Hasil untuk "Nuclear and particle physics. Atomic energy. Radioactivity"

M. L. Bissell, M. Jankowski, A. Antušek et al.

To date, the magnetic structure of nuclei has been poorly constrained, with limited information on its spatial distribution. In this work, we address the composition and distribution of nuclear magnetization in a precision study of short-lived $^{47}$K. We measure the Larmor frequency with part-per-million precision using liquid-state $β$-detected nuclear magnetic resonance at CERN-ISOLDE, improving determination of the experimental differential hyperfine anomaly relative to $^{39}$K by more than an order of magnitude. By combining these experimental results with relativistic all-orders atomic calculations and nuclear density functional theory, we obtain the relative spin and orbital contributions to the nuclear magnetic moments. Our analysis reveals an overestimation of the spin contribution predicted by nuclear theory, that persists even after considering two-body currents. Conversely, we show that the measured hyperfine anomaly is reproduced when adopting the spatial distribution of nuclear magnetization provided by density functional theory. The methodology introduced in this work establishes a means to probe the detailed magnetic structure of the nucleus. This is critical for benchmarking nuclear structure theory and calculations of symmetry-violating nuclear moments relevant to searches for physics beyond the Standard Model in atoms and molecules.

A.A. Araújo Filho, N. Heidari, A. Övgün

This work explores both classical and quantum aspects of an axisymmetric black hole within a non–commutative gauge theory. The rotating solution is derived using a modified Newman–Janis procedure. The analysis begins with the horizon structure, ergospheres, and angular velocity. The thermodynamic properties are examined through surface gravity, focusing on the Hawking temperature, entropy, and heat capacity. In addition, the remnant mass is calculated. The Hawking radiation is treated as a tunneling process for bosonic and fermionic particles, along with the corresponding particle creation density. Geodesic motion is explored, emphasizing null geodesics, radial accelerations, the photon sphere, and black hole shadows. Finally, the gravitational lensing in the strong deflection limit is investigated.

Jeongwon Lee, Jayhyun Kim, Jinsu Kim et al.

This study presents a machine learning model for predicting plasma disruptions using the KSTAR database. The model employs a long short-term memory (LSTM) network to capture temporal patterns in zero-dimensional plasma signals. A total of 668 disruption shots and 113 non-disruption shots from the 2019 to 2022 carbon divertor campaigns were used, divided into training, validation, and test sets. The architecture combines a multi-input LSTM and a fully connected neural network, using 30 features sampled over a 1 s window. The model achieved an AUC of 0.88 for individual samples and an F1 score of 0.91 in shot-by-shot evaluation, with over 90% accuracy for both disruption and non-disruption shots. Additional analysis using permutation importance and t-SNE visualization identified key features and confirmed the model’s interpretability. With an inference time of ∼3.1 ms per sample, the model shows strong potential for real-time application in plasma control systems.

Zhongtian Liu, Wei Li, Xiang Zhang et al.

The High Energy Photon Source (HEPS) Linac is a normal-conducting electron linear accelerator capable of producing high bunch charge beam. Its bunching system includes two subharmonic bunchers (SHBs), one prebuncher, one buncher, and one accelerating structure. The SHB is commonly used in the low-energy section for longitudinal bunching to increase the bunch charge. The phase and voltage of the SHB are crucial for obtaining a high-quality electron beam in Linac. This paper presents a method for calibrating the phase and voltage of the SHB using the time-of-flight technique. Experiments were conducted at the HEPS Linac using two beam position monitors. According to the simulations, we found that bunch length and space charge effect have a significant impact on the results, and we propose corrective measures to address them. To enhance experimental efficiency, we propose a data processing method called the truncated averaging technique that eliminates the need for corrective measures, which has been validated through both simulations and experiments, yielding outstanding results. This paper presents detailed insights into both the simulation and experimental procedures.

D. Maurin, L. Audouin, E. Berti et al.

Cosmic-ray physics in the GeV-to-TeV energy range has entered a precision era thanks to recent data from space-based experiments. However, the poor knowledge of nuclear reactions, in particular for the production of antimatter and secondary nuclei, limits the information that can be extracted from these data, such as source properties, transport in the Galaxy and indirect searches for particle dark matter. The Cross-Section for Cosmic Rays at CERN workshop series has addressed the challenges encountered in the interpretation of high-precision cosmic-ray data, with the goal of strengthening emergent synergies and taking advantage of the complementarity and know-how in different communities, from theoretical and experimental astroparticle physics to high-energy and nuclear physics. In this paper, we present the outcomes of the third edition of the workshop that took place in 2024. We present the current state of cosmic-ray experiments and their perspectives, and provide a detailed road map to close the most urgent gaps in cross-section data, in order to efficiently progress on many open physics cases, which are motivated in the paper. Finally, with the aim of being as exhaustive as possible, this report touches several other fields -- such as cosmogenic studies, space radiation protection and hadrontherapy -- where overlapping and specific new cross-section measurements, as well as nuclear code improvement and benchmarking efforts, are also needed. We also briefly highlight further synergies between astroparticle and high-energy physics on the question of cross-sections.

A. Arectout, H. Boukhal, E. Chakir et al.

This work aims to study the response function of a 2″×2″ NaI(Tl) scintillation detector using Monte Carlo simulations. A precise mathematical model of the NaI(Tl) scintillator was developed using both FLUKA and GAMOS Monte Carlo simulation software. The photon pulse height distributions of the NaI(Tl) without influence of its energy resolution, obtained with FLUKA and GAMOS codes, were converted into a real NaI(Tl) response function using the necessary conversion process. Spectral characteristics such as full-energy peak efficiency, energy resolution, peak-to-Compton ratio, and peak-to-total ratio were investigated by simulation at different gamma-ray energy obtained from 109Cd, 137Cs, 54Mn, 65Zn, and 60Co sources. The simulated spectra from the GAMOS code were consistent with those generated by the FLUKA code. Additionally, the comparison between simulated results and experimental data demonstrated good agreement. The validation of the computational models used for the NaI(Tl) detector in both FLUKA and GAMOS software was successfully achieved, confirming the accuracy of the simulations in replicating the detector's response.

D. S. Cabral, A. F. Santos, R. Bufalo

Abstract In this paper we examine the pair production through the Breit–Wheeler process $$\gamma ~\gamma \rightarrow e^+ e^-$$ γ γ → e + e - in a thermal background. We compute the thermal contribution to the Breit–Wheeler differential cross section within the thermofield dynamics formalism. We evaluate in details the cross section for this process, which possess a surprisingly simple expression valid for any temperature $$\beta $$ β , from which we discuss some physically relevant aspects. We also consider the high temperature regime of the cross section in order to have a better understanding about its thermal behavior.

Ante Ravlić, Esra Yüksel, Tamara Nikšić et al.

A clear connection can be established between properties of nuclear matter and finite-nuclei observables, such as the correlation between the slope of the symmetry energy and dipole polarizability, or between compressibility and the isoscalar monopole giant resonance excitation energy. Establishing a connection between realistic atomic nuclei and an idealized infinite nuclear matter leads to a better understanding of underlying physical mechanisms that govern nuclear dynamics. In this work, we aim to study the dependence of the binding energies and related quantities (e.g. location of drip lines, the total number of bound even-even nuclei) on the symmetry energy $S_2(ρ)$. The properties of finite nuclei are calculated by employing the relativistic Hartree-Bogoliubov (RHB) model, assuming even-even axial and reflection symmetric nuclei. Calculations are performed by employing two families of relativistic energy density functionals (EDFs), based on different effective Lagrangians, constrained to a specific symmetry energy at saturation density $J$ within the interval of $30$--$36$ MeV. Nuclear binding energies and related quantities of bound nuclei are calculated between $8 \leq Z \leq 104$ from the two-proton to the two-neutron drip line. As the neutron drip line is approached, the interactions with stiffer $J$ tend to predict more bound nuclei, resulting in a systematic shift of the two-neutron drip line towards more neutron-rich nuclei. Consequentially, a correlation between the number of bound nuclei $N_{nucl}$ and $S_2(ρ)$ is established for a set of functionals constrained using the similar optimization procedures. The direction of the relationship between the number of bound nuclei and symmetry energy highly depends on the density under consideration.

A. Tumasyan, W. Adam, J. W. Andrejkovic et al.

Abstract Using a data sample of $$\sqrt{s}=13\,\text {TeV}$$ s = 13 TeV proton-proton collisions collected by the CMS experiment at the LHC in 2017 and 2018 with an integrated luminosity of $$103\text {~fb}^{-1}$$ 103 fb - 1 , the $$\text {B}^{0}_{\mathrm{s}} \rightarrow \uppsi (\text {2S})\text {K}_\mathrm{S}^{0}$$ B s 0 → ψ ( 2S ) K S 0 and $$\text {B}^{0} \rightarrow \uppsi (\text {2S})\text {K}_\mathrm{S}^{0} \uppi ^+\uppi ^-$$ B 0 → ψ ( 2S ) K S 0 π + π - decays are observed with significances exceeding 5 standard deviations. The resulting branching fraction ratios, measured for the first time, correspond to $${\mathcal {B}}(\text {B}^{0}_{\mathrm{s}} \rightarrow \uppsi (\text {2S})K_\mathrm{S}^{0})/{\mathcal {B}}(\text {B}^{0}\rightarrow \uppsi (\text {2S})K_\mathrm{S}^{0}) = (3.33 \pm 0.69 (\text {stat})\, \pm 0.11\,(\text {syst}) \pm 0.34\,(f_{\mathrm{s}}/f_{\mathrm{d}})) \times 10^{-2}$$ B ( B s 0 → ψ ( 2S ) K S 0 ) / B ( B 0 → ψ ( 2S ) K S 0 ) = ( 3.33 ± 0.69 ( stat ) ± 0.11 ( syst ) ± 0.34 ( f s / f d ) ) × 10 - 2 and $${\mathcal {B}}(\text {B}^{0} \rightarrow \uppsi (\text {2S})\text {K}_\mathrm{S}^{0} \uppi ^{+} \uppi ^{-})/ {\mathcal {B}}(\text {B}^{0} \rightarrow \uppsi (\text {2S})\text {K}^{0}_{\mathrm{S}}) = 0.480 \pm 0.013\,(\text {stat}) \pm 0.032\,(\text {syst})$$ B ( B 0 → ψ ( 2S ) K S 0 π + π - ) / B ( B 0 → ψ ( 2S ) K S 0 ) = 0.480 ± 0.013 ( stat ) ± 0.032 ( syst ) , where the last uncertainty in the first ratio is related to the uncertainty in the ratio of production cross sections of $$\hbox {B}^{0}_{\mathrm{s}}$$ B s 0 and $$\hbox {B}^{0}$$ B 0 mesons, $$f_{\mathrm{s}}/f_{\mathrm{d}}$$ f s / f d .

Fayez Abu-Ajamieh

Abstract Measuring the Higgs couplings accurately at colliders is one of the best routes for finding physics Beyond the Standard Model (BSM). If the measured couplings deviate from the SM predictions, then this would give rise to energy-growing processes that violate tree-level unitarity at some energy scale, indicating new physics. In this paper, we extend previous work on unitarity bounds from the Higgs potential and the Higgs couplings to vector bosons and the top quark; to the Higgs couplings to γγ and γZ. We find that while the HL-LHC might be able to find new physics in the γZ sector, the scale of new physics in both sectors is mostly beyond its reach. However, accurate measurements of the leading couplings of the two sectors in the HL-LHC can place stringent limits on both the scale of new physics and on other Higgs couplings that are difficult to measure. In addition, the scale of new physics is mostly within the reach of the 100 TeV collider.

A. Ekström, C. Forssén, G. Hagen et al.

Ab initio has been used as a label in nuclear theory for over two decades. Its meaning has evolved and broadened over the years. We present our interpretation, briefly review its historical use, and discuss its present-day relation to theoretical uncertainty quantification.

Christoph Chiaffrino, Olaf Hohm, Allison F. Pinto

Abstract We show that the perturbative expansion of general gauge theories can be expressed in terms of gauge invariant variables to all orders in perturbations. In this we generalize techniques developed in gauge invariant cosmological perturbation theory, using Bardeen variables, by interpreting the passing over to gauge invariant fields as a homotopy transfer of the strongly homotopy Lie algebras encoding the gauge theory. This is illustrated for Yang-Mills theory, gravity on flat and cosmological backgrounds and for the massless sector of closed string theory. The perturbation lemma yields an algorithmic procedure to determine the higher corrections of the gauge invariant variables and the action in terms of these.

Ansgar Denner, Giovanni Pelliccioli

Abstract The high luminosity that will be accumulated at the LHC will enable precise differential measurements of the hadronic production of a top–antitop-quark pair in association with a $$\text {W} $$ W  boson. Therefore, an accurate description of this process is needed for realistic final states. In this work we combine for the first time the NLO QCD and electroweak corrections to the full off-shell $$\text {t} \overline{\text {t}}\text {W} ^+$$ t t ¯ W + production at the LHC in the three-charged-lepton channel, including all spin correlations, non-resonant effects, and interferences. To this end, we have computed the NLO electroweak radiative corrections to the leading QCD order as well as the NLO QCD corrections to both the QCD and the electroweak leading orders.

Ihor M. Kadenko, Nadiia V. Sakhno, Oleksandr M. Gorbachenko et al.

This paper deals with the formation of a bound dineutron in the outgoing channel of the $^{159}$Tb(n,$^2$n)$^{158g}$Tb nuclear reaction followed by assumed transformations of this reaction products $^{159g}$Tb and $^2$n. Such nuclear processes were studied in detail from the point of view of $^{160}$Tb / $^{160}$Dy / $^{160}$Ho amount of nuclei versus time dependence. Some signs of fusion process between heavier nuclei ($^{158}$Tb and/or $^{158}$Gd) and the deuteron, that is a bound dineutron decay product, were detected as unexpected increasing of 879.38 keV gamma-ray peak count rate due to $^{160}$Dy gamma-transitions. The mathematical model, including three systems of differential equations, was developed to describe the experimental data. This development requires a reasonable estimate of the half-life of a bound dineutron, which was found to be equal 5,877 s as an upper limit. We mathematically modeled the experimentally observed delayed in time buildup of the $^{160}$Tb radioactivity with a maximum at about 495 d since the neutron irradiation completion of the Tb sample, based on the similarity with the parent-daughter nuclei radioactivity decay and nuclear accumulation processes.

Yukinari Sumino, Hiromasa Takaura

Abstract We investigate the u = 1 / 2 O Λ QCD $$ u=1/2\left[\mathcal{O}\left({\Lambda}_{\mathrm{QCD}}\right)\right] $$ and u = 3 / 2 O Λ QCD 3 $$ u=3/2\left[\mathcal{O}\left({\Lambda}_{\mathrm{QCD}}^3\right)\right] $$ renormalons in the static QCD potential in position space and momentum space using the OPE of the potential-NRQCD effective field theory. This is an old problem and we provide a formal formulation to analyze it. In particular we present detailed examinations of the u = 3/2 renormalons. We clarify how the u = 3/2 renormalon is suppressed in the momentum-space potential in relation with the Wilson coefficient V A (r). We also point out that it is not straightforward to subtract the IR renormalon and IR divergences simultaneously in the multipole expansion. Numerical analyses are given, which clarify the current status of our knowledge on the perturbative series. The analysis gives a positive reasoning to the method for subtracting renormalons used in recent α s (M Z ) determination from the QCD potential.

A. H. Ajjath, Pulak Banerjee, Amlan Chakraborty et al.

Abstract We present the first results on the two-loop massless QCD corrections to the four-point amplitude b + b ¯ → H + H $$ b+\overline{b}\to H+H $$ in the five flavor scheme, treating bottom quarks as massless. This amplitude is sensitive to the trilinear Higgs boson coupling. Our two-loop result for this amplitude constitutes of purely virtual contributions to the next-to-next-to-leading order QCD predictions for the production of a pair of Higgs bosons at the Large Hadron Collider. Using these two loop amplitudes and exploiting the universality of the soft contributions in perturbative QCD, we obtain the NNLO QCD effects in the soft plus virtual approximation. We find that the inclusion of higher order terms reduce the uncertainties resulting from the unphysical renormalisation and factorisation scales.

Jin-Biao Wei, Jia-Jing Lu, G. F. Burgio et al.

We investigate properties of nuclear matter and examine possible correlations with neutron star observables for a set of microscopic nuclear equations of state derived within the Brueckner-Hartree-Fock formalism employing compatible three-body forces. We find good candidates for a realistic nuclear EOS up to high density and confirm strong correlations between neutron star radius, tidal deformability, and the pressure of betastable matter. No correlations are found with the saturation properties of nuclear matter.

Hirokazu Kawamura, Ken-ichi Harada, Tomoya Sato et al.

We have developed a unique neutralizer device that uses an yttrium target surrounded by a platinum wall to magneto-optically trap radioactive atoms. In general, the radioactive nucleus produced in a nuclear reaction is extracted and transported in ion form. For the magneto-optical trap, thermal neutralization must occur on the surface of a metal with a small work function. The converter can produce a neutral atomic beam with small angular divergence that, given the recycling of atoms and ions, converts ions into neutral atoms with remarkable efficiency. We demonstrated the ion neutralization process using stable rubidium and confirmed $10^6$ neutralized atoms in the magneto-optical trap. Additionally, the experiment using francium demonstrated the obtaining of neutralized francium atoms.

Zachary Hall, Jesse Thaler

Abstract We introduce soft drop isolation, a new photon isolation criterion inspired by jet substructure techniques. Soft drop isolation is collinear safe and is equivalent to Frixione isolation at leading non-trivial order in the small R limit. However, soft drop isolation has the interesting feature of being democratic, meaning that photons can be treated equivalently to hadrons for initial jet clustering. Taking advantage of this democratic property, we define an isolated photon subjet: a photon that is not isolated from its parent jet but is isolated within its parent subjet after soft drop declustering. The kinematics of this isolated photon subjet can be used to expose the QED splitting function, in which a quark radiates a photon, and we verify this behavior using both a parton shower generator and a perturbative calculation in the collinear limit.

N.A. Ispulov, A.Zh. Zhumabekov, A.B. Abdrakhmanov et al.

Статья посвящена использованию микроконтроллеров Arduino в среде LabVIEW. Описаны: технология подготовки и отладки среды ArduinoIDE и метод подключения Arduino к LabVIEW; ошибки и их исправление при подключении. Показана программа работы с описанием лицевой панели и принципиальной схемы устройства. Написана программа нахождения коэффициентов для термисторов. Реализовать эту широтно-импульсную модуляцию можно как программным, так и аппаратным способом. Первый из них нам не подходит, так как он захватывает все ресурсы микроконтроллера, а нам еще нужно организовать опрос датчика. Поэтому мы выбрали аппаратный способ, использующий внутренние ресурсы компьютера. Для его реализации используется оператор WriteAnalog(), который может выполняться в фоновом режиме. В современном мире все более широкое применение приобретает внедрение новой техники, как в промышленном хозяйстве, так и в бытовых нуждах. Для улучшения какой-либо техники разрабатываются методы эффективного использования энергии.