arXiv subjects

Sungsik Noh

Publications and source records attributed to Sungsik Noh.

10 recordsLinked to original sources

arXiv2026

Three-body forces in the quark model

We review the connection between constituent-quark Hamiltonians and QCD and investigate the long-standing difficulty of describing meson and baryon spectra with one common two-body interaction. A Hamiltonian calibrated to ground-state mesons leaves systematic baryon mass residuals, largest in the light-quark sector and decreasing toward heavier flavors. We show that a short-range, color-spin-dependent connected three-quark interaction substantially reduces this incompatibility. Mass-scaled finite-range profiles yield high-accuracy baryon spectra, whereas flavor-independent common-range profiles do not remove the residual flavor pattern. The result is tested on additional ground-state baryons outside the calibration set and through meson--baryon compatibility analyses across several alternative quark-model Hamiltonians. We also benchmark radial and orbital excitations to identify the regime in which a static compact valence Hamiltonian remains reliable, and provide explicit color-spin matrix elements for two- and three-body operators in baryons and multiquark configurations. Within the tested valence-space representations, the results indicate that a mass-dependent short-range connected three-quark interaction provides the missing contribution required for a consistent simultaneous description of meson and baryon ground-state spectra.

hep-ph↗

arXiv2026

The structure of the $X(3915)$ meson and its production in heavy ion collisions

We study the structure of the $X(3915)$ meson in a quark model and explore how its production in heavy ion collisions depends on its internal structure. We first analyze the $X(3915)$ as a $c\bar{c}s\bar{s}$ state and solve the Hamiltonian with color-spin interactions within the quark model. We find that the ground state of the $c\bar{c}s\bar{s}$ with total spin 0 obtained from the quark model analysis favors a separated $D_s \bar{D}_s$ state. To probe its structure further, we study its production in relativistic heavy ion collisions for various proposed configurations. We calculate the transverse momentum distributions and yields for the $X(3915)$ assuming its structure to be either a charmonium, a tetraquark, or a hadronic molecular state. We argue that by measuring the transverse momentum distributions and yields of the $X(3915)$ produced in heavy ion collisions, one can identify the structure of the $X(3915)$.

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arXiv2024

The Inevitable Quark Three-Body Force and its Implications for Exotic States

Three-body nuclear forces are essential for explaining the properties of light nuclei with a nucleon number greater than three. Building on insights from nuclear physics, we extract the form of quark three-body interactions and demonstrate that these terms are crucial for extending the quark model fit of the meson spectrum to include baryons using the same parameter set. We then discuss the implications of our findings for exotic configurations involving more than three quarks, such as the $T_{cc}$ and $χ_{c1}(3872)$. We find that the quark three-body interactions provide additional repulsion on the order of 10 MeV for the compact configurations of both the $T_{cc}$ and $χ_{c1}(3872)$. This result, combined with previous calculations, strongly suggests that these tetraquark states are molecular rather than compact states.

hep-ph↗

arXiv2024

Investigation on the stabilities of doubly heavy tetraquark states

In our recent work\cite{Noh:2023zoq}, the mass and binding energy of $T_{cc}$ are found to be $3873$ MeV and $-2$ MeV, respectively, which align with the observations reported at LHCb\cite{LHCb:2021vvq}. Based on our latest quark model approach, we extend our search for other potentially stable configurations of doubly heavy tetraquarks using our nonrelativistic quark model described in Ref.~\cite{Noh:2023zoq}. Our numerical calculations indicate that the $\bar{u}\bar{s}cb$ configuration is deeply bound. However, the $\bar{u}\bar{d}cb$ configuration with the isospin symmetry in the light quark sector is relatively less bound. In this study, we emphasize a compulsory aspect for requiring a complete set of three dimensional harmonic oscillator bases through the discussion of the $\bar{u}\bar{s}cb$ configuration and investigate the essential differences between the $\bar{u}\bar{s}cb$ and $\bar{u}\bar{d}cb$ configurations.

hep-ph↗

arXiv2024

Diquarks and the production of charmed baryons

Utilizing a quark model characterized by parameters that effectively replicate the masses of ground state hadrons, we illustrate that $(us)$ or $(ds)$ diquarks exhibit greater compactness in comparison to $(ud)$ diquarks. Concretely, the binding energy of the $(us)$ diquark - defined as the diquark's mass minus the combined masses of its individual quarks - is found to be stronger than that of the $(ud)$ diquark. This heightened attraction present in $(us)$ diquarks could lead to enhanced production of $Ξ_c/D$ particles in high-energy pp or ultrarelativistic heavy-ion collisions.

hep-ph↗

arXiv2023

The doubly-charmed pentaquark in a quark model with a complete set of harmonic oscillator bases

As our recent quark model calculation~\cite{Noh:2023fdy} suggests a strong possibility of a compact $T_{cc}$ that closely reproduces experimental mass, we have a strong incentive to extend our work to investigate the possible compact configuration of a pentaquark $udcc\bar{s}$, which is related to the structure of the doubly charmed tetraquark $T_{cc}$. Since the introduction of a complete set of 3-dimensional harmonic oscillator bases to a spatial wave function in solving a quark model-based Hamiltonian with variational method leads to a more accurate value of the mass, it seems natural that future studies of the pentaquark should be treated with the same elaborate technical approach. To attain such precision for the ground state energy, we utilize a complete set of 3-dimensional harmonic oscillator base up to 6th quanta. Before carrying out this process, one important thing that has to be taken into account is to find out the color $\otimes$ spin states of the pentaquark for the evaluation of color and spin interaction most essential to the quark model configuration. To easily identify the suitable configuration, we make a systematic analysis of $SU(6)_{CS}$ irreducible representation of the pentaquark, from which we find that there is a correspondence between the color $\otimes$ spin states obtained from their coupling scheme and the multiplet of the $SU(6)_{CS}$ irreducible representation of the pentaquark. We find that the energy of the pentaquark configuration is +18.5 MeV above the lowest threshold for decay into $Ξ_{cc}$ and $K$, suggesting that this configuration is not stable against its decay. Nonetheless, while we used a Gaussian hyperfine potential, it was recently found that a Yukawa form leads to a stronger attraction for the $T_{cc}$ configuration. Therefore it is important to study the same configuration using the latter potential.

hep-ph↗

arXiv2023

Observation of $T_{cc}$ and a quark model

The recent discovery of the doubly charmed tetraquark $T_{cc}$ ($\bar{u}\bar{d}cc$) provides a stringent constraint on its binding energy relative to its lowest decay threshold. We use a fully convergent spatial wave function and perform a simultaneous global fit to both the meson and baryon spectra. Our analysis shows that a Yukawa type hyperfine potential leads to a slight bound state for $T_{cc}$ with $(I,S) = (0,1)$ below its lowest threshold, in agreement with recent experimental findings. We also find that $T_{cc}$ is highly likely to be in a compact configuration.

hep-ph↗

arXiv2022

$X(3872)$ and $T_{cc}$: structures and productions in heavy ion collisions

We argue why the recently observed $T_{cc}$ could either be a compact multiquark configuration or a loosely bound molecular configuration composed of charmed mesons, whereas the $X(3872)$ is most likely a molecular configuration. The argument is based on different short range interactions for these tetraquark states coming from the color-color and color-spin interaction in a quark model, and the presence of a common strong D-wave mixing at larger distance similar to the deuteron case, which for the molecular configurations lead to large sizes. Such an analogy at large distance allows us to calculate the transverse momentum dependence of the loosely bound molecular configuration of tetraquarks produced in heavy ion collisions using the coalescence model that successfully reproduces the deutron data using the proton spectra. The ratio of the integrated $X(3872)$ yield obtained from our method to the $ψ(2S)$ yield obtained from statistical hadronization model method is calculated to be $0.806 \pm 0.234$, which is a factor of 2.47 larger than that obtained by using statistical model predictions for both particles and in line with the data from the CMS experiment. As the previously calculated transverse momentum distribution of the $T_{cc}$ assuming the structure to be a compact multiquark configuration is markedly different, experimental measurements of the transverse distribution of the tetraquark states will discriminate between their two possible structures.

hep-ph↗

arXiv2021

The Doubly-heavy Tetraquarks ($qq'\bar{Q}\bar{Q'}$) in a Constituent Quark Model with a Complete Set of Harmonic Oscillator Bases

We have improved our previous variational method based constituent quark model by introducing a complete set of 3-dimensional harmonic oscillator bases as the spatial part of the total wave function. To assess the validity of our approach, we compared the binding energy, thus calculated with the exact value for the hydrogen model. After fitting to the masses of the ground state hadrons, we apply our new method to analyze the doubly-heavy tetraquark states $qq'\bar{Q}\bar{Q'}$ and compared the result for the binding energies with that from other works. We also calculated the ground state masses of $T_{sc} (ud\bar{s}\bar{c})$ and $T_{sb} (ud\bar{s}\bar{b})$ with $(I,S) = (0,1), (0,2)$. We found that $T_{bb} (ud\bar{b}\bar{b})$ and $us\bar{b}\bar{b}$, both with $(I,S) = (0,1)$, are stable against the two lowest threshold meson states with binding energies $-145$ MeV and $-42$ MeV, respectively. We further found that $T_{cb} (ud\bar{c}\bar{b})$ is near the lowest threshold. The spatial sizes for the tetraquarks are also discussed.

hep-ph↗

arXiv2018

Masses of the doubly heavy tetraquarks in a constituent quark model

We perform a constituent quark model analysis for the masses of the doubly heavy tetraquark states $T_{QQ}$ after we fix the parameters to fit the masses of the newly observed $Ξ_{cc}^{++}$ and hadrons involving heavy quarks relevant to the stability of these states. We investigate in detail how the relative distances between quark pairs vary as we change the quark content and how they affect the various contributions to the total tetraquark masses. We also find that our full calculations give in general less binding compared to simplified quark model calculations that treat quark dynamics inside the tetraquark the same as that inside a baryon. We trace the main origin to be the differences in the number of relative kinetic energies which increases as one goes from meson, baryon and tetraquarks. We also compare our new results with previous works using less constrained parameters and find that the tetraquark state $T_{bb}(ud\bar{b}\bar{b})$ and $T_{bb}(us\bar{b}\bar{b})$ are bound by 120.56 MeV and 7.3 MeV respectively.

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