<XML><RECORDS><RECORD><REFERENCE_TYPE>0</REFERENCE_TYPE><REFNUM>5967</REFNUM><AUTHORS><AUTHOR>Poet,D.A.</AUTHOR><AUTHOR>Poet,R.</AUTHOR></AUTHORS><YEAR>2000</YEAR><TITLE>Conic confocal billiards</TITLE><PLACE_PUBLISHED> </PLACE_PUBLISHED><PUBLISHER>Academic Press</PUBLISHER><PAGES>277-284</PAGES><ISBN>Physics Letters A</ISBN><LABEL>Poet:2000:5967</LABEL><KEYWORDS><KEYWORD>conic; billiards; integrabillity; caustics</KEYWORD></KEYWORDS<ABSTRACT>We examine the billiard problem for two new integrable boundaries: two confocal parabolae with anti-parallel axes, and a confocal ellipse and hyperbola. In each case an equation for the caustic and a second constant of motion are found geometrically. Non-focal orbits are found to produce caustics, while focal orbits are found to either asymptotically tend to the axis or form a closed orbit of period two or four. </ABSTRACT></RECORD></RECORDS></XML>