Mon·Dec 26, 2022Monday·December 26, 2022

1. 01*

   Novel Bottomonium Results

   Ben Page🇬🇧 · Chris Allton🇬🇧 · Seyong Kim🇰🇷

   We present the latest results from the use of the Backus-Gilbert method for reconstructing the spectra of NRQCD bottomonium mesons using anisotropic FASTSUM ensembles at non-zero temperature. We focus in particular on results from the ${\eta }_b$, ${\rm Y}$, ${\chi }_{b1}$ and $h_b$ generated from Tikhonov-regularized Backus-Gilbert coefficient sets. We extend previous work on the Laplace shifting theorem as a means of resolution improvement and present new results from its use. We conclude with a discussion of the limitations of the improvement routine and elucidate a connection with Parisi-Lepage statistical scaling.

   hep-latPoS(2023)·3 citations
2. 02*

   Complex Langevin boundary terms in full QCD

   Michael W. Hansen🇦🇹 · Dénes Sexty🇦🇹

   Lattice simulations of non-zero density QCD introduce the so-called sign problem (complex or negative probabilities), which invalidates importance sampling methods. To circumvent this, we use the Complex Langevin Equation (CLE), to measure the boundary terms and then compare these results with the ones gotten from reweighting, confirming the expectations from previous studies. We also investigate boundary terms in simulations using CLE with dynamic stabilization and compare this, to results calculated with reweighting.

   hep-latPoS(2023)·5 citations
3. 03*

   Calculating the QED correction to the hadronic vacuum polarisation on the lattice

   Gaurav Ray🇬🇧 · Alexei Bazavov🇺🇸 · Christine Davies🇬🇧 · Carleton DeTar🇺🇸 · Aida El-Khadra🇺🇸 · Steven Gottlieb🇺🇸 · Daniel Hatton🇬🇧 · Hwancheol Jeong🇺🇸 · Andreas Kronfeld🇺🇸 · Shaun Lahert🇺🇸 · Peter Lepage🇺🇸 · Craig McNeile🇬🇧 · James Simone🇺🇸 · Alejandro Vaquero Avilés-Casco🇺🇸

   Isospin-breaking corrections to the hadron vacuum polarization component of the anomalous magnetic moment of the muon are needed to ensure the theoretical precision of $g_{\mu }-2$ is below the experimental precision. We describe the status of our work calculating, using lattice QCD, the QED correction to the light and strange connected hadronic vacuum polarization in a Dashen scheme. We report results using physical $N_f=2+1+1$ HISQ ensembles at three lattice spacings and three heavier-than-light valence quark masses.

   hep-latPoS(2023)·8 citations
4. 04*

   Study of Hadron Masses with Faddeev-Popov Eigenmode Projection in the Coulomb Gauge

   Hiroki Ohata🇯🇵 · Hideo Suganuma🇯🇵

   Using SU(3) lattice QCD, we investigate role of spatial gluons for hadron masses in the Coulomb gauge, considering the relation between QCD and the quark model. From the Coulomb-gauge configurations at the quenched level on a $16^3\times 32$ lattice at $\beta$ = 6.0, we consider the $\vec{A}=0$ projection, where all the spatial gluon fields are set to zero. In this projection, the inter-quark potential is unchanged. We investigate light hadron masses and find that nucleon and delta baryon masses are almost degenerate. This result suggests that the N-$\Delta$ mass difference arises from the color-magnetic interactions, which is consistent with the quark model picture. Next, as a generalization of this projection, we expand spatial gluon fields in terms of Faddeev-Popov eigenmodes and leave only some partial components. We find that the $\mathrm{N}-\Delta$ and $0^{++}-2^{++}$ glueball mass splittings are almost reproduced only with 1 \% low-lying components. This suggests that low-lying color-magnetic interaction leads to the hadron mass splitting.

   hep-lathep-phEPJ Web Conf.(2022)·0 citations
5. 05*

   Low energy effective theories on the lattice with coloured noise

   Felipe Attanasio🇩🇪 · Jan Philipp Klinger🇩🇪 · Jan M. Pawlowski🇩🇪

   Low energy effective theories give access to regimes of the QCD phase diagram that to date are hard to simulate directly with lattice QCD or with functional approaches. For lattice QCD this includes the small temperature and/or large density regime. In both regimes the lower UV cutoff in low energy effective theories may soften computational problems. Moreover, lattice results for low energy effective theories serve as benchmark results for functional approaches for these effective theories. Here we present lattice results for the scalar O($4$) and quark-meson models. We simulate the theory via Stochastic Quantisation and report on the effects of employing coloured noise, a method that allows control over the momentum scale of the simulation.

   hep-latPoS(2023)·1 citation
6. 06*

   Study of charm and beauty in QGP from unquenched lattice QCD

   Sajid Ali🇩🇪 · Dibyendu Bala🇩🇪 · Olaf Kaczmarek🇩🇪 · Hai-Tao Shu🇩🇪 · Tristan Ueding🇩🇪

   We present charmonium and bottomonium correlators and corresponding reconstructed spectral functions from full QCD calculations in the pseudoscalar channel. Correlators are obtained using a mixed-action approach, clover-improved Wilson valence quarks on gauge field configurations generated with $N_f=2+1$ HISQ sea quarks, with physical strange quark masses and light quark masses corresponding to $m_{\pi }=315$ MeV. The charm and bottom quark masses are tuned to reproduce the experimental mass spectrum of the spin averaged quarkonium vector mesons from the particle data group. For the spectral reconstruction, we use models based on perturbative spectral functions from different frequency regions like resummed thermal contributions around the threshold from pNRQCD and vacuum contributions well above the threshold. We show preliminary results of the reconstructed spectral function obtained for the first time in our study for full QCD.

   hep-latPoS(2023)·1 citation
7. 07*

   Implications of gradient flow on the static force

   Nora Brambilla🇩🇪 · Viljami Leino🇩🇪 · Julian Mayer-Steudte🇩🇪 · Antonio Vairo🇩🇪

   We use gradient flow to compute the static force based on a Wilson loop with a chromoelectric field insertion. The result can be compared on one hand to the static force from the numerical derivative of the lattice static energy, and on the other hand to the perturbative calculation, allowing a precise extraction of the ${\Lambda }_0$ parameter. This study may open the way to gradient flow calculations of correlators of chromoelectric and chromomagnetic fields, which typically arise in the nonrelativistic effective field theory factorization.

   hep-lathep-thnucl-thPoS(2023)·5 citations
8. 08*

   Lattice calculation of the R-ratio smeared with Gaussian kernel

   Constantia Alexandrou🇨🇾 · Simone Bacchio🇨🇾 · Alessandro De Santis🇮🇹 · Petros Dimopoulos🇫🇷 · Jacob Finkenrath🇨🇾 · Roberto Frezzotti🇮🇹 · Giuseppe Gagliardi🇮🇹 · Marco Garofalo🇩🇪 · Kyriakos Hadjiyiannakou🇨🇾 · Bartosz Kostrzewa🇩🇪 · Karl Jansen🇩🇪 · Vittorio Lubicz🇮🇹 and 6 other authors

   The ratio $R(E)$ of the cross-sections for $e^{+}{e}^{-}\to$ hadrons and $e^{+}{e}^{-}\to {\mu }^{+}{\mu }^{-}$ is a valuable energy-dependent probe of the hadronic sector of the Standard Model. Moreover, the experimental measurements of $R(E)$ are the inputs of the dispersive calculations of the leading hadronic vacuum polarization contribution to the muon $g-2$ and these are in significant tension with direct lattice calculations and with the muon $g-2$ experiment. In this talk we discuss the results of our first-principles lattice study of $R(E)$. By using a recently proposed method for extracting smeared spectral densities from Euclidean lattice correlators, we have calculated $R(E)$ convoluted with Gaussian kernels of different widths $\sigma$ and central energies up to $2.5$ GeV. Our theoretical results have been compared with the KNT19 [1] compilation of experimental results smeared with the same Gaussian kernels and a tension (about three standard deviations) has been observed for $\sigma \sim 600$ MeV and central energies around the $\rho$-resonance peak.

   hep-lathep-phPoS(2023)·5 citations
9. 09*

   Modeling the resonance $T_{cs0}^a(2900{)}^{++}$ as a hadronic molecule $D^{\ast +}{K}^{\ast +}$

   S. S. Agaev🇦🇿 · K. Azizi🇮🇷 · H. Sundu🇹🇷

   The doubly charged scalar resonance $T_{cs0}^a(2900{)}^{++}$ is studied in the context of the hadronic molecule model. We consider $T_{cs0}^a(2900{)}^{++}$ as a molecule $M=D^{\ast +}{K}^{\ast +}$ composed of vector mesons, and calculate its mass, current coupling and full width. The spectroscopic parameters of $M$, i.e., its mass and current coupling, are found by means of the QCD two-point sum rule method by taking into account vacuum expectation values of quark, gluon and mixed operators up to dimension $10$. The width of the molecule $M$ is evaluated through the calculations of the partial widths of the decay channels $M\to D_s^{+}{\pi }^{+}$, $M\to D_s^{\ast +}{\rho }^{+}$, and $M\to D^{\ast +}{K}^{\ast +}$. Partial widths of these processes are determined by strong couplings $g_1$, $g_2$, and $g_3$ of particles at vertices $M{D}_s^{+}{\pi }^{+}$, $M{D}_s^{\ast +}{\rho }^{+}$, and $M{D}^{\ast +}{K}^{\ast +}$ , respectively. We calculate the couplings $g_i$ by employing the QCD light-cone sum rule approach and technical tools of the soft-meson approximation. Predictions obtained for the mass $m=(2924\pm 107)\mathrm{MeV}$ and width $\Gamma =(123\pm 25)\mathrm{MeV}$ of the hadronic molecule $M$ allow us to consider it as a possible candidate of the resonance $T_{cs0}^a(2900{)}^{++}$.

   ↳ hep-phhep-exhep-latPRD(2023)·36 citations
10. 10*

    A new look at the $P_{cs}$ states from a molecular perspective

    Albert Feijoo🇪🇸 · Wen-Fei Wang🇨🇳 · Chu-Wen Xiao🇨🇳 · Jia-Jun Wu🇨🇳 · Eulogio Oset🇪🇸 · Juan Nieves🇪🇸 · Bing-Song Zou🇨🇳

    We have a look at the $P_{cs}$ states generated from the interaction of ${\bar{D}}^{(\ast )}{\Xi }_c^{(\prime \ast )}$ coupled channels. We consider the blocks of pseudoscalar-baryon $({\frac{1}{2}}^{+},{\frac{3}{2}}^{+})$ and vector-baryon $({\frac{1}{2}}^{+},{\frac{3}{2}}^{+})$, and find $10$ resonant states coupling mostly to $\bar{D}{\Xi }_c,{\bar{D}}^{\ast }{\Xi }_c,\bar{D}{\Xi }_c^{\prime },{\bar{D}}^{\ast }{\Xi }_c^{\prime },\bar{D}{\Xi }_c^{\ast }$ and ${\bar{D}}^{\ast }{\Xi }_c^{\ast }$. A novel aspect of the work is the realization that the $\bar{D}{\Xi }_c,{\bar{D}}_s{\Lambda }_c$ or ${\bar{D}}^{\ast }{\Xi }_c,{\bar{D}}_s^{\ast }{\Lambda }_c$ channels, with a strong transition potential, collaborate to produce a larger attraction than the corresponding states $\bar{D}{\Sigma }_c,\bar{D}{\Lambda }_c$ or ${\bar{D}}^{\ast }{\Sigma }_c,{\bar{D}}^{\ast }{\Lambda }_c$ appearing in the generation of the strangenessless $P_c$ states, since in the latter case the transition potential between those channels is zero. The extra attraction obtained in the $\bar{D}{\Xi }_c,{\bar{D}}^{\ast }{\Xi }_c$ pairs preclude the association of these channels to the $P_{cs}(4338)$ and $P_{cs}(4459)$ states respectively. Then we find a natural association of the $P_{cs}(4338)$ state coupling mostly to ${\bar{D}}^{\ast }{\Xi }_c$ while the $P_{cs}(4459)$ is associated to the state found that couples mostly to $\bar{D}{\Xi }_c^{\prime }$. Four more states appear, like in other molecular pictures, and some of the states are degenerate in spin. Counting different spin states we find $10$ states, which we hope can be observed in the near future.

    ↳ hep-phhep-exhep-latnucl-thPLB(2023)·56 citations
11. 11*

    Unexpected results of the phase transitions of four-state Potts model on the square and the honeycomb lattices

    Jhao-Hong Peng🇨🇳 · Fu-Jiun Jiang🇹🇼

    It is widely believed that the phase transition for the four-state ferromagnetic Potts model on the square lattice is of the pseudo-first order. Specifically, it is expected that first-order phase transition behavior is found on small lattices and that the true nature of second-order phase transition only emerges with large system sizes. It is also intuitively expected that for other geometries, the types of the associated phase transitions should be identical to that of the square lattice. However, after simulating more than 16 million spins for the four-state Pott model, we observe that a feature of first-order phase transition persists on the square lattice. Additionally, a characteristic of second-order phase transition already appears on a small honeycomb lattice. Indications of a pseudo-first-order phase transition were not found in our investigation. This suggests that a thorough analytic calculation may be required to develop a better understanding of the presented results.

    ↳ cond-mat.stat-mechhep-latPTEP(2024)·3 citations
12. 12*

    A lattice pairing-field approach to ultracold Fermi gases

    Florian Ehmann🇩🇪 · Joaquín E. Drut🇺🇸 · Jens Braun🇩🇪

    We develop a pairing-field formalism for ab initio studies of non-relativistic two-component fermions on a $(d+1)$-dimensional spacetime lattice. More specifically, we focus on theories where the interaction between the two components can be described by the exchange of a corresponding pairing field. The introduction of a pairing field may indeed be convenient for studies of, e.g., the finite-temperature phase structure and critical behavior of, e.g., ultracold atomic Fermi gases. Moreover, such a formalism allows to directly compute the momentum and frequency dependence of the pair propagator, from which the pair-correlation function can be extracted. For a first illustration of the application of our formalism, we compute the density equation of state and the superfluid order parameter for a gas of unpolarized fermions in $(0+1)$ dimensions by employing the complex Langevin approach to surmount the sign problem.

    ↳ cond-mat.quant-gashep-latSciPost Phys.(2024)·1 citation

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.