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The forthcoming Electron--Ion Collider (EIC), which is expected to commence operations in the early 2030s, has already reached several significant milestones on its path toward completion. The core of the EIC physics program is the 3D imaging of partonic structures in protons and nuclei. The experimental detector setup required to enable this primary objective utilizes "far-forward" (FF) and "far-backward" (FB) detectors positioned downstream in the hadron-going and electron-going directions, respectively, from the interaction point of the EIC. The primary purpose of the FB detectors is to monitor luminosity and measure scattered electrons in collisions in the EIC, while the array of FF detectors is used to tag and reconstruct both charged and neutral particles that scatter at small angles. These detectors also enable a broader physics program than was initially envisioned, enhancing the EIC's research potential. The expanded capabilities have been a prime focus for engaging the broader nuclear physics community to build a robust groundwork for the EIC. In these proceedings, we will describe the FF/FB detectors and review the advanced forward physics program facilitated by them at the EIC., Comment: 6 pages, 2 figures, proceedings of the XXXI International Workshop on Deep Inelastic Scattering and Related Subjects (DIS2024)

The European Committee for Future Accelerators (ECFA) Early-Career Researcher (ECR) panel, which represents the interests of the ECR community to ECFA, presents in this document its initiatives and activities in the year 2023. This report summarises the process of the first big turnover in the panel composition at the start of 2023 and reports on the activities of the active working groups - either pursued from before or newly established. The overarching goal of the ECFA-ECR panel is to better understand and support the diverse interests of early-career researchers in the ECFA community and beyond., Comment: Editors: Jan-Hendrik Arling, Cecilia Borca, Armin Ilg, Arnau Morancho Tarda, Holly Pacey, Marko Pesut, Elisabetta Spadaro Norella and Marta Urbaniak. arXiv admin note: substantial text overlap with arXiv:2212.11238

The High-Luminosity Large Hadron Collider (HL-LHC) is designed to achieve higher instantaneous luminosities, enabling the exploration of the rarest processes of the Standard Model (SM). The CMS collaboration has published an Expression of Interest to pursue the study of the central exclusive production processes, using near-beam detectors. This report details both the expected performance and the scientific potential of the CMS near-beam proton spectrometer at the HL-LHC., Comment: 3 pages, 1 table, proceedings of the The Eleventh Annual Conference on Large Hadron Collider Physics (LHCP2023)

The study of hadronic showers, which are produced by cosmic rays penetrating the Earth's atmosphere, is essential for shedding light on the origins and characteristics of high-energy particles originating from space and reaching our planet. At the Large Hadron Collider at CERN, there are plans to conduct a short run of proton--oxygen collisions in 2025 to refine the modeling of hadronic showers. This work explores the potential impact on constraining models of hadronic showers by measuring interactions facilitated by color-neutral objects such as photons, pomerons, and pions. These interactions are often characterized by high-energy protons or neutrons produced at forward rapidities and can be tagged using dedicated forward proton and neutron detectors., Comment: 4 pages, 5 figures, proceedings of the XVIII International Conference on Topics in Astroparticle and Underground Physics (TAUP 2023)

The top quark plays a central role in particle physics, as many experiments at the Large Hadron Collider scrutinize its properties within the Standard Model. Although most of the measurements of the top quarks today concentrate on production modes initiated by quarks or gluons, this review will highlight the lesser-explored modes initiated by pomerons or photons. It aims to provide an in-depth look into both the phenomenological studies and the existing experimental measurements, emphasizing the necessity of exploring the diffractive and photon-induced production of top quarks to enhance the accuracy of top-quark measurements., Comment: Review, submitted to MDPI Universe. 15 pages, 11 figures, 1 table

A short run of proton-oxygen and oxygen-oxygen collisions is planned to take place at the Large Hadron Collider during LHC Run 3. The primary goal of this run is to improve the modeling of Cosmic-Ray interactions and to reduce the uncertainties associated with proton-Air cross-sections. While the inelastic cross-section will be measured directly, an array of very forward proton and neutron detectors introduced by the ATLAS and CMS experiments can allow going beyond the current physics research proposal, providing a unique opportunity to study elastic and diffractive interactions in pO collisions at the center of mass energies above TeV. This article presents the possible impact of proton and neutron tagging on the measurement of the elastic and diffractive components, as well as discusses the prospects of measuring the decay products of oxygen ions., Comment: Proceedings of the 38th International Cosmic Ray Conference (ICRC2023)

The European Committee for Future Accelerators (ECFA) Early Career Researcher's (ECR) panel, which represents the interests of the ECR community to ECFA, officially began its activities in January 2021. In the first two years, the panel has defined its own internal structure, responded to ECFA requests for feedback, and launched its own initiatives to better understand and support the diverse interests of early career researchers. This report summarises the panel composition and structure, as well as the different activities the panel has been involved with during the first two years of its existence., Comment: Editors: Jan-Hendrik Arling, Emanuele Bagnaschi, Xabier Cid Vidal, Katherine Dunne, Viktoria Hinger, Armin Ilg, Henning Kirschenmann, Steven Schramm, Pawe{\l} Sznajder, Sarah Williams, Valentina Zaccolo

The Large Hadron Collider (LHC) at CERN has generated in the last decade an unprecedented volume of data for the High-Energy Physics (HEP) field. Scientific collaborations interested in analysing such data very often require computing power beyond a single machine. This issue has been tackled traditionally by running analyses in distributed environments using stateful, managed batch computing systems. While this approach has been effective so far, current estimates for future computing needs of the field present large scaling challenges. Such a managed approach may not be the only viable way to tackle them and an interesting alternative could be provided by serverless architectures, to enable an even larger scaling potential. This work describes a novel approach to running real HEP scientific applications through a distributed serverless computing engine. The engine is built upon ROOT, a well-established HEP data analysis software, and distributes its computations to a large pool of concurrent executions on Amazon Web Services Lambda Serverless Platform. Thanks to the developed tool, physicists are able to access datasets stored at CERN (also those that are under restricted access policies) and process it on remote infrastructures outside of their typical environment. The analysis of the serverless functions is monitored at runtime to gather performance metrics, both for data- and computation-intensive workloads., Comment: 10 pages, CCGRID 2022

We study the LHC sensitivity to new broad neutral resonances produced in two-photon fusion and decaying to a top quark pair, $\gamma\gamma \to t\bar{t}$. This is probed in central exclusive $t\bar{t}$ production in proton-proton collisions, $pp \to p t\bar{t} p$. We use the tagging of the intact protons by PPS (CMS) and AFP (ATLAS) and consider the semi-leptonic $t\bar t$ channel. The sensitivity is also mapped onto a set of dimension-8 $\gamma\gamma t\bar{t}$ operators in the large mass limit. Using the kinematical correlations between the intact protons and the reconstructed $t\bar{t}$ system, we obtain a sensitivity to the couplings of the dimension-8 operators of $1.4 \cdot 10^{-11}~\mathrm{GeV}^{-4}$ at 95% CL. The sensitivity to the anomalous couplings is significantly improved down to about $7\cdot 10^{-12}~\mathrm{GeV}^{-4}$ if the proton time-of-flight is known with a precision of 20 ps in future measurements. The 95% CL sensitivity to broad neutral resonances reaches masses of order $ 1500~\mathrm{GeV} $ when using timing information., Comment: 23 pages, 10 figures

The goal of this whitepaper is to give a comprehensive overview of the rich field of forward physics. We discuss the occurrences of BFKL resummation effects in special final states, such as Mueller-Navelet jets, jet gap jets, and heavy quarkonium production. It further addresses TMD factorization at low x and the manifestation of a semi-hard saturation scale in (generalized) TMD PDFs. More theoretical aspects of low x physics, probes of the quark gluon plasma, as well as the possibility to use photon-hadron collisions at the LHC to constrain hadronic structure at low x, and the resulting complementarity between LHC and the EIC are also presented. We also briefly discuss diffraction at colliders as well as the possibility to explore further the electroweak theory in central exclusive events using the LHC as a photon-photon collider., Comment: 77 pages, 27 figures, contribution to Snowmass 2021; contributions updated and authors added

The European Committee for Future Accelerators (ECFA) Early-Career Researchers (ECR) Panel was invited by the ECFA Detector R&D Roadmap conveners to collect feedback from the European ECR community. A working group within the ECFA ECR panel held a Townhall Meeting to get first input, and then designed and broadly circulated a detailed survey to gather feedback from the larger ECR community. A total of 473 responses to this survey were received, providing a useful overview of the experiences of ECRs in instrumentation training and related topics. This report summarises the feedback received, and is intended to serve as an input to the ECFA Detector R&D Roadmap process., Comment: Editors: Jan-Hendrik Arling, Katherine Dunne, Armin Ilg, Adri\'an Irles, Predrag Milenovic, Steven Schramm, Mariana Shopova, and Sarah Williams

This paper introduces a new class of observation driven dynamic models. The time evolving parameters are driven by innovations of copula form. The resulting models can be made strictly stationary and the innovation term is typically chosen to be Gaussian. The innovations are formed by applying a copula approach for the conditional score function which has close connections the existing literature on GAS models. This new method provides a unified framework for observation-driven models allowing the likelihood to be explicitly computed using the prediction decomposition. The approach may be used for multiple lag structures and for multivariate models. Strict stationarity can be easily imposed upon the models making the invariant properties simple to ascertain. This property also has advantages for specifying the initial conditions needed for maximum likelihood estimation. One step and multi-period forecasting is straight-forward and the forecasting density is either in closed form or a simple mixture over a univariate component. The approach is very general and the illustrations focus on volatility models and duration models. We illustrate the performance of the modelling approach for both univariate and multivariate volatility models.

In High Energy Physics experiments Particle Flow (PFlow) algorithms are designed to provide an optimal reconstruction of the nature and kinematic properties of the particles produced within the detector acceptance during collisions. At the heart of PFlow algorithms is the ability to distinguish the calorimeter energy deposits of neutral particles from those of charged particles, using the complementary measurements of charged particle tracking devices, to provide a superior measurement of the particle content and kinematics. In this paper, a computer vision approach to this fundamental aspect of PFlow algorithms, based on calorimeter images, is proposed. A comparative study of the state of the art deep learning techniques is performed. A significantly improved reconstruction of the neutral particle calorimeter energy deposits is obtained in a context of large overlaps with the deposits from charged particles. Calorimeter images with augmented finer granularity are also obtained using super-resolution techniques., Comment: 15 pages, 10 figures. Note to admin : updating to journal version

Physics beyond the Standard Model (BSM) may be unveiled by studying events with a high number of outgoing jets, produced at the LHC with energies above the TeV scale (energetic multi-jet events). Such events are dominated by QCD processes, where the calculations rely on some sort of approximation. Therefore, it is important to develop a robust approach for modeling such events that could probe the existence of BSM signals. In this note, jet spatial distributions in energetic multi-jet processes were compared using several state-of-the-art MC event generators. Slight differences were found, indicating modelling limitations. Therefore, a data-driven technique for the estimation of processes with a final state that contains a large number of jets is proposed. This procedure can predict jet multiplicities up to a precision of ~25\% in energetic multi-jet events., Comment: 12 pages, 7 figures. To appear in EPJC

The pseudo-marginal algorithm is a variant of the Metropolis--Hastings algorithm which samples asymptotically from a probability distribution when it is only possible to estimate unbiasedly an unnormalized version of its density. Practically, one has to trade-off the computational resources used to obtain this estimator against the asymptotic variances of the ergodic averages obtained by the pseudo-marginal algorithm. Recent works optimizing this trade-off rely on some strong assumptions which can cast doubts over their practical relevance. In particular, they all assume that the distribution of the difference between the log-density and its estimate is independent of the parameter value at which it is evaluated. Under regularity conditions we show here that, as the number of data points tends to infinity, a space-rescaled version of the pseudo-marginal chain converges weakly towards another pseudo-marginal chain for which this assumption indeed holds. A study of this limiting chain allows us to provide parameter dimension-dependent guidelines on how to optimally scale a normal random walk proposal and the number of Monte Carlo samples for the pseudo-marginal method in the large-sample regime. This complements and validates currently available results., Comment: 76 pages, 3 figures