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First Measurement of = 4 Hypernuclei and Antihypernuclei at the LHC
No full textIn this Letter, the first evidence of the antihypernucleus is presented, along with the first measurement at the LHC of the production of (anti)hypernuclei with mass number , specifically (anti) and (anti). In addition, the antiparticle-to-particle ratios for both hypernuclei ( and ) are shown, which are sensitive to the baryochemical potential of the strongly interacting matter created in heavy-ion collisions. The results are obtained from a data sample of central Pb--Pb collisions, collected during the 2018 LHC data taking at a center-of-mass energy per nucleon pair of = 5.02 TeV. The yields measured for the average of the charge-conjugated states are found to be for the (anti) and for the (anti), and the measured antiparticle-to-particle ratios are in agreement with unity. The presence of (anti) and (anti) excited states is expected to strongly enhance the production yield of these hypernuclei. The yield values exhibit a combined deviation of from the theoretical ground-state-only expectation, while the inclusion of the excited states in the calculations leads to an agreement within with the present measurements. Additionally, the measured (anti) and (anti) masses are compatible with the world-average values within the uncertainties
First Measurement of the Decay Dynamics in the Semileptonic Transition of into the Axial-Vector Meson
No full textDielectron production in central PbPb collisions at = 5.02 TeV
No full textNo data abstract available
Study of the analog response of the silicon tracking system sensors of the CBM experiment using the LTspice package
No full textAn Online GPU Hit Finder for the STS Detector in the CBM Experiment
No full textThe Compressed Baryonic Matter (CBM) experiment at FAIR will operate at interaction rates up to 10 MHz, generating data streams averaging 500 GB/s. This necessitates efficient online reconstruction capabilities, particularly for the Silicon Tracking System (STS), which is the key detector for track reconstruction and contributes a large fraction of the expected data volume. We present a GPU-accelerated hit reconstruction chain for the STS that achieves a 128 speedup over the sequential CPU implementation. The implementation features optimized data structures reducing memory footprint, parallel algorithms for sorting, cluster finding, and hit reconstruction, and portability across GPU architectures. Our custom merge sort outperforms library implementations by 10 % while using 33 % less memory. Cluster finding employs a twophase approach with atomic operations for thread-safe connections between signal clusters. Even before GPU acceleration, algorithmic improvements provide a 3 speedup in single-threaded execution. Both NVIDIA and AMD GPUs achieve comparable performance of approximately 0.12 s on a timeframe containing 1000 Au+Au events. The reconstruction chain was successfully deployed during the May 2024 mCBM beamtime, processing data rates up to 2.4 GB/s in real-time, demonstrating its viability for CBM’s triggerless data acquisition approach
Performance evaluation of the prototype CBM Silicon Tracking System: Results from operation in the mCBM at the SIS18 demonstrator experiment
No full textRF power limits of 4-rod RFQs
No full textThere is a long tradition at the Institute of Applied Physics at Frankfurt University of new developments for 4-rod. In the past years, the RF-power front8ier of 4-Rod RFQs has been explored resulting in prototype tests that pushed the power dissipation in cw-mode into the regime of 4-Vane RFQs. For instance, during performance tests of a 6 stem prototype, it could be demonstrated that a 4-Rod RFQ at high frequencies could reach up to 120 kW per meter. In these tests the input power and the electrode voltage was observed using gamma spectroscopy. An overview of activities at the IAP on this topic will be provided
Heavy-light mesons from a flavour-dependent interaction
No full textWe introduce a new framework for the physics of heavy-light mesons, whose key element is the effective incorporation of flavour-dependent contributions into the corresponding bound-state and quark gap equations. These terms originate from the fully-dressed quark-gluon vertices appearing in the kernels of these equations, and provide a natural distinction between “light” and “heavy” quarks. In this approach, only the classical form factor of the quark-gluon vertex is retained, and is evaluated in the so-called “symmetric” configuration. The standard Slavnov-Taylor identity links this form factor to the quark wave-function, allowing for the continuous transition from light to heavy quarks through the mere variation of the current quark mass in the gap equation. The method is used to compute the masses and decay constants of specific pseudoscalars and vector heavy-light systems, showing good overall agreement with both experimental data and lattice simulations
Photonuclear tomography in ultraperipheral heavy-ion collisions
No full textWe present a theoretical investigation of photonuclear tomography as a novel technique for probing the internal structure of nuclei. In this approach, ultraperipheral heavy-ion collisions (UPCs) serve as a source of intense fluxes of virtual photons, which induce coherent production of vector mesons. By analyzing the probabilities and cross sections of these photon-induced processes, we propose a methodology for reconstructing the spatial distribution of nucleons within the nucleus. Our framework provides a systematic way to access information on the nuclear geometry probed in UPCs, offering new opportunities for studies of nuclear structure using particle production as a probe. Numerical calculations for selected examples illustrate the feasibility and potential of this method