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1. Predicting Goal-directed Human Attention Using Inverse Reinforcement Learning

   Yang, Zhibo; Huang, Lihan; Chen, Yupei; Wei, Zijun; Ahn, S.; Samaras, Dimitris; Hoai, Minh (June 2020, IEEE Conference on Computer Vision and Pattern Recognition (CVPR))

   Human gaze behavior prediction is important for behavioral vision and for computer vision applications. Most models mainly focus on predicting free-viewing behavior using saliency maps, but do not generalize to goal-directed behavior, such as when a person searches for a visual target object. We propose the first inverse reinforcement learning (IRL) model to learn the internal reward function and policy used by humans during visual search. We modeled the viewer’s internal belief states as dynamic contextual belief maps of object locations. These maps were learned and then used to predict behavioral scanpaths for multiple target categories. To train and evaluate our IRL model we created COCO-Search18, which is now the largest dataset of highquality search fixations in existence. COCO-Search18 has 10 participants searching for each of 18 target-object categories in 6202 images, making about 300,000 goal-directed fixations. When trained and evaluated on COCO-Search18, the IRL model outperformed baseline models in predicting search fixation scanpaths, both in terms of similarity to human search behavior and search efficiency. Finally, reward maps recovered by the IRL model reveal distinctive targetdependent patterns of object prioritization, which we interpret as a learned object context. 

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2. Search for dark matter produced in association with a single top quark and an energetic W boson in $$\sqrt{s}=$$ 13 TeV $$pp$$ collisions with the ATLAS detector

   https://doi.org/10.1140/epjc/s10052-023-11582-z  

   Aad, G.; Abbott, B.; Abbott, D. C.; Abeling, K.; Abidi, S. H.; Aboulhorma, A.; Abramowicz, H.; Abreu, H.; Abulaiti, Y.; Hoffman, A. C.; et al (July 2023, The European Physical Journal C)

   Abstract This paper presents a search for dark matter,$$\chi $$ $\chi$, using events with a single top quark and an energeticWboson. The analysis is based on proton–proton collision data collected with the ATLAS experiment at$$\sqrt{s}=$$ $\sqrt{s}=$13 TeV during LHC Run 2 (2015–2018), corresponding to an integrated luminosity of 139 fb$$^{-1}$$ ${}^{-1}$. The search considers final states with zero or one charged lepton (electron or muon), at least oneb-jet and large missing transverse momentum. In addition, a result from a previous search considering two-charged-lepton final states is included in the interpretation of the results. The data are found to be in good agreement with the Standard Model predictions and the results are interpreted in terms of 95% confidence-level exclusion limits in the context of a class of dark matter models involving an extended two-Higgs-doublet sector together with a pseudoscalar mediator particle. The search is particularly sensitive to on-shell production of the charged Higgs boson state,$$H^{\pm }$$ $H^{\pm }$, arising from the two-Higgs-doublet mixing, and its semi-invisible decays via the mediator particle,a:$$H^{\pm } \rightarrow W^\pm a (\rightarrow \chi \chi )$$ $H^{\pm }\to W^{\pm }a(\to \chi \chi )$. Signal models with$$H^{\pm }$$ $H^{\pm }$masses up to 1.5 TeV andamasses up to 350 GeV are excluded assuming a$$\tan \beta $$ $tan\beta$value of 1. For masses ofaof 150 (250) GeV,$$\tan \beta $$ $tan\beta$values up to 2 are excluded for$$H^{\pm }$$ $H^{\pm }$masses between 200 (400) GeV and 1.5 TeV. Signals with$$\tan \beta $$ $tan\beta$values between 20 and 30 are excluded for$$H^{\pm }$$ $H^{\pm }$masses between 500 and 800 GeV. 

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3. Search for Higgs boson pair production in association with a vector boson in pp collisions at $$\sqrt{s}=13\,\text {TeV}$$ with the ATLAS detector

   https://doi.org/10.1140/epjc/s10052-023-11559-y  

   Aad, G.; Abbott, B.; Abbott, D. C.; Abeling, K.; Abidi, S. H.; Aboulhorma, A.; Abramowicz, H.; Abreu, H.; Abulaiti, Y.; Hoffman, A. C.; et al (June 2023, The European Physical Journal C)

   Abstract This paper reports a search for Higgs boson pair (hh) production in association with a vector boson ($$W\; {\text {o}r}\; Z$$ $W\text{o}rZ$) using 139 fb$$^{-1}$$ ${}^{-1}$of proton–proton collision data at$$\sqrt{s}=13\,\text {TeV}$$ $\sqrt{s}=13\text{TeV}$recorded with the ATLAS detector at the Large Hadron Collider. The search is performed in final states in which the vector boson decays leptonically ($$W\rightarrow \ell \nu ,\, Z\rightarrow \ell \ell ,\nu \nu $$ $W\to \ell \nu ,Z\to \ell \ell ,\nu \nu$with$$\ell =e, \mu $$ $\ell =e,\mu$) and the Higgs bosons each decay into a pair ofb-quarks. It targetsVhhsignals from both non-resonanthhproduction, present in the Standard Model (SM), and resonanthhproduction, as predicted in some SM extensions. A 95% confidence-level upper limit of 183 (87) times the SM cross-section is observed (expected) for non-resonantVhhproduction when assuming the kinematics are as expected in the SM. Constraints are also placed on Higgs boson coupling modifiers. For the resonant search, upper limits on the production cross-sections are derived for two specific models: one is the production of a vector boson along with a neutral heavy scalar resonanceH, in the mass range 260–1000 GeV, that decays intohh, and the other is the production of a heavier neutral pseudoscalar resonanceAthat decays into aZboson andHboson, where theAboson mass is 360–800 GeV and theHboson mass is 260–400 GeV. Constraints are also derived in the parameter space of two-Higgs-doublet models. 

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4. Search for supersymmetry in final states with missing transverse momentum and three or more b-jets in 139 fb$$^{-1}$$ of proton–proton collisions at $$\sqrt{s} = 13$$ TeV with the ATLAS detector

   https://doi.org/10.1140/epjc/s10052-023-11543-6  

   Aad, G.; Abbott, B.; Abbott, D. C.; Abeling, K.; Abidi, S. H.; Aboulhorma, A.; Abramowicz, H.; Abreu, H.; Abulaiti, Y.; Abusleme Hoffman, A. C.; et al (July 2023, The European Physical Journal C)

   Abstract A search for supersymmetry involving the pair production of gluinos decaying via off-shell third-generation squarks into the lightest neutralino$$(\tilde{\chi }^0_1)$$ $\left({\tilde{\chi }}_1^0\right)$is reported. It exploits LHC proton–proton collision data at a centre-of-mass energy$$\sqrt{s} = 13$$ $\sqrt{s}=13$TeV with an integrated luminosity of 139 fb$$^{-1}$$ ${}^{-1}$collected with the ATLAS detector from 2015 to 2018. The search uses events containing large missing transverse momentum, up to one electron or muon, and several energetic jets, at least three of which must be identified as containingb-hadrons. Both a simple kinematic event selection and an event selection based upon a deep neural-network are used. No significant excess above the predicted background is found. In simplified models involving the pair production of gluinos that decay via off-shell top (bottom) squarks, gluino masses less than 2.44 TeV (2.35 TeV) are excluded at 95% CL for a massless$$\tilde{\chi }^0_1.$$ ${\tilde{\chi }}_1^0.$Limits are also set on the gluino mass in models with variable branching ratios for gluino decays to$$b\bar{b}\tilde{\chi }^0_1,$$ $b\overline{b}{\tilde{\chi }}_1^0,$$$t\bar{t}\tilde{\chi }^0_1$$ $t\overline{t}{\tilde{\chi }}_1^0$and$$t\bar{b}\tilde{\chi }^-_1/\bar{t}b\tilde{\chi }^+_1.$$ $t\overline{b}{\tilde{\chi }}_1^{-}/\overline{t}b{\tilde{\chi }}_1^{+}.$ 

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5. Search for pair-produced vector-like top and bottom partners in events with large missing transverse momentum in pp collisions with the ATLAS detector

   https://doi.org/10.1140/epjc/s10052-023-11790-7  

   Aad, G.; Abbott, B.; Abbott, D. C.; Abeling, K.; Abidi, S. H.; Aboulhorma, A.; Abramowicz, H.; Abreu, H.; Abulaiti, Y.; Abusleme Hoffman, A. C.; et al (August 2023, The European Physical Journal C)

   Abstract A search for pair-produced vector-like quarks using events with exactly one lepton (eor$$\mu $$ $\mu$), at least four jets including at least oneb-tagged jet, and large missing transverse momentum is presented. Data from proton–proton collisions at a centre-of-mass energy of$$\sqrt{s}=$$ $\sqrt{s}=$13 $$\text {TeV}$$ $\text{TeV}$, recorded by the ATLAS detector at the LHC from 2015 to 2018 and corresponding to an integrated luminosity of 139 fb$$^{-1}$$ ${}^{-1}$, are analysed. Vector-like partnersTandBof the top and bottom quarks are considered, as is a vector-likeXwith charge$$+5/3$$ $+5/3$, assuming their decay into aW,Z, or Higgs boson and a third-generation quark. No significant deviations from the Standard Model expectation are observed. Upper limits on the production cross-section ofTandBquark pairs as a function of their mass are derived for various decay branching ratio scenarios. The strongest lower limits on the masses are 1.59 $$\text {TeV}$$ $\text{TeV}$assuming mass-degenerate vector-like quarks and branching ratios corresponding to the weak-isospin doublet model, and 1.47 $$\text {TeV}$$ $\text{TeV}$(1.46 $$\text {TeV}$$ $\text{TeV}$) for exclusive$$T \rightarrow Zt$$ $T\to Zt$($$B/X \rightarrow Wt$$ $B/X\to Wt$) decays. In addition, lower limits on theTandBquark masses are derived for all possible branching ratios. 

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