Nuclear Experiment

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New submissions for Friday, 21 June 2024 (showing 2 of 2 entries )

[1] arXiv:2406.13516 [pdf, html, other]

Title: Direct neutrino-mass measurement based on 259 days of KATRIN data

M. Aker, D. Batzler, A. Beglarian, J. Behrens, J. Beisenkötter, M. Biassoni, B. Bieringer, Y. Biondi, F. Block, S. Bobien, M. Böttcher, B. Bornschein, L. Bornschein, T. S. Caldwell, M. Carminati, A. Chatrabhuti, S. Chilingaryan, B. A. Daniel, K. Debowski, M. Descher, D. Díaz Barrero, P. J. Doe, O. Dragoun, G. Drexlin, F. Edzards, K. Eitel, E. Ellinger, R. Engel, S. Enomoto, A. Felden, C. Fengler, C. Fiorini, J. A. Formaggio, C. Forstner, F. M. Fränkle, K. Gauda, A. S. Gavin, W. Gil, F. Glück, S. Grohmann, R. Grössle, R. Gumbsheimer, N. Gutknecht, V. Hannen, L. Hasselmann, N. Haußmann, K. Helbing, H. Henke, S. Heyns, S. Hickford, R. Hiller, D. Hillesheimer, D. Hinz, T. Höhn, A. Huber, A. Jansen, C. Karl, J. Kellerer, K. Khosonthongkee, M. Kleifges, M. Klein, J. Kohpeiß, C. Köhler, L. Köllenberger, A. Kopmann, N. Kovač, A. Kovalík, H. Krause, L. La Cascio, T. Lasserre, J. Lauer, T. Le, O. Lebeda, B. Lehnert, G. Li, A. Lokhov M. Machatschek, M. Mark, A. Marsteller, E. L. Martin, C. Melzer, S. Mertens, S. Mohanty, J. Mostafa, K. Müller, A. Nava, H. Neumann, S. Niemes, A. Onillon, D. S. Parno, M. Pavan, U. Pinsook, A. W. P. Poon, J. M. Lopez Poyato, S. Pozzi, F. Priester, J. Ráliš, S. Ramachandran, R. G. H. Robertson, C. Rodenbeck, M. Röllig

Comments: 61 pages, 20 figures, 2 tables

Subjects: Nuclear Experiment (nucl-ex); High Energy Physics - Experiment (hep-ex)

The fact that neutrinos carry a non-vanishing rest mass is evidence of physics beyond the Standard Model of elementary particles. Their absolute mass bears important relevance from particle physics to cosmology. In this work, we report on the search for the effective electron antineutrino mass with the KATRIN experiment. KATRIN performs precision spectroscopy of the tritium $\beta$-decay close to the kinematic endpoint. Based on the first five neutrino-mass measurement campaigns, we derive a best-fit value of $m_\nu^{2} = {-0.14^{+0.13}_{-0.15}}~\mathrm{eV^2}$, resulting in an upper limit of $m_\nu < {0.45}~\mathrm{eV}$ at 90 % confidence level. With six times the statistics of previous data sets, amounting to 36 million electrons collected in 259 measurement days, a substantial reduction of the background level and improved systematic uncertainties, this result tightens KATRIN's previous bound by a factor of almost two.

[2] arXiv:2406.14387 [pdf, html, other]

Title: Dihadron Azimuthal Correlations in Deep-Inelastic Scattering Off Nuclear Targets

CLAS Collaboration

Comments: 32 pages, 17 figures

Subjects: Nuclear Experiment (nucl-ex)

We measured the nuclear dependence of the di-pion azimuthal correlation function in deep-inelastic scattering (DIS) using the CEBAF Large Acceptance Spectrometer (CLAS) and a 5 GeV electron beam. As the nuclear-target size increases, transitioning from deuterium to carbon, iron, and lead, the correlation function broadens monotonically. Its shape exhibits a significant dependence on kinematics, including the transverse momentum of the pions and the difference in their rapidity. None of the various Monte-Carlo event generators we evaluated could fully replicate the observed correlation functions and nuclear effects throughout the entire phase space. As the first study of its kind in DIS experiments, this research provides an important baseline for enhancing our understanding of the interplay between the nuclear medium and the hadronization process in hadron production.

Cross submissions for Friday, 21 June 2024 (showing 9 of 9 entries )

[3] arXiv:2406.12873 (cross-list from physics.ins-det) [pdf, other]

Title: Evidence for polyimide redeposition and possible correlation with sparks in Gas Electron Multipliers working in CF$_4$ mixtures

Thiago B. Saramela, Tiago F. Silva, Marco Bregant, Marcelo G. Munhoz, Tien T. Quach, Richard Hague, Ian S. Gilmore, Clive J. Roberts, Gustavo F. Trindade

Comments: 19 pages and 10 figures

Subjects: Instrumentation and Detectors (physics.ins-det); High Energy Physics - Experiment (hep-ex); Nuclear Experiment (nucl-ex)

Research on aging processes of Gas Electron Multipliers (GEMs) is important to obtain insights on how to increase detector's longevity, stability and performance, as highlighted in the latest developments roadmap by the European Council of Future Accelerators (ECFA). In this work, through the analysis of the molecular content on the surface of a used GEM, we provide evidences for polyimide redeposition as a source of organic material contributing to the formation of insulating layers on the electrodes, which eventually lead to sparks and detector failure. Furthermore, we show that chromium, used to promote adhesion between copper and polyimide, in the device undergoes a diffusion process, effectively blurring the layered structure. We demonstrate the significance of surface-sensitive chemical analysis to investigate the aging process of gaseous detectors and our results reveal the necessity of standardization and more stringent study protocols.

[4] arXiv:2406.12877 (cross-list from physics.ins-det) [pdf, html, other]

Title: Design of a SiPM-on-Tile ZDC for the future EIC and its Performance with Graph Neural Networks

Ryan Milton, Sebouh J. Paul, Barak Schmookler, Miguel Arratia, Piyush Karande, Aaron Angerami, Fernando Torales Acosta, Benjamin Nachman

Comments: 9 pages, 9 figures. Code and datasets included

Subjects: Instrumentation and Detectors (physics.ins-det); High Energy Physics - Experiment (hep-ex); Nuclear Experiment (nucl-ex)

We present a design for a high-granularity zero-degree calorimeter (ZDC) for the upcoming Electron-Ion Collider (EIC). The design uses SiPM-on-tile technology and features a novel staggered-layer arrangement that improves spatial resolution. To fully leverage the design's high granularity and non-trivial geometry, we employ graph neural networks (GNNs) for energy and angle regression as well as signal classification. The GNN-boosted performance metrics meet, and in some cases, significantly surpass the requirements set in the EIC Yellow Report, laying the groundwork for enhanced measurements that will facilitate a wide physics program. Our studies show that GNNs can significantly enhance the performance of high-granularity CALICE-style calorimeters by automating and optimizing the software compensation algorithms required for these systems. This improvement holds true even in the case of complicated geometries that pose challenges for image-based AI/ML methods.

[5] arXiv:2406.12878 (cross-list from physics.ins-det) [pdf, html, other]

Title: Beam test results of the prototype of the multi wire drift chamber for the CSR external-target experiment

Zhi Qin, Zhoubo He, Zhe Cao, Tao Chen, Zhi Deng, Limin Duan, Dong Guo, Rongjiang Hu, Jie Kong, Canwen Liu, Peng Ma, Xianglun Wei, Shihai Wen, Xiangjie Wen, Junwei Yan, Herun Yang, Zuoqiao Yang, Yuhong Yu, Zhigang Xiao

Subjects: Instrumentation and Detectors (physics.ins-det); High Energy Physics - Experiment (hep-ex); Nuclear Experiment (nucl-ex)

The half-size prototype of the multi wire drift chamber (MWDC) for the cooling storage ring (CSR) external-target experiment (CEE) was assembled and tested in 350 MeV/u Kr+Fe reactions on the heavy ion research facility in Lanzhou (HIRFL). The prototype consists of 6 sense layers, where the sense wires are stretched in three directions X, U and V, meeting $0^\circ$, $30^\circ$ and $-30^\circ$ with respect to the vertical axis, respectively. The sensitive area of the prototype is $76 {\rm cm} \times 76 {\rm cm}$. The amplified and shaped signals from the anode wires are digitized in a serial capacity array. Being operated with 1500 V high voltage on the anode wires, the efficiency for each layer is beyond 95\%. The tracking residual is about $301 \pm 2 \rm \mu m$. The performance meets the requirements of CEE.

[6] arXiv:2406.12882 (cross-list from physics.ins-det) [pdf, html, other]

Title: Examining LEGEND-1000 cosmogenic neutron backgrounds in Geant4 and MCNP

C.J. Barton, W. Xu, S.R. Elliott, R. Massarczyk

Comments: Pre-print for article submission to JINST

Journal-ref: JINST 19 P05056 (2024)

Subjects: Instrumentation and Detectors (physics.ins-det); Nuclear Experiment (nucl-ex)

For next-generation neutrinoless double beta decay experiments, extremely low backgrounds are necessary. An understanding of in-situ cosmogenic backgrounds is critical to the design effort. In-situ cosmogenic backgrounds impose a depth requirement and especially impact the choice of host laboratory. Often, simulations are used to understand background effects, and these simulations can have large uncertainties. One way to characterize the systematic uncertainties is to compare unalike simulation programs. In this paper, a suite of neutron simulations with identical geometries and starting parameters have been performed with Geant4 and MCNP, using geometries relevant to the LEGEND-1000 experiment. This study is an important step in gauging the uncertainties of simulations-based estimates. To reduce project risks associated with simulation uncertainties, a novel alternative shield of methane-doped liquid argon is considered in this paper for LEGEND-1000, which could achieve large background reduction without requiring significant modification to the baseline design.

[7] arXiv:2406.12885 (cross-list from physics.ins-det) [pdf, html, other]

Title: neuSIM4: A comprehensive GEANT4 based neutron simulation code

J. Park, F. C. E. Teh, M. B. Tsang, K. W. Brown, Z. Chajecki, B. Hong, T. Lokotko, W. G. Lynch, J. Wieske, K. Zhu

Subjects: Instrumentation and Detectors (physics.ins-det); Nuclear Experiment (nucl-ex)

A new neutron SIMulation program based on the versatile GEANT4 toolkit, neuSIM4, has been developed to describe interactions of neutrons in the NE213 liquid scintillator from 0.1 to 3000 MeV. neuSIM4 is designed to accommodate complicated modern detector geometry setups with multiple scintillator detectors, each of which can be outfitted with more than one photo-multiplier. To address a broad spectrum of neutron energies, two new neutron interaction physics models, KSCIN and NxQMD, have been implemented in GEANT4. For neutrons with energy below 110 MeV, we incorporate a total of eleven neutron induced reaction channels on hydrogen and carbon nuclei, including nine carbon inelastic reaction channels, into KSCIN. Beyond 110 MeV, we implement a neutron induced reaction model, NxQMD, in GEANT4. We use its results as reference to evaluate other neutron-interaction physics models in GEANT4. We find that results from an existing cascade physics model (INCL) in GEANT4 agree very well with the results from NxQMD, and results from both codes agree with new and existing light response data. To connect KSCIN to NxQMD or INCL, we introduce a transition region where the contribution of neuSIM4 linearly decreases with corresponding increased contributions from NxQMD or INCL. To demonstrate the application of the new code, we simulate the light response and performance of a 2 x 2 m2 neutron detector wall array consisting of 25 2m-long scintillation bars. We are able to compare the predicted light response functions to the shape of the experimental response functions and calculate the efficiency of the neutron detector array for neutron energies up to 200 MeV. These simulation results will be pivotal for understanding the performance of modern neutron arrays with intricate geometries, especially in the measurements of neutron energy spectra in heavy-ion reactions.

[8] arXiv:2406.13286 (cross-list from hep-ph) [pdf, html, other]

Title: Charm and Bottom Hadrons in Hot Hadronic Matter

Santosh K. Das, Juan M. Torres-Rincon, Ralf Rapp

Comments: 60 pages, 45 figures. Review article sent to Physics Reports journal

Subjects: High Energy Physics - Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)

Heavy quarks, and the hadrons containing them, are excellent probes of the QCD medium formed in high-energy heavy-ion collisions, as they provide direct information on the transport properties of the medium and how quarks color-neutralize into hadrons. Large theoretical and phenomenological efforts have been dedicated thus far to assess the diffusion of charm and bottom quarks in the quark-gluon plasma and their subsequent hadronization into heavy-flavor (HF) hadrons. However, the fireball formed in heavy-ion collisions also features an extended hadronic phase, and therefore any quantitative analysis of experimental observables needs to account for rescattering of charm and bottom hadrons. This is further reinforced by the presence of a QCD cross-over transition and the notion that the interaction strength is maximal in the vicinity of the pseudo-critical temperature. We review existing approaches for evaluating the interactions of open HF hadrons in a hadronic heat bath and the pertinent results for scattering amplitudes, spectral functions and transport coefficients. While most of the work to date has focused on $D$ mesons, we also discuss excited states as well as HF baryons and the bottom sector. Both the HF hadro-chemistry and bottom observables will play a key role in future experimental measurements. We also conduct a survey of transport calculations in heavy-ion collisions that have included effects of hadronic HF diffusion and assess their sensitivity to various observables.

[9] arXiv:2406.13703 (cross-list from hep-ph) [pdf, html, other]

Title: Working group 1 summary: $V_{ud}$, $V_{us}$, $V_{cd}$, $V_{cs}$ and semileptonic/leptonic $D$ decays

Bipasha Chakraborty, Alex Gilman, Martin Hoferichter, Michal Koval

Comments: 12 pages, 3 figures; presented at the 12th Workshop on the CKM Unitarity Triangle, 18-22 September 2023, Santiago de Compostela

Subjects: High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Experiment (hep-ex); High Energy Physics - Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)

We summarize the program of working group 1 at the 12th Workshop on the CKM Unitarity Triangle, whose main subjects covered $V_{ud}$, $V_{us}$, and first-row unitarity as well as $V_{cd}$, $V_{cs}$, and (semi-)leptonic $D$ decays.

[10] arXiv:2406.13863 (cross-list from nucl-th) [pdf, html, other]

Title: Revealing initial state properties through ultra-central symmetric heavy-ion collisions

S. M. A. Tabatabaee, S. F. Taghavi

Comments: 32 pages, 10 figures

Subjects: Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)

Heavy-ion experiments provide a new opportunity to gain a deeper understanding of the structure of nuclei. To achieve this, it is crucial to identify observables under circumstances that are minimally affected by the process that leads to the initial state of heavy-ion collisions from nuclear wavefunction. In this study, we demonstrate that when assuming scale-invariance, the effect of this stage on the initial energy or entropy density moments in ultra-central symmetric collisions is negligible for nucleon sizes of approximately 0.7 fm or larger for large nuclei. By borrowing cluster expansion method from statistical physics and using scale-invariance assumption, we calculate the average ellipticity of initial density at the presence of short-range correlation. We compare our calculations to Monte Carlo studies and assess the accuracy of various methods of short-range correlation sampling. Additionally, we find that the isobar ratio can constrain the initial state parameters, in addition to deformation. Our study indicates that the isobar ratios in ultra-central collisions are especially sensitive to the fluctuation in the weight of the nuclei constituents and the two-body correlation among nucleons. This insight is crucial for drawing conclusions about nuclear deformations based on isobar ratios.

[11] arXiv:2406.14467 (cross-list from astro-ph.HE) [pdf, html, other]

Title: A More Precise Measurement of the Radius of PSR J0740+6620 Using Updated NICER Data

Alexander J. Dittmann, M. Coleman Miller, Frederick K. Lamb, Isiah Holt, Cecilia Chirenti, Michael T. Wolff, Slavko Bogdanov, Sebastien Guillot, Wynn C. G. Ho, Sharon M. Morsink, Zaven Arzoumanian, Keith C. Gendreau

Comments: 18 pages, 8 figures, +appendices. Accepted in ApJ

Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)

PSR J0740+6620 is the neutron star with the highest precisely determined mass, inferred from radio observations to be $2.08\pm0.07\,\rm M_\odot$. Measurements of its radius therefore hold promise to constrain the properties of the cold, catalyzed, high-density matter in neutron star cores. Previously, Miller et al. (2021) and Riley et al. (2021) reported measurements of the radius of PSR J0740+6620 based on Neutron Star Interior Composition Explorer (NICER) observations accumulated through 17 April 2020, and an exploratory analysis utilizing NICER background estimates and a data set accumulated through 28 December 2021 was presented in Salmi et al. (2022). Here we report an updated radius measurement, derived by fitting models of X-ray emission from the neutron star surface to NICER data accumulated through 21 April 2022, totaling $\sim1.1$ Ms additional exposure compared to the data set analyzed in Miller et al. (2021) and Riley et al. (2021), and to data from X-ray Multi-Mirror (XMM-Newton) observations. We find that the equatorial circumferential radius of PSR J0740+6620 is $12.92_{-1.13}^{+2.09}$ km (68% credibility), a fractional uncertainty $\sim83\%$ the width of that reported in Miller et al. (2021), in line with statistical expectations given the additional data. If we were to require the radius to be less than 16 km, as was done in Salmi et al. (2024), then our 68% credible region would become $R=12.76^{+1.49}_{-1.02}$ km, which is close to the headline result of Salmi et al. (2024). Our updated measurements, along with other laboratory and astrophysical constraints, imply a slightly softer equation of state than that inferred from our previous measurements.

Replacement submissions for Friday, 21 June 2024 (showing 7 of 7 entries )

[12] arXiv:2105.13481 (replaced) [pdf, html, other]

Title: Hyperon Polarization from the Vortical Fluid in Low Energy Nuclear Collisions

Yu Guo, Jinfeng Liao, Enke Wang, Hongxi Xing, Hui Zhang

Comments: 5 pages, 4 figures, new results for hyperon local polarization are added

Journal-ref: Phys. Rev. C 104, 041902 (2021)

Subjects: Nuclear Theory (nucl-th); High Energy Physics - Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)

In 2017, STAR Collaboration reported the measurements of hyperon global polarization in heavy ion collisions, suggesting the subatomic fireball fluid created in these collisions as the most vortical fluid. There remains the interesting question: at which beam energy the truly most vortical fluid will be located. In this work we perform a systematic study on the beam energy dependence of hyperon global polarization phenomenon, especially in the interesting $\hat{O}(1\sim 10)\ \rm GeV$ region. We find a non-monotonic trend, with the global polarization to first increase and then decrease when beam energy is lowered from $27~\rm GeV$ down to $3~\rm GeV$. The maximum polarization signal has been identified around $\sqrt{s_{NN}} = 7.7~\rm GeV$, where the heavy ion collisions presumably create the most vortical fluid. Detailed experimental measurements in the $\hat{O}(1\sim 10)\ \rm GeV$ beam energy region are expected to test the prediction very soon.

[13] arXiv:2211.03968 (replaced) [pdf, html, other]

Title: Electromagnetic fields in ultra-peripheral relativistic heavy-ion collisions

Jie Zhao, Jinhui Chen, Xu-Guang Huang, Yu-Gang Ma

Comments: 5 pages, 4 figures, published version at NST

Journal-ref: Nuclear Science and Techniques, 35, 20 (2024)

Subjects: Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)

Ultraperipheral heavy-ion collisions (UPCs) offer unique opportunities to study processes under strong electromagnetic fields. In these collisions, highly charged fast-moving ions carry strong electromagnetic fields that can be effectively treated as photon fluxes. The exchange of photons can induce photonuclear and two-photon interactions, and excite ions. This excitation of the ions results in Coulomb dissociation with the emission of photons, neutrons, and other particles. Additionally, the electromagnetic fields generated by the ions can be sufficiently strong to enforce mutual interactions between the two colliding ions. Consequently, the two colliding ions experienced an electromagnetic force that pushed them in opposite directions, causing a back-to-back correlation in the emitted neutrons. Using a Monte Carlo simulation, we qualitatively demonstrated that the above electromagnetic effect is large enough to be observed in UPCs, which would provide a clear means to study strong electromagnetic fields and their effects.

[14] arXiv:2401.14917 (replaced) [pdf, html, other]

Title: Direct WIMP detection rates for transitions in isomeric nuclei

M.V Smirnov, G. Yang, Yu.N. Novikov, J.D. Vergados, D. Bonatsos

Subjects: High Energy Physics - Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)

The direct detection of dark matter constituents, in particular the weakly interacting massive particles (WIMPs), is central to particle physics and cosmology. In this paper we study WIMP induced transitions from isomeric nuclear states for two possible isomeric candidates: $\rm^{180}Ta$ and $\rm^{166}Ho$. The experimental setup, which can measure the possible decay of $\rm^{180}Ta$ induced by WIMPs, was proposed. The corresponding estimates of the half-life of $\rm^{180}Ta$ are given in the sense that the WIMP-nucleon interaction can be interpreted as ordinary radioactive decay.

[15] arXiv:2401.16995 (replaced) [pdf, html, other]

Title: Compton Scattering on 4He with Nuclear One- and Two-Body Densities

Harald W. Griesshammer (George Washington U.), Junjie Liao (George Washington U.), Judith A. McGovern (U. of Manchester), Andreas Nogga (FZ Jülich), Daniel R. Phillips (Ohio U.)

Comments: 38 pages LaTeX2e (pdflatex) including 13 figures as 14 .pdf files using includegraphics. Minor grammatical/typographical changes, figures 3, 4 and 7 typographically corrected without changes of substance. Text- and figure-identical to published version

Subjects: Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)

We present the first \emph{ab initio} calculation of elastic Compton scattering from 4He. It is carried out to $\mathcal{O}(e^2 \delta^3)$ [N3LO] in the $\delta$ expansion of $\chi$EFT. At this order and for this target, the only free parameters are the scalar-isoscalar electric and magnetic dipole polarisabilities of the nucleon. Adopting current values for these yields a parameter-free prediction. This compares favourably with the world data from HI$\gamma$S, Illinois and Lund for photon energies $50\;\mathrm{MeV}\lesssim\omega\lesssim120\;\mathrm{MeV}$ within our theoretical uncertainties of $\pm10\%$. We predict a cross section up to 7 times that for deuterium. As in 3He, this emphasises and tests the key role of meson-exchange currents between np pairs in Compton scattering on light nuclei. We assess the sensitivity of the cross section and beam asymmetry to the nucleon polarisabilities, providing clear guidance to future experiments seeking to further constrain them. The calculation becomes tractable by use of the Transition Density Method. The one- and two-body densities generated from 5 chiral potentials and the AV18$+$UIX potential are available using the python package provided at \url{this https URL}.

[16] arXiv:2402.14975 (replaced) [pdf, html, other]

Title: Modification of $\chi_{c1}$(3872) and $\psi$(2$S$) production in $p$Pb collisions at $\sqrt{s_{NN}} = 8.16$ TeV

LHCb collaboration: R. Aaij, A.S.W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, B. Adeva, M. Adinolfi, P. Adlarson, C. Agapopoulou, C.A. Aidala, Z. Ajaltouni, S. Akar, K. Akiba, P. Albicocco, J. Albrecht, F. Alessio, M. Alexander, A. Alfonso Albero, Z. Aliouche, P. Alvarez Cartelle, R. Amalric, S. Amato, J.L. Amey, Y. Amhis, L. An, L. Anderlini, M. Andersson, A. Andreianov, P. Andreola, M. Andreotti, D. Andreou, A. Anelli, D. Ao, F. Archilli, M. Argenton, S. Arguedas Cuendis, A. Artamonov, M. Artuso, E. Aslanides, M. Atzeni, B. Audurier, D. Bacher, I. Bachiller Perea, S. Bachmann, M. Bachmayer, J.J. Back, A. Bailly-reyre, P. Baladron Rodriguez, V. Balagura, W. Baldini, J. Baptista de Souza Leite, M. Barbetti, I. R. Barbosa, R.J. Barlow, S. Barsuk, W. Barter, M. Bartolini, F. Baryshnikov, J.M. Basels, G. Bassi, B. Batsukh, A. Battig, A. Bay, A. Beck, M. Becker, F. Bedeschi, I.B. Bediaga, A. Beiter, S. Belin, V. Bellee, K. Belous, I. Belov, I. Belyaev, G. Benane, G. Bencivenni, E. Ben-Haim, A. Berezhnoy, R. Bernet, S. Bernet Andres, H.C. Bernstein, C. Bertella, A. Bertolin, C. Betancourt, F. Betti, J. Bex, Ia. Bezshyiko, J. Bhom, M.S. Bieker, N.V. Biesuz, P. Billoir, A. Biolchini, M. Birch, F.C.R. Bishop, A. Bitadze, A. Bizzeti, M.P. Blago, T. Blake, F. Blanc, J.E. Blank

Comments: All figures and tables, along with any supplementary material and additional information, are available at this https URL (LHCb public pages)

Journal-ref: Phys. Rev. Lett. 132 (2024) 242301

Subjects: High Energy Physics - Experiment (hep-ex); Nuclear Experiment (nucl-ex)

The LHCb collaboration measures production of the exotic hadron $\chi_{c1}$(3872) in proton-nucleus collisions for the first time. Comparison with the charmonium state $\psi$(2$S$) suggests that the exotic $\chi_{c1}$(3872) experiences different dynamics in the nuclear medium than conventional hadrons, and comparison with data from proton-proton collisions indicates that the presence of the nucleus may modify $\chi_{c1}$(3872) production rates. This is the first measurement of the nuclear modification factor of an exotic hadron.

[17] arXiv:2405.04681 (replaced) [pdf, html, other]

Title: Onset of scaling violation in pion and kaon elastic electromagnetic form factors

Zhao-Qian Yao, Daniele Binosi, Craig D. Roberts

Comments: 8 pages, 5 figures, 1 table

Subjects: High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Experiment (hep-ex); High Energy Physics - Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)

Using a symmetry-preserving truncation of the quantum field equations describing hadron properties, parameter-free predictions are delivered for pion and kaon elastic electromagnetic form factors, $F_{P=\pi,K}$, thereby unifying them with kindred results for nucleon elastic electromagnetic form factors. Regarding positive-charge states, the analysis stresses that the presence of scaling violations in QCD entails that $Q^2 F_P(Q^2)$ should exhibit a single maximum on $Q^2>0$. Locating such a maximum is both necessary and sufficient to establish the existence of scaling violations. The study predicts that, for charged $\pi$, $K$ mesons, the $Q^2 F_P(Q^2)$ maximum lies in the neighbourhood $Q^2 \simeq 5\,$GeV$^2$. Foreseeable experiments will test these predictions and, providing their $Q^2$ reach meets expectations, potentially also provide details on the momentum dependence of meson form factor scaling violation.

[18] arXiv:2406.01754 (replaced) [pdf, html, other]

Title: Validating Automated Resonance Evaluation with Synthetic Data

Oleksii Zivenko, Noah A. W. Walton, William Fritsch, Jacob Forbes, Amanda M. Lewis, Aaron Clark, Jesse M. Brown, Vladimir Sobes

Comments: 39 pages, 12 figures; As a follow-up to arXiv:2303.09698 and arXiv:2402.14122

Subjects: Computational Physics (physics.comp-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th); Medical Physics (physics.med-ph)

The integrity and precision of nuclear data are crucial for a broad spectrum of applications, from national security and nuclear reactor design to medical diagnostics, where the associated uncertainties can significantly impact outcomes. A substantial portion of uncertainty in nuclear data originates from the subjective biases in the evaluation process, a crucial phase in the nuclear data production pipeline. Recent advancements indicate that automation of certain routines can mitigate these biases, thereby standardizing the evaluation process, reducing uncertainty and enhancing reproducibility. This article contributes to developing a framework for automated evaluation techniques testing, emphasizing automated fitting methods that do not require the user to provide any prior information. This approach simplifies the process and reduces the manual effort needed in the initial evaluation stage. It highlights the capability of the framework to validate and optimize subroutines, targeting the performance analysis and optimization of the fitting procedure using high-fidelity synthetic data (labeled experimental data) and the concept of a fully controlled computational experiment. An error metric is introduced to provide a clear and intuitive measure of the fitting quality by quantifying the accuracy and performance across the specified energy. This metric sets a scale for comparison and optimization of routines or hyperparameter selection, improving the entire evaluation process methodology and increasing reproducibility and objectivity.