GPDs

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Next-generation studies of partonic spatial imaging at an Electron-Ion Collider

The main purpose of the working group:

  • perform impact dtudies via global fits of different GPDs models and probes;
  • create a powerful and flexibale software tool for the EIC users community that would ensure propagation of knowledge;
  • use the GPD-based tables of Compton form factors (CFFs) calculated within this common framework to seed a novel Monte Carlo generator for DVCS and meson production, featuring second order initial- and finalstate radiative effects;
  • employ this novel generator to test reconstruction of kinematics and carefully define detector requirements for exclusive processes, a particularly timely study at this stage;
  • assess the feasibility of extracting the D-term from precise measurement of differential cross sections.

The group is typically meeting remotely every other Monday at 10:30am EDT (New York time zone), using bluejeans.

Meetings AGENDA

INDICO PAGE https://indico.bnl.gov/category/267/

How to connect to meetings

Meeting URL
Meeting ID
383 476 545

Want to dial in from a phone? Dial one of the following numbers:
+1.408.740.7256 (US (San Jose))
+1.408.317.9253 (US (Primary, San Jose))
Enter the meeting ID and passcode followed by #

Connecting from a room system?
Dial: bjn.vc or 199.48.152.152 and enter your meeting ID & passcode

Shared Software and Tools

PARTONS Project

MILOU Generator

Old Code by McDermott, used to create tables of CFFs and GPDs

MILOU with 3d tables

The MILOU code has been copied to CEA GitLab: https://drf-gitlab.cea.fr/milou/milou (authentication required). This git project contains several branches:

  • the development branch is 'master' (it is also the default branch)
  • the original/initial code is stored in 'original' branch (this branch is protected - no one can modify it)
  • '3d_tables' branch contains the version being under development where (xB, Q2, t) DVCS Compton form factors are used (note: this version is under development and not fully tested).

To clone a given branch use either:

    git clone git@drf-gitlab.cea.fr:milou/milou.git -b _branch_name_

or

    git clone https://drf-gitlab.cea.fr/milou/milou.git -b _branch_name_

for either ssh or https authentication. Here, '_branch_name_' is the name of branch to be cloned.

New features and options of MILOU with 3d tables:

  • uneccecery files are removed.
  • makefiles are updated.
  • 2d interpolation method is replaced by 3d version being a part of CERNLIB.
  • 'ITFORM 8' enables t-dependence as encoded in 3d tables. Other values of 'ITFORM' enforce MILOU to probe the tables at t=0 and to apply t-dependence as indicated by the set value - this allows to keep the backward compatibility.
  • the size of 3d tables is indicated to MILOU by 'NXGRID', 'NQGRID' and 'NTGRID' options (the last one is new).
  • 3d tables are populated with CFFs generated using PARTONS with GK GPD model (at this moment only LO is available)