R. Covarelli

The discovery of the Higgs boson in 2012, by the ATLAS and CMS experiments, was a success achieved with only a percent of the entire dataset foreseen for the LHC. It opened a landscape of possibilities in the study of Higgs boson properties, Electroweak Symmetry breaking and the Standard Model in general, as well as new avenues in probing new physics beyond the Standard Model. Six years after the discovery, with a conspicuously larger dataset collected during LHC Run 2 at a 13 TeV centre-of-mass energy, the theory and experimental particle physics communities have started a meticulous exploration of the potential for precision measurements of its properties. This includes studies of Higgs boson production and decays processes, the search for rare decays and production modes, high energy observables, and searches for an extended electroweak symmetry breaking sector. This report summarises the potential reach and opportunities in Higgs physics during the High Luminosity phase of the LHC, with an expected dataset of pp collisions at 14 TeV, corresponding to an integrated luminosity of 3 ab$^{-1}$. These studies are performed in light of the most recent analyses from LHC collaborations and the latest theoretical developments. The potential of an LHC upgrade, colliding protons at a centre-of-mass energy of 27 TeV and producing a dataset corresponding to an integrated luminosity of 15 ab$^{-1}$, is also discussed.

This report comprises the outcome of five working groups that have studied the physics potential of the high-luminosity phase of the LHC (HL-LHC) and the perspectives for a possible future high-energy LHC (HE-LHC).The working groups covered a broad range of topics: Standard Model measurements, studies of the properties ofthe Higgs boson, searches for phenomena beyond the Standard Model, flavor physics of heavy quarks and leptonsand studies of QCD matter at high density and temperature.The work is prepared as an input to the ongoing process of updating the European Strategy for Particle Physics,a process that will be concluded in May 2020.

Vector-boson scattering (VBS) processes probe the innermost structure of electroweak interactions in the Standard Model, and provide a unique sensitivity for new physics phenomena affecting the gauge sector. In this review, we report on the salient aspects of this class of processes, both from the theory and experimental point of view. We start by discussing recent achievements relevant for their theoretical description, some of which have set important milestones in improving the precision and accuracy of the corresponding simulations. We continue by covering the development of experimental techniques aimed at detecting these rare processes and improving the signal sensitivity over large backgrounds. We then summarise the details of the most relevant VBS signatures and review the related measurements available to date, along with their comparison with Standard-Model predictions. We conclude by discussing the perspective at the upcoming Large Hadron Collider runs and at future hadron facilities.

The discovery of the Higgs boson in 2012, by the ATLAS and CMS experiments, was a success achieved with only a percent of the entire dataset foreseen for the LHC. It opened a landscape of possibilities in the study of Higgs boson properties, Electroweak Symmetry breaking and the Standard Model in general, as well as new avenues in probing new physics beyond the Standard Model. Six years after the discovery, with a conspicuously larger dataset collected during LHC Run 2 at a 13 TeV centre-of-mass energy, the theory and experimental particle physics communities have started a meticulous exploration of the potential for precision measurements of its properties. This includes studies of Higgs boson production and decays processes, the search for rare decays and production modes, high energy observables, and searches for an extended electroweak symmetry breaking sector. This report summarises the potential reach and opportunities in Higgs physics during the High Luminosity phase of the LHC, with an expected dataset of pp collisions at 14 TeV, corresponding to an integrated luminosity of 3 ab$^{-1}$. These studies are performed in light of the most recent analyses from LHC collaborations and the latest theoretical developments. The potential of an LHC upgrade, colliding protons at a centre-of-mass energy of 27 TeV and producing a dataset corresponding to an integrated luminosity of 15 ab$^{-1}$, is also discussed.

This document summarises the talks and discussions happened during the VBSCan Split17 workshop, the first general meeting of the VBSCan COST Action network. This collaboration is aiming at a consistent and coordinated study of vector-boson scattering from the phenomenological and experimental point of view, for the best exploitation of the data that will be delivered by existing and future particle colliders.

We present a parton-level study of electro-weak production of vector-boson pairs at the Large Hadron Collider, establishing the sensitivity to a set of dimension-six operators in the Standard Model Effective Field Theory (SMEFT). Different final states are statistically combined, and we discuss how the orthogonality and interdependence of different analyses must be considered to obtain the most stringent constraints. The main novelties of our study are the inclusion of SMEFT effects in non-resonant diagrams and in irreducible QCD backgrounds, and an exhaustive template analysis of optimal observables for each operator and process considered. We also assess for the first time the sensitivity of vector-boson-scattering searches in semileptonic final states.

This is the third out of five chapters of the final report [1] of the Workshop on Physics at HL-LHC, and perspectives on HE-LHC [2]. It is devoted to the study of the potential, in the search for Beyond the Standard Model (BSM) physics, of the High Luminosity (HL) phase of the LHC, defined as $3~\mathrm{ab}^{-1}$ of data taken at a centre-of-mass energy of $14~\mathrm{TeV}$, and of a possible future upgrade, the High Energy (HE) LHC, defined as $15~\mathrm{ab}^{-1}$ of data at a centre-of-mass energy of $27~\mathrm{TeV}$. We consider a large variety of new physics models, both in a simplified model fashion and in a more model-dependent one. A long list of contributions from the theory and experimental (ATLAS, CMS, LHCb) communities have been collected and merged together to give a complete, wide, and consistent view of future prospects for BSM physics at the considered colliders. On top of the usual standard candles, such as supersymmetric simplified models and resonances, considered for the evaluation of future collider potentials, this report contains results on dark matter and dark sectors, long lived particles, leptoquarks, sterile neutrinos, axion-like particles, heavy scalars, vector-like quarks, and more. Particular attention is placed, especially in the study of the HL-LHC prospects, to the detector upgrades, the assessment of the future systematic uncertainties, and new experimental techniques. The general conclusion is that the HL-LHC, on top of allowing to extend the present LHC mass and coupling reach by $20-50\%$ on most new physics scenarios, will also be able to constrain, and potentially discover, new physics that is presently unconstrained. Moreover, compared to the HL-LHC, the reach in most observables will generally more than double at the HE-LHC, which may represent a good candidate future facility for a final test of TeV-scale new physics.

The successful operation of the Large Hadron Collider (LHC) and the excellent performance of the ATLAS, CMS, LHCb and ALICE detectors in Run-1 and Run-2 with $pp$ collisions at center-of-mass energies of 7, 8 and 13 TeV as well as the giant leap in precision calculations and modeling of fundamental interactions at hadron colliders have allowed an extraordinary breadth of physics studies including precision measurements of a variety physics processes. The LHC results have so far confirmed the validity of the Standard Model of particle physics up to unprecedented energy scales and with great precision in the sectors of strong and electroweak interactions as well as flavour physics, for instance in top quark physics. The upgrade of the LHC to a High Luminosity phase (HL-LHC) at 14 TeV center-of-mass energy with 3 ab$^{-1}$ of integrated luminosity will probe the Standard Model with even greater precision and will extend the sensitivity to possible anomalies in the Standard Model, thanks to a ten-fold larger data set, upgraded detectors and expected improvements in the theoretical understanding. This document summarises the physics reach of the HL-LHC in the realm of strong and electroweak interactions and top quark physics, and provides a glimpse of the potential of a possible further upgrade of the LHC to a 27 TeV $pp$ collider, the High-Energy LHC (HE-LHC), assumed to accumulate an integrated luminosity of 15 ab$^{-1}$.

We describe several studies to measure the charged track reconstruction efficiency and asymmetry of the BABAR detector. The first two studies measure the tracking efficiency of a charged particle using τ and initial state radiation decays. The third uses the τ decays to study the asymmetry in tracking, the fourth measures the tracking efficiency for low momentum tracks, and the last measures the reconstruction efficiency of KS0 particles. The first section also examines the stability of the measurements vs. BABAR running periods.

We analyze LHC processes involving interactions of two electroweak bosons and two Higgs bosons, VVHH, where V is a W or Z boson, in terms of their sensitivity to Standard Model Effective Field Theory (SMEFT) effects. We examine the current experimental results of the CMS collaboration in the context of an 8-dimensional SMEFT. We show that the constraints arising from producing vector-boson-fusion Higgs pairs on the operators that modify the quartic gauge-Higgs interactions are already comparable to or more stringent than those published in the analysis of the vector-boson scattering processes using CMS. We study changes to such constraints when introducing perturbative unitarity bounds and investigate the potential for new experimental final states, such as associated production of ZHH. Finally, we show the prospects for the high-luminosity phase of the LHC.

The BABAR detector has operated nearly 200 Resistive Plate Chambers (RPCs), constructed as part of an upgrade of the forward endcap muon detector, for the past two years.The RPCs experience widely different background and luminosity-driven singles rates (0.01-10 Hz/cm 2 ) depending on position within the endcap.Some regions have integrated over 0.3 C/cm 2 .RPC efficiency measured with cosmic rays is high and stable.The average efficiency measured with beam is also high.However, a few of the highest rate RPCs have suffered efficiency losses of 5-15%.Although constructed with improved techniques and minimal use of linseed oil, many of the RPCs, which are operated in streamer mode, have shown increased dark currents and noise rates that are correlated with the direction of the gas flow and the integrated current.Studies of the above aging effects are presented and correlated with detector operating conditions.

Loop-induced $ZZ$ production can be enhanced by the large gluon flux at the LHC, and thus should be taken into account in relevant experimental analyses. We present for the first time the results of a fully exclusive simulation based on the matrix elements for loop-induced $ZZ+0$, 1, 2-parton processes at leading order, matched to parton showers. The new description is studied and validated by comparing it with well-established simulation with jets from parton showers. We find that the matched simulation provides a state-of-the-art description of the final-state jets. We also briefly discuss the physics impact on vector boson scattering measurements at the LHC, where event yields are found to be smaller by about 40% in a vector boson scattering $ZZjj$ baseline search region, compared to previous simulations. We hence advocate relevant analyses to employ a more accurate jet description for the modeling of the loop-induced process.

The BaBar detector has operated over 200 2nd generation Resistive Plate Chambers (RPCs) in the forward endcap since 2002. Many chambers have increased noise rates and high-voltage currents. These aging symptoms are correlated with the integrated RPC current as expected, but also depend on the rate and direction of the gas flow, indicating that pollutants produced in the gas can accelerate aging of downstream RPC surfaces. HF produced by decomposition of the Freon 134a component of the BaBar RPC gas in electric discharges has been proposed as the main pollutant. This paper presents measurements of HF production and absorption rates in BaBar RPCs. Since many of the highest rate chambers in the forward endcap were converted to avalanche mode operation, a comparison of HF production in streamer and avalanche mode RPCs is made. Correlations between the HF production rate and other chamber operating conditions were also explored.

A bstract We analyse the sensitivity to beyond-the-Standard-Model effects of hadron-collider processes involving the interaction of two electroweak and two Higgs bosons, VVHH, with V being either a W or a Z boson. We examine current experimental results by the CMS collaboration in the context of a dimension-8 extension of the Standard Model in an effective-field-theory formalism. We show that constraints from vector-boson-fusion Higgs-pair production on operators that modify the Standard Model VVHH interactions are already comparable with or more stringent than those quoted in the analysis of vector-boson-scattering final states. We study the modifications of such constraints when introducing unitarity bounds, and investigate the potential of new experimental final states, such as ZHH associated production. Finally, we show perspectives for the high-luminosity phase of the LHC.

The BaBar detector is currently operating nearly 200 Resistive Plate Chambers (RPCs), constructed as part of an upgrade of the forward endcap muon detector in 2002. Although the average RPC efficiency remains high, numerous changes in the RPC performance (increased currents and rates) have been observed. A few of the highest rate RPCs have suffered efficiency losses of more than 15%. Several types of efficiency loss have been observed. Tests with humidified gas have shown that some of the lost efficiency is recoverable. However, efficiency losses in the highest rate regions have not yet improved with humid gases.

At the startup of the LHC, the CMS data acquisition is expected to be able to sustain an event readout rate of up to 100 kHz from the Level‐1 trigger. These events will be read into a large processor farm which will run the “High‐Level Trigger” (HLT) selection algorithms and will output a rate of about 150 Hz for permanent data storage. In this report HLT performances are shown for selections based on muons, electrons, photons, jets, missing transverse energy, τ leptons and b quarks: expected efficiencies, background rates and CPU time consumption are reported as well as relaxation criteria foreseen for a LHC startup instantaneous luminosity.

This document summarises the talks and discussions happened during the VBSCan Mid-Term Scientific Meeting workshop. The VBSCan COST action is dedicated to the coordinated study of vector boson scattering (VBS) from the phenomenological and experimental point of view, for the best exploitation of the data that will be delivered by existing and future particle colliders.

Triple and quartic gauge self-couplings among the least known Standard Model structures and their interplay with the Higgs mechanism, giving rise to final states such as vector-boson scattering, probes the core of the Electro-weak Symmetry Breaking mechanism.Recent ATLAS and CMS measurements on the 13-TeV LHC dataset are reviewed concerning vector-boson fusion and scattering, which are electroweak processes with a large sensitivity on possible anomalies in gauge self-couplings.Results are presented in terms of measurements of fiducial and total crosssections as well as polarization of outgoing vector bosons.

This document reports the first year of activity of the VBSCan COST Action network, as summarised by the talks and discussions happened during the VBSCan Thessaloniki 2018 workshop. The VBSCan COST action is aiming at a consistent and coordinated study of vector-boson scattering from the phenomenological and experimental point of view, for the best exploitation of the data that will be delivered by existing and future particle colliders.

This document summarises the talks and discussions happened during the VBSCan Mid-Term Scientific Meeting workshop. The VBSCan COST action is dedicated to the coordinated study of vector boson scattering (VBS) from the phenomenological and experimental point of view, for the best exploitation of the data that will be delivered by existing and future particle colliders.

An overview of recent ATLAS and CMS results on the Standard-Model Higgs boson properties will be presented, with particular focus on preliminary property measurements performed using up to 3.2 fb-1 data collected in 2015 at the center of mass energy of 13 TeV. Presented at IFAE2016 XV Incontri di Fisica delle Alte Energie IL NUOVO CIMENTO Vol. ?, N. ? ? Recent results on the Higgs boson from the LHC R. Covarelli() for the ATLAS and CMS collaborations () Universita e Sezione INFN di Torino Torino, Italy Summary. — An overview of recent ATLAS and CMS results on the StandardModel Higgs boson properties will be presented, with particular focus on preliminary property measurements performed using up to 3.2 fb−1 data collected in 2015 at the center of mass energy of 13 TeV. PACS 14.80.Bn – Standard-model Higgs bosons. PACS 12.60.Fr – Extensions of electroweak Higgs sector.

ATLAS and CMS results on the Standard-Model Higgs boson properties are presented.The measurements performed using the full dataset collected during Run1 (∼ 5 fb -1 at 7 TeV and ∼ 20 fb -1 at 8 TeV) have been presented.Newer results obtained with Run2 data (up to 3.2 fb -1 ) collected at the center of mass energy of 13 TeV will be presented.

Constraints are set on the Higgs boson decay width, Gamma_H, using off-shell production and decay to ZZ in the four-lepton (4l), or two-lepton-two-neutrino (2l2nu) final states. The analysis is based on the data collected in 2012 by the CMS experiment at the LHC, corresponding to an integrated luminosity L = 19.7 fb^{-1} at sqrt(s) = 8 TeV. A maximum-likelihood fit of invariant mass and kinematic discriminant distributions in the 4l case and of transverse mass or missing energy distributions in the 2l2nu case is performed. The result of it, combined with the 4l measurement near the resonance peak, leads to an upper limit on the Higgs boson width of Gamma_H < 4.2 x Gamma_H^SM at the 95% confidence level, assuming Gamma_H^SM = 4.15 MeV.

Constraints are set on the Higgs boson decay width, Gamma_H, using off-shell production and decay to ZZ in the four-lepton (4l), or two-lepton-two-neutrino (2l2nu) final states. The analysis is based on the data collected in 2012 by the CMS experiment at the LHC, corresponding to an integrated luminosity L = 19.7 fb^{-1} at sqrt(s) = 8 TeV. A maximum-likelihood fit of invariant mass and kinematic discriminant distributions in the 4l case and of transverse mass or missing energy distributions in the 2l2nu case is performed. The result of it, combined with the 4l measurement near the resonance peak, leads to an upper limit on the Higgs boson width of Gamma_H &lt; 4.2 x Gamma_H^SM at the 95% confidence level, assuming Gamma_H^SM = 4.15 MeV.

Thanks to the excellent performances of ATLAS and CMS in triggering on muon signals and reconstructing these particles down to low transverse momentum, large samples of heavy-flavored hadrons have been collected in the 2011 LHC run at sqrt(s) = 7 TeV. The analysis of these samples has enabled both experiments to perform competitive measurements of heavy-flavor properties, such as quarkonium polarization, lifetime and CP-violation measurements, hadron spectroscopy and branching ratios of rare B decays.

This document presents the determination of the J/ψ and ψ(2S) differential cross sections in pp collisions at 7 TeV, as a function of transverse momentum and in several rapidity ranges, on the basis of the 2010 data collected by CMS, corresponding to an integrated luminosity of 37 pb−1. The b → J/ψ and b → ψ(2S) fractions are also determined, enabling to separate the prompt and non-prompt contributions and compare to theory calculations. We also report the measurement of the γ(1S), γ(2S), and γ(3S) differential cross sections as a function of transverse momentum and rapidity.

B-physics will be one of the key physics themes at the Large Hadron Collider (LHC).B-hadrons are an ideal tool for advancing our current understanding of the flavour sector of the Standard Model (SM), and searching for effects originating from physics beyond the SM, thanks to the large production rate and the fact that B-hadrons are relatively easy to trigger on and identify due to their long lifetime and decays to muons.In this talk, we present the estimated sensitivities of the CMS experiment with early LHC data and the very first observations in the December 2009 pilot run.The first B-physics measurements with the CMS experiment include charmonium production (both prompt J/ψ production and J/ψ from B decays), ϒ production, exclusive final states B → J/ψK ( * ) and b b correlations.Besides probing the heavy quark properties for the first time at the LHC energy, these measurements are also important tools for understanding and calibrating the detector, providing standard candles for upcoming measurements, and giving input for Monte Carlo tuning.

The first results of the CMS silicon-strip tracker alignment analysis are presented using the data from cosmic tracks, optical survey information, and the laser alignment system at the Tracker Integration Facility at CERN.During several months of operation in the spring and summer of 2007, about five million cosmic events were collected with a partially active CMS Tracker.With these data, the first alignment of the active silicon modules has been performed using three different statistical approaches.Comparison with simulations show that the achieved alignment precision can be estimated as 50 (80) µm in the outer (inner) part of the tracker barrel.Within this statistical precision, no instabilities of Tracker structures were found under temperature changes ranging from +15 • C to -15 • C and under mechanical stress of the system.

We describe measurements of CP and CPT violation parameters in B^0B^0bar oscillations, performed at BaBar by using BBbar events collected at the Y(4S) mass peak. These are obtained from two different B-reconstruction methods, namely: searching for two inclusive semileptonic B^0 decays in an event or partially reconstructing one of the B^0 mesons in the D* l nu_l channel. The results are in agreement with one another and with the most recent theoretical calculations in the Standard Model scenario.

This document summarises the talks and discussions happened during the VBSCan Split17 workshop, the first general meeting of the VBSCan COST Action network. This collaboration is aiming at a consistent and coordinated study of vector-boson scattering from the phenomenological and experimental point of view, for the best exploitation of the data that will be delivered by existing and future particle colliders.

We present recent searches for high-mass scalar bosons ($H$) decaying to light-Higgs ($h$) or gauge ($V$) bosons in the CMS experiment, using 13 TeV proton-proton collision data from the RunII of the LHC machine. Namely, searches for $H \rightarrow hh$, $A \rightarrow Zh$, and $H \rightarrow ZZ$ are reported. Model-independent constraints on cross-sections or parameter exclusions in specific theory frameworks beyond the Standard Model, such as 2-Higgs-Doublet Models, are presented.

The Monte Carlo modeling adopted at the CMS experiment is reviewed. Choices of matrix-element generators are explained and new CMS PYTHIA8 underlying-event tunes are presented. The new tunes are obtained using minimum bias and underlying event observables exploiting Monte Carlo configurations with consistent parton distribution functions and strong coupling constant values in the matrix element and the parton shower, at leading order (LO), next-to-leading order (NLO) and next-to-next-to-leading order (NNLO). Validation and performance studies are presented by comparing the predictions of the new tunes to a wide range of different CMS measurements at 7, 8 and 13 TeV.

This document reports the first year of activity of the VBSCan COST Action network, as summarised by the talks and discussions happened during the VBSCan Thessaloniki 2018 workshop. The VBSCan COST action is aiming at a consistent and coordinated study of vector-boson scattering from the phenomenological and experimental point of view, for the best exploitation of the data that will be delivered by existing and future particle colliders.

This document reports the first year of activity of the VBSCan COST Action network, as summarised by the talks and discussions happened during the VBSCan Thessaloniki 2018 workshop. The VBSCan COST action is aiming at a consistent and coordinated study of vector-boson scattering from the phenomenological and experimental point of view, for the best exploitation of the data that will be delivered by existing and future particle colliders.

This document reports the first year of activity of the VBSCan COST Action network, as summarised by the talks and discussions happened during the VBSCan Thessaloniki 2018 workshop. The VBSCan COST action is aiming at a consistent and coordinated study of vector-boson scattering from the phenomenological and experimental point of view, for the best exploitation of the data that will be delivered by existing and future particle colliders.

The authors present model-independent measurements of the branching fractions {Beta}(B{sup 0} {yields} D*{sub s}{sup +} D*{sup -}) and {Beta}(D{sub s}{sup +} {yields} {phi}{pi}{sup +}) based on 19.3 fb{sup -1} of data collected by the BABAR detector at the PEP-II e{sup +}e{sup -} B Factory. Neutral B-meson decays to the D*{sub s}{sup +}D*{sup -} final state are selected with a partial reconstruction of the D*{sub s}{sup +}; that is, only the D*{sup -} and the soft photon from the decay D*{sub s}{sup +} {yields} D{sub s}{sup +}{gamma} are reconstructed. The branching fraction {Beta}(B{sup 0} {yields} D*{sub s}{sup +} D*{sup -}) is extracted from these event yields, while {Beta}(D{sub s}{sup +} {yields} {phi}{pi}{sup +}) is determined by combining this result with a previous measurement of the product {Beta}(B{sup 0} {yields} D*{sub s}{sup +} D*{sup -}) x {Beta}(D{sub s}{sup +} {yields} {phi}{pi}{sup +}) with partial reconstruction of the D*{sup -}. They obtain the following preliminary results: {Beta}(B{sup 0} {yields} D*{sub s}{sup +} D*{sup -}) = (1.50 {+-} 0.16 {+-} 0.12)%, {Beta}(D{sub s}{sup +} {yields} {phi}{pi}{sup +}) = (4.7 {+-} 0.6 {+-} 0.8)% where the first error is statistical, and the second systematic.