%0 Journal Article %T Search for the proton decay mode $p \rightarrow \overline¦Í K^{+}$ with KamLAND %A KamLAND Collaboration %J Physics %D 2015 %I arXiv %R 10.1103/PhysRevD.92.052006 %X We present a search for the proton decay mode $p \rightarrow \overline{\nu} K^{+}$ based on an exposure of 8.97 kton-years in the KamLAND experiment. The liquid scintillator detector is sensitive to successive signals from $p \rightarrow \overline{\nu} K^{+}$ with unique kinematics, which allow us to achieve a detection efficiency of 44%, higher than previous searches in water Cherenkov detectors. We find no evidence of proton decays for this mode. The expected background, which is dominated by atmospheric neutrinos, is $0.9 \pm 0.2$ events. The nonbackground-subtracted limit on the partial proton lifetime is $\tau / B(p \rightarrow \overline{\nu} K^{+}) > 5.4 \times 10^{32}$ years at 90% C.L. %U http://arxiv.org/abs/1505.03612v3