The dipole model Monte Carlo generator Sartre 1

Abstract We present the Monte Carlo generator Sar t re for simulating diffractive exclusive vector mesonproduction and DVCS in electron–proton, electron–ion, and hadron–hadron collisions. Program summary Program title: Sartre 1.0 Catalogue identifier: AESP_v1_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AESP_v1_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing provisions: GNU General Public License, version 2 No. of lines in distributed program, including test data, etc.: 703313 No. of bytes in distributed program, including test data, etc.: 179406465 Distribution format: tar.gz Programming language: C/C++. Computer: Any with standard C/C++ compiler. Operating system: Tested on Linux and MacOS. 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 multi-dimensional numerical integration (the latter two supplied with the program package). Uses cmake for building and installing. Nature of the problem: Simulate diffractive exclusive vector mesonand 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 + p → e ′ + V + p ′ e + A → e ′ + V + A ′ p + p → p ′ + V + p ′ p + A → p ′ + V + A ′ (1) A + A → A ′ + 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. Restrictions: The program is reliable for process at x p 1 0 − 2 , and large β = x / x p . Additional comments: The distribution file for this program is over 178 MB and therefore is not delivered directly when download or E-mail is requested. Instead an html file giving details of how the program can be obtained is sent. Running time: On a MacBook Pro with a 2.66 GHz Intel Core i7 processor, event generationtakes ∼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.