High Energy Physics - Lattice
New submissions
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New submissions for Fri, 26 Apr 24
- [1] arXiv:2404.16191 [pdf, other]
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Title: Position-space renormalization schemes for four-quark operators in HQETComments: 25 pages, 3 figuresSubjects: High Energy Physics - Lattice (hep-lat); High Energy Physics - Phenomenology (hep-ph)
X-space schemes are gauge-invariant, regulator-independent renormalization schemes that are defined by requiring position-space correlation functions of gauge invariant operators to be equal to their noninteracting values at particular kinematic points. These schemes can be used to nonperturbatively renormalize composite operators in Lattice Quantum Chromodynamics (LQCD), and by computing matching coefficients between the X-space scheme and MSbar in the dimensionally-regulated continuum, matrix elements calculated with LQCD can be converted to MSbar-renormalized matrix elements. Using X-space schemes for Heavy Quark Effective Theory (HQET) operators has the additional benefit that appropriate ratios of position-space correlation functions cancel the power divergent static-quark self-energy of Lattice HQET nonperturbatively. This work presents the O($\alpha_S$) matching coefficients between X-space renormalized four-quark flavor-nonsinglet HQET operators relevant for the lifetimes of charm- and bottom-hadrons, and four-quark HQET operators relevant for mixing between neutral mesons containing a heavy quark, such as B-Bbar mixing.
- [2] arXiv:2404.16372 [pdf, ps, other]
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Title: Conserved currents in five-dimensional proposals for lattice chiral gauge theoriesComments: RevTex, 15 pagesSubjects: High Energy Physics - Lattice (hep-lat); High Energy Physics - Theory (hep-th)
We apply the Grabowska-Kaplan framework, originally proposed for lattice chiral gauge theories, to QCD. We show that the resulting theory contains a conserved and gauge invariant singlet axial current, both on the lattice and in the continuum limit. This must give rise to a difference with QCD, with the simplest possibility being a superfluous Nambu-Goldstone boson in the physical spectrum not present in QCD. We find a similar unwanted conserved current in the recent "disk" formalism [Kaplan, Kaplan & Sen], this time limiting ourselves to the continuum formulation. A similar problem is expected when either of these formalisms is used for its original goal of constructing lattice chiral gauge theories. Finally we discuss a conjecture about the possible dynamics that might be associated with the unwanted conserved current, and the fate of 't Hooft vertices.
- [3] arXiv:2404.16589 [pdf, other]
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Title: Preconditioned flow as a solution to the hierarchical growth problem in the generalized Lefschetz thimble methodComments: 35 pages, 5 figuresSubjects: High Energy Physics - Lattice (hep-lat); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics - Theory (hep-th); Computational Physics (physics.comp-ph); Quantum Physics (quant-ph)
The generalized Lefschetz thimble method is a promising approach that attempts to solve the sign problem in Monte Carlo methods by deforming the integration contour using the flow equation. Here we point out a general problem that occurs due to the property of the flow equation, which extends a region on the original contour exponentially to a region on the deformed contour. Since the growth rate for each eigenmode is governed by the singular values of the Hessian of the action, a huge hierarchy in the singular value spectrum, which typically appears for large systems, leads to various technical problems in numerical simulations. We solve this hierarchical growth problem by preconditioning the flow so that the growth rate becomes identical for every eigenmode. As an example, we show that the preconditioned flow enables us to investigate the real-time quantum evolution of an anharmonic oscillator with the system size that can hardly be achieved by using the original flow.
- [4] arXiv:2404.16702 [pdf, other]
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Title: Generalized boost transformations in finite volumes and application to Hamiltonian methodsComments: 30 pages, 5 figuresSubjects: High Energy Physics - Lattice (hep-lat); High Energy Physics - Phenomenology (hep-ph)
The investigation of hadron interactions within lattice QCD has been facilitated by the well-known quantisation condition, linking scattering phase shifts to finite-volume energies. Additionally, the ability to utilise systems at finite total boosts has been pivotal in smoothly charting the energy-dependent behaviour of these phase shifts. The existing implementations of the quantization condition at finite boosts rely on momentum transformations between rest and moving frames, defined directly in terms of the energy eigenvalues. This energy dependence is unsuitable in the formulation of a Hamiltonian.In this work, we introduce a novel approach to generalise the three-momentum boost prescription, enabling the incorporation of energy-independent finite-volume Hamiltonians within moving frames. We demonstrate the application of our method through numerical comparisons, employing a phenomenological $\pi\pi$ scattering example.
Cross-lists for Fri, 26 Apr 24
- [5] arXiv:2404.16454 (cross-list from quant-ph) [pdf, other]
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Title: Stabilizing quantum simulations of lattice gauge theories by dissipationComments: 7 pages, 7 figuresSubjects: Quantum Physics (quant-ph); High Energy Physics - Lattice (hep-lat)
Simulations of lattice gauge theories on noisy quantum hardware inherently suffer from violations of the gauge symmetry due to coherent and incoherent errors of the underlying physical system that implements the simulation. These gauge violations cause the simulations to become unphysical requiring the result of the simulation to be discarded. We investigate an active correction scheme that relies on detecting gauge violations locally and subsequently correcting them by dissipatively driving the system back into the physical gauge sector. We show that the correction scheme not only ensures the protection of the gauge symmetry, but it also leads to a longer validity of the simulation results even within the gauge-invariant sector. Finally, we discuss further applications of the scheme such as preparation of the many-body ground state of the simulated system.
- [6] arXiv:2404.16575 (cross-list from hep-ph) [pdf, other]
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Title: Probing the pole origin of $X(3872)$ with the coupled-channel dynamicsComments: 11 pages, 5 figuresSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Experiment (hep-ex); High Energy Physics - Lattice (hep-lat)
The $X(3872)$, as the first and the most crucial member in the exotic charmoniumlike $XYZ$ family, has been studied for a long time. However, its dynamical origin, whether stemming from a $D\bar{D}^*$ hadronic molecule or the first excited $P$-wave charmonium $\chi_{c1}(2P)$, remains controversial. In this Letter, we demonstrate that the $X(3872)$ definitely does not result from the mass shift of the higher bare $\chi_{c1}(2P)$ resonance pole in the coupled-channel dynamics involving a short-distance $c\bar{c}$ core and the long-distance $D\bar{D}^*$ channels. Instead, it originates from either the $D\bar{D}^*$ molecular pole or the shadow pole associated with the $P$-wave charmonium, which depends on the concrete coupling mode between the $c\bar{c}$ and $D\bar{D}^*$. In order to further exploit the nature of $X(3872)$, we carefully investigate potential mechanisms that contribute to its pole width, which suggests that the coupled-channel dynamics plays a critical role in causing a noticeable discrepancy between the pole widths of $X(3872)$ and $T_{cc}^+$. Interestingly, we bridge the quantitative connection among the dynamics origin of $X(3872)$, its pole width and the properties of the predicted new resonance. The precise measurement of the pole width of $X(3872)$ and the search for the new charmoniumlike resonance become highly significant and can be anticipated in future LHCb, BESIII and Belle II experiments.
Replacements for Fri, 26 Apr 24
- [7] arXiv:2312.12831 (replaced) [pdf, other]
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Title: First-Order Phase Transition of the Schwinger Model with a Quantum ComputerAuthors: Takis Angelides, Pranay Naredi, Arianna Crippa, Karl Jansen, Stefan Kühn, Ivano Tavernelli, Derek S. WangComments: 21 pages, 10 figures, 1 tableSubjects: High Energy Physics - Lattice (hep-lat); Quantum Physics (quant-ph)
- [8] arXiv:2401.12304 (replaced) [pdf, other]
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Title: New Physics couplings from angular coefficient functions of $\bar B \to D^* (D π) \ell \bar ν_\ell$Comments: RevTex, 8 pages, 6 figures. Added clarifications and references. Matches the published versionSubjects: High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Experiment (hep-ex); High Energy Physics - Lattice (hep-lat)
- [9] arXiv:2402.13983 (replaced) [pdf, other]
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Title: QCD parameters and SM-high precision from $e^+e^-$ to Hadrons: UpdatedAuthors: Stephan Narison (LUPM CNRS/IN2P3, Univ. Montpellier, and iHEPMAD, Univ. Antananarivo - MG)Comments: Latex sources, 19 pages, 8 figures, 3 tables. Some preliminaries results have been presented at the alphas2024 workshop (5-9th february 2024-ECT*-Trento-IT). Section 9 on the determination of alpha_s from tau-decay has been corrected. Version published in Nucl. Phys. A + Corrigendum (to appear in Nucl. Phys. A)Subjects: High Energy Physics - Phenomenology (hep-ph); High Energy Physics - Experiment (hep-ex); High Energy Physics - Lattice (hep-lat)
- [10] arXiv:2404.10269 (replaced) [pdf, other]
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Title: Status and progress of lattice QCDAuthors: Takashi KanekoComments: Presented at the 12th Workshop on the CKM Unitarity Triangle, 18-22 September 2023, Santiago de Compostela; v2: references addedSubjects: High Energy Physics - Lattice (hep-lat); High Energy Physics - Phenomenology (hep-ph)
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