Search for Proton Decay via $p \rightarrow \nu K^{+}$ using 260 kiloton$\cdot$year data of Super-Kamiokande

We have searched for proton decay via $p \rightarrow \nu K^{+}$ using Super-Kamiokande data from April 1996 to February 2013, 260 kiloton$\cdot$year exposure in total. No evidence for this proton decay mode is found. A lower limit of the proton lifetime is set to $5.9 \times 10^{33}$ years at 90% confidence level.