You can see which SQL Server Extended Event sessions are running using the following code

SqlServerExtendedEventSessions.sql

SELECT
	[ses].[name] AS [Session Name],
	CASE
		WHEN [xs].[address] IS NOT NULL THEN 'Running'
		ELSE 'Stopped'
	END AS [State],
	[xs].[create_time] AS [Start Time]
FROM sys.server_event_sessions AS [ses]
left outer JOIN sys.dm_xe_sessions AS [xs]
	ON [ses].[name] = [xs].[name]
ORDER BY [State], [Start Time];