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Starlight from JWST: Implications for star formation and dark matter models
No full textWe compared the star formation rate in different dark matter (DM) models with UV luminosity data from JWST up to z ≃ 25 and legacy data from HST. We find that a transition from a Salpeter population to top-heavy Pop III stars is likely at z ≃ 10, and that beyond z = 10 − 15 the feedback from supernovae and active galactic nuclei is progressively reduced, so that at z ≃ 25 the production of stars is almost free from any feedback. We compared fuzzy and warm DM models that suppress small-scale structures with the CDM paradigm, and find that the fuzzy DM mass > 5.6 × 10−22 eV and the warm DM mass > 1.5 keV at a 95% CL. The fits of the star formation rate parametrisation do not depend strongly on the DM properties within the allowed range. We find no preference over CDM for enhanced matter perturbations associated with axion mini-clusters or primordial black holes. The scale of the enhancement of the power spectrum should be > 25 Mpc−1 at the 95% CL, excluding axion mini-clusters produced for ma max[105 M⊙/mPBH, 10−4(mPBH/104 M⊙)−0.09] of DM.Key words: cosmology: theory / dark matterWe confront the star formation rate in different dark matter (DM) models with UV luminosity data from JWST up to and legacy data from HST. We find that a transition from a Salpeter population to top-heavy Pop-III stars is likely at and that beyond the feedback from supernovae and active galactic nuclei is progressively reduced, so that at the production of stars is almost free from any feedback. We compare fuzzy and warm DM models that suppress small-scale structures with the CDM paradigm, finding that the fuzzy DM mass and the warm DM mass at the 95% CL. The fits of the star formation rate parametrisation do not depend strongly on the DM properties within the allowed range. We find no preference over CDM for enhanced matter perturbations associated with axion miniclusters or primordial black holes. The scale of the enhancement of the power spectrum should be at the 95% CL, excluding axion miniclusters produced for of DM
Measurements of strangeness production in heavy-ion collisions in the NA61/SHINE experiment
No full textOne of the goals of studying high-energy heavy-ion collisions at facilities such as the Super Proton Synchrotron (SPS), Relativistic Heavy Ion Collider (RHIC), and the Large Hadron Collider (LHC) is to investigate the properties of the quark-gluon plasma (QGP). Particularly, strangeness production in heavy-ion collisions is a longstanding and actively researched topic, offering crucial insights into the properties of strongly interacting matter. This thesis presents a study of strangeness production in heavy-ion collisions, concentrating on baryon production in central Ar+Sc collisions. The data for this analysis was acquired by the NA61/SHINE experiment at CERN. The analysis was performed for three beam momentum values: 40, 75, and 150GeV/ ( 8.77, 11.94, and 17.3~\GeV, respectively). It is the first measurement of baryon production in Ar+Sc collisions in the SPS energy range. baryons are neutral particles, thus, they are typically studied via their charged decay products. In this study, baryons are identified by their weak decay channel with a branching ratio of . The analysis is based on reconstructing the invariant mass of particle pairs considered as potential decay products. The results are corrected for losses due to the geometrical acceptance of the detector, reconstruction inefficiency, applied selections, branching ratio, and feed-down from the decays of heavier hyperons, using detailed Monte Carlo simulation. The quality of the results is confirmed by the dedicated checks, e.g., mean lifetime measurement. The main outcomes of this thesis are the double-differential spectra of baryons produced in central Ar+Sc collisions in rapidity-transverse momentum phase space as well as rapidity spectra and mean multiplicities. The obtained experimental results are compared with particle production models and world data from proton-proton and nucleus-nucleus collisions
BASE - Future Physics Program: From 2025 to 2034 and Beyond
No full textThe BASE collaboration is pushing the frontiers of precision measurements on antimatter systems, with a core mission to rigorously test CPT symmetry and search for physics beyond the Standard Model. Building on a decade of world-leading achievements — including the most precise comparisons of proton and antiproton properties — BASE is now poised for a major evolution. Central to our future strategy is the relocation of the experiment to a dedicated, low-noise offline laboratory at CERN, enabling an order-of-magnitude improvement in measurement precision. Key goals include achieving proton-to-antiproton charge-to-mass ratio comparisons at the parts-per-trillion level, coherent magnetic moment measurements with sub-30 parts-per-trillion uncertainty, and the first ever precision studies of antiprotons outside an accelerator facility. Complementary efforts focus on the development of transportable permanent-magnet antiproton traps, new cooling and detection technologies, and the exploration of antimatter/dark matter interactions. In the far future, BASE aims to pioneer spectroscopy of antihydrogen molecular ions and antideuterons. These plans mark a decisive step toward a globally distributed, highly flexible antimatter research program, advancing our best possible efforts for potential new discoveries in fundamental physics
Identification of tau leptons using a convolutional neural network with domain adaptation in the CMS experiment
No full textThe DeepTau identification algorithm, based on deep neural network techniques, has been developed to reduce the fraction of jets, muons, and electrons misidentified as hadronically decaying tau leptons () in the CMS experiment. The latest version of this algorithm includes domain adaptation by backpropagation, a technique that reduces data-to-simulation discrepancies in the region with the highest purity of genuine candidates. Additionally, a refined training workflow improves classification performance, with a reduction of in the probability for jets to be misidentified as a for a given reconstruction and identification efficiency. This note presents the main novelties introduced to the DeepTau algorithm and evaluates its performance in LHC proton-proton collision data at and collected in 2018 and 2022, respectively, with integrated luminosities of 60 and . The techniques to determine data-to-simulation scale factors are presented with a subset of results among the ones deployed centrally for CMS physics analyses. \textit{This document has been revised with respect to the version dated May 2, 2025.}$
Features of the EAR2 neutron beam following the spallation target upgrade at the n_TOF facility at CERN
No full textThe n_TOF facility at CERN has undergone a major upgrade after the installation of a new spallation target, designed to improve the performance of both neutron beamlines at the experimental areas 1 and 2 (EAR1 and EAR2) and the commissioning of a new experimental area (NEAR). Due to improved coupling of the spallation target with the EAR2 beamline, the upgrade resulted in a significantly increased neutron flux and improved neutron energy resolution. This paper presents the results of the commissioning phase that followed to characterise the EAR2 neutron beamline and validate the FLUKA Monte Carlo simulations of the facility. The main characteristics of the neutron beam, namely the neutron flux, spatial profile and energy resolution, are evaluated and compared to the previous target. The neutron flux presents a general increase of 20% below 1 eV, 40% between 1 eV and 100 keV and 50% between 100 keV and 10 MeV. The measured width of the beam profile was 3 cm full width at half maximum (FWHM) at the reference position for neutron capture measurements. The energy resolution with the new spallation target shows a significant improvement compared to the previous one. Moreover, FLUKA Monte Carlo simulations present a good agreement with the measured neutron flux and profile within uncertainties, and a remarkable reproduction of the energy resolution.The n_TOF facility at CERN has undergone a major upgrade after the installation of a new spallation target, designed to improve the features of both neutron beamlines at the experimental areas 1 and 2 (EAR1 and EAR2) and the commissioning of a new experimental area (NEAR). Due to improved coupling of the spallation target with the EAR2 beamline, the upgrade resulted in a significantly increased neutron flux and improved neutron energy resolution. This paper presents the results of the commissioning phase that followed to characterise the EAR2 neutron beamline and validate the FLUKA Monte Carlo simulations of the facility. The main features of the neutron beam, namely the neutron flux, spatial profile and energy resolution, are evaluated and compared to the previous target. The neutron flux presents a general increase of 20% below 1 eV, 40% between 1 eV and 100 keV and 50% between 100 keV and 10 MeV. The measured width of the beam profile was 3 cm (FWHM) at the reference position for neutron capture measurements. The energy resolution with the new spallation target shows a significant improvement compared to the previous one. Moreover, FLUKA Monte Carlo simulations present a good agreement with the measured neutron flux and profile within uncertainties, and a remarkable reproduction of the energy resolution
Final Steps Towards Production of the ITk Pixel Detector for the ATLAS High Luminosity Upgrade
No full textThe Large Hadron Collider (LHC) upgrade to the High-Luminosity LHC (HL-LHC) will bring an unprecedentedly challenging environment to the detectors, with an instantaneous luminosity of , which corresponds to approximately 140 inelastic proton-proton collisions per bunch crossing. Therefore, in the ATLAS detector upgrade for the HL-LHC, the current Inner Detector will be replaced with an all-silicon Inner Tracker (ITk), to operate under the higher occupancy and radiation damage. The ITk pixel detector is the innermost part of the ITk. It will be equipped with pixel modules consisting of pixel sensors and front-end chips implemented in 65nm CMOS technology. The ITk project is currently in the pre-production stage. To ensure that the quality of the production components will meet the ITk specifications, practise the production workflow, and provide modules for larger scale tests, various steps are exercised in the module pre-production process. Sensors and test structures from different vendors were sent to ITk collaborating institutes for quality assurance (QA), irradiation, and follow-up testing. Test-beam campaigns were conducted to evaluate the performance of sensors in fully-assembled modules in particle beam. To guarantee smooth and uniform production of modules, all ITk institutes are required to demonstrate their ability of fulfilling their responsibilities by going through a Site Qualification. For module assembly, the ITk Pixel Quad Assembly Tooling V2 was developed, reviewed and produced. Module production involves module assembly, parylene coating for high voltage protection, mechanical wire-bond protection, as well as full electrical quality control (QC) tests. This thesis presents the characterisation of the pre-production planar sensors for the ITk pixel detector. The results are within specifications, except for the leakage current stability from one vendor. In test-beam studies, hit detection efficiency of un-irradiated planar sensors in quad modules was measured. The Site Qualification procedure and requirements are introduced. For module assembly, the performance of the tooling was demonstrated, and 16 modules were assembled. QC tests were performed on three assembled modules. In addition to the work related to the ITk pixel detector, a small project on flavour tagging within the scope of this thesis is introduced
Indico Workshop 2025
No full textAbout MITP
- About the Mainz Institute for Theoretical Physics
Short Story about MITP & Indico: The Beginning
- How we discovered Indico
The Daily Work at MITP Guest Relation Office and Management with Indico
- How we work with Indico, which tools we use and what we learned
How the Indico Community has already benefited the MITP
- Story about how we found the community
- The realization: “There are no stupid questions.”
Some thoughts on the future use of Indico from former hotel and tourism employees
- Printing survey results
- Browsing through registrations
- Download room lists
- Assign registrants to rooms
- Printing room lists
I would like to emphasise the talk with a PowerPoint presentation