Les Houches

ttbar: mismodeling of top pt and spin correlations. There are tensions between ATLAS and CMS in top distributions. Other variables to look at? Dedicated study performed by MC authors, comprehensive of main uncertainties.

W-mass and precise EW measurements: where are the bottlenecks? Is the specific ATLAS W-mass tune working well for all observables (y_Z)?

Vector Bosons scattering: follow up from LH17. Continue “benchmarking” study at NLO, to expose differences due to different approximations made in the NLO computation. NLO+PS: check distributions and make sure all EXP are aware of differences among different generators and showers.

EW effects in PS. It's known that they are important for HE. Collect/study examples where these effects are relevant, produce some representative plots. LH proceeding can become a reference, as well as a place where the “TH challenge” is stated.

High performance computing: can we use LH as a platform to initiate some study on performances, negative weights, etc. What are the needs for high-energy pp machines and more in general to future colliders? How should we define a metric?

Legacy data: what’s the best format, how to make sure TH can easily access it, and even just find the important information for their needs (e.g. for PDF fitters and constraints on EFT). Is HEPDATA enough? Can we use it more efficiently?

Z+1 jet: distorsion of Z rapidity / PS mapping for radiation.