Massimo Lazzaroni

Massimo Lazzaroni
University of Milan | UNIMI · Department of Physics

PhD in Electrical Engineering

About

474
Publications
335,341
Reads
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17,561
Citations
Introduction
Measurement and Intrumentation for High Energy Physics. Design of electronic equipment for ATLAS Experiment at CERN. Quality. Dependability.
Additional affiliations
January 2014 - present
CERN
Position
  • Engineer
Description
  • Member of ATLAS Collaboration. Author of ATLAS Collaboration (since 11/2015) Memebr of LAr Group.
January 2013 - present
INFN - Istituto Nazionale di Fisica Nucleare
Position
  • Professor (Associate)
Description
  • Associated with assignment of Scientific Research

Publications

Publications (474)
Article
Full-text available
Searches for new resonances in the diphoton final state, with spin 0 as predicted by theories with an extended Higgs sector and with spin 2 using a warped extra-dimension benchmark model, are presented using 139 fb⁻¹ of s=13 TeV pp collision data collected by the ATLAS experiment at the LHC. No significant deviation from the Standard Model is obser...
Article
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A search for pair production of bottom squarks in events with hadronically decaying τ-leptons, b-tagged jets, and large missing transverse momentum is presented. The analyzed dataset is based on proton-proton collisions at s=13 TeV delivered by the Large Hadron Collider and recorded by the ATLAS detector from 2015 to 2018, and corresponds to an int...
Article
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Exclusive dimuon production in ultraperipheral collisions (UPC), resulting from photon-photon interactions in the strong electromagnetic fields of colliding high-energy lead nuclei, PbPb(γγ)→μ+μ−(Pb(★)Pb(★)), is studied using Lint=0.48nb−1 of sNN=5.02TeV lead-lead collision data at the LHC with the ATLAS detector. Dimuon pairs are measured in the f...
Article
Jet energy scale and resolution measurements with their associated uncertainties are reported for jets using 36–81 fb-1 of proton–proton collision data with a centre-of-mass energy of s=13 TeV collected by the ATLAS detector at the LHC. Jets are reconstructed using two different input types: topo-clusters formed from energy deposits in calorimeter...
Article
Measurements of both the inclusive and differential production cross sections of a top-quark–antiquark pair in association with a Z boson (tt¯Z) are presented. The measurements are performed by targeting final states with three or four isolated leptons (electrons or muons) and are based on s=13 TeV proton–proton collision data with an integrated lu...
Article
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A search for charged leptons with large impact parameters using 139 fb−1 of s=13 TeV pp collision data from the ATLAS detector at the LHC is presented, addressing a long-standing gap in coverage of possible new physics signatures. Results are consistent with the background prediction. This search provides unique sensitivity to long-lived scalar sup...
Article
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A search for long-lived particles, which have come to rest within the ATLAS detector, is presented. The subsequent decays of these particles can produce high-momentum jets, resulting in large out-of-time energy deposits in the ATLAS calorimeters. These de- cays are detected using data collected during periods in the LHC bunch structure when collisi...
Article
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Two-particle long-range azimuthal correlations are measured in photonuclear collisions using 1.7nb−1 of 5.02 TeV Pb+Pb collision data collected by the ATLAS experiment at the CERN Large Hadron Collider. Candidate events are selected using a dedicated high-multiplicity photonuclear event trigger, a combination of information from the zero-degree cal...
Article
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Leptons with essentially the same properties apart from their mass are grouped into three families (or flavours). The number of leptons of each flavour is conserved in interactions, but this is not imposed by fundamental principles. Since the formulation of the standard model of particle physics, the observation of flavour oscillations among neutri...
Article
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The standard model of particle physics encapsulates our best current understanding of physics at the smallest scales. A fundamental axiom of this theory is the universality of the couplings of the different generations of leptons to the electroweak gauge bosons. The measurement of the ratio of the decay rate of W bosons to τ leptons and muons, R(τ/...
Article
This article presents a new set of proton parton distribution functions, ATLASepWZVjet20, produced in an analysis at next-to-next-to-leading order in QCD. The new data sets considered are the measurements of W+ and W− boson and Z boson production in association with jets in pp collisions at s = 8 TeV performed by the ATLAS experiment at the LHC wit...
Article
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Fiducial and differential cross-section measurements of W+W− production in association with at least one hadronic jet are presented. These measurements are sensitive to the properties of electroweak-boson self-interactions and provide a test of perturbative quantum chromodynamics and the electroweak theory. The analysis is performed using proton-pr...
Preprint
Full-text available
The capture of scintillation light emitted by liquid Argon and Xenon under molecular excitations by charged particles is still a challenging task. Here we present a first attempt to design a device able to grab sufficiently high luminosity in order to reconstruct the path of ionizing particles. This preliminary study is based on the use of masks to...
Conference Paper
Within the framework of the DUNE experiment, the X-ARAPUCA detector is the chosen solution for the collection of Liquid Argon scintillation light, generated by the passage of charged particles. The X-ARAPUCA design exploits Silicon PhotoMultipliers (SiPM) that are spread over a wide area, and therefore require innovative solutions for ganging and s...
Article
Full-text available
A search for the Higgs boson decaying into a photon and a pair of electrons or muons with an invariant mass mℓℓ<30 GeV is presented. The analysis is performed using 139 fb⁻¹ of proton–proton collision data, produced by the LHC at a centre-of-mass energy of 13 TeV and collected by the ATLAS experiment. Evidence for the H→ℓℓγ process is found with a...
Article
The production cross-section of a top quark in association with a W boson is measured using proton–proton collisions at \sqrt{s} = 8\,\text {TeV}. The dataset corresponds to an integrated luminosity of 20.2\,\text {fb}^{-1}, and was collected in 2012 by the ATLAS detector at the Large Hadron Collider at CERN. The analysis is performed in the single...
Article
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A search for long-lived particles decaying into hadrons and at least one muon is presented. The analysis selects events that pass a muon or missing-transverse-momentum trigger and contain a displaced muon track and a displaced vertex. The analyzed dataset of proton-proton collisions at s=13 TeV was collected with the ATLAS detector and corresponds...
Article
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A search for heavy neutral Higgs bosons produced in association with one or two b-quarks and decaying to b-quark pairs is presented using 27.8 fb−1 of s=13 TeV proton-proton collision data recorded by the ATLAS detector at the Large Hadron Collider during 2015 and 2016. No evidence of a signal is found. Upper limits on the heavy neutral Higgs boson...
Article
Full-text available
A search for heavy neutral Higgs bosons produced in association with one or two b -quarks and decaying to b -quark pairs is presented using 27.8 fb − 1 of √ s = 13 TeV proton-proton collision data recorded by the ATLAS detector at the Large Hadron Collider during 2015 and 2016. No evidence of a signal is found. Upper limits on the heavy neutral Hig...
Article
Full-text available
A study of the charge conjugation and parity (CP) properties of the interaction between the Higgs boson and top quarks is presented. Higgs bosons are identified via the diphoton decay channel (H→γγ), and their production in association with a top quark pair (tt¯H) or single top quark (tH) is studied. The analysis uses 139 fb−1 of proton–proton coll...
Article
Full-text available
The results of a search for electroweakino pair production \(pp \rightarrow \tilde{\chi }^\pm _1 \tilde{\chi }^0_2\) in which the chargino (\(\tilde{\chi }^\pm _1\)) decays into a W boson and the lightest neutralino (\(\tilde{\chi }^0_1\)), while the heavier neutralino (\(\tilde{\chi }^0_2\)) decays into the Standard Model 125 GeV Higgs boson and a...
Article
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A search for direct pair production of scalar partners of the top quark (top squarks or scalar third-generation up-type leptoquarks) in the all-hadronic \(t{\bar{t}}\) plus missing transverse momentum final state is presented. The analysis of 139 \(\hbox {fb}^{-1}\) of \({\sqrt{s}=13}\) TeV proton–proton collision data collected using the ATLAS det...
Article
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A measurement of observables sensitive to spin correlations in \(t\bar{t}\) production is presented, using 36.1 \(\hbox {fb}^{-1}\) of pp collision data at \(\sqrt{s} = 13\) TeV recorded with the ATLAS detector at the Large Hadron Collider. Differential cross-sections are measured in events with exactly one electron and one muon with opposite-sign...
Article
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A bstract The factor of four increase in the LHC luminosity, from 0 . 5 × 10 ³⁴ cm − 2 s − 1 to 2 . 0 × 10 ³⁴ cm − 2 s − 1 , and the corresponding increase in pile-up collisions during the 2015–2018 data-taking period, presented a challenge for the ATLAS trigger, particularly for those algorithms that select events with missing transverse momentum....
Article
Full-text available
A search for heavy neutral Higgs bosons is performed using the LHC Run 2 data, corresponding to an integrated luminosity of 139 fb−1 of proton-proton collisions at s=13 TeV recorded with the ATLAS detector. The search for heavy resonances is performed over the mass range 0.2–2.5 TeV for the τ+τ− decay with at least one τ-lepton decaying into final...
Article
Full-text available
In industrial applications, among several varieties of semiconductor devices available, a silicon-controlled rectifier (SCR) is often used in managing and protecting various systems with different applications. Hence, it is of the utmost importance to design a control system which can operate over a range of electrical loads without any modificatio...
Article
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A bstract Single top-quark production in association with a Z boson, where the Z boson decays to a pair of charged leptons, is measured in the trilepton channel. The proton-proton collision data collected by the ATLAS experiment from 2015 to 2018 at a centre-of-mass energy of 13 TeV are used, corresponding to an integrated luminosity of 139 fb − 1...
Article
A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of √ s = 13 TeV were collected between 2015 and 2018 by the ATLAS e...
Article
Jet substructure quantities are measured using jets groomed with the soft-drop grooming procedure in dijet events from 32.9 fb − 1 of p p collisions collected with the ATLAS detector at √ s = 13 TeV . These observables are sensitive to a wide range of QCD phenomena. Some observables, such as the jet mass and opening angle between the two subjets wh...
Article
A search is presented for pair production of long-lived neutral particles using 33 fb − 1 of √ s = 13 TeV proton–proton collision data, collected during 2016 by the ATLAS detector at the LHC. This search focuses on a topology in which one long-lived particle decays in the ATLAS inner detector and the other decays in the muon spectrometer. Special t...
Article
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A search for a heavy charged-boson resonance decaying into a charged lepton (electron or muon) and a neutrino is reported. A data sample of 139 fb−1 of proton-proton collisions at s=13 TeV collected with the ATLAS detector at the LHC during 2015–2018 is used in the search. The observed transverse mass distribution computed from the lepton and missi...
Article
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This paper presents a measurement of quantities related to the formation of jets from high-energy quarks and gluons (fragmentation). Jets with transverse momentum 100 GeV <pT<2.5 TeV and pseudorapidity |η|<2.1 from an integrated luminosity of 33 fb−1 of s=13 TeV proton-proton collisions are reconstructed with the ATLAS detector at the Large Hadron...
Article
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This paper presents a measurement of forward-forward and forward-central dijet azimuthal angular correlations and conditional yields in proton-proton (pp) and proton-lead (p+Pb) collisions as a probe of the nuclear gluon density in regions where the fraction of the average momentum per nucleon carried by the parton entering the hard scattering is l...
Article
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A search for the production of three massive vector bosons in proton–proton collisions is performed using data at √s = 13 TeV recorded with the ATLAS detector at the Large Hadron Collider in the years 2015–2017, corresponding to an integrated luminosity of 79.8 fb−1. Events with two same-sign leptons (electrons or muons) and at least two reconstruc...
Article
Full-text available
Searches for scalar leptoquarks pair-produced in proton–proton collisions at \(\sqrt{s}=13\) TeV at the Large Hadron Collider are performed by the ATLAS experiment. A data set corresponding to an integrated luminosity of 36.1 fb\(^{-1}\) is used. Final states containing two electrons or two muons and two or more jets are studied, as are states with...
Article
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A search for a right-handed gauge boson WR, decaying into a boosted right-handed heavy neutrino NR, in the framework of Left-Right Symmetric Models is presented. It is based on data from proton–proton collisions with a centre-of-mass energy of 13 TeV collected by the ATLAS detector at the Large Hadron Collider during the years 2015, 2016 and 2017,...
Article
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A measurement of the Higgs boson production cross sections via associated WH and ZH production using H→WW⁎→ℓνℓν decays, where ℓ stands for either an electron or a muon, is presented. Results for combined WH and ZH production are also presented. The analysis uses events produced in proton–proton collisions collected with the ATLAS detector at the La...
Article
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This paper presents measurements of the \(W^+ \rightarrow \mu ^+\nu \) and \(W^- \rightarrow \mu ^-\nu \) cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton–proton collisions at a centre-of-mass energy of 8 \(\text {TeV}\) with the ATLAS experiment at...
Article
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A bstract Narrow resonances decaying into W W , W Z or ZZ boson pairs are searched for in 139 fb − 1 of proton-proton collision data at a centre-of-mass energy of $$ \sqrt{s} $$ s = 13 TeV recorded with the ATLAS detector at the Large Hadron Collider from 2015 to 2018. The diboson system is reconstructed using pairs of high transverse momentum, lar...
Article
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The inclusive production rates of isolated, prompt photons in p+Pb collisions at sNN=8.16 TeV are studied with the ATLAS detector at the Large Hadron Collider using a dataset with an integrated luminosity of 165 nb−1 recorded in 2016. The cross-section and nuclear modification factor RpPb are measured as a function of photon transverse energy from...
Article
The Phase-I upgrade of the trigger readout electronics for the ATLAS Liquid Argon (LAr) calorimeters will be installed during the second long shutdown of the Large Hadron Collider (LHC) in 2019-2020 which will enable enhanced instantaneous luminosities during LHC Run 3 from 2021 through 2023. In this trigger upgrade, so-called supercells are introd...
Article
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Dark matter particles, if sufficiently light, may be produced in decays of the Higgs boson. This Letter presents a statistical combination of searches for H→invisible decays where H is produced according to the standard model via vector boson fusion, Z(ℓℓ)H, and W/Z(had)H, all performed with the ATLAS detector using 36.1 fb−1 of pp collisions at a...
Article
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Silicon pixel detectors are at the core of the current and planned upgrade of the ATLAS experiment at the LHC. Given their close proximity to the interaction point, these detectors will be exposed to an unprecedented amount of radiation over their lifetime. The current pixel detector will receive damage from non-ionizing radiation in excess of 1015...
Article
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A search for heavy charged long-lived particles is performed using a data sample of 36.1 fb−1 of proton-proton collisions at s=13 TeV collected by the ATLAS experiment at the Large Hadron Collider. The search is based on observables related to ionization energy loss and time of flight, which are sensitive to the velocity of heavy charged particles...
Article
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A search for new particles decaying into a pair of top quarks is performed using proton-proton collision data recorded with the ATLAS detector at the Large Hadron Collider at a center-of-mass energy of s=13 TeV corresponding to an integrated luminosity of 36.1 fb−1. Events consistent with top-quark pair production and the fully hadronic decay mode...
Article
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The performance of identification algorithms (“taggers”) for hadronically decaying top quarks and W bosons in pp collisions at \(\sqrt{s}\) = 13 TeV recorded by the ATLAS experiment at the Large Hadron Collider is presented. A set of techniques based on jet shape observables are studied to determine a set of optimal cut-based taggers for use in phy...
Article
Full-text available
It has been found that the theoretical predictions for W and Z boson cross sections, and for the W boson charge asymmetry, which are labelled as NNPDF3.1 [1] have in fact been calculated using the NNPDF3.0 PDF set [2] instead.
Article
Full-text available
Inclusive and differential cross-sections for the production of a top-quark pair in association with a photon are measured with proton-proton collision data corresponding to an integrated luminosity of 36.1 \(\text{ fb }^{-1}\), collected by the ATLAS detector at the LHC in 2015 and 2016 at a centre-of-mass energy of 13 \(\text {TeV}\). The measure...
Article
Full-text available
A bstract This paper describes a search for events with one top-quark and large missing transverse momentum in the final state. Data collected during 2015 and 2016 by the ATLAS experiment from 13 TeV proton–proton collisions at the LHC corresponding to an integrated luminosity of 36.1 fb ⁻¹ are used. Two channels are considered, depending on the le...
Article
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An observation of electroweak W ± Z production in association with two jets in proton–proton collisions is presented. The data collected by the ATLAS detector at the Large Hadron Collider in 2015 and 2016 at a centre-of-mass energy of s=13 TeV are used, corresponding to an integrated luminosity of 36.1fb ⁻¹ . Events containing three identified lept...
Article
Full-text available
A bstract Cross-sections of associated production of a Higgs boson decaying into bottomquark pairs and an electroweak gauge boson, W or Z , decaying into leptons are measured as a function of the gauge boson transverse momentum. The measurements are performed in kinematic fiducial volumes defined in the ‘simplified template cross-section’ framework...
Article
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A bstract Constraints on selected mediator-based dark matter models and a scalar dark energy model using up to 37 fb ⁻¹ $$ \sqrt{s} $$ s = 13 TeV pp collision data collected by the ATLAS detector at the LHC during 2015-2016 are summarised in this paper. The results of experimental searches in a variety of final states are interpreted in terms of a...
Article
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A bstract A search for singly produced vector-like quarks Q , where Q can be either a T quark with charge +2/3 or a Y quark with charge −4/3, is performed in proton–proton collision data at a centre-of-mass energy of 13 TeV corresponding to an integrated luminosity of 36.1 fb ⁻¹ , recorded with the ATLAS detector at the LHC in 2015 and 2016. The an...
Article
Full-text available
A search is performed for localised excesses in dijet mass distributions of low-dijet-mass events produced in association with a high transverse energy photon. The search uses up to 79.8 fb−1 of LHC proton–proton collisions collected by the ATLAS experiment at a centre-of-mass energy of 13 TeV during 2015–2017. Two variants are presented: one which...
Article
Full-text available
A measurement of the associated production of a top-quark pair (tt¯) with a vector boson (W, Z) in proton-proton collisions at a center-of-mass energy of 13 TeV is presented, using 36.1 fb−1 of integrated luminosity collected by the ATLAS detector at the Large Hadron Collider. Events are selected in channels with two same- or opposite-sign leptons...
Article
Full-text available
This Letter presents a search for the production of a long-lived neutral particle (Zd) decaying within the ATLAS hadronic calorimeter, in association with a standard model (SM) Z boson produced via an intermediate scalar boson, where Z→ℓ+ℓ− (ℓ=e, μ). The data used were collected by the ATLAS detector during 2015 and 2016 pp collisions with a center...
Article
Full-text available
A measurement of production cross sections of the Higgs boson in proton-proton collisions is presented in the H→ττ decay channel. The analysis is performed using 36.1 fb−1 of data recorded by the ATLAS experiment at the Large Hadron Collider at a center-of-mass energy of √s=13 TeV. All combinations of leptonic (τ→ℓvv¯ with ℓ=e,μ) and hadronic (τ→ha...