Measurements of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"><mml:mi mathvariant="normal">t</mml:mi><mml:mover accent="true"><mml:mrow><mml:mi mathvariant="normal">t</mml:mi></mml:mrow><mml:mrow><mml:mo stretchy="false">¯</mml:mo></mml:mrow></mml:mover></mml:math> cross sections in association with b jets and inclusive jets and their ratio using dilepton final states in pp collisions at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.gif" overflow="scroll"><mml:msqrt><mml:mrow><mml:mi>s</mml:mi></mml:mrow></mml:msqrt><mml:mo>=</mml:mo><mml:mn>13</mml:mn><mml:mspace width="0.2em"/><mml:mtext>TeV</mml:mtext></mml:math>

The cross sections for the production of t tb b and t tjj events and their ratio ttb b/ ttjj are measured using data corresponding to an integrated luminosity of 2.3 fb -1 collected in pp collisions at s = 13 TeV with the CMS detector at the LHC. Events with two leptons (e or ) and at least four reconstructed jets, including at least two identified as b quark jets, in the final state are selected. In the full phase space, the measured ratio is 0.022 0.003 (stat) 0.006 (syst), the cross section ttb b is 4.0 0.6 (stat) 1.3 (syst) pb and ttjj is 184 6 (stat) 33 (syst) pb. The measurements are compared with the standard model expectations obtained from a powheg simulation at next-to-leading-order interfaced with pythia.