Tue·Oct 18, 2022Tuesday·October 18, 2022

1. 01*

   Prospects for ${\gamma }^{\star }{\gamma }^{\star }\to \pi \pi$ via lattice QCD

   Raúl A. Briceño🇺🇸 · Andrew W. Jackura🇺🇸 · Arkaitz Rodas🇺🇸 · Juan V. Guerrero🇺🇸

   The ${\gamma }^{\star }{\gamma }^{\star }\to \pi \pi$ scattering amplitude plays a key role in a wide range of phenomena, including understanding the inner structure of scalar resonances as well as constraining the hadronic contributions to the anomalous magnetic moment of the muon. In this work, we explain how the infinite-volume Minkowski amplitude can be constrained from finite-volume Euclidean correlation functions. The relationship between the finite-volume Euclidean correlation functions and the desired amplitude holds up to energies where $3\pi$ states can go on shell, and is exact up to exponentially small corrections that scale like $\mathcal{O}(e^{-m_{\pi }L})$, where $L$ is the spatial extent of the cubic volume and $m_{\pi }$ is the pion mass. In order to implement this formalism and remove all power-law finite volume errors, it is necessary to first obtain $\pi \pi \to \pi \pi$, $\pi {\gamma }^{\star }\to \pi$, ${\gamma }^{\star }\to \pi \pi$, and $\pi \pi {\gamma }^{\star }\to \pi \pi$ amplitudes; all of which can be determined via lattice quantum chromodynamic calculations.

   hep-lathep-phnucl-thPRD(2023)·8 citations
2. 02*

   Spectroscopy of $Sp(4)$ lattice gauge theory with $n_f=3$ antisymmetric fermions

   Jong-Wan Lee🇰🇷 · Ed Bennett🇬🇧 · Deog Ki Hong🇰🇷 · Ho Hsiao🇹🇼 · C.-J. David Lin🇹🇼 · Biagio Lucini🇬🇧 · Maurizio Piai🇬🇧 · Davide Vadacchino🇬🇧

   We perform numerical calculations of masses and decay constants of the lightest (flavoured) pseudoscalar, vector and axial vector mesons in the $Sp(4)$ lattice gauge theory with three Dirac fermions in the antisymmetric representation. The corresponding continuum theory plays an important role in certain ultra-violet complete realisations of composite Higgs, partial top compositeness, and composite dark matter models. In addition, we measure the masses of other flavoured mesons in spin-$0$ and $1$ channels, as well as the first excited state of the vector mesons. Using the gradient flow to set the scale, we carry out the continuum extrapolation and show preliminary results for the meson spectrum of the theory.

   hep-lathep-phPoS(2023)·13 citations
3. 03*

   First observation of the hidden-charm pentaquarks on lattice

   Hanyang Xing🇨🇳 · Jian Liang🇨🇳 · Liuming Liu🇨🇳 · Peng Sun🇨🇳 · Yi-Bo Yang🇨🇳

   The s-wave scattering of ${\Sigma }_c\bar{D}$ and ${\Sigma }_c{\bar{D}}^{\ast }$ in the $I(J^P)=\frac{1}{2}({\frac{1}{2}}^{-})$ channel is calculated in lattice QCD using two ensembles with different volumes but the same lattice spacing $a\sim 0.08\mathrm{fm}$ and pion mass $M_{\pi }\sim 294\mathrm{MeV}$. The scattering amplitudes near threshold are obtained by Lüscher's finite volume method. We find bound state poles in both ${\Sigma }_c\bar{D}$ and ${\Sigma }_c{\bar{D}}^{\ast }$ channels, which are possibly related to the $P_c(4312)$ and $P_c(4440)/P_c(4457)$ pentaquarks observed in experiments. The binding energy is $6(2)(2)$MeV for ${\Sigma }_c\bar{D}$ and $7(3)(1)$MeV for ${\Sigma }_c{\bar{D}}^{\ast }$, where the first error is the statistical error and the second is the systematic error due to the lattice artifacts.

   hep-lathep-exhep-ph32 citations
4. 04*

   Grassmann tensor-network method for strong-coupling QCD

   Jacques Bloch🇩🇪 · Robert Lohmayer🇩🇪

   We present a tensor-network method for strong-coupling QCD with staggered quarks at nonzero chemical potential. After integrating out the gauge fields at infinite coupling, the partition function can be written as a full contraction of a tensor network consisting of coupled local numeric and Grassmann tensors. To evaluate the partition function and to compute observables, we develop a Grassmann higher-order tensor renormalization group method, specifically tailored for this model. We apply the method to the two-dimensional case and validate it by comparing results for the partition function, the chiral condensate and the baryon density with exact analytical expressions on small lattices up to volumes of $4\times 4$. For larger two-dimensional volumes, we present tensor results for the chiral condensate as a function of the mass and volume, and observe that the chiral symmetry is not broken dynamically in two dimensions. Furthermore, our results for the number density as a function of the chemical potential hint at a first-order phase transition. Finally, we present some preliminary tensor results for three-dimensional strong-coupling QCD.

   hep-latPoS(2023)·3 citations
5. 05*

   Lattice QCD study of antiheavy-antiheavy-light-light tetraquarks based on correlation functions with scattering interpolating operators both at the source and at the sink

   Marc Wagner🇩🇪 · Constantia Alexandrou🇨🇾 · Jacob Finkenrath🇨🇾 · Theodoros Leontiou🇨🇾 · Stefan Meinel🇺🇸 · Martin Pflaumer🇩🇪

   We present first results of a recently started lattice QCD investigation of antiheavy-antiheavy-light-light tetraquark systems including scattering interpolating operators in correlation functions both at the source and at the sink. In particular, we discuss the importance of such scattering interpolating operators for a precise computation of the low-lying energy levels. We focus on the $\bar{b}\bar{b}ud$ four-quark system with quantum numbers $I(J^P)=0(1^{+})$, which has a ground state below the lowest meson-meson threshold. We carry out a scattering analysis using Lüscher's method to extrapolate the binding energy of the corresponding QCD-stable tetraquark to infinite spatial volume. Our calculation uses clover $u$, $d$ valence quarks and NRQCD $b$ valence quarks on gauge-link ensembles with HISQ sea quarks that were generated by the MILC collaboration.

   hep-lathep-phPoS(2023)·11 citations

* 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.