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Nucleon isovector charges from physical mass domain-wall QCD

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 نشر من قبل Shigemi Ohta
 تاريخ النشر 2019
  مجال البحث
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 تأليف Shigemi Ohta KEK




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Systematics in nucleon isovector vector, $g_V$, and axialvector, $g_A$, charges calculated on a 2+1-flavor dynamical domain-wall-fermions (DWF) ensemble at physical mass jointly generated by RIKEN-BNL-Columbia (RBC) and UKQCD Collaborations with lattice cut off of 1.730(4) GeV, are analyzed. Both are calculated with about a percent or less statistical errors. A few standard-deviation systematics seen in vector charge is consistent with possible $O(a^2)$ discretization error through small excited-state contamination. Axialvector charge is found with three to nine standard-deviation systematic deficit, compared with experiments, depending on calculation methods.



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Nucleon isovector vector, $g_V$, and axialvector, $g_A$, charges calculated on a 2+1-flavor dynamical domain-wall-fermions (DWF) ensemble at physical mass jointly generated by RIKEN-BNL-Columbia (RBC) and UKQCD Collaborations with lattice cut off of 1.730(4) GeV, are reported with about a percent statistical errors, along with isovector ``scalar, $g_S$, and ``tensor charges, $g_T$, with larger statistical errors. Nucleon mass is estimated as 947(6) MeV. A few standard-deviation systematics is seen in the vector charge, likely from $O(a^2)$ discretization error through small excited-state contamination. The axialvector charge is found with a few to several standard-deviation systematic deficit, depending on calculation methods, in comparison with the experiment. Nucleon signal is likely lost as early as 10 lattice units or about 1.1 fm in time from the source.
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