Looking forward to test the KOTO anomaly with FASER
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72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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First branching fraction measurement of the suppressed decay Ξ c 0 → π − Λ c +
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72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Search for an Invisibly Decaying Z ′ Boson at Belle II in e + e − → μ + μ − ( e ± μ ∓ ) Plus Missing Energy Final States
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46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
Observation of Two New Excited Ξ b 0 States Decaying to Λ b 0 K − π +
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72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Search for Nuclear Modifications of 𝐵 + Meson Production in 𝑝-Pb Collisions at $\sqrt{𝑠_{NN}}$ = 8.16 TeV
Nuclear medium effects on 𝐵 + meson production are studied using the binary-collision scaled cross section ratio between events of different charged-particle multiplicities from proton-lead collisions. Data, collected by the CMS experiment in 2016 at a nucleon-nucleon center-of-mass energy of $\sqrt{𝑠_{NN}}$ = 8.16 TeV, corresponding to an integrated luminosity of 175 nb −1 , were used. The scaling factors in the ratio are determined using a novel approach based on the 𝑍 → 𝜇 − 𝜇 + cross sections measured in the same events. The scaled ratio for 𝐵 + is consistent with unity for all event multiplicities, putting stringent constraints on nuclear modification for heavy flavor.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Evidence for Similar Collectivity of High Transverse-Momentum Particles in 𝑝-Pb and Pb-Pb Collisions
Charged hadron elliptic anisotropies (𝑣 2 ) are presented over a wide transverse momentum (𝑝 T ) range for proton-lead (𝑝 Pb) and lead-lead (PbPb) collisions at nucleon-nucleon center-of-mass energies of 8.16 and 5.02 TeV, respectively. The data were recorded by the CMS experiment and correspond to integrated luminosities of 186 and 0.607 nb −1 for the 𝑝Pb and PbPb systems, respectively. A four-particle cumulant analysis is performed using subevents separated in pseudorapidity to effectively suppress noncollective effects. At high 𝑝 T (𝑝 T > 8 GeV), significant positive 𝑣 2 values that are similar between 𝑝 Pb and PbPb collisions at comparable charged particle multiplicities are observed. This observation suggests a common origin for the multiparticle collectivity for high-𝑝 T particles in the two systems.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Cross sections of 𝜂 mesons in 𝑝 +𝑝 collisions at forward rapidity at $\sqrt{𝑠}$ = 500 GeV and central rapidity at $\sqrt{𝑠}$ = 510 GeV
We present the first measurements of the forward and midrapidity 𝜂-meson cross sections from 𝑝 + 𝑝 collisions at $\sqrt{𝑠}$ = 500 and 510 GeV, respectively. We also report the midrapidity 𝜂/𝜋 0 ratio at 510 GeV. The forward cross section is measured differentially in 𝜂-meson transverse momentum (𝑝 𝑇 ) from 1.0 to 6.5 GeV/𝑐 for pseudorapidity 3.0 < |𝜂| < 3.8. The midrapidity cross section is measured from 3.5 to 44 GeV/𝑐 for pseudorapidity |𝜂| < 0.35. Both cross sections serve as critical inputs to an updated global analysis of the 𝜂-meson fragmentation functions.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Leveraging on-shell interference to search for FCNCs of the top quark and the Z boson
Abstract Flavour-changing-neutral currents (FCNCs) involving the top quark are highly suppressed within the Standard Model (SM). Hence, any signal in current or planned future collider experiments would constitute a clear manifestation of physics beyond the SM. We propose a novel, interference-based strategy to search for top-quark FCNCs involving the Z boson that has the potential to complement traditional search strategies due to a more favourable luminosity scaling. The strategy leverages on-shell interference between the FCNC and SM decay of the top quark into hadronic final states. We estimate the feasibility of the most promising case of anomalous tZc couplings using Monte Carlo simulations and a simplified detector simulation. We consider the main background processes and discriminate the signal from the background with a deep neural network that is parametrised in the value of the anomalous tZc coupling. We present sensitivity projections for the HL-LHC and the FCC-hh. We find an expected 95% CL upper limit of $${\mathcal {B}}_{\textrm{excl}}(t\rightarrow Zc) = 6.4 \times 10^{-5}$$ B excl ( t → Z c ) = 6.4 × 10 - 5 for the HL-LHC. In general, we conclude that the interference-based approach has the potential to provide both competitive and complementary constraints to traditional multi-lepton searches and other strategies that have been proposed to search for tZc FCNCs.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Proceedings of RIKEN BNL Research Center Workshop: Jet Observables at the Electron-Ion Collider (Volume 136) [Slides]
As the realization of an Electron Ion Collider (EIC) moves forward, efforts from the nuclear physics community continue to grow. In addition to the ongoing detector R&D efforts, plans for novel analysis topics must be demonstrated to aid in the detector designs, so that we can maximize the physics output of the EIC. This relies on input from both the experimental and theory communities. The aim of this workshop is to gather experts as well as those with a developing interest in the EIC so that theorists and experimentalists with experience measuring jets in a variety of hadronic collision systems can discuss the possible advantages and challenges of making measurements of jets in e+p and for the first time ever jets in e+A collisions at the EIC. In the time since the EIC white paper was written in 2011, there has been a growing recognition that jet observables could be a powerful probe of many of the physics topics which will be addressed by the EIC. Recent years have seen a multitude of both theoretical and experimental papers exploring the utility of jets for topics as diverse as determining the hadronic structure of photons, studying the 3D structure of the nucleon, and characterizing the properties of the matter found in nuclei. The aim of this workshop is to provide a forum for both theorists and experimentalists to discuss the possible advantages and challenges of jet measurements in e+p and e+A collisions at the EIC, learn about the status of necessary simulation tools, consider requirements on detector performance, and propose new ideas for jet observables and measurements. This proceedings report is a compilation of slides from the presentations.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Maximizing RHIC Deliverable Luminosity with Dynamic Telescopic Beta* Squeeze
To benefit fully from the exceptional performance of the Relativistic Heavy Ions Collider (RHIC) Stochastic Cooling system during heavy ions physics store, the betatron amplitude β ∗ at a given col lision point (IP) can be squeezed from its design value by using the available space in the quadrupole triplets from smaller beam emittances. This should allow reaching new heights in deliverable lumi nosity for both STAR and PHENIX experiments. Prior to 2014, RHIC lattice designs only squeezed the interaction regions (IR’s) down to β ∗ = 0.70 m. To get past this limitation, one can use a telescopic scheme where the non-experimental insertions surrounding STAR and PHENIX are used to generate and close a β-beat wave contributing to the final squeeze in the two IP’s of interest. The following presents the various steps of the implementation in RHIC of this telescopic scheme and the corresponding changes in collision rates and specific luminosity. A full feasibility study with a review of hardware and beam dynamics limitations is also included.
43 PARTICLE ACCELERATORS↗
A Vertex-Aligned Model for Packing 4-Hexagonal Clusters in a Regular Hexagonal Container
This paper deals with a problem the packing polyhex clusters in a regular hexagonal container. It is a common problem in many applications with various cluster shapes used, but symmetric polyhex is the most useful in engineering due to its geometrical properties. Hence, we concentrate on mathematical modeling in such an application, where using the “bee” tetrahex is chosen for the new Compact Muon Solenoid (CMS) design upgrade, which is one of four detectors used in Large Hadron Collider (LHC) experiment at European Laboratory for Particle Physics (CERN). We start from the existing hexagonal containers with hexagonal cells packed inside, and uniform clustering applied. We compare the center-aligned (CA) and vertex-aligned (VA) models, analyzing cluster rotations providing the increased packing efficiency. We formally describe the geometrical properties of clustering approaches and show that cluster sharing is inevitable at the container border with uniform clustering. In addition, we propose a new vertex-aligned model decreasing the number of shared clusters in the uniform scenario, but with a smaller number of clusters contained inside the container. Also, we describe a non-uniform tetrahex cluster packing scheme in the proposed container model. With the proposed cluster packing solution, it is accomplished that all clusters are contained inside the container region. Since cluster-sharing is completely avoided at the container border, the maximal packing efficiency is obtained compared to the existing models.
97 MATHEMATICS AND COMPUTING↗
VTOL in-ground effect flows for closely spaced jets
The interaction of two vertically impinging incompressible jets is studied through the invention of physical flow models that approximate the behavior of colliding wall jets as the incident jets are brought closer together. The mechanism for upwash formation is studied and momentum models for the upwash sheet are postulated. An approximate method for computing the ground isobar pattern of jet and upwash deflection zones is presented and compared with test data. A method for computing the upwash impingement force in the absence of secondary induced flow effects is also presented and reasonably good agreement is achieved with experimental data for cylindrical fuselage shapes of circular and rectangular cross section.
Siclari, M. J.↗
Design and optimization of higher order mode couplers for the superconducting cavities of the PERLE energy recovery linac
The Powerful Energy Recovery Linac for Experiments (PERLE) is an energy recovery linac (ERL) facility based on superconducting radio-frequency (SRF) technology to be hosted at the Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab) in France. With a target beam power of 10 MW, PERLE aims to demonstrate the high-current, continuous wave, multi-pass operation to validate options for future high-energy machines, such as the 50 GeV ERL proposed for the Large Hadron electron Collider (LHeC) and the Future Circular electron-hadron Collider (FCC-eh), and host dedicated particle physics and nuclear experiments. In high-current ERLs, the regenerative Beam Breakup (BBU), emerging from the beam and cavity Higher Order Modes (HOMs) interaction, is a major concern for their stable operation. Beam-induced HOMs can increase the cavity heat load at cryogenic temperature and cause beam instabilities. HOM couplers are installed in the cavity beam pipes to absorb HOM energy and mitigate these effects. This thesis presents the design and optimization of several coaxial HOM couplers for the 5-cell 801.58 MHz elliptical Nb cavities of the 500 MeV PERLE ERL configuration. The RF transmission of the HOM couplers was optimized to enhance the damping of the most dangerous HOMs. The optimized HOM couplers were integrated into endgroups to simulate their damping performance and thermal behavior. The optimized HOM couplers were 3D-printed in epoxy and copper-coated. Low-power RF measurements were conducted on the produced HOM couplers installed in copper PERLE-type cavities to validate their damping performance and propose several endgroups for the PERLE 5-cell cavity to mitigate HOMs below the BBU instability limits.
Barbagallo, Carmelo↗
ECFA Higgs, electroweak, and top Factory Study
The ECFA Higgs, electroweak, and top Factory Study ran between 2021 and 2025 as a broad effort across the experimental and theoretical particle physics communities, bringing together participants from many different proposed future collider projects. Activities across three main working groups advanced the joint development of tools and analysis techniques, fostered new considerations of detector design and optimisation, and led to a new set of studies resulting in improved projected sensitivities across a wide physics programme. This report demonstrates the significant expansion in the state-of-the-art understanding of the physics potential of future e+e- Higgs, electroweak, and top factories, and has been submitted as input to the 2025 European Strategy for Particle Physics Update.
Altmann, J. [Monash U.]↗
Rapid Inference of Logic Gate Neural Networks for Anomaly Detection in High Energy Physics
The increasing data rates and complexity of detectors at the Large Hadron Collider (LHC) necessitate fast and efficient machine learning models, particularly for rapid selection of what data to store, known as triggering. Building on recent work in differentiable logic gates, we present a public implementation of a Convolutional Differentiable Logic Gate Neural Network (CLGN). We apply this to detecting anomalies at the Level-1 Trigger at CMS using public data from the CICADA project. We demonstrate that the CLGN achieves physics performance on par with or superior to conventional quantized neural networks. We also synthesize an LGN for a Field-Programmable Gate Array (FPGA) and show highly promising FPGA characteristics, notably zero Digital Signal Processor (DSP) resource usage. This work highlights the potential of logic gate networks for high-speed, on-detector inference in High Energy Physics and beyond.
FOS: Physical sciences↗
Trigger Detection for the sPHENIX Experiment via Bipartite Graph Networks with Set Transformer
Trigger (interesting events) detection is crucial to high-energy and nuclear physics experiments because it improves data acquisition efficiency. It also plays a vital role in facilitating the downstream offline data analysis process. The sPHENIX detector, located at the Relativistic Heavy Ion Collider in Brookhaven National Laboratory, is one of the largest nuclear physics experiments on a world scale and is optimized to detect physics processes involving charm and beauty quarks. Furthermore, these particles are produced in collisions involving two proton beams, two gold nuclei beams, or a combination of the two and give critical insights into the formation of the early universe. This paper presents a model architecture for trigger detection with geometric information from two fast silicon detectors. Transverse momentum is introduced as an intermediate feature from physics heuristics. We also prove its importance through our training experiments. Each event consists of tracks and can be viewed as a graph. A bipartite graph neural network is integrated with the attention mechanism to design a binary classification model. Compared with the state-of-the-art algorithm for trigger detection, our model is parsimonious and increases the accuracy and the AUC score by more than 15%.
97 MATHEMATICS AND COMPUTING↗
Benchmark eA generator for leptoproduction in high-energy lepton-nucleus collisions
The upcoming electron-ion collider (EIC) will address several outstanding puzzles in modern nuclear physics. Topics such as the partonic structure of nucleons and nuclei, the origin of their mass and spin, among others, can be understood via the study of high-energy electron-proton (ep) and electron-nucleus (eA) collisions. Achieving the scientific goals of the EIC will require a novel electron-hadron collider and detectors capable to perform high-precision measurements but also dedicated tools to model and interpret the data. To aid in the latter, we present a general-purpose e A Monte Carlo generator—BeAGLE. In this paper, we provide a general description of the models integrated into BeAGLE, applications of BeAGLE in eA physics, implications for detector requirements at the EIC, and the tuning of the parameters in BeAGLE based on available experimental data. Specifically, we focus on a selection of model and data comparisons in particle production in both ep and eA collisions, where baseline particle distributions provide essential information to characterize the event. In addition, we investigate the collision geometry determination in eA collisions, which could be used as an experimental tool for varying the nuclear density.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Future high energy colliders and options for the U.S.
The United States has a rich history in high energy particle accelerators and colliders — both lepton and hadron machines, which have enabled several major discoveries in elementary particle physics. To ensure continued progress in the field, U.S. leadership as a key partner in building next generation collider facilities abroad is essential; also critically important is to prepare to host an energy frontier collider in the U.S. once the construction of the LBNF/DUNE project is completed. In this paper, we briefly discuss the ongoing and potential U.S. engagement in proposed collider projects abroad and present a number of future collider options we have studied for hosting an energy frontier collider in the U.S. Further, we also call for initiating an integrated national R&D program in the U.S. now, focused on future colliders.
43 PARTICLE ACCELERATORS↗