R&D on the Resistive Plate Chamber for the Phase-II Upgrade of the CMS Muon Detector

The Doctoral Thesis subject has been proposed by the CMS RPC Collaboration to demonstrate that iRPC technology is the most suitable choice for the upgrade of the Muon System. The next research activities have been conducted in this context: The first activity, conducted in the framework of the iRPC RE3/1 and RE4/1 chambers integration and installation in the innermost region of CMS Muon Spectrometer, is focused on survey measurements performed in order to determine the space actually available for future installations during the Yearly Technical Stops at the end of 2022 and 2023. Surface topology and geometry of the Yoke Endcap (YE) ±2 and YE±3 iron disks in the region 1.8<|eta|<2.4 have been studied in detail by using different methods such as photography, photogrammetry, theodolite and infrared proximity sensor. After analyzing the experimental data obtained during the survey measurements, I developed the very precise 3D-model of the mechanical simulation for the installation of the RE3/1 and RE4/1 detectors in the dedicated |eta| region. I designed the mechanical components to mount chambers here. These results of my work were reported in the CMS Muon Technical Design Report (TDR) which was submitted to the CMS Muon Committee on 12 September 2017. The second activity has been focused on the developing, commissioning and characterization of the iRPC RE3/1 and RE4/1 detector prototypes. By using the information obtained during the previous activity, in August 2017 at the CERN CMS-RPC QA/QC facility, I organized the development and assembly of the first two real-size RE3/1 and RE4/1 detector prototypes and studied their detection performance with the new version of the PETIROC ASIC Front-end electronics. I was the key person who participated in all production processes on the construction and testing the detecting elements, assembling of the new prototypes and subsequent testing them with the new electronics under muon beam at the CERN Gamma Irradiation Facility (GIF++) in August 2018. By using the unique test area of the CERN GIF++ facility, I studied the iRPC detector performances at the different background conditions which will be similar to the future CMS conditions during the HL-LHC program. By studying the rate capability of the real-size iRPC detector prototypes I have experimentally shown that the new iRPC technology can effectively operate in the harsh background CMS environmental and can fulfill all physics requirements of the CMS experiment. The third my activity included the testing of the new INFN Rome Front-end electronics together with iRPC detector prototype. The INFN Rome electronics has been proposed as a possible alternative to PETIROC ASIC electronics in time for the CMS-RPC system upgrade project, thus increasing the chance of success for the project. This has been the main strategy adopted by the CMS-RPC community and, consequently, it was necessary to find another available technology in order to develop the Front-end electronics to readout the iRPC detectors. In September 2018, I developed and assembled the second real-size iRPC RE4/1 detector prototype in the INFN Rome Tor Vergata laboratories (Italy) in order to study the performance with the INFN Rome Front-end boards. As in the previous research activity, I organized the subsequent testing of the iRPC detector prototype with the new electronics in the last available muon particle beam in the GIF++ facility at CERN before the starting of the Long Shutdown -2 period at LHC. In order to compare the results obtained from the first two RE3/1 and RE4/1 detector prototypes, I have studied the same number of chamber parameters of second iRPC RE4/1 detector prototype, such as a detection efficiency, cluster size, and rate capability. I experimental shown that this type of new Front-end board can be a great substitute for the PETIROC ASIC electronics. A majority of the results obtained during the last two years of Ph.D. contributed to the success of the iRPC project and its final approval by CMS Collaboration

Distance Learning Experience in the Context of Globalization of Education

Today, the digitalization of education is one of the main tasks of the state social policy and an urgent sphere of life in modern society. At the beginning of 2020, the spread of COVID-19 forced educational institutions to introduce urgently all levels of distance learning technologies focused on the possibility to learn remotely and in real-time. The research focuses on the need to create an effective mechanism for organizing distance learning in the context of the globalization of education. The purpose of the research is to reveal the experience of distance learning in the context of globalization of education (based on the analysis of using the online learning platform Moodle). The results of the research reveal the prerequisites for the popularization of distance learning technologies in the practice of educational institutions, present the experience of using Moodle in the university educational process and determine the prospects of distance learning in educational practice

A growing concern for meaning: Exploring the links between ego development and eudaimonia

IntroductionEudaimonia, in contrast to hedonia, is theorized to be a more complex type of positive functioning that involves personal growth and is guided by the pursuit of meaning. However, the existing evidence linking eudaimonia to personality development is rather scarce. To fill this gap, we aimed to explore whether ego development is related to eudaimonic well-being and eudaimonic orientations, most notably, the concern for meaning: we explored both the quantitative differences in the presence of meaning and the search for it, as well as qualitative differences in lay theories of meaning.MethodsRussian-speaking volunteers recruited online (N = 364, aged 18 to 85, 63% female) completed measures of ego development (Washington University Sentence Completion Test), meaning in life (Meaning in Life Questionnaire), lay theories of meaning (and original 20-item measure), hedonic and eudaimonic motives for activities (HEMA), and well-being (Mental Health Continuum—Short Form).ResultsEgo development emerged as a weak, but significant positive predictor of well-being and this effect was fully mediated by the presence of meaning and eudaimonic motives. Latent profile analysis of the items tapping into lay theories of meaning revealed four distinct individual approaches to meaning that mainly differed in the subjective importance and salience of meaning. Participants with stronger concern for meaning revealed higher scores on ego development, both presence and search for meaning, eudaimonic motives, and well-being.DiscussionThe results add to the evidence concerning the links between ego development and well-being and are in line with the theoretical view of eudaimonia as a process of growth guided by personal concern for meaning. The findings suggest that eudaimonia might be more easily attained by individuals at higher stages of personal development

An embedding technique to determine ττ backgrounds in proton-proton collision data

An embedding technique is presented to estimate standard model tau tau backgrounds from data with minimal simulation input. In the data, the muons are removed from reconstructed mu mu events and replaced with simulated tau leptons with the same kinematic properties. In this way, a set of hybrid events is obtained that does not rely on simulation except for the decay of the tau leptons. The challenges in describing the underlying event or the production of associated jets in the simulation are avoided. The technique described in this paper was developed for CMS. Its validation and the inherent uncertainties are also discussed. The demonstration of the performance of the technique is based on a sample of proton-proton collisions collected by CMS in 2017 at root s = 13 TeV corresponding to an integrated luminosity of 41.5 fb(-1).Peer reviewe

Measurement of t(t)over-bar normalised multi-differential cross sections in pp collisions at root s=13 TeV, and simultaneous determination of the strong coupling strength, top quark pole mass, and parton distribution functions

Peer reviewe

Bose-Einstein correlations of charged hadrons in proton-proton collisions at s\sqrt s = 13 TeV

Bose-Einstein correlations of charged hadrons are measured over a broad multiplicity range, from a few particles up to about 250 reconstructed charged hadrons in proton-proton collisions at $\sqrt{s}$ = 13 TeV. The results are based on data collected using the CMS detector at the LHC during runs with a special low-pileup configuration. Three analysis techniques with different degrees of dependence on simulations are used to remove the non-Bose-Einstein background from the correlation functions. All three methods give consistent results. The measured lengths of homogeneity are studied as functions of particle multiplicity as well as average pair transverse momentum and mass. The results are compared with data from both CMS and ATLAS at $\sqrt{s}$ = 7 TeV, as well as with theoretical predictions.[graphic not available: see fulltext]Bose-Einstein correlations of charged hadrons are measured over a broad multiplicity range, from a few particles up to about 250 reconstructed charged hadrons in proton-proton collisions at $\sqrt{s} =$ 13 TeV. The results are based on data collected using the CMS detector at the LHC during runs with a special low-pileup configuration. Three analysis techniques with different degrees of dependence on simulations are used to remove the non-Bose-Einstein background from the correlation functions. All three methods give consistent results. The measured lengths of homogeneity are studied as functions of particle multiplicity as well as average pair transverse momentum and mass. The results are compared with data from both CMS and ATLAS at $\sqrt{s} =$ 7 TeV, as well as with theoretical predictions

Search for dark matter in events with a leptoquark and missing transverse momentum in proton-proton collisions at 13 TeV

A search is presented for dark matter in proton-proton collisions at a center-of-mass energy of root s= 13 TeV using events with at least one high transverse momentum (p(T)) muon, at least one high-p(T) jet, and large missing transverse momentum. The data were collected with the CMS detector at the CERN LHC in 2016 and 2017, and correspond to an integrated luminosity of 77.4 fb(-1). In the examined scenario, a pair of scalar leptoquarks is assumed to be produced. One leptoquark decays to a muon and a jet while the other decays to dark matter and low-p(T) standard model particles. The signature for signal events would be significant missing transverse momentum from the dark matter in conjunction with a peak at the leptoquark mass in the invariant mass distribution of the highest p(T) muon and jet. The data are observed to be consistent with the background predicted by the standard model. For the first benchmark scenario considered, dark matter masses up to 500 GeV are excluded for leptoquark masses m(LQ) approximate to 1400 GeV, and up to 300 GeV for m(LQ) approximate to 1500 GeV. For the second benchmark scenario, dark matter masses up to 600 GeV are excluded for m(LQ) approximate to 1400 GeV. (C) 2019 The Author(s). Published by Elsevier B.V.Peer reviewe

Search for an L-mu - L-tau gauge boson using Z -> 4 mu events in proton-proton collisions at root s=13 TeV

A search for a narrow Z' gauge boson with a mass between 5 and 70 GeV resulting from an L-mu - L-tau U (1) local gauge symmetry is reported. Theories that predict such a particle have been proposed as an explanation of various experimental discrepancies, including the lack of a dark matter signal in direct-detection experiments, tension in the measurement of the anomalous magnetic moment of the muon, and reports of possible lepton flavor universality violation in B meson decays. A data sample of proton-proton collisions at a center-of-mass energy of 13 TeV is used, corresponding to an integrated luminosity of 77.3 fb(-1) recorded in 2016 and 2017 by the CMS detector at the LHC. Events containing four muons with an invariant mass near the standard model Z boson mass are analyzed, and the selection is further optimized to be sensitive to the events that may contain Z -> Z'mu mu -> 4 mu decays. The event yields are consistent with the standard model predictions. Upper limits of 10(-8)-10(-7) at 95% confidence level are set on the product of branching fractions B(Z -> Z'mu mu)B(Z' -> mu mu), depending on the Z' mass, which excludes a Z' boson coupling strength to muons above 0.004-0.3. These are the first dedicated limits on L-mu - L-tau models at the LHC and result in a significant increase in the excluded model parameter space. The results of this search may also be used to constrain the coupling strength of any light Z' gauge boson to muons. (C) 2019 The Author(s). Published by Elsevier B.V.Peer reviewe

Measurement of electroweak WZ boson production and search for new physics in WZ + two jets events in pp collisions at √s=13TeV

A measurement of WZ electroweak (EW) vector boson scattering is presented. The measurement is performed in the leptonic decay modes WZ→ℓνℓ′ℓ′, where ℓ,ℓ′=e,μ. The analysis is based on a data sample of proton-proton collisions at √s=13 TeV at the LHC collected with the CMS detector and corresponding to an integrated luminosity of 35.9 fb−1. The WZ plus two jet production cross section is measured in fiducial regions with enhanced contributions from EW production and found to be consistent with standard model predictions. The EW WZ production in association with two jets is measured with an observed (expected) significance of 2.2 (2.5) standard deviations. Constraints on charged Higgs boson production and on anomalous quartic gauge couplings in terms of dimension-eight effective field theory operators are also presented