Precise determinations of the CKM matrix element ∣Vub∣ are essential for testing the consistency of the Standard Model and for probing possible sources of flavour-changing new physics. LHCb offers a unique environment to study ∣Vub​∣ using semileptonic decays of various species of beauty hadrons, exploiting excellent vertexing, particle identification, and kinematic reconstruction. This contribution summarises the current status of ∣Vub∣ measurements at LHCb and discusses prospects for improved precision with larger data sets, refined analysis techniques, and improved theoretical inputs.

We present a study of the charmless three-body decays $B^{0}_{(s)} \to K^{0}_{S} h^{+} h^{\prime -}$, where $h$ is either a $\pi$ or a $K$, corresponding to six final states whose branching fractions are measured simultaneously. These decays are suppressed and, in certain cases, are dominated by penguin topologies. The data sample collected at \mbox{LHCb} between 2011 and 2018 is used for these measurements, corresponding to an integrated luminosity of $9~\mathrm{fb}^{-1}$. In a previous paper, using just Run~1 data, no conclusive evidence was found for the existence of $B^{0}_{s} \to K^{0}_{S} K^{+} K^{-}$. With this larger dataset, $B^{0}_{s} \to K^{0}_{S} K^{+} K^{-}$ is observed for the first time with a statistical significance corresponding to $8.6$ standard deviations. The poster will present the essential steps of the analysis. First, the selection procedure is outlined: a trigger, a cut-based preselection, and two boosted decision trees based on particle identification and on topological variables. Second, the fit strategy is described: separate fit components are included for the $B^{0}$ and $B^{0}_{s}$ signal peaks, partially reconstructed signal decays, crossfeed structures due to hadron misidentification, and combinatorial background. Third, the efficiency correction procedure is presented. This includes a description of the variation of efficiency across the Dalitz plane, and uses a data-driven estimate of the signal distribution in the Dalitz plane to obtain the weighted-average efficiency. Finally, the new branching-fraction results are presented. Compared to the previous \mbox{LHCb} measurement, the uncertainties on the ratios of branching fractions are reduced by a factor of $2$ to $3$, due both to the larger data sample and to improvements in the analysis procedure. The tools developed for this branching-fraction analysis are being reused in ongoing amplitude analyses of $B^{0}_{(s)} \to K^{0}_{S} h^{+} h^{\prime -}$ decays.

Charmonium mesons are among the most important probes of deconfined QCD matter. A complete understanding of their production and interaction with the medium created in the collision is necessary to disentangle genuine hot-matter effects from cold nuclear matter effects. To achieve this, charmonium production must be measured in different collision systems over a wide energy range. Fixed-target collisions at LHCb, enabled by the SMOG2 system, complement studies performed in collider mode and provide access to kinematic regions not explored by other fixed-target experiments. In Run 2, the LHCb collaboration provided results on J/ψ-to-D0 and ψ(2S) -to-J/ψ ratios in p Ne and PbNe collisions at √sN N = 68.5 GeV. In Run 3 the SMOG2 system has so far enabled an expanded set of targets, including He, Ne, Ar, O2, D2 and H2, the latter serving as a proxy for pp collisions at √sNN = 113 GeV. Here we present the first LHCb fixed-target heavy-flavor results from Run 3, with a focus on charmonia, and discuss the prospects for upcoming analyses aimed at improving the precision of and extending the Run 2 results. In addition, we present the first results on the determination of centrality classes in lead-target datasets from Run 3, as this variable is crucial for most heavy-ion physics analyses. Taken together, these results highlight the unique opportunities offered by the LHCb fixed-target programme for studying quarkonium production and nuclear matter effects, and advancing our understanding of QCD matter under extreme conditions.

Two sets of 6 fast-pulsed vertical and two sets of 4 fast-pulsed horizontal dilutor kicker magnets form part of the so-called LHC beam dumping system, which removes the counter-rotating beams safely from the collider onto an absorber block. Each vertical and horizontal diluter magnet is powered by a pulse generator via a low-impedance transmission line resulting in maximum damped sinusoidal voltage of 16 kV and a maximum damped sinusoidal current pulse of 30 kA. The fast-pulsed dilutor kickers magnets, MKBV and MKBH, consist of a steel yoke with excitation coils, which are immersed in the accelerator vacuum. As part of a consolidation program, high-voltage insulated coil spares will be manufactured. The coils are composed of conductor bars of quasi-rectangular cross-section, junction pieces, and conductor contact pieces. The coils are completely insulated for the 16 kV and 10 kV peak voltages. The surface of the insulation is coated with a resistive layer and connected to earth. The connector contact terminals are moulded sockets, surrounded by stress rings. This paper describes the design of the MKBV and MKBH kicker magnets, focusing on the fabrication processes and validation tests for both types of coils.

The High-Luminosity Large Hadron Collider (HL-LHC) will deliver a five- to seven-fold increase in instantaneous luminosity relative to the original LHC design, and approximately a three-fold increase compared to Run-3 operation, significantly increasing detector readout volumes and placing substantially higher demands on the trigger and data-acquisition systems. To meet these challenges, the ATLAS Event Filter Tracking group is evaluating heterogeneous computing platforms to reduce the size, cost, and power consumption of the event-processing farm. Options where key algorithms of the processing are offloaded to either FPGA or GPU accelerator cards are compared directly to a traditional CPU-only farm. This contribution presents an FPGA-based implementation of the pattern-recognition stage in the tracking pipeline, developed using High-Level Synthesis and integrated within the ATLAS Athena software framework using the OpenCL cross-platform programming model. We describe the architecture, firmware design choices, and workflow for hardware–software co-execution. Performance studies compare physics efficiency and throughput of FPGA implementation against other technologies, demonstrating the potential of FPGA acceleration for the HL-LHC Event Filter. Pattern Recognition algorithm in FPGA Pipeline The Event Filter Tracking group is evaluating FPGA technology as a platform for implementing data-preparation and tracking algorithms for the ATLAS experiment. In this workflow, data from the ATLAS Inner Tracker (ITk) subsystem is transferred into the Athena software framework, which launches the FPGA-based processing pipeline via OpenCL cross-platform APIs, thus transferring approximately 50% of the tracking algorithms onto the FPGA.

We report on the first observation of the semitauonic $b$-baryon decay $\Lambda_b^0 \to \Lambda_c^+ \tau^- \bar{\nu}_\tau$~\cite{ref1,ref2} using $3\,\mathrm{fb}^{-1}$ of LHCb Run~1 data. This decay provides a stringent test of Lepton Flavour Universality (LFU) and offers complementary sensitivity to potential New Physics beyond mesonic anomalies such as $R(D^{*})$. The analysis reconstructs the $\tau$ lepton in its three-prong hadronic decay and employs a novel ``inversion cut'' to suppress prompt backgrounds. The signal is extracted via a three-dimensional template fit to $q^2$, $\tau$ lifetime, and BDT output, achieving a significance of $6.1\sigma$. The LFU ratio is measured to be $R(\Lambda_c^+) = 0.242 \pm 0.026\,(\mathrm{stat}) \pm 0.040\,(\mathrm{syst}) \pm 0.059\,(\mathrm{ext})$, consistent with the Standard Model within $1.1\sigma$. This result provides an important baryonic test of LFU and can be interpreted in the context of theoretical correlations with mesonic observables. Prospects for improved precision using the full Run~1+2+3 datasets are also discussed.

Light hadrons constitute the bulk of particle production in heavy-ion collisions. Its properties, such as the production cross-sections of different hadron species or their average transverse momentum, are sensitive to both collective phenomena and the initial state of heavy-ion collisions. Bulk physics measurements in small collision systems can reveal the interplay between initial- and final-state effects in heavy-ion collisions, and can provide new insights into the origins of collective phenomena. The LHCb detector, with its high-resolution tracking system and its hadron ID capabilities, is perfectly suited for these studies in the forward region. In this contribution, new results on bulk measurements in small systems will be presented.

The $\phi$ meson is a unique probe of strange quark dynamics in high-energy nuclear collisions. The $\phi$ meson's mass lies at the threshold between perturbative and nonperturbative QCD. Consequently, $\phi$ production provides sensitivity to both regimes. In heavy-ion collisions, $\phi$-meson production is senstive to strange-quark coalescence in quark-gluon plasma. The $\phi$ meson's net-zero strangeness means that $\phi$ production measurements can help disentangle the physical mechanisms behind strangeness enhancement in high-energy hadron and nucleaer collisions. The LHCb detector's hadron identification capabilities allow for precise studies of $\phi$ meson production in nuclear collisions. In addition, the SMOG system allows LHCb to study production in fixed-target collisions. New measurements of $\phi$ production in both collider and fixed-target configurations will be presented.

Ultra-peripheral collisions provide a unique environment to study pomeron- and photon-induced reactions with heavy nuclei. These interactions can produce a wide range of final state particles, from light vector mesons to heavy quarkonia, and probe potentially exotic phenomena. With a fast and flexible DAQ, full particle ID, and the ability to reconstruct very low pt particles, LHCb is uniquely well suited to study final states with leptons, hadrons or photons. Also, using the HeRSCheL detector, the far forward event activity can be detected and used to tag events with nuclear break-up. In this contribution, we will present recent LHCb results from ultra-peripheral heavy ion collisions and discuss how these impact our understanding new exotic phenomena, the partonic structure of nuclei and hadronization in small systems.

At CERN, we probe the fundamental structure of particles that make up everything around us. We do so using the world’s largest and most complex scientific instruments. This visual exhibition focuses mainly on photos, offers visitors the opportunity to explore CERN through 18 posters.