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Published on: June 28, 2018
Spin structure of the pion.
D Brömmel1, M Diehl, M Göckeler
1Deutsches Elektronen-Synchrotron DESY, 22603 Hamburg, Germany.
We calculated the pion's transverse spin structure using lattice quantum chromodynamics (QCD). Results show a quark distribution asymmetry, similar to nucleons, supporting the universality of Boer-Mulders functions.
Area of Science:
- * Quantum Chromodynamics (QCD) and Hadron Physics
- * Computational Physics and Lattice Gauge Theory
Background:
- * Understanding the transverse spin structure of hadrons is crucial for a complete picture of nucleon structure.
- * Previous calculations explored quark transverse spin asymmetries in the nucleon.
Purpose of the Study:
- * To perform the first lattice QCD calculation of the pion's transverse spin structure.
- * To investigate the spatial distribution of transversely polarized quarks within the pion.
- * To compare the pion's spin structure with that of the nucleon.
Main Methods:
- * Utilized lattice QCD simulations with two flavors of nonperturbatively improved Wilson fermions.
- * Employed pion masses as low as 400 MeV and volumes up to (2.1 fm)^3.
- * Used lattice spacings below 0.1 fm for high precision.
Main Results:
- * Observed a characteristic asymmetry in the spatial distribution of transversely polarized quarks in the pion.
- * The magnitude of this asymmetry is comparable to that found for quarks in the nucleon.
- * Demonstrated a similarity between the pion and nucleon transverse spin structures.
Conclusions:
- * The findings provide the first direct evidence for a specific transverse spin structure in the pion.
- * Results support the hypothesis that Boer-Mulders functions are universal across different hadrons.
- * This study advances the understanding of spin phenomena in quantum chromodynamics.
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