Searches for Weakly Interacting Supersymmetric Particles

The ATLAS and CMS collaborations have performed several targeted searches for weakly interacting supersymmetric particles, using data collected in proton-proton collisions at sqrt(s)=8 TeV at the LHC. No significant deviations from standard model predictions have been observed. These proceedings summarize some of the latest experimental results and their interpretations.Comment: 4 pages, 2 figures. Conference proceedings for the XLIXth Rencontres de Moriond, QCD and High Energy Interactions, March 22-29 2014, La Thuile, Ital

Searches for high mass dilepton resonances in pp collisions at sqrt(s) = 7 TeV with the ATLAS Experiment

The ATLAS detector has been used to search for high mass ee or mumu resonances, such as new heavy neutral gauge bosons. Over 1 fb^{-1} of proton-proton collisions at s = 7 TeV recorded by the ATLAS experiment are used to search for a high mass state decaying to dilepton pairs. No excess over Standard Model expectations is observed, and limits are placed on benchmark models predicting spin-1 and spin-2 resonances.Comment: 8 pages, 5 figures. Conference proceedings for the Meeting of the Division of Particles and Fields of the American Physical Society (DPF), 201

Editorial: The cerebellar role in psychiatric disorders: Emerging evidence and future perspectives

First paragraph: Over the past decades, clinical, neuroimaging, anatomical, and physiological studies have established the presence of a “cognitive” and a “limbic” cerebellum—the former being represented primarily in posterolateral regions and the dentate nuclei, and the latter in the vermis and the fastigial nuclei (Schmahmann et al., 2007). The “dysmetria of thought,” following damage to the cognitive cerebellum (Schmahmann, 1998) and the neuropsychiatric impairments, following damage to the limbic cerebellum (Schmahmann et al., 2007) comprise the so called “cerebellar cognitive affective syndrome” (Schmahmann and Sherman, 1998). These findings have recently renewed interest in a cerebellar pathophysiology of a broad range of neurodevelopmental and psychiatric disorders (e.g. Hoppenbrouwers et al., 2008; Lupo et al., 2019; Van Overwalle et al., 2020)

Highly Diastereoselective Multicomponent Synthesis of Spirocyclopropyl Oxindoles Enabled by Rare-Earth Metal Salts

The synthesis of polysubstituted spirocyclopropyl oxindoles using a series of rare-earth metal (REM) salts is reported. REMs, in particular Sc(OTf)3, allowed access to the target compounds by a multicomponent reaction with high diastereoselectivity (≤94:6:0:0). Density functional theory calculations on the model reaction are consistent with the observed selectivity and revealed that the special coordinating capabilities and the oxophilicity of the metal are key factors in inducing the formation of one main diastereoisomer.The authors thank Diana Cabrera, Sebastiaan van Liempd, and Juan M. Falcon-Perez from the CIC bioGUNE Metabolomics Platform for performing the UPLC-MS/MS analyses. The authors also acknowledge the Italian Ministry of University and Research (MUR) for Project SI.F.I.PA.CRO.DE. - Sviluppo e industrializzazione farmaci innovativi per terapia molecolare personalizzata PA.CRO.DE. (PON ARS01_00568, CUP: B29C20000360005) and for two doctoral grants. Moreover, the authors thank the University of Calabria and Calabria Region (PAC CALABRIA 2014–2020-Asse Prioritario 12, Azione B 10.5.12 CUP: H28D19000040006) for financial support. This research was also funded by MCIN/AEI/10.13039/501100011033 (Grant PID2021-125946OB-I00 to G.J.-O. and Severo Ochoa Excellence Accreditation CEX2021-001136-S to CIC bioGUNE)

Structural cerebellar correlates of cognitive functions in spinocerebellar ataxia type 2

Spinocerebellar ataxia type 2 (SCA2) is an autosomal dominant neurodegenerative disease involving the cerebellum and characterized by a typical motor syndrome. In addition, the presence of cognitive impairment is now widely acknowledged as a feature of SCA2. Given the extensive connections between the cerebellum and associative cerebral areas, it is reasonable to hypothesize that cerebellar neurodegeneration associated with SCA2 may impact on the cerebellar modulation of the cerebral cortex, thus resulting in functional impairment. The aim of the present study was to investigate and quantitatively map the pattern of cerebellar gray matter (GM) atrophy due to SCA2 neurodegeneration and to correlate that with patients' cognitive performances. Cerebellar GM maps were extracted and compared between SCA2 patients (n = 9) and controls (n = 33) by using voxel-based morphometry. Furthermore, the relationship between cerebellar GM atrophy and neuropsychological scores of the patients was assessed. Specific cerebellar GM regions were found to be affected in patients. Additionally, GM loss in cognitive posterior lobules (VI, Crus I, Crus II, VIIB, IX) correlated with visuospatial, verbal memory and executive tasks, while additional correlations with motor anterior (V) and posterior (VIIIA, VIIIB) lobules were found for the tasks engaging motor and planning components. Our results provide evidence that the SCA2 neurodegenerative process affects the cerebellar cortex and that MRI indices of atrophy in different cerebellar subregions may account for the specificity of cognitive symptomatology observed in patients, as result of a cerebello-cerebral dysregulation

Hunt for new phenomena using large jet multiplicities and missing transverse momentum with ATLAS in 4.7 fb−1 of s√=7TeV proton-proton collisions

Results are presented of a search for new particles decaying to large numbers of jets in association with missing transverse momentum, using 4.7 fb−1 of pp collision data at s√=7TeV collected by the ATLAS experiment at the Large Hadron Collider in 2011. The event selection requires missing transverse momentum, no isolated electrons or muons, and from ≥6 to ≥9 jets. No evidence is found for physics beyond the Standard Model. The results are interpreted in the context of a MSUGRA/CMSSM supersymmetric model, where, for large universal scalar mass m 0, gluino masses smaller than 840 GeV are excluded at the 95% confidence level, extending previously published limits. Within a simplified model containing only a gluino octet and a neutralino, gluino masses smaller than 870 GeV are similarly excluded for neutralino masses below 100 GeV

Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal

Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ γ, H → Z Z∗ →4l and H →W W∗ →lνlν. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson

Standalone vertex finding in the ATLAS muon spectrometer

A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

Measurement of the top quark-pair production cross section with ATLAS in pp collisions at \sqrt{s}=7\TeV

A measurement of the production cross-section for top quark pairs(\ttbar) in $pp$ collisions at \sqrt{s}=7 \TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two different topologies: single lepton (electron $e$ or muon $\mu$) with large missing transverse energy and at least four jets, and dilepton ($ee$, $\mu\mu$ or $e\mu$) with large missing transverse energy and at least two jets. In a data sample of 2.9 pb-1, 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding expected backgrounds from non-\ttbar Standard Model processes are estimated using data-driven methods and determined to be $12.2 \pm 3.9$ events and $2.5 \pm 0.6$ events, respectively. The kinematic properties of the selected events are consistent with SM \ttbar production. The inclusive top quark pair production cross-section is measured to be \sigmattbar=145 \pm 31 ^{+42}_{-27} pb where the first uncertainty is statistical and the second systematic. The measurement agrees with perturbative QCD calculations.Comment: 30 pages plus author list (50 pages total), 9 figures, 11 tables, CERN-PH number and final journal adde