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Search for b hadron decays to long-lived particles in the CMS endcap muon detectors
No full textInternational audienceA search for long-lived particles originating from the decay of b hadrons produced in proton-proton collisions with a center-of-mass energy of 13 TeV at the LHC is presented. The analysis is performed on a data set recorded in 2018, corresponding to an integrated luminosity of 41.6 fb. Interactions of the long-lived particles in the CMS endcap muon system would create hadronic or electromagnetic showers, producing clusters of detector hits. Selected events contain at least one such high-multiplicity cluster in the muon endcaps and require the presence of a displaced muon. The most stringent upper limits to date on the branching fraction (B K), where the long-lived particle decays to a pair of hadrons, are obtained for masses of 0.33.0 GeV and mean proper decay lengths in the range of 1500 cm
Flow in small systems in the EPOS4 approach for high-energy scatterings
No full textInternational audienceEPOS4 is based on a sophisticated (recently significantly improved) parallel-primary-scattering scenario followed by a hydrodynamic expansion, for all collision systems, from small ones such as proton-proton () to big ones such as lead-lead (PbPb). Having already reported on identified particle spectra in recent publications (providing information about radial flow), I discuss here the multiplicity dependence of multi-particle cumulants and flow harmonics, to better understand collectivity in small systems. The model is not particularly tuned for flow results, but it is a "general purpose" approach, trying to accommodate various types of observables with the same model
Gamma rays as leptonic portals to energetic neutrinos: a new Monte Carlo approach
No full textInternational audienceHigh center-of-mass electromagnetic~(EM) interactions could produce decaying heavy leptons and hadrons, leading to neutrino generation. These processes might occur in the most extreme astrophysical scenarios, potentially altering the expected gamma-ray and neutrino fluxes in both the hadronic and the leptonic pictures. For instance, neutrinos could arise from high-redshift EM cascades, triggered by gamma rays beyond scattering background photons, from radio to ultraviolet energy bands. Such energetic gamma rays are predicted in cosmogenic models and in scenarios involving non-standard physics. On astrophysical scales, leptonic production of neutrinos could take place in active galactic nuclei cores, where several-TeV gamma rays interact with the X-ray photons from the hot corona. We explore these scenarios within the CRPropa Monte Carlo code framework, developing dedicated tools to account for leptonic production and decay of heavy leptons and hadrons. In particular, the latter are performed by interfacing with the PYTHIA event generator. With these novel tools, we characterise the spectrum and flavour composition of neutrinos emerging from cosmological EM cascades and from leptonic processes in the core of active galactic nuclei. Finally, we investigate the leptonic production of neutrinos in the context of the IceCube detection of NGC~1068
Muon tracking in a LiquidO opaque scintillator detector
No full textInternational audienceLiquidO is an innovative radiation detector concept. The core idea is to exploit stochastic light confinement in a highly scattering medium to self-segment the detector volume. In this paper, we demonstrate event-by-event muon tracking in a LiquidO opaque scintillator detector prototype. The detector consists of a 30 mm cubic scintillator volume instrumented with 64 wavelength-shifting fibres arranged in an 88 grid with a 3.2 mm pitch and read out by silicon photomultipliers. A wax-based opaque scintillator with a scattering length of approximately 0.5 mm is used. The tracking performance of this LiquidO detector is characterised with cosmic-ray muons and the position resolution is demonstrated to be 450 m per row of fibres. These results highlight the potential of LiquidO opaque scintillator detectors to achieve fine spatial resolution, enabling precise particle tracking and imaging
Décoloniser notre rapport aux animaux: Comment repenser notre relation aux êtres vivants
No full textInternational audienceEt si la véritable question n’était pas : « Faut-il (ou non) manger des animaux ? » mais : « Pourquoi les exploitons-nous ? »Depuis des siècles, la pensée occidentale a hissé l’humain au sommet : maître de la Nature et du vivant, des territoires et des destins animaux. Cette colonisation du vivant a façonné nos lois, nos fermes, nos laboratoires, nos récits, jusqu’à nos gestes les plus ordinaires.Pourtant, d’autres peuples voient le monde autrement. Ils savent que la Terre n’appartient à personne, que l’animal n’est pas seulement une ressource, mais d’abord une présence, une relation, une existence sensible et que nous devons composer avec lui parce que nous vivons avec lui.Dans cet essai, Cédric Sueur explore les racines de cette domination et propose une révolution du regard : décoloniser notre rapport au vivant. Décoloniser les animaux, c’est apprendre à les voir autrement : non plus comme des objets d’usage, mais comme des partenaires de monde. C’est reconnaître la conscience, la mémoire, la joie et la souffrance de celles et ceux avec qui nous partageons la Terre.Un essai engagé et lumineux qui invite à réparer nos imaginaires et à refonder nos pratiques, pour rappeler cette évidence simple : Nous faisons monde ensemble, avec les animaux et avec les autres êtres vivants.Cédric Sueur est professeur en éthologie et en primatologie à l’université de Strasbourg, membre de l’Institut universitaire de France, spécialiste de la socialité chez les animaux et les humains. Il a publié Les Péripéties d’un primatologue
Combination of searches for nonresonant Higgs boson pair production in proton-proton collisions at = 13 TeV
No full textInternational audienceThis paper presents a combination of searches for the nonresonant production of Higgs boson pairs (HH) in proton-proton collisions at a centre-of-mass energy of 13 TeV. The data set was collected by the CMS experiment at the LHC from 2016 to 2018 and corresponds to a total integrated luminosity of 138 fb. The observed (expected) upper limit on the inclusive HH production cross section relative to the standard model (SM) prediction is found to be 3.5 (2.5). Assuming all other Higgs boson couplings are equal to their SM values, the Higgs boson trilinear self-coupling modifier is constrained in the range 1.35 6.37 at 95% confidence level. Similarly, for the coupling modifier , which governs the interaction between two vector bosons and two Higgs bosons, we have excluded = 0 at more than 5 standard deviations for all values of . At 95% confidence level assuming other couplings are equal to their SM values, is constrained in the range 0.64 1.40. This work also studies HH production in several new physics scenarios, using the Higgs effective field theory (HEFT) framework. The HEFT framework is further exploited to study various ultraviolet complete models with an extended Higgs sector and set constraints on specific parameters. An extrapolation of the results to the integrated luminosity expected after the high-luminosity upgrade of the LHC is reported as well
Clustering of dosimetric profiles reveals distinct local control probabilities after SABR in oligometastatic head and neck cancer: insights from the OMET phase II trial quality assurance Process
No full textInternational audienceBackground: Stereotactic ablative radiotherapy (SABR) is increasingly used in the management of oligometastatic disease. However, variability in SABR plans raises questions about their impact on local control at SABR-treated lesions (LC). We aimed to explore whether quantitative dosimetric parameters could predict LC in head and neck squamous cell carcinoma (HNSCC) patients in the OMET (GORTEC 2014-04) trial. Methods: OMET is a multicentre randomized phase II trial comparing SABR-alone versus chemo-SABR in patients with <= 3 PET-confirmed oligometastases. A post-hoc analysis of all irradiated lesions (N = 98) from 69 patients was performed. Twenty spatial and dosimetric indices, together with conventional metrics including Dmin, Dmean, Dmax, total target volume and homogeneity/conformity indices, were extracted from the DICOM files. Hierarchical clustering was used to identify phenotypes of plan quality. Kaplan-Meier analyses evaluated associations with LC. Results: Wide inter-patient variability in dosimetric parameters and three clusters was observed, despite SABR standardization per trial protocol. The cluster of lesions (N = 13) with high intra-tumoral dose heterogeneity and non-optimal conformity was associated with significantly improved LC. In contrast, a more homogeneous and conformal phenotype was linked to inferior LC (N = 14). The largest cluster (N = 69) showed no clearly distinctive pattern and had intermediate LC. Conclusions: In SABR for oligometastatic HNSCC, intra-tumoral dose heterogeneity may be more predictive of LC than strict conformity, particularly in high-dose per fraction regimens. A quantitative, phenotype-based machine learning approach using unsupervised clustering of composite dosimetric metrics may be explored further within SABR quality assurance frameworks beyond binary expert review alone
Clinical White Paper From the “Hadrontherapy for Life” Symposium–Clinical Expansion of Carbon Ion Facilities Worldwide
No full textInternational audienceBackgroundCarbon ion radiotherapy (CIRT) combines the physical precision of charged particles with high-linear energy transfer (LET) biological effectiveness, enabling superior control of radioresistant or anatomically complex tumors. Initially developed in Japan, CIRT is slowly expanding globally with increasing institutional and clinical maturity.ObjectiveTo summarize current clinical evidence, operational strategies, and expansion plans for carbon ion facilities worldwide, as discussed during the “Hadrontherapy-for-Life” symposium held in Caen, France (March 2025).MethodsThis white paper compiles presentations and institutional reports from major CIRT centers in Japan (QST, Gunma), Europe (HIT, CNAO, MedAustron, Cyclhad), and other emerging sites. Data sources include institutional registries, peer-reviewed studies, and national frameworks for hadrontherapy development.ResultsOver 50,000 patients have received CIRT worldwide. Japan remains the leading contributor through the J-CROS network, emphasizing registry-based research, hypofractionation, and treatment of mobile tumors. European centers adopt translational programs aimed at further exploiting biological properties of carbon and helium ions. Major barriers include heterogeneous dose-modeling (local effect model vs modified microdosimetric kinetic model), limited image guidance, lack of standardized indications, and funding disparities. Ongoing efforts emphasize registry harmonization, pragmatic trials, and cost-effectiveness modeling. New multi-ion facilities such as Cyclhad (Caen) aim to propose multi-ion therapy, increase the level of evidence for clinical use, and promote research.ConclusionsCIRT is transitioning from pioneering programs to a coordinated global network. Collaborative initiatives and shared data platforms are essential to establish evidence-based indications, optimize biological modeling, and ensure economic sustainability. The “Hadrontherapy-for-Life” initiative calls for a strategic step toward internationally standardized, clinically integrated heavy-ion therapy
Towards precision cosmology with Voids x CMB correlations (I): Roman-Agora mock catalogs and pipeline validation
No full textInternational audienceWe construct and validate a set of multi-purpose mock galaxy catalogs designed to capture, to different degrees of accuracy, the main characteristics of the Nancy Grace Roman Space Telescope survey. These catalogs provide a foundation for void statistics and various CMB cross-correlation analyses. Our approach differs from traditional halo occupation or abundance matching methods by directly translating a reference mock catalog -- containing basic properties of the host halos -- into a new simulation (in our case Agora). This technique, which we call analog matching, assigns a halo counterpart in the new simulation to each reference galaxy through a nearest-neighbor search in a multi-dimensional parameter space. This space can include halo mass, environmental measures and other galaxy-specific attributes. By varying the composition of this parameter vector, we can generate catalogs of differing complexity and conduct systematic tests to examine the influence of modelling choices on LSS statistics. We find that analog matching based on halo mass alone, or halo mass and galaxy-type indicators, successfully reproduces the expected Roman emission-line galaxy statistics. We also show that reproducing two-dimensional galaxy clustering does not guarantee consistent void properties. Our results highlight the importance of matching void statistics for improved mock accuracy, and demonstrate that measuring voids provides independent and sensitive constraints on galaxy-halo connections beyond the matter power spectrum. An important by-product of our setup is that it is fully general and can be applied to any combination of simulation and reference catalog, provided that the desired parameter space for both is specified. The resulting Roman-Agora mock catalogs offer a versatile resource for LSS x CMB studies and a benchmark for assessing the impact of mock accuracy on cosmological observables
Modeling Ultra-High-Energy Cosmic Rays propagation using the input from Configuration Interaction Shell Model
No full textInternational audienceThe dipole response of a nuclear system, characterized by its photon strength function (PSF), is a key ingredient of many applications of nuclear structure, ranging from nuclear reactor design and nuclear waste transmutation to astrophysical models of nucleosynthesis and stellar evolution. While the majority of those applications require the knowledge of PSF of mid-mass and heavy nuclei, there is now renewed interest in strength distributions of light nuclei in the framework of the PANDORA project, which aims at an understanding of the mass distribution of ultrahigh-energy cosmic radiation (UHECR).UHECR is of extragalactic origin and its interaction along the travel path is dominated by photoabsorption of cosmic background radiation boosted to the Giant Dipole Resonance (GDR) energy region in the center-of-mass system. Thus, systematic knowledge of the photoabsorption cross sections in light nuclei and of their subsequent particle decay is required. The purpose of this work is to enhance the database of available theoretical evaluations of PSF of light nuclei that are necessary in the studies of UHECR propagation. We employ the Configuration Interaction Shell Model (CI-SM) approach to provide predictions of dipole response for and -shell nuclei, with mass number between 7 and 40. Theoretical predictions are compared to available data and to existing predictions from phenomenological and microscopic models. Finally, the impact of using of CI-SM PSF on the predicted propagation of a Ca UHECR source is studied