E.C. AschenauerEIC Detector R&D Committee Meeting, October 20121

Simulation Workshop  8 th & 9 th of October  Agenda Agenda Agenda  Covered Topics  Physics case for the EIC  Golden measurements to benchmark the detector performance  Software simulation tools (physics generators,fast smearing generator,..) physics generators not discussed here summarized perfectly in detector simulations ….) computing power and environment  eRHIC and ELIC/MEIC IR designs tracking of protons and neutrons through IR  machine backgrounds (hadronic, synchrotron radiation, …) E.C. Aschenauer EIC Detector R&D Committee Meeting, October

What needs to be covered E.C. AschenauerEIC Detector R&D Committee Meeting, October e’t (Q 2 ) e L*L*L*L* x+ξ x-ξ H, H, E, E (x,ξ,t) ~ ~  J  p p’ Inclusive Reactions in ep/eA:  Physics: Structure Fcts.: F 2, F L  Very good electron id  find scattered lepton  Momentum/energy and angular resolution of e’ critical  scattered lepton  kinematics Semi-inclusive Reactions in ep/eA:  Physics: TMDs, Helicity PDFs  flavor separation, dihadron-corr.,…  Kaon asymmetries, cross sections  Kaon asymmetries, cross sections  Excellent particle ID  ±,K ±,p ± separation over a wide range in   full  -coverage around  *  Excellent vertex resolution  Charm, Bottom identification Exclusive Reactions in ep/eA:  Physics: GPDs, proton/nucleus imaging, DVCS, excl. VM/PS prod.  Exclusivity  large rapidity coverage  rapidity gap events  ↘ reconstruction of all particles in event  high resolution in t  Roman pots

Inclusive DIS E.C. AschenauerEIC Detector R&D Committee Meeting, October Measure of resolution power Measure of inelasticity Measure of momentum fraction of struck quark e-p/A 0 o 180 o +  diverges for y e  0 depends on E’ e diverges for  ’ e  180 o depends on E’ e and  ’ e E’ e and  ’ e Note:  to measure x, y, and Q 2 at low Q 2 ~ 1 GeV 2  Electron method precise energy and angular resolution for  ’ e  180 o and high y  At low y use hadron method Hadron method:

DIS Kinematics E.C. AschenauerEIC Detector R&D Committee Meeting, October  Even for colliders: Strong x-Q 2 correlation  high x  high Q 2  low x  low Q 2 low y-coverage: limited by E’ e resolution  hadron method high y limited by radiative corrections can be suppressed by requiring hadronic activity HERAy>0.005 Possible limitations in kinematic coverage:

Lepton Kinematics E.C. AschenauerEIC Detector R&D Committee Meeting, October Increasing Lepton Beam Energy: 5 GeV: Q 2 ~ 1 GeV   ~ GeV: Q 2 ~ 1 GeV   ~ -4 highest E’ e at most negative rapidities independent of E h √s

Scattered Lepton Kinematics E.C. AschenauerEIC Detector R&D Committee Meeting, October CUTS: Q 2 >0.1GeV 2 && GeV 2 && 0.01<y<0.95 higher √s: scattered lepton has small scattering angle  negative rapidities

Pion Kinematics E.C. AschenauerEIC Detector R&D Committee Meeting, October Cuts: Q 2 >1 GeV, Increasing Hadron Beam Energy: influences max. hadron energy at fixed  Increasing 30 GeV < √s < 170 GeV  hadrons are boosted from forward rapidities to negative rapidities  the same for  , K ±, p ± √s

Hadron, lepton, Photon Separation E.C. AschenauerEIC Detector R&D Committee Meeting, October GeVx50 GeV hadronphotonelectron no cuts applied hadron/photon suppression factor needed for p e’ >1GeV: -3<  <-2: ~ <  <0: ~1000 p max hadron for PID: -5<  <-1: < 10 GeV -1<  <-1: < 5 GeV 1<  <5: < 50 GeV 1<  <5: < 50 GeV

Lepton Identification E.C. AschenauerEIC Detector R&D Committee Meeting, October GeVx250 GeV hadronphotonelectron no cuts applied hadron/photon suppression factor needed for p e’ >1GeV: <  <-2: ~ p max hadron for PID: -5<  <-1: < 30 GeV -1<  <-1: < 10 GeV 1<  <5: < 100 GeV 1<  <5: < 100 GeV

Fast Simulator: What was modeled  Magnetic field: Solenoid with 3.0 Tesla  Tracking:  “Central” +/-1: TPC-like: 45 fit points; 0.03 radiation length, position resolution: 80   “Forward” 1-3: GEM-like: 6 planes; 0.03 radiation length, position resolution: 80   “Far Forward” 3-4.5: Si-Pixel-like: 12 planes; 0.03 radiation length, position resolution: 20   radiation length needs to be checked  no bremsstrahlung for electrons yet  Ecal  “Central” +/-1: like submitted proposal 10%√E+1.5% hadron: MIP + 0.4E h with  =0.2E h (50:50)  “Forward” 1-5: like submitted proposal 10%√E+1.5% hadron: MIP with  =0.2E h (50:50)  “Backward” -1 to -5: PWO crystal calorimeter 2.5%/√E + 0.9% + 1%/E hadron: MIP + 0.4E h with  =0.2E h (50:50)  “Hcal:  Forward” 1-5: like current STAR forward R&D project: 38%√E+3% EIC Detector R&D Committee Meeting, October E.C. Aschenauer

Fast Simulator: Check  Used fast smearing simulator  multiple scattering and momentum smearing included according to PDG  check against STAR results at central region  looks okay  for details: EIC Detector R&D Committee Meeting, October <  <1 assumed 0.05 radiation lengths E.C. Aschenauer

Momentum resolutions E.C. AschenauerEIC Detector R&D Committee Meeting, October <  < <  < <  < <  <4.5 To improve momentum resolution for  >3 need to look in Magnet design with more radial field

E.C. AschenauerEIC Detector R&D Committee Meeting, October compare performance of tracking to F_L requirements as determined by Chiapas want plot to compare Calo. resolutions with tracking for different rapidity

Improve Momentum Resolution: Magnet Design E.C. AschenauerEIC Detector R&D Committee Meeting, October Discuss on one slide our results for the ILC-concept 4 magnet vs. normal Solenoid

Resolution for E/p E.C. AschenauerEIC Detector R&D Committee Meeting, October E e : 5 GeV Q 2 >1 GeV -1 1 GeV -1<  <-1 E e : 20 GeV Q 2 >1 GeV -1 1 GeV -1<  <-1 1<p<3 7<p<9 1<p<2 4<p<5

Resolution for E/p E.C. AschenauerEIC Detector R&D Committee Meeting, October E e : 5 GeV Q 2 >1 GeV GeV -2.2<  <-1 E e : 20 GeV Q 2 >1 GeV GeV -3.7<  <-1 1<p<3 7<p<9 1<p<2 4<p<5

LHC-b: possible RICH design concepts E.C. AschenauerEIC Detector R&D Committee Meeting, October RICH-1 (modern HERMES RICH) RICH-2 2<p<60 GeV 17<p<100 GeV mrad mrad 5cm Aerogel (n=1.030) ~200 cm CF 4 (n=1.0005) 85 cm C 4 F 10 (n=1.0014)

Cerenkov and momentum resolution EIC Detector R&D Committee Meeting, October  p/p<0.1%  p/p< 1.0%  p/p< 3.0% p E.C. Aschenauer  no resolution due to photon detector is yet modeled  momentum resolution absolutely critical for good , K, p separation

Exclusive Reactions: Event Selection E.C. AschenauerEIC Detector R&D Committee Meeting, October proton tag method o Measurement of t o Free of p-diss background o Higher M X range o to have high acceptance (roman Pots) challenging  IR design Pots) challenging  IR design Diffractive peak Large Rapidiy Gap method o X system and e’ measured o Proton dissociation background o High acceptance MYMYMYMY Q2Q2Q2Q2W How can we select events: two methods Need for roman pots spectrometer Need for Hcal in the forward region

Scattered proton acceptance E.C. AschenauerEIC Detector R&D Committee Meeting, October Maindetector RomanPots leading protons are never in the main detector acceptance at EIC (stage 1 and 2) eRHIC detector acceptance Cuts: Q 2 >1 GeV, GeV Increasing Hadron Beam Energy: influences max. photon energy at fixed  Increasing 30 GeV < √s < 170 GeV  photons are boosted from symmetric to negative rapidities to negative rapidities

5x100 GeV 20x250 GeV t-Measurement using RP E.C. AschenauerEIC Detector R&D Committee Meeting, October Accepted in“Roman Pot”(example) at s=20m Plots from J-H Lee Quadrupoles acceptance 10  from the beam-pipe high ‐ |t| acceptance mainly limited by magnet aperture high ‐ |t| acceptance mainly limited by magnet aperture low ‐ |t| acceptance limited by beam envelop (~10σ) low ‐ |t| acceptance limited by beam envelop (~10σ) |t| ‐ resolution limited by |t| ‐ resolution limited by – beam angular divergence ~100μrad for small |t| – uncertainties in vertex (x,y,z) and transport – ~<5-10% resolution in t (RP at STAR) Simulation based on eRHIC REQUIREMENTS Acceptance at large-|t|  proper design of quadrupole magnets Acceptance at large-|t|  proper design of quadrupole magnets Acceptance in the whole solid angle Acceptance in the whole solid angle High momentum resolution High momentum resolution radiation hardness radiation hardness

Photon-Lepton discrimination E.C. AschenauerEIC Detector R&D Committee Meeting, October e  N.B. - Need for a ECal with a granularity to distinguish clusters down to  =1 deg to distinguish clusters down to  =1 deg This is also important for  calculation in asymmetries measurement an for BH rejection in the xsec measurement

BH rejection E.C. AschenauerEIC Detector R&D Committee Meeting, October In DVCS most of the photon are less “rear” Than the electrons: (θ el -θ g ) > 0  rejects most of the BH BH and DVCS BH dominated

BH Rejection E.C. AschenauerEIC Detector R&D Committee Meeting, October Eel EγEel Eel Eel Eγ Eγ Eγ 1.BH electron has very low energy (often below 1 GeV) 2.Photon for BH (ISR) goes often forward (trough the beam pipe) Important: ECal must discriminate clusters above noise down to 1 GeV

Start full Geant Simulations E.C. AschenauerEIC Detector R&D Committee Meeting, October  Postdoc Alexander Kiselev started 3 rd of Dec  Framework: virtual MC using FairRoot

Cross section: Pythia  ep : – mb Luminosity: cm -1 s -1 = 10 7 mb -1 s -1 Some thought about rates E.C. AschenauerEIC Detector R&D Committee Meeting, October low multiplicity 4-6 √s = GeV N ch (ep) ~ N ch (eA) < N ch (pA)  no occupancy problem Interaction rate: kHz

Summary E.C. AschenauerEIC Detector R&D Committee Meeting, October

E.C. AschenauerEIC Detector R&D Committee Meeting, October BACKUP

E.C. AschenauerEIC Detector R&D Committee Meeting, October Executive Summary Physicists representing several of the current EIC R&D efforts met for two days at Brookhaven Lab. The purpose of the meeting was to consolidate simulation efforts to most efficiently formulate: 1) Physics-driven detector performance constraints. 2) Radiation dose estimates (including machine-specific backgrounds). 3) Coherent simulation strategies. Presentations included discussion on: * The physics scope of EIC. * Processes that drive detector performance. * Current software efforts. * Available computing resources. * Detailed machine designs. * Current machine-background estimates. In the concluding session, the participants formulated both their broad goals and a short-term To-Do list. BROAD GOALS: 1) Formulate Requirement Tables/Maps. Each requirement table/map stipulates the limiting values of a detector performance parameter (e.g. dp/p, material budget, PID purity) as functions of both polar angle and particle momentum. These tables/maps in principle can be made for each driving physics process. 2) Formulate a Dose Table/Map. Dose Tables/maps specify the radiation load on detector systems from various sources (collisions, backgrounds) as functions of detector location. 3) Build a Full Simulation. The full simulation should follow modern coding practices as a "virtual simulation framework" (e.g. FairRoot or GEMC) and incorporate both physics and background sources.

E.C. AschenauerEIC Detector R&D Committee Meeting, October ) Formulate Systematic Error Estimates. EIC will be systematics-limited, not statistics-limited. Experimental sources of systematic error (calibration, scale determination, final state radiation, machine background) should be evaluated relative to attainable theoretical uncertainties. Clearly this task requires the detailed full detector simulation for measurements of inclusive, exclusive, and SIDIS channels. SHORT TERM TO DO LIST: 1) Constraint Maps: Develop requirement maps for SIDIS & DVCS to complement those for inclusive cross sections. 2) Dose Maps: Starting with the physics dose map, add backgrounds from the electron beam (bremsstrahlung) and hadron beam (beam-gas). 3) Simulation Development: a- Implement a double-solenoid field map. b- Stipulate by and Phone Conference the radial budgets for detector subsystems. c- Assign initial coding options to people with appropriate interests.

lepton kinematics E.C. AschenauerEIC Detector R&D Committee Meeting, October

Simulation Example E.C. AschenauerEIC Detector R&D Committee Meeting, October Cuts: Q 2 >1 GeV,

Integration into Machine: IR-Design E.C. AschenauerEIC Detector R&D Committee Meeting, October space for low-  e-tagger Outgoing electron direction currently under detailed design  detect low Q 2 scattered leptons  want to use the vertical bend to separate very low-  e’ from beam-electrons  can make bend faster for outgoing beam  faster separation  for 0.1 o <  <1 o will add calorimetry after the main detector

Emerging Detector Concept 35 Backward Spectrometer For very low Q 2 -electrons: Magnet 2-3T space for low-  e-tagger E.C. Aschenauer high acceptance -5 <  < 5 central detector good PID ( ,K,p and lepton) and vertex resolution (< 5  m) tracking and calorimeter coverage the same  good momentum resolution, lepton PID Barrel: MAPS & TPC, Forward: MAPS & GEM low material density  minimal multiple scattering and brems-strahlung very forward electron and proton/neutron detection  Roman Pots, ZDC, low e-tagger EIC Detector R&D Committee Meeting, October 2012

Kinematics of Breakup Neutrons E.C. AschenauerEIC Detector R&D Committee Meeting, October Results from GEMINI++ for 50 GeV Au by Thomas Ullrich +/-5mrad acceptance seems sufficient Results: With an aperture of ±3 mrad we are in relative good shape enough “detection” power for t > GeV 2 enough “detection” power for t > GeV 2 below t ~ 0.02 GeV 2 we have to look into photon detection below t ~ 0.02 GeV 2 we have to look into photon detection ‣ Is it needed? Question: For some physics rejection power for incoherent is needed ~10 4 For some physics rejection power for incoherent is needed ~10 4  How efficient can the ZDCs be made?

Diffractive Physics: p’ kinematics 5x250 5x100 5x50 E.C. Aschenauer 37 EIC Detector R&D Committee Meeting, October 2012 t=(p 4 -p 2 ) 2 = 2[(m p in.m p out )-(E in E out - p z in p z out )]  “ Roman Pots” acceptance studies see later ? Diffraction: p’ Simulations by J.H Lee

proton distribution in y vs x at s=20 m 20x2505x50 E.C. Aschenauer 38 EIC Detector R&D Committee Meeting, October 2012 without quadrupole aperture limit 20x250 5x50 with quadrupole aperture limit

Accepted in“Roman Pot”(example) at s=20m 20x2505x50 E.C. Aschenauer 39 EIC Detector R&D Committee Meeting, October x2505x50 Generated Quad aperture limited RP (at 20m) accepted Summary:  Still a lot of work to be done  But we have started to address all the important issues integration of detector and forward particle reconstruction into integration of detector and forward particle reconstruction into machine design Synchrotron radiation Synchrotron radiation………

Exclusive Vector Meson Production 40  Golden channel: e + A → e’ + A’ + VM ‣ Only channel where t can be derived from VM and e’ ‣ Detecting neutron emission from nuclear breakup allows to separate coherent from incoherent Dipole Cross-Section: J/   E.C. AschenauerEIC Detector R&D Committee Meeting, October 2012

Detection efficiency of Breakup Neutrons E.C. AschenauerEIC Detector R&D Committee Meeting, October Results: With an aperture of ±3 mrad we are in relative good shape even for 50 GeV Au beams enough “detection” power for t > GeV 2 enough “detection” power for t > GeV 2 below t ~ 0.02 GeV 2 we have to look into photon detection below t ~ 0.02 GeV 2 we have to look into photon detection ‣ Is it needed? Assumptions: Gemini++ is correct, was verified by SMM Gemini++ is correct, was verified by SMM E* ~ -t/2mN E* ~ -t/2mN Can we make a ZDC 100% (> %) efficient Can we make a ZDC 100% (> %) efficient ‣ do we understand neutron detection on the level?