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Hyperon vector coupling f_1(0) from 2+1 flavor lattice QCD

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 نشر من قبل Shoichi Sasaki
 تاريخ النشر 2011
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 تأليف Shoichi Sasaki




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We present results for the hyperon vector form factor f_1 for $Xi^0 rightarrow Sigma^+ lbar{ u}$ and $Sigma^- rightarrow n lbar{ u}$ semileptonic decays from dynamical lattice QCD with domain-wall quarks. Simulations are performed on the 2+1 flavor gauge configurations generated by the RBC and UKQCD Collaborations with a lattice cutoff of 1/a = 1.7 GeV. Our preliminary results, which are calculated at the lightest sea quark mass (pion mass down to approximately 330 MeV), show that a sign of the second-order correction of SU(3) breaking on hyperon vector coupling f_1(0) is likely negative.



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We present the first result for the hyperon vector form factor f_1 for Xi^0 -> Sigma^+ l bar{nu} and Sigma^- -> n l bar{nu} semileptonic decays from fully dynamical lattice QCD. The calculations are carried out with gauge configurations generated by the RBC and UKQCD collaborations with (2+1)-flavors of dynamical domain-wall fermions and the Iwasaki gauge action at beta=2.13, corresponding to a cutoff 1/a=1.73 GeV. Our results, which are calculated at the lighter three sea quark masses (the lightest pion mass down to approximately 330 MeV), show that a sign of the second-order correction of SU(3) breaking on the hyperon vector coupling f_1(0) is negative. The tendency of the SU(3) breaking correction observed in this work disagrees with predictions of both the latest baryon chiral perturbation theory result and large N_c analysis.
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