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Information × Registration Number 0217U006064, 0116U005480 , R & D reports Title KIPT participation in the CMS data processing during Run 2 of the Large Hadron Collider and in the research work on the CMS hadron calorimetry upgrades popup.stage_title Head Levchuk Leonid Gennadievich, Кандидат фізико-математичних наук Registration Date 03-02-2017 Organization National Science Center "Kharkiv Institute of Physics and Technology popup.description2 The dataflow intensity in the CMS experiment at the Large Hadron Cpllider (LHC) in 2016 was considerably increased, with substantial hardening requirements to the distributed system of data processing. The specialized KIPT computing facility (CF) is an active participant of this system. The facility operates at Tier 2 (T2) of the hierarchical Grid-infrastructure WLCG/CMS, and its resources are exploited for physics analysis of the information accumulated in the experiment. The CF registered in the CMS as T2_UA_KIPT is the only Ukrainian T2-center of this experiment. In 2016, a further support of the T2_UA_KIPT T2-site was provided. About 1000 TB of CMS data have been transferred to the site for the year. This is more than the total amount of data transferred before. (In total, ~1.75 PB of CMS data have been transferred to T2_UA_KIPT since the LHC startup.) Despite the difficulties due to the great shortage (by factor of 3 with respect to the CMS requirements) of computing and disk resources, a high level of the CF operation quality was provided in 2016. The T2_UA_KIPT support in 2016 has been accounted for by the CMS as 7.6 FTE-months of participation in the experiment, what is a fairly good result. Also, further work on physics analysis of the CMS data has been carried on. Search for SUSY particles based on analysis of the total 2.3 fb-1 sample of events (proton-proton collisions at 13 TeV) obtained in 2015 was performed. The selected events had a registered pair of opposite-sign high transverse momentum leptons and great missing transverse energy ETmiss. Such a signature can stem from production of either slepton or chargino pair in the intermediate state. The main background processes at the event selection are top quark and weak boson pair (WW and WZ) production. In case of the same-flavor leptons ( or ee) in the final state, account for the Drell-Yan processes and Z-pair (ZZ) production is also needed. Within the achieved accuracy, the SUSY-signal of interest was not observed. To provide a quantitative estimate to the degree of agreement between the data and the standard model predictions, control event samples for all the relevant background contributions were constructed, with determining the corresponding kinematical control regions (CR). A fair agreement between the MC simulation and the data is observed for practically all the CR. An intensive study was also carried out on the radiation hardness of the SCSN-81 scintillator, which is used in the CMS hadron calorimeters. Irradiation runs were performed at the KIPT LUE-10 electron linac that provided electron beam energy of ~9.6 MeV. It was shown that placing the scintillator during irradiation into an inert atmosphere (vacuum or noble gas - argon) does not lead to any decrease of the light yield degradation degree. Furthermore, the results obtained suggest that a contact of the plastic scintillator with air (oxygen) is critically needed for recovery of its optical properties, and, practically, no relaxation occurs without such a contact. New data were obtained on the dependence of the degree of scintillator light yield degradation on the dose rate, which are in agreement with earlier measurements. Within the search for new promising radiation-resistant scintillation materials for the CMS hadron calorimetry, which could replace in future the plastic SCSN-81 scintillator, radiation properties of the YSO:Ce and YAG:Ce single-crystal scintillators and composite scintillators based on them were also studied. These scintillators have a high level of radiation hardness, and their light yield considerably exceeds the one for plastic scintillators. However, the decay time turns out to be substantially greater than that for plastic scintillators, and this can essentially restrict prospects of usage of these scintillators in the LHC experiments. Product Description popup.authors Горбенко Євген Степанович Кліменко Кім Олександрович Ковальова Людмила Семенівна Куров Олексій Олександрович Левчук Леонід Геннадійович Лук'яненко Сергій Тимофійович Попов Віктор Пилипович Приставка Олександр Сергійович Сорокін Павло Володимирович Сорока Дмитро В'ячеславович popup.nrat_date 2020-04-02 Close