Nuclear Theory·nucl-th

Tuesday·March 28, 2023

18 papers—9 primary·9 cross-listed

10
Phenomenology of double deeply virtual Compton scattering in the era of new experiments
K. Deja🇵🇱 · V. Martinez-Fernandez🇵🇱 · B. Pire🇫🇷 · P. Sznajder🇵🇱 · J. Wagner🇵🇱
We revisit the phenomenology of the deep exclusive electroproduction of a lepton pair, i.e. double deeply virtual Compton scattering (DDVCS), in view of new experiments planned in the near future. The importance of DDVCS in the reconstruction of generalized parton distributions (GPDs) in their full kinematic domain is emphasized. Using Kleiss-Stirling spinor techniques, we provide the leading order complex amplitudes for both DDVCS and Bethe-Heithler sub-processes. Such a formulation turns out to be convenient for practical implementation in the PARTONS framework and EpIC Monte Carlo generator that we use in simulation studies.
↳ hep-phhep-exnucl-exnucl-thPRD(2023)·53 citations
11
Centrality-dependent modification of hadron and jet production in electron-nucleus collisions
Hai Tao Li🇨🇳 · Ze Long Liu🇨🇭 · Ivan Vitev🇺🇸
Centrality-dependent measurements of hadron and jet cross section attenuation in deep inelastic scattering on nuclei can shed new light on the physics of final-state interactions in the nuclear matter, including the path-length dependence of the in-medium parton shower formation and evolution. Recent simulation studies have demonstrated the feasibility of experimental centrality determination in $e$ A reactions at the electron-ion collider via neutron detection in the zero-degree calorimeter. Motivated by these results, we present the first theoretical calculation of the production rate modification for hadrons and jets in central and peripheral $e$ Pb collisions. We find that the variation in the suppression of inclusive jet cross section as a function of centrality is less than a factor of two. In more differential measurements, such as the distribution of hadrons versus the hadronization fraction $z_{h}$ , the difference can be enhanced up to an order of magnitude.
↳ hep-phnucl-thPLB(2024)·8 citations
12
SU(2) Gauge Theory in $2 + 1$ Dimensions on a Plaquette Chain Obeys the Eigenstate Thermalization Hypothesis
Xiaojun Yao🇺🇸
We test the eigenstate thermalization hypothesis (ETH) for 2+1 dimensional SU(2) lattice gauge theory. By considering the theory on a chain of plaquettes and truncating basis states for link variables at $j = 1/2$ , we can map it onto a quantum spin chain with local interactions and numerically exactly diagonalize the Hamiltonian for reasonably large lattice sizes. We find energy level repulsion in momentum sectors with no remaining discrete symmetry. We study two local observables made up of Wilson loops and calculate their matrix elements in the energy eigenbasis, which are shown consistent with the ETH.
↳ hep-latcond-mat.stat-mechhep-phnucl-th+1PRD(2023)·48 citations
13
Chiral symmetry breaking and the masses of hadrons: a review
Su Houng Lee🇰🇷
The masses of hadrons in the vacuum, where the chiral symmetry is restored, and in the medium are in general different even when the changes in the order parameters of chiral symmetry are the same. Here, we first discuss the relation between the hadron masses and the chiral symmetry breaking in approaches based on operator product expansion (OPE). We then discuss what additional changes occur to the hadron masses when going from the chiral symmetry restored vacuum to nuclear medium and/or finite temperature. The work will highlight how we can identify the effects of chiral symmetry restoration from experimental observations.
↳ hep-phnucl-exnucl-thSymmetry(2023)·18 citations
14
New derivation of Time-Independent Perturbation Theory
A. N. Kvinikhidze · B. Blankleider
We propose a new derivation of Time-Independent Perturbation Theory (PT) that has a fundamental advantage over the usual derivations presented in textbooks on Quantum Mechanics (QM): it is simpler and much shorter. As such, it can provide an easier and quicker way for students to learn PT, than afforded by current methods. In spite of that, our approach does not require the potentials to be energy independent or the inverse free Green function $G_{0}^{- 1} (E)$ to be a linear function of energy $E$ , as is the case in QM, and can be applied directly to various extensions of QM including Relativistic QM, the Bethe-Salpeter equation, and all kinds of quasipotential approaches in Quantum Field Theory.
↳ quant-phhep-phhep-thnucl-th0 citations
15
Universal tetramer limit-cycle at the unitarity limit
Tobias Frederico🇧🇷 · Mario Gattobigio🇫🇷
We demonstrate that a four-boson limit-cycle independent of the Efimov one appears in Hamiltonian systems at the unitary limit. The model interaction contains two-, three- and four-body short-range potentials, which disentangle the interwoven three- and four-boson cycles, for the universal trimer and tetramer energy levels, respectively. The limit-cycle associated with the correlation between the energies of two successive universal tetramer levels for fixed weakly bound trimer is found to be largely model independent. This is a universal manifestation of an independent four-boson scale associated with a cycle beyond the Efimov one.
↳ physics.atm-clusnucl-thquant-phPRA(2023)·4 citations
16
Exact Excited-State Functionals of the Asymmetric Hubbard Dimer
Sara Giarrusso · Pierre-François Loos
The exact functionals associated with the (singlet) ground and the two singlet excited states of the asymmetric Hubbard dimer at half-filling are calculated using both Levy's constrained search and Lieb's convex formulation. While the ground-state functional is, as commonly known, a convex function with respect to the density (or, more precisely, the site occupation), the functional associated with the (highest) doubly-excited state is found to be concave. Also, because the density of the first-excited state is non-invertible, its ``functional'' is a partial, multi-valued function composed of one concave and one convex branch that correspond to two separate sets of values of the external potential. Remarkably, it is found that, although the one-to-one mapping between density and external potential may not apply (as in the case of the first excited state), each state-specific energy and corresponding universal functional are ``functions'' whose derivatives are each other's inverse, just as in the ground state formalism. These findings offer insight into the challenges of developing state-specific excited-state density functionals for general applications in electronic structure theory.
↳ cond-mat.str-elcond-mat.mtrl-scimath-phmath.MP+2J.Phys.Chem.Lett.(2023)·9 citations
17
Exploring QCD matter in extreme conditions with Machine Learning
Kai Zhou🇩🇪 · Lingxiao Wang🇩🇪 · Long-Gang Pang🇨🇳 · Shuzhe Shi🇺🇸
In recent years, machine learning has emerged as a powerful computational tool and novel problem-solving perspective for physics, offering new avenues for studying strongly interacting QCD matter properties under extreme conditions. This review article aims to provide an overview of the current state of this intersection of fields, focusing on the application of machine learning to theoretical studies in high energy nuclear physics. It covers diverse aspects, including heavy ion collisions, lattice field theory, and neutron stars, and discuss how machine learning can be used to explore and facilitate the physics goals of understanding QCD matter. The review also provides a commonality overview from a methodology perspective, from data-driven perspective to physics-driven perspective. We conclude by discussing the challenges and future prospects of machine learning applications in high energy nuclear physics, also underscoring the importance of incorporating physics priors into the purely data-driven learning toolbox. This review highlights the critical role of machine learning as a valuable computational paradigm for advancing physics exploration in high energy nuclear physics.
↳ hep-phastro-ph.HEhep-exhep-lat+1PPNP(2024)·121 citations
18
Charmoniumlike tetraquarks in a chiral quark model
Gang Yang🇨🇳 · Jialun Ping🇨🇳 · Jorge Segovia🇪🇸
The lowest-lying charmonium-like tetraquarks $c c ˉ q q ˉ$ $(q = u, d)$ and $c c ˉ s s ˉ$ , with spin-parity $J^{P} = 0^{+}$ , $1^{+}$ and $2^{+}$ , and isospin $I = 0$ and $1$ , are systematically investigated within the theoretical framework of complex-scaling range for a chiral quark model that has already been successfully applied in former studies of various tetra- and penta-quark systems. A four-body $S$ -wave configuration which includes meson-meson, diquark-antidiquark and K-type arrangements of quarks, along with all possible color wave functions, is comprehensively considered. Several narrow resonances are obtained in each tetraquark channel when a fully coupled-channel computation is performed. We tentatively assign theoretical states to experimentally reported charmonium-like signals such as $X (3872)$ , $Z_{c} (3900)$ , $X (3960)$ , $X (4350)$ , $X (4685)$ and $X (4700)$ . They can be well identified as hadronic molecules; however, other exotic components which involve, for instance, hidden-color channels or diquark-antidiquark structures play a considerable role. Meanwhile, two resonances are obtained at $4.04$ GeV and $4.14$ GeV which may be compatible with experimental data in the energy interval $4.0 - 4.2$ GeV. Furthermore, the $X (3940)$ and $X (4630)$ may be identified as color compact tetraquark resonances. Finally, we also find few resonance states in the energy interval from $4.5$ GeV to $5.0$ GeV, which would be awaiting for discovery in future experiments.
↳ hep-phhep-exhep-latnucl-ex+1EPJC(2023)·14 citations

Affiliations

first authorsco-authorsvia INSPIRE