“…Then, the search for Higgs pair production, both resonantly and non-resonantly (a process predicted by the Standard Model, albeit at very low rates), in the final state with two bottom quark jets and two photons will be detailed. An important part of these results is the performance of the Compact Muon Solenoid's Electromagnetic Calorimeter, which will also be presented.…”
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“…The cross-section of top-quark pair production in association with a photon in proton-proton collisions at a center of mass energy of $\sqrt{s} = 8~\mathrm{TeV}$ is measured. …”
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“…The analysis looks for an excess of events with large imbalance in transverse momentum and a top quark pair decaying in the dileptonic mode. The results are interpreted in the context of simplified models of dark matter production. …”
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“…Multiple jet substructure variables, such as the particle multiplicity, width, eccentricity, $p_\mathrm{T}$ dispersion, N-subjettiness ratios, generalized angularities, and energy correlation functions, are measured for inclusive jets, as well as for identified bottom, light-quark, and gluon jets from the $\mathrm{t \bar t}$ final state. …”
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“…The measurement of charge particle production in heavy ion collisions, when compared with pp data, provides insight into the properties of the hot and dense quark-gluon plasma. The ATLAS detector at the LHC recorded 0.49 nb$^{−1}$ of Pb+Pb collisions and 4.2 pb$^{−1}$ of pp collisions, both at the center-of-mass energy $\sqrt{s}=\sqrt{s_{NN}}=5.02$ TeV. …”
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“…Electromagnetic processes provide new tools for studying the partonic structure of nuclei, and possibly for directly probing the quark gluon plasma. Ultra-peripheral heavy ion collisions occur when the nuclei have large impact parameter and interact through photon-induced reactions. …”
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“…The flavour non-singlet and singlet quark distributions as well as the gluon distribution are extracted with good precision down to low values of x (0.008). …”
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“…The first study is devoted to the search for a structure in the $B_s^0\pi^\pm$ invariant mass spectrum in the ATLAS detector particularly the search for the resonance X(5568) which is a tetra-quark candidate. The second study is devoted to the search for excited states of the $B^\pm_c$ through its hadronic transition to the ground state, detected in the decay $B^\pm_c\rightarrow J/\psi\pi^\pm$. …”
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“…The measurement of charged-hadron production in heavy-ion collisions provides insight into the properties of the quark-gluon plasma by measuring parton energy loss. …”
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“…This jet energy scale correction consists of multiple steps where features of the reconstructed jet are used se- quentially, in order to improve the resolution and reduce the differences between quark and gluon jets (flavor dependence). This study reports on a new method based on multivari- ate regression, demonstrated with neural networks, that generalizes the current (iterated) one-dimensional technique for performing jet energy scale corrections (numerical inversion), called generalized numerical inversion. …”
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“…Because photons do not carry color charge, they are unaffected by the medium, and thus provide information about the momentum, direction, and flavor (quark or gluon) of the associated hard-scattered parton before it begins to shower and become quenched. …”
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“…This search targets a region of the parameter space where the kinematics of top squark pair production and top quark pair production are very similar, due to the mass of the neutralino being small. …”
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“…Upper limits at the $95\%$ confidence level are set on the production cross section times branching fraction to $\tau^{\pm}\nu_\tau$ for a charged Higgs boson in the mass range from 80 to 3000 GeV, including the mass region near the top quark mass. The observed limit ranges from 6.0 pb at 80 GeV to 0.005 pb at 3 TeV. …”
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“…The measurement of charge-particle production in heavy-ion collision systems and its comparison to $pp$ data provide an insight into the properties of the quark-gluon plasma produced in collisions of heavy ions. …”
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“…The relevance of azimuthal asymmetries lies in the possibility to get information on the intrinsic transverse momentum of the quark as well as on the still unknown Boer-Mulders parton distribution function. …”
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“…Minimizing fine tuning in this solution often puts the superpartners of the Higgs boson (higgsino) and top quark (stop) well within LHC reach. In the most natural scenario, the higgsino and stop masses are expected to be close to the masses of their Standard Model partners. …”
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“…The measurement is performed in the single-lepton channel ($e$ or $\mu$) combining both the resolved and boosted topologies of top quark decays. A Bayesian unfolding procedure is used to infer the asymmetry at parton level, correcting for detector resolution and acceptance effects. …”
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“…Recently collected data by the ATLAS experiment at the LHC offer opportunities to explore dynamic properties of quark-gluon plasma. A new tool to study these properties is the modified Pearson's correlation coefficient, $\rho$. …”
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“…Using the Laplace sum rule (LSR) approach, which is less affected by the contribution of the higher mass hadronic states than the Finite Energy Sum Rule (FESR), we test the reliability of the existing estimate of the K^0-\overline {K}^0 mixing parameter from the four-quark two-point correlator. We obtain, for the renormalization group invariant B-parameter \Big[ f_K/(1.2f_\pi)\Big]^2 \hat {B}_K, the upper bound: 0.83 and the best estimate: 0.55 \pm 0.09. …”
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