on ▁neut r ino ▁beam , ▁while ▁negative ▁p ions ▁and ▁ka ons ▁decay ▁mainly ▁into ▁ ▁and ▁, ▁forming ▁a ▁mu on ▁ant ine ut r ino ▁beam . ▁All ▁remaining ▁had rons ▁and ▁charged ▁le pt ons ▁are ▁stopped ▁by ▁a ▁ 7 5 - ton ▁block ▁of ▁graph ite ▁( so - called ▁beam ▁dump ) ▁and ▁in ▁the ▁ground , ▁while ▁neut r inos ▁travel ▁under ground ▁towards ▁the ▁far ▁det ector . ▁ ▁Off - axis ▁beam ▁ ▁T 2 K ▁is ▁the ▁first ▁experiment ▁in ▁which ▁the ▁concept ▁of ▁off - axis ▁neut r ino ▁beam ▁was ▁realized . ▁The ▁neut r ino ▁beam ▁at ▁J - PAR C ▁is ▁designed ▁so ▁that ▁it ▁can ▁be ▁directed ▁ 2 ▁to ▁ 3 ▁degrees ▁away ▁from ▁the ▁Super - K ami ok ande ▁far ▁det ector ▁and ▁one ▁of ▁the ▁near ▁detect ors , ▁N D 2 8 0 . ▁The ▁off - axis ▁angle ▁was ▁chosen ▁to ▁ 2 . 5 ° ▁to ▁maxim ize ▁the ▁probability ▁of ▁oscill ation ▁at ▁a ▁distance ▁corresponding ▁to ▁the ▁far ▁det ector , ▁which ▁for ▁ 2 9 5   km ▁is ▁maximal ▁for ▁around ▁ 6 0 0   Me V ▁neut r inos . ▁In ▁this ▁neut r ino ▁energy ▁range , ▁the ▁dominant ▁type ▁of ▁neut r ino ▁interactions ▁are ▁charged ▁current ▁qu as iel astic ▁interactions , ▁for ▁which ▁it ▁is ▁possible ▁to ▁re construct ▁the ▁energy ▁of ▁the ▁interact ing ▁neut r ino ▁only ▁on