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A measurement of the $ZZ$ production in the $\\ell^{-}\\ell^{+}\\ell^{\\prime -}\\ell^{\\prime +}$ and $\\ell^{-}\\ell^{+}\\nu\\bar{\\nu}$ channels $(\\ell = e, \\mu)$ in proton--proton collisions at $\\sqrt{s} = 8$ TeV at the Large Hadron Collider at CERN, using data corresponding to an integrated luminosity of 20.3 fb$^{-1}$ collected by the ATLAS experiment in 2012 is presented. The fiducial cross sections for $ZZ\\to\\ell^{-}\\ell^{+}\\ell^{\\prime -}\\ell^{\\prime +}$ and $ZZ\\to \\ell^{-}\\ell^{+}\\nu\\bar{\\nu}$ are measured in selected phase-space regions. The total cross section for $ZZ$ events produced with both $Z$ bosons in the mass range 66 to 116 GeV is measured from the combination of the two channels to be $7.3\\pm0.4\\textrm{(stat)}\\pm0.3\\textrm{(syst)}\\pm0.2\\textrm{(lumi)}$ pb, which is consistent with the Standard Model prediction of $6.6^{+0.7}_{-0.6}$ pb. The differential cross sections in bins of various kinematic variables are presented. The differential event yield as a function of the transverse momentum of the leading $Z$ boson is used to set limits on anomalous neutral triple gauge boson couplings in $ZZ$ production.

Two searches for new phenomena in final states containing a same-flavour opposite-lepton (electron or muon) pair, jets, and large missing transverse momentum are presented. These searches make use of proton--proton collision data, collected during 2015 and 2016 at a centre-of-mass energy $\\sqrt{s}=13$ TeV by the ATLAS detector at the Large Hadron Collider, which correspond to an integrated luminosity of 14.7 fb$^{-1}$. Both searches target the pair production of supersymmetric particles, squarks or gluinos, which decay to final states containing a same-flavour opposite-sign lepton pair via one of two mechanisms: a leptonically decaying Z boson in the final state, leading to a peak in the dilepton invariant-mass distribution around the Z boson mass; and decays of neutralinos (e.g. $\\tilde{\\chi}_2^0 \\rightarrow \\ell^+\\ell^- \\tilde{\\chi}_1^0$), yielding a kinematic endpoint in the dilepton invariant-mass spectrum. The data are found to be consistent with the Standard Model expectation. Results are interpreted in simplified models of gluino-pair (squark-pair) production, and provide sensitivity to gluinos (squarks) with masses as large as 1.70 TeV (980 GeV).

A study of the decays B0→μ+μ− and B0s→μ+μ− has been performed using data corresponding to an integrated luminosity of 25 fb−1 of 7 TeV and 8 TeV proton--proton collisions collected with the ATLAS detector during the LHC Run 1. For B0, an upper limit on the branching fraction is set at B(B0→μ+μ−)<4.2×10−10 at 95% confidence level. For B0s, the branching fraction B(B0s→μ+μ−)=(0.9+1.1−0.8)×10−9 is measured. The results are consistent with the Standard Model expectation with a p-value of 4.8%, corresponding to 2.0 standard deviations.

The ATLAS collaboration will start to collect data at the LHC proton–proton collider in 2006. It has chosen a liquid argon-lead sampling electromagnetic calorimeter using the accordion geometry. In 1999 and 2000, barrel and end-cap prototype modules have been tested under electron beams at CERN. Detailled results from these tests are shown.

The construction of the ATLAS electromagnetic liquid argon calorimeter modules is completed and all the modules are assembled and inserted in the cryostats. During the production period four barrel and three endcap modules were exposed to test beams in order to assess their performance, ascertain the production quality and reproducibility, and to scrutinize the complete energy reconstruction chain from the readout and calibration electronics to the signal and energy reconstruction. It was also possible to check the full Monte Carlo simulation of the calorimeter. The analysis of the uniformity, resolution and extraction of constant term is presented. Typical non-uniformities of 0.5% and typical global constant terms of 0.6% are measured for the barrel and end-cap modules.

In human populations, cognitive performance in early life has been identified as a strong predictor of future dementia risk. If cognitive ability were a stable trait across the adult lifespan of mice, then this species would provide an excellent framework for understanding the biology underlying this modifiable risk factor. To address this issue, longitudinal cognitive testing was performed in female C57BL/6J mice aged between 4 and 18 months of age. By tracking individuals, we were able to demonstrate that the cognitive performance of an animal in specific tasks at 4 months of age was a remarkably reliable indicator of performance at 18 months of age. Variability in the performance of individuals was not associated with differences in macroscopic brain structure, but single‐cell recording from neurons of the prefrontal cortex did identify age‐related changes in membrane excitability. Most importantly, this study demonstrated that strategies adopted early in life to explore a nine‐arm radial maze were maintained across the adult lifespan and learning effects associated with repeated exposure to a test contribute to this stability. Overall, our results demonstrate that, like humans, cognitive ability in mice is a stable trait and the cognitive reserve necessary for healthy brain ageing is established early in life.

A full azimuthal phi-wedge of the ATLAS liquid argon end-cap calorimeter has been exposed to beams of electrons, muons and pions in the energy range 6 GeV <= E <= 200 GeV at the CERN SPS. The angular region studied corresponds to the ATLAS impact position around the pseudorapidity interval 1.6 < |eta| < 1.8. The beam test set-up is described. A detailed study of the performance is given as well as the related intercalibration constants obtained. Following the ATLAS hadronic calibration proposal, a first study of the hadron calibration using a weighting ansatz is presented. The results are compared to predictions from Monte Carlo simulations, based on GEANT 3 and GEANT 4 models.

Reliazing the pass-through effects of global commodity prices on domestic prices, this study develops a vector error correction model (VECM) to test for the determinants and direction of causality between global prices and crude palm oil (CPO) price in Thailand. Malaysian crude palm oil, world soybean oil and world crude oil prices were investigated as factors affecting the Thai CPO price. Using the Johansen cointegration test, the result unveils a presence of long-run relationship among the determinants. This long-run relationship, proposes that CPO price flows in Thailand are positively influenced by the Malaysian CPO price and the error correction term suggests that approximately 35 percent of total disequilibrium in Thai CPO price was corrected in the following month. Moreover, the findings show Granger causality from each of the Malaysian CPO price and the world soybean oil price for the Thai CPO price. Information flow regarding the price movements of the Malaysian CPO and soybean oil affect the Thai CPO price and vice-versa. Whereas, the evidence for a causal relationship that runs from the world crude oil price to the Thai CPO price is found, but not in reverse.