Giovanni Petrucciani

A new event data format has been designed and prototyped by the CMS collaboration to satisfy the needs of a large fraction of physics analyses (at least 50%) with a per event size of order 1 kB. This new format is more than a factor of 20 smaller than the MINIAOD format and contains only top level information typically used in the last steps of the analysis. The talk will review the current analysis strategy from the point of view of event format in CMS (both skims and formats such as RECO, AOD, MINIAOD, NANOAOD) and will describe the design guidelines for the new NANOAOD format.

The CMS experiment has developed a new analysis object format ("Mini-AOD") targeting approximately 10% of the size of the Run 1 AOD format. The motivation for the Mini-AOD format is to have a small and quickly derived data format from which the majority of CMS analysis users can start their analysis work. This format is targeted at having sufficient information to serve about 80% of CMS analysis, while dramatically simplifying the disk and I/O resources needed for analysis. Such large reductions were achieved using a number of techniques, including defining light-weight physics-object candidate representations, increasing transverse momentum thresholds for storing physics-object candidates, and reduced numerical precision when it is not required at the analysis level. In this contribution we discuss the critical components of the Mini-AOD format, our experience with its deployment and the planned physics analysis flow for Run 2 based on the Mini-AOD.

The Phase-2 Upgrade of the CMS Level-1 Trigger (L1T) will reconstruct particles using the Particle Flow algorithm, connecting information from the tracker, muon, and calorimeter detectors, and enabling fine-grained reconstruction of high level physics objects like jets. We have developed a jet reconstruction algorithm using a cone centred on an energetic seed from these Particle Flow candidates. The implementation is designed to find up to 16 jets in each Xilinx Ultrascale+ FPGA, with a latency of less than 1 µs, and event throughput of 6.7 MHz to fit within the L1T system constraints. Pipelined processing enables reconstruction of jet collections with different cone sizes for little additional resource cost. The design of the algorithm also provides a platform for additional computation using the jet constituents, such as jet tagging using neural networks. We will describe the implementation, its jet reconstruction performance, computational metrics, and the developments towards jet tagging.

Using the likelihood ratio test statistic, we present a method which can be employed to test the hypothesis of a single Higgs boson using the matrix of measured signal strengths. This method can be applied in the presence of incomplete data and takes into account uncertainties on the measurements. The p-value against the hypothesis of a single Higgs boson is defined from the expected distribution of the test statistic, generated using pseudo-experiments. The applicability of the likelihood-based test is demonstrated using numerical examples with uncertainties and missing matrix elements.

The subsystems of the CMS silicon strip tracker were integrated and commissioned at the Tracker Integration Facility (TIF) in the period from November 2006 to July 2007. As part of the commissioning, large samples of cosmic ray data were recorded under various running conditions in the absence of a magnetic field. Cosmic rays detected by scintillation counters were used to trigger the readout of up to 15\,\% of the final silicon strip detector, and over 4.7~million events were recorded. This document describes the cosmic track reconstruction and presents results on the performance of track and hit reconstruction as from dedicated analyses.

The CMS Physics Analysis Toolkit (PAT) is presented. The PAT is a high-level analysis layer enabling the development of common analysis efforts across and within Physics Analysis Groups. It aims at fulfilling the needs of most CMS analyses, providing both ease-of-use for the beginner and flexibility for the advanced user. The main PAT concepts are described in detail and some examples from physics analyses are given.

This paper describes the top quark physics measurements that can be performed with the first LHC data in the ATLAS and CMS experiments.

The Large Hadron Collider (LHC) is a superconducting circular protonproton collider operating at the laboratories of the European Organization for Nuclear Research (CERN); it is hosted in the 27 km underground tunnel that was previously used for the Large Electron Positron Collider (LEP). The design specifications of the LHC targeted operations at a center-of-mass energy of 14 TeV, with an instantaneous luminosity of 2·1033 cm−2s−1 in the first few years and 1·1034 cm−2s−1 afterwards [16].

The Phase-2 Upgrade of the CMS Level-1 Trigger (L1T) will reconstruct particles using the Particle Flow algorithm, connecting information from the tracker, muon, and calorimeter detectors, and enabling fine-grained reconstruction of high level physics objects like jets. We have developed a jet reconstruction algorithm using a cone centred on an energetic seed from these Particle Flow candidates. The implementation is designed to find up to 16 jets in each Xilinx Ultrascale+ FPGA, with a latency of less than 1 {\mu}s, and event throughput of 6.7 MHz to fit within the L1T system constraints. Pipelined processing enables reconstruction of jet collections with different cone sizes for little additional resource cost. The design of the algorithm also provides a platform for additional computation using the jet constituents, such as jet tagging using neural networks. We will describe the implementation, its jet reconstruction performance, computational metrics, and the developments towards jet tagging.

The standard model of elementary particles and the Higgs boson.- The CMS experiment at the CERN LHC.- Searches for a Higgs boson at CMS, in the different final states.- Statistical analysis for Higgs boson searches.- Results.

The large ttbar production cross-section at the LHC suggests the use of top quark decays to calibrate several critical parts of the detectors, such as the trigger system, the jet energy scale and b-tagging.

The large ttbar production cross-section at the LHC suggests the use of top quark decays to calibrate several critical parts of the detectors, such as the trigger system, the jet energy scale and b-tagging.

Abstract NanoAOD is an event data format that has recently been commissioned by the CMS Collaboration. It only includes high level physics object information and is about 20 times more compact than the MiniAOD format. NanoAOD can be easily customised for development activities and supports automated data analysis workflows. The current status and perspectives of NanoAOD design and implementation are reviewed.

Using the likelihood ratio test statistic, we present a method which can be employed to test the hypothesis of a single Higgs boson using the matrix of measured signal strengths. This method can be applied in the presence of incomplete data and takes into account uncertainties on the measurements. The p-value against the hypothesis of a single Higgs boson is defined from the expected distribution of the test statistic, generated using pseudo-experiments. The applicability of the likelihood-based test is demonstrated using numerical examples with uncertainties and missing matrix elements.

The standard model of particle physics (SM) is a theory describing all known elementary particles and all their known interactions except for the gravitational one, which is anyway irrelevant at microscopic scales.

In the mass range from about 125 to 200GeV/c 2, a very good sensitivity to a SM Higgs boson signal at the LHC is achieved in the H → WW → 2ℓ2ν decay channel, thanks to the combination of the large branchi!ng fraction and the clean dileptonic final state with little QCD-induced background.

This book describes the searches that lead to the discovery of a Higgs boson performed at CMS, one of the two main experiments at the CERN LHC. After an overview of the theory and of the CMS experimen

The search for a Higgs boson, and more generally the investigation of the electroweak symmetry breaking, has been one of the major goals of the LHC physics program since its design phase.

In this chapter, the results of the searches for a standard model Higgs boson at CMS are presented. After an overview of the sensitivities, the results from the searches in the individual decay modes are introduced first, followed by the combined analysis of all channels together to achieve the maximal sensitivity.

The H → ZZ → 2ℓ2q decay mode has the largest branching fraction among all H→ZZ modes considered at CMS, about 20 times larger than that of the fully leptonic final state, and since all four decay products are detectable the kinematic of the event can be fully reconstructed.

The H → ggγ decay channel plays a major role in the searches for a Higgs boson in the low mass range. The branching ratio of the decay is only O(0.1%), but the diphoton final state provides a clean signature that can be exploited already at the trigger level, allowing an inclusive search to be performed. The overall strategy of the analysis is simple: a search for a narrow peak in the diphoton invariant mass spectrum over a smooth continuum background. In order to improve the performance, multivariate methods are extensively used to select events and categorize them in exclusive sets with different purity and mass resolution; an improvement of about 20% in sensitivity is achieved compared to more traditional methods used in the past [94].

The H → ZZ → 4ℓ decay mode with electrons and muons in the final state has since ever been considered the golden mode in the searches for a Higgs boson at the LHC: the requirement of four isolated leptons effectively suppresses any background process except for the irreducible continuum electroweak ZZ production, and the excellent resolution on the invariant mass of the system makes it possible to separate the signal from this background. The main limiting factors to the sensitivity in this channel are the small branching fraction of the decay and, for light Higgs bosons, the experimental challenges in reconstructing leptons of very low momentum.

Statistical inference is used to translate the outcome of the searches for a Higgs boson into statements about evidence or exclusion of a signal.

The observation of the H → bb̄ decay mode is extremely important in the context of Higgs boson searches, as it is a direct test the Yukawa couplings of the Higgs boson to quarks. Due to the overwhelming QCD multijet background in the gluon fusion and vector boson fusion production modes, the search is performed relying on associated VH production, with the vector boson decaying to leptons and/or neutrinos. In the CMS searches, five vector boson decay modes are considered: W → e ν, W → μ ν, Z → ee, Z → μ μ, and Z → ν ν, the latter is detected as a large unbalance in the transverse momentum of the event.

We present a parser to evaluate expressions and Boolean selections that is applied on CMS event data for event filtering and analysis purposes. The parser is based on Boost Spirit grammar definition, and uses Reflex dictionaries for class introspection. The parser allows for a natural definition of expressions and cuts in users' configurations, and provides good runtime performance compared to other existing parsers.

The performance of muon reconstruction in CMS has been studied on a sample of muons collected in pp collisions at ?s = 7 TeV at the LHC. Measured distributions of basic muon-track quantities are well reproduced by the Monte Carlo simulation. Efficiencies of various high-level trigger, identification, and reconstruction algorithms have been measured and compared with the expectations from Monte Carlo simulation. Results for the relative muon momentum resolution and the muon momentum scale will be reported.

Single top quark processes are interesting as direct probes of the $Wtb$ vertex, and are also an important background in searches of the Higgs boson and beyond the standard model physics. Both ATLAS and CMS have performed studies with simulated data to estimate the expected uncertainty on the production cross section measurements of the three single top processes ($t$-channel, s-channel, $tW$ production) in the first years of LHC operations. Results in the different channels and for the two experiments are reported.

This paper describes the top quark physics measurements that can be performed with the first LHC data in the ATLAS and CMS experiments.

— Single top quark processes are interesting as direct probes of the Wtb vertex, and are also an important background in searches of the Higgs boson and beyond the standard model physics. Both ATLAS and CMS have performed studies with simulated data to estimate the expected uncertainty on the production cross section measurements of the three single top processes (t-channel, s-channel, tW production) in the first years of LHC operations. Results in the different channels and for the two experiments are reported.

We review the main features of Monte Carlo generators for top quark phenomenology and present some results for t-tbar and single-top signals and backgrounds at the LHC.

We review the main features of Monte Carlo generators for top quark phenomenology and present some results for t-tbar and single-top signals and backgrounds at the LHC.

Urban planning has long been introduced into the territorial classification elements as belonging to integrated waste cycle management. Within such framework, types of urban hygiene are defined and described. In particular, the General Regulatory Plan of the City of Rome has established that areas and facilities for separate collection of waste belong to the secondary urbanization works to be identified by executive planning, as well as for temporary collection, compacting and conveying inert and bulky waste. The aim of this research is to find a shared method of selection and siting of areas compatible with the various “objects” of the integrated cycle: decentralized territorial offices, municipal collection centers, reuse centers, eco-plots, urban waste valorization plants, defined as nodes, spots, targets for a GIS based planning method. This study proposes the translation into an algorithm of operational research the needs of localization of areas to be used for infrastructure and urban hygiene, taking into account the structural and authorization factors, but also the anthropic factors. Once a sufficiently populated territorial database has been set up, thematic cartographies are developed as a decision support in the integrated cycle planning, moving away from subjective and improvised methods. From the General Regulatory Plan, the Solid Waste Urban Planning is completed so that its infrastructure can be integrated as much as possible with the urban and living needs of the citizens, reporting the operations and activities related to waste cycle within the daily metabolism of the city organism.

With the planned addition of the tracking information in the Level-1 trigger in CMS for the High-Luminosity Large Hadron Collider (HL-LHC), the algorithms for the Level-1 trigger can be completely reconceptualized. Following the example for offline reconstruction in CMS to use complementary subsystem information and mitigate pileup, we explore the feasibility of using Particle Flow-like and pileup-per-particle identification techniques at the hardware trigger level. We present the challenges of adapting these algorithm to the timing and resource constraints of the Level-1 trigger, the first prototype implementations, and the expected performance on physics object reconstruction.

Some key properties of the Higgs boson, such as its mass and couplings to electroweak bosons and third-generation fermions have by now been well established with multiple measurements by the ATLAS and CMS Collaborations.This note will instead review the status of the current "unknowns": the Higgs boson self-coupling, and Higgs boson rare and exotic decays, including those to second-generation fermions or to new light scalars.