The concept of lepton flavour universality (LFU), according to which the three lepton families are equivalent except for their masses, is a cornerstone prediction of the Standard Model (SM). LFU can be violated in models beyond the SM by new physics particles that couple preferentially to certain generations of leptons. In the last few years, hints of LFU violation have been observed in both tree-level b → c ν and loop-level b → s transitions. These measurements, combined with the tensions observed in angular observables and branching fractions of rare semileptonic b decays, point to a coherent pattern of anomalies that could soon turn into the first observation of physics beyond the SM. These proceedings review the anomalies seen by the LHC experiments and the B factories, and give an outlook for the near future.

In this report I will describe the latest results of the ALICE, ATLAS, CMS, and LHCb experiments in the fields of production, spectroscopy, and properties of heavy hadrons. In particular, I will concentrate on measurements of quarkonium production cross sections, polarization, and mass, on measurements of production cross sections and lifetimes of open heavy flavors, on the recent observations of new states and decay modes, and on other searches for new and exotic hadrons.

Latest results on the heavy flavour production and spectroscopy at the LHC are reviewed. These include measurements of production rates of the charmed and beauty hadrons, and observations of new excited charmed and beauty hadrons and exotic states.

This work presents the latest results on open heavy-flavour production in protonproton, proton-lead, lead-lead and xenon-xenon collisions from the ALICE, ATLAS, CMS and LHCb Collaborations at the LHC. Physics MotivationThe production of heavy-flavour hadrons (those containing charm or beauty quarks) is one of the key probes of the colour-deconfined and strongly interacting state of matter, the Quark-Gluon Plasma (QGP) that is formed in ultrarelativistic heavy-ion collisions [1]. Due to their large masses with respect to the QCD energy scale (m c,b Λ QCD ), they are formed at early times in hard (high-Q 2 ) partonic scatterings. This means that they experience the full evolution of the system before decaying, and so studying their behaviour in heavy-ion collisions gives a unique handle on the transport coefficients of the medium.In the context of heavy-ion physics, it is necessary to study multiple different collision systems to fully understand the observed effects. Proton-proton collisions are used as a baseline for crosssection measurements in the absence of a medium, and can also be used to test predictions made by perturbative QCD (pQCD) calculation frameworks. Minimum-bias proton-lead collisions can also be compared with lead-lead collisions in order to disentangle the role of cold nuclear matter (CNM) effects that arise simply from the presence of a nucleus in the initial state, such as nuclear shadowing, from those occurring due to the presence of a deconfined medium. Lead-lead and, more recently, xenon-xenon collisions at the LHC, form the basis of the QGP studies among the LHC experiments, and comparisons between the two systems at similar numbers of binary nucleon-nucleon collisions (N coll ) can provide an insight into the path length dependence of energy loss in the medium.Charmed baryon production has also recently become an important topic in heavy-ion physics. Previous studies in the strangeness sector have shown an enhancement in the baryonto-meson ratio of Λ baryons compared with kaons due to the effect of recombination of strange quarks with light quarks in the medium. Similar studies in the charm and beauty sectors will shed light on the fragmentation and hadronisation mechanisms of heavy quarks.Heavy flavours are measured in the four LHC experiments using a variety of techniques: the reconstruction of electrons and muons from the semileptonic decays of open heavy-flavour hadrons (ALICE, ATLAS), where it is possible to separate the beauty contribution from arXiv:1809.01899v1 [nucl-ex]

The conventional description of heavy-flavour hadron production in pp collisions is based on a factorisation approach, assuming universal fragmentation functions among collision systems. Recent results on heavy-flavour baryon measurements from the LHC experiments show tensions with model calculations based on this approach and employing fragmentation functions constrained from e + e − and e − p collision experiments. In this contribution, the most recent results from ALICE, ATLAS, CMS and LHCb experiments on the heavy-flavour hadron production in pp collisions at the TeV scale are reported. The comparison with the theoretical predictions that address the baryon enhancement in hadronic collisions at the LHC is also discussed.

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The use of machine learning is increasing at the LHC experiments including both the ATLAS and LHCb collaborations, in terms of the number of users, the breadth of applications, and the set of different techniques under study. While traditionally applied in the context of improving the final analysis selection for a given physics result, machine learning is now also being applied in many other places, including object reconstruction, object calibration, object identification, simulation, and automation. The variety of machine learning tools being used is also expanding, and many areas are benefiting from the use of deep learning methods. It is expected that this growth in machine learning within particle physics will continue, as the large and rapidly increasing datasets provide the perfect environment to develop and refine new machine learning algorithms which can maximally exploit the complex data.

The search and study of rare decays of B hadrons and of the 𝜏 lepton are among the most promising approaches of putting the Standard Model of particle physics to the test. In recent years, the study of these decays, and in particular of flavour-changing neutral current decays 𝑏 → 𝑠ℓℓ, helped shed light on a set of tensions in the data with respect to theoretical predictions for branching ratios, angular distributions and lepton flavour universality. In this work, the most recent results in the study of rare heavy-flavour decays at the Large Hadron Collider experiments are presented.