#1 TBD
Isabella Danhoni (UIUC)
#2 Low-Energy Expansion from Operator Product Expansion in asymptotically free theories with a mass gap
Hajime Furuta (Tohoku University)
Perturbative expansions become ineffective in the low-energy region of asymptotically free theories such as QCD, where important nonperturbative phenomena including color confinement and hadron mass generation arise. Recently, Takaura [1] proposed a method to obtain low-energy limits of physical observables in asymptotically free theories with a mass gap using the operator product expansion (OPE) and analytic properties of observables. In this framework, the Borel transform relates the low-energy expansion to the OPE constructed in the high-energy region, while this reconstruction requires duality-violation (DV) contributions arising from differences in analytic structure between the exact observable and the OPE. This previous work obtained only the leading low-energy expansion coefficient through a weight function independent of the detail of observables. Here we extend this framework and show that low-energy expansion coefficients at arbitrary order can be obtained by systematically deriving the weight functions and explicitly incorporating DV contributions. We also discuss the interplay between DV terms and the asymptotic behavior of the OPE, and explicitly verify the method in the two-dimensional nonlinear sigma model. [1]Hiromasa Takaura. “Low energy limit from high energy expansion in mass gapped theory”. In: JHEP 10 (2024), p. 085. doi: 10.1007/JHEP10(2024)085. arXiv: 2404.05589 [hep-th].
#3 Chiral symmetry restoration and hyperon suppression in neutron stars
Bikai Gao (RCNP, Osaka University)
The ``hyperon puzzle'' remains a fundamental challenge in nuclear astrophysics. We investigate hyperon emergence in neutron star matter using the $SU(3)$ parity doublet model with chiral representation $(3,\bar{3}) + (\bar{3},3)$. This framework naturally incorporates chiral symmetry restoration and provides a systematic description of baryon masses in dense matter through the interplay between the chiral condensate and the chiral invariant mass $m_0$. We find that the hyperon onset density exhibits strong sensitivity to $m_0$: for $m_0 = 500$ MeV, hyperons first appear at $1.9n_0$ while for $m_0 \gtrsim 750$ MeV, hyperons emerge only above $5n_0$. This delayed onset arises from the weakened density dependence of baryon masses at larger $m_0$ values. When the hyperon onset density exceeds the expected quark-hadron transition range ($2$--$5n_0$), matter undergoes deconfinement before hyperons populate, avoiding the EoS softening while maintaining consistency with massive neutron star observations. Our results demonstrate that chiral dynamics provides a natural resolution to the hyperon puzzle without requiring ad hoc repulsive hyperon interactions.
#4 Fluctuations of conserved charges with Mobius Domain Wall fermions
Jishnu Goswami (Bielefeld University)
#5 TBD
Asanosuke Jinno (KEK)
#6 Chiral phase transition with 2+1 flavor lattice QCD simulation at physical point with Moebius domain wall fermion
Issaku Kanamori (RIKEN)
We report on our results from physical point simulations with 2+1 flavor Moebius domain wall fermion at finite temperature. The temperature range is around 140 MeV to 250 MeV with the temporal lattice size Nt=12 and 16. In the high temperature phase, we also have some additional data with a coarser lattice, Nt=10.
#7 Heavy dense QCD and three state Potts model with complex phase
Masanari Koiida (Niigata University)
Heavy dense QCD is thought to have the same phase structure as the three-state Potts model with complex phase. We use Monte Carlo simulations to determine the critical point and study the phase structure. The duality between high density and low density is important in our study.
#8 Magnetic-type Love number differentiating quark stars from neutron stars
Josuke Minamiguchi (The University of Tokyo)
The quark star (QS) is a hypothetical and yet undiscovered stellar object, and its existence would mark a paradigm shift in research on nuclear and quark matter. Although compactness is a well-known signature for distinguishing between two branches of QSs and neutron stars (NSs), some QSs can overlap with NSs in the radius-mass plane. To manifest their evident differences, we investigate the tidal properties of QSs and NSs. We then find that the magnetic-type Love number is a robust indicator for differentiating between QSs and NSs, whereas the electric-type one is insufficient when QSs and NSs have similar masses and radii. Finally, we show that gravitational waves from binary star mergers can be sensitive to differences between QSs and NSs to the detectable level.
#9 Statistical repulsion and hyperon onset in two-color dense QCD
Masato Nagatsuka (Tohoku University)
We argue that quark saturation induces statistical repulsion among nucleons and hyperons, shifting the onset of hyperons to higher densities.
#10 F-mode Oscillations of Neutron Stars with Hyperons, Sexaquarks, and Quark Matter
Davood Rafiei Karkevandi (University of Wroclaw, Institute of Theoretical Physics)
We study the effects of hyperons, sexaquarks, and the phase transition to quark matter on the fundamental (f-mode) oscillations of neutron stars. The sexaquark is considered as a hypothetical six-quark state and a possible dark matter candidate. Adopting hybrid equations of state with a smooth hadron-quark crossover, we explore how the f-mode frequencies and damping times change as new phases are introduced into the stellar interior. By comparing nucleonic, hyperonic, sexaquark-admixed, and hybrid configurations, we isolate the effect of each additional degree of freedom on the oscillation spectrum. We further show that, for the hybrid stars containing hyperons, sexaquarks, and quark matter, the associated quasi-universal relations remain tight and effectively insensitive to the detailed composition, despite requiring higher-order fits in some cases. These results suggest that future f-mode observations may offer a new way to probe exotic matter and quark deconfinement in neutron star interiors.
#11 Continuity in dense 2 flavor QCD?
Conan Sakamoto (YITP)
#12 Phase Transition to Deconfined Quark Matter in Neutron Stars with Hyperons and Bosonic Dark Matter
Mahboubeh Shahrbaf (University of Wrocław)
Phase transitions in dense matter play a key role in determining the structure and observable properties of neutron stars. In this work, I explore a hybrid framework that includes hyperonic matter, bosonic dark matter in the form of sexaquarks, and deconfined quark matter. The transition from hadronic to quark matter is modeled as a smooth crossover, enabling a consistent description across different density regimes. Using Bayesian inference with current observational constraints, I place constraints on the mass of the dark matter particle and analyze how bosonic dark matter affects the equation of state (EoS). The results show that the inclusion of such components softens the EoS while remaining compatible with observational data, highlighting the potential of neutron star observations to probe both phase transitions and exotic degrees of freedom in dense matter.
#13 Tensor renormalization group approach for (3+1)d finite density QCD at strong coupling limit
Yuto Sugimoto (Tohoku University)
We investigate the phase structure of finite density QCD in (3+1) dimensions in the strong coupling limit. At finite temperature, we study the critical endpoints of the chiral and nuclear transitions. We also present results at zero temperature.
#14 Chemical Potential Dependence of the Gluon Screening Mass in QC2D at Finite Density
Kei Tohme (Kyoto University)
#15 Lattice Study of Roberge–Weiss Tricritical Point in Heavy-Quark Region
Tatsuya Wada (Kyoto University/YITP)
The order of the phase transition in QCD is known to depend on the quark mass and the baryon chemical potential. In the heavy-quark limit and at μ/T=iπ/3, the first-order Roberge–Weiss transition line terminates at a triple first-order point where three first-order lines intersect. As the quark mass decreases, this triple point is expected to terminate at a tricritical point. In the present study, we aim to determine the location of the tricritical point of the Roberge-Weiss transition in the heavy-quark region in lattice QCD simulations. The simulations are performed using the hopping parameter expansion, which enables high-statistics analysis. The Binder cumulant and several other quantities are used to locate the tricritical point and determine its critical exponents.
#16 Numerical study of partial deconfinement in QCD (TBA)
Hiromasa Watanabe (Keio University)
The confinement/deconfinement phase transition in gauge theories at finite temperature has been extensively studied for many years. Analyses in the large-$N_c$ limit reveal several nontrivial nonperturbative features of this transition. In particular, it has been argued that three (or more) distinct phases exist, separated by large-$N_c$ transitions, and characterized by Polyakov loops in various representations, i.e., by the gauge degrees of freedom. In this presentation, we provide numerical evidence for such phases in several models beyond the weak-coupling regime. We also discuss the applicability of the large-$N$ picture to $\mathrm{SU}(3)$ QCD with fundamental quarks using actual lattice QCD ensembles.
#17 Hadron Thermodynamics in positively curved spacetime
Sho Yoshida (University of Tokyo)
We investigate thermodynamic quantities of hadrons moving in the Einstein static spacetime and de Sitter spacetime to see the effect of curvature and horizon on the thermodynamics of strongly intercting matter.
#18 TBD
Gregoire Pihan (University of Houston)