Preprint

PUBDB-2026-02867

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Subtraction method for disconnected diagrams in full QCD

Barca, L. (Corresponding author)DESY* ; Crawford, J. ; Finkenrath, J. -. F. ; Schaefer, S.DESY* ; Urrea Niño, J. A.Extern*

2026

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Please use a persistent id in citations: doi:10.3204/PUBDB-2026-02867

Report No.: DESY-26-127; WUB/26-04; arXiv:2609.37049

Abstract: Disconnected diagrams remain a major challenge for precision lattice QCD calculations because of their large statistical fluctuations. We investigate a subtraction method basedon a domain decomposition of the Dirac operator, yielding a biased but substantially less noisy estimator. Applying the method to charmonium disconnected correlators computedusing distillation, we achieve a variance reduction of about three orders of magnitude at only twice the computational cost, providing a practical alternative to completely neglecting disconnected contributions.

Note: 16 pages, 7 figures

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Contributing Institute(s):

1. Zeuthen Particle PhysicsTheory (Z_ZPPT)

Research Program(s):

1. 611 - Fundamental Particles and Forces (POF4-611) (POF4-611)
2. DFG project G:(GEPRIS)451886959 - FOR 5269 Zukünftige Methoden für Studien von eingeschlossenen Gluonen in QCD (451886959) (451886959)
3. DFG project G:(GEPRIS)440719683 - Hochleistungscompute-Cluster (440719683) (440719683)

Experiment(s):

1. No specific instrument

Appears in the scientific report 2026

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