Nuclear Experiment·nucl-ex

Thu·Jul 30, 2026Thursday·July 30, 2026

8 papers—1 primary·7 cross-listed

01
Measurement of the average transverse momentum of forward prompt charged particles in $pp$ and $p Pb$ collisions at $s_{N N} = 5.02 TeV$
LHCb collaboration: R. Aaij🇳🇱 · M. Abdelfatah🇺🇸 · A.S.W. Abdelmotteleb🇬🇧 · C. Abellan Beteta🇨🇭 · F. Abudinén🇬🇧 · T. Ackernley🇬🇧 · A.A. Adefisoye🇺🇸 · B. Adeva🇪🇸 · M. Adinolfi🇬🇧 · P. Adlarson🇵🇱 · C. Agapopoulou🇫🇷 · C.A. Aidala🇺🇸 and 1117 other authors
This letter presents the first measurements of the average transverse momentum of prompt charged particles in $pp$ and $p Pb$ collisions as a function of collision multiplicity and pseudorapidity. The data were recorded at nucleon-nucleon centre-of-mass energy $s_{N N} = 5.02 TeV$ with the LHCb experiment. The pseudorapidity dependence of the multiplicity distribution is also measured. The average transverse momentum results show a decreasing trend with pseudorapidity, more pronounced in high-multiplicity events, consistent with the collective behaviour of the produced matter. The measurements are reproduced by state-of-the-art (3+1D) hydrodynamic calculations, while saturation models are not compatible with the data.
nucl-ex0 citations
02
$^{15}$ C inelastic $1/ 2^{+} \to 5/ 2^{+}$ excitation: A single-particle versus a collective process
C. Beckman🇺🇸 · M. Catacora-Rios🇺🇸 · C. Hebborn🇺🇸 · F. M. Nunes🇺🇸
Background: The excitation of one-neutron halo nucleus $^{15}$ C from the $1/ 2^{+}$ ground state to the $5/ 2^{+}$ first excited state was measured at Argonne National Laboratory by impinging $^{15}$ C on a deuterated target at $7.1 A$ MeV. This data was then analyzed in the Distorted Wave Born Approximation using a rigid rotor model for the excitation. Purpose: Being a one-neutron halo, we expect a single-particle excitation to better represent the excitation of $^{15}$ C rather than a collective process. We expect the breakup of $^{15}$ C to influence the reaction mechanisms because of the low one-neutron separation threshold, which is close in energy to $^{15}$ C's first excited state. The goal of this work is to explore various the reaction mechanisms to reinterpret the data of Ref.[1] for the inelastic excitation of $^{15}$ C. Method: We solve the scattering problem assuming a three-body model $^{14}$ C $+ n + d$ . We use the Continuum Discretized Coupled Channel method (CDCC) and compare the results with those obtained assuming 1-step DWBA with quadrupole deformation, as done in the original experimental analysis. We also use Bayesian uncertainty quantification to estimate the uncertainties in our predictions coming from the $n$ - $d$ interaction. Results: We analyze both the elastic and inelastic angular distributions for $^{15}$ C(d,d') $^{15} C^{*}$ at $7.1 A$ MeV. Our results show that $^{15}$ C breakup effects are important. Conclusions: While CDCC predicts the elastic angular distribution correctly, it is not able to fully describe the experimental inelastic angular distribution. We discuss additional effects that may be responsible for the remaining discrepancy.
↳ nucl-thnucl-exPRC(2026)·0 citations
03
Ab initio lattice calculation of nuclear magnetic dipole moments with systematic error quantifications
Teng Wang🇨🇳 · Serdar Elhatisari🇹🇷 · Xu Feng🇨🇳 · Dean Lee🇺🇸 · Bing-Nan Lu🇨🇳 · Yuan-Zhuo Ma🇺🇸
Nuclear magnetic moments are sensitive probes of nuclear structure. However, their accurate quantitative description poses significant challenges, demanding both accurate nuclear and electromagnetic interactions as well as rigorous control of algorithmic uncertainties. Here, we present the first systematic calculation of magnetic dipole moments for selected light nuclei and aluminum isotopes within nuclear lattice effective field theory (NLEFT), an \textit{ab initio} framework applicable to medium-mass and heavy nuclei. Our calculations employ a lattice next-to-next-to-next-to-leading-order (N $^{3}$ LO) chiral interaction together with electromagnetic currents consistently derived up to the two-body level. To achieve controlled predictions, we incorporate recently developed NLEFT algorithms and perform a comprehensive assessment of algorithmic uncertainties. Within the estimated uncertainties, our results are in good overall agreement with experiment and demonstrate that two-body currents are essential for reproducing the observed magnetic moments. We further benchmark our predictions against other \textit{ab initio} calculations for light nuclei ( $A \leq 12$ ). Our work establishes a solid foundation for \textit{ab initio} studies of electroweak observables using methods that scale efficiently to medium-mass and heavy nuclei while demonstrating state-of-the-art accuracy.
↳ nucl-thhep-latnucl-ex1 citation
04
Impacts of hexadecapole correlations in actinide nuclei
L. Lotina · K. Nomura🇯🇵 · R. Rodr\'ıguez-Guzmán🇰🇿 · L. M. Robledo🇪🇸
The impact of hexadecapole correlations on the low-energy spectroscopic properties of Th, U, and Pu nuclei, within the mass range $232 \leq A \leq 240$ , is studied systematically using the mapped $s d g$ -IBM model. Fermionic input is obtained via the quadrupole-hexadecapole constrained Hartree-Fock-Bogoliubov approximation, based on the parametrization D1S of the Gogny energy density functional. The $s d g$ -IBM Hamiltonian parameters are determined by mapping the quadrupole-hexadecapole fermionic mean-field potential energy surfaces onto the corresponding bosonic surfaces. The low-energy spectra and transition strengths, obtained via the diagonalization of the $s d g$ -IBM Hamiltonian, compare well with the available experimental data. It is shown that the effects of hexadecapole collectivity can be observed in high-spin yrast states with spins $J^{π} ⩾ 1 0^{+}$ . The mapped $s d g$ -IBM improves the excitation energies of those states, as compared with the simpler $s d$ -IBM model. The $s d g$ -IBM also improves the description of the $E 2$ transition strengths between high-spin yrast states and predicts strong $E 4$ transitions from nonyrast $4^{+}$ states to the $0^{+}$ ground state.
↳ nucl-thnucl-exPRC(2026)·0 citations
05
The CROSS experiment: detector construction, background projection, and sensitivity to $^{100}$ Mo $0 ν 2 β$ decay
D. Auguste🇫🇷 · A.S. Barabash🇷🇺 · G. Benato🇮🇹 · V. Berest🇫🇷 · L. Bergé🇫🇷 · M. Buchynska🇫🇷 · J.M. Calvo-Mozota🇪🇸 · J. Cao🇫🇷 · P. Carniti🇮🇹 · M. Chapellier🇫🇷 · D. Cintas🇫🇷 · I. Cojocari🇫🇷 and 33 other authors
The CROSS experiment to search for neutrinoless double-beta ( $0 ν 2 β$ ) decay in $^{100}$ Mo with the help of an array of scintillating cryogenic calorimeters, containing 4.9 kg of $^{100}$ Mo, has been ongoing in a low-background setup at the Canfranc underground laboratory (Spain) since mid-November 2025. In this paper, we present the construction of the CROSS detector and the description of Geant4-based Monte Carlo simulations of expected background in the region of interest. The simulations predict the background index in a 100-keV-wide interval centered at the $Q$ -value of $^{100}$ Mo (3034 keV) on the level of 3.2(5) $\times$ 10 $^{- 3}$ cnts/keV/kg/yr. Taking into account an 18% deadtime induced by the muon veto cut and a typical 90% duty cycle of the facility, such background level would allow to reach the world-leading sensitivity to $^{100}$ Mo $0 ν 2 β$ decay (lim $T_{1/2} \sim 4 \times 1 0^{24}$ yr) in 1 year of data taking. Considering conservatively a factor 3 (10) worse background index due to unpredictable radioactive contamination of construction materials and/or detector performance, a 2-yr-long operation of the CROSS array would be still compatible with the best (competitive) sensitivity to $0 ν 2 β$ decay in $^{100}$ Mo.
↳ physics.ins-detnucl-ex0 citations
06
Constraining $α$ -cluster compactness in $^{16} O$ and $^{20} Ne$ at TeV energies using azimuthal anisotropy
Aswathy Menon Kavumpadikkal Radhakrishnan🇮🇳 · Suraj Prasad🇮🇳 · Neelkamal Mallick🇮🇳 · Raghunath Sahoo🇮🇳 · Gergely Gábor Barnaföldi🇭🇺
Anisotropic flow in ultra-relativistic light-ion collisions is sensitive to the initial geometry of the colliding nuclei. We investigate whether elliptic flow measurements can constrain the parameters of the proposed $α$ -clustered nuclear density distributions of $^{16}$ O and $^{20}$ Ne at LHC energies. Using the hybrid framework IP-Glasma+MUSIC+iSS+UrQMD, we simulate OO and Ne--Ne collisions at $s_{NN} = 5.36$ TeV for the Woods--Saxon and $α$ -clustered configurations with varying cluster compactness. The elliptic flow coefficient $v_{2} {2, ∣Δ η ∣ > 1}$ is calculated in the kinematic acceptances of ALICE, CMS, and ATLAS detectors and is compared with the Run~3 OO and Ne--Ne experimental measurements. It is observed that the final-state elliptic flow is significantly sensitive to the nuclear geometry, especially in OO collisions, where different configurations lead to distinct centrality dependencies and peak positions of $v_{2}$ . By performing a systematic variation of the cluster size and inter-cluster separation in $^{16}$ O and $^{20}$ Ne nuclei, this work attempts to identify the cluster parameter range that provides the best agreement with the experimental data. These results show that the flow observables in TeV-energy light-ion collisions can be used to optimize the nuclear structure parameters of light nuclei.
↳ hep-phhep-exhep-thnucl-ex+10 citations
07
Critical net-proton number fluctuations with hydrodynamics
Rui-zhe Zhao🇨🇳 · Shi Yin🇩🇪 · Shanjin Wu🇨🇳 · Lipei Du🇺🇸 · Xiaofeng Luo🇨🇳 · Wei-jie Fu🇨🇳
We compute the net-proton number fluctuations and their ratios $C_{2} / C_{1}$ , $C_{3} / C_{2}$ and $C_{4} / C_{2}$ on the hydrodynamic freeze-out hypersurface of particlization at nine collision energies, $s_{NN} = 7.7 - 200$ GeV, based on the fluctuations obtained from the functional renormalization group (fRG) approach, where both the regular and the critical fluctuations arising from the critical end point (CEP) are included. The transverse momentum and rapidity acceptance windows as same as the experimental measurements, the isospin randomization for the proton number fluctuations, and the global baryon conservation effect are implemented in the calculations. The results are also compared with the baseline results without critical fluctuations. It is found that for the low-order cumulants, e.g., $C_{2} / C_{1}$ the difference between the critical and non-critical results is small, while the difference increases with the increasing order of cumulants in the region of low collision energy. A non-monotonic dependence on the collision energy is observed in $C_{4} / C_{2}$ with critical fluctuations, which is absent in the results without critical fluctuations.
↳ nucl-thhep-phnucl-ex3 citations
08
Spectroscopic basis for short-range three-nucleon forces
Josep Solà Cava · Arseniy A. Filin🇩🇪 · Sven Heihoff🇩🇪 · Henri Paul Huesmann🇩🇪 · Evgeny Epelbaum🇩🇪
We introduce a spectroscopic basis for the subleading contact three-nucleon forces, which allows one to classify these interactions according to the total angular momentum and parity quantum numbers in a transparent way. Using this new basis, we explore the sensitivity of nucleon-deuteron observables to the three-nucleon short-range interactions. The low dimensionality of the variable-parameter space in the spectroscopic basis allows us to build a simple nucleon-deuteron scattering emulator using radial basis function interpolation. We perform exploratory fits of the subleading contact three-nucleon interactions and demonstrate that 9 of 13 low-energy constants can be reliably determined from elastic nucleon-deuteron scattering data.
↳ nucl-thhep-phnucl-ex0 citations

Affiliations

first authorsco-authorsvia INSPIRE