EIC SOFTWARE TOOLS AND NEEDS Franco Bradamante, A. B., Anna Martin, Giulio Sbrizzai

Starting model detector layout -4<h<4: Tracking & e/m Calorimetry (hermetic coverage) hadronic calorimeters e/m calorimeters RICH detectors SBS CBM EIC R&D (UCLA, BNL) EIC R&D (UCLA, BNL) ALICE silicon trackers TPC GEM trackers 3T solenoid coils 7/23/2019 A. Bressan

Wish list for EIC Reach in kinematic variables Reliable electron identification Good hadron PID High spatial resolution of primary vertex Low material budget The more close to 4p acceptance the better Luminosity and polarization measurement Close-to-beam-line acceptance add-on detectors to register recoil protons low Q2 electrons neutrons in hadron beam direction And all this at affordable price! 7/23/2019 A. Bressan

COMPUTING TOOLS The software runs on the RACF @ BNL (RHIC and ATLAS Computing Facility) where the EIC group has its own nodes, where I do have an account. 7/23/2019 A. Bressan

EIC Root based on FairRoot Slide from Florian Uhlig (ROOT 2015 Workshop) 7/23/2019 A. Bressan

EicRoot framework building blocks Interface to GEANT, ROOT, … FairBase PandaRoot FopiRoot Track finder, TPC R&D stuff, … Presently we are focused on this part EicRoot CbmRoot GENERATOS (eic-smear) RICH stuff solenoid modeling IR design configuration 7/23/2019 A. Bressan

IR v2.1: implementation in EicRoot photon transport line with Al exit window Roman Pots +18 m electrons +4.5 m 0 m -4.5 m dipole magnet for pair spectrometer -15 m low Q2 tagger -31 m Legend: beam pipe hadron magnet apertures electron magnet apertures emcals for lumi monitor -33m -45 m 7/23/2019 A. Bressan

Our experience from COMPASS Generators (from good-old Lepto to Pythia 6…BTW EIC plans to bring ℓ𝑁 in Pythia 8) RC tools Radgen Djangoh/HERACLES GEANT Moreover we plan to use the comparison with the COMPASS data to validate the new tools developed. i.e. relevant synergies with COMPASS that remains our primary activity 7/23/2019 A. Bressan

Present Activities for EIC Insert spin effects into the Monte Carlo event generators (presently focused on FFs): Account for radiative effects at Monte Carlo level Run EIC ROOT to give inputs for hardware design RICH dedicated simulations 7/23/2019 A. Bressan

Radiative Corrections (DJANGOH/HERACLES) 𝑄 2 =− ℓ− ℓ ′ −𝑘 2 𝑥 = 𝑄 2 2𝑃∙ ℓ− ℓ ′ −𝑘 Photon radiation from the leptons modify the one boson cross-section and change the DIS kinematics on the event by event basis The direction of the virtual photon is different from the one reconstructed from the leptons, giving rise to: False asymmetries in the azimuthal distribution of hadrons calculated with respect to the virtual photon direction Smearing of the kinematic distributions (e.g. 𝑧 and 𝑃 ℎ𝑇 ) To take into account correctly this effect in the SIDIS cross-section we need both the correct weights for every event and an unfolding procedure for the smearing. THIS can ONLY be done by using a Monte Carlo code for RC

Radiative Corrections : Deliverables Deliverables achieved at the end of the project: Calculate radiative corrections for transverse polarized observables to measure TMDs and polarized exclusive observables. Provide proof that the MC phase space constrains on the hadronic final state is equal to calculating radiative corrections for each polarized and unpolarized semi-inclusive hadronic final state independently. Define a software framework and develop a library based on this framework, which integrates the radiative corrections depending on polarization and other determining factors in a wrapper-software.

Synergies in RD_FA Study of Universality and Scaling: SIDIS: JLAB (6 and 12 GeV 𝑒 − ), HERMES (27 GeV 𝑒 − /completed), COMPASS (160 GeV 𝜇)….EIC (20-140 GeV cms). 𝑒 + 𝑒 − : BesIII (4 GeV cms), Babar (10 GeV cms), Belle e BelleII (10 GeV cms) 𝑝𝑝: RHIC (100-500 GeV cms) all involved in the study of transverse spin and momentum effects (what about LHC? Only After?) Test the portability simulation codes based on different FF models such as the cluster model of HERWIG ⟶ℓ𝑁 Comparison of tuning for Pythia/Jetset Development of common simulation codes? 7/23/2019 A. Bressan

Backup 7/23/2019 A. Bressan

EIC Root based on FairRoot Active project, officially supported by GSI Large experiment and user base Regular releases, active forums, long-term developer support Several software building blocks readily available Designed with flexibility in mind Simulation and reconstruction in the same environment ROOT-based I/O Virtual geometry concept (several formats supported) Virtual Monte-Carlo concept (easy switching between GEANT 3 & 4 transport engines in particular) 7/23/2019 A. Bressan

Geometry description Input formats: Output format: ROOT TGeo (required for tracking detectors) GEANT GDML Old HADES .geo files CAD design drawings (.stp, .stl, .slp) Output format: ROOT TGeo 7/23/2019 A. Bressan

Example: basic vertex+barrel tracker Vertex tracker + TPC in 3T field; 10 GeV/c pions at q=75o; momentum resolution? -> see examples/tracking/config.2 directory for details 7/23/2019 A. Bressan

Tracking: momentum resolution p+ p+; h=3 High resolution up to (at least) |h|~3 High redundancy (Reasonably) low cost Low material budget (see next slides) EIC R&D (Temple, Saclay) Variations: MuMegas barrels, smaller TPC radius, … 7/23/2019 A. Bressan

Tracking: smearing in kinematic variables {PYTHIA 20x250 GeV, NO bremsstrahlung} -> {GEANT} -> {Kalman filter track fit} same procedure; simulation WITH bremsstrahlung -> looks good despite poor resolution at low Y and long bremsstrahlung tails 7/23/2019 A. Bressan

Tracking: “purity” in (x,Q2) kinematic bins Describes migration between kinematic bins Important to keep it close to 1.0 for successful unfolding bremsstrahlung OFF bremsstrahlung ON Bremsstrahlung matters even for detector with ~5% X/X 0 “Straightforward” tracking can hardly help at Y<0.1 Other options: Tracking: try gaussian sum filter; account for kinks; etc … … or use e/m calorimeter? 7/23/2019 A. Bressan

Lepton Kinematics and (x,Q2) coverage Increasing lepton beam energy: scattered lepton is boosted to negative h Q2 > 1.0 GeV2: rapidity coverage -4 < h < 1 is sufficient Q2 < 0.1 GeV2: a dedicated low-Q2 tagger is required high y-coverage limited by radiative corrections -> can be suppressed by requiring hadronic activity low y-coverage limited by E’e resolution -> use hadron or double angle method to reconstruct event kinematics 7/23/2019 A. Bressan

SIDIS: Pion Kinematics Cuts: Q2>1 GeV2, 0.01<y<0.95, z>0.1 Increasing lepton beam energy boosts hadrons more to negative rapidity Increasing hadron beam energy influences max. hadron energy at fixed h (and p±, K±, p± look the same) -3<h<3 covers entire pt & z region important for physics 7/23/2019 A. Bressan

Interaction Region design 7/23/2019 A. Bressan

IR v2.1: design schematics Electron Direction (Rear Side) Hadron Direction (Forward Side) Cryostat Cryostat Forward Detectors Cryostat Synrad Fan Cryostat Central Detector Region Cryostat Cryostat Warm Quad IP Warm Quad 10 mrad Crossing Angle Zero Degree Neutral Detector (ZDC) Crab Cavity Apertures Cold Magnet Apertures space & ~1mrad acceptance for Lumi Monitor space & ~20mrad acceptance for low Q2 tagger space & ~8mrad acceptance for ZDC space & ~10mrad acceptance for Roman Pots 7/23/2019 A. Bressan

IR v2.1: implementation in EicRoot Hadron beam line Roman Pots location FFAG bypass Main detector Ecal tracking layers 20 cm 30cm Electron beam line Low Q2 tagger location -> field maps and magnet aperture sizes imported automatically -> Roman Pots, Low Q2 tagger & Lumi Monitor partly implemented 7/23/2019 A. Bressan

Low Q2 tagger {PYTHIA, 20x250 GeV} Compact detector system comprising of: 2 tracking layers -> reconstruct q EmCal -> reconstruct energy electrons Tuning phase: Check magnet bore locations & apertures Make sure magnetic field maps are correct Adjust scattering angle reconstruction code … Y-coordinate, [cm] X-coordinate, [cm] 7/23/2019 A. Bressan