Nuclear Theory·nucl-th

Thursday·June 5, 2025

11 papers—2 primary·9 cross-listed

01
The influence of nuclear short range correlations on sub-threshold particle production in proton-nucleus collisions
Tom Reichert🇩🇪 · Jörg Aichelin🇩🇪
The apparent production of (multi-)strange baryons and mesons at sub-threshold energies in proton-heavy ion collisions is a consequence of short range correlations (SRC), which have recently been observed in lepton-nucleus scattering. They may enhance the available center of mass energy of individual nucleon-nucleon collisions and allow, therefore, for sub-threshold particle production in proton-nucleus collisions. Calculations demonstrate that SRC enhance the probability for particle production at nominal sub-threshold energies up to a factor of $\times 1 0^{3}$ as compared to a simple Fermi gas model. We benchmark the idea by calculating the $Ξ^{-}$ multiplicity in nominal sub-threshold p+Nb collisions which compare well with the data measured by the HADES collaboration. These findings are of prime relevance for upcoming experiments at the FAIR facility, especially for the study of charmed hadrons.
nucl-thnucl-exPLB(2026)·5 citations
02
Accessing proton number fluctuations in limited regions of phase space
Piotr Bozek🇵🇱
In heavy ion collisions particle distributions fluctuate from event to event. It is interesting to study local fluctuations of a specific particle specie, e.g. baryons, in the transverse plane. Fluctuations of the harmonic flow provide an integrated measure of such fluctuations. An alternative approach is to study proton number fluctuations measured in a relatively narrow azimuthal angle window. Due to the transverse flow, particles registered in a narrow azimuthal angle window are emitted predominantly from a region of the fireball located at the same azimuthal angle. Similarly, it is informative to measure the covariance of the number of protons emitted in two opposite windows of azimuthal angles. The main difficulty lies in distinguishing effects of local baryon density fluctuations in the transverse plane from global particle density and collective flow fluctuations. These global volume and flow fluctuations can be estimated using some reference particles, e.g. charged mesons. Reliable estimates of such fluctuations can be constructed both for the second factorial cumulant of the proton number in an azimuthal angle window and for the covariance between two such windows. The simultaneous measurement of both quantities provides a sensitive probe of local baryon number fluctuations superimposed on top of a fluctuating fireball background density.
nucl-thhep-phnucl-exPRC(2026)·0 citations
03
Extremely large oblate deformation of the first excited state in $^{12}$ C: a new challenge to modern nuclear theory
C. Ngwetsheni🇿🇦 · J. N. Orce🇿🇦 · P. Navrátil🇨🇦 · P. E. Garrett🇿🇦 · T. Faestermann🇩🇪 · A. Bergmaier🇩🇪 · M. Frosini🇫🇷 · V. Bildstein🇨🇦 · B. A. Brown🇺🇸 · C. Burbadge🇨🇦 · T. Duguet🇫🇷 · K. Hadyńska-Klȩk and 5 other authors
A Coulomb-excitation study of the high-lying first excited state at 4.439 MeV in the nucleus $^{12}$ C has been carried out using the $^{208}$ Pb( $^{12}$ C, $^{12}$ C $^{*}$ ) $^{208}$ Pb $^{*}$ reaction at 56 MeV and the {\sc Q3D} magnetic spectrograph at the Maier-Leibnitz Laboratorium in Munich. High-statistics achieved with an average beam intensity of approximately 10 $^{11}$ ions/s together with state-of-the-art {\it ab initio} calculations of the nuclear dipole polarizability permitted the accurate determination of the spectroscopic quadrupole moment, $Q_{_{S}} (2_{_{1}}^{+}) = + 0.076 (30)$ ~eb, in agreement with previous measurements. Combined with previous work, a weighted average of $Q_{_{S}} (2_{_{1}}^{+}) = + 0.090 (14)$ eb is determined, which includes the re-analysis of a similar experiment by Vermeer and collaborators, $Q_{_{S}} (2_{_{1}}^{+}) = + 0.103 (20)$ ~eb. Such a large oblate deformation challenges modern nuclear theory and emphasizes the need of $α$ clustering and associated triaxiality effects for full convergence of $E 2$ collective properties.
↳ nucl-exnucl-thphysics.data-an1 citation
04
Reducing Hadronic Uncertainty in Low-Energy Neutral-Current Processes
Oleksandr Tomalak🇨🇳
We analyze the hadronic uncertainty from light-quark loops coupled to (anti)neutrino in low-energy neutral-current (anti)neutrino scattering, estimated at the $3$ - $4$ permille level. This uncertainty arises from limited knowledge of the charge-isospin correlation function of quark currents. We study the charge-charge and charge-isospin correlators within $SU (2)$ and $SU (3)$ chiral perturbation theory (ChPT). In $SU (2)$ ChPT, the two correlators are identical to all orders in the chiral and electromagnetic expansions. We further perform a leading-order $SU (3)$ ChPT calculation and discuss the relevant counterterms. Our findings reduce the hadronic uncertainty in neutral-current processes such as (anti)neutrino-electron and coherent elastic (anti)neutrino-nucleus scattering by a factor $\sim 35$ .
↳ hep-phhep-exnucl-exnucl-thPLB(2026)·3 citations
05
Modelling Coincident Particle Production in Ultraperipheral Heavy Ion Collisions
L. A. Harland-Lang🇬🇧
In this paper, we present an analysis of coincident particle production in ultraperipheral heavy ion collisions. In particular, we present the first detailed and differential predictions for coincident $ρ^{0}$ meson production in association with muon pair production, motivated by the recent ATLAS measurement of this process. These are found to describe the data very well, including the dependence of the coincidence fraction on the ZDC selection and/or other kinematic constraints on the muons. Differential predictions at the level of various kinematic variables are presented, and the calculation is made publicly available in the SuperChic MC generator. We also present general results for coincident two-photon initiated production focussing on muon and electron pair production; while the former is rather suppressed, the latter will be ubiquitous at threshold. The impact of coincident production on exclusivity vetos in ultraperipheral measurements is in addition discussed.
↳ hep-phhep-exnucl-exnucl-thPRD(2025)·3 citations
06
$f$ -mode oscillations in hot Neutron Stars: Effect of hyperons and neutrino trapping
Nilaksha Barman🇮🇳 · Debarati Chatterjee🇮🇳
In this work, we present an equation of state formalism for hot Neutron Stars (NSs) which consistently includes the effects of finite temperature, hyperons as well as neutrino trapping, relevant for the study of proto-neutron stars, binary neutron star mergers and supernova explosions. Within a non-linear relativistic mean field description, the framework allows for a systematic variation of nuclear parameters within the range allowed by uncertainties in nuclear experimental data, ensuring compatibility with nuclear theory, astrophysical and heavy-ion data. We then investigate the role of nuclear and hypernuclear parameters as well as thermal effects on NS macroscopic properties and $f$ -mode oscillations in hot neutron stars within Cowling approximation. Our results reveal that in hyperonic neutron stars with trapped neutrinos, the saturation nuclear density shows moderate to strong correlation with NS astrophysical observables. We also investigate whether thermal effects break universal relations and provide fit relations for hot NS configurations in the neutrino-trapped regime.
↳ astro-ph.HEnucl-thMNRAS(2025)·4 citations
07
Permutation-Invariant N-body gates via Tavis-Cummings Hamiltonian
Plato Deliyannis🇺🇸 · Iman Marvian🇺🇸
Global control provides a promising route to implementing multi-qubit gates without individual qubit addressing. This is especially appealing for permutation-invariant (PI) gates, whose symmetry is often broken when they are compiled into individually addressed one- and two-qubit gates. Important examples include SWAP, $i SWAP$ , and the n-qubit controlled-Z gate, which is equivalent, up to two single-qubit Hadamard gates, to the multi-qubit Toffoli gate. Motivated by this global-control perspective, we show that all PI unitaries on an arbitrary number of qubits can be realized using the Tavis-Cummings (TC) interaction, the multi-qubit version of the Jaynes-Cummings interaction, together with global uniform z and x fields. Here, the $n$ qubits are identically coupled to a single bosonic mode (oscillator), which is initialized in and returned to its vacuum state. A corollary is that all PI states, including GHZ and Dicke states, can be prepared using the same global control. For the case n=2 qubits, which is particularly important in quantum computing, we also find explicit pulse sequences for implementing all PI qubit unitaries that conserve angular momentum in the z direction, using only the TC interaction and global z fields. This includes controlled-Z, SWAP, and $i SWAP$ .
↳ quant-phmath-phmath.MPnucl-th+21 citation
08
Off-shell ambiguities in correlation functions: strategies to minimize them
R. Molina🇪🇸 · E. Oset🇪🇸
We face here the problem of uncertainties in correlation functions due to the freedom in the off-shell dependence of the wave functions, or equivalently, off-shell ambiguities in the scattering matrices. We make the study for the case of meson baryon interaction, choosing the $K Λ$ , $K Σ$ , $η N$ coupled channels, which are related to the $N^{*} (1535)$ resonance. We find that using realistic interactions based on chiral dynamics the uncertainties are small, of the order of $2 - 3$ ~\%, but could be much bigger if other methods are used. However, our study shows the way to optimally overcome these uncertainties in the analysis of correlation functions, and we provide a series of recommendations for any general analysis.
↳ hep-phnucl-thPRD(2025)·16 citations
09
Event Topology Classifiers at the Large Hadron Collider
Suraj Prasad🇮🇳 · Sushanta Tripathy🇸🇪 · Bhagyarathi Sahoo🇮🇳 · Raghunath Sahoo🇮🇳
Event classifiers are the most fundamental observables to probe the event topology of hadronic and nuclear collisions at relativistic energies. Over the last five decades, significant progress has been made to establish suitable event classifiers to probe different physics processes occurring in elementary $e^{+} e^{-}$ to heavy-ion collisions in a broad range of center of mass energies. One of the major motivations to revisit event classifiers at the Large Hadron Collider (LHC) originates from the recent measurements of high multiplicity proton-proton collisions, which have revealed that these small collision systems exhibit features similar to the formation of quark-gluon plasma (QGP), traditionally believed to be only achievable in heavy nucleus-nucleus collisions at ultra-relativistic energies. To pinpoint the origin of these QGP-like phenomena with substantially reduced autocorrelation and selection biases, and to bring all collision systems on equal footing, along with charged-particle multiplicity, lately several event topology classifiers such as transverse sphericity, transverse spherocity, relative transverse activity classifier, and charged-particle flattenicity have been used extensively in experiments as well as in the phenomenological front. In addition, the infrared and collinear safety of event-shape observables makes them ideal for precision studies of jets and heavy-flavors at the LHC. In this review article, we summarise the motivation, scope, and practical use of these event-shape observables. The discussion integrates results and insights from all major LHC experiments, setting the stage for precision investigations for Run 3, Run 4, and future high luminosity upgrades of the LHC.
↳ hep-phhep-exhep-thnucl-ex+1Phys.Rept.(2026)·17 citations
10
Improved superscaling description of electron and charged-current neutrino quasielastic scattering using effective mass dynamics
V.L. Martinez-Consentino🇪🇸 · P.R. Casale🇪🇸 · J.E. Amaro🇪🇸
We present an improved version of the Superscaling Analysis with Relativistic Effective Mass, denoted as SuSAM-v2. In the original SuSAM model, a universal scaling function was fitted to a selected set of quasielastic electron scattering (e,e') cross section data, using a phenomenological ansatz inspired by the Relativistic Mean Field model of nuclear matter. In this work, we refine the procedure by first fitting a longitudinal scaling function directly to experimental longitudinal response data. Subsequently, a separate transverse scaling function is extracted from purely transverse data, after subtracting the longitudinal contribution already determined. We find that the resulting transverse scaling function must exhibit an explicit dependence on the momentum transfer q in order to reproduce all kinematics consistently. The resulting SuSAM-v2 model simultaneously describes inclusive quasielastic cross sections and both longitudinal and transverse response functions in electron scattering. The model is then applied to neutrino-nucleus scattering, showing an improved prediction compared to the previous SuSAM-v1 version, due to a more accurate treatment of the relative contributions of the longitudinal and transverse weak nuclear responses.
↳ hep-phnucl-thPRD(2025)·2 citations
11
The Infrared Phase of QCD and Anderson Localization
Ivan Horváth🇨🇿
When Anderson localization entered the QCD landscape, it was almost immediately thought about in connection with thermal phases, namely as a factor in the chiral transition. However, recent developments revealed an additional structure that made Anderson-like features central to the genesis of the entirely new thermal phase: the IR phase. I will explain these developments.
↳ hep-latcond-mat.dis-nnhep-phnucl-thPoS(2025)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE