Detailed measurements of the properties of the 125 GeV Higgs boson are fundamental for the understanding of the electroweak symmetry breaking mechanism. Measurements of the Higgs boson in the diboson final states allow to study the gauge and loop induced couplings of the Higgs boson both in production and decay modes. This talk summarizes ATLAS measurements of the 125 GeV Higgs boson in decays...
Detailed measurements of the properties of the 125 GeV Higgs boson are fundamental for the understanding of the electroweak symmetry breaking mechanism. Measurements of the Higgs boson in fermion final states allow to study the Yukawa couplings of the Higgs boson through the decay mode and the gauge couplings of the Higgs boson through the production mode. This talk summarizes ATLAS...
Latest results of SM Higgs measurements in the fermionic final state are presented, as well as results of searches for BSM Higgs bosons using the CMS detector at LHC. Results are based on pp collision data collected at centre-of-mass energies of 8 and 13 TeV. Results have been interpreted according to different extensions of the Standard Model, such as 2HDM, MSSM, NMSSM. These searches look...
Higgs boson and double Higgs boson productions suffer from large higher order corrections. This is true also when they are accompanied by further jets. The most precise results rely on computations in an effective theory where the heavy quark loops, mediating the coupling between the Higgs boson and the gluons, are integrated out. As the LHC is delivering more and more precise data, it is...
The associated production of the Higgs boson with top quarks should allow the direct observation of the coupling of the Higgs boson to top quarks. The channel also benefits from a large cross-section increase between 8 and 13 TeV. ATLAS results for the search of the 125 GeV Higgs boson in the ttH production mode will be presented.
The latest results of searches for the Standard Model Higgs boson produced in association with a top quark-antiquark pair (ttH), or with a single top quark (tHq) are presented. The analyses have been performed using the 13 TeV pp collisions data recorded by the CMS experiment in 2015 and 2016. The results are presented in the form of the best fit to the signal strength measured with respect to...
Theoretical uncertainties in the simulation of $t\bar{t}b\bar{b}$ production represent one of the main obstacles that still hamper the observation of Higgs-boson production in association with top-quark pairs in the $H \to b\bar{b}$. We present a next-to-leading order (NLO) simulation of $t\bar{t}b\bar{b}$ production with massive b-quarks matched to the Pythia within the POWHEG method with the...
In this talk the latest results for soft gluon resummation at fixed invariant mass for $pp \to t\bar{t}H$ will be presented. The resummation is extended beyond next-to leading logarithmic accuracy. The invariant mass resummation results will be presented in the form of the inclusive cross section and the invariant mass distribution, including scale uncertainty.
Studying the pair production of Higgs bosons at the LHC is important as it is sensitive to the Higgs trilinear coupling. It therefore allows for a direct test of the Higgs potential and the mechanism of electroweak symmetry breaking.
Since the heavy top limit provides only a poor description of Higgs boson pair production, a precise theoretical description of this process requires the...
The production of pairs of Higgs bosons at hadron colliders provides unique information on the Higgs sector and on the mechanism underlying electroweak symmetry breaking (EWSB). Most studies have concentrated on the gluon fusion production mode which has the largest cross section. However, despite its small production rate, the vector-boson fusion channel can also be relevant since even small...
We compute top-quark induced contributions to the hadronic decay of the standard model Higgs boson, to the fourth order in $\alpha_s$. We work in an effective theory in which the Higgs boson may couple directly to bottom quarks and gluons. Our results prove to be of a comparable size to the purely massless contributions available in the literature.
We study the effects of dimension six operators on the Higgs decay into
four lepton channel. The calculation of new matrix element is performed
in the Higgs basis and it is implemented in a Monte Carlo event generator.
The code also allows the calculation in other popular choices of basis for
the dimension six operators. We have considered all the relevant operators,
both the CP-even and...
The impact of several dimension-six operators of the standard
model effective field theory relevant for vector-boson fusion and associated Higgs boson production at the LHC is investigated at next-to-leading order accuracy in QCD, including matching to parton showers. The importance of the subsequent reduction of the theoretical uncertainties in improving the possible discrimination between...
Some theories predict Lepton Flavour Violating decays of the Higgs boson, while other predict enhanced decay rates into new light pseudoscalar bosons "a" or invisible particles. Also enhanced rates in rare decay modes like Phi-photon are considered. In this presentation the latest ATLAS results on searches for such non-standard and rare decays will be discussed.
The discovery of lepton flavour violating interactions will be striking evidence for physics beyond the Standard Model. Focusing on the three decays τ∓→μ±μ∓μ∓, τ∓→e±μ∓μ∓ and τ∓→e∓μ∓μ±, we evaluate the discovery potential of current and future high-energy colliders to probe lepton flavour violation in the τ sector. Based on this potential we determine the expected constraints on parameters of...
The presence of a non-baryonic dark matter component in the Universe is inferred from the observation of its gravitational interaction. If dark matter interacts weakly with the Standard Model it would be produced at the LHC, escaping the detector and leaving a large missing transverse momentum as their signature. The ATLAS detector has developed a broad and systematic search program for dark...
Many theories predict candidates to the dark matter particles that are light enough to be produced at the LHC. This talk presents the searches for dark matter at CMS in events with missing transverse energy, focusing on the recent results obtained using data collected in 2016.
The large set of proton-proton collision data recorded by CMS in 2016 at a centre-of-mass energy of 13 TeV is the basis for the first results on electroweak production of supersymmetric particles in LHC Run 2. Results for the pair production of charginos and neutralinos are presented based on the analysis of final states with one or more leptons and interpreted under several assumptions for...
Many supersymmetry models feature gauginos and also sleptons with masses less than a few hundred GeV. These can give rise to direct pair production rates at the LHC that can be observed in the data sample recorded by the ATLAS detector. The talk presents recent results of searches for chargino and neutralino direct production in final states with leptons using LHC Run 2 data.
I discuss the feasibility to search for supersymmetry in the decays of heavy Z' bosons, predicted by GUT-inspired U(1)' models, by investigating final states with charged leptons and missing energy in pp collisions at the LHC. I also investigate decays into pairs of the lightest MSSM neutralinos, which are Dark Matter candidates, and update the exclusion limits on the Z' mass, accounting for...
We study the naturalness properties of the B − L Supersymmetric Standard Model (BLSSM) and compare them to those of the Minimal Supersymmetric Standard Model (MSSM) at both low (i.e., Large Hadron Collider) energies and high (i.e., unification) scales. By adopting standard measures of naturalness, we assess that, in presence of full unification of the additional gauge couplings and...
Naturalness arguments for weak-scale supersymmetry favour supersymmetric partners of the third generation quarks with masses not too far from those of their Standard Model counterparts. Top or bottom squarks with masses less than about one TeV can also give rise to direct pair production rates at the LHC that can be observed in the data sample recorded by the ATLAS detector. The talk presents...
Supersymmetric partners of top and bottom quarks are among the most promising candidates for the next-to-lightest supersymmetric particle. Searches for the pair production of top and bottom squarks have been performed in final states with 0, 1, or 2 charged leptons, jets, and missing transverse energy. The results are obtained using proton-proton collisions at sqrt(s) = 13 TeV, recorded by the...
The proton-proton collisions at sqrt{s} = 13 TeV at the LHC have increased the ATLAS sensitivity to production of strongly produced supersymmetric particles. If R-parity is not conserved, these particles may decay to jets and leptons, and lightest supersymmetric particles may decay into many leptons with or without missing transverse momentum. Several supersymmetric models also predict...
Weak scale supersymmetry is one of the best motivated and studied extensions of the Standard Model. This talk summarises recent ATLAS results on searches for supersymmetric squarks and gluinos, including third generation squarks produced via the decay of gluinos. The searches involved final states containing jets (possibly identified as coming from b-quarks), missing transverse momentum and...
Results are presented from searches for strong production of supersymmetric particles in events with at least one leptons, jets, and missing transverse energy. The data set consists of proton-proton collisions at sqrt(s) = 13 TeV, recorded by the CMS experiment in 2016. The results are interpreted in the framework of several simplified models of gluino and squark pair production.
The discovery of a Higgs boson at the Large Hadron Collider (LHC) motivates searches for physics beyond the Standard Model (SM) in channels involving coupling to the Higgs boson. A search for a massive resonance decaying into a standard model Higgs boson (h) and a W or Z boson or two a standard model Higgs bosons is performed. Final states with different number of leptons or photons and where...
Beyond the standard model theories like Extra-Dimensions and Composite Higgs scenarios predict the existence of very heavy resonances compatible with a spin 0 (Radion),spin 1 (W’, Z’) and spin 2 (Graviton) particle with large branching fractions in pairs of standard model bosons and negligible branching fractions to light fermions. We present an overview of searches for new physics containing...
Searches for high mass BSM scalars have been carried out with the CMS detector at LHC, based on pp collision data collected at centre-of-mass energies of 7, 8, and 13 TeV. The talk presents the latest results and gives a brief review of earlier results.
Searches for BSM particles using the 126 GeV Higgs boson have been carried out with the CMS detector at LHC, based on pp collision data collected at centre-of-mass energies of 7, 8, and 13 TeV. The talk presents the latest results and gives a brief review of earlier results.
Several theories beyond the Standard Model, like the 2HDM, predict the existence of high mass neutral and charged Higgs particles. Searches for such additional Higgs bosons have been performed in bosonic and fermionic decay modes of the additional Higgs bosons. This talk summarizes ATLAS searches for heavy Higgs boson resonances with LHC Run 2 data collected in 2015 and 2016.
During the last two years the LHC produced pp collisions at the record center-of-mass energy of 13 TeV. The sensitivity of searches for new phenomena with a high mass scale greatly benefited from the energy increase with respect to the LHC run-1 data. Events with two hadronic jets in the final state are of particular interest: new phenomena produced in parton collisions are likely to produce...
This presentation will be focused on searches for new physics with dijets at CMS using data collected in the LHC Run 2. Both heavy and light dijet mass resonances will be investigated. Results from the dijet angular analysis will also be discussed.
The high-precision HERA data allow searches for "beyond the Standard Model" contributions to electron-quark scattering up to TeV scales. Combined H1 and ZEUS measurements of inclusive deep inelastic cross sections in neutral and charged current $ep$ scattering are considered, corresponding to a luminosity of around 1 fb$^{−1}$. A new approach to the beyond the Standard Model analysis of the...
We show the effects of the inclusion of Photon-Initiated processes in the di-lepton channel.
We include the contribution of quasi-real photon through the Equivalent Photon Approximation, of real photons through the recently released QED PDFs, and (as novelty) of the mixed real- quasi-real photons interaction.
We comment on the systematic uncertainties arising from the inclusion of those terms...
The NA62 experiment at CERN collected a large sample of charged kaon decays in flight with a minimum bias trigger in 2007. Upper limits on the rate of the charged kaon decay into a muon and a heavy neutral lepton (HNL) obtained from this data are reported for a range of HNL masses.
Vector like quarks appear in many theories beyond the Standard Model as a way to cancel the mass divergence for the Higgs boson. The current status of the ATLAS searches for the production of vector like quarks will be reviewed for proton-proton collisions at 13 TeV. This presentation will address the analysis techniques, in particular the selection criteria, the background modeling and the...
Many models of physics beyond the Standard Model (SM) contain enhanced couplings to massive standard model particles like the W,Z,Higgs, and top. We present a review of non-SUSY based searches for new physics beyond the SM in final states containing these heavy particles, using proton-proton collision data collected with the CMS detector at the CERN LHC. The models probed can contain heavy...
Studying how ATLAS and CMS searches for supersymmetry in the t tbar + MET final state constrain scenarios with a fermionic top partner and a dark matter candidate, we show that the efficiencies of the considered searches are quite similar for scalar and fermionic top partners. Therefore, in general, efficiency maps for stop–neutralino simplified models can also be applied to fermionic...
Many theories beyond the standard model predict new phenomena which decay to leptons and jets. Searches for new physics models with these signatures are performed using the ATLAS experiment at the LHC. The results reported here use the pp collision data sample collected in 2015 and 2016 by the ATLAS detector at the LHC with a centre-of-mass energy of 13 TeV.
Many physics scenarios beyond the standard model predict the existence of new particles decaying to dilepton, multilepton, and lepton+MET final states. This talk presents searches for BSM physics in these three final states at CMS, focusing on the recent results obtained using data collected at the LHC in 2016.
