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ATLAS Outreach and Education
No full textThe ATLAS Experiment on the Large Hadron Collider at CERN is one of the largest most complex scientific instruments ever constructed. It has been built and operated by an international collaboration of over 5900 members of 103 nationalities from 243 institutes around the world. While the scientific goals and results of the experiment are continually reported to colleagues in the field through conferences, journals and seminars, the collaboration makes a dedicated effort to engage other key audiences with the excitement of its achievements. These audiences range from young children and students, members of the media, politicians and scientists in the same or different fields. Efforts include effective sustained online communication, development of educational material, including Masterclasses and open data programmes, creation of exhibitions and events at festivals, hosting of local and virtual visits to the experiment, and much more. The work is led by members of the ATLAS Collaboration, supported by a dedicated Outreach team including expertise in education and communication. This report summarizes the recent developments and plans, as well as the challenges faced by the current fragmented media landscape
International Conference on High Performance Computing, Networking, Storage, and Analysis (SC '25)
No full textToward neutron / gamma discrimination with proportional counter using artificial intelligence
No full textExtending the neutron detection capabilities of the ROSPEC SP2-1 proportional counter below 50 keV requires effective discrimination between neutron and gamma-ray signals at low energies. To address this challenge, we use a digital acquisition system, then apply signal processing and artificial intelligence techniques to analyze the data. The results showed that a CNN-based trained model can successfully distinguish noise from event signals in the recorded data. Key pulse features, such as rise time and amplitude, are extracted from the true signals to generate a two-dimensional plot of rise time versus amplitude, which facilitates the discrimination of neutron from gamma components. The application of the unsupervised clustering algorithm DBSCAN on this feature space shows limitations in accurately identifying low-amplitude gamma signals, while a measurement with only a gamma source confirms the presence of gamma events in the expected feature space. These results motivate the development of a supervised CNN-based approach to improve neutron/gamma discrimination.Key words: ROSPEC / neutron/ gamma discrimination / proportional counter / CNN / low-energy neutron
Measurements of electroweak production of a photon in association with two jets in proton-proton collisions at 13 TeV
No full textThe first observation of electroweak production of a photon in association with two forward jets in proton-proton collisions is presented. The measurement uses data recorded by the CMS experiment at the LHC during 2016-2018 at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 138 fb. The analysis is performed in a region enriched in photon production via vector boson fusion, with a requirement on the transverse momentum of the photon to exceed 200 GeV. The cross section is measured to be 202 fb, at a significance with respect to the null hypothesis that exceeds five standard deviations. This is in agreement with the standard model prediction of 177 fb. Differential cross sections are measured as a function of various observables. Limits are set on dimension-6 effective field theory operators that contribute to the WW interaction. The observed 95% confidence intervals for the corresponding Warsaw basis Wilson coefficients and are [0.11, 0.16] and [1.6, 1.5], respectively.The first observation of electroweak production of a photon in association with two forward jets in proton-proton collisions is presented. The measurement uses data recorded by the CMS experiment at the LHC during 20162018 at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 138 fb. The analysis is performed in a region enriched in photon production via vector boson fusion, with a requirement on the transverse momentum of the photon to exceed 200 GeV. The cross section is measured to be 202 fb, at a significance with respect to the null hypothesis that exceeds five standard deviations. This is in agreement with the standard model prediction of 177 fb. Differential cross sections are measured as a function of various observables. Limits are set on dimension-6 effective field theory operators that contribute to the WW interaction. The observed 95% confidence intervals for the corresponding Warsaw basis Wilson coefficients and are [0.11, 0.16] and [1.6, 1.5], respectively
Measurement of the top-quark mass using decays with a meson at 13 TeV with the ATLAS detector
No full textThe top-quark mass is measured using top-quark decays producing an isolated lepton and meson reconstructed in its decay mode. The data sample was recorded with the ATLAS detector in proton-proton collisions at a centre-of-mass energy of TeV during Run 2 of the Large Hadron Collider, corresponding to an integrated luminosity of 140 fb. The measurement is based on the invariant mass of the system made of the isolated lepton from the boson decay and the non-isolated pair from a decay of a -hadron, exploiting its sensitivity to the top-quark mass. An unbinned maximum-likelihood fit to the distribution is performed to extract the top-quark mass. The top-quark mass is measured to be GeV, with a total uncertainty of 1.56 GeV. The third uncertainty arises from changing the dipole parton shower gluon-recoil scheme used in top-quark decays.The top-quark mass is measured using top-quark decays producing an isolated lepton and meson reconstructed in its decay mode. The data sample was recorded with the ATLAS detector in proton-proton collisions at a centre-of-mass energy of TeV during Run 2 of the Large Hadron Collider, corresponding to an integrated luminosity of 140 fb. The measurement is based on the invariant mass of the system made of the isolated lepton from the boson decay and the non-isolated pair from a decay of a -hadron, exploiting its sensitivity to the top-quark mass. An unbinned maximum-likelihood fit to the distribution is performed to extract the top-quark mass. The top-quark mass is measured to be GeV, with a total uncertainty of 1.56 GeV. The third uncertainty arises from changing the dipole parton shower gluon-recoil scheme used in top-quark decays
The CMS Barrel Calorimeter Processor near production (BCP V2) board evaluation
No full textThe Barrel Calorimeter Processor (BCP), based on ATCA blade architecture, has been developed for the readout of the electromagnetic calorimeter (ECAL) and hadron calorimeter (HCAL) subdetectors of the CMS experiment. The BCP supports 120 optical receive channels of up to 25 Gbps, 72 optical transmit channels of up to 25 Gbps, an AMD XCVU13P UltraScale+ FPGA, and an embedded AMD Zynq UltraScale+ SoC. The near production BCP V2 is currently undergoing testing. This presentation highlights key testing results, such as high-speed link performance, as well as lessons for the design of the upcoming production BCP V3
9th General Meeting of the LHC EFT Working Group
No full textIn the SMEFT framework, we calculated QCD and EW corrections at NLO to the Higgs decay to a pair. To accurately simulate this process for the LHC, we implemented the matrix element into Sherpa. This allows us to study how the parton shower affects those hard matrix elements
