HEP Lattice·hep-lat

Fri·Nov 19, 2021Friday·November 19, 2021

9 papers—5 primary·4 cross-listed·reconstructed*

01*
Phases at finite winding number of an Abelian lattice gauge theory
Paolo Stornati🇪🇸 · Debasish Banerjee🇮🇳 · Karl Jansen🇩🇪 · Philipp Krah🇩🇪
Pure gauge theories are rather different from theories with pure scalar and fermionic matter, especially in terms of the nature of excitations. For example, in scalar and fermionic theories, one can create ultra-local excitations. For a gauge theory, such excitations need to be closed loops that do not violate gauge invariance. In this proceedings, we present a study on the condensation phenomenon associated with the string-like excitations of an Abelian lattice gauge theory. These phenomena are studied through numerical simulations of a $U (1)$ quantum link model in 2+1 dimensions in a ladder geometry using matrix product states. In this proceedings, we show the existence of ground states characterized by the presence of such string-like excitations. These are caused due to the condensation of torelons. We also study the relationship between the properties of the plaquettes in the ground state and the presence of such condensation phenomenon.
hep-latcond-mat.str-elquant-phPoS(2022)·1 citation
02*
Density of states approach for lattice field theory with topological terms
Christof Gattringer🇦🇹 · Oliver Orasch🇦🇹
We discuss a new density of states (DoS) approach to solve the complex action problem that is caused by topological terms. The key ingredient is to use open boundary conditions for (at least) one of the directions, such that the quantization of the topological charge is lifted and the density becomes a regular function. We employ the DoS FFA method and compute the density of states as a function of the topological charge. Subsequent integration with suitable factors gives rise to the observables we are interested in. We here explore two test cases: U(1) lattice gauge theory in two dimensions, and SU(2) lattice gauge theory in four dimensions. Since the 2-d case has an exact solution we may use it to assess the method, in particular to establish the equivalence of the open boundary results with the usual choice of periodic boundary conditions. The SU(2) case is a first step of developing the techniques towards their eventual application in full QCD.
hep-latPoS(2022)·4 citations
03*
Continuum limit of baryon-baryon scattering with SU(3) flavor symmetry
Jeremy R. Green🇨🇭 · Andrew D. Hanlon🇺🇸 · Parikshit M. Junnarkar🇩🇪 · Hartmut Wittig🇩🇪
We report a study of the scattering of two octet baryons using lattice QCD. The baryon-baryon spectrum is computed using distillation on eight lattice ensembles spanning six lattice spacings and multiple volumes, all at the SU(3) flavor symmetric point with $m_{π} = m_{K} \approx 420$ MeV. Using finite-volume quantization conditions, we determine the scattering phase shift and the presence of bound states. Focusing on the $H$ dibaryon, our results show large discretization effects: in the continuum, the binding energy is $B_{H} = 4.56 \pm 1.13 \pm 0.63$ MeV, whereas on our coarsest lattice spacing this is larger by a factor of about 7.5. We also present preliminary results for a $D$ -wave phase shift and for the spectrum in the nucleon-nucleon $^{1} S_{0}$ channel.
hep-latPoS(2022)·13 citations
04*
Imprint of chiral symmetry restoration on the Polyakov loop and the heavy quark free energy
David Anthony Clarke🇩🇪 · Olaf Kaczmarek🇩🇪 · Frithjof Karsch🇩🇪 · Anirban Lahiri🇩🇪 · Mugdha Sarkar🇩🇪
The Polyakov loop expectation value $⟨ P ⟩$ is an order parameter of the deconfinement transition in the heavy quark mass regime, whereas its sensitivity to the deconfinement of light, dynamical quarks is not apparent. From the perspective of an effective Lagrangian in the vicinity of the chiral transition, the Polyakov loop, $P$ , is an energy-like observable, and $⟨ P ⟩$ should hence scale like the energy density. Using $N_{f} = 2 + 1$ HISQ configurations at finite lattice spacing, we show that near the chiral transition temperature, the scaling behavior of $⟨ P ⟩$ and the heavy quark free energy $F_{q}$ is consistent with energy-like observables in the 3- $d$ , O( $N$ ) universality class. We extend this analysis to other Polyakov loop observables, including the response of the heavy quark free energy, $F_{q}$ , to the baryon chemical potential, which is expected to scale like a specific heat.
hep-lathep-phPoS(2022)·1 citation
05*
FLAG Review 2021
Y. Aoki🇯🇵 · T. Blum🇺🇸 · G. Colangelo🇨🇭 · S. Collins🇩🇪 · M. Della Morte🇩🇰 · P. Dimopoulos🇮🇹 · S. Dürr🇩🇪 · X. Feng🇨🇳 · H. Fukaya🇯🇵 · M. Golterman🇺🇸 · Steven Gottlieb🇺🇸 · R. Gupta🇺🇸 and 25 other authors
We review lattice results related to pion, kaon, $D$ -meson, $B$ -meson, and nucleon physics with the aim of making them easily accessible to the nuclear and particle physics communities. More specifically, we report on the determination of the light-quark masses, the form factor $f_{+} (0)$ arising in the semileptonic $K \to π$ transition at zero momentum transfer, as well as the decay constant ratio $f_{K} / f_{π}$ and its consequences for the CKM matrix elements $V_{u s}$ and $V_{u d}$ . Furthermore, we describe the results obtained on the lattice for some of the low-energy constants of $S U (2)_{L} \times S U (2)_{R}$ and $S U (3)_{L} \times S U (3)_{R}$ Chiral Perturbation Theory. We review the determination of the $B_{K}$ parameter of neutral kaon mixing as well as the additional four $B$ parameters that arise in theories of physics beyond the Standard Model. For the heavy-quark sector, we provide results for $m_{c}$ and $m_{b}$ as well as those for the decay constants, form factors, and mixing parameters of charmed and bottom mesons and baryons. These are the heavy-quark quantities most relevant for the determination of CKM matrix elements and the global CKM unitarity-triangle fit. We review the status of lattice determinations of the strong coupling constant $α_{s}$ . We consider nucleon matrix elements, and review the determinations of the axial, scalar and tensor bilinears, both isovector and flavor diagonal. Finally, in this review we have added a new section reviewing determinations of scale-setting quantities.
hep-lathep-phEPJC(2022)·967 citations
06*
Exploring smoking-gun signals of the Schwinger mechanism in QCD
A. C. Aguilar🇧🇷 · M. N. Ferreira🇧🇷 · J. Papavassiliou🇪🇸
In QCD, the Schwinger mechanism endows the gluons with an effective mass through the dynamical formation of massless bound-state poles that are longitudinally coupled. The presence of these poles affects profoundly the infrared properties of the interaction vertices, inducing crucial modifications to their fundamental Ward identities. Within this general framework, we present a detailed derivation of the non-Abelian Ward identity obeyed by the pole-free part of the three-gluon vertex in the soft-gluon limit, and determine the smoking-gun displacement that the onset of the Schwinger mechanism produces to the standard result. Quite importantly, the quantity that describes this distinctive feature coincides formally with the bound-state wave function that controls the massless pole formation. Consequently, this signal may be computed in two independent ways: by solving an approximate version of the pertinent Bethe-Salpeter integral equation, or by appropriately combining the elements that enter in the aforementioned Ward identity. For the implementation of both methods we employ two- and three-point correlation functions obtained from recent lattice simulations, and a partial derivative of the ghost-gluon kernel, which is computed from the corresponding Schwinger-Dyson equation. Our analysis reveals an excellent coincidence between the results obtained through either method, providing a highly nontrivial self-consistency check for the entire approach. When compared to the null hypothesis, where the Schwinger mechanism is assumed to be inactive, the statistical significance of the resulting signal is estimated to be three standard deviations.
↳ hep-phhep-lathep-thPRD(2022)·47 citations
07*
Update on strong and radiative decays of the $D_{s 0}^{*} (2317)$ and $D_{s 1} (2460)$ and their bottom cousins
Hai-Long Fu🇨🇳 · Harald W. Grießhammer🇺🇸 · Feng-Kun Guo🇨🇳 · Christoph Hanhart🇩🇪 · Ulf-G. Meißner🇩🇪
The isospin breaking and radiative decay widths of the positive-parity charm-strange mesons, $D_{s 0}^{*}$ and $D_{s 1}$ , and their predicted bottom-strange counterparts, $B_{s 0}^{*}$ and $B_{s 1}$ , as hadronic molecules are revisited. This is necessary, since the $B_{s 0}^{*}$ and $B_{s 1}$ masses used in Eur. Phys. J. A 50 (2014) 149 were too small, in conflict with the heavy quark flavour symmetry. Furthermore, not all isospin breaking contributions were considered. We here present a method to restore heavy quark flavour symmetry, correcting the masses of $B_{s 0}^{*}$ and $B_{s 1}$ , and include the complete isospin breaking contributions up to next-to-leading order. With this we provide updated hadronic decay widths for all of $D_{s 0}^{*}$ , $D_{s 1}$ , $B_{s 0}^{*}$ and $B_{s 1}$ . Results for the partial widths of the radiative deays of $D_{s 0}^{*} (2317)$ and $D_{s 1} (2460)$ are also renewed in light of the much more precisely measured $D^{*+}$ width. We find that $B_{s} π^{0}$ and $B_{s} γ$ are the preferred channels for searching for $B_{s 0}^{*}$ and $B_{s 1}$ , respectively.
↳ hep-phhep-exhep-latEPJA(2022)·44 citations
08*
The strangest lifetime: A bizarre story of $τ (Ω_{c}^{0})$
Hai-Yang Cheng🇹🇼
For a long time it has been established both experimentally and theoretically that $Ω_{c}^{0}$ is shortest-lived among the four singly charmed baryons which decay weakly. The situation was dramatically changed in 2018 when LHCb reported a new measurement of the $Ω_{c}^{0}$ lifetime using semileptonic $b$ -hadron decays. The value is nearly four times larger than the previous world average of $τ (Ω_{c}^{0})$ and it is confirmed by the most recent LHCb measurement with the prompt production. In this viewpoint article, we review the status and point out that heavy quark expansion (HQE) fails to apply to $Ω_{c}^{0}$ to the order of $1/ m_{c}^{4}$ . By demanding a sensible HQE for $Ω_{c}^{0}$ will lead to a lifetime of $Ω_{c}^{0}$ longer than $Λ_{c}^{+}$ .
↳ hep-phhep-exhep-latSci. Bull. \textbf{67}, 445-447 (2022)·18 citations
09*
Doubly heavy baryons in Born-Oppenheimer EFT
Jaume Tarrús Castellà🇺🇸
We report on the recent progress on the computation of the doubly heavy baryon spectrum in effective field theory. The effective field theory is built upon the heavy-quark mass and adiabatic expansions. The potentials can be expressed as NRQCD Wilson loops with operator insertions. These are nonperturbative objects and so far only the one corresponding to the static potential has been computed with lattice QCD. We review the proposal for a parametrization of the potentials based in an interpolation between the short- and long-distance regimes. The long-distance description is obtained with a newly proposed Effective String Theory which coincides with the previous ones for pure gluodynamics but it is extended to contain a fermion field. We show the doubly heavy baryon spectrum with hyperfine contributions obtained using these parametrizations for the hyperfine potentials.
↳ hep-phhep-exhep-latEPJ Web Conf.(2022)·5 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.