In order to increase the event rate and operate at a larger instantaneous luminosity, the LHCb detector has undergone a big upgrade for the new data-taking period in Run 3. An important part of the upgrade is the improvement of the trigger system, which is now fully software-based, and performs an offline-quality track reconstruction. A precise knowledge of the position and orientation of all LHCb sub-detectors in real-time is crucial to maximize the trigger efficiency and obtain the best-quality data for physics analyses. This poster summarizes the foreseen real-time alignment and calibration procedure, with a focus on the alignment of the LHCb tracker, which has a large impact on the reconstructed track \chi^2, affecting the number of tracks that can be reconstructed as well as the primary and secondary vertex resolution and the track momentum resolution. These are all quantities employed by most of the trigger lines for the selection of events. Results from the Run 3 commissioning period are presented, showing the impact of the VELO and SciFi alignment on the vertex and track resolution. The improvements seen on the reconstructed mass distributions of \K^{0}_s and \Lambda^0 hadrons between two different stages of the LHCb alignment are also shown as an example.

The LHCb experiment has been recently upgraded in most of all its subdetector, including the Upstream Tracker. The installation of the four planes of silicon microstrip was concluded in the beginning of 2023 and now the detector is under the commissioning phase. In this poster, the integration process of the Upstream Tracker in the global data taking of the LHCb is described, focusing on the data acquisition firmware, the decoding algorithm and control and data analysis software. Details on the latest progresses and on the detector performance will be given, including operational conditions, detector performance tests and the first data captured with the dedicated firmware.

At the start of 2023, a vacuum control incident resulted in damage to the thin aluminium box that separates the secondary vacuum of the LHCb experiment from the primary vacuum of the LHC, resulting in major disruption to LHCb data-taking. A detailed study of the resulting deformation of the box is presented, by reconstructing hadronic interactions in the material of the box. The deformations across both sides is found to be between 32-34mm, such that the normal procedure by which the two halves of the Vertex Locator (VELO) are opened during LHC beam injection and closed during data taking became impossible.

Monte Carlo event generators (MCEGs) play a crucial role in understanding the physics of particle colliders. They serve as essential components for experimental analyses and are extensively used by both theorists and experimentalists to make predictions and prepare for future experiments. MCEGs incorporate free parameters, primarily associated with soft and non- perturbative physics modeling, the values of which calibrated through the process of tuning. This process is based on two independent libraries, RIVET and PROFESSOR, within the LbMCSubmit framework, specifically for the purpose of tuning various parameters in PYTHIA 8.204, including cross- sections, color- reconnection, flavor composition, and multiparton interactions. The methodology, benefits, and implications of this approach are comprehensively discussed, highlighting the effective utilization of these tools for advancing Monte Carlo event generator capabilities through accurate parameter tuning.

The two LHCb Ring Imaging Cherenkov detectors, providing charged hadron discrimination, underwent a major upgrade to withstand with the five-fold increase in the instantaneous luminosity delivered to the experiment in Run 3. The opto-electronics chain has been completely changed by employing approximately 3100 Multianode Photomultiplier Tubes and a brand-new frontend electronics. The number of detected Cherenkov photons per track is one of the crucial parameters driving the charged hadron identification performance and therefore the sensitivity to single photons at rates up to 100 MHz/cm2 is of paramount importance. In order to uniformy the response of the detectors and to maximise the efficiency, the calibration data acquired in the experiment has been used to equalise the single photon gain over approximately 200k channels by keeping at the same time the backgrounds under control. The data-taking procedures, data analysis techniques and the results of the calibration are presented.

The LHCb experiment underwent a major upgrade to run with a five-fold increase in the instantaneous luminosity. All the subdetectors now employ a triggerless readout, while the trigger architecture has been changed to cope with larger input rates. The operations of the upgraded LHCb detector started in 2022 and the data collected by the experiment have been used to determine the first global performance figure of merit. In particular, the charged hadron identification performance, provided in LHCb by two Ring Imaging Cherenkov detectors and taking as input the tracking information, has been evaluated by using the dataset collected in 2022 and 2023. The performance is determined by using dedicated calibration streams and the procedure is therefore also providing a validation of the new LHCb Run 3 dataflow model. The early hadron identification performance achieved in Run 3 is presented.

Ratios of branching fractions constitute a powerful test of lepton flavour universality (LFU), since they have accurate Standard Model (SM) predictions and could be sensitive to New Physics processes that violate LFU. A significant tension remains between the SM theoretical values and the experimental measurements performed by LHCb and other experiments. In this poster, the status of the analysis aiming at the simultaneous measurement of the ratios R(D(*)0)= BR(B->D(*)0 Tau Nu)/BR(B->D(*)0 Mu Nu), where D(*)0 is either D0 or D*0 meson, is presented, with the tau lepton reconstructed by using 3-prong hadronic decays.

The upgraded LHCb detector has started data taking in Run 3 with a completely new DAQ system, in which every LHC crossing is reconstructed in detail before trigger decisions are made (Real Time Analysis). This system is key to the physics objectives of LHCb performance, and the collaboration is now considering how it can be enhanced for the higher luminosities targeted by its Upgrade II. Here we describe an R&D effort towards a real-time tracking device based on a distributed system of FPGAs, that would provide early reconstruction primitives at the pre-build level to accelerate the reconstruction process in HLT1 and HLT2. We show first results from a prototype device currently running opportunistically on live LHCb data during Run 3 physics data taking. This technology forms the basis of a project for accelerating the computationally expensive and important task of track reconstruction in the forward region. This project is currently being considered by the LHCb collaboration as a LS3 enhancement.

High-energy physics is facing increasingly computational challenges in real-time event reconstruction for the near-future high-luminosity era, especially for charged particles track finding. In this poster, I present a recently developed algorithm for track reconstruction based on the minimisation of an Ising-like Hamiltonian with a linear algebra approach: the track finding problem is translated into a sparse system of linear equations, which is suitable to be solved on a quantum computer, using the Harrow-Hassadim-Lloyd (HHL) algorithm. This approach can potentially provide an exponential speedup as a function of the number of input hits over its classical counterpart, in spite of the current limitations due to the HHL Hamiltonian simulation and readout problems. The performance of our algorithm has been assessed using simulated events in the LHCb Vertex Locator, while the quantum implementation has been tested using smaller toy-model events.

According to the Standard Model (SM), the lepton flavour is conserved in electroweak transitions, meaning that the different flavors of leptons do not mix or transform into each other. Observation of Lepton-Flavour Violating (LFV) processes would be a clear signal of physics beyond the Standard Model. This poster discusses recent results on charged LFV searches with b-hadron decays at the LHCb experiment.