Nuclear Theory·nucl-th

Thursday·April 16, 2026

9 papers—2 primary·7 cross-listed

03
[Submitted on 14 Apr 2026] (cross-list from hep-ph)
Proton Structure from Neural Simulation-Based Inference at the LHC
Ricardo Barrué🇦🇹 · Lisa Benato🇦🇹 · Ali Kaan Güven🇦🇹 · Elie Hammou🇳🇱 · Jaco ter Hoeve🇬🇧 · Claudius Krause🇦🇹 · Ang Li🇦🇹 · Luca Mantani🇪🇸 · Juan Rojo🇳🇱 · Sergio Sánchez Cruz🇪🇸 · Robert Schöfbeck🇦🇹 · Maria Ubiali🇬🇧 · Daohan Wang🇦🇹
The precise determination of the parton distribution functions (PDFs) of the proton is an essential ingredient for LHC analyses, including for those at the upcoming High-Luminosity LHC. So far, PDFs are determined from global fits to binned low-dimensional data obtained from unfolded hard-scattering cross section measurements. In this work we demonstrate for the first time the feasibility of neural simulation-based inference (NSBI) for constraining the proton PDFs using a high-dimensional unbinned data set. Exploiting the full statistical power of unbinned data removes the loss of information inherited by the binning procedure. As a proof-of-concept, we determine the gluon PDF from simulated data of top quark pair production at the LHC with $s = 13$ TeV. Taking into account both experimental and theoretical systematic uncertainties in the detector-level features, we demonstrate how the NSBI pipeline achieves significant improvements in precision compared to existing low-dimensional binned analyses. Our results illustrate the potential of unbinned inference to reduce the reliance on coarse approximations of uncertainties and their correlations entering PDF determinations, hence contributing to a new paradigm of unbinned detector-level ML-assisted measurements at the LHC.
Comments:
57 pages, 24 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2604.13157 [pdf]
3 citations
04
[Submitted on 15 Apr 2026] (cross-list from quant-ph)
Quantum computing for effective nuclear lattice model
Zhushuo Liu🇨🇳 · Jia-ai Shi🇨🇳 · Bing-Nan Lu🇨🇳 · Xiaosi Xu🇨🇳
Nuclear lattice effective field theory has become an important framework for quantum many-body calculations in nuclear physics, yet its classical implementation remains increasingly challenging for more general interactions and larger systems. In this work, we develop a quantum-computing framework for a three-dimensional nuclear lattice model. We construct a variational quantum eigensolver framework and systematically compare the Jordan-Wigner and Gray code encodings. Our analysis shows that for the few-body systems considered here, Gray code combined with symmetry reduction yields a substantially more compact qubit representation. Based on this framework, we perform numerical studies for $^{2} H$ , $^{3} H$ , and $^{4} He$ on finite lattices. The calculated ground-state energies exhibit a clear approach toward the corresponding experimental binding energies as the lattice size increases. These results provide a proof-of-principle foundation for future quantum simulations of nuclear many-body problems.
Comments:
9 pages, 3 figures and 1 table
Subjects:
Quantum Physics (quant-ph); Nuclear Theory (nucl-th)
arXiv:
2604.13430 [pdf]
0 citations
05
[Submitted on 15 Apr 2026] (cross-list from quant-ph)
Response theory for quantum fields in isolation
Stefan Floerchinger🇩🇪
Response theory describes the reaction of observales to perturbations in external fields. We review this formalism for quantum fiels in isolation that have unitary time evolution. An emphasis is put on consequences of causality and the resulting spectral representations for linear and nonlinear response functions, on functional techniques and generating functionals, including the description of the initial state, the evolution, and measurements. We review consequences of time reversal symmetry and relations for the statistics of work, and discuss a large class of quantum correlation functions, and their relation to response functions through fluctuation-dissipation relations. Consequences of conservation laws and gauge symmetries are mentioned briefly.
Comments:
56 pages, 2 figures
Subjects:
Quantum Physics (quant-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2604.13637 [pdf]
1 citation
06
[Submitted on 15 Apr 2026] (cross-list from hep-ph)
Global polarization of $Λ$ hyperons in hot QCD matter at TeV energies
Bhagyarathi Sahoo🇮🇳 · Captain R. Singh🇮🇳 · Raghunath Sahoo🇮🇳
The study of spin polarization of $Λ$ hyperons in ultrarelativistic heavy-ion collisions provides insights into the angular momentum and vortical structure of the possible existence of QGP. The present study examines the global spin polarization of $Λ$ hyperons using a second-order relativistic viscous hydrodynamic framework that incorporates medium vorticity, shear viscosity, and evolving magnetic fields. It explores thermal vorticity evolution in relativistic heavy-ion collisions and evaluates its value at the decoupling isothermal freeze-out surface. We quantify the contributions of thermal vorticity and magnetic field to the global spin polarization of $Λ$ hyperons. Comparing results with recent ALICE measurements in Pb+Pb collisions at $s_{N N}$ = 2.76 and 5.02 TeV shows qualitative agreement, offering new insights into the vortical structure of QCD matter. It also explores the relationship between magnetic and rotational dynamics, with implications for spin polarization at RHIC and LHC energies.
Comments:
10 pages and 2 captioned figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Theory (hep-th); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2604.13701 [pdf]
1 citation
07
[Submitted on 15 Apr 2026] (cross-list from nucl-ex)
Spectroscopy of $^{11}$ Be from the $^{10}$ Be( $d, p$ ) reaction measured in inverse kinematics by the AT-TPC in SOLARIS
M. Z. Serikow · D. Bazin · M. A. Caprio · Y. Ayyad · S. Beceiro-Novo · J. Chen · M. Cortesi · M. DeNudt · S. Giraud · P. Gueye · S. Heinitz · C. R. Hoffman and 12 other authors
The spectroscopy of $^{11}$ Be is explored using the $^{10}$ Be $(d, p)$ $^{11}$ Be transfer reaction performed in inverse kinematics at $9.6 \MeV / u$ using the Active Target Time Projection Chamber (AT-TPC) inside the SOLARIS solenoid. This experiment is the first attempt at coupling the AT-TPC with SOLARIS to perform a high luminosity transfer reaction measurement without compromising excitation energy and scattering angle resolutions. The angular momentum transfer for states up to $3.40 \MeV$ are determined from distorted-wave Born approximation analysis of the measured angular distributions, from which the corresponding spectroscopic factors are deduced. These factors are compared with those from various shell model interactions, and those for the $3.40 \MeV$ state are consistent with a positive parity assignment. Recent \textit{ab initio} no-core configuration interaction (NCCI) calculations with various nucleon-nucleon interactions are presented for the low-lying positive parity states of $^{11}$ Be. The excitation energies produced using the Daejeon16 interaction are in good agreement with those found from both this experiment and the literature, thus supporting a positive parity assignment. The $3.40 \MeV$ state, if assigned a tentative $J^{π} = 3/ 2^{+}$ , would then correspond to the second excited state of the $K^{P} = 1/ 2^{+}$ one-neutron halo ground state rotational band also predicted from such NCCI calculations.
Comments:
11 pages, 7 figures
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2604.13766 [pdf]
0 citations
08
[Submitted on 15 Apr 2026] (cross-list from hep-ph)
Fully Heavy Pentaquarks with JETHAD: A High-Energy Viewpoint
Francesco Giovanni Celiberto🇪🇸
We examine the leading-power fragmentation of fully heavy pentaquarks in high-energy hadronic collisions. To this end, we complete the release of the hadron-structure-oriented PQ5Q1.0 fragmentation functions, by discussing the $P_{5 c}$ set and delivering the $P_{5 b}$ one. These functions incorporate an improved computation of the initial-scale input for the constituent heavy-quark fragmentation channel, making them particularly suitable for describing both the direct formation of a compact multicharm state and the hadronization from a diquark-antiquark-diquark configuration. For phenomenological applications, we employ the data-validated (sym)JETHAD framework to compute and analyze NLL/NLO $^{+}$ semi-inclusive production rates of pentaquark-plus-jet systems at the upcoming HL-LHC and the future FCC. This study marks a further step toward connecting hadronic structure, precision QCD, and the emerging physics of exotic matter.
Comments:
49 pages, 8 figures, 595 references. Invited review article. Chapter IV of the review pentalogy "Heavy hadrons with JETHAD: A high-energy viewpoint"
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Theory (hep-th); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2604.13769 [pdf]
Particles(2026)·6 citations
09
[Submitted on 15 Apr 2026] (cross-list from hep-ph)
AI-assisted modeling and Bayesian inference of unpolarized quark transverse momentum distributions from Drell-Yan data
Zhong-Bo Kang🇺🇸 · Luke Sellers🇺🇸 · Congyue Zhang🇺🇸 · Curtis Zhou🇺🇸
We present an extraction of unpolarized quark transverse-momentum-dependent parton distribution functions (TMD PDFs) from Drell-Yan data within a Bayesian inference framework, incorporating artificial intelligence at multiple stages of the analysis. Our analysis is performed at $N^{3} LO$ in perturbative QCD combined with $N^{4} LL$ resummation accuracy. We first employ an AI-driven iterative procedure to explore and rank candidate functional forms for the nonperturbative contributions to TMD PDFs at the initial scale, as well as for the Collins-Soper evolution kernel, using $χ^{2}$ fits and physics constraints. To enable efficient Bayesian inference, we construct a surrogate model for TMD cross sections by training a machine-learning emulator over the parameter space, replacing computationally expensive repeated evaluations and allowing scalable sampling with an affine-invariant Markov Chain Monte Carlo (MCMC) ensemble. Using this framework, we perform a global analysis of Drell-Yan data from fixed-target, RHIC, and LHC experiments and extract TMD PDFs with quantified uncertainties. We compare the results with those obtained using the replica method and highlight differences in the resulting uncertainty estimates.
Comments:
48 pages, 14 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2604.14133 [pdf]
5 citations

Affiliations

first authorsco-authorsvia INSPIRE

Proton Structure from Neural Simulation-Based Inference at the LHC

Quantum computing for effective nuclear lattice model

Response theory for quantum fields in isolation

Global polarization of Λ hyperons in hot QCD matter at TeV energies

Spectroscopy of 11Be from the 10Be(d,p) reaction measured in inverse kinematics by the AT-TPC in SOLARIS

Fully Heavy Pentaquarks with JETHAD: A High-Energy Viewpoint

AI-assisted modeling and Bayesian inference of unpolarized quark transverse momentum distributions from Drell-Yan data

Affiliations

Global polarization of $Λ$ hyperons in hot QCD matter at TeV energies

Spectroscopy of $^{11}$ Be from the $^{10}$ Be( $d, p$ ) reaction measured in inverse kinematics by the AT-TPC in SOLARIS