International Linear Collider
Not a member yet
509047 research outputs found
Sort by
On quivers, spectral networks and black holes
No full textIt was recently found that connection coefficients of the Heun equation can be derived in closed form using crossing symmetry in two-dimensional Liouville theory via the Nekrasov-Shatashvili functions. In this work, we systematize this approach to second-order linear ODEs of Fuchsian type, which arise in the description of N = 2, four-dimensional quiver gauge theories. After presenting the general procedure, we focus on the specific case of Fuchsian equations with five regular singularities and present some applications to black hole perturbation theory. First, we consider a massive scalar perturbation of the Schwarzschild black hole in AdS7. Next, we analyze vector type perturbations of the Reissner-Nordström-AdS5 black hole. We also discuss the implications of our results in the context of the AdS/CFT correspondence and present explicit results in the large spin limit, where we make connection with the light-cone bootstrap. Furthermore, using the spectral network technology, we identify the region of the moduli space in Seiberg-Witten theory that is relevant for the study of black hole quasinormal modes. Our results suggest that, in some cases, this region corresponds to the strong-coupling regime, highlighting the potential applicability of the conformal GMN TBA framework to address scenarios where the gravitational dictionary implies that the instanton counting parameters are not parametrically small
Proof of principle for a light dark matter search with low-energy positron beams at NA64
No full textThermal light dark matter (LDM) with particle masses in the 1 MeV - 1 GeV range could successfully explain the observed dark matter abundance as a relic from the primordial Universe. In this picture, a new feeble interaction acts as a "portal" between the Standard Model and LDM particles, allowing for the exploration of this paradigm at accelerator experiments. In the last years, the "missing energy" experiment NA64e at CERN SPS (Super Proton Synchrotron) has set world-leading constraints in the vector-mediated LDM parameter space, by exploiting a 100 GeV electron beam impinging on an electromagnetic calorimeter, acting as an active target. In this paper, we report a detailed description of the analysis of a preliminary measurement with a 70 GeV positron beam at NA64e, performed during summer 2023 with an accumulated statistic of 1.6 x 10^10 positrons on target. This data set was analyzed with the primary aim of evaluating the performance of the NA64e detector with a lower energy positron beam, towards the realization of the post-LS3 program. The analysis results, other than additionally probing unexplored regions in the LDM parameter space, provide valuable information towards the future NA64e positron campaign
Search for bosons of an extended Higgs sector in b quark final states in proton-proton collisions at 13 TeV
No full textA search for beyond-the-standard-model neutral Higgs bosons in final states with bottom quarks is performed with the CMS detector. The data were recorded in proton-proton collisions at a centre-of-mass energy of 13 TeV at the CERN LHC and correspond to an integrated luminosity of 36.7-126.9 fb, depending on the probed mass range. No signal above the standard model background expectation is observed. Upper limits on the production cross section times branching fraction are set for Higgs bosons in the mass range of 125-1800 GeV. The results are interpreted in benchmark scenarios of the minimal supersymmetric standard model, as well as suitable classes of two-Higgs-doublet models.A search for beyond-the-standard-model neutral Higgs bosons in final states with bottom quarks is performed with the CMS detector. The data were recorded in proton-proton collisions at a centre-of-mass energy of 13 TeV at the CERN LHC, and correspond to an integrated luminosity of 36.7-126.9 fb depending on the probed mass range. No signal above the standard model background expectation is observed. Upper limits on the production cross section times branching fraction are set for Higgs bosons in the mass range of 125-1800 GeV. The results are interpreted in benchmark scenarios of the minimal supersymmetric standard model, as well as suitable classes of two-Higgs-doublet models
Operating the 200 Gbps IRIS-HEP Demonstrator for ATLAS
No full textThe ATLAS experiment is currently developing columnar analysis frameworks which leverage the Python data science ecosystem. We describe the construction and operation of the infrastructure necessary to support demonstrations of these frameworks, with a focus on those from IRIS-HEP. One such demonstrator aims to process the compact ATLAS data format PHYSLITE at rates exceeding 200 Gbps. Various access configurations and setups on different sites are explored, including direct access to a dCache storage system via Xrootd, the use of ServiceX, and the use of multiple XCache servers equipped with NVMe storage devices. Integral to this study was the analysis of network traffic and bottlenecks, worker node scheduling and disk configurations, and the performance of an S3 object store. The system's overall performance was measured as the number of processing cores scaled to over 2,000 and the volume of data accessed in an interactive session approached 200 TB. The presentation will delve into the operational details and findings related to the physical infrastructure that underpins these demonstrators
Visite de Madame Isabelle Arrighi, Sous-Préfète de Saint-Julien-en-Genevois, France
No full textVisite de Madame Isabelle Arrighi, Sous-Préfète de Saint-Julien-en-Genevois, République français
International Conference on Quantum Technologies for High-Energy Physics
No full textIn this work, we study a Quantum Generative Model based on the Quantum Chebyshev Transform that enables to learn and sampling probability distributions. The model is applied to fragmentation functions, which quantify the probability that a given parton decays into a particular hadron after a hard scattering event. The results show that this model enables an efficient sampling, performing a natural quantum interpolation when the sampling is executed on an extended register, a task that might be challenging to perform classically. Furthermore, we investigate the model's performance when correlations between the momentum fraction and the energy scale are introduced via entanglement in quantum circuits. This study provides valuable insights into the correlations of these two variable
Observation of hyperon local polarization in pPb collisions at 8.16 TeV
No full textThe polarization of the and hyperons along the beam direction has been measured in proton-lead (pPb) collisions at a center-of-mass energy per nucleon pair of 8.16 TeV. The data were obtained with the CMS detector at the LHC and correspond to an integrated luminosity of 186.0 6.5 nb. A significant azimuthal dependence of the hyperon polarization, characterized by the second-order Fourier sine coefficient , is observed. The values decrease as a function of charged particle multiplicity, but increase with transverse momentum. A hydrodynamic model that describes the observed values in nucleus-nucleus collisions by introducing vorticity effects does not reproduce either the sign or the magnitude of the pPb results. These observations pose a challenge to the current theoretical implementation of spin polarization in heavy ion collisions and offer new insights into the origin of spin polarization in hadronic collisions at LHC energies.The polarization of the and hyperons along the beam direction has been measured in proton-lead (pPb) collisions at a center-of-mass energy per nucleon pair of 8.16 TeV. The data were obtained with the CMS detector at the LHC and correspond to an integrated luminosity of 186.0 6.5 nb. A significant azimuthal dependence of the hyperon polarization, characterized by the second-order Fourier sine coefficient , is observed. The values decrease as a function of charged particle multiplicity, but increase with transverse momentum. A hydrodynamic model that describes the observed values in nucleus-nucleus collisions by introducing vorticity effects does not reproduce either the sign or the magnitude of the pPb results. These observations pose a challenge to the current theoretical implementation of spin polarization in heavy ion collisions and offer new insights into the origin of spin polarization in hadronic collisions at LHC energies
ATLAS software tools to handle ROOT RNTuple
No full textThe software of the ATLAS experiment at the CERN LHC accelerator contains a number of tools to inspect (validate, summarize, peek into etc.) all its official data formats recorded in ROOT files. These tools --- mainly written in the Python programming language --- handle the ROOT TTree which is currently the main storage object format of ROOT files. However, the ROOT project has developed an alternative to TTree, called RNTuple. The new storage format offers significant improvements and ATLAS plans to adopt it in LHC Run 4. Work is ongoing to enhance the tools in order to handle the RNTuple storage format in addition to TTree in a transparent for the user way. The work is aided by modern and detailed APIs provided by RNTuple. We will present the progress made and lessons learnt