Nuclear Theory·nucl-th

Monday·October 2, 2023

13 papers—7 primary·6 cross-listed

01
Isospectral Potentials and Quantum Mechanical Functions for Neutron-Neutron Scattering
Anil Khachi
In this paper we have constructed inverse isospectral potentials for 1S0-nn state by fitting the experimental SPS using Variational Monte-Carlo technique in tandem with PFM technique. The isospectral potentials are obtained such that the cost measure i.e., mean absolute error (MAE) between the obtained and experimental SPS are less than 1 and the parameters give the low energy scattering parameters (`a' and `re') very close to the experimental values. The S-channel SPS for 1S0-nn have been obtained, with a MAE with respect to experimental data for lab energies up to 350 MeV, to less than 1.
nucl-th2 citations
02
A Bayesian study of quark models in view of recent astrophysical constraints
Franciele M. da Silva🇧🇷 · Adamu Issifu🇧🇷 · Luiz L. Lopes🇧🇷 · Luis C. N. Santos🇵🇰 · Débora P. Menezes🇧🇷
In this work, we perform a comparative analysis between the density-dependent quark model and the vector MIT bag model using Bayesian analysis. We use the equations of state generated by these two models to describe quark stars. We impose four recent observational astrophysical constraints on both models to determine their model-dependent parameters in an optimized manner assuming that the compact objects observed are composed entirely of self-bound quarks. The restrictions are aimed at producing stars with maximum masses $2 - 2.35$ M $_{⊙}$ and a mass-radii diagram compatible with the observed pulsars: PSR J0740+6620, PSR J0952-0607, PSR J0030+0451 and the compact object XMMU J173203.3-344518. With this analysis, the parameter dependence of the nuclear equation of state (EoS) of both models is restricted.
nucl-thPRD(2024)·15 citations
03
Nucleonic Shells and Nuclear Masses
Landon Buskirk · Kyle Godbey · Witold Nazarewicz · Wojciech Satula
The binding energy of an isotope is a sensitive indicator of the underlying shell structure as it reflects the net energy content of a nucleus. Since magic nuclei are significantly lighter, or more bound, compared to their neighbors, the presence of nucleonic shell structure makes an imprint on nuclear masses. In this work, using a carefully designed binding-energy indicator, we catalog the appearance of spherical and deformed shell and subshell closures throughout the nuclear landscape. After presenting experimental evidence for shell and subshell closures as seen through the lens of nuclear masses, we study the ability of global nuclear mass models to predict local binding-energy variations related to shell effects.
nucl-thnucl-exPRC(2024)·15 citations
04
Data-driven reevaluation of $f t$ -values in superallowed $β$ decays
Chien-Yeah Seng🇺🇸 · Mikhail Gorchtein🇩🇪
We present a comprehensive re-evaluation of the $f t$ values in superallowed nuclear $β$ decays crucial for the precise determination of $V_{u d}$ and low-energy tests of the electroweak Standard Model. It consists of the first, fully data-driven analysis of the nuclear $β$ decay form factor, that utilizes isospin relations to connect the nuclear charged weak distribution to the measurable charge distributions. This prescription supersedes previous shell-model estimations, and allows for a rigorous quantification of theory uncertainties in $f$ which is absent in the existing literature. Our new evaluation shows an overall downward shift of the central values of $f$ at the level of 0.01\%.
nucl-thhep-exhep-phnucl-exPRC(2024)·25 citations
05
Possible inconsistency between phenomenological and theoretical determinations of charge symmetry breaking in nuclear energy density functionals
Tomoya Naito · Gianluca Colò · Tetsuo Hatsuda · Haozhao Liang · Xavier Roca-Maza · Hiroyuki Sagawa
We summarize the recent progress on the determination of the charge symmetry breaking term of nuclear energy density functionals. We point out that the strength of the term determined theoretically is remarkably smaller than that determined phenomenologically, which is still an open question.
nucl-thnucl-exNuovo Cim.C(2024)·3 citations
06
Nuclear Modification Factor in Pb-Pb and p-Pb collisions at $s_{N N}$ =5.02 TeV at LHC energies using Boltzmann Transport Equation with Tsallis Blast Wave Description
Aditya Kumar Singh🇮🇳 · Aviral Akhil🇮🇳 · Swatantra Kumar Tiwari🇮🇳 · Pooja Pareek🇮🇳
In this article, we have studied the nuclear modification factor measured in Pb-Pb collisions ( $R_{P b P b}$ ) for $π^{\pm}$ , $K^{\pm}$ , $p + p ˉ$ , $K^{* 0} + K^{* 0} ˉ$ , $ϕ$ and in p-Pb collisions ( $R_{pP b}$ ) for $π^{\pm}$ , $K^{\pm}$ , $p + p ˉ$ at Large hadron collider (LHC) energy of $s_{N N}$ = 5.02 TeV for the most central and peripheral collisions. We have also analysed the experimental data of transverse momentum ( $p_{T}$ ) spectra for these identified hadrons at LHC for Pb-Pb as well as for p-Pb collisions. We have used Boltzmann transport equation (BTE) in relaxation time approximation (RTA) for this analysis. The Tsallis statistics is used as an initial distribution function and The Tsallis blast wave (TBW) model is employed as an equilibrium distribution in BTE. The present model fits the measured transverse momentum spectra, $R_{P b P b}$ , and $R_{pP b}$ successfully upto $p_{T}$ = 8 GeV with a reasonable $χ^{2} / n df$ for all the considered hadrons at various centralities. The experimental data for $R_{pP b}$ are generated using the particle yields at pPb and pp collisions where number of binary collisions are taken from Glauber model calculations. We find that the average transverse flow velocity ( $< β_{r} >$ ) follows the mass and centrality ordering and decreases with the mass as well as when one move from the central collisions to peripheral collisions. These findings are inline with the results of the hydrodynamical calculations.
nucl-thhep-exhep-phnucl-exEur.Phys.J.Plus(2024)·5 citations
07
Properties of charge-exchange giant spin-dipole resonances in medium-heavy closed-shell parent nuclei: a semimicroscopic description
V. I. Bondarenko · M. Y. Urin
The semimicroscopic particle-hole dispersive optical model is adapted for a description of main properties of charge-exchange giant spin-multipole resonances in medium-heavy closed-shell parent nuclei. The adapted model is implemented to evaluating the strength functions, transition densities, and branching ratios of direct one-nucleon decay for charge-exchange giant spin-dipole resonances in the ^{48}Ca, ^{90}Zr, ^{132}Sn, and ^{208}Pb parent nuclei. Some of calculation results are compared with available experimental data.
nucl-thPRC(2024)·3 citations
08
Diquarks and $Λ^{0} / π^{+}$ , $Ξ^{-} / π^{+}$ ratios in the framework of the EPNJL model
A. V. Friesen🇷🇺 · Yu. L. Kalinovsky🇷🇺
The applicability of the effective models to the description of baryons and the behaviour of ratios of strange baryons to pions is discussed. In the framework of the EPNJL model, the Bethe - Salpeter equation is used to find masses of baryons, which are considered as diquark-quark state. Baryon melting is discussed at a finite chemical potential and a flavor dependence of the hadronic deconfinement temperature is pointed. It is shown that the description of the diquark-quark state at finite chemical potential is limited due to the occurrence of the Bose condensate. This effect is strongly manifested in the description of light diquarks and baryons. Both $Λ^{0} / π^{+}$ and $Ξ^{-} / π^{+}$ ratios show a sharp behaviour as functions of $T / μ_{B}$ variable, where T and $μ_{B}$ are calculated along the melting lines.
↳ hep-phnucl-thParticles(2023)·1 citation
09
Extraction of the neutron F2 structure function from inclusive proton and deuteron deep-inelastic scattering data
Shujie Li🇺🇸 · Alberto Accardi🇺🇸 · Matteo Cerutti🇺🇸 · Ishara. P. Fernando🇺🇸 · Cynthia E. Keppel🇺🇸 · Wally Melnitchouk🇺🇸 · Peter Monaghan🇺🇸 · Gabriel Niculescu🇺🇸 · Maria I. Niculescu🇺🇸 · Jeff. F. Owens🇺🇸
The available world deep-inelastic scattering data on proton and deuteron structure functions F2p, F2d, and their ratios, are leveraged to extract the free neutron F2n structure function, the F2n/F2p ratio, and associated uncertainties using the latest nuclear effect calculations in the deuteron. Special attention is devoted to the normalization of the proton and deuteron experimental datasets and to the treatment of correlated systematic errors, as well as the quantification of procedural and theoretical uncertainties. The extracted F2n dataset is utilized to evaluate the Q2 dependence of the Gottfried sum rule and the nonsinglet F2p - F2n moments. To facilitate replication of our study, as well as for general applications, a comprehensive DIS database including all recent JLab 6 GeV measurements, the extracted F2n, a modified CTEQ-JLab global PDF fit named CJ15nlo_mod, and grids with calculated proton, neutron and deuteron DIS structure functions at next-to-leading order, are discussed and made publicly available.
↳ hep-phhep-exnucl-exnucl-thPRD(2024)·16 citations
10
Energy minimization of paired composite fermion wave functions in the spherical geometry
Greg J. Henderson · Gunnar Möller · Steven H. Simon
We perform the energy minimization of the paired composite fermion (CF) wave functions, proposed by Möller and Simon (MS) [PRB 77, 075319 (2008)] and extended by Yutushui and Mross (YM) [PRB 102, 195153 (2020)], where the energy is minimized by varying the CF pairing function, in the case of an approximate model of the Coulomb interaction in the second Landau level for pairing channels $ℓ = - 1, 3, 1$ which are expected to be in the Pfaffian, anti-Pfaffian and particle-hole symmetric (PH) Pfaffian phases respectively. It is found that the energy of the $ℓ = - 1$ MS wave function can be reduced substantially below that of the Moore-Read wave function at small system sizes, however, in the $ℓ = 3$ case the energy cannot be reduced much below that of the YM trial wavefunction. Nonetheless, both our optimized and unoptimized wavefunctions with $ℓ = - 1, 3$ extrapolate to roughly the same energy per particle in the thermodynamic limit. For the $ℓ = 1$ case, the optimization makes no qualitative difference and these PH-Pfaffian wave functions are still energetically unfavourable. The effective CF pairing is analyzed in the resulting wave functions, where the effective pairing for the $ℓ = - 1, 3$ channels is found to be well approximated by a weak-pairing BCS ansatz and the $ℓ = 1$ wave functions show no sign of emergent CF pairing.
↳ cond-mat.str-elnucl-thPRB(2023)·3 citations
11
Near-threshold resonance in $e^{+} e^{-} \to Λ_{c} Λ ˉ_{c}$ process
S.G. Salnikov🇷🇺 · A.I. Milstein🇷🇺
We discuss the influence of various contributions of the $Λ_{c} Λ ˉ_{c}$ potential on the energy dependence of the cross section $e^{+} e^{-} \to Λ_{c} Λ ˉ_{c}$ near the threshold. New BESIII experimental data on the cross section and electromagnetic form factors $G_{E}$ and $G_{M}$ are taken into account. Our predictions are in good agreement with experimental data. We predict a bound state of $Λ_{c} Λ ˉ_{c}$ at energy $\sim 38 MeV$ below the threshold that may manifest itself in anomalous behavior of light meson production cross sections in a given energy region.
↳ hep-phhep-exnucl-thPRD(2023)·13 citations
12
Doubly heavy tetraquark states in the constituent quark model using diffusion Monte Carlo method
Yao Ma🇨🇳 · Lu Meng🇩🇪 · Yan-Ke Chen🇨🇳 · Shi-Lin Zhu🇨🇳
We use the diffusion Monte Carlo method to calculate the doubly heavy tetraquark $T_{cc}$ system in two kinds of constituent quark models, the pure constituent quark model AL1/AP1 and the chiral constituent quark model. When the discrete configurations are complete and no spatial clustering is preseted, the AL1/AP1 model gives an energy of $T_{cc}$ close to the $D D^{*}$ threshold, and the chiral constituent quark model yields a deeply bound state. We further calculate all doubly heavy tetraquark systems with $J^{P} = 0^{+}, 1^{+}, 2^{+}$ , and provide the binding energies of systems with bound states. The $I (J^{P}) = 0 (0^{+})$ $b c n ˉ n ˉ$ , $0 (1^{+})$ $bb n ˉ n ˉ$ , $0 (1^{+})$ $b c n ˉ n ˉ$ , $\frac{1}{2} (1^{+})$ $bb s ˉ n ˉ$ systems have bound states in all three models. Since the DMC method has almost no restriction on the spatial part, the resulting bound states have greater binding energies than those obtained in previous works.
↳ hep-phhep-exhep-latnucl-thPRD(2024)·30 citations
13
An algebraic model to study the internal structure of pseudo-scalar mesons with heavy-light quark content
B. Almeida-Zamora🇲🇽 · J.J. Cobos-Martínez🇲🇽 · A. Bashir🇲🇽 · K. Raya🇪🇸 · J. Rodríguez-Quintero🇪🇸 · J. Segovia🇪🇸
The internal structure of all lowest-lying pseudo-scalar mesons with heavy-light quark content is studied in detail using an algebraic model that has been applied recently, and successfully, to the same physical observables of pseudo-scalar and vector mesons with hidden-flavor quark content, from light to heavy quark sectors. The algebraic model consists on constructing simple and evidence-based \emph{ansätze} of the meson's Bethe-Salpeter amplitude (BSA) and quark's propagator in such a way that the Bethe-Salpeter wave function (BSWF) can then be readily computed algebraically. Its subsequent projection onto the light front yields the light front wave function (LFWF) whose form allows us a simple access to the valence-quark Parton Distribution Amplitude (PDA) by integrating over the transverse momentum squared. We exploit our current knowledge of the PDAs of lowest-lying pseudo-scalar heavy-light mesons to compute their Generalized Parton Distributions (GPDs) through the overlap representation of LFWFs. From these three dimensional knowledge, different limits/projections lead us to deduce the related Parton Distribution functions (PDFs), Electromagnetic Form Factors (EFFs), and Impact parameter space GPDs (IPS-GPDs). When possible, we make explicit comparisons with available experimental results and earlier theoretical predictions.
↳ hep-phhep-exhep-latnucl-ex+1PRD(2024)·20 citations

Affiliations

first authorsco-authorsvia INSPIRE