Data

(last update of July 2026 — campaign 2026-07)

Location

Campaign 2026-07 introduces the new 9xN energy scheme (5x41, 9x100, 9x130, 9x275 GeV) for the EIC early-science program.

For machine-background-mixed data, see the Machine background (2026-06) section below.

Reconstruction-based analyses can use reco / csv_reco directly.

On JLab ifarm:

/work/eic3/users/romanov/meson-structure-2026-07

On XRootD (open for universities and public)

xrdfs root://dtn-eic.jlab.org
ls /work/eic3/users/romanov/meson-structure-2026-07

Subdirectories (per-energy dirs 5x41, 9x100, 9x130, 9x275; files named msf_ev1000_NNNN.*) :

• afterburner — eg output with crossing-angle + beam effects
• bg_merged — Afterburner + background merged
• dd4hep — DD4hep full simulation (*.edm4hep.root; ~5.0 TB, ~1000 files/energy)
• reco — EICrecon reconstruction of dd4hep (*.edm4eic.root; ~2.2 TB, ~1000 files/energy)
• csv_dd4hep — acceptance / MC-truth CSVs from dd4hep (~21 GB)
• csv_reco — reconstruction CSVs from reco (*.mc_dis.csv, *.reco_dis.csv, *.mcpart_lambda.csv, *.reco_ff_lambda.csv; ~1.2 GB)
• eg-split, eg-hepmc, eg-original-2026-06 — event-generator inputs

1000 events per file (~1000 files per energy)

# available throuhg xrdfs root://dtn-eic.jlab.org
/work/eic/users/romanov/meson-structure-2026-07/eg-hepmc
/work/eic/users/romanov/meson-structure-2026-07/eg-original-2026-06
/work/eic/users/romanov/meson-structure-2026-07/eg-split
/work/eic/users/romanov/meson-structure-2026-07/afterburner
/work/eic/users/romanov/meson-structure-2026-07/bg_merged
/work/eic/users/romanov/meson-structure-2026-07/dd4hep
/work/eic/users/romanov/meson-structure-2026-07/reco
/work/eic/users/romanov/meson-structure-2026-07/csv_dd4hep
/work/eic/users/romanov/meson-structure-2026-07/csv_for_ai
/work/eic/users/romanov/meson-structure-2026-07/csv_reco
/work/eic/users/romanov/meson-structure-2026-07/analysis
/work/eic/users/romanov/meson-structure-2026-07/datasets-no-background

Per-energy .root counts / sizes:

Energy	dd4hep (.edm4hep.root)	reco (.edm4eic.root)
5x41	998 (647 GB)	998 (472 GB)
9x100	1000 (1.4 TB)	999 (718 GB)
9x130	1000 (1.7 TB)	1000 (421 GB)
9x275	1000 (1.4 TB)	1000 (630 GB)

Machine background (2026-06)

Machine-background-mixed data comes from campaign 2026-06, where the afterburned signal is mixed with the official ePIC background cocktails (synrad, ebrems, ecoulomb, etouschek) via SignalBackgroundMerger into 2 µs timeframes (one signal per frame), then run through npsim with status-offset flags. See Backgrounds in ePIC simulation for the full mechanism.

(!) The background datasets use the old energy scheme 10x100, 10x130, 18x275 (5x41 is skipped) and 5000 events per fil, named k_lambda_{beam}_5000evt_NNNN.*.

On JLab ifarm, under /work/eic3/users/romanov/meson-structure-2026-06:

• bg_merged — SignalBackgroundMerger output (*.bg.hepmc3.tree.root; the merged input to npsim; ~5.0 TB, 200 files/energy)
• dd4hep-background — DD4hep on the background-merged input (*.edm4hep.root; ~12 TB)
• reco-background — EICrecon reconstruction of dd4hep-background (*.edm4eic.root; ~4.1 TB, partial)
• csv_dd4hep-background — acceptance / combinatorics CSVs from dd4hep-background (~9.1 GB)

Per-energy .root file counts (background):

Energy	bg_merged	dd4hep-background	reco-background
10x100	200	133	68
10x130	200	200	43
18x275	200	200	107

xrdfs root://dtn-eic.jlab.org
ls /work/eic3/users/romanov/meson-structure-2026-06/reco-background

Campaign 2026-06 also produced non-background flavors (dd4hep-official, dd4hep-saveall, dd4hep-stv, and their reco/csv) — see the campaign 2026-06 page.

Accessing Data with XRootD

The data is available remoutly through XRootD via:

root://dtn-eic.jlab.org

To browse the available files one can use xrdfs command:

xrdfs root://dtn-eic.jlab.org
ls /volatile/eic/romanov/meson-structure-2026-03/reco

To download files:

xrdcp root://dtn-eic.jlab.org//volatile/eic/romanov/meson-structure-2026-03/reco/5x41-priority/k_lambda_5x41_5000evt_001.edm4eic.root ./

To use directly in scripts:

# Both uproot and pyroot can work with links directly 
# if XRootD is installed in the system
import uproot
file = uproot.open("root://dtn-eic.jlab.org//volatile/eic/romanov/meson-structure-2026-03/reco/5x41-priority/k_lambda_5x41_5000evt_001.edm4eic.root")