Leonardo Rossi INFN Genova - UTOPIA #12 0 What we have learned from UTOPIA so far? Defined a set of gauge histos to compare layouts Exercised on barrel-part only and proved 4 Pixel layers better than 3 verified good reconstruction efficiency (barrel only) up to 400 pile-up requiring >10 clusters compared Pixel and Strips based on cost& power & X 0 cost and power and X 0 of short strips not much higher than long strips  extend their use to larger radius cost and power and X 0 of Pixel allows to use them up to a radius of ~25cm (if justified by simulation/physics) radiation damage and lifetime must consider part at r<10cm as removable cooling the cooler the better (<-25C on sensor) extension to end-cap coverage only started

Leonardo Rossi INFN Genova - UTOPIA # B-layer short (200  m) Pixel is a good move, but slightly harmful in barrel for  >1.5  must consider short b-layer(s) B-layer is critical for impact-parameter physics  must consider double b-layer to have a fall back in case of inefficiencies. Track trigger true L1 trigger impossible for HW and bandwidth limitations lot of effort went into the implementation of a layout which was Easy to modify Including a detailed description of services (also easy to scale with layout changes) in the mainstream of the ATLAS Athena simulation. With full rapidity coverage We have still few questions to address to close out, but real data have arrived and priorities have changed. What we have learned... This tool, together with the above results, will be the legacy of UTOPIA

Issues to conclude the UTOPIA mandate The comparison between alternative solutions should be based primarily on track efficiency, fake rate, impact parameter resolution (along r-phi and z), momentum resolution (all parameters vs eta, pt, particle type, pile-up, within jets). B-tagging can be considered later if time allows. Issues to be addressed to conclude the UTOPIA task force mandate: 1)Do we have a better layout with a 5 th Pixel layer?  compare 5P+4S layout with 4P+5S (both on barrel and end-cap) 2)Should we have the same number of hits in barrel and end-cap?  compare performance in barrel and in end-cap (including service material) 3)Do we have a better layout with all short strip detectors?  compare standard layout and all-short-strip layout (emphasis on jets and high pile-up) 4)Rapidity gap width around eta=1 vs momentum resolution  compare performance if 11 (or 10) hits are required in barrel, transition and end-cap. 5)Is full coverage a must?  compare performance with gaps (along z) between modules and no gap. Evaluate implication of absence of overlap for the alignment procedure. 6)How critical is the module tilt angle (Lorentz angle compensation)? Important for engineering simplification  compare same layout with 0, 10 and 15 degrees tilt 7)Robustness 1  compare 98%, 95% and 90% efficiency in a given layout 8)Robustness 2  compare layout w/nominal Rad. and Int. length per layer (X 0,  ), with same having 0.8(X 0,  ) and 1.5(X 0,  ). 9)Optimization of Pixel layout at high eta (long cluster problem)  compare high-eta impact parameter resolution with same at eta~0. 10)Impact of fast track trigger on layout  material and bandwidth needs (plus impact on reconstruction strategy in case of doublets of “close layers”). Leonardo Rossi INFN Genova - UTOPIA # impact of lumi levelling (simpler layout?)

To still afford the remaining issues we need: to find the right manpower able to commit The manpower situation for UTOPIA may only become worse in the near future as we are already the follower in the LHC competition either we do the work over the next month or we can forget it for a while this the focal point of the discussion... or just write a report with what we got so far and leave to some future body our legacy? Leonardo Rossi INFN Genova - UTOPIA #12 3 To discuss We have been dealing with a (fast) moving target and we have to wrap-up in any case here. This effort will be resumed when the sLHC plan will be known better.