Update on complementarity from the Far Forward and IR WG group

• Alexander Jentsch (Brookhaven National Lab)
• Yulia Furletova (Jefferson Lab)

Questions to start discussion: - What is your current baseline thinking? - How might a second detector differ in technology choices and what (dis)advantages might that bring in terms of kinematic coverage, resolution on reconstructed variables, radiation hardness, dominating systematics etc? - Are there wider implications for other parts of the detector - eg due to material budgets? - Would the complementary designs naturally be associated with different choices of solenoid field, centre of mass energy, luminosity or beam polarisation? - Are there any limitations in the performance of your sub detector technologies for very small bunch spacing < 9ns - Are there any rate limitations? - Is +/- 4.5 m enough longitudinal space to fit the detector - Are there any issues we should be aware of in terms of cost, technology readiness, or time required to construct the detector? - Might it be possible to combine more than one function into your detector(s)? - Do your detector technologies have any impact on the design of the interaction region? - What studies need to be done (or have been done already) to make fully quantitative statements?