Yellow Report Physics Inclusive Reactions

Welcome to the inclusive reactions group! Our charge is to "advance the state of documented (i) physics studies and (ii) detector concepts in preparation for the EIC. This will provide the basis for further development of concepts for experimental equipment best suited to the EIC science needs. The effort should conclude in a Yellow Report that summarizes the findings." The Inclusive Reactions section of the Yellow Report will be approximately 15 pages total and is due by the end of calendar year 2020. For details and a list of resources please refer to: http://www.eicug.org/web/content/yellow-report-initiative.

Meetings

We hold regular meetings every Tuesday at 10:30 am EDT time.

• Indico Schedule Indico Link
• Inclusive Google Group Inclusive Google Group

Focus Areas & Workflow

The inclusive reactions group covers a wide range of physics channels, ranging from spin-averaged and spin dependent nucleon parton distribution functions (PDFs), to nuclear PDFs, non-linear QCD and higher twist effects, Beyond the Standard model and CPT and Lorentz violating measurements.

Theoretical Interpolation Tables

A git repository has been set up to store the theoretical input tables. Please see the readme on how to contribute : https://github.com/JeffersonLab/txgrids.

Vertex Level Monte Carlo Simulation Generation

A complete list of the available generators is compiled on the EIC simulations page.

Fast Simulation Detector Effects

The IRG plans to use the EIC Smear package to implement detector resolutions. Detailed instructions on how to setup your environment and run the EIC-Smear package at BNL, JLAB or in a singularity container are available here

electron PID studies

This section summarizes the electron PID studies performed by Hanjie Liu and Sasha Bazilevsky.

Hanjie used pythiaRHIC with a minimum Q2 of 1E-6 GeV to estimate the number electrons and negatively charged pions as a function of momentum for detector matrix eta bins. Radiation effects are included in this study and all electrons, including those produced in pair-symmetric processes, are included.

5x41 GeV	5x100 GeV
e+p Beam 5x41 GeV	e+p Beam 5x100 GeV
10x100 GeV	18x275 GeV
e+p Beam 10x100 GeV	e+p Beam 18x275 GeV

Sasha performed a GEANT Based PID study that included simple cluster algorithms for e/pi discrimination.

Kinematic coverage files

This section summarizes the kinematics studies of the Inclusive Reactions working group. We have simulated the following processes:

Inclusive neutral current electron-proton scattering

• Species and energies used: e+p 5+41, 5+100, 10+100, 18+275 GeV
• Generator used: pythia6
• Input Cards and Plotting Macro: 5+41 card, 5+100 card, 10+100 card, 18+275 card, Macro
• ROOT Files: '/gpfs02/eic/baraks/pythia/outfiles/yellow_report/' on BNL RACF machines
• Q² > 0.5 GeV²
  
• Contact : Barak Schmookler

5x41 Scattered Electron Only	5x100 Scattered Electron Only
10x100 Scattered Electron Only	18x275 Scattered Electron Only

5x41 All detected electrons	5x100 All detected electrons
10x100 All detected electrons	18x275 All detected electrons

• Plots for other particle types: protons, neutrons, photons, all hadrons
• Plots for 10 GeV² < Q² < 100 GeV²: scattered electron, all electrons, protons, neutrons, photons, all hadrons
• Plots showing event counts on Q2 vs. x plane: 5+41, 5+100, 10+100, 18+275, macro 1, macro 2
• Plots made using Djangoh Event Generator: scattered electron, all electrons, protons, neutrons, photons, all hadrons, input cards and plotting macro, ROOT Files: '/eic/data/baraks/dis-reconstruction/djangoh/outfiles/yellow' on BNL RACF machines

Inclusive neutral current electron-nucleus scattering

• Species and energies used: e+Au 5x41, 10x110, 18x110 GeV
• Generator used: BeAGLE ( BeAGLE Normalization )
• Input Cards: 18x110 (Others energies similar)
• ROOT Files: Located on BNL RACF machines
• Q² > 0.5 GeV²
  
• Contact : Barak Schmookler and Dmitriy Kim

• Plots for scattered electron, all final-state electrons, protons, neutrons, photons and hadrons can be found here.

Inclusive charged current electron scattering

• Species and energies used: e+p 18+275 GeV
• Generator used: Djangoh
• Contact : Xiaoxuan Chu

Photons	Charged Hadrons+Neutron

Monte-Carlo Validation

Comparison to HERA NC Data

Generator-level comparisons of the Djangoh event generator to NC HERA data can be found here and here. Comparison of both the Pythia6 and Djangoh event generators - as well as state-of-the-art theory calculations at LO, NLO and NNLO - to the HERA data can be found here and here. For the results shown in the last two links, the monte-carlo input cards can be found here and here; the plotting scripts can be found here and here.

Inclusive neutral current electron-proton scattering at EIC energies

Comparison of the Djangoh event generator to theory calculations at EIC energies can be found here and here. Comparison of both the Pythia6 and Djangoh event generators to theory calculations at EIC energies can be found here for all EIC energies: 5x41, 5x100, 10x100, 18x275. For the final link, in addition to the calculation of the average cross section in each bin from the monte-carlo generators as shown on pages 1 and 2, the monte-carlo cross sections after the application of bin-centering corrections are shown on pages 7-10.

For the results shown in the last set of links, the monte-carlo input cards are the same as the ones shown in the kinematic coverage section; codes to create the various plots can be found in the folder here. As can be seen in the input files, the Djangoh simulation was performed using the cteq61.LHgrid (10150) LHAPDF5 grid, while the Pythia6 simulation was performed using the cteq6ll.LHpdf (10042) LHAPDF5 grid. The Pythia6 simulation was repeated using the cteq61.LHgrid PDF grid (i.e. the same one used for Djangoh); as shown here for the highest energy setting, the cross section results are more consistent between the two monte-carlo programs when the same input PDF grid is used.

Resolution and Bin Migration

It is important to understand if the proposed detector packages provide sufficient resolution for the kinematic variables, y, x and Q² and how this resolution affects the bin migration.

Resolution effects are typically studied by making plots of the fractional deviation (R-G)/G of the reconstructed variable (R) vs the generated variable (G).

1. Δy/y_G vs (y_G, x_G, Q²_G)
2. Δx/x_G vs (y_G, x_G, Q²_G)
3. ΔQ²/Q²_G vs (y_G, x_G, Q²_G)

Bin migration effects are typically studied by looking at the the acceptance, backgrounds, purity and stability for each kinematic bin.

1. Acceptance : The fraction (f_acceptance) of events generated in a given (y_G, x_G,Q²_G)bin that are reconstructed in the detector. The acceptance encapsulates effects due to a limited fiducial volume, as well as efficiencies within that fiducial volume.
2. Background : The fraction (f_background) of events reconstructed in given (y_R, x_R, Q²_R)bin that do not match to a generated event.
3. Stability: The fraction of events generated in a given bin i that were reconstructed in the same bin i → S(i) = N_gen&reco(i)/N_gen(i). The stability reflects the bin migration out of a generated bin(y_G, x_G,Q²_G).
4. Purity : The fraction of events reconstructed in a given bin i that were generated in the same bin i→ P(i)= N_gen&reco(i)/N_reco(i). The purity reflects the bin migration into a reconstructed bin (y_R, x_R,Q²_R).
   

The following sections demonstrate Stability and Purity for events generated with either Pythia or Djangoh and smeared with the detector group settings for EICsmear. In each case the goal is for Purity and Stability to exceed 30% for all bins.

Inclusive neutral current electron scattering

• Species and energies used: e+p 5+100, 10+100, 18+275 GeV
• Scattered electron kinematics used for reconstruction
• Generator used: Djangoh
• Contact : Xiaoxuan Chu

Purity NC 5x100

Purity NC 10x100

Purity NC 18x275