SQL Server GRANT EXECUTE ON TRIGGER TO USER

I have this trigger:

我有这个触发器:

CREATE TRIGGER [dbo].[TRIGGER_UPDATE_MODIFIED]
   ON  [dbo].[MY_TABLE]   
   AFTER UPDATE 
AS 
BEGIN

    SET NOCOUNT ON;    

    UPDATE [dbo].[MY_TABLE] SET [DATE_MODIFIED] = GETDATE(), [USER_MODIFIED] = CASE WHEN UPDATE ([USER_MODIFIED]) THEN i.[USER_MODIFIED] ELSE RIGHT(SUSER_NAME(), 100) END
    FROM INSERTED i
    WHERE [MY_TABLE].[SOME_FIELD] = i.[SOME_FIELD]

END
CREATE TRIGGE