CyberSec Research

Resistive AC-coupled Silicon Detectors (RSDs) are silicon sensors which provide high temporal and spatial resolution. The RSD is a candidate sensor to be used in future tracking detectors with the objective of obtaining '4D' tracking, where timing information can be used along with spatial hits during track finding. 4D tracking will be an essential part of any future lepton or hadron collider and may even be feasible at the HL-LHC. For applications at hadron colliders, RSD sensors must be able to operate in high fluence environments in order to provide 4D tracking. However, the effects of radiation on RSDs have not been extensively studied. In this study, RSDs were irradiated to $1.0$, $2.0$, and $3.5 \times 10^{15}$~cm$^{-2}$ (1~MeV neutron equivalents) with both protons and neutrons. The sensors were then characterized electrically to study the acceptor removal and, for the first time in this doping concentration range, the donor removal. Then, the Transient Current Technique was used to begin investigating the signal charge sharing after irradiation. The results suggest an interesting trend between acceptor and donor removal, which is worthy of further study and could assist in improving radiation hardness of Low Gain Avalanche Diodes (LGADs).

Fermionic dark matter absorption on nuclear targets via neutral current interactions is explored using a non-relativistic effective field theory framework. An analysis of data from the PICO-60 C$_{3}$F$_{8}$ bubble chamber sets leading constraints on spin-independent absorption for dark matter masses below 23 MeV/$\textit{c}^2$ and establishes the first limits on spin-dependent absorptive interactions. These results demonstrate the sensitivity of bubble chambers to low-mass dark matter and underscore the importance of absorption searches in expanding the parameter space of direct detection experiments.

Precision measurements of Higgs boson differential production cross sections are a key tool to probe the properties of the Higgs boson and test the standard model. New physics can affect both Higgs boson production and decay, leading to deviations from the distributions that are expected in the standard model. In this paper, combined measurements of differential spectra in a fiducial region matching the experimental selections are performed, based on analyses of four Higgs boson decay channels ($\gamma\gamma$, ZZ$^{(*)}$, WW$^{(*)}$, and $\tau\tau$) using proton-proton collision data recorded with the CMS detector at $\sqrt{s}$ = 13 TeV, corresponding to an integrated luminosity of 138 fb$^{-1}$. The differential measurements are extrapolated to the full phase space and combined to provide the differential spectra. A measurement of the total Higgs boson production cross section is also performed using the $\gamma\gamma$ and ZZ decay channels, with a result of 53.4$^{+2.9}_{-2.9}$ (stat)$^{+1.9}_{-1.8}$ (syst) pb, consistent with the standard model prediction of 55.6 $\pm$ 2.5 pb. The fiducial measurements are used to compute limits on Higgs boson couplings using the $\kappa$-framework and the SM effective field theory.

SuperSUN, a new superthermal source of ultracold neutrons (UCN) at the Institut Laue-Langevin, exploits inelastic scattering of neutrons in isotopically pure superfluid $^4$He at temperatures below $0.6\,$K. For the first time, continuous operation with an intense broad-spectrum cold neutron beam is demonstrated over 60 days. We observe continuous UCN extraction rates of $21000\,$s$^{-1}$, and storage in the source with saturated $\textit{in-situ}$ density $273\,$cm$^{-3}$. The high stored density, low-energy UCN spectrum, and long storage times open new possibilities in fundamental and applied physics.

This paper presents the reconstruction and performance evaluation of the FASER$\nu$ emulsion detector, which aims to measure interactions from neutrinos produced in the forward direction of proton-proton collisions at the CERN Large Hadron Collider. The detector, composed of tungsten plates interleaved with emulsion films, records charged particles with sub-micron precision. A key challenge arises from the extremely high track density environment, reaching $\mathcal{O}(10^5)$ tracks per cm$^2$. To address this, dedicated alignment techniques and track reconstruction algorithms have been developed, building on techniques from previous experiments and introducing further optimizations. The performance of the detector is studied by evaluating the single-film efficiency, position and angular resolution, and the impact parameter distribution of reconstructed vertices. The results demonstrate that an alignment precision of 0.3 micrometers and robust track and vertex reconstruction are achieved, enabling accurate neutrino measurements in the TeV energy range.

The study of novel quantum materials relies on muon-spin rotation, relaxation, or resonance (\mSR) measurements. Yet, a fundamental limitation persists: many of these materials can only be synthesized in extremely small quantities, often at sub-millimeter scales. While \mSR ~offers unique insights into electronic and magnetic properties, existing spectrometers lack a sub-millimeter spatial resolution and the possibility of triggerless pump-probe data acquisition, which would enable more advanced measurements. The General Purpose Surface-muon instrument (GPS) at the Paul Scherrer Institute (PSI) is currently limited to a muon stopping rate of \SI{40}{\kilo\hertz} to \SI{120}{\kilo\hertz}, a constraint that will become more pressing with the upcoming High-Intensity Muon Beam (HIMB) project. To overcome these challenges, we demonstrate the feasibility of employing ultra-thin monolithic Si-pixel detectors to reconstruct the stopping position of muons within the sample, thereby significantly enhancing the capability of measuring at higher muon rate. Additionally, we explore the first steps toward a triggerless pump-probe \mSR ~measurement scheme. Unlike conventional pump-probe techniques that require external triggers, a triggerless readout system can continuously integrate stimuli pulses into the data stream, allowing real-time tracking of ultra-fast dynamics in quantum materials. This approach will enable the study of transient states, spin dynamics, and quantum coherence under external stimuli.

In this contribution, we evaluate the sensitivity for particles with charges much smaller than the electron charge with a dedicated scintillator-based detector in the far forward region at the CERN LHC, FORMOSA. This contribution will outline the scientific case for this detector, its design and potential locations, and the sensitivity that can be achieved. The ongoing efforts to prove the feasibility of the detector with the FORMOSA demonstrator will be discussed. Finally, possible upgrades to the detector through the use of high-performance scintillator will be discussed.

The Proton EDM Experiment (pEDM) is the first direct search for the proton electric dipole moment (EDM) with the aim of being the first experiment to probe the Standard Model (SM) prediction of any particle EDM. Phase-I of pEDM will achieve $10^{-29} e\cdot$cm, improving current indirect limits by four orders of magnitude. This will establish a new standard of precision in nucleon EDM searches and offer a unique sensitivity to better understand the Strong CP problem. The experiment is ideally positioned to explore physics beyond the Standard Model (BSM), with sensitivity to axionic dark matter via the signal of an oscillating proton EDM and across a wide mass range of BSM models from $\mathcal{O}(1\text{GeV})$ to $\mathcal{O}(10^3\text{TeV})$. Utilizing the frozen-spin technique in a highly symmetric storage ring that leverages existing infrastructure at Brookhaven National Laboratory (BNL), pEDM builds upon the technological foundation and experimental expertise of the highly successful Muon $g$$-$$2$ Experiments. With significant R\&D and prototyping already underway, pEDM is preparing a conceptual design report (CDR) to offer a cost-effective, high-impact path to discovering new sources of CP violation and advancing our understanding of fundamental physics. It will play a vital role in complementing the physics goals of the next-generation collider while simultaneously contributing to sustaining particle physics research and training early career researchers during gaps between major collider operations.

As in previous decades, a comprehensive understanding of the intricate internal configuration of hadrons continues to be a central objective within both experimental and theoretical hadron physics. This pursuit plays a pivotal role in advancing our knowledge of QCD and critically evaluating the robustness and accuracy of the theoretical models developed to date. Furthermore, deciphering the underlying mechanisms of exotic states, both those currently observed and those anticipated in future experiments, remains a pressing and unresolved challenge. Motivated by this, in the present study, we investigate the electromagnetic properties of the $D \bar D_1(2420)$ and $D^* \bar D^*(2400)$ molecular tetraquark states with quantum numbers $J^{PC} = 1^{--}$, using the QCD light-cone sum rule method. These states are analyzed within a hadronic molecular framework, where their magnetic and quadrupole moments are computed to probe internal structure and geometric deformation. Our results reveal distinct electromagnetic signatures, with the magnetic moments primarily dominated by light-quark contributions, and the quadrupole moments suggesting an oblate charge distribution. The findings are compared with prior studies assuming compact tetraquark configurations, emphasizing the sensitivity of electromagnetic observables to the underlying hadronic structure. This analysis provides critical insights into the nature of exotic hadrons and contributes to the broader understanding of QCD dynamics in the non-perturbative regime.

Kaon physics can be used to independently determine three out of the four parameters of the CKM matrix, without any B physics input. Treating one parameter, $|V_{us}|$, or alternatively Wolfenstein $\lambda$, as well known, we show that the natural plane for the presentation of kaon CKM information is spanned by the combinations $\left(A^2(1-\hat\rho),\, A^2 \hat\eta\right)$. In this way, the use of B physics inputs is avoided, as well as the artificial inflation of errors due to parametric uncertainties, mainly due to $|V_{cb}|$. We show that the current status of kaon CKM constraints, impacted by recent advances in measurement and theory, is characterized by four allowed regions, and find that incoming data will inevitably disfavor a number of them, either confirming the CKM paradigm as dominant, or discovering a departure from the Standard Model.

A metric on the space of collider physics data enables analysis of its geometrical properties, like dimensionality or curvature, as well as quantifying the density with which a finite, discrete ensemble of data samples the space. We provide the first systematically-improvable precision calculations on this dataspace, presenting predictions resummed to next-to-leading logarithmic accuracy, using the Spectral Energy Mover's Distance (SEMD) as its metric. This is accomplished by demonstration of factorization of soft and collinear contributions to the metric at leading power and renormalization group evolution of the single-scale functions that are present in the factorization theorem. As applications of this general framework, we calculate the two-point correlator between pairs of jets on the dataspace, and the measure of the non-Gaussian fluctuations in a finite dataset. For the non-Gaussianities, our calculations validate the existence of a universal structure that had been previously observed in simulated data. As byproducts of this analysis, we also calculate the two-loop anomalous dimension of the SEMD metric and show that the original Energy Mover's Distance metric is identical to the SEMD through next-to-next-to-leading logarithmic accuracy.

Quantum contextuality refers to the impossibility of assigning a predefined, intrinsic value to a physical property of a system independently of the context in which the property is measured. It is, perhaps, the most fundamental feature of quantum mechanics. The many states with different spin that particle physics provides are the ideal setting for testing contextuality. We verify that the polarization states of single spin-1 massive particles produced at colliders are contextual. We test $W^{+}$ gauge bosons produced in top-quark decays, $J/\psi$ and $K^{*}(892)^0$ mesons in $B$-meson decays and $\phi$ mesons in $\chi^0_c$ and $\chi^1_c$ charmonium decays by reinterpreting the data and the analyses of the ATLAS, LHCb, Belle II and BESIII experimental collaborations, respectively. The polarization states of these four particles show contextuality with a significance larger than $5\sigma$. We also discuss the presence of quantum contextuality in spin states of bipartite systems formed by spin-1/2 particles. We test $\Lambda$ and $\Sigma$ baryons reinterpreting two BESIII data analyses, and pairs of top quarks utilizing a recent analysis of the CMS collaboration. Quantum contextuality is present with a significance exceeding $5\sigma$ also in these cases. In addition, we study the feasibility of testing quantum contextuality by means of $Z$ boson production in association with the Higgs boson, $Z$ and $W$ bosons pairs created in Higgs boson decays and with pairs of $\tau$ leptons. For the latter, we use Monte Carlo simulations that mimic the settings of SuperKEKB and of future lepton colliders. Experiments at high energies, though not designed for the purpose, perform surprisingly well in testing for quantum contextuality.

We describe a resonant cavity search apparatus for axion dark matter constructed by the Quantum Sensors for the Hidden Sector (QSHS) collaboration. The apparatus is configured to search for QCD axion dark matter, though also has the capability to detect axion-like particles (ALPs), dark photons, and some other forms of wave-like dark matter. Initially, a tuneable cylindrical oxygen-free copper cavity is read out using a low noise microwave amplifier feeding a heterodyne receiver. The cavity is housed in a dilution refrigerator and threaded by a solenoidal magnetic field, nominally 8T. The apparatus also houses a magnetic field shield for housing superconducting electronics, and several other fixed-frequency resonators for use in testing and commissioning various prototype quantum electronic devices sensitive at a range of axion masses in the range $\rm 2.0$ to $\rm 40\,eV/c^2$. We present performance data for the resonator, dilution refrigerator, and magnet, and plans for the first science run.

In this work, we investigate the discovery reach of a new physics model, the Inert Doublet Model, at an $e^+e^-$ machine with centre-of-mass energies $\sqrt{s}$ of 240 and 365 GeV. Within this model, four additional scalar bosons ($H$, $A$, $H^+$ and $H^-$) are predicted. Due to an additional symmetry, the lightest new scalar, here chosen to be $H$, is stable and provides an adequate dark matter candidate. The search for pair production of the new scalars is investigated in final states with two electrons or two muons, in the context of the future circular collider proposal, FCC-ee. Building on previous studies in the context of the CLIC proposal, this analysis extends the search to detector-level objects, using a parametric neural network to enhance the signal contributions over the Standard Model backgrounds, and sets limits in the $m_A-m_H$ vs $m_H$ plane. With a total integrated luminosity of 10.8 (2.7) ab$^{-1}$ for $\sqrt{s}=240$ (365) GeV, almost the entire phase-space available in the $m_A-m_H$ vs $m_H$ plane is expected to be excluded at 95% CL, reaching up to $m_H=110$ (165) GeV. The discovery reach is also explored, reaching $m_H= 108$ (157) GeV for $m_A-m_H=15$ GeV at $\sqrt{s}=240$ (365) GeV.

A search is performed for pairs of light pseudoscalar bosons (a) produced from decays of the 125 GeV Higgs boson ($\text{h}_{125}$). The analysis is based on publicly available data collected in 2016 by the CMS experiment at the LHC in proton-proton collisions at a center-of-mass energy of 13 TeV. The amount of data analyzed corresponds to an integrated luminosity of 16.4 $\text{fb}^{-1}$. The analysis explores for the first time at the LHC the final state exhibiting two muons and two c-quarks, which originate from flavor-asymmetric decays of the pseudoscalar pair. The search probes the pseudoscalar boson mass interval comprised between 4 and 11 GeV, which represents a region where the light bosons exhibit a considerable Lorentz boost, and thus their decay products overlap. No significant deviation from the standard model expectation is observed. Model-independent upper limits at 95% confidence level are set on the product of the cross section and branching fraction for the ${\text{h}_{125} \rightarrow \text{a}\text{a} \rightarrow \mu^{-}\mu^{+} c\bar{c}}$ process relative to the standard model Higgs boson production cross section, reaching a minimum value close to $3.3 \times 10^{-4}$. The results are interpreted in the context of two Higgs doublets plus singlet models and compared to existing experimental results covering other decay channels. The exclusion limits obtained by this search improve the current constraints set by various LHC searches in scenarios where the coupling of the light boson to up-type quarks is enhanced.

In view of difficulty to reproduce observables in the $D^0-\bar{D}^0$ mixing via the operator product expansion, we discuss the Dyson-Schwinger approach to this process. Formulated by the parameterization of quark propagators, SU(3) breaking relevant to charm mixing is evaluated in such a way that properly takes account of dynamical chiral symmetry breaking. The $\bar{D}^0\to D^0$ transition is discussed in the vacuum-insertion approximation with locality of the light valence-quark field, represented by the decay constant of $D^0$ meson as well as relevant momentum integrals. It is found that dimensionless mass-difference observable in this approach leads to $|x|=(1.3-2.9)\times 10^{-3}$, the order of magnitude comparable to the HFLAV data, and thereby offering a certain improvement as a theoretical framework.

Rare event experiments, such as those targeting dark matter interactions and neutrinoless double beta (0$\nu\beta\beta$) decay, should be shielded from gamma-rays that originated in rock. This paper describes the simulation of gamma-ray transport through the water shielding and assessment of the thickness needed to suppress the background from rock down to a negligible level. This study focuses on a next-generation xenon observatory with a wide range of measurements including the search for Weakly Interacting Massive Particles (WIMPs) and 0$\nu\beta\beta$ decay of $^{136}$Xe. Our findings indicate that the gamma-ray background is unlikely to persist through analysis cuts in the WIMP energy range (0 - 20 keV) after 3.5 m of water, complemented by 0.5 m of liquid scintillator. For 0$\nu\beta\beta$ decay, a background below 1 event in 10 years of running can be achieved with a fiducial mass of 39.3 tonnes. Furthermore, for typical radioactivity levels of 1 Bq kg$^{-1}$ of $^{232}$Th and $^{238}$U we have studied the effect of reducing the water shielding by 1 m, resulting in a reduced fiducial mass of 19.1 tonnes for 0$\nu\beta\beta$ decay and still a negligible background for WIMP search. The paper also presents the measurements of radioactivity in rock in the Boulby mine, which hosted several dark matter experiments in the past and is also a potential site for a future dual-phase xenon experiment. The measurements are used to normalise simulation results and assess the required shielding at Boulby.

Ultralight particles, with a mass below the electronvolt scale, exhibit wave-like behavior and have arisen as a compelling dark matter candidate. A particularly intriguing subclass is scalar dark matter, which induces variations in fundamental physical constants. However, detecting such particles becomes highly challenging in the mass range above $10^{-6}\,\text{eV}$, as traditional experiments face severe limitations in response time. In contrast, the matter effect becomes significant in a vast and unexplored parameter space. These effects include (i) a force arising from scattering between ordinary matter and the dark matter wind and (ii) a fifth force between ordinary matter induced by the dark matter background. Using the repulsive quadratic scalar-photon interaction as a case study, we develop a unified framework based on quantum mechanical scattering theory to systematically investigate these phenomena across both perturbative and non-perturbative regimes. Our approach not only reproduces prior results obtained through other methodologies but also covers novel regimes with nontrivial features, such as decoherence effects, screening effects, and their combinations. In particular, we highlight one finding related to both scattering and background-induced forces: the descreening effect observed in the non-perturbative region with large incident momentum, which alleviates the decoherence suppression. Furthermore, we discuss current and proposed experiments, including inverse-square-law tests, equivalence principle tests, and deep-space acceleration measurements. Notably, we go beyond the spherical approximation and revisit the MICROSCOPE constraints on the background-induced force in the large-momentum regime, where the decoherence and screening effects interplay. The ultraviolet models realizing the quadratic scalar-photon interaction are also discussed.