<qa>  What is the final dose to be used in the Panel 2?This is a two-part Phase 1 study consisting of a dose escalation part Panel 1 and a thorough QT TQT part Panel 2. Panel 1 will be a double-blind neither the researchers nor the participants know what treatment the participant is receiving, randomized study medication assigned to participants by chance, placebo-controlled dose escalation study in healthy participants to determine the safety, tolerability and pharmacokinetics of JNJ-63623872 after administration of single doses of 2400 milligrams mg and 3000 mg under fasted conditions. The final dose to be used in the Panel 2 will be determined based on the results of this dose escalation part. An interim analysis will be conducted on Panel 1 to select the dose for Panel 2. Panel 2 will be a double-blind, double-dummy, randomized, 3-period crossover the same medications provided to all participants but in different sequence, placebo- and positive controlled study to evaluate the effect of JNJ-63623872 on the QTQTc interval in healthy participants. Participants safety will be monitored throughout the study. 