Search for supersymmetric scalar leptons at the LHC Run 2 with the ATLAS detector

Here we present an analysis of the progress on the data collected by the ATLAS detector at the LHC collider at √s = 13 TeV. The goal is to observe supersymmetric particles and, in particular, the direct pair production of scalar leptons. The scalar leptons decay into leptons and neutralinos. The final state contains two leptons, no hadronic activity and a large missing transverse momentum

Consultas neurológicas e diagnósticos em um grande hospital universitário dedicado a COVID-19

Background: More than one-third of COVID-19 patients present neurological symptomsranging from anosmia to stroke and encephalopathy. Furthermore, pre-existingneurological conditions may require special treatment and may be associated with worseoutcomes. Notwithstanding, the role of neurologists in COVID-19 is probablyunderrecognized. Objective: The aim of this study was to report the reasons forrequesting neurological consultations by internists and intensivists in a COVID-19-dedicated hospital. Methods: This retrospective study was carried out at Hospital dasClínicas da Faculdade de Medicina da Universidade de São Paulo, Brazil, a 900-bedCOVID-19 dedicated center (including 300 intensive care unit beds). COVID-19 diagnosiswas confirmed by SARS-CoV-2-RT-PCR in nasal swabs. All inpatient neurologyconsultations between March 23rd and May 23rd, 2020 were analyzed. Neurologistsperformed the neurological exam, assessed all available data to diagnose theneurological condition, and requested additional tests deemed necessary. Difficultdiagnoses were established in consensus meetings. After diagnosis, neurologists wereinvolved in the treatment. Results: Neurological consultations were requested for 89 outof 1,208 (7.4%) inpatient COVID admissions during that period. Main neurologicaldiagnoses included: encephalopathy (44.4%), stroke (16.7%), previous neurologicaldiseases (9.0%), seizures (9.0%), neuromuscular disorders (5.6%), other acute brainlesions (3.4%), and other mild nonspecific symptoms (11.2%). Conclusions: Mostneurological consultations in a COVID-19-dedicated hospital were requested for severeconditions that could have an impact on the outcome. First-line doctors should be able torecognize neurological symptoms; neurologists are important members of the medicalteam in COVID-19 hospital care.Introdução: Mais de um terço dos pacientes com COVID-19 apresentam sintomasneurológicos que variam de anosmia a AVC e encefalopatia. Além disso, doençasneurológicas prévias podem exigir tratamento especial e estar associadas a pioresdesfechos. Não obstante, o papel dos neurologistas na COVID-19 é provavelmentepouco reconhecido. Objetivo: O objetivo deste estudo foi relatar os motivos para solicitarconsultas neurológicas por clínicos e intensivistas em um hospital dedicado à COVID-19. Métodos: Estudo retrospectivo realizado no Hospital das Clínicas da Faculdade deMedicina da Universidade de São Paulo, Brasil, um centro dedicado à COVID-19 com900 leitos (incluindo 300 leitos para unidades de terapia intensiva). O diagnóstico deCOVID-19 foi confirmado por SARS-CoV-2-RT-PCR em swabs nasais. Todas asinterconsultas de neurologia hospitalar entre 23 de março e 23 de maio de 2020 foramanalisadas. Os neurologistas realizaram o exame neurológico, avaliaram todos os dadosdisponíveis para diagnosticar a patologia neurológica e solicitaram exames adicionaisconforme necessidade. Diagnósticos difíceis foram estabelecidos em reuniões deconsenso. Após o diagnóstico, os neurologistas participaram da condução dos casos.Resultados: Foram solicitadas consultas neurológicas para 89 de 1.208 (7,4%) empacientes internados por COVID-19 durante o período. Os principais diagnósticosneurológicos incluíram: encefalopatia (44,4%), acidente vascular cerebral (16,7%),doenças neurológicas prévias (9,0%), crises epilépticas (9,0%), transtornosneuromusculares (5,6%), outras lesões encefálicas agudas (3,4%) e outros sintomasleves inespecíficos (11,2%). Conclusões: A maioria das consultas neurológicas em umhospital dedicado à COVID-19 foi solicitada para condições graves que poderiam afetaro desfecho clínico. Os médicos na linha de frente devem ser capazes de reconhecersintomas neurológicos. Os neurologistas são membros importantes da equipe médica noatendimento hospitalar à COVID-19

The ABC130 barrel module prototyping programme for the ATLAS strip tracker

For the Phase-II Upgrade of the ATLAS Detector, its Inner Detector, consisting of silicon pixel, silicon strip and transition radiation sub-detectors, will be replaced with an all new 100 % silicon tracker, composed of a pixel tracker at inner radii and a strip tracker at outer radii. The future ATLAS strip tracker will include 11,000 silicon sensor modules in the central region (barrel) and 7,000 modules in the forward region (end-caps), which are foreseen to be constructed over a period of 3.5 years. The construction of each module consists of a series of assembly and quality control steps, which were engineered to be identical for all production sites. In order to develop the tooling and procedures for assembly and testing of these modules, two series of major prototyping programs were conducted: an early program using readout chips designed using a 250 nm fabrication process (ABCN-25) and a subsequent program using a follow-up chip set made using 130 nm processing (ABC130 and HCC130 chips). This second generation of readout chips was used for an extensive prototyping program that produced around 100 barrel-type modules and contributed significantly to the development of the final module layout. This paper gives an overview of the components used in ABC130 barrel modules, their assembly procedure and findings resulting from their tests.Comment: 82 pages, 66 figure

ATLAS ITk Pixel Outer Endcap CO2 cooling system prototype

In preparation for the high-luminosity LHC phase, the ATLAS detector will be upgraded with a new silicon inner tracker, the ITk, relying on a cooling system based on carbon dioxide (CO2) evaporative properties. In order to test the key aspect of the cooling, prototypes of the cooling system for the different ITk Outer Endcap layers were built in Milan and tested at the CERN CO2 BabyDEMO cooling plant. The facility is able to provide a CO2 flow of 150 g/s with a temperature as low as -45 C. The presentation will illustrate the mechanical construction of the prototype and the use of 3D-printed titanium parts. The thermal load of the detector (up to 1kW on the Layer 4 Half-Shell during normal operation) was also simulated. The sizing of the capillary present in the system, required to reach the design pressure drop 8 bar and to trigger the CO2 evaporation, will also be discussed. The pressure and temperature sensors installed in the prototype and the data acquisition will be described. The measurement performed at the BabyDEMO cooling plant, both at the nominal ATLAS operating condition and in more extreme scenarios, will be described. The systems were proved to be stable under all the conditions tested, and the total pressure drops were consistent with the requirements of the system specification

Searches for electroweak production of supersymmetric gauginos and sleptons with the ATLAS detector

Supersymmetry is one of the most motivated Standard Model extensions. Despite the meticulous search during the LHC Run I, there is no evidence supporting this theory. Starting from 2015, LHC is performing a second data taking run with a higher center of mass energy (13 TeV), providing a great occasion for the search of beyond the Standard Model physics. An important sector is the direct production of supersymmetric electroweak particles, such as sleptons and charginos. Electroweak production cross section is lower compared to strong production, but searches performed by the ATLAS and CMS experiments during LHC Run 2 excluded squark and gluinos with masses up to 2 TeV, making electroweak production an increasingly promising probe for SUSY signals at the LHC. Results obtained with the 2015-2016 ATLAS detector data will be presented. Direct production of electroweak particles like sleptons, charginos and neutralinos, with different signatures, will be considered. A good sensitivity is obtained in the signal regions and Run 1 results are largely improved

Searches for sleptons with the ATLAS detector

Many supersymmetry models feature gauginos and sleptons with masses less than a few hundred GeV. These can give rise to direct pair production rates at the LHC that can be observed in the data sample recorded by the ATLAS detector. The talk presents recent ATLAS results from searches for slepton pair production

Search for electroweak production of Supersymmetric particles at LHC Run 2 with the ATLAS detector

Supersymmetry is one of the most motivated Standard Model extensions. Despite the meticulous search during the LHC Run I, there is no evidence supporting this theory. Starting from 2015, LHC is performing a second data taking run with a higher center of mass energy (13 TeV), providing a great occasion for the search of beyond the Standard Model physics. New results obtained with the 2015-2016 ATLAS detector data will be presented. The direct production of electroweakinos, with two or three leptons in the final state and missing transverse momentum, is considered. In particular, an analysis targetting the slepton direct production with two leptons in the final state, will be illustrated. The key kinematic variables for the signal discrimination are the leptonic stransverse mass and the leptons invariant mass. A good sensitivity is obtained in the signal region for sleptons masses beyond the Run 1 limits

Search for electroweak production of supersymmetric particles at the LHC Run 2 with the ATLAS detector

Two closely related searches for the electroweak production of Supersymmetric particles are presented in this manuscript. The analyses are based on the proton-proton collision data from the Large Hadron Collider Run 2, with a center-of-mass energy of 13 TeV, collected by the ATLAS experiment. Different Supersymmetric signal models are considered. The first search targets the pair production of either the Supersymmetric partners of the leptons (sleptons) or the W boson and charged Higgs boson super-partners (charginos). In the latter case, the decay of charginos via sleptons is assumed. The search uses data collected by ATLAS between 2015 and 2016, with an integrated luminosity of 36.1 fb$^{−1}$ . The second search targets the direct production of chargino pair with W boson mediated decay. The analysis for the observation of the process was performed using the data collected by ATLAS between 2015 and 2017, reaching an integrated luminosity of 80.5 fb$^{−1}$. The signature, common to all the SUSY signal models considered, consists of two charged leptons (electrons or muons) and missing transverse energy. No significant fluctuation above the Standard Model prediction was observed in the analyses. New exclusion limits, tighter than the previously available results, were placed on the masses of the SUSY particles: slepton masses up to 500 GeV are excluded at 95% CL. Chargino masses up to 700 GeV are excluded in the case of the decay mediated by a slepton, while considering the W boson mediated decay the limit on the chargino mass is 410 GeV

Search for electroweak SUSY at ATLAS and CMS

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