Constraining the formation mechanisms of light (anti)nuclei at the LHC and applications for cosmic ray physics

The formation mechanism of light (anti)nuclei produced in highenergy hadronic collisions is an open question that is being addressed both theoretically and experimentally. Moreover, the study of (anti)nuclei production at particle accelerators is relevant to model the flux of antinuclei produced in cosmic ray interactions, which represents the dominant background for dark matter searches. According to the most accredited theoretical models, dark matter particles in the galactic halo could annihilate and produce ordinary matter-antimatter pairs. Thanks to its excellent particle identification capabilities, ALICE measured (anti)nuclei in all the collision systems and energies provided by the LHC. Measurements of transverse momentum distributions, ratios of integrated yields, and coalescence probabilities are discussed in these proceedings in comparison with two phenomenological models used to describe the production of nuclei. The performance of the upgraded ALICE detector during the proton proton data taking in Run 3 is discussed together with perspectives on new applications to indirect dark matter searches by the AMS experiment

Employing approximate symmetries for hidden pole extraction

Recent lattice analyses of the Dπ scattering by Hadron Spectrum Collaboration (HadSpec) report only one pole in the D∗0 channel. This is in odds with the unitarised chiral perturbation theory analyses, which predict the D∗0 (2300) as the interplay of two poles. We provide an explanation for this contradiction—the existence of a hidden pole. We further show that the hidden pole can be better extracted from the lattice data by imposing SU(3) flavour constraints on the fitting amplitudes

Pion-nucleon σ term by the pion deep bound states

The pion deep bound states are one of the most important systems to deduce the pion properties in nuclear medium. The pion-nucleon σ term can be determined, in principle, in the bound states by observing the modification of the pion properties at finite density. We investigate the possibility to determine the value of the pion-nucleon σ term precisely by the experimental observables of the deeply bound pionic atoms. We discuss the sensitivity of the observables to the σ term, and find that the gap of the binding energies and the width of the deep bound states are good quantities for the σ term determination

Preface

Abstract not availabl

Study of the pygmy dipole resonance using neutron inelastic scattering at GANIL-SPIRAL2/NFS

The pygmy dipole resonance (PDR) has been the subject of numer- ous studies, both experimental and theoretical. Indeed, the study of the PDR has been and still is of great interest since it allows to constrain the symmetry energy, an important ingredient of the equation of state of nuclear matter that describes the matter within neutron stars. Moreover, the PDR is predicted to play a key role in the r-process via the increase of the neutron capture rate. However, despite numerous experiments dedicated to the study of the PDR, a consistent description is still missing. In this context, we have proposed to study the PDR using a new probe: the neutron inelastic scattering reaction (n,n’γ). An experiment to study the pygmy resonance in 140Ce using the (n,n’γ) reaction has been performed in Septem- ber 2022. This experiment has been made possible thanks to the high-intensity proton beam of the new accelerator SPIRAL2 at GANIL and the NFS (Neutron For Science) facility. The experimental setup was composed of the new generation multi-detectors PARIS, for the detection of γ-rays coming from the de-excitation of the PDR, and MONSTER, for the detection of scattered neutrons. In this article, the experiment motivation and description are presented

Mechanical design of the interaction region of the Future Circular Collider e+e− and support structural optimization

We describe the vacuum chamber of the Future Circular Collider e+ e− interaction region, the conceptual design of the bellows and the lightweight structure called Support Tube. We also present a study on the structural optimization of the support structure. The aim is to optimize the structure to reduce the mass, maintaining the stiffness needed. Finite element analysis is used to develop a detailed numerical model considering complex geometries, material properties, and loading conditions. The study seeks to identify design improvements using optimization algorithms, such as Solid Isotropic Material with Penalization, Generative Design and Lattice approach

Anomaly Detection search for new resonances decaying into a Higgs boson and a generic new particle X in hadronic final states using s√=13 TeV pp collisions with the ATLAS detector

A search is presented for heavy resonances decaying into a Higgs boson (H) and a new particle (X) in a fully hadronic final state with the ATLAS detector at the CERN Large Hadron Collider (LHC) (ATLAS Collaboration, JINST, 3 (2008) S08003). The full Run II of LHC is analyzed, corresponding to an integrated luminosity of 139 fb−1. A novel discovery signal region is imple- mented based on a jet-level anomaly score for signal model-independent tagging of the boosted X boson, representing the first application of fully unsupervised machine learning to an ATLAS analysis. No significant deviation from the SM is observed, so the results are interpreted in upper limits at 95% of confidence level (C.L.) on the production cross section σ(pp → Y → XH) (ATLAS Collaboration, Phys. Rev. D, 108 (2023) 052009)

Searches for Anomalies in hadronic final states with GNNs in ATLAS

Graph neural networks are a promising technique for Anomaly Detection whenever it is possible to express detector information in the form of a graph. In our approach, graphs can be used to represent heavy resonance boson jets as interconnected topocluster nodes. By leveraging graph information and message passing, the network can identify unexpected signals deviating from the Standard Model

Mass spectrum of three-quark and five-quark singly heavy baryons from a chiral model

We construct a chiral effective model for three-quark and five-quark singly heavy baryons (SHBs) which is heavy-quark spin singlet, focusing on the U(1)A axial anomaly effects. Based on the model, we find that the anomaly effects induce the inverse mass hierarchy of negative-parity three-quark SHBs, where Λc becomes heavier than Ξc. On the contrary, the anomaly effect is found to provide no effects for the mass spectrum of five-quark SHBs. We also present a predicted mass spectrum of the SHBs in the presence of the mixing between three-quark and five-quark states. The predicted five-quark dominant Λc(−), whose mass is approximately 2700 MeV, is expected to be a useful evidence to check our description

Study of central exclusive production processes by proton-proton collisions at s√=13 TeV with the CMS experiment

In this paper the reader is introduced to the physics of central exclusive production (CEP) processes. Furthermore, an overview of many CEP processes studied with the CMS experiment during Run2 will be given, including tt- , e-e+, u-u+ and TT central exclusive production