L. Caminada

This Report summarizes the results of the activities of the LHC Higgs Cross Section Working Group in the period 2014-2016. The main goal of the working group was to present the state-of-the-art of Higgs physics at the LHC, integrating all new results that have appeared in the last few years. The first part compiles the most up-to-date predictions of Higgs boson production cross sections and decay branching ratios, parton distribution functions, and off-shell Higgs boson production and interference effects. The second part discusses the recent progress in Higgs effective field theory predictions, followed by the third part on pseudo-observables, simplified template cross section and fiducial cross section measurements, which give the baseline framework for Higgs boson property measurements. The fourth part deals with the beyond the Standard Model predictions of various benchmark scenarios of Minimal Supersymmetric Standard Model, extended scalar sector, Next-to-Minimal Supersymmetric Standard Model and exotic Higgs boson decays. This report follows three previous working-group reports: Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables (CERN-2011-002), Handbook of LHC Higgs Cross Sections: 2. Differential Distributions (CERN-2012-002), and Handbook of LHC Higgs Cross Sections: 3. Higgs properties (CERN-2013-004). The current report serves as the baseline reference for Higgs physics in LHC Run 2 and beyond.

We present an improved determination of the strange sea distribution in the nucleon with constraints coming from the recent charm production data in neutrino-nucleon deep-inelastic scattering by the NOMAD and CHORUS experiments and from charged current inclusive deep-inelastic scattering at HERA. We demonstrate that the results are consistent with the data from the ATLAS and the CMS experiments on the associated production of ${W}^{\ifmmode\pm\else\textpm\fi{}}$-bosons with $c$-quarks. We also discuss issues related to the recent strange sea determination by the ATLAS experiment using LHC collider data.

The FE-I4 is a new pixel readout integrated circuit designed to meet the requirements of ATLAS experiment upgrades. The first samples of the FE-I4 engineering run (called FE-I4A) delivered promising results in terms of the requested performances. The FE-I4 team envisaged a number of modifications and fine-tuning before the actual exploitation, planned within the Insertable B-Layer (IBL) of ATLAS. As the IBL schedule was pushed significantly forward, a quick and efficient plan had to be devised for the FE-I4 redesign. This article will present the main objectives of the resubmission, together with the major changes that were a driving factor for this redesign. In addition, the top-level verification and test efforts of the FE-I4 will also be addressed.

The CMS pixel barrel detector is a complex system that consists of 768 segmented silicon sensor modules. The total number of readout channels in the system is about 48 million. An overview on the module assembly and qualification procedures as well as testing results will be presented. The assembly of the detector control and readout electronics on the supply tube, the integration of the final system and the installation into CMS will be explained. The strategy and results from the early commissioning of the complete system that includes the performance of the hardware and the data acquisition and control software will be reviewed.

The FE-I4 chip for the B-layer upgrade is designed in a 130 nm CMOS process. For this design, configuration memories are based on the DICE latches where layout considerations are followed to improve the tolerance to SEU. Tests have shown that DICE latches for which layout approaches are adopted are 30 times more tolerant to SEU than the standard DICE latches. To prepare for the new pixel readout chip planned for the future upgrades, a prototype chip containing 512 pixels has been designed in a 65 nm CMOS process and a new approach is adopted for SEU tolerant latches. Results in terms of SEU and TID tolerance are presented.

This Report summarizes the results of the activities of the LHC Higgs Cross Section Working Group in the period 2014-2016. The main goal of the working group was to present the state-of-the-art of Higgs physics at the LHC, integrating all new results that have appeared in the last few years. The first part compiles the most up-to-date predictions of Higgs boson production cross sections and decay branching ratios, parton distribution functions, and off-shell Higgs boson production and interference effects. The second part discusses the recent progress in Higgs effective field theory predictions, followed by the third part on pseudo-observables, simplified template cross section and fiducial cross section measurements, which give the baseline framework for Higgs boson property measurements. The fourth part deals with the beyond the Standard Model predictions of various benchmark scenarios of Minimal Supersymmetric Standard Model, extended scalar sector, Next-to-Minimal Supersymmetric Standard Model and exotic Higgs boson decays. This report follows three previous working-group reports: Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables (CERN-2011-002), Handbook of LHC Higgs Cross Sections: 2. Differential Distributions (CERN-2012-002), and Handbook of LHC Higgs Cross Sections: 3. Higgs properties (CERN-2013-004). The current report serves as the baseline reference for Higgs physics in LHC Run 2 and beyond.

This article reviews the development of readout integrated circuits for hybrid pixel particle physics detectors. The 250-nm feature size chips in the presently operating ATLAS and CMS experiments are compared with the current state of the art in 130-nm feature size represented by the FE-I4 chip that will be used to add a new beam pipe layer for the ATLAS experiment in 2013 and the upgrade options of the CMS pixel readout chip. This includes a discussion of the array and pixel size, analog performance, readout architecture, power consumption, power distribution options and radiation hardness. Finally, recent work in 65-nm feature size as a means to continue the evolution of readout chip technology towards smaller feature size, higher rate, and lower power is presented.

In April 2021, scientists active in muon physics met to discuss and work out the physics case for the new High-Intensity Muon Beams (HIMB) project at PSI that could deliver of order $10^{10}$\,s$^{-1}$ surface muons to experiments. Ideas and concrete proposals were further substantiated over the following months and assembled in the present document. The high intensities will allow for completely new experiments with considerable discovery potential and unique sensitivities. The physics case is outstanding and extremely rich, ranging from fundamental particle physics via chemistry to condensed matter research and applications in energy research and elemental analysis. In all these fields, HIMB will ensure that the facilities S$\mu$S and CHRISP on PSI's High Intensity Proton Accelerator complex HIPA remain world-leading, despite the competition of muon facilities elsewhere.

MoTiC (Monolithic Timing Chip) is a prototype DMAPS Chip that builds on sensor technology developed in the ARCADIA project.The 50 by 50 µm 2 pixels contain a small charge collecting electrode with a very low capacitance surrounded by radiation-hard in-pixel electronics.The chip contains a matrix of 5120 pixels on an area of 3.2 by 4 mm 2 .Each pixel features a trimmable and maskable comparator with a sample and hold circuit for the analog pulse height.Groups of 4 pixels share a TDC situated also in the readout matrix.This work presents the chip design and preliminary results of the hit efficiencies and spatial resolution measured in a first test beam campaign with 4-5 GeV/c electrons conducted at DESY.

To make the best possible use of the higher luminosity provided by the upgraded HERA collider, the H1 collaboration has built the Fast Track Trigger (FTT). It is integrated in the first three levels (L1-L3) of the H1 trigger scheme and provides enhanced selectivity for events with charged particles. The FTT allows the reconstruction of tracks in the central drift chambers down to 100 MeV. Within the 2.3 mus latency of the first trigger level coarse two dimensional track information in the plane transverse to the beam is provided. At the second trigger level (20 mus latency), high resolution, three dimensional tracks are reconstructed. Trigger decisions are derived from track momenta, multiplicities and topologies. At the third trigger level a farm of commercial PowerPC boards allows a partial event reconstruction. Within the L3 latency of 100 mus exclusive final states (e.g. D*,J/psi) are identified using track based invariant mass calculations. In addition an on-line particle identification of electrons and muons with additional information from other subdetectors is performed. First results obtained from the third level, which is fully operational since 2006, are presented.

The ATLAS FE-I4 ASIC is a novel pixel detector readout chip designed in a CMOS 130 nm feature size process.The chip is able to cope with high hit rate and withstand the harsh radiation environment in close proximity to the interaction point at LHC. FE-I4 will find its first application with ATLAS IBL, an additional innermost pixel layer scheduled for installation in 2013, but is also suited for the intermediate radii pixel layers for future upgrades.In this paper, the modular design concept of FE-I4 is introduced and its readout architecture, analog performance and radiation hardness are discussed.After the successful development of the first full-scale prototype version of the chip in 2010, the production version for IBL (FE-I4B) has recently become available.Here, we review the main design choices for FE-I4B and present first testing results.

We consider the impact of the recent data obtained by the LHC, Tevatron, and fixed-target experiments on the nucleon quark distributions with a particular focus on disentangling different quark species. An improved determination of the poorly known strange sea distribution is obtained due to including data from the neutrino-induced deep-inelastic scattering experiments NOMAD and CHORUS. The impact of the associated (W + c) production data by CMS and ATLAS on the strange sea determination is also studied and a comparison with earlier results based on the collider data is discussed. Finally, the recent LHC and Tevatron data on the charged lepton asymmetry are compared to the NNLO ABM predictions and the potential of this input in improving the non-strange sea distributions is evaluated.

In this diploma thesis the development of a trigger for the semileptonic decay of b-quarks into electrons is presented. The trigger is implemented on the third trigger level (L3) of the H1 detector at HERA and uses the information of the Fast Track Trigger (FTT) and the new calorimeter trigger, the Jet Trigger. The potential of different L3 electron trigger setups is studied by calculating the efficiency in simulated data and estimating the rejection power in photoproduction events. A proposal for a future trigger strategy is derived that provides the running of a single electron trigger (with a momentum acceptance down to 2 GeV) complemented for lower momenta (> 1 GeV) by a double electron trigger. The trigger efficiency reaches ∼60%, whilst L3 output rates of 1-2 Hz are possible.

We consider the impact of the recent data obtained by the LHC, Tevatron, and fixed-target experiments on the nucleon quark distributions with a particular focus on disentangling different quark species. An improved determination of the poorly known strange sea distribution is obtained due to including data from the neutrino-induced deep-inelastic scattering experiments NOMAD and CHORUS. The impact of the associated (W + c) production data by CMS and ATLAS on the strange sea determination is also studied and a comparison with earlier results based on the collider data is discussed. Finally, the recent LHC and Tevatron data on the charged lepton asymmetry are compared to the NNLO ABM predictions and the potential of this input in improving the non-strange sea distributions is evaluated.

This thesis describes one of the first measurements made at CERN’s Large Hadron Collider, the world's largest and highest-energy particle collider. The method of analysis described in the first part i

The Large Hadron Collider (LHC) is designed to collide proton beams at a center-of-mass energy of $$\sqrt{s}=14\,\rm {TeV}\ $$ and a nominal instantaneous luminosity of $$\mathcal{L} \ =10^{34}\,\rm {cm^{-2}s^{-1}}$$ . This represents a seven-fold increase in energy and a hundred-fold increase in integrated luminosity over the previous hadron collider experiments. The beam energy and the design luminosity have been chosen in order to study physics at the TeV energy scale. The main motivation of the LHC is to reveal the nature of electroweak symmetry breaking and to investigate potential manifestations of new physics phenomena beyond the SM.

The CMS pixel detector allows for high precision tracking in the region closest to the interaction point in a particularly harsh environment characterized by a high track multiplicity and heavy irradiation. The main purpose of the pixel detector is the reconstruction of secondary vertices from heavy flavor and tau decays and the generation of track seeds for track reconstruction.

The prospects for a measurement of the inclusive b-quark production cross-section with the very early data at CMS are presented in this chapter. Due to the large b-quark production cross-section, high statistics data samples are expected soon after the LHC start-up. Measurements of the b-quark production have already been done at the Tevatron, HERA and other colliders. A lot of progress has been made in understanding the b-quark production process and the measurements are in reasonable agreement with NLO/NLL QCD predictions in most regions of the phase space.

The production of jets in association with a W or Z boson in proton-proton collisions at √s = 7 TeV is measured with the ATLAS detector at the LHC. The cross sections, differential in several kinematic variables, have been measured up to high jet multiplicities and are compared to new higher-order QCD calculations. Measurements of vector bosons in association with heavy flavor, such as W+c and W+b production, have unique sensitivity to the heavy quark density of the proton. Differential cross sections are presented and compared to QCD predictions at NLO.

The CMS BPIX detector system was assembled and fully tested at PSI before it was transported to CERN [1]. A slice of the CMS control and data acquisition system has been setup at PSI in order to have a tool for operating and testing larger segments of the pixel detector.

The study of heavy quark production is an important research area at the LHC. Heavy quarks will be produced with a large cross section at a yet unreached center-of-mass energy, enabling precision measurements to improve our understanding of heavy flavor physics. In the context of this work the term heavy quark stands for charm and beauty quarks since the mass of the up, down and strange quark are significantly lower. The heavier top quark has a very short lifetime and does therefore not form bound states of heavy hadrons.

The understanding of the matter that surrounds us has been intriguing scientists and philosophers ever since. The idea that all matter is composed of fundamental building blocks was first conceived of by Greek philosophers more than two thousand years ago. This idea remained untested until the early twentieth century when the first experiments investigating the subatomic structures were performed. A tremendous technological progress in the second half of the century allowed to develop new experimental methods and revolutionized the field of particle physics. The construction of large scale particle accelerators and ever more sophisticated detectors paved the way to a host of discoveries. Based on these experiments a new level of understanding has been gained. Nearly everything we currently know about the constituents of matter and their interactions can be described by a relativistic quantum field theory known as the Standard Model (SM) of elementary particle physics.

A study of the inclusive b-quark production at the CMS experiment has been presented within this work. Thanks to the large b-quark production cross section at the LHC, high statistics data samples are available soon after the LHC startup. The measurement of the b-quark production cross section with these data is therefore a prime candidate to yield one of the first physics result obtained from proton-proton collisions at a center-of-mass energy of $$\sqrt{s}=7$$ TeV.

In December 2009 proton-proton collisions at the LHC were recorded with the CMS detector for the first time. The collisions happened at a center-of-mass energy of \(\sqrt{s}=900\) GeV and \(\sqrt{s}=2.36\) TeV. The data collected during the first LHC running period were used in this work to study the performance of the physics object reconstruction and to compare it to the results of the MC simulation.

On March 30, 2010, the first proton-proton collisions at a center-of-mass energy of $$\sqrt{s}=7$$ TeV happened at the LHC. The data statistics recorded by the CMS detector during the first months of data-taking allows for a first measurement of the inclusive $$b$$ -quark production cross-section at the LHC. The preliminary result has been presented at the 35th International Conference on High Energy Physics.

A search is presented for narrow resonances decaying to dijet final states in proton–proton collisions at s√=13TeV using data corresponding to an integrated luminosity of 12.9 $fb{−1}$. The dijet mass spectrum is well described by a smooth parameterization and no significant evidence for the production of new particles is observed. Upper limits at 95% confidence level are reported on the production cross section for narrow resonances with masses above 0.6 TeV. In the context of specific models, the limits exclude string resonances with masses below 7.4 TeV, scalar diquarks below 6.9 TeV, axigluons and colorons below 5.5 TeV, excited quarks below 5.4 TeV, color-octet scalars below 3.0 TeV, W′ bosons below 2.7 TeV, Z′ bosons below 2.1 TeV and between 2.3 and 2.6 TeV, and RS gravitons below 1.9 TeV. These extend previous limits in the dijet channel. Vector and axial-vector mediators in a simplified model of interactions between quarks and dark matter are excluded below 2.0 TeV. The first limits in the dijet channel on dark matter mediators are presented as functions of dark matter mass and are compared to the exclusions of dark matter in direct detection experiments.

We present a readout chip prototype for future pixel detectors with timing capabilities. The prototype is intended for characterizing 4D pixel arrays with a pixel size of $100\times100~\mu \text{m}^2$, where the sensors are Low Gain Avalanche Diodes (LGADs). The long-term focus is towards a possible replacement of disks in the extended forward pixel system (TEPX) of the CMS experiment during the High Luminosity LHC (HL-LHC). The requirements for this ASIC are the incorporation of a Time to Digital Converter (TDC) within each pixel, low power consumption, and radiation tolerance up to $5\times10^{15}~n_\text{eq}\text{~cm}^{-2}$ to withstand the radiation levels in the innermost detector modules for $3000 \text{fb}^{-1}$ of the HL-LHC (in the TEPX). A prototype has been designed and produced in 110~nm CMOS technology at LFoundry and UMC with different versions of TDC structures, together with a front end circuitry to interface with the sensors. The design of the TDC will be discussed, with the test set-up for the measurements, and the first results comparing the performance of the different structures.

The silicon pixel detector of the CMS experiment at the LHC provides high precision tracking in the region closest to the proton–proton collision point. It operates in a particularly harsh environment characterized by high track multiplicity and heavy irradiation which poses severe challenges to the detector design. At the beginning of 2017, the original pixel detector was replaced with an upgraded 4-layer pixel system to maintain the excellent tracking performance of CMS in view of the increasing luminosity scenario (up to 2.5×1034 cm−2s−1 during Run 2 and 3). The CMS Phase 1 detector features a new readout chip to reduce the dynamic inefficiency at high rate as well as an additional innermost layer at a radius of 3 cm from the interaction point to improve the impact parameter resolution. This paper reviews the main design features of the CMS Phase 1 pixel detector and discuss its performance and the challenges in operation during the first year of data-taking in 2017. Furthermore, the paper reports about the consolidation work performed during the LHC year end technical stop and the status of the Phase 1 pixel detector and re-commissioning toward operation in 2018.

The cross sections for the production of $t\overline{t}b\overline{b}$ and $t\overline{t}jj$ events and their ratio $\sigma_{t\overline{t}b\overline{b}} / \sigma_{t\overline{t}jj}$ are measured using data corresponding to an integrated luminosity of 2.3 $fb^{−1}$collected in pp collisions at $\sqrt{s}$ = 13TeV with the CMS detector at the LHC. Events with two leptons (e or μ) and at least four reconstructed jets, including at least two identified as b quark jets, in the final state are selected. In the full phase space, the measured ratio is $0.022 \pm 0.003(stat) \pm 0.006(syst)$, the cross section $\sigma_{t\overline{t}b\overline{b}}$ is $4.0 \pm 0.6(stat) \pm 1.3(syst)pb$ and $\sigma_{t\overline{t}jj}$ is $184 \pm 6(stat) \pm 33(syst)pb$. The measurements are compared with the standard model expectations obtained from a powheg simulation at next-to-leading-order interfaced with pythia.