Search for dark matter produced in association with bottom or top quarks in $\sqrt{s}$ = 13 TeV pp collisions with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
No Journal Information, 2017.
Inspire Record 1633591 DOI 10.17182/hepdata.80080

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and missing transverse momentum are considered. The analysis uses 36.1 $fb^{-1}$ of proton-proton collision data recorded by the ATLAS experiment at $\sqrt{s}$ = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are interpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour-neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross-section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour-charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements.

63 data tables

- - - - - - - - Overview of HEPData Record - - - - - - - - <br/><br/> <b>Systematic uncertainties:</b> <a href="80080?version=1&table=Table2">table</a><br/><br/> <b>Fit results:</b> <a href="80080?version=1&table=Table3">SRb1 and SRb2</a> <a href="80080?version=1&table=Table4">SRt1, SRt2 and SRt3</a><br/><br/> <b>Upper limits:</b> <a href="80080?version=1&table=Table5">table</a><br/><br/> <b>SR distributions:</b> <ul> <li><a href="80080?version=1&table=Table6">SRb1: $E_{\mathrm T}^{\mathrm{miss}}$</a> <li><a href="80080?version=1&table=Table7">SRb2: $\cos{\theta}^*_{bb}$</a> <li><a href="80080?version=1&table=Table8">SRt1: $m_{\mathrm T}^{\mathrm{b,min}}$</a> <li><a href="80080?version=1&table=Table9">SRt2: $E_{\mathrm T}^{\mathrm{miss,sig}}$</a> <li><a href="80080?version=1&table=Table10">SRt3: $\xi^{+}_{\ell\ell}$</a> <li><a href="80080?version=1&table=Table34">SRb1: jet $p_{T}$</a> <li><a href="80080?version=1&table=Table35">SRb2: $H_{\mathrm T}^{ratio}$</a> <li><a href="80080?version=1&table=Table36">SRt1: $\Delta R_{bb}$</a> <li><a href="80080?version=1&table=Table37">SRt2: $M_{\mathrm T}^{b,min}$</a> <li><a href="80080?version=1&table=Table38">SRt3: $\Delta \phi_{boost}$</a> </ul> <b>Exclusion limits:</b> <ul> <li>Scalar SRb2 <a href="80080?version=1&table=Table11">expected</a> <a href="80080?version=1&table=Table12">observed</a> <li>Scalar SRt1/SRt2 <a href="80080?version=1&table=Table13">expected</a> <a href="80080?version=1&table=Table14">observed</a> <li>Scalar SRt3 <a href="80080?version=1&table=Table15">expected</a> <a href="80080?version=1&table=Table16">observed</a> <li>Pseudo-scalar SRb2 <a href="80080?version=1&table=Table17">expected</a> <a href="80080?version=1&table=Table18">observed</a> <li>Pseudo-scalar SRt1/SRt2 <a href="80080?version=1&table=Table19">expected</a> <a href="80080?version=1&table=Table20">observed</a> <li>Pseudo-scalar SRt3 <a href="80080?version=1&table=Table21">expected</a> <a href="80080?version=1&table=Table22">observed</a> <li>Scalar, SRt1/SRt2 vs DM mass <a href="80080?version=1&table=Table23">expected</a> <a href="80080?version=1&table=Table24">observed</a> <li>Scalar, SRt3 vs DM mass <a href="80080?version=1&table=Table25">expected</a> <a href="80080?version=1&table=Table26">observed</a> <li>Pseudo-scalar, SRt1/SRt2 vs DM mass <a href="80080?version=1&table=Table27">expected</a> <a href="80080?version=1&table=Table28">observed</a> <li>Pseudo-scalar, SRt3 vs DM mass <a href="80080?version=1&table=Table29">expected</a> <a href="80080?version=1&table=Table30">observed</a> <li>Colour-charged scalar mediators ($b-$FDM) <a href="80080?version=1&table=Table32">expected</a> <a href="80080?version=1&table=Table33">observed</a> </ul> <b>Direct detection plot:</b> <a href="80080?version=1&table=Table31">table</a><br/><br/> <b>Acceptances:</b> <ul> <li><a href="80080?version=1&table=Table39">SRb1</a> <li><a href="80080?version=1&table=Table41">SRb2 scalar</a> <li><a href="80080?version=1&table=Table44">SRb2 pseudo-scalar</a> <li><a href="80080?version=1&table=Table45">SRt2 scalar</a> <li><a href="80080?version=1&table=Table46">SRt1 scalar</a> <li><a href="80080?version=1&table=Table49">SRt2 pseudo-scalar</a> <li><a href="80080?version=1&table=Table50">SRt1 pseudo-scalar</a> <li><a href="80080?version=1&table=Table53">SRt3 scalar</a> <li><a href="80080?version=1&table=Table55">SRt3 pseudo-scalar</a> </ul> <b>Efficiencies:</b> <ul> <li><a href="80080?version=1&table=Table40">SRb1</a> <li><a href="80080?version=1&table=Table42">SRb2 scalar</a> <li><a href="80080?version=1&table=Table43">SRb2 pseudo-scalar</a> <li><a href="80080?version=1&table=Table47">SRt2 scalar</a> <li><a href="80080?version=1&table=Table48">SRt1 scalar</a> <li><a href="80080?version=1&table=Table51">SRt2 pseudo-scalar</a> <li><a href="80080?version=1&table=Table52">SRt1 pseudo-scalar</a> <li><a href="80080?version=1&table=Table54">SRt3 scalar</a> <li><a href="80080?version=1&table=Table56">SRt3 pseudo-scalar</a> </ul> <b>Cutflows:</b> <ul> <li><a href="80080?version=1&table=Table57">SRb1</a> <li><a href="80080?version=1&table=Table58">SRb2</a> <li><a href="80080?version=1&table=Table59">SRt1 scalar</a> <li><a href="80080?version=1&table=Table60">SRt2 scalar</a> <li><a href="80080?version=1&table=Table61">SRt1 pseudo-scalar</a> <li><a href="80080?version=1&table=Table62">SRt2 pseudo-scalar</a> <li><a href="80080?version=1&table=Table63">SRt3</a> </ul> <b>Truth Code snippets</b> are available under "Resources" (purple button on the left)

Summary of the main systematic uncertainties and their impact on the total SM background prediction in each of the signal regions studied. A range is shown for the four bins composing SRb2 . The total systematic uncertainty can be different from the sum in quadrature of individual sources due to the correlations between them resulting from the fit to the data. The quoted theoretical uncertainties include modelling and cross-section uncertainties.

Fit results in SRb1 and SRb2 for an integrated luminosity of $36.1 fb^{-1}$. The background normalisation parameters are obtained from the background-only fit in the CRs and are applied to the SRs. Small backgrounds are indicated as Others. The dominant component of these smaller background sources in SRb1 is di-boson processes. Benchmark signal models yields are given for each SR. The uncertainties on the yields include all systematic uncertainties.

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Measurement of differential cross sections of isolated-photon plus heavy-flavour jet production in pp collisions at $\sqrt{s}=8$ TeV using the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
No Journal Information, 2017.
Inspire Record 1632756 DOI 10.17182/hepdata.79163

This Letter presents the measurement of differential cross sections of isolated prompt photons produced in association with a b-jet or a c-jet. These final states provide sensitivity to the heavy-flavour content of the proton and aspects related to the modelling of heavy-flavour quarks in perturbative QCD. The measurement uses proton--proton collision data at a centre-of-mass energy of 8 TeV recorded by the ATLAS detector at the LHC in 2012 corresponding to an integrated luminosity of up to 20.2 fb$^{-1}$. The differential cross sections are measured for each jet flavour with respect to the transverse energy of the leading photon in two photon pseudorapidity regions: $|\eta^\gamma|<1.37$ and $1.56<|\eta^\gamma|<2.37$. The measurement covers photon transverse energies $25<E_\textrm{T}^\gamma<400$ GeV and $25<E_\textrm{T}^\gamma<350$ GeV respectively for the two $|\eta^\gamma|$ regions. For each jet flavour, the ratio of the cross sections in the two $|\eta^\gamma|$ regions is also measured. The measurement is corrected for detector effects and compared to leading-order and next-to-leading-order perturbative QCD calculations, based on various treatments and assumptions about the heavy-flavour content of the proton. Overall, the predictions agree well with the measurement, but some deviations are observed at high photon transverse energies. The total uncertainty in the measurement ranges between 13% and 66%, while the central $\gamma+b$ measurement exhibits the smallest uncertainty, ranging from 13% to 27%, which is comparable to the precision of the theoretical predictions.

12 data tables

Measured fiducial integrated $\gamma+b$ and $\gamma+c$ cross sections for $|\eta^\gamma|<1.37$ and $1.56<|\eta^\gamma|<2.37$.

Measured $\gamma+b$ fiducial differential cross section as a function of $E_\text{T}^\gamma$ for $|\eta^\gamma|<1.37$.

Measured $\gamma+b$ fiducial differential cross section as a function of $E_\text{T}^\gamma$ for $1.56<|\eta^\gamma|<2.37$.

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Search for $WW/WZ$ resonance production in $\ell \nu qq$ final states in $pp$ collisions at $\sqrt{s} =$ 13 TeV with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
No Journal Information, 2017.
Inspire Record 1631642 DOI 10.17182/hepdata.79779

A search is conducted for new resonances decaying into a $WW$ or $WZ$ boson pair, where one $W$ boson decays leptonically and the other $W$ or $Z$ boson decays hadronically. It is based on proton-proton collision data with an integrated luminosity of 36.1 fb$^{-1}$ collected with the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of $\sqrt{s}$ = 13 TeV in 2015 and 2016. The search is sensitive to diboson resonance production via vector-boson fusion as well as quark-antiquark annihilation and gluon-gluon fusion mechanisms. No significant excess of events is observed with respect to the Standard Model backgrounds. Several benchmark models are used to interpret the results. Limits on the production cross section are set for a new narrow scalar resonance, a new heavy vector-boson and a spin-2 Kaluza-Klein graviton.

8 data tables
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A search for pair-produced resonances in four-jet final states at $\sqrt{s}$=13 TeV with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
No Journal Information, 2017.
Inspire Record 1631641 DOI 10.17182/hepdata.79059

A search for massive coloured resonances which are pair-produced and decay into two jets is presented. The analysis uses 36.7 fb$^{-1}$ of $\sqrt{s}=$ 13 TeV pp collision data recorded by the ATLAS experiment at the LHC in 2015 and 2016. No significant deviation from the background prediction is observed. Results are interpreted in a SUSY simplified model where the lightest supersymmetric particle is the top squark, $\tilde{t}$, which decays promptly into two quarks through $R$-parity-violating couplings. Top squarks with masses in the range 100 GeV<$m_{\tilde{t}}$<410 GeV are excluded at 95% confidence level. If the decay is into a $b$-quark and a light quark, a dedicated selection requiring two $b$-tags is used to exclude masses in the ranges 100 GeV<$m_{\tilde{t}}$<470 GeV and 480 GeV<$m_{\tilde{t}}$<610 GeV. Additional limits are set on the pair-production of massive colour-octet resonances.

16 data tables

Signal acceptance and efficiency (in %) as a function of M(STOP), before mass windows

Cutflow table for a pair produced top squark of 100 GeV decaying into a b- and an s-quark.

The observed number of data, background and top squark signal events in each of the signal regions of the inclusive selection

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Version 2
A search for $B-L$ $R$-parity-violating top squarks in $\sqrt{s} = 13$ TeV $pp$ collisions with the ATLAS experiment

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
No Journal Information, 2017.
Inspire Record 1630899 DOI 10.17182/hepdata.78376

A search is presented for the direct pair production of the stop, the supersymmetric partner of the top quark, that decays through an $R$-parity-violating coupling to a final state with two leptons and two jets, at least one of which is identified as a $b$-jet. The dataset corresponds to an integrated luminosity of 36.1 fb$^{-1}$ of proton-proton collisions at a center-of-mass energy of $\sqrt{s} = 13$ TeV, collected in 2015 and 2016 by the ATLAS detector at the LHC. No significant excess is observed over the Standard Model background, and exclusion limits are set on stop pair production at a 95% confidence level. Lower limits on the stop mass are set between 600 GeV and 1.5 TeV for branching ratios above 10% for decays to an electron or muon and a $b$-quark.

82 data tables

Expected exclusion limit contour in the (BRe,BRtau) plane for a 600 GeV stop. All limits are computed at 95% CL.

Observed exclusion limit contour in the (BRe,BRtau) plane for a 600 GeV stop. All limits are computed at 95% CL.

Observed exclusion limit in the (BRe,BRtau) plane on the cross section for a 600 GeV stop. All limits are computed at 95% CL.

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Measurement of the Drell--Yan triple-differential cross section in $pp$ collisions at $\sqrt{s} = 8$ TeV

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
No Journal Information, 2017.
Inspire Record 1630886 DOI 10.17182/hepdata.77492

This paper presents a measurement of the triple-differential cross section for the Drell--Yan process $Z/\gamma^*\rightarrow \ell^+\ell^-$ where $\ell$ is an electron or a muon. The measurement is performed for invariant masses of the lepton pairs, $m_{\ell\ell}$, between $46$ and $200$ GeV using a sample of $20.2$ fb$^{-1}$ of $pp$ collisions data at a centre-of-mass energy of $\sqrt{s}=8$ TeV collected by the ATLAS detector at the LHC in 2012. The data are presented in bins of invariant mass, absolute dilepton rapidity, $|y_{\ell\ell}|$, and the angular variable $\cos\theta^{*}$ between the outgoing lepton and the incoming quark in the Collins--Soper frame. The measurements are performed in the range $|y_{\ell\ell}|<2.4$ in the muon channel, and extended to $|y_{\ell\ell}|<3.6$ in the electron channel. The cross sections are used to determine the $Z$ boson forward-backward asymmetry as a function of $|y_{\ell\ell}|$ and $m_{\ell\ell}$. The measurements achieve high-precision, below the percent level in the pole region, excluding the uncertainty in the integrated luminosity, and are in agreement with predictions. These precision data are sensitive to the parton distribution functions and the effective weak mixing angle.

6 data tables

Detailed breakdown of systematic uncertainties for the measurement in the central rapidity muon channel. Common systematic uncertainty on the luminosity measurment of 1.8% is not included. Correlated systematic uncertainties with the suffix :A should be treated as additive and with the suffix :M should be treated as multiplicative. The source 'sys,uncor' represents bin-to-bin uncorrelated systematic uncertainty. The cross sections are given at the Born QED level. 'C Dressed' represents the multiplicative correction factor to translate the cross sections to the dressed level with the cone radius of 0.1: SigmaDressed = C Dressed * SigmaBorn.

Detailed breakdown of systematic uncertainties for the measurement in the central rapidity electron channel. Common systematic uncertainty on the luminosity measurment of 1.8% is not included. Correlated systematic uncertainties with the suffix :A should be treated as additive and with the suffix :M should be treated as multiplicative. The source 'sys,uncor' represents bin-to-bin uncorrelated systematic uncertainty. The cross sections are given at the Born QED level. 'C Dressed' represents the multiplicative correction factor to translate the cross sections to the dressed level with the cone radius of 0.1: SigmaDressed = C Dressed * SigmaBorn.

Detailed breakdown of systematic uncertainties for the measurement in the forward rapidity electron channel. Common systematic uncertainty on the luminosity measurment of 1.8% is not included. Correlated systematic uncertainties with the suffix :A should be treated as additive and with the suffix :M should be treated as multiplicative. The source 'sys,uncor' represents bin-to-bin uncorrelated systematic uncertainty. The cross sections are given at the Born QED level. 'C Dressed' represents the multiplicative correction factor to translate the cross sections to the dressed level with the cone radius of 0.1: SigmaDressed = C Dressed * SigmaBorn.

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Version 2
Search for long-lived, massive particles in events with displaced vertices and missing transverse momentum in $\sqrt{s}$ = 13 TeV $pp$ collisions with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
No Journal Information, 2017.
Inspire Record 1630632 DOI 10.17182/hepdata.78697

A search for long-lived, massive particles predicted by many theories beyond the Standard Model is presented. The search targets final states with large missing transverse momentum and at least one high-mass displaced vertex with five or more tracks, and uses 32.8 fb$^{-1}$ of $\sqrt{s}$ = 13 TeV $pp$ collision data collected by the ATLAS detector at the LHC. The observed yield is consistent with the expected background. The results are used to extract 95\% CL exclusion limits on the production of long-lived gluinos with masses up to 2.37 TeV and lifetimes of $\mathcal{O}(10^{-2})$-$\mathcal{O}(10)$ ns in a simplified model inspired by Split Supersymmetry.

36 data tables

Vertex reconstruction efficiency as a function of radial position $R$ with and without the special LRT processing for one $R$-hadron signal sample with $m_{\tilde{g}} = 1.2$ TeV, $m_{\tilde{\chi}_{1}^{0}} = 100$ GeV and $\tau_{\tilde{g}} = 1$ ns. The efficiency is defined as the probability for a true LLP decay to be matched with a reconstructed DV fulfilling the vertex preselection criteria in events with a reconstructed primary vertex.

Vertex reconstruction efficiency as a function of radial position $R$ for two $R$-hadron signal samples with $m_{\tilde{g}} = 1.2$ TeV, $\tau_{\tilde{g}} = 1$ ns and different neutralino masses. The efficiency is defined as the probability for a true LLP decay to be matched with a reconstructed DV fulfilling the vertex preselection criteria in events with a reconstructed primary vertex.

Fractions of selected events for several signal MC samples with a gluino lifetime $\tau = 1$ ns, illustrating how $\mathcal{A}\times\varepsilon$ varies with the model parameters.

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Search for new phenomena in high-mass final states with a photon and a jet from $pp$ collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
No Journal Information, 2017.
Inspire Record 1627878 DOI 10.17182/hepdata.78551

A search is performed for new phenomena in events having a photon with high transverse momentum and a jet collected in 36.7 fb$^{-1}$ of proton-proton collisions at a centre-of-mass energy of $\sqrt{s}$ = 13 TeV recorded with the ATLAS detector at the Large Hadron Collider. The invariant mass distribution of the leading photon and jet is examined to look for the resonant production of new particles or the presence of new high-mass states beyond the Standard Model. No significant deviation from the background-only hypothesis is observed and cross-section limits for generic Gaussian-shaped resonances are extracted. Excited quarks hypothesized in quark compositeness models and high-mass states predicted in quantum black hole models with extra dimensions are also examined in the analysis. The observed data exclude, at 95% confidence level, the mass range below 5.3 TeV for excited quarks and 7.1 TeV (4.4 TeV) for quantum black holes in the Arkani-Hamed-Dimopoulos-Dvali (Randall-Sundrum) model with six (one) extra dimensions.

6 data tables

Observed 95% CL upper limits on the production cross section times branching ratio to a photon and a quark or gluon for the excited-quarks model.The limits are placed as a function of m_q* for the excited-quark signal. The calculation is performed using ensemble tests for masses in the search range every 250 GeV up to 5 TeV and then 200 GeV up to 6 TeV.

Observed 95% CL upper limits on the production cross section times branching ratio to a photon and a quark or gluon for the RS1 model. The limits are placed as a function of M_th. The calculation is performed using ensemble tests for masses in the search range every 200 GeV.

Observed 95% CL upper limits on the production cross section times branching ratio to a photon and a quark or gluon for the ADD model. The limits are placed as a function of M_th. The calculation is performed using ensemble tests for masses in the search range every 500 GeV.

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Search for additional heavy neutral Higgs and gauge bosons in the ditau final state produced in 36 fb$^{-1}$ of $pp$ collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
No Journal Information, 2017.
Inspire Record 1624690 DOI 10.17182/hepdata.78402

A search for heavy neutral Higgs bosons and $Z^{\prime}$ bosons is performed using a data sample corresponding to an integrated luminosity of 36.1 fb$^{-1}$ from proton-proton collisions at $\sqrt{s}$ = 13 TeV recorded by the ATLAS detector at the LHC during 2015 and 2016. The heavy resonance is assumed to decay to $\tau^+\tau^-$ with at least one tau lepton decaying to final states with hadrons and a neutrino. The search is performed in the mass range of 0.2-2.25 TeV for Higgs bosons and 0.2-4.0 TeV for $Z^{\prime}$ bosons. The data are in good agreement with the background predicted by the Standard Model. The results are interpreted in benchmark scenarios. In the context of the hMSSM scenario, the data exclude $\tan\beta > 1.0$ for $m_A$ = 0.25 TeV and $\tan\beta > 42$ for $m_A$ = 1.5 TeV at the 95% confidence level. For the Sequential Standard Model, $Z^{\prime}_\mathrm{SSM}$ with $m_{Z^{\prime}} < 2.42$ TeV is excluded at 95% confidence level, while $Z^{\prime}_\mathrm{NU}$ with $m_{Z^{\prime}} < 2.25$ TeV is excluded for the non-universal $G(221)$ model that exhibits enhanced couplings to third-generation fermions.

29 data tables

Observed and predicted mTtot distribution in the b-veto category of the 1l1tau_h channel. Despite listing this as an exclusive final state (as there must be no b-jets), there is no explicit selection on the presence of additional light-flavour jets. Please note that the bin content is divided by the bin width in the paper figure, but not in the HepData table. In the paper, the first bin is cut off at 60 GeV for aesthetics but contains underflows down to 50 GeV as in the HepData table. The last bin includes overflows. The combined prediction for A and H bosons with masses of 300, 500 and 800 GeV and $\tan\beta$ = 10 in the hMSSM scenario are also provided.

Observed and predicted mTtot distribution in the b-tag category of the 1l1tau_h channel. Despite listing this as an exclusive final state (as there must be at least one b-jets), there is no explicit selection on the presence of additional light-flavour jets. Please note that the bin content is divided by the bin width in the paper figure, but not in the HepData table. In the paper, the first bin is cut off at 60 GeV for aesthetics but contains underflows down to 50 GeV as in the HepData table. The last bin includes overflows. The combined prediction for A and H bosons with masses of 300, 500 and 800 GeV and $\tan\beta$ = 10 in the hMSSM scenario are also provided.

Observed and predicted mTtot distribution in the b-veto category of the 2tau_h channel. Despite listing this as an exclusive final state (as there must be no b-jets), there is no explicit selection on the presence of additional light-flavour jets. Please note that the bin content is divided by the bin width in the paper figure, but not in the HepData table. The last bin includes overflows. The combined prediction for A and H bosons with masses of 300, 500 and 800 GeV and $\tan\beta$ = 10 in the hMSSM scenario are also provided.

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A search for resonances decaying into a Higgs boson and a new particle $X$ in the $XH \to qqbb$ final state with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
No Journal Information, 2017.
Inspire Record 1624549 DOI 10.17182/hepdata.78568

A search for heavy resonances decaying into a Higgs boson ($H$) and a new particle ($X$) is reported, utilizing 36.1 fb$^{-1}$ of proton--proton collision data at $\sqrt{s} =$ 13 TeV collected during 2015 and 2016 with the ATLAS detector at the CERN Large Hadron Collider. The particle $X$ is assumed to decay to a pair of light quarks, and the fully hadronic final state $XH \rightarrow q\bar q'b\bar b$ is analysed. The search considers the regime of high $XH$ resonance masses, where the $X$ and $H$ bosons are both highly Lorentz-boosted and are each reconstructed using a single jet with large radius parameter. A two-dimensional phase space of $XH$ mass versus $X$ mass is scanned for evidence of a signal, over a range of $XH$ resonance mass values between 1 TeV and 4 TeV, and for $X$ particles with masses from 50 GeV to 1000 GeV. All search results are consistent with the expectations for the background due to Standard Model processes, and 95% CL upper limits are set, as a function of $XH$ and $X$ masses, on the production cross-section of the $XH$ resonance.

90 data tables
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Version 5
Search for a scalar partner of the top quark in the jets plus missing transverse momentum final state at $\sqrt{s}$=13 TeV with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
No Journal Information, 2017.
Inspire Record 1623207 DOI 10.17182/hepdata.79538

A search for pair production of a scalar partner of the top quark in events with four or more jets plus missing transverse momentum is presented. An analysis of 36.1 fb$^{-1}$ of $\sqrt{s}$=13 TeV proton--proton collisions collected using the ATLAS detector at the LHC yields no significant excess over the expected Standard Model background. To interpret the results a simplified supersymmetric model is used where the top squark is assumed to decay via $\tilde{t}_1 \rightarrow t^{(*)} \tilde\chi^0_1$ and $\tilde{t}_1\rightarrow b\tilde\chi^\pm_1 \rightarrow b W^{(*)} \tilde\chi^0_1$, where $\tilde\chi^0_1$ ($\chi^\pm_1$) denotes the lightest neutralino (chargino). Exclusion limits are placed in terms of the top-squark and neutralino masses. Assuming a branching ratio of 100\% to $t \tilde\chi^0_1$, top-squark masses in the range 450--950 GeV are excluded for $\tilde\chi^0_1$ masses below 160 GeV. In the case where $m_{\tilde{t}_1}\sim m_t+m_{\tilde\chi^0_1}$, top-squark masses in the range 235--590 GeV are excluded.

83 data tables

Acceptance for SRA-T0 for top squark pair production in the case where both top squarks decay via $\tilde{t}\to t^{(*)} \tilde{\chi^{0}_{1}}$.

Acceptance for SRA-TT for top squark pair production in the case where both top squarks decay via $\tilde{t}\to t^{(*)} \tilde{\chi^{0}_{1}}$.

Acceptance for SRA-TW for top squark pair production in the case where both top squarks decay via $\tilde{t}\to t^{(*)} \tilde{\chi^{0}_{1}}$.

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Measurement of $\tau$ polarisation in $Z/\gamma^{*}\rightarrow\tau\tau$ decays in proton-proton collisions at $\sqrt{s}=8$ TeV with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
No Journal Information, 2017.
Inspire Record 1622745 DOI 10.17182/hepdata.79418

This paper presents a measurement of the polarisation of $\tau$ leptons produced in $Z/\gamma^{*}\rightarrow\tau\tau$ decays which is performed with a dataset of proton-proton collisions at $\sqrt{s}=8$ TeV, corresponding to an integrated luminosity of 20.2 fb$^{-1}$ recorded with the ATLAS detector at the LHC in 2012. The $Z/\gamma^{*}\rightarrow\tau\tau$ decays are reconstructed from a hadronically decaying $\tau$ lepton with a single charged particle in the final state, accompanied by a $\tau$ lepton that decays leptonically. The $\tau$ polarisation is inferred from the relative fraction of energy carried by charged and neutral hadrons in the hadronic $\tau$ decays. The polarisation is measured in a fiducial region that corresponds to the kinematic region accessible to this analysis. The $\tau$ polarisation extracted over the full phase space within the $Z/\gamma^{*}$ mass range of 66$ < m_{Z/\gamma^{*}} < $ 116 GeV is found to be $P_{\tau} =-0.14 \pm 0.02 (\text{stat}) \pm 0.04 (\text{syst})$. It is in agreement with the Standard Model prediction of $P_{\tau} =-0.1517 \pm 0.0019$, which is obtained from the ALPGEN event generator interfaced with the PYTHIA 6 parton shower modelling and the TAUOLA $\tau$ decay library.

9 data tables

The measured polarisation values (fiducial and extracted to full phase-space) for electron-hadron and muon-hadron channels as well as combined.

Definition of fiducial region of the analysis. The requirements are applied at stable-particle level.

Impact of individual systematic uncertainties on full and fiducial polarisation.

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Searches for heavy $ZZ$ and $ZW$ resonances in the $\ell\ell qq$ and $\nu\nu qq$ final states in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
No Journal Information, 2017.
Inspire Record 1620910 DOI 10.17182/hepdata.78550

This paper reports searches for heavy resonances decaying into $ZZ$ or $ZW$ using data from proton--proton collisions at a centre-of-mass energy of $\sqrt{s}=13$ TeV. The data, corresponding to an integrated luminosity of 36.1 fb$^{-1}$, were recorded with the ATLAS detector in 2015 and 2016 at the Large Hadron Collider. The searches are performed in final states in which one $Z$ boson decays into either a pair of light charged leptons (electrons and muons) or a pair of neutrinos, and the associated $W$ boson or the other $Z$ boson decays hadronically. No evidence of the production of heavy resonances is observed. Upper bounds on the production cross sections of heavy resonances times their decay branching ratios to $ZZ$ or $ZW$ are derived in the mass range 300--5000 GeV within the context of Standard Model extensions with additional Higgs bosons, a heavy vector triplet or warped extra dimensions. Production through gluon--gluon fusion, Drell--Yan or vector-boson fusion are considered, depending on the assumed model.

16 data tables

Selection acceptance times efficiency for ggF H -> Z Z -> llqq as a function of the Higgs boson mass, combining the HP and LP signal regions of the ZV -> llJ selection and the b-tagged and untagged regions of the ZV -> lljj selection.

Selection acceptance times efficiency for VBF H -> Z Z -> llqq as a function of the Higgs boson mass, combining the HP and LP signal regions of the ZV -> llJ selection and the b-tagged and untagged regions of the ZV -> lljj selection.

Selection acceptance times efficiency for ggF H -> Z Z -> vvqq as a function of the Higgs boson mass, combining the HP and LP signal regions.

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Search for supersymmetry in events with $b$-tagged jets and missing transverse momentum in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
No Journal Information, 2017.
Inspire Record 1620694 DOI 10.17182/hepdata.79165

A search for the supersymmetric partners of the Standard Model bottom and top quarks is presented. The search uses 36.1 fb$^{-1}$ of $pp$ collision data at $\sqrt{s}=13$ TeV collected by the ATLAS experiment at the Large Hadron Collider. Direct production of pairs of bottom and top squarks ($\tilde{b}_{1}$ and $\tilde{t}_{1}$) is searched for in final states with $b$-tagged jets and missing transverse momentum. Distinctive selections are defined with either no charged leptons (electrons or muons) in the final state, or one charged lepton. The zero-lepton selection targets models in which the $\tilde{b}_{1}$ is the lightest squark and decays via $\tilde{b}_{1} \rightarrow b \tilde{\chi}^{0}_{1}$, where $\tilde{\chi}^{0}_{1}$ is the lightest neutralino. The one-lepton final state targets models where bottom or top squarks are produced and can decay into multiple channels, $\tilde{b}_{1} \rightarrow b \tilde{\chi}^{0}_{1}$ and $\tilde{b}_{1} \rightarrow t \tilde{\chi}^{\pm}_{1}$, or $\tilde{t}_{1} \rightarrow t \tilde{\chi}^{0}_{1}$ and $\tilde{t}_{1} \rightarrow b \tilde{\chi}^{\pm}_{1}$, where $\tilde{\chi}^{\pm}_{1}$ is the lightest chargino and the mass difference $m_{\tilde{\chi}^{\pm}_{1}}- m_{\tilde{\chi}^{0}_{1}}$ is set to 1 GeV. No excess above the expected Standard Model background is observed. Exclusion limits at 95\% confidence level on the mass of third-generation squarks are derived in various supersymmetry-inspired simplified models.

101 data tables

Expected exclusion limit for b0L-SRA350 for sbottom pair production with symmetric decay into a bottom quark and a neutralino.

Signal acceptance (in %) in the ( M(SBOTTOM), M(NEUTRALINO) ) mass plane for the symmetric decay of the sbottom into bottom quark and neutralino, for the b0L-SRA350 signal region.

b1L signal region with best expected exclusion limit in the ( M(SBOTTOM), M(NEUTRALINO) ) mass plane for the asymmetric decay of the sbottom into bottom quark and neutralino or top quark and chargino.

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Search for squarks and gluinos in events with an isolated lepton, jets and missing transverse momentum at $\sqrt{s}$ = 13 TeV with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
No Journal Information, 2017.
Inspire Record 1620206 DOI 10.17182/hepdata.78218

The results of a search for squarks and gluinos in final states with an isolated electron or muon, multiple jets and large missing transverse momentum using proton--proton collision data at a center-of-mass energy of $\sqrt{s}$ = 13 TeV are presented. The dataset used was recorded during 2015 and 2016 by the ATLAS experiment at the Large Hadron Collider and corresponds to an integrated luminosity of 36.1 $fb^{-1}$. No significant excess beyond the expected background is found. Exclusion limits at 95% confidence level are set in a number of supersymmetric scenarios, reaching masses up to 2.1 TeV for gluino pair production and up to 1.25 TeV for squark pair production.

71 data tables

Observed upper limits on the signal cross-section for gluino one-step x = 1/2 model.

Efficiency in 2J discovery signal region for gluino one-step x = 1/2 model.

$m_{\mathrm{T}}$ distribution for events satisfying all the 2J b-veto signal region selections but for the one on the variable shown in the figure. The uncertainty bands plotted include all statistical and systematic uncertainties. The dashed lines stand for the benchmark signal samples.