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Modelling of Compton scattering within the Fast ATLAS Track Simulation
No full textThe Fast ATLAS Tracking Simulation (FATRAS) is a computationally efficient tool being developed to simulate the particle interactions within the inner detector of the ATLAS experiment. The development of accurate fast-simulation tools is essential to handling the increased event rates of the upcoming High-Luminosity Large Hadron Collider. This project addresses the lack of Compton scattering modelling in FATRAS by implementing the Klein-Nishina (KN) differential cross-section and developing a parametrised model for the KN total cross-section. The implemented model of Compton scattering demonstrates strong agreement when compared to benchmark Geant4 simulations. Further, a promising parametrisation of the integrated KN cross-section is presented, offering an efficient alternative to direct integration. Future work involves benchmarking the computational performance of the differential cross-section implementation and integrating the total cross-section model into FATRAS
DeepMET: Improving missing transverse momentum estimation with a deep neural network
No full textAt hadron colliders, the net transverse momentum of particles that do not interact with the detector (missing transverse momentum) is a crucial observable in many analyses. In the standard model, missing transverse
momentum originates from neutrinos. Many beyond-the-standard-model particles such as dark matter candidates are also expected to leave the experimental apparatus undetected. This note presents a novel missing transverse momentum estimator DeepMET, developed for the CMS experiment at the LHC, that is based on deep neural networks. DeepMET produces a weight for each reconstructed particle based on its properties. The estimator is the negative vector sum over all reconstructed particles of their weighted transverse momenta. Compared with other estimators currently employed by CMS, DeepMET improves the missing transverse momentum resolution by 10--20\%, shows improvement for a wide range of final states, is easier to train, and is more resilient against the effects of additional proton-proton interactions accompanying the collision of interest. A version of DeepMET that is less dependent on correct reconstruction of the hard scattering vertex position is also presented
Study of individual Tiles aging using Cesium scans
No full textATLAS Tile Calorimeter (TileCal) is a sampling hadronic calorimeter and an essential component of the ATLAS detector at the LHC. The active material, made of plastic scintillating tiles, produces light when traversed by charged particles. This light is transmitted to photomultiplier tubes (PMTs) by wavelength shifting fibres in a way that several scintillators are read by the same PMT. The High Luminosity-LHC (HL-LHC) program will extend the TileCal lifetime for 20 years more than originally designed. The detector performance is affected by the increased exposure to radiation, which will degrade the TileCal optics, and by natural ageing. This degradation is different between tiles because some of them are closer to the interaction point than others. Consequently, the spread in the response of all the tiles connected to the same PMT can increase during data taking spoiling the uniformity in the response. In order to evaluate this uniformity, the response from the TileCal scintillators and fibres was determined by exploring information from the dedicated calibration system that employs a cesium source. In this calibration, the source produces a particular signal while it goes through the detector, which is fitted to determine the responses of the tiles and fibres. A summary of our results showing that the variations in the spread of the response are less than 1% in most of the PMTs, except for some exceptions where variations are between 2-8%, will be presented in this talk
Polish national input to the 2026 update of the European Strategy for Particle Physics
No full textThe Polish high energy physics (HEP) community fully recognizes the urgent need to host at CERN a flagship project implementing a broad, long-term, and comprehensive vision of particle physics research and pursuing technological advances. Thus, we give preference and declare willingness to actively engage and participate in every aspect of the FCC project (both FCC-ee and FCC-hh), particularly accelerator development, detector construction, theoretical calculations, and physics analyses. As the e+e- Higgs Factory is the top priority for our field, the proposal to build a linear collider facility at CERN, opening up complementary physics prospects, should be considered as the second option. Polish teams declare strong support and are fully committed to contribute to the full exploitation of all aspects of the physics potential of the LHC and the HL-LHC programmes. To ensure the long-term development of particle physics, we also support the continuation of the high-field magnet research programme, as well as investigating other scenarios including, in particular, linear acceleration techniques and new acceleration technologies such as plasma acceleration, the muon collider and Gamma Factory. In addition, CERN should continue to provide support to fixed-target programmes at SPS as well as other non-collider and non-accelerator experiments at CERN. Participation in major projects conducted in and outside Europe should also be fostered. Education, communication, and outreach of particle physics are of paramount importance for the future of our field. An increased effort coordinated at the European level and resources allocated in all Member States are essential to effectively support future large-scale particle physics projects
Visit by Mr João António Mira Gomes, Ambassador, Permanent Representative of Portugal to the United Nations Office and other international organisations in Geneva, Portugal
No full textVisit by His Excellency Mr João António Mira Gomes, Ambassador, Permanent Representative of Portugal to the United Nations Office and other international organisations in Geneva, Portuguese Republi
Top properties with ATLAS
No full textRun 2 of the LHC has provided more data with which to study the properties of the top quark with ATLAS. New analysis techniques have allowed for increasingly precise measurements of the top quark mass, Yukawa coupling and lepton flavour universality. Additionally, new properties have been observed, such as quantum entanglement. This contribution present highlights of these measurements
IT Lightning Talks: session #26
No full textI am currently exploring the OpenMediaVault NAS (Network Attached Storage) solution, and I have set up a personal mini-cloud solution for family and friends into a Raspberry Pi
Search for solar axions produced through the axion-electron coupling using a new GridPix detector at CAST
No full textWe present a search for solar axions produced through the axion-electron coupling (g) using data from a novel 7-GridPix detector installed at the CERN Axion Solar Telescope (CAST). The detector, featuring ultra-thin silicon nitride windows and multiple veto systems, collected approximately 160 hours of solar tracking data between 2017–2018. Using machine learning techniques and the veto systems, we achieved a background rate of 1.06 × 10 keV cm s at a signal efficiency of about 80% in the 0.2 to 8 keV range. Analysis of the data yielded no significant excess above background, allowing us to set a new upper limit on the product of the axion-electron and axion-photon couplings of g · g < 7.35 × 10 GeV at 95% confidence level for axion masses below 10 meV. This result improves upon the previous best helioscope limit and demonstrates the potential of GridPix technology for rare event searches. Additionally, we derived a limit on the axion-photon coupling of g < 9.0 × 10 GeV at 95% CL, which, while not surpassing CAST’s best limit, provides complementary constraints on axion models.We present a search for solar axions produced through the axion-electron coupling using data from a novel 7-GridPix detector installed at the CERN Axion Solar Telescope (CAST). The detector, featuring ultra-thin silicon nitride windows and multiple veto systems, collected approximately 160 hours of solar tracking data between 2017-2018. Using machine learning techniques and the veto systems, we achieved a background rate of at a signal efficiency of about in the - range. Analysis of the data yielded no significant excess above background, allowing us to set a new upper limit on the product of the axion-electron and axion-photon couplings of at confidence level. This result improves upon the previous best helioscope limit and demonstrates the potential of GridPix technology for rare event searches. Additionally, we derived a limit on the axion-photon coupling of at CL, which, while not surpassing CAST's best limit, provides complementary constraints on axion models