available.
DOI: 10.17182/hepdata.138987.v1/t10
title: "Table 10" of "Search for doubly charged Higgs boson production in multi-lepton final states using 139 fb$^{-1}$ of proton-proton collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector"

description: Two-lepton signal region weighted cutflows for muon-muon channel. Data and a few representative signal samples are presented alongside the main background contributions. Yield stands for the observed yield in data and the expected yields based on $\sigma \cdot \mathcal{L}$ for the signal and background samples. Top quark and multiboson process backgrounds are merged under the 'other' category.
description: No data abstract available.
DOI: 10.17182/hepdata.138987.v1/t11
title: "Table 11" of "Search for doubly charged Higgs boson production in multi-lepton final states using 139 fb$^{-1}$ of proton-proton collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector"

description: Three-lepton signal region weighted cutflow for $\ell \ell \ell$ channel. Data and a few representative signal samples are presented alongside the main background contributions. Yield stands for the observed yield in data and the expected yields based on $\sigma \cdot \mathcal{L}$ for the signal and background samples. Top quark and multiboson process backgrounds are merged under the 'other' category.
description: No data abstract available.
DOI: 10.17182/hepdata.138987.v1/t12
title: "Table 12" of "Search for doubly charged Higgs boson production in multi-lepton final states using 139 fb$^{-1}$ of proton-proton collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector"

description: Four-lepton signal region weighted cutflow for $\ell \ell \ell \ell$ channel. Data and a few representative signal samples are presented alongside the main background contributions. Yield stands for the observed yield in data and the expected yields based on $\sigma \cdot \mathcal{L}$ for the signal and background samples. Top quark, Drell-Yan, and multiboson process backgrounds are merged under the 'other' category.
description: No data abstract available.
DOI: 10.17182/hepdata.138996.v1/t1
title: "Table 1" of "Elliptic Flow of Heavy-Flavor Decay Electrons in Au+Au Collisions at $\sqrt{s_{_{\rm NN}}}$ = 27 and 54.4 GeV at RHIC"

description: Heavy-flavor decay electron $v_2$ as a function of electron $p_{\rm T}$ in Au+Au collisions at $\sqrt{s_{_{\rm NN}}}$ = 54.4 GeV.
description: We report on new measurements of elliptic flow ($v_2$) of electrons from heavy-flavor hadron decays at mid-rapidity ($|y|&lt;0.8$) in Au+Au collisions at $\sqrt{s_{_{\rm NN}}}$ = 27 and 54.4 GeV from the STAR experiment. Heavy-flavor decay electrons ($e^{\rm HF}$) in Au+Au collisions at $\sqrt{s_{_{\rm NN}}}$ = 54.4 GeV exhibit a non-zero $v_2$ in the transverse momentum ($p_{\rm T}$) region of $p_{\rm T}&lt;$ 2 GeV/$c$ with the magnitude comparable to that at $\sqrt{s_{\rm NN}}=200$ GeV. The measured $e^{\rm HF}$ $v_2$ at 54.4 GeV is also consistent with the expectation of their parent charm hadron $v_2$ following number-of-constituent-quark scaling as other light and strange flavor hadrons at this energy. These suggest that charm quarks gain significant collectivity through the evolution of the QCD medium and may reach local thermal equilibrium in Au+Au collisions at $\sqrt{s_{\rm NN}}=54.4$ GeV. The measured $e^{\rm HF}$ $v_2$ in Au+Au collisions at $\sqrt{s_{\rm NN}}=$ 27 GeV is consistent with zero within large uncertainties. The energy dependence of $v_2$ for different flavor particles ($\pi,\phi,D^{0}/e^{\rm HF}$) shows an indication of quark mass hierarchy in reaching thermalization in high-energy nuclear collisions.