MEIC Simulation and Reconstruction Group Report Tanja Horn 1 Tanja Horn, CUA Colloquium Tanja Horn, MEIC Simulation Group Report, EIC Detector Workshop 2010

Gluon and sea quark (transverse) imaging of the nucleon Nucleon Spin (  G vs. ln(Q 2 ), transverse momentum) Nuclei in QCD (gluons in nuclei, quark/gluon energy loss) QCD Vacuum and Hadron Structure and Creation Electroweak Physics Science Summary Energiessluminosity to 11 x Few x Future optionUp to 11 x Tanja Horn, MEIC Simulation Group Report, EIC Detector Workshop

Simulation Work Tanja Horn, MEIC Simulation Group Report, EIC Detector Workshop 2010 Nucleon spin – F L (x, Q 2 ) – g 1 (x, Q 2 ), Δ G/G, g p 1 -g n 1 –Gluon/quark transverse imaging (exclusive diffractive channels) Flavor Decomposition and transverse structure – Quark polarization Δ q(x): Δ u/u, Δ d/d, Δ s/s, Δ u/u, Δ d/d, Δ s/s, Δ u- Δ d – Transverse sea quark imaging (exclusive non-diffractive channels) – Transverse parton momenta (Mulders, Sivers, Transversity) Nuclear Medium – F L A (x, Q 2 ) – p T 2 3

Activities of the Simulation Working Group Tanja Horn, MEIC Simulation Group Report, EIC Detector Workshop 2010 Event Generators (standardized format) – Rate predictions including simulations of the detector restrictions – Input for detector design o Momentum and angular distributions for various particles Fast MC – Input: resolution function GEANT MC – Based on the CLAS12 simulation package GEMC Event Reconstruction/Tracking (for GEANT data) 4

Exclusive Processes: EIC Simulations Diffractive Channels – Data experience from HERA, COMPASS o γp(DVCS), ρ °p, φp, J/Ψp – DVCS simulations [A. Sandacz 06/07] Non-diffractive Channels – New territory for a collider! – Much more demanding in luminosity – Feasibility studies: π + n, π ° p, K + Λ 5 Tanja Horn, MEIC Simulation Group Report, EIC Detector Workshop 2010

J/ Ψ rate estimate uses a model based on a photoproduction parameterization –Branching ratio of 0.06 into e + e - (or μ + μ - ) has been included in rate estimates Models and rate estimates: J/Ψ and DVCS [Sandacz, Hyde, Weiss ’06/07+] Gluon size directly probed by J/ Ψ and φ production (Q 2 >10 GeV 2 ) –Require full t-distribution Fourier –Powerlike at |t|>1GeV 2 ? Do singlet quarks and gluons have the same transverse distribution? Gluon size from J/ Ψ, singlet quark size from DVCS Tanja Horn, MEIC Simulation Group Report, EIC Detector Workshop

Exclusive Generators: π + /K + e p π + ne p K + Λ [T. Horn with summer student: D. Cooper ’08] Tanja Horn, MEIC Simulation Group Report, EIC Detector Workshop Pushes for high luminosity ~10 34 and lower and more symmetric energies Simulation for charged  + production, assuming 100 days at a luminosity of 10 34, with 5 on 50 GeV (s = 1000) Pion cross section models: –Ch. Weiss: Regge model –T. Horn: π + empirical parameterization Kaon cross section model: –T. Horn: K + empirical parameterization based on DESY, Cornell, JLab data Do strange and non-strange sea quarks have the same spatial distribution?

Exclusive Generators: φ and ρ 8 Tanja Horn, CUA Colloquium Simulation generates φ and ρ events w/: –Φ: parameterization of σ L based on a calculation by Kroll-Goloskokov including a branching ratio of into K + K - in rate estimate – ρ: parameterization by A. Sandacz based on NMC data, valid for Q 2 >1 GeV 2 [Horn, Weiss 09] Transverse spin x slower quarks move faster x Asymmetry Deformation of transverse distribution by transverse polarization of nucleon –Helicity flip GPD E, cf. Pauli ff [M. Burkhardt] EIC: exclusive ρ and φ production with transversely polarized beam –Excellent statistics at Q 2 >10 GeV 2 –Transverse polarization natural for collider Tanja Horn, MEIC Simulation Group Report, EIC Detector Workshop

4 on 250 GeV4 on 50 GeV diffractive DIS Both processes produce high-momentum mesons at small angles For exclusive reactions, this constitutes our background Diffractive and SIDIS (TMDs) [W. Foreman 09] Tanja Horn, MEIC Simulation Group Report, EIC Detector Workshop

[Horn 08+] recoil baryonsscattered electronsmesons 4 on 250 GeV 4 on 30 GeV  t/t ~ t/E p Θ~√t/E p PID challenging very high momenta electrons in central barrel, but p different 0.2 ° ° 0.2 ° ° ep → e'π + n Exclusive light meson kinematics 10

Tanja Horn, MEIC Simulation Group Report, EIC Detector Workshop 2010 recoil baryonsscattered electronsmesons no Q 2 cut Q 2 > 10 GeV 2 t-distribution unaffected forward mesons: low Q 2, high p low-Q 2 electrons in electron endcap high-Q 2 electrons in central barrel: 1-2 < p < 4 GeV mesons in central barrel: 2 < p < 4 GeV ep → e'π + n Beam divergence Θ~1/√β * Low (J/ Ψ ) vs. high Q 2 (light mesons) – 4 on 30 [Horn 08+] 11

DES at higher electron energies 4 on 305 on on 50 With 12 GeV CEBAF, has the option of using higher electron energies –DIRC no longer sufficient for π /K separation DIRC needs to be complemented by gas Cherenkov or replaced by dual radiator RICH to push the limit above 4 GeV Momentum (GeV/c) Lab Scattering angle (deg) Tanja Horn, MEIC Simulation Group Report, EIC Detector Workshop

Decaying particles: π° Tanja Horn, CUA Colloquium [T. Horn with summer student: K. Henderson] 1° → 35mm / 2m Opening angle is small and requires fine calorimeter granularity –JLab/BigCal: 38x38mm, H1 forward calorimeter: 35x35mm Opening Angle (deg) π° Lab Angle (deg) Separating the π° decay photons is getting more difficult as the energy increases, but pion momenta are low at high Q 2 Similar to π +, but photon opening angle places a constraint on the calorimetry π ° γγ Monte Carlo generates π ° events with subsequent decay –Cross section model based on a parameterization of NMC data π ° Lab Angle (deg) Opening Angle (deg) 3 on 30 5 on on 250 Tanja Horn, MEIC Simulation Group Report, EIC Detector Workshop

Tanja Horn, MEIC Simulation Group Report, EIC Detector Workshop 2010 Decaying particles: ρ° 14 T. Horn with summer student B. Pollack e p ρ ° p ρ ° π + π - ρ°ρ° 14 Q 2 >10 Q 2 >10, x<0.1

15 If DIRC is used, configuration on left side may need adjustment to make space for readout Central detector layout ions electrons EM Calorimeter Hadron Calorimeter Muon Detector EM Calorimeter Solenoid yoke + Hadronic Calorimeter Solenoid yoke + Muon Detector TOF HTCC RICH LTCC / RICH Tracking 5 m TOF (5-10 cm) DIRC (10 cm) ? Tanja Horn, MEIC Simulation Group Report, EIC Detector Workshop Focus on solenoid

Solenoid Fields - Overview ExperimentCentral FieldLengthInner Diameter ZEUS1.8 T2.8 m0.86 m H11.2T5.0 m5.8 m BABAR1.5T3.46 m1.4 m BELLE1.5T3.0 m1.7 m GlueX2.0T3.5 m1.85 m ATLAS2.0T5.3 m2.44 m CMS4.0T13.0 m5.9 m PANDA (*design) 2.0T2.75m1.62 m CLAS12 (*design) 5.0T1.19 m0.96 m Conclusion: ~4-5 Tesla fields, with length scale ~ inner diameter scale o.k. Tanja Horn, MEIC Simulation Group Report, EIC Detector Workshop

General Solenoid Field D B L θ0θ0 B T = B sin θ (from v x B) p T = p sin θ Initial solenoid: B=4T, L=5m, D=2.5m θ 0 = tan -1 (x/L) L’ = (L/2)/cosθ, θ<θ 0 L’ = (x/2)/sinθ, θ>θ 0 Tanja Horn, MEIC Simulation Group Report, EIC Detector Workshop

Formulas B=central field (T) σ rφ =position resolution (m) L’=length of transverse path through field (m) N=number of measurements z = charge of particle L = total track length through detector (m) γ= angle of incidence w.r.t. normal of detector plane n r.l. = number of radiation lengths in detector msc intr Assumptions: circular detectors around interaction point n r.l. = 0.03 (from Hall D CDC) Tanja Horn, MEIC Simulation Group Report, EIC Detector Workshop

dp/p angular dependence Can improve resolution at forward angles by offsetting IP p = 50 GeVp = 5 GeV Tanja Horn, MEIC Simulation Group Report, EIC Detector Workshop

Multiple scattering contribution p = 50 GeVp = 5 GeV Multiple scattering contribution dominant at small angles (due to B T term in denominator) and small momenta Tanja Horn, MEIC Simulation Group Report, EIC Detector Workshop

“Easier” Solenoid Field – 2T vs. 4T? Intrinsic contribution ~ 1/B Multiple scattering contribution ~ 1/B p = 50 GeVp = 5 GeV B=2T B=4T Tanja Horn, MEIC Simulation Group Report, EIC Detector Workshop

Include dipole field p = 50 GeV p = 5 GeV As expected, substantially improves resolutions at small angles Tanja Horn, MEIC Simulation Group Report, EIC Detector Workshop

GEMC (GEant4 MonteCarlo) Tanja Horn, MEIC Simulation Group Report, EIC Detector Workshop EIC GEANT MC will be based on GEMC [M. Ungaro] –Cross section model based on a parameterization of NMC data GEMC can retain a very high degree of commonality between its CLAS12 and EIC implementations –Relies on external field map and geometry services implemented as queries to MySQL databases –The code could be maintained for both applications. SVT CTOF Beamline DC Run (Octobe r 2014) Tilts, Displac ements RUN Geometry server is accessed through a series of PERL scripts –Further information:

EIC GEANT MC Tanja Horn, MEIC Simulation Group Report, EIC Detector Workshop First iteration: understand rate distributions in various parts of the detector –Compare with simple background studies [J. Castilow 09] Solenoid yoke + Hadronic Calorimeter Solenoid yoke + Muon Detector Tracking 5 m Implementation will be done in several steps with increasing levels of sophistication –Cartoon serves as guideline for the implementation

Simulation and Reconstruction Working Group The main goals of the simulation working group is to provide – Event generators for various processes – Fast Monte Carlo to explore acceptance and resolution requirements – GEANT4 based Monte Carlo to study detector resolution and acceptance – Event Reconstruction for GEANT based MC GEANT4 MC will use the standard CLAS12 engine, GEMC. – Flexible design uses external, implementation independent field map and detector geometry servers. – Support for digitizations, etc provides data that can be used for full event reconstruction. – Package will be maintained and developed together with CLAS Tanja Horn, MEIC Simulation Group Report, EIC Detector Workshop 2010

– further info webpage: – Overview and general information WIKI: – Ongoing project information – Working groups EIC Collaboration meeting at Catholic University, July, DC – Info: Weekly project meetings at JLab – Fridays at 9:30am in ARC724 or F324/25 Series of Workshops at the INT, Seattle – Info: 26 Tanja Horn, MEIC Simulation Group Report, EIC Detector Workshop 2010

Summary The is well suited for taking JLab beyond 12 GeV –Excellent tool to access nucleon/nuclear structure A medium energy collider is particularly appealing for measurements requiring transverse targets and/or good resolution and particle id (e.g., TMDs, GPDs). –These processes benefit from high luminosity, excellent polarization, and more symmetric collision kinematics. Matches energy, luminosity, and detector/IR for deep exclusive and SIDIS processes Rapidly Expanding User Community 27 Tanja Horn, MEIC Simulation Group Report, EIC Detector Workshop 2010