Toni Šćulac

SKIROC2_CMS is a chip derived from CALICE SKIROC2 that provides 64 channels of low noise charge preamplifiers optimized for 50 pF pin diodes and 10 pC dynamic range. They are followed by high gain and low gain 25 ns shapers, a 13-deep 40 MHz analog memory used as a waveform sampler at 40 MHz. and 12-bit ADCs. A fast shaper followed by discriminator and TDC provide timing information to an accuracy of 50 ps, in order to test TOT and TOA techniques at system level and in test-beam. The chip was sent to fabrication in January 2016 in AMS SiGe 0,35 μm and was received in May. It was tested in the lab during the summer and will be mounted on sensors for beam-tests in the fall.

Aim: To develop a simple algorithm that accurately constructs and simulates an Alvarez-type linear accelerator given the initial conditions and number of accelerator parts. Methods: We wrote the algorithm in Python, a programming language with numerous useful math and science libraries, and the ability to use classes and objects. The particles were accelerated in electric fields (which we assumed to be constant within each cavity at any given moment) to allow for a comparison of numerical results with an analytic expression. No magnetic fields were present in the simulations used in this article, and the particle beams were instead focused by using collimators. The algorithm first constructed the accelerator by guessing the appropriate length of each segment until it found optimal lengths for accelerating most particles in the beam. Once constructed, the accelerator could accelerate beams of particles and the results could be analyzed. Results: The algorithm successfully constructed multiple different accelerators from the initially given conditions. The first two simulations had arbitrary accelerators in which hydrogen and lead ions were accelerated, and the results were in line with expectations from the analytic solution. The largest simulation was that of CERN’s Linac4 accelerator, which produced results similar to those found in the real world. Conclusion: Significant results could be obtained even with an algorithm as simple as the one described here. The algorithm could be further improved by using a more realistic potential inside the accelerator cavities, and more particles could pass through if magnetic fields which focus the beam were turned on

Jet production occurs very often in particle physics experiments, and a very good understanding of how partons evolve into jets has been achieved over the last 30 years. The main tool in jet analysis is jet clustering algorithms, and because the problem of clustering particles back to initial partons can not be solved exactly, many different algorithms have been developed. In this work, we propose a new dipole-based jet clustering algorithm, called the dipole-$k_t$ algorithm with two main features; it uses a Lorentz invariant distance measure, and it does 3 to 2 recombinations in an attempt to invert a dipole-based parton shower. We validate its exclusive version by comparing it to the k_t-algorithm. We then proceed to analyze the dipole-k_t results in W-production events in proton proton collisions, where the has a large transverse momentum and decays into jets. A simple analysis of the W mass reconstruction strengthens our hope that with future developments this area of work will become dipole-k_t algorithm's main forte.

This document includes a data set from a survey of research fields, groups, and situations where remote work is already practised which is used for Remote work and remotization of infrastructure case study.

This document includes a data set from a survey of research fields, groups, and situations where remote work is already practised which is used for Remote work and remotization of infrastructure case study.

Properties of the Higgs boson are measured in the H → ZZ → 4 ( = e, µ) decay channel.A data sample of proton-proton collisions at a center-of-mass energy of 13 TeV is used, corresponding to an integrated luminosity of 41.5 fb -1 recorded in 2017 by the CMS detector at the LHC.The signal-strength modifier µ, defined as the ratio of the observed Higgs boson rate in the H → ZZ → 4 decay channel to the standard model expectation, is measured to be µ = 1.10 +0.19 -0.

This thesis presents the measurements of Higgs (H) boson properties in the four-lepton decay channel in proton-proton collisions at a centre-of-mass e

A search for resonance like structures in the B0sπ± invariant mass spectrum is performed using proton-proton collision data collected by the CMS experiment at the LHC at √s=8 TeV, corresponding to an integrated luminosity of 19.7 fb−1. The B0s mesons are reconstructed in the decay chain B0s→J/ψϕ, with J/ψ→μ+μ− and ϕ→K+K−. The B0sπ± invariant mass distribution shows no statistically significant peaks for different selection requirements on the reconstructed B0s and π± candidates. Upper limits are set on the relative production rates of the X(5568) and B0s states times the branching fraction of the decay X(5568)±→B0sπ±. In addition, upper limits are obtained as a function of the mass and the natural width of possible exotic states decaying into B0sπ±.

Differential Higgs boson production cross sections are sensitive probes for physics beyond the Standard Model.New physics may contribute in the gluon-gluon fusion loop, the dominant Higgs boson production mechanism at the LHC, and manifest itself through deviations from the distributions predicted by the standard model.A variety of measurements are reported using the H → γγ, H → ZZ * → 4 , and their combinations together with boosted H → b b from ATLAS and CMS Collaborations.No significant deviations from the Standard Model expectations are observed.Precision on measurements is still largely statistically limited.Finally, projections of the differential cross section measurements for the High-Luminosity LHC are reported assuming different scenarios in the extrapolation of systematical uncertainties.

Les mesures des proprietes du boson de Higgs dans le canal en 4 leptons sont rapportees dans cette these. Les donnees prises avec le detecteur CMS dans des collisions proton-proton a 13 TeV dans le centre de masse sont utilisees. Des ameliorations importantes, touchant plusieurs aspects de l'analyse, ont ete apportees. Mes contributions principales portent sur deux grands axes: amelioration de la mesure d'efficacite de selection des electrons et analyse des donnees 2017 en tant qu'analyseur et editeur principal.Les resultats sont montrees pour les donnees du Run II, collectees en 2016 et 2017, correspondant a des luminosites integrees de 35.9 fb-1 et 41.5 fb-1, respectivement.Les modifications de l'intensite de signal, relative aux predictions du Modele Standard (MS), la masse et la largeur du boson de Higgs ainsi que les sections efficaces de production inclusives et differentielles sont mesurees. Tous les resultats sont en bon accord avec les predictions du MS pour un boson de Higgs avec une masse de 125 GeV.Finalement, une mesure des modificateurs de l'intensite du signal est effectuee en combinant les donnees 2016 et 2017, pour un total de 77 fb-1. Une nouvelle fois, ces mesures sont en accord avec le MS. De nouvelles frontieres sont desormais atteintes, les incertitudes statistiques et systematiques sont desormais d'egale contribution a l'incertitude totale sur les mesures inclusives de section efficace de production.