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So we just need another tune to fit the data, don’t we?

So we just need another tune to fit the data, don’t we?. Zoltan Nagy. So we just need another tune to fit the data, don’t we?. Zoltan Nagy. MPI kernel : NLO → Need to consider NLO and colour-subleading contributions to standard shower.

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So we just need another tune to fit the data, don’t we?

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  1. So we just need another tune to fit the data, don’t we? Zoltan Nagy Anna Kulesza (RWTH Aachen) Summary of soft QCD WG part 2

  2. So we just need another tune to fit the data, don’t we? Zoltan Nagy MPI kernel : NLO → Need to consider NLO and colour-subleading contributions to standard shower Anna Kulesza (RWTH Aachen) Summary of soft QCD WG part 2

  3. So we just need another tune to fit the data, don’t we? Zoltan Nagy MPI kernel : NLO → Need to consider NLO and colour-subleading contributions to standard shower Anna Kulesza (RWTH Aachen) Summary of soft QCD WG part 2

  4. So we just need another tune to fit the data, don’t we? Zoltan Nagy Colour reconnection effects are important when comparing MC predictions to data Anna Kulesza (RWTH Aachen) Summary of soft QCD WG part 2

  5. So we just need another tune to fit the data, don’t we? Zoltan Nagy Colour reconnection effects are important when comparing MC predictions to data Anna Kulesza (RWTH Aachen) Summary of soft QCD WG part 2

  6. Do we have a good understanding of MPIs and mPDFs? Jo Gaunt Battlefield restricted to Double Parton Scattering Assumption: “dPDF framework”, used in phenomenology → longitudinal-transverse factorization also in MCs Anna Kulesza (RWTH Aachen) Summary of soft QCD WG part 2

  7. Do we have a good understanding of MPIs and mPDFs? Jo Gaunt Evolution equations for dPDFs known, would give contributions to DPS cross sections of the sort: • According to dPDF the diagram should contribute a DGLAP log but well known box diagram contributions, e.g. for gg→ZZ,are finite! Anna Kulesza (RWTH Aachen) Summary of soft QCD WG part 2

  8. Do we have a good understanding of MPIs and mPDFs? Jo Gaunt Evolution equations for dPDFs known, would give contributions to DPS cross sections of the sort: • According to dPDF the diagram should contribute a DGLAP log but well known box diagram contributions, e.g. for gg→ZZ,are finite! • In general, all diagrams with the “DPS-singularity” give only integrable contributions to the cross section: this is a correction to a single scattering process • The apparent inconsistency due to the transverse-longitudinal factorization assumption: the dPDF framework breaks down! Anna Kulesza (RWTH Aachen) Summary of soft QCD WG part 2

  9. Do we have a good understanding of MPIs and mPDFs? Evolution equations for dPDFs known Jo Gaunt • Impact on phenomenology – definition of DPS cross section? • DPS at high pT will be measured: another test of MPI models in MCs • mPDFs and mPDFs running in MC? • Interference effects in flavour, spin and colour? • According to dPDF the diagram should contribute a DGLAP log but the well known box diagram contributions are finite! • In general, all diagrams with the “DPS-singularity” give only integrable contributions to the cross section: this is a correction to a single scattering process • The apparent inconsistency due to the transverse-longitudinal factorization assumption: the dPDF framework breaks down! Anna Kulesza (RWTH Aachen) Summary of soft QCD WG part 2

  10. What is the impact of soft QCD corrections on jet physics? MrinalDasgupta Anna Kulesza (RWTH Aachen) Summary of soft QCD WG part 2

  11. What is the impact of soft QCD corrections on jet physics? MrinalDasgupta Hadronization <δpt>h~ -1/R Underlying Event <δpt>UE~ R2 • Soft QCD corrections to jets Anna Kulesza (RWTH Aachen) Summary of soft QCD WG part 2

  12. MrinalDasgupta An example of measurement particularly sensitive to UE modelling? But beware, difficult measurement! (track jets?) Anna Kulesza (RWTH Aachen) Summary of soft QCD WG part 2

  13. What would be the impact of soft QCD effects on(feasibility of some) LHC searches? Jet-pull method: identification of hard subprocess from studying colour flow Simone Marzani Expect: Anna Kulesza (RWTH Aachen) Summary of soft QCD WG part 2

  14. What would be the impact of soft QCD effects on (feasibility of some) LHC searches? Jet-pull method: identification of hard subprocess from studying colour flow Simone Marzani Expect: But get: b Anna Kulesza (RWTH Aachen) Summary of soft QCD WG part 2

  15. The DIPSY alternative Gösta Gustafson DIPSY = Dipole Event Generator Anna Kulesza (RWTH Aachen) Summary of soft QCD WG part 2

  16. The DIPSY alternative Gösta Gustafson • The DIPSY alternative Fair description of exclusive final states: MB and UE Anna Kulesza (RWTH Aachen) Summary of soft QCD WG part 2

  17. Gösta Gustafson Anna Kulesza (RWTH Aachen) Summary of soft QCD WG part 2

  18. Gösta Gustafson from DIPSY Anna Kulesza (RWTH Aachen) Summary of soft QCD WG part 2

  19. Summary of the soft QCD working group Within this working group: • Proposed: new measurements • Emphasized: need to compare data with various availableMC models* / identify measurements which cannot be well described by all MCs/tunes • Highlighted: many theoretical issues / open questions in the description of soft QCD • The real big question: Are we happy with the current status? Is tuning the end of the story? Certainly not satisfactory from the theory point of view… *i.e. Sherpa Anna Kulesza (RWTH Aachen) Summary of soft QCD WG part 2

  20. Summary of the soft QCD working group cntd. Open call to both theory and experiment: Is there a need for more measurements? Can we come up with measurements sensitive to particular aspects of soft QCD (hadronization, MPI, non-perturbative)? Proposals need to be made now! Anna Kulesza (RWTH Aachen) Summary of soft QCD WG part 2

  21. Summary of the soft QCD working group Open call to both theory and experiment: Is there a need for more measurements? Can we come up with measurements sensitive to particular aspects of soft QCD (hadronization, MPI, non-perturbative)? Proposals need to be made now! Many thanks to all the speakers and contributors! Anna Kulesza (RWTH Aachen) Summary of soft QCD WG part 2

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