Calculation of $ K→πlν$ form factor in $N_f = 2+1$ QCD at physical point on $(10 \text{fm})^3$

Kakazu, Junpei; Ishikawa, Ken-Ichi; Ishizuka, Naruhito; Kuramashi, Yoshinobu; Nakamura, Yoshifumi; Namekawa, Yusuke; Taniguchi, Yusuke; Ukita, Naoya; Yamazaki, Takeshi; Yoshie, Tomoteru; on behalf of PACS Collaboration,

doi:10.22323/1.334.0265

Abstract

We present our preliminary result of the form factor of

$K→πlν$ semileptonic decays on the large volume configuration,

$L\approx10$ fm, with the physical

$m_\pi$ and

$m_K$ using the stout-smearing clover quark and Iwasaki gauge actions at

$a^{−1}=2.333$ GeV. From an interpolation using the data in small momentum transfers, we determine the semileptonic decay form factors at zero momentum transfer. The result is compared with the previous lattice calculations. We also estimate the value of

$|V_{us}|$ by combining our result with the experimental value of the kaon semileptonic decay.