I have not updated the news for artemide for several months by now, which is a significant fault, because already for three months artemide is ver.2.00. In fact, I have just committed ver.2.01. It is not yet released since I wait for responses from "testers."  Let me mention the main changes is order.

artemide v2.00

It is a critical architectural update, which was required for a long time. It touches absolutely all modules (although it does not touch numerics). Starting from this version, all modules on the initialization stage read the ''constants-file'', and load all necessary information from it. It was like that in earlier versions, where modules read values of some global constants from the file. However, now, the modules read (literally) all initialization information from this file, including, e.g., names of PDF sets and perturbative orders. Main reasons why it is better than earlier:

-- No, need to recompile artemide each time you consider another PDF set, or SIDIS instead of DY. Now, the recompilation is only necessary if NP-model is changed.

-- Version compatibility. The external file makes the transition between versions much-much easier. In principle, only constants-file should be updated to make older version work with a new one (there is a special code for it).

-- Snapshot for fits. Constants-file effectively saves the full current configuration of artemide, which can be used in the future.


In addition to the new initialization system, I have written two modules: aTMDe_setup and aTMDe_control. They are separate from the main artemide code and completely utilitarian.  aTMDe_setup reads, modifies and writes constants files (it also contains default options). In particular, it can update an older version of constants-file to an actual one. aTMDe_control is an interface to artemide. It loads all modules required by constants-file, and pass commands to a proper module in proper order. So, there is no need to worry is all loaded in proper order and which modules to include in your code. You can operate only with aTMDe_control (this is the suggested option).

There are several other modifications, which worth to mention:

-- The models now contain b*-function. I.e., the function which replaces b in matching coefficient. So, b*-prescription can be used.

-- Fixed a memory leak error, in bin-integration routine. It probably caused to a ''segmentation fault'' error experienced by some users.


artemide v2.01

This update introduces several new options and a whole new module: lpTMDPDF.

-- Module lpTMDPDF evaluates linearly polarized gluon TMDPDFm including NNLO matching (paper will appear soon).

-- Added a recently found (not yet published) exact solution for the special zeta-line (defined in terms of non-perturbative rapidity anomalous dimension). It is strange why I have not realized earlier that such a simple solution exists.

-- Added pi-resummation option for Drell-Yan processes

-- Added Higgs-production cross-section in TMD factorization. However, I have not added any Higgs-decay mode yet.

-- Several bugs fixed, + a bunch of new processes added (e.g., pion induced Drell-Yan).

I have not updated the news for artemide for several months by now. However, it does not mean that the development was idle. There are several important announcements.

1)  Together with the paper [1902.08474], I release the new version of artemide - ver.1.4. There are plenty of changes, but the majority of them are structural. Now, it runs in parallel for multiple data-inputs.  So, it is incompatible with earlier versions.  There are also: asymmetric cuts, several new processes, and bug-fixing. List of changes can be found in manual.

2) Artemide is made on Fortran, which is not always convenient. Now, we have harpy (Hybrid ARtemide PYthon). It is a module which wraps some artemide functions, and which is compilable by f2py (the Fortran-linking library for python). So, you can use artemide with python. It does not inherit full functionality, but main routines are in, and extra could be added. Harpy is in the early stage of development, and I have big plans on its extension. Nonetheless, it is already functional, e.g., a part of work for paper [1902.08474], was made with its help. If you have suggestions on what to add to harpy, and how to develop it better, please, write to me.

3) Finally, since it is much more convenient to have a repository for code publishing, I have made the git-repository for artemide. Here, you can find the latest release and development version. It also contains harpy, manual, and some examples.

Link to repository: https://github.com/VladimirovAlexey/artemide-public

arXiv reference

It took almost one year to make this extraction. I am proud that it is finally on arXiv. It is a real achievement to describe so many and so different experiments simultaneously. It requires all parts of the construction to work together and to work properly. There are still issues, but all of the minor issues and should not influence the general picture to much. I am sure; we will fix them eventually.

Abstract: We evaluate the light-cone operator product expansion for the unpolarized transverse momentum dependent (TMD) operator in the background-field technique up twist-3 inclusively. The next-to-leading order (NLO) matching coefficient for the Sivers function is derived. The method, as well as many details of the calculation, are presented.

The abstract is short, but the work is not! In fact, it is the first calculation of such kind in physics of TMDs, and in this article, we look at many aspects of TMD distributions from a different perspective. Due to it I specially made the article as simple and pedagogical as I could. You even can find it boring in some places, but you can also give it to your students (well... master students). Here is arXiv-reference. I have also added working notes on it to supplementary materials (entry 8).

The arTeMiDe v1.31 is available on its website.

The main change in comparison to the ver.1.3 is the update of integration-over-b routine, which is now more accurate and controllable. It is also split into a separate module, and thus cross-section modules are also updated. Such re-structure allowed to introduce a new structure for process-definition. It became more flexible and simple. Unfortunately, I have not yet updated TMDX_SIDIS module, thus if you need SIDIS cross-section use previous version. There are also many small fixes. All these changes are explained in the manual.

It is an intermediate version that will be soon updated to 1.32. The reason to publish an intermediate version is that it is perfectly stable (which has been already tested by several people), while the next update touches the core of arTeMiDe - the griding of TMD distributions. Hope, it will not take too long to update and test the next version.