Date

Observation of a Three-Resonance Structure in the Cross Section of $e^+e^-\to\pi^+\pi^- h_c$

The BESIII collaboration Ablikim, Medina ; Achasov, Mikhail N. ; Adlarson, Patrik Adlarsson ; et al.
2025.
Inspire Record 2908630 DOI 10.17182/hepdata.160247

Using $e^+e^-$ collision data collected with the BESIII detector operating at the Beijing Electron Positron Collider, the cross section of $e^+e^-\to \pi^+\pi^- h_c$ is measured at 59 points with center-of-mass energy $\sqrt{s}$ ranging from $4.009$ to $4.950~\mathrm{GeV}$ with a total integrated luminosity of $22.2~\mathrm{fb}^{-1}$. The cross section between $4.3$ and $4.45~\mathrm{GeV}$ exhibits a plateau-like shape and drops sharply around $4.5~\mathrm{GeV}$, which cannot be described by two resonances only. Three coherent Breit-Wigner functions are used to parameterize the $\sqrt{s}$-dependent cross section line shape. The masses and widths are determined to be $M_1=(4223.6_{-3.7-2.9}^{+3.6+2.6})~\mathrm{MeV}/c^2$, $\Gamma_1=(58.5_{-11.4-6.5}^{+10.8+6.7})~\mathrm{MeV}$, $M_2=(4327.4_{-18.8-9.3}^{+20.1+10.7})~\mathrm{MeV}/c^2$, $\Gamma_2=(244.1_{-27.1-18.0}^{+34.0+23.9})~\mathrm{MeV}$, and $M_3=(4467.4_{-5.4-2.7}^{+7.2+3.2})~\mathrm{MeV}/c^2$, $\Gamma_3=(62.8_{-14.4-6.6}^{+19.2+9.8})~\mathrm{MeV}$. The first uncertainties are statistical and the other two are systematic. The statistical significance of the three Breit-Wigner assumption over the two Breit-Wigner assumption is greater than $5\sigma$.

3 data tables

Dressed cross section at the 19 XYZ-I energy points with large statistics. The table also lists the integral luminosity, the number of signal events, the weighted efficiency, the radiative correction factor, and the dressed cross section. For the dressed cross section, the first error is statistical, the second error is the systematic, and the third error comes from the input branching ratios which is the dominant one in the multiplicative systematic uncertainties.

Dressed cross section at the 25 XYZ-II energy points with lower statistics. The table also lists the integral luminosity, the number of signal events, the weighted efficiency, the radiative correction factor, and the dressed cross section. For the dressed cross section, the first error is statistical, the second error is the systematic, and the third error comes from the input branching ratios which is the dominant one in the multiplicative systematic uncertainties.

Dressed cross section and its upper limit at the 15 R-scan energy points with small statistics. The table also lists the integral luminosity, the number of signal events, the weighted efficiency, the radiative correction factor, and the dressed cross section. For the dressed cross section, the first error is statistical, the second error is the systematic, and the third error comes from the input branching ratios which is the dominant one in the multiplicative systematic uncertainties.


Inclusive Search for Anomalous Single-Photon Production in MicroBooNE

The MicroBooNE collaboration Abratenko, P. ; Aldana, D. Andrade ; Arellano, L. ; et al.
FERMILAB-PUB-25-0055-PPD, 2025.
Inspire Record 2878293 DOI 10.17182/hepdata.158440

We present an inclusive search for anomalous production of single-photon events from neutrino interactions in the MicroBooNE experiment. The search and its signal definition are motivated by the previous observation of a low-energy excess of electromagnetic shower events from the MiniBooNE experiment. We use the Wire-Cell reconstruction framework to select a sample of inclusive single-photon final-state interactions with a final efficiency and purity of 7.0% and 40.2%, respectively. We leverage simultaneous measurements of sidebands of charged current $\nu_{\mu}$ interactions and neutral current interactions producing $\pi^{0}$ mesons to constrain signal and background predictions and reduce uncertainties. We perform a blind analysis using a dataset collected from February 2016 to July 2018, corresponding to an exposure of $6.34\times10^{20}$ protons on target from the Booster Neutrino Beam (BNB) at Fermilab. In the full signal region, we observe agreement between the data and the prediction, with a goodness-of-fit $p$-value of 0.11. We then isolate a sub-sample of these events containing no visible protons, and observe $93\pm22\text{(stat.)}\pm35\text{(syst.)}$ data events above prediction, corresponding to just above $2\sigma$ local significance, concentrated at shower energies below 600 MeV.

19 data tables

Fig. 2. The reconstructed shower energy. The individual signal and background event type categories added together form the unconstrained prediction.

Fig. 2. The constrained covariance matrix for the reconstructed shower energy. The matrix shows uncertainties and correlations between bins due to flux uncertainties, cross-section uncertainties, hadron reinteraction uncertainties, detector systematic uncertainties, Monte-Carlo statistical uncertainties, and dirt (outside cryostat) uncertainties. Data statistical uncertainties are not included. An example of how to add Pearson data statistical uncertainties can be found in the example code repository.

Fig. 2, Suppl. Fig. 5. The unconstrained covariance matrix for the reconstructed shower energy. The matrix shows uncertainties and correlations between bins due to flux uncertainties, cross-section uncertainties, hadron reinteraction uncertainties, detector systematic uncertainties, Monte-Carlo statistical uncertainties, and dirt (outside cryostat) uncertainties. Data statistical uncertainties are not included. An example of how to add Pearson data statistical uncertainties can be found in the example code repository.

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Enhanced Search for Neutral Current $\Delta$ Radiative Single-Photon Production in MicroBooNE

The MicroBooNE collaboration Abratenko, P. ; Aldana, D. Andrade ; Arellano, L. ; et al.
FERMILAB-PUB-25-0054-PPD, 2025.
Inspire Record 2878288 DOI 10.17182/hepdata.158441

We report results from an updated search for neutral current (NC) resonant $\Delta$(1232) baryon production and subsequent $\Delta$ radiative decay (NC $\Delta\rightarrow N \gamma$). We consider events with and without final state protons; events with a proton can be compared with the kinematics of a $\Delta(1232)$ baryon decay, while events without a visible proton represent a more generic phase space. In order to maximize sensitivity to each topology, we simultaneously make use of two different reconstruction paradigms, Pandora and Wire-Cell, which have complementary strengths, and select mostly orthogonal sets of events. Considering an overall scaling of the NC $\Delta\rightarrow N \gamma$ rate as an explanation of the MiniBooNE anomaly, our data exclude this hypothesis at 94.4% CL. When we decouple the expected correlations between NC $\Delta\rightarrow N \gamma$ events with and without final state protons, and allow independent scaling of both types of events, our data exclude explanations in which excess events have associated protons, and do not exclude explanations in which excess events have no associated protons.

15 data tables

The four bins correspond to WC $1\gamma Np$, WC $1\gamma 0p$, Pandora $1\gamma 1p$, and Pandora $1\gamma 0p$ predictions. Systematic uncertainties on the predictions are illustrated, and a more detailed covariance matrix is included in the Constrained Signal Channels Covariance Matrix and Signal And Constraining Channels Covariance Matrix tabs. This corresponds to Fig. 1 and Table III of the paper.

Covariance matrix showing constrained uncertainties and correlations between bins due to flux uncertainties, cross-section uncertainties, hadron reinteraction uncertainties, detector systematic uncertainties, Monte-Carlo statistical uncertainties, and dirt (outside cryostat) uncertainties. Pearson data statistical uncertainties have been included, and include small correlations due to events which can be selected by both WC and Pandora. The four bins are the WC $1\gamma Np$, WC $1\gamma 0p$, Pandora $1\gamma 1p$, and Pandora $1\gamma 0p$ channels. This corresponds to Fig. 1 and Table II of the paper.

Four constraining channels. The four channels in order are NC $\pi^0 Np$, NC $\pi^0 0p$, $\nu_\mu$CC $Np$, and $\nu_\mu$CC $0p$. Each channel contains 15 bins from 0 to 1500 MeV of reconstructed neutrino energy, with an additional overflow bin. Unconstrained and constrained systematic uncertainties on the predictions are illustrated, and a more detailed covariance matrix is included in the Signal And Constraining Channels Covariance Matrix tab. This corresponds to Fig. 6 of the Supplemental Material.

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Search for an Anomalous Production of Charged-Current $ν_e$ Interactions Without Visible Pions Across Multiple Kinematic Observables in MicroBooNE

The (MicroBooNE Collaboration)* & MicroBooNE collaborations Abratenko, P. ; Aldana, D. Andrade ; Arellano, L. ; et al.
Phys.Rev.Lett. 135 (2025) 081802, 2025.
Inspire Record 2861683 DOI 10.17182/hepdata.159762

This Letter presents an investigation of low-energy electron-neutrino interactions in the Fermilab Booster Neutrino Beam by the MicroBooNE experiment, motivated by the excess of electron-neutrino-like events observed by the MiniBooNE experiment. This is the first measurement to use data from all five years of operation of the MicroBooNE experiment, corresponding to an exposure of $1.11\times 10^{21}$ protons on target, a $70\%$ increase on past results. Two samples of electron neutrino interactions without visible pions are used, one with visible protons and one without any visible protons. The MicroBooNE data show reasonable agreement with the nominal prediction, with $p$-values $\ge 26.7\%$ when the two $ν_e$ samples are combined, though the prediction exceeds the data in limited regions of phase space. The data is further compared to two empirical models that modify the predicted rate of electron-neutrino interactions in different variables in the simulation to match the unfolded MiniBooNE low energy excess. In the first model, this unfolding is performed as a function of electron neutrino energy, while the second model aims to match the observed shower energy and angle distributions of the MiniBooNE excess. This measurement excludes an electron-like interpretation of the MiniBooNE excess based on these models at $> 99\%$ CL$_\mathrm{s}$ in all kinematic variables.

19 data tables

Fig. 2 top figure - Distributions of MC simulation compared with data for reconstructed neutrino energy in the 1$e$N$p$0$\pi$ signal channel, along with the LEE Signal Model 1. Only bins between 0.15 GeV and 1.55 GeV are released, as statistical tests are performed within this region. The signal and background event categories are summed to form the unconstrained prediction (excluding LEE). Signal events correspond to $\nu_e$ CC events. Background events include $\nu$ with $\pi^0$ events, $\nu$ other events, and cosmic ray events. In Fig. 2, the LEE component is plotted on top of the constrained prediction (excluding LEE) for illustrative purposes. In all statistical tests (results summarized in Table I), the prediction under an LEE hypothesis corresponds to a constrained prediction including LEE. The statistical uncertainties of data use a combined Neyman-Pearson (CNP) version (Eq.(19) in https://doi.org/10.1016/j.nima.2020.163677).

Fig. 2 bottom figure - Distributions of MC simulation compared with data for reconstructed neutrino energy in the 1$e$0$p$0$\pi$ signal channel, along with the LEE Signal Model 1. Only bins between 0.15 GeV and 1.55 GeV are released, as statistical tests are performed within this region. The signal and background event categories are summed to form the unconstrained prediction (excluding LEE). Signal events correspond to $\nu_e$ CC events. Background events include $\nu$ with $\pi^0$ events, $\nu$ other events, and cosmic ray events. In Fig. 2, the LEE component is plotted on top of the constrained prediction (excluding LEE) for illustrative purposes. In all statistical tests (results summarized in Table I), the prediction under an LEE hypothesis corresponds to a constrained prediction including LEE. The statistical uncertainties of data use a combined Neyman-Pearson (CNP) version (Eq.(19) in https://doi.org/10.1016/j.nima.2020.163677).

Fig. 3 top figure - Distributions of MC simulation compared with data for reconstructed shower energy in the 1$e$N$p$0$\pi$ signal channel, along with the LEE Signal Model 2. The signal and background event categories are summed to form the unconstrained prediction (excluding LEE). Signal events correspond to $\nu_e$ CC events. Background events include $\nu$ with $\pi^0$ events, $\nu$ other events, and cosmic ray events. In Fig. 3, the LEE component is plotted on top of the constrained prediction (excluding LEE) for illustrative purposes. In all statistical tests (results summarized in Table I), the prediction under an LEE hypothesis corresponds to a constrained prediction including LEE. The statistical uncertainties of data use a combined Neyman-Pearson (CNP) version (Eq.(19) in https://doi.org/10.1016/j.nima.2020.163677).

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Search for high-mass resonances in final states with a $\tau$-lepton and missing transverse momentum with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abbott, Dale ; et al.
Phys.Rev.D 109 (2024) 112008, 2024.
Inspire Record 2762382 DOI 10.17182/hepdata.146026

A search for high-mass resonances decaying into a $\tau$-lepton and a neutrino using proton-proton collisions at a center-of-mass energy of $\sqrt{s}=13$ TeV is presented. The full Run 2 data sample corresponding to an integrated luminosity of 139 fb$^{-1}$ recorded by the ATLAS experiment in the years 2015-2018 is analyzed. The $\tau$-lepton is reconstructed in its hadronic decay modes and the total transverse momentum carried out by neutrinos is inferred from the reconstructed missing transverse momentum. The search for new physics is performed on the transverse mass between the $\tau$-lepton and the missing transverse momentum. No excess of events above the Standard Model expectation is observed and upper exclusion limits are set on the $W^\prime\to \tau \nu$ production cross-section. Heavy $W^\prime$ vector bosons with masses up to 5.0 TeV are excluded at 95% confidence level, assuming that they have the same couplings as the Standard Model $W$ boson. For non-universal couplings, $W^\prime$ bosons are excluded for masses less than 3.5-5.0 TeV, depending on the model parameters. In addition, model-independent limits on the visible cross-section times branching ratio are determined as a function of the lower threshold on the transverse mass of the $\tau$-lepton and missing transverse momentum.

8 data tables

Observed and predicted $m_{\rm T}$ distributions including SSM and NU (cot$\theta$ = 5.5) $W^{\prime}$ signals with masses of 4 TeV. Please note that in the paper figure the bin content is divided by the bin width, but this is not done in the HepData table.

Observed and expected 95% CL upper limits on cross section times $\tau\nu$ branching fraction for $W^{\prime}_{\rm SSM}$.

Regions of the non-universal parameter space excluded at 95% CL.

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Search for quantum black hole production in lepton+jet final states using proton-proton collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abbott, Dale ; et al.
Phys.Rev.D 109 (2024) 032010, 2024.
Inspire Record 2682338 DOI 10.17182/hepdata.141896

A search for quantum black holes in electron+jet and muon+jet invariant mass spectra is performed with 140 fb$^{-1}$ of data collected by the ATLAS detector in proton-proton collisions at $\sqrt{s}$ = 13 TeV at the Large Hadron Collider. The observed invariant mass spectrum of lepton+jet pairs is consistent with Standard Model expectations. Upper limits are set at 95% confidence level on the production cross-sections times branching fractions for quantum black holes decaying into a lepton and a quark in a search region with invariant mass above 2.0 TeV. The resulting quantum black hole lower mass threshold limit is 9.2 TeV in the Arkani-Hamed-Dimopoulos-Dvali model, and 6.8 TeV in the Randall-Sundrum model.

3 data tables

The 95% CL model-independent upper limits on $\sigma \times Br$ for the non-SM signal production with decay into the lepton+jet. The limits take into account statistical and systematic uncertainties. Circles along the solid red line indicate the lower border of the SR (threshold of SR, Th$_\mathrm{SR}$), above which the observed limit is computed. The expected limits are shown by the dashed line. The $\pm 1\sigma$ and $\pm 2\sigma$ bands of expected limits are shown in green and yellow, respectively. The limits are obtained with pseudo-experiments.

The combined 95% CL upper limits on $\sigma \times Br$ as a function of threshold mass, $M_\mathrm{th}$, for QBH production with decay into lepton+jet for ADD-model (extra dimensions n = 6). The limits take into account statistical and systematic uncertainties. Circles along the solid red line indicate the mass $M_\mathrm{th}$ of the signal where the observed limit is computed. The expected limits are shown by the dashed line. The $\pm 1\sigma$ and $\pm 2\sigma$ bands are shown in green and yellow, respectively. The theoretically predicted $\sigma \times Br$ for the QBH production and decay is shown as the solid blue curve with squares.

The combined 95% CL upper limits on $\sigma \times Br$ as a function of threshold mass, $M_\mathrm{th}$, for QBH production with decay into lepton+jet for RS1-model (extra dimensions n = 1). The limits take into account statistical and systematic uncertainties. Circles along the solid red line indicate the mass $M_\mathrm{th}$ of the signal where the observed limit is computed. The expected limits are shown by the dashed line. The $\pm 1\sigma$ and $\pm 2\sigma$ bands are shown in green and yellow, respectively. The theoretically predicted $\sigma \times Br$ for the QBH production and decay is shown as the solid blue curve with squares.


Search for high-mass $W\gamma$ and $Z\gamma$ resonances using hadronic W/Z boson decays from 139 fb$^{-1}$ of $pp$ collisions at $\sqrt{s}=$ 13 TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abbott, Dale ; et al.
JHEP 07 (2023) 125, 2023.
Inspire Record 2653725 DOI 10.17182/hepdata.136027

A search for high-mass charged and neutral bosons decaying to $W\gamma$ and $Z\gamma$ final states is presented in this paper. The analysis uses a data sample of $\sqrt{s} = 13$ TeV proton-proton collisions with an integrated luminosity of 139 fb$^{-1}$ collected by the ATLAS detector during LHC Run 2 operation. The sensitivity of the search is determined using models of the production and decay of spin-1 charged bosons and spin-0/2 neutral bosons. The range of resonance masses explored extends from 1.0 TeV to 6.8 TeV. At these high resonance masses, it is beneficial to target the hadronic decays of the $W$ and $Z$ bosons because of their large branching fractions. The decay products of the high-momentum $W/Z$ bosons are strongly collimated and boosted-boson tagging techniques are employed to improve the sensitivity. No evidence of a signal above the Standard Model backgrounds is observed, and upper limits on the production cross-sections of these bosons times their branching fractions to $W\gamma$ and $Z\gamma$ are derived for various boson production models.

24 data tables

The jet mass distribution of large-$R$ jets originating from the hadronic decay of $W$ and $Z$ bosons produced from the decay of BSM bosons with mass $m_X = 1000$ GeV. The decays simulated are for the production models $q\bar{q}' \to X^{\pm} \to W^{\pm}\gamma$ with a spin-1 resonance $X^{\pm}$ and $gg\to X^0 \to Z\gamma$ with a spin-0 resonance $X^{0}$.

The jet mass distribution of large-$R$ jets originating from the hadronic decay of $W$ and $Z$ bosons produced from the decay of BSM bosons with mass $m_X = 4000$ GeV. The decays simulated are for the production models $q\bar{q'}\to X^{\pm} \to W^{\pm}\gamma$ with a spin-1 resonance $X^{\pm}$ and $gg\to X^0 \to Z\gamma$ with a spin-0 resonance $X^{0}$.

Total efficiencies for the selection of signal events after categorization and application of the tighter photon $E_{\mathrm{T}}^{\gamma}$ selection used to optimize the signal significance spin-0 $gg\to X^0 \to Z\gamma$. In addition to the total efficiency, contributions to the signal selection from each of the separate event categories are shown. The efficiencies calculated from MC samples with $W/Z$ hadronic decays are shown as the points on each curve. The line presents interpolated results.

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Search for a light charged Higgs boson in $t \rightarrow H^{\pm}b$ decays, with $H^{\pm} \rightarrow cb$, in the lepton+jets final state in proton-proton collisions at $\sqrt{s}=13$ TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abbott, D.C. ; et al.
JHEP 09 (2023) 004, 2023.
Inspire Record 2635801 DOI 10.17182/hepdata.135457

A search for a charged Higgs boson, $H^{\pm}$, produced in top-quark decays, $t \rightarrow H^{\pm}b$, is presented. The search targets $H^{\pm}$ decays into a bottom and a charm quark, $H^{\pm} \rightarrow cb$. The analysis focuses on a selection enriched in top-quark pair production, where one top quark decays into a leptonically decaying $W$ boson and a bottom quark, and the other top quark decays into a charged Higgs boson and a bottom quark. This topology leads to a lepton-plus-jets final state, characterised by an isolated electron or muon and at least four jets. The search exploits the high multiplicity of jets containing $b$-hadrons, and deploys a neural network classifier that uses the kinematic differences between the signal and the background. The search uses a dataset of proton-proton collisions collected at a centre-of-mass energy $\sqrt{s}=13$ TeV between 2015 and 2018 with the ATLAS detector at CERN's Large Hadron Collider, amounting to an integrated luminosity of 139 fb$^{-1}$. Observed (expected) 95% confidence-level upper limits between 0.15% (0.09%) and 0.42% (0.25%) are derived for the product of branching fractions $\mathscr{B}(t\rightarrow H^{\pm}b) \times \mathscr{B}(H^{\pm}\rightarrow cb)$ for charged Higgs boson masses between 60 and 160 GeV, assuming the SM production of the top-quark pairs.

4 data tables

The observed 95% CL upper limits on $\mathscr{B}=\mathscr{B}(t\rightarrow H^{\pm}b) \times \mathscr{B}(H^{\pm}\rightarrow cb)$ as a function of $m_{H^{\pm}}$ and the expectation (dashed) under the background-only hypothesis. The inner green and outer yellow shaded bands show the $\pm 1\sigma$ and $\pm 2\sigma$ uncertainties of the expected limits. The exclusion limits are presented for $m_{H^{\pm}}$ between 60 and 160 GeV with 10 GeV $m_{H^{\pm}}$ spacing and linear interpolation between adjacent mass points. Superimposed on the upper limits, the predictions from the 3HDM are shown, corresponding to three benchmark values for the parameters $X$, $Y$, and $Z$

Pre-fit event yields in each of the nine analysis regions. The $H^{\pm}$ signal yields for $m_{H^{\pm}}=130$ GeV and $m_{H^{\pm}}=70$ GeV are normalised to $\mathscr{B}_{\mathrm{ref}}=1\%$. The quoted uncertainties are the sum in quadrature of statistical and systematic uncertainties of the yields, computed taking into account correlations among processes resulting from the data-based $t\bar{t}$ correction procedure.

Post-fit yields in each of the nine analysis regions considered. The total prediction is shown after the fit to data under the signal-plus-background hypothesis assuming $H^{\pm}$ signal with $m_{H^{\pm}}=130$ GeV. The predicted yileds for the $H^{\pm}$ signal with $m_{H^{\pm}}=70$ GeV are also shown for reference. The best fit-values of $\mathscr{B}$ for $H^{\pm}$ signal with $m_{H^{\pm}}=130$ GeV and $m_{H^{\pm}}=70$ GeV are 0.16% and 0.07% respectively. The quoted uncertainties are the sum in quadrature of statistical and systematic uncertainties of the yields, computed taking into account correlations among nuisance parameters and among processes.

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Search for flavor-changing neutral-current couplings between the top quark and the $Z$ boson with LHC Run 2 proton-proton collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abbott, D.C. ; et al.
Phys.Rev.D 108 (2023) 032019, 2023.
Inspire Record 2627201 DOI 10.17182/hepdata.145074

A search for flavor-changing neutral-current couplings between a top quark, an up or charm quark and a $Z$ boson is presented, using proton-proton collision data at $\sqrt{s} = 13$ TeV collected by the ATLAS detector at the Large Hadron Collider. The analyzed dataset corresponds to an integrated luminosity of 139 fb$^{-1}$. The search targets both single-top-quark events produced as $gq\rightarrow tZ$ (with $q = u, c$) and top-quark-pair events, with one top quark decaying through the $t \rightarrow Zq$ channel. The analysis considers events with three leptons (electrons or muons), a $b$-tagged jet, possible additional jets, and missing transverse momentum. The data are found to be consistent with the background-only hypothesis and 95% confidence-level limits on the $t \rightarrow Zq$ branching ratios are set, assuming only tensor operators of the Standard Model effective field theory framework contribute to the $tZq$ vertices. These are $6.2 \times 10^{-5}$ ($13\times 10^{-5}$) for $t\rightarrow Zu$ ($t\rightarrow Zc$) for a left-handed $tZq$ coupling, and $6.6 \times 10^{-5}$ ($12\times 10^{-5}$) in the case of a right-handed coupling. These results are interpreted as 95% CL upper limits on the strength of corresponding couplings, yielding limits for $|C_{uW}^{(13)*}|$ and $|C_{uB}^{(13)*}|$ ($|C_{uW}^{(31)}|$ and $|C_{uB}^{(31)}|$) of 0.15 (0.16), and limits for $|C_{uW}^{(23)*}|$ and $|C_{uB}^{(23)*}|$ ($|C_{uW}^{(32)}|$ and $|C_{uB}^{(32)}|$) of 0.22 (0.21), assuming a new-physics energy scale $\Lambda_\text{NP}$ of 1 TeV.

18 data tables

Summary of the signal strength $\mu$ parameters obtained from the fits to extract LH and RH results for the FCNC tZu and tZc couplings. For the reference branching ratio, the most stringent limits are used.

Observed and expected 95% CL limits on the FCNC $t\rightarrow Zq$ branching ratios and the effective coupling strengths for different vertices and couplings (top eight rows). For the latter, the energy scale is assumed to be $\Lambda_{NP}$ = 1 TeV. The bottom rows show, for the case of the FCNC $t\rightarrow Zu$ branching ratio, the observed and expected 95% CL limits when only one of the two SRs, either SR1 or SR2, and all CRs are included in the likelihood.

Comparison between data and background prediction before the fit (Pre-Fit) for the mass of the SM top-quark candidate in SR1. The uncertainty band includes both the statistical and systematic uncertainties in the background prediction. The four FCNC LH signals are also shown separately, normalized to five times the cross-section corresponding to the most stringent observed branching ratio limits. The first (last) bin in all distributions includes the underflow (overflow). The lower panels show the ratios of the data (Data) to the background prediction (Bkg.).

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Search for pair-production of vector-like quarks in $pp$ collision events at $\sqrt{s}=13$ TeV with at least one leptonically decaying $Z$ boson and a third-generation quark with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abbott, Dale ; et al.
Phys.Lett.B 843 (2023) 138019, 2023.
Inspire Record 2172216 DOI 10.17182/hepdata.134010

A search for the pair-production of vector-like quarks optimized for decays into a $Z$ boson and a third-generation Standard Model quark is presented, using the full Run 2 dataset corresponding to 139 fb$^{-1}$ of $pp$ collisions at $\sqrt{s}=13$ TeV, collected in 2015-2018 with the ATLAS detector at the Large Hadron Collider. The targeted final state is characterized by the presence of a $Z$ boson with high transverse momentum, reconstructed from a pair of same-flavour leptons with opposite-sign charges, as well as by the presence of $b$-tagged jets and high-transverse-momentum large-radius jets reconstructed from calibrated smaller-radius jets. Events with exactly two or at least three leptons are used, which are further categorized by the presence of boosted $W$, $Z$, and Higgs bosons and top quarks. The categorization is performed using a neural-network-based boosted object tagger to enhance the sensitivity to signal relative to the background. No significant excess above the background expectation is observed and exclusion limits at 95% confidence level are set on the masses of the vector-like partners $T$ and $B$ of the top and bottom quarks, respectively. In the singlet model, the limits allow $m_T > 1.27$ TeV and $m_B > 1.20$ TeV. In the doublet model, allowed masses are $m_T > 1.46$ TeV and $m_B >1.32$ TeV. In the case of 100% branching ratio for $T\rightarrow Zt$ and 100% branching ratio for $B\rightarrow Zb$, the limits allow $m_T > 1.60$ TeV and $m_B > 1.42$ TeV, respectively.

17 data tables

Expected and observed lower limits on B masses at 95% CL in the BR plane from the combination of the two analysis channels for all BR configurations when assuming a total BR of 100% for H, W and Z.

Expected and observed lower limits on T masses at 95% CL in the BR plane from the combination of the two analysis channels for all BR configurations when assuming a total BR of 100% for H, W and Z.

Expected and observed combined limits at 95% CL on the production cross-section of vector-like T for 100% $T\rightarrow Zt$.

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