Search for magnetic monopoles and stable particles with high electric charges in $\sqrt{s}=$13 TeV $pp$ collisions with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abeling, Kira ; et al.
JHEP 11 (2023) 112, 2023.
Inspire Record 2686746 DOI 10.17182/hepdata.141286

We present a search for magnetic monopoles and high-electric-charge objects using LHC Run 2 $\sqrt{s} =$13 TeV proton$-$proton collisions recorded by the ATLAS detector. A total integrated luminosity of 138 fb$^{-1}$ was collected by a specialized trigger. No highly ionizing particle candidate was observed. Considering the Drell-Yan and photon-fusion pair production mechanisms as benchmark models, cross-section upper limits are presented for spin-0 and spin-$\frac{1}{2}$ magnetic monopoles of magnetic charge $1g_\textrm{D}$ and $2g_\textrm{D}$ and for high-electric-charge objects of electric charge $20 \leq |z| \leq 100$, for masses between 200 GeV and 4000 GeV. The search improves by approximately a factor of three the previous cross-section limits on the Drell-Yan production of magnetic monopoles and high-electric charge objects. Also, the first ATLAS limits on the photon-fusion pair production mechanism of magnetic monopoles and high-electric-charge objects have been obtained.

64 data tables

Observed 95% CL upper limits on the cross section for all masses and charges of Drell-Yan spin-0 monopoles production as a function of mass for magnetic charges $|g|=1g_D$ and $|g|=2g_D$.

Observed 95% CL upper limits on the cross section for all masses and charges of Drell-Yan spin-1/2 monopoles production as a function of mass for magnetic charges $|g|=1g_D$ and $|g|=2g_D$.

Observed 95% CL upper limits on the cross section for all masses and charges of photon-fusion pair-produced spin-0 monopoles as a function of mass for magnetic charges $|g|=1g_D$ and $|g|=2g_D$.

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A search for new physics in low-energy electron recoils from the first LZ exposure

The LZ collaboration Aalbers, J. ; Akerib, D.S. ; Musalhi, A.K. Al ; et al.
Phys.Rev.D 108 (2023) 072006, 2023.
Inspire Record 2683605 DOI 10.17182/hepdata.144761

The LUX-ZEPLIN (LZ) experiment is a dark matter detector centered on a dual-phase xenon time projection chamber. We report searches for new physics appearing through few-keV-scale electron recoils, using the experiment's first exposure of 60 live days and a fiducial mass of 5.5t. The data are found to be consistent with a background-only hypothesis, and limits are set on models for new physics including solar axion electron coupling, solar neutrino magnetic moment and millicharge, and electron couplings to galactic axion-like particles and hidden photons. Similar limits are set on weakly interacting massive particle (WIMP) dark matter producing signals through ionized atomic states from the Migdal effect.

10 data tables

The SR1 data in the {S1c, log10S2c} space with respect to observed time. Top plot is first half of SR1 containing 178 of the final data set. Bottom plot is second half of SR1 containing 157 events.

Electronic Recoil (ER) detection efficiency evaluated as a function of simulated true ER energy [keVee]. The data contains ER detection efficiency for ROI of study.

The observed 90% C.L upper limit on effective neutrino magnetic moment (\mu_{\nu}[\mu_{B}]) in SR1. The data contains observed upper limit, median sensitivity and 1\sigma and 2\sigma sensitivity range.

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Pursuit of paired dijet resonances in the Run 2 dataset with ATLAS

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abeling, Kira ; et al.
Phys.Rev.D 108 (2023) 112005, 2023.
Inspire Record 2682337 DOI 10.17182/hepdata.140530

New particles with large masses that decay into hadronically interacting particles are predicted by many models of physics beyond the Standard Model. A search for a massive resonance that decays into pairs of dijet resonances is performed using 140 fb$^{-1}$ of proton$-$proton collisions at $\sqrt{s}=13$ TeV recorded by the ATLAS detector during Run 2 of the Large Hadron Collider. Resonances are searched for in the invariant mass of the tetrajet system, and in the average invariant mass of the pair of dijet systems. A data-driven background estimate is obtained by fitting the tetrajet and dijet invariant mass distributions with a four-parameter dijet function and a search for local excesses from resonant production of dijet pairs is performed. No significant excess of events beyond the Standard Model expectation is observed, and upper limits are set on the production cross-sections of new physics scenarios.

74 data tables

The average tetrajet invariant mass distributions in data, along with the fitted background estimates for 0.10 < $\alpha$ < 0.12.

The average tetrajet invariant mass distributions in data, along with the fitted background estimates for 0.12 < $\alpha$ < 0.14.

The average tetrajet invariant mass distributions in data, along with the fitted background estimates for 0.14 < $\alpha$ < 0.16.

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Search for a new heavy scalar particle decaying into a Higgs boson and a new scalar singlet in final states with one or two light leptons and a pair of $\tau$-leptons with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abeling, Kira ; et al.
JHEP 10 (2023) 009, 2023.
Inspire Record 2679289 DOI 10.17182/hepdata.141076

A search for a new heavy scalar particle $X$ decaying into a Standard Model (SM) Higgs boson and a new singlet scalar particle $S$ is presented. The search uses a proton-proton ($pp$) collision data sample with an integrated luminosity of 140 fb$^{-1}$ recorded at a centre-of-mass energy of $\sqrt{s} = 13$ TeV with the ATLAS detector at the Large Hadron Collider. The most sensitive mass parameter space is explored in $X$ mass ranging from 500 to 1500 GeV, with the corresponding $S$ mass in the range 200-500 GeV. The search selects events with two hadronically decaying $\tau$-lepton candidates from $H\to \tau^+\tau^-$ decays and one or two light leptons ($\ell=e,\,\mu$) from $S\to VV$ ($V = W,\,Z$) decays while the remaining $V$ boson decays hadronically or to neutrinos. A multivariate discriminant based on event kinematics is used to separate the signal from the background. No excess is observed beyond the expected SM background and 95% confidence level upper limits between 72 fb and 542 fb are derived on the cross-section $\sigma(pp\to X\to SH)$ assuming the same SM-Higgs boson-like decay branching ratios for the $S\to VV$ decay. Upper limits on the visible cross-sections $\sigma(pp\to X\to SH \to WW\tau\tau)$ and $\sigma(pp\to X\to SH \to ZZ\tau\tau)$ are also set in the ranges 3-26 fb and 6-33 fb, respectively.

6 data tables

Observed and expected 95% CL upper limits are shown for $\sigma(pp\to X\to SH)$ obtained from $WW1\ell2\tau_{\mathrm{had}}$, $WW2\ell2\tau_{\mathrm{had}}$, $ZZ2\ell2\tau_{\mathrm{had}}$, and their combination, as a function of combined $m_{S}$ and $m_{X}$ masses ($m_{S}$+$m_{X}/25$) in GeV.

Observed and expected 95% CL upper limits are shown for $\sigma(pp\to X\to SH\to WW\tau\tau)$ obtained from the combination of $WW1\ell2\tau_{\mathrm{had}}$ and $WW2\ell2\tau_{\mathrm{had}}$ channels, as a function of combined $m_{S}$ and $m_{X}$ masses ($m_{S}$+$m_{X}/25$) in GeV. The NMSSM scans of the allowed cross-sections for $\sigma(pp\to X\to SH\to WW\tau\tau)$ are also compared.

Observed and expected 95% CL upper limits are shown for $\sigma(pp\to X\to SH\to ZZ\tau\tau)$ obtained from $ZZ2\ell2\tau_{\mathrm{had}}$ channel, as a function of combined $m_{S}$ and $m_{X}$ masses ($m_{S}$+$m_{X}/25$) in GeV. The NMSSM scans of the allowed cross-sections for $\sigma(pp\to X\to SH\to ZZ\tau\tau)$ are also compared.

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Search for pair production of squarks or gluinos decaying via sleptons or weak bosons in final states with two same-sign or three leptons with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abeling, Kira ; et al.
JHEP 02 (2024) 107, 2024.
Inspire Record 2673888 DOI 10.17182/hepdata.139720

A search for pair production of squarks or gluinos decaying via sleptons or weak bosons is reported. The search targets a final state with exactly two leptons with same-sign electric charge or at least three leptons without any charge requirement. The analysed data set corresponds to an integrated luminosity of 139 fb$^{-1}$ of proton$-$proton collisions collected at a centre-of-mass energy of 13 TeV with the ATLAS detector at the LHC. Multiple signal regions are defined, targeting several SUSY simplified models yielding the desired final states. A single control region is used to constrain the normalisation of the $WZ$+jets background. No significant excess of events over the Standard Model expectation is observed. The results are interpreted in the context of several supersymmetric models featuring R-parity conservation or R-parity violation, yielding exclusion limits surpassing those from previous searches. In models considering gluino (squark) pair production, gluino (squark) masses up to 2.2 (1.7) TeV are excluded at 95% confidence level.

102 data tables

Observed exclusion limits at 95% CL from Fig 7(a) for $\tilde{g}$ decays into SM gauge bosons and $\tilde{\chi}^{0}_{1}$

Positive one $\sigma$ observed exclusion limits at 95% CL from Fig 7(a) for $\tilde{g}$ decays into SM gauge bosons and $\tilde{\chi}^{0}_{1}$

Negative one $\sigma$ observed exclusion limits at 95% CL from Fig 7(a) for $\tilde{g}$ decays into SM gauge bosons and $\tilde{\chi}^{0}_{1}$

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Search for dark photons in rare $Z$ boson decays with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abeling, Kira ; et al.
Phys.Rev.Lett. 131 (2023) 251801, 2023.
Inspire Record 2668340 DOI 10.17182/hepdata.140310

A search for events with a dark photon produced in association with a dark Higgs boson via rare decays of the Standard Model $Z$ boson is presented, using 139 fb$^{-1}$ of $\sqrt{s} = 13$ TeV proton-proton collision data recorded by the ATLAS detector at the Large Hadron Collider. The dark Higgs boson decays into a pair of dark photons, and at least two of the three dark photons must each decay into a pair of electrons or muons, resulting in at least two same-flavor opposite-charge lepton pairs in the final state. The data are found to be consistent with the background prediction, and upper limits are set on the dark photon's coupling to the dark Higgs boson times the kinetic mixing between the Standard Model photon and the dark photon, $\alpha_{D}\varepsilon^2$, in the dark photon mass range of $[5, 40]$ GeV except for the $\Upsilon$ mass window $[8.8, 11.1]$ GeV. This search explores new parameter space not previously excluded by other experiments.

30 data tables

Observed and expected upper limits at 95% CL on the production cross-section times branching fraction as a function of $m_{A'}$ at dark Higgs boson mass of 20 GeV

Observed and expected upper limits at 95% CL on the production cross-section times branching fraction as a function of $m_{A'}$ at dark Higgs boson mass of 30 GeV

Observed and expected upper limits at 95% CL on the production cross-section times branching fraction as a function of $m_{A'}$ at dark Higgs boson mass of 40 GeV

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Measurements of multijet event isotropies using optimal transport with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abbott, Dale ; et al.
JHEP 10 (2023) 060, 2023.
Inspire Record 2663035 DOI 10.17182/hepdata.110164

A measurement of novel event shapes quantifying the isotropy of collider events is performed in 140 fb$^{-1}$ of proton-proton collisions with $\sqrt s=13$ TeV centre-of-mass energy recorded with the ATLAS detector at CERN's Large Hadron Collider. These event shapes are defined as the Wasserstein distance between collider events and isotropic reference geometries. This distance is evaluated by solving optimal transport problems, using the 'Energy-Mover's Distance'. Isotropic references with cylindrical and circular symmetries are studied, to probe the symmetries of interest at hadron colliders. The novel event-shape observables defined in this way are infrared- and collinear-safe, have improved dynamic range and have greater sensitivity to isotropic radiation patterns than other event shapes. The measured event-shape variables are corrected for detector effects, and presented in inclusive bins of jet multiplicity and the scalar sum of the two leading jets' transverse momenta. The measured distributions are provided as inputs to future Monte Carlo tuning campaigns and other studies probing fundamental properties of QCD and the production of hadronic final states up to the TeV-scale.

75 data tables

IRing2 for HT2>=500 GeV, NJets>=2

IRing2 for HT2>=500 GeV, NJets>=3

IRing2 for HT2>=500 GeV, NJets>=4

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Observation of $WZ\gamma$ production in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abeling, Kira ; et al.
Phys.Rev.Lett. 132 (2024) 021802, 2024.
Inspire Record 2663046 DOI 10.17182/hepdata.144507

This Letter reports the observation of $WZ\gamma$ production and a measurement of its cross-section using 140.1 $\pm$ 1.2 fb$^{-1}$ of proton-proton collision data recorded at a center-of-mass energy of 13 TeV by the ATLAS detector at the Large Hadron Collider. The $WZ\gamma$ production cross-section, with both the $W$ and $Z$ bosons decaying leptonically, $pp \rightarrow WZ\gamma \rightarrow {\ell'}^{\pm}\nu\ell^{+}\ell^{-}\gamma$ ($\ell^{(')} = e, \mu$), is measured in a fiducial phase-space region defined such that the leptons and the photon have high transverse momentum and the photon is isolated. The cross-section is found to be 2.01 $\pm$ 0.30 (stat.) $\pm$ 0.16 (syst) fb. The corresponding Standard Model predicted cross-section calculated at next-to-leading order in perturbative quantum chromodynamics and at leading order in the electroweak coupling constant is 1.50 $\pm$ 0.06 fb. The observed significance of the $WZ\gamma$ signal is 6.3$\sigma$, compared with an expected significance of 5.0$\sigma$.

4 data tables

Events in bins of the photon $p_{\mathrm{T}}^{\gamma}$ in the SR.

Events in bins of the $p_{\mathrm{T}}^{\ell_{1}}$ in the SR.

Events in bins of the $m(\ell\ell)$ in the SR.

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Search for leptoquarks decaying into the b$\tau$ final state in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abeling, Kira ; et al.
JHEP 10 (2023) 001, 2023.
Inspire Record 2662587 DOI 10.17182/hepdata.140957

A search for leptoquarks decaying into the $b\tau$ final state is performed using Run 2 proton-proton collision data from the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb$^{-1}$ at $\sqrt{s} = 13$ TeV recorded by the ATLAS detector. The benchmark models considered in this search are vector leptoquarks with electric charge of 2/3e and scalar leptoquarks with an electric charge of 4/3e. No significant excess above the Standard Model prediction is observed, and 95% confidence level upper limits are set on the cross-section times branching fraction of leptoquarks decaying into $b\tau$. For the vector leptoquark production two models are considered: the Yang-Mills and Minimal coupling models. In the Yang-Mills (Minimal coupling) scenario, vector leptoquarks with a mass below 1.58 (1.35) TeV are excluded for a gauge coupling of 1.0 and below 2.05 (1.99) TeV for a gauge coupling of 2.5. In the case of scalar leptoquarks, masses below 1.28 TeV (1.53 TeV) are excluded for a Yukawa coupling of 1.0 (2.5). Finally, an interpretation of the results with minimal model dependence is performed for each of the signal region categories, and limits on the visible cross-section for beyond the Standard Model processes are provided.

52 data tables

Observed (solid line) and expected (dashed line) 95% CL upper limits on the cross-section of single plus non-resonant plus pair vector LQ production from the combination of the high b-jet $p_{T}$ signal region for the $\tau_\text{lep}\tau_\text{had}$ and $\tau_\text{had}\tau_\text{had}$ channels. [$U_1^{YM}$ model ($\kappa$ = 0) with $\lambda$ = 1.0]

Observed (solid line) and expected (dashed line) 95% CL upper limits on the cross-section of single plus non-resonant plus pair vector LQ production from the combination of the high b-jet $p_{T}$ signal region for the $\tau_\text{lep}\tau_\text{had}$ and $\tau_\text{had}\tau_\text{had}$ channels. [$U_1^{YM}$ model ($\kappa$ = 0) with $\lambda$ = 1.7]

Observed (solid line) and expected (dashed line) 95% CL upper limits on the cross-section of single plus non-resonant plus pair vector LQ production from the combination of the high b-jet $p_{T}$ signal region for the $\tau_\text{lep}\tau_\text{had}$ and $\tau_\text{had}\tau_\text{had}$ channels. [$U_1^{YM}$ model ($\kappa$ = 0) with $\lambda$ = 2.5]

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Search for Majorana neutrinos in same-sign $WW$ scattering events from $pp$ collisions at $\sqrt{s}=13$ TeV

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abeling, Kira ; et al.
Eur.Phys.J.C 83 (2023) 824, 2023.
Inspire Record 2662303 DOI 10.17182/hepdata.141494

A search for Majorana neutrinos in same-sign $WW$ scattering events is presented. The analysis uses $\sqrt{s}= 13$ TeV proton-proton collision data with an integrated luminosity of 140 fb$^{-1}$ recorded during 2015-2018 by the ATLAS detector at the Large Hadron Collider. The analysis targets final states including exactly two same-sign muons and at least two hadronic jets well separated in rapidity. The modelling of the main backgrounds, from Standard Model same-sign $WW$ scattering and $WZ$ production, is constrained with data in dedicated signal-depleted control regions. The distribution of the transverse momentum of the second-hardest muon is used to search for signals originating from a heavy Majorana neutrino with a mass between 50 GeV and 20 TeV. No significant excess is observed over the background expectation. The results are interpreted in a benchmark scenario of the Phenomenological Type-I Seesaw model. In addition, the sensitivity to the Weinberg operator is investigated. Upper limits at the 95% confidence level are placed on the squared muon-neutrino-heavy-neutrino mass-mixing matrix element $\vert V_{\mu N} \vert^{2}$ as a function of the heavy Majorana neutrino's mass $m_N$, and on the effective $\mu\mu$ Majorana neutrino mass $|m_{\mu\mu}|$.

2 data tables

Observed and expected 95% CL upper limits on the heavy Majorana neutrino mixing element $\vert V_{\mu N} \vert^{2}$ as a function of $m_N$ in the Phenomenological Type-I Seesaw model.

Cutflow for a selection of signal samples used in this analysis. The flavour-aligned scenario (in which $\vert V_{\mu N} \vert^{2}=1$) is considered for heavy Majorana neutrino samples. The event yields include all correction factors applied to simulation, and is normalised to 140 fb$^{-1}$. The `Skim' selection requires 2 baseline muons and 2 jets satisfying the object definitions described in Section 3 and $m_{jj} > 150$ GeV. Uncertainties are statistical only.