Giuseppe Callea

The production of jets and prompt isolated photons at hadron colliders provides stringent tests of perturbative QCD. We present the latest measurements of photon+jets and diphoton production using proton-proton collision data collected by the ATLAS experiment at the LHC. The measurements are compared to state-of-the-art NLO and NNLO predictions.

We present a novel approach to construct a color singlet tagger, i.e.~an observable that is able to discriminate the decay of a color-singlet into two jets from a two-jet background in a different color configuration. We do this by explicitly taking the ratio of the corresponding leading-order matrix elements in the soft limit, thus obtaining an observable that is provably optimal within our approximation. We call this observable the ``jet color ring" and we compare its performance to other color-sensitive observables such as jet pull and dipolarity. We also assess the performance of the jet color ring in simulations by applying it to the case of the hadronic decays of a boosted Higgs boson and of an electroweak boson.

The jet colour ring is a novel colour tagger observable designed to separate the decay of a colour-singlet into two jets from a two-jet background in a different colour configuration.Simulation studies in the case of the production of a boosted Higgs boson decaying in two b-quarks and an associate electroweak boson, showed notable discriminator powers when comparing the jet colour ring performances with other observables.These results are opening a wide scenario for further studies.

The jet colour ring is a novel colour tagger observable designed to separate the decay of a colour-singlet into two jets from a two-jet background in a different colour configuration. Simulation studies in the case of the production of a boosted Higgs boson decaying in two b-quarks and an associate electroweak boson, showed notable discriminator powers when comparing the jet colour ring performances with other observables. These results are opening a wide scenario for further studies.

The production of jets and prompt isolated photons at hadron colliders provides stringent tests of perturbative QCD. We present the latest measurements of photon+jets and diphoton production using proton-proton collision data collected by the ATLAS experiment at the LHC. The measurements are compared to state-of-the-art NLO and NNLO predictions.

The dynamics of isolated-photon plus jet production in pp collisions at √ s = 13 TeV were studied with the ATLAS detector at the LHC, using a dataset with an integrated luminosity of 3.2 fb -1 .The photons were reconstructed for photon transverse energies larger than 125 GeV.The jets were identified using the anti-k t algorithm with radius parameter R=0.4 and selected in the rapidity range |y| < 2.37, for transverse momenta p T > 100 GeV.Measurements of isolated-photon plus jet cross sections are presented as functions of the photon transverse energy, the jet transverse momentum, the azimuthal separation between the selected photon and the jet, the photon-jet invariant mass and the scattering angle in the photon-jet centre-of-mass system.The leadinglogarithm parton-shower preditions from SHERPA and PYTHIA as well as the next-to-leading order QCD calculations from JETPHOX and multi-leg plus parton shower NLO SHERPA are compared to the measurements.

This contribution gives an overview of the recent measurements of the differential cross sections for final states involving photons and/or jets at the centre-of-mass energies of 8 and 13 TeV, published by the ATLAS Collaboration. The results are compared with several next-to-leading order calculations and with the latest predictions of various Monte Carlo generators. New measurements of transverse energy-energy correlations and their associated asymmetries in multi-jet events at 8 TeV are also presented. Both measurements are used to extract the strong coupling constant and test the renormalization group equation.

We analyze the recently discovered phenomena in elastic proton-proton scattering at the LHC, challenging the standard Regge-pole theory: the low-|t| "break" (departure from the exponential behavior of the diffraction cone), the accelerating rise with energy of the forward slope B(s, t = 0), absence of secondary dips and bumps on the cone, and the role of the odderon in the forward phase of the amplitude, ρ(13 TeV) = 0.1 ± 0.01 and, especially, its contribution at the dip region, measured recently by TOTEM.Relative contributions from different components to the scattering amplitude are evaluated from the fitted model.

We present a novel approach to construct a color tagger, i.e. an observable that is able to discriminate the decay of a color-singlet into two jets from a two-jet background in a different color configuration.We do this by explicitly taking the ratio of the corresponding leading-order matrix elements in the soft limit, thus obtaining an observable that is provably optimal within our approximation.We call this observable the "jet color ring" and we compare its performance to other color-sensitive observables such as jet pull and dipolarity.We also assess the performance of the jet color ring in simulations by applying it to the case of the hadronic decays of a boosted Higgs boson and of an electroweak boson.

This is the 11 th edition in a series of workshops that had been previously organised in Poland

We present a novel approach to construct a color tagger, i.e. an observable that is able to discriminate the decay of a color-singlet into two jets from a two-jet background in a different color configuration. We do this by explicitly taking the ratio of the corresponding leading-order matrix elements in the soft limit, thus obtaining an observable that is provably optimal within our approximation. We call this observable the color and we compare its performance to other color-sensitive observables such as jet pull and dipolarity. We also assess the performance of the jet color ring in simulations by applying it to the case of the hadronic decays of a boosted Higgs boson and of an electroweak boson.

The jet colour ring is a novel colour tagger observable designed to separate the decay of a colour-singlet into two jets from a two-jet background in a different colour configuration. Simulation studies in the case of the production of a boosted Higgs boson decaying in two b-quarks and an associate electroweak boson, showed notable discriminator powers when comparing the jet colour ring performances with other observables. These results are opening a wide scenario for further studies.

The jet colour ring is a novel colour tagger observable designed to separate the decay of a colour-singlet into two jets from a two-jet background in a different colour configuration. Simulation studies in the case of the production of a boosted Higgs boson decaying in two b-quarks and an associate electroweak boson, showed notable discriminator powers when comparing the jet colour ring performances with other observables. These results are opening a wide scenario for further studies.