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Manuscript Title: The dipole model Monte Carlo generator Sartre 1
Authors: Tobias Toll, Thomas Ullrich
Program title: Sartre 1.0
Catalogue identifier: AESP_v1_0
Distribution format: tar.gz
Journal reference: Comput. Phys. Commun. 185(2014)1835
Programming language: C/C++.
Computer: Any with standard C/C++ compiler.
Operating system: Tested on Linux and MacOS.
Keywords: QCD, small x, diffraction, ep, eA, vector mesons, DVCS, DIS, UPC.
Classification: 11.1, 11.2, 11.6.

External routines: ROOT and GSL for numeric algorithms and other various tasks throughout the program. BOOST for multi-threaded integration (optional), GEMINI++ for nuclear break-up and CUBA for multidimensional numerical integration (the latter two supplied with the program package). Uses cmake for building and installing.

Nature of problem:
Simulate diffractive exclusive vector meson and deeply virtual Compton scattering (DVCS) production in electron-nucleus scattering where the exchanged virtual photon interacts coherently with a large region of the nucleus. To calculate the cross section correctly it has to be averaged over all possible configurations of nucleon positions within the nucleus.

Solution method:
To make an arithmetic average of the quantum mechanical amplitude over nucleon configurations numerically and store the result in look-up tables.
Implemented processes: The following processes can be simulated:
e + pe′ + V + p′
e + Ae′ + V + A′
p + pp′ + V + p′
p + Ap′ + V + A′
A + AA′ + V + A′

where V is a J/ψ, φ, or ρ vector meson, or a real photon (DVCS). All processes are mediated by a virtual photon and a pomeron. The present version is applicable for these processes at future electron-hadron colliders, such as the EIC and the LHeC, as well as HERA, RHIC, and the LHC.

The program is reliable for process at xp < 10-2, and large β = x/xp.

Running time:
On a MacBook Pro with a 2.66 GHz Intel Core i7 processor, event generation takes ~ 0.1 ms/event without correction and nuclear breakup, ~ 0.2 ms/event with the recommended corrections switched on, and ~ 6 ms/event when running with corrections and nuclear breakup.