The paper presents a search for supersymmetric particles produced in proton-proton collisions at $\sqrt{s}=$ 13 TeV and decaying into final states with missing transverse momentum and jets originating from charm quarks. The data were taken with the ATLAS detector at the Large Hadron Collider at CERN from 2015 to 2018 and correspond to an integrated luminosity of 139 fb$^{-1}$. No significant excess of events over the expected Standard Model background expectation is observed in optimized signal regions, and limits are set on the production cross-sections of the supersymmetric particles. Pair production of charm squarks or top squarks, each decaying into a charm quark and the lightest supersymmetric particle $\tilde{\chi}^0_1$, is excluded at 95% confidence level for squarks with masses up to 900 GeV for scenarios where the mass of $\tilde{\chi}^0_1$ is below 50 GeV. Additionally, the production of leptoquarks with masses up to 900 GeV is excluded for the scenario where up-type leptoquarks decay into a charm quark and a neutrino. Model-independent limits on cross-sections and event yields for processes beyond the Standard Model are also reported.
Summary of material in this HEPData record. <br/><br/> Truth Code snippets, SLHA files, Madgraph process cards and UFO files for the leptoquark models are available under "Additional Resources" (purple button on the left). <br/><br/> <b>Contours:</b> <ul> SUSY exclusion limits (best-expected SR combination) <ul> <a href="155678?version=1&table=Contour1">Expected</a> <a href="155678?version=1&table=Contour3">+1$\sigma$</a> <a href="155678?version=1&table=Contour2">-1$\sigma$</a> <br/> <a href="155678?version=1&table=Contour4">Observed</a> <a href="155678?version=1&table=Contour5">+1$\sigma$</a> <a href="155678?version=1&table=Contour6">-1$\sigma$</a> <br/> </ul> SUSY exclusion limits (best-expected SR combination) as a function of $\Delta m(\tilde{t}_1,\tilde{\chi}_1^0)$ <ul> <a href="155678?version=1&table=Contour7">Expected</a> <a href="155678?version=1&table=Contour9">+1$\sigma$</a> <a href="155678?version=1&table=Contour8">-1$\sigma$</a> <br/> <a href="155678?version=1&table=Contour10">Observed</a> <a href="155678?version=1&table=Contour11">+1$\sigma$</a> <a href="155678?version=1&table=Contour12">-1$\sigma$</a> <br/> </ul> SUSY exclusion limits (SR-HM1) <ul> <a href="155678?version=1&table=Contour15">Expected</a> <a href="155678?version=1&table=Contour14">+1$\sigma$</a> <a href="155678?version=1&table=Contour13">-1$\sigma$</a> <br/> <a href="155678?version=1&table=Contour18">Observed</a> <a href="155678?version=1&table=Contour16">+1$\sigma$</a> <a href="155678?version=1&table=Contour17">-1$\sigma$</a> <br/> </ul> SUSY exclusion limits (SR-HM2) <ul> <a href="155678?version=1&table=Contour21">Expected</a> <a href="155678?version=1&table=Contour20">+1$\sigma$</a> <a href="155678?version=1&table=Contour19">-1$\sigma$</a> <br/> <a href="155678?version=1&table=Contour24">Observed</a> <a href="155678?version=1&table=Contour22">+1$\sigma$</a> <a href="155678?version=1&table=Contour23">-1$\sigma$</a> <br/> </ul> SUSY exclusion limits (SR-HM3) <ul> <a href="155678?version=1&table=Contour27">Expected</a> <a href="155678?version=1&table=Contour26">+1$\sigma$</a> <a href="155678?version=1&table=Contour25">-1$\sigma$</a> <br/> <a href="155678?version=1&table=Contour30">Observed</a> <a href="155678?version=1&table=Contour28">+1$\sigma$</a> <a href="155678?version=1&table=Contour29">-1$\sigma$</a> <br/> </ul> SUSY exclusion limits (SR-Comp1) <ul> <a href="155678?version=1&table=Contour33">Expected</a> <a href="155678?version=1&table=Contour32">+1$\sigma$</a> <a href="155678?version=1&table=Contour31">-1$\sigma$</a> <br/> <a href="155678?version=1&table=Contour36">Observed</a> <a href="155678?version=1&table=Contour34">+1$\sigma$</a> <a href="155678?version=1&table=Contour35">-1$\sigma$</a> <br/> </ul> SUSY exclusion limits (SR-Comp2) <ul> <a href="155678?version=1&table=Contour39">Expected</a> <a href="155678?version=1&table=Contour38">+1$\sigma$</a> <a href="155678?version=1&table=Contour37">-1$\sigma$</a> <br/> <a href="155678?version=1&table=Contour42">Observed</a> <a href="155678?version=1&table=Contour40">+1$\sigma$</a> <a href="155678?version=1&table=Contour41">-1$\sigma$</a> <br/> </ul> SUSY exclusion limits (SR-Comp3) <ul> <a href="155678?version=1&table=Contour45">Expected</a> <a href="155678?version=1&table=Contour44">+1$\sigma$</a> <a href="155678?version=1&table=Contour43">-1$\sigma$</a> <br/> <a href="155678?version=1&table=Contour48">Observed</a> <a href="155678?version=1&table=Contour46">+1$\sigma$</a> <a href="155678?version=1&table=Contour47">-1$\sigma$</a> <br/> </ul> SUSY exclusion limits (SR-Comp-1c) <ul> <a href="155678?version=1&table=Contour50">Expected</a> <a href="155678?version=1&table=Contour49">-1$\sigma$</a> <br/> </ul> SUSY exclusion limits (scan over branching fraction for $m(\tilde{\chi}_1^0)=1$ GeV) <ul> <a href="155678?version=1&table=Contour51">Expected</a> <a href="155678?version=1&table=Contour53">+1$\sigma$</a> <a href="155678?version=1&table=Contour52">-1$\sigma$</a> <br/> <a href="155678?version=1&table=Contour54">Observed</a> <a href="155678?version=1&table=Contour55">+1$\sigma$</a> <a href="155678?version=1&table=Contour56">-1$\sigma$</a> <br/> </ul> SUSY exclusion limits (scan over branching fraction for $m(\tilde{\chi}_1^0)=200$ GeV) <ul> <a href="155678?version=1&table=Contour57">Expected</a> <a href="155678?version=1&table=Contour59">+1$\sigma$</a> <a href="155678?version=1&table=Contour58">-1$\sigma$</a> <br/> <a href="155678?version=1&table=Contour60">Observed</a> <a href="155678?version=1&table=Contour61">+1$\sigma$</a> <a href="155678?version=1&table=Contour62">-1$\sigma$</a> <br/> </ul> $\mathrm{LQ}^\mathrm{u}_{21}$ exclusion limits <ul> <a href="155678?version=1&table=Contour65">Expected</a> <a href="155678?version=1&table=Contour64">+1$\sigma$</a> <a href="155678?version=1&table=Contour63">-1$\sigma$</a> <br/> <a href="155678?version=1&table=Contour68">Observed</a> <a href="155678?version=1&table=Contour66">+1$\sigma$</a> <a href="155678?version=1&table=Contour67">-1$\sigma$</a> <br/> </ul> $\mathrm{LQ}^\mathrm{u}_{22}$ exclusion limits <ul> <a href="155678?version=1&table=Contour71">Expected</a> <a href="155678?version=1&table=Contour70">+1$\sigma$</a> <a href="155678?version=1&table=Contour69">-1$\sigma$</a> <br/> <a href="155678?version=1&table=Contour74">Observed</a> <a href="155678?version=1&table=Contour72">+1$\sigma$</a> <a href="155678?version=1&table=Contour73">-1$\sigma$</a> <br/> </ul> </ul> <b>Cross-section upper limits:</b> <ul> SUSY signals (best-expected SR combination): <a href="155678?version=1&table=Cross-sectionupperlimit1">Observed</a> <br/> $\mathrm{LQ}^\mathrm{u}_{21}$ (combined High-Mass SRs): <a href="155678?version=1&table=Cross-sectionupperlimit2">Observed</a> <br/> $\mathrm{LQ}^\mathrm{u}_{22}$ (combined High-Mass SRs): <a href="155678?version=1&table=Cross-sectionupperlimit3">Observed</a> <br/> $U(1)$ pair (min) (combined High-Mass SRs): <a href="155678?version=1&table=Cross-sectionupperlimit6">Expected</a> <a href="155678?version=1&table=Cross-sectionupperlimit5">+1$\sigma$</a> <a href="155678?version=1&table=Cross-sectionupperlimit4">-1$\sigma$</a> <a href="155678?version=1&table=Cross-sectionupperlimit7">Observed</a> <br/> $U(1)$ pair (YM) (combined High-Mass SRs): <a href="155678?version=1&table=Cross-sectionupperlimit10">Expected</a> <a href="155678?version=1&table=Cross-sectionupperlimit9">+1$\sigma$</a> <a href="155678?version=1&table=Cross-sectionupperlimit8">-1$\sigma$</a> <a href="155678?version=1&table=Cross-sectionupperlimit11">Observed</a> <br/> </ul> <b>Signal region distributions:</b> <ul> <a href="155678?version=1&table=SRdistribution2">$E_\mathrm{T}^\mathrm{miss}$ Sig. in SR-HM1</a> <br/> <a href="155678?version=1&table=SRdistribution3">$m_\mathrm{T}^\mathrm{min}(c)$ in SR-HM2</a> <br/> <a href="155678?version=1&table=SRdistribution4">$R_\mathrm{ISR}$ in SR-Comp1</a> <br/> <a href="155678?version=1&table=SRdistribution5">$R_\mathrm{ISR}$ in SR-Comp2</a> <br/> <a href="155678?version=1&table=SRdistribution6">$R_\mathrm{ISR}$ in SR-Comp3</a> <br/> <a href="155678?version=1&table=SRdistribution1">$R_\mathrm{ISR}$ in SR-Comp-1c</a> <br/> </ul> <b>Acceptances:</b> <ul> SUSY signals: <a href="155678?version=1&table=Acceptance2">SR-HM1</a> <a href="155678?version=1&table=Acceptance3">SR-HM2</a> <a href="155678?version=1&table=Acceptance4">SR-HM3</a> <a href="155678?version=1&table=Acceptance5">SR-HM-Disc</a> <a href="155678?version=1&table=Acceptance6">SR-Comp1</a> <a href="155678?version=1&table=Acceptance7">SR-Comp2</a> <a href="155678?version=1&table=Acceptance8">SR-Comp3</a> <a href="155678?version=1&table=Acceptance1">SR-Comp-1c</a> <br/> $\mathrm{LQ}^\mathrm{u}_{21}$: <a href="155678?version=1&table=Acceptance9">SR-HM1</a> <a href="155678?version=1&table=Acceptance10">SR-HM2</a> <a href="155678?version=1&table=Acceptance11">SR-HM3</a> <a href="155678?version=1&table=Acceptance12">SR-HM-Disc</a> <br/> $\mathrm{LQ}^\mathrm{u}_{22}$: <a href="155678?version=1&table=Acceptance13">SR-HM1</a> <a href="155678?version=1&table=Acceptance14">SR-HM2</a> <a href="155678?version=1&table=Acceptance15">SR-HM3</a> <a href="155678?version=1&table=Acceptance16">SR-HM-Disc</a> <br/> $U(1)$ pair (min): <a href="155678?version=1&table=Acceptance17">SR-HM1</a> <a href="155678?version=1&table=Acceptance18">SR-HM2</a> <a href="155678?version=1&table=Acceptance19">SR-HM3</a> <a href="155678?version=1&table=Acceptance20">SR-HM-Disc</a> <br/> $U(1)$ pair (YM): <a href="155678?version=1&table=Acceptance21">SR-HM1</a> <a href="155678?version=1&table=Acceptance22">SR-HM2</a> <a href="155678?version=1&table=Acceptance23">SR-HM3</a> <a href="155678?version=1&table=Acceptance24">SR-HM-Disc</a> <br/> </ul> <b>Efficiencies:</b> <ul> $U(1)$ pair (min): <a href="155678?version=1&table=Efficiency1">SR-HM1</a> <a href="155678?version=1&table=Efficiency2">SR-HM2</a> <a href="155678?version=1&table=Efficiency3">SR-HM3</a> <a href="155678?version=1&table=Efficiency4">SR-HM-Disc</a> <br/> $U(1)$ pair (YM): <a href="155678?version=1&table=Efficiency5">SR-HM1</a> <a href="155678?version=1&table=Efficiency6">SR-HM2</a> <a href="155678?version=1&table=Efficiency7">SR-HM3</a> <a href="155678?version=1&table=Efficiency8">SR-HM-Disc</a> <br/> </ul> <b>Acceptance times efficiency:</b> <ul> SUSY signals: <a href="155678?version=1&table=Acceptancetimesefficiency2">SR-HM1</a> <a href="155678?version=1&table=Acceptancetimesefficiency3">SR-HM2</a> <a href="155678?version=1&table=Acceptancetimesefficiency4">SR-HM3</a> <a href="155678?version=1&table=Acceptancetimesefficiency5">SR-HM-Disc</a> <a href="155678?version=1&table=Acceptancetimesefficiency6">SR-Comp1</a> <a href="155678?version=1&table=Acceptancetimesefficiency7">SR-Comp2</a> <a href="155678?version=1&table=Acceptancetimesefficiency8">SR-Comp3</a> <a href="155678?version=1&table=Acceptancetimesefficiency1">SR-Comp-1c</a> <br/> $\mathrm{LQ}^\mathrm{u}_{21}$: <a href="155678?version=1&table=Acceptancetimesefficiency9">SR-HM1</a> <a href="155678?version=1&table=Acceptancetimesefficiency10">SR-HM2</a> <a href="155678?version=1&table=Acceptancetimesefficiency11">SR-HM3</a> <a href="155678?version=1&table=Acceptancetimesefficiency12">SR-HM-Disc</a> <br/> $\mathrm{LQ}^\mathrm{u}_{22}$: <a href="155678?version=1&table=Acceptancetimesefficiency13">SR-HM1</a> <a href="155678?version=1&table=Acceptancetimesefficiency14">SR-HM2</a> <a href="155678?version=1&table=Acceptancetimesefficiency15">SR-HM3</a> <a href="155678?version=1&table=Acceptancetimesefficiency16">SR-HM-Disc</a> <br/> $U(1)$ pair (min): <a href="155678?version=1&table=Acceptancetimesefficiency17">SR-HM1</a> <a href="155678?version=1&table=Acceptancetimesefficiency18">SR-HM2</a> <a href="155678?version=1&table=Acceptancetimesefficiency19">SR-HM3</a> <a href="155678?version=1&table=Acceptancetimesefficiency20">SR-HM-Disc</a> <br/> $U(1)$ pair (YM): <a href="155678?version=1&table=Acceptancetimesefficiency21">SR-HM1</a> <a href="155678?version=1&table=Acceptancetimesefficiency22">SR-HM2</a> <a href="155678?version=1&table=Acceptancetimesefficiency23">SR-HM3</a> <a href="155678?version=1&table=Acceptancetimesefficiency24">SR-HM-Disc</a> <br/> </ul> <b>Cutflow:</b> <ul> SUSY benchmarks: <a href="155678?version=1&table=Cutflow5">SR-HM1</a> <a href="155678?version=1&table=Cutflow6">SR-HM2</a> <a href="155678?version=1&table=Cutflow7">SR-HM3</a> <a href="155678?version=1&table=Cutflow8">SR-HM-Disc</a> <a href="155678?version=1&table=Cutflow2">SR-Comp1</a> <a href="155678?version=1&table=Cutflow3">SR-Comp2</a> <a href="155678?version=1&table=Cutflow4">SR-Comp3</a> <a href="155678?version=1&table=Cutflow1">SR-Comp-1c</a> <br/> LQ benchmarks: <a href="155678?version=1&table=Cutflow9">SR-HM1</a> <a href="155678?version=1&table=Cutflow10">SR-HM2</a> <a href="155678?version=1&table=Cutflow11">SR-HM3</a> <a href="155678?version=1&table=Cutflow12">SR-HM-Disc</a> <br/> </ul>
Expected exclusion limit at 95% CL for pair production of top squarks decaying to charm quarks and neutralinos.
Expected exclusion limit $(-1\sigma)$ at 95% CL for pair production of top squarks decaying to charm quarks and neutralinos.
A search for pair-produced scalar and vector leptoquarks decaying into quarks and leptons of different generations is presented. It uses the full LHC Run 2 (2015-2018) data set of 139 fb$^{-1}$ collected with the ATLAS detector in proton-proton collisions at a centre-of-mass energy of $\sqrt{s} = 13$ TeV. Scalar leptoquarks with charge -(1/3)e as well as scalar and vector leptoquarks with charge +(2/3)e are considered. All possible decays of the pair-produced leptoquarks into quarks of the third generation (t, b) and charged or neutral leptons of the first or second generation ($e, \mu, \nu$) with exactly one electron or muon in the final state are investigated. No significant deviations from the Standard Model expectation are observed. Upper limits on the production cross-section are provided for eight models as a function of the leptoquark mass and the branching ratio of the leptoquark into the charged or neutral lepton. In addition, lower limits on the leptoquark masses are derived for all models across a range of branching ratios. Two of these models have the goal of providing an explanation for the recent B-anomalies. In both models, a vector leptoquark decays into charged and neutral leptons of the second generation with a similar branching fraction. Lower limits of 1980 GeV and 1710 GeV are set on the leptoquark mass for these two models.
- - - - - - - - Overview of HEPData Record - - - - - - - - <br/><br/> <b>95% CL limits on the production cross-section for:</b> <ul> <li><a href="135703?version=1&table=%24LQ_u%20%5Crightarrow%20t%5Cnu%2Fb%5Cmu%24%20observed%20limits">scalar up-type LQs decaying into a top quark and a neutrino or a bottom quark and a muon (observed)</a> <li><a href="135703?version=1&table=%24LQ_u%20%5Crightarrow%20t%5Cnu%2Fb%5Cmu%24%20expected%20limits">scalar up-type LQs decaying into a top quark and a neutrino or a bottom quark and a muon (expected)</a> <li><a href="135703?version=1&table=%24LQ_u%20%5Crightarrow%20t%5Cnu%2Fbe%24%20observed%20limits">scalar up-type LQs decaying into a top quark and a neutrino or a bottom quark and an electron (observed)</a> <li><a href="135703?version=1&table=%24LQ_u%20%5Crightarrow%20t%5Cnu%2Fbe%24%20expected%20limits">scalar up-type LQs decaying into a top quark and a neutrino or a bottom quark and an electron (expected)</a> <li><a href="135703?version=1&table=%24LQ_d%20%5Crightarrow%20t%5Cmu%2Fb%5Cnu%24%20observed%20limits">scalar down-type LQs decaying into a bottom quark and a neutrino or a top quark and a muon (observed)</a> <li><a href="135703?version=1&table=%24LQ_d%20%5Crightarrow%20t%5Cmu%2Fb%5Cnu%24%20expected%20limits">scalar down-type LQs decaying into a bottom quark and a neutrino or a top quark and a muon (expected)</a> <li><a href="135703?version=1&table=%24LQ_d%20%5Crightarrow%20te%2Fb%5Cnu%24%20observed%20limits">scalar down-type LQs decaying into a bottom quark and a neutrino or a top quark and an electron (observed)</a> <li><a href="135703?version=1&table=%24LQ_d%20%5Crightarrow%20te%2Fb%5Cnu%24%20expected%20limits">scalar down-type LQs decaying into a bottom quark and a neutrino or a top quark and an electron (expected)</a> <li><a href="135703?version=1&table=%24vLQ_%7BYM%7D%20%5Crightarrow%20t%5Cnu%2Fb%5Cmu%24%20observed%20limits">vector up-type LQs in the Yang-Mills coupling scenario decaying into a top quark and a neutrino or a bottom quark and a muon (observed)</a> <li><a href="135703?version=1&table=%24vLQ_%7BYM%7D%20%5Crightarrow%20t%5Cnu%2Fb%5Cmu%24%20expected%20limits">vector up-type LQs in the Yang-Mills coupling scenario decaying into a top quark and a neutrino or a bottom quark and a muon (expected)</a> <li><a href="135703?version=1&table=%24vLQ_%7BYM%7D%20%5Crightarrow%20t%5Cnu%2Fbe%24%20observed%20limits">vector up-type LQs in the Yang-Mills coupling scenario decaying into a top quark and a neutrino or a bottom quark and an electron (observed)</a> <li><a href="135703?version=1&table=%24vLQ_%7BYM%7D%20%5Crightarrow%20t%5Cnu%2Fbe%24%20expected%20limits">vector up-type LQs in the Yang-Mills coupling scenario decaying into a top quark and a neutrino or a bottom quark and an electron (expected)</a> <li><a href="135703?version=1&table=%24vLQ_%7Bmin%7D%20%5Crightarrow%20t%5Cnu%2Fb%5Cmu%24%20observed%20limits">vector up-type LQs in the minimal coupling scenario decaying into a top quark and a neutrino or a bottom quark and a muon (observed)</a> <li><a href="135703?version=1&table=%24vLQ_%7Bmin%7D%20%5Crightarrow%20t%5Cnu%2Fb%5Cmu%24%20expected%20limits">vector up-type LQs in the minimal coupling scenario decaying into a top quark and a neutrino or a bottom quark and a muon (expected)</a> <li><a href="135703?version=1&table=%24vLQ_%7Bmin%7D%20%5Crightarrow%20t%5Cnu%2Fbe%24%20observed%20limits">vector up-type LQs in the minimal coupling scenario decaying into a top quark and a neutrino or a bottom quark and an electron (observed)</a> <li><a href="135703?version=1&table=%24vLQ_%7Bmin%7D%20%5Crightarrow%20t%5Cnu%2Fbe%24%20expected%20limits">vector up-type LQs in the minimal coupling scenario decaying into a top quark and a neutrino or a bottom quark and an electron (expected)</a> </ul> <b>Product of signal acceptance and efficiency in the training region for:</b> <ul> <li><a href="135703?version=1&table=%24LQ_u%20%5Crightarrow%20t%5Cnu%2Fb%5Cmu%24%20Acceptance%20times%20Efficiency">scalar up-type LQs decaying into top quarks and neutrinos or bottom quarks and muons</a> <li><a href="135703?version=1&table=%24LQ_u%20%5Crightarrow%20t%5Cnu%2Fbe%24%20Acceptance%20times%20Efficiency">scalar up-type LQs decaying into top quarks and neutrinos or bottom quarks and electrons</a> <li><a href="135703?version=1&table=%24LQ_d%20%5Crightarrow%20t%5Cmu%2Fb%5Cnu%24%20Acceptance%20times%20Efficiency">scalar down-type LQs decaying into bottom quarks and neutrinos or top quarks and muons</a> <li><a href="135703?version=1&table=%24LQ_d%20%5Crightarrow%20te%2Fb%5Cnu%24%20Acceptance%20times%20Efficiency">scalar down-type LQs decaying into bottom quarks and neutrinos or top quarks and electrons</a> <li><a href="135703?version=1&table=%24vLQ_%7BYM%7D%20%5Crightarrow%20t%5Cnu%2Fb%5Cmu%24%20Acceptance%20times%20Efficiency">vector up-type LQs in the Yang-Mills coupling scenario decaying into top quarks and neutrinos or bottom quarks and muons</a> <li><a href="135703?version=1&table=%24vLQ_%7BYM%7D%20%5Crightarrow%20t%5Cnu%2Fbe%24%20Acceptance%20times%20Efficiency">vector up-type LQs in the Yang-Mills coupling scenario decaying into top quarks and neutrinos or bottom quarks and electrons</a> <li><a href="135703?version=1&table=%24vLQ_%7Bmin%7D%20%5Crightarrow%20t%5Cnu%2Fb%5Cmu%24%20Acceptance%20times%20Efficiency">vector up-type LQs in the minimal coupling scenario decaying into top quarks and neutrinos or bottom quarks and muons</a> <li><a href="135703?version=1&table=%24vLQ_%7Bmin%7D%20%5Crightarrow%20t%5Cnu%2Fbe%24%20Acceptance%20times%20Efficiency">vector up-type LQs in the minimal coupling scenario decaying into top quarks and neutrinos or bottom quarks and electrons</a> </ul> <b>Cut-flow for:</b> <ul> <li><a href="135703?version=1&table=Scalar%20LQs%20cut-flow">scalar LQs</a> <li><a href="135703?version=1&table=Vector%20LQs%20cut-flow">vector LQs</a> </ul>
Observed 95% CL limits on the production cross-section for scalar up-type LQs decaying into a top quark and a neutrino or a bottom quark and a muon.
Expected 95% CL limits on the production cross-section for scalar up-type LQs decaying into a top quark and a neutrino or a bottom quark and a muon.