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FCCeePhysicsPerformance

Welcome to the FCC-ee Physics Performance Documentation

Table of Contents

  1. Latest Integrated Luminosity Table for Feasibility Study Report
  2. Organisation
  3. Towards the definition of detector requirements
  4. List of Active Case studies (evolving)
  5. General information for FCC-ee analyses
  6. LOIs submitted to Snowmass
  7. Software

Integrated Luminosity Table for Feasibility Study Report

——— More details here below: The FCC-ee baseline is now with four interaction points. The latest instantaneous luminosities were given by Oide San in San Francisco last June. See slide 3 of https://indico.cern.ch/event/1298458/contributions/5977859/attachments/2873388/5034194/Optics_Oide_240611.pdf:

At the Z: 143 10^34 cm-2 s-1 at each IP at the WW threshold: 20 10^34 at the ZH maximum: 7.5 10^34 at 365 GeV: 1.38 10^34 (not indicated in this slide: at the ttbar threshold: 1.72 10^34)

We will run 4 years at the Z (with the first two years at half lumi for commissioning) 2 years at the WW threshold 3 years at the ZH maximum 1 year at the ttbar threshold (at half lumi) 4 years at 365 GeV

Giving

At and around the Z pole: 205 ab-1 (~40 ab-1 at 88 GeV, ~40 ab-1 at 94 GeV, ~125 ab-1 at the Z pole - about 6 . 10^12 Z in total)

At the WW threshold: 19.2 ab-1 (typically half at 157.5 GeV and half at 162.5 GeV, maybe also another energy point to measure the continuum background below 157.5 GeV, in which case the luminosity would be divided in three thirds. This optimisation needs to be done.)

At the ZH maximum: 10.8 ab-1 (~2 million ZH events)

At the ttbar threshold: 0.41 ab-1 (~2 million ttbar events altogether) At 365 GeV: 2.65 ab-1

[The ttbar points can also be distributed differently: only 0.2 ab-1 for the threshold scan if it is enough, and 2.81 ab-1 at 365 GeV. This is fine structure.] ———–

Organisation

Coordinators

Physics Performance meetings

O(monthly) meetings: Mondays, 3pm-5pm, CERN time. Usually the third Monday of each month.

E-group used for announcements: FCC-PED-FeasibilityStudy. To subscribe, go here.

Towards the definition of detector requirements

Goal: Circular colliders have the advantage of delivering collisions to multiple interaction points, which allow different detector designs to be studied and optimized – up to four for FCC-ee. On the one hand, the detectors must satisfy the constraints imposed by the invasive interaction region layout. On the other hand, the performance of heavy-flavour tagging, of particle identification, of tracking and particle-flow reconstruction, and of lepton, jet, missing energy and angular resolution, need to match the physics programme and the exquisite statistical precision offered by FCC-ee. Benchmark physics processes will be used to determine, via appropriate simulations, the requirements on the detector performance or design that must be satisfied to ensure that the systematic uncertainties of the measurements are commensurate with their statistical precision. The usage of the data themselves, in order to reach the challenging goals on the stability and on the alignment of the detector, in particular for the programme at and around the Z peak, will also be studied. In addition, the potential for discovering very weakly coupled new particles, in decays of Z or Higgs bosons, could motivate dedicated detector designs that would increase the efficiency for reconstructing the unusual signatures of such processes. These studies are crucial input to the further optimization of the two concepts described in the Conceptual Design Report, CLD and IDEA, and to the development of new concepts which might actually prove to be better adapted to (part of) the FCC-ee physics programme.

Case studies (evolving list)

  1. Electroweak physics at the Z peak
  2. Tau Physics
  3. Flavour physics
  4. WW threshold
  5. QCD measurements
  6. Higgs physics
  7. Top physics
  8. Direct searches for new physics

General information for FCC-ee analyses

  1. Common event samples
  2. Example analyses and how-to’s
    1. Basics
    2. How to associate RecoParticles with Monte-Carlo Particles
    3. How to navigate through the history of the Monte-Carlo particles
    4. How to compute event variables (thrust, sphericity, etc)
    5. How to fit tracks to a common vertex
    6. How to run jet algorithms
    7. How to run kinematic fits
  3. Code development
  4. To produce your own Delphes samples
    1. Quick instructions for producing samples
    2. Make simple changes to the tracker or beam-pipe description in Delphes
    3. Change the Jet algorithms
  5. The five-parameter tracks produced by the Delphes interface
  6. Vertexing and flavour tagging
    1. Vertex-fitter code from Franco Bedeschi
    2. Vertexing with the ACTS suite
    3. The LCFI+ algorithm
    4. The DecayTreeFitter (DTF) algorithm
    5. Flavour tagging using machine learning
  7. Making particle combinations with awkward arrays
  8. Generating events under realistic FCC-ee environment conditions
    1. Beam energy spread
    2. Vertex distribution
    3. Transverse boost to account for the crossing angle
  9. Monte-Carlo programs
  10. Bibliography

LOIs submitted to Snowmass

Software Documentation & Links

Software tutorials

Useful repositories