
Hiren H. Patel
Overview
PackageX is a Mathematica package to obtain compact analytic expressions for oneloop integrals in higher order calculations of relativistic quantum field theory in 4 spacetime dimensions.
Technical features
 Compute oneloop integrals with up to three propagators
 Obtain analytic expressions for UVdivergent, IRdivergent and finite parts of oneloop dimensionally regulated integrals
 Get results for any kinematic configuration (at zero external momentum, at physical threshold, etc.) with real masses and external invariants.
 Numerical evaluations always consistent with the +iε prescription
 Works for arbitrarily highrank tensor integrals
 Calculates traces of products of Dirac matrices in d dimensions
User interface features
 Complete set of help pages (accessed via the Documentation Center inside Mathematica)
 Readable and intuitive input
 Output easily manipulatable (copy/paste friendly) and readily evaluated numerically
Featured code snippets

Compute a rank1 tensor integral: 
In[1]:= 

Out[1]= 


Compute the trace over gamma matrices: 
In[2]:= 

Out[2]= 


Calculate the Higgs to two gluons decay amplitude 


In[3]:= 

Out[3]= 

Reference
PackageX was developed after several long years of tedious work. Please include the following citation if PackageX was useful for your publication.
Hiren H. Patel, Comput. Phys. Commun. 197, 276 (2015), ePrint: arXiv:1503.01469
License
PackageX is closed source and distributed under the standard CPC license agreement.
Latest release
v1.0.4: (October 12, 2015) Download
 Scalar C function
pvC[0,0,0,0,m^2,0,m,0,0] now reduces to the correct analytic expression by LoopRefine (thanks, Benjamin Lillard).

Simplify and FullSimplify no longer tries to bring the divergent and finite parts of LoopRefine output under a common denominator proportional to ϵ .
v1.0.3: (September 5, 2015, second release September 20, 2015) Download
 Fixed bug in
LoopIntegrate that lead to excessive evaluation times for integrands that used Projector due to uncontracted Lorentz fourvectors. (thanks, Shanmuka Shivashankara).
 Various underthehood improvements.
 (Second release) Fixed typos in Wolfram documentation help pages for
LoopIntegrate and ϵ , and tutorial (thanks, Gregory Ovanesyan and Nicholas Rodd).
v1.0.2: (June 23, 2015) Download
 Added option
Organization to LoopRefine . Results can now be organized by tensor structures.
 Improved performance of
LoopRefine ; (e.g. LoopRefine no longer sometimes hangs when the option ExplicitC0 > All is set).

Transverse and Longitudinal no longer throw errors when three arguments are passed to them (Transverse and Longitudinal are no longer Listable ).
 Fixed typos / clarified certain points in Wolfram documentation help pages.
v1.0.1: (March 24, 2015) Download
 Scalar C function
pvC[0,0,0,0,0,s,0,0,m0] now reduces to the correct analytic expression by LoopRefine (thanks, Vladyslav Shtabovenko).

FrontEndObject::notavail warnings are no longer issued when PackageX is loaded without a front end.
v1.0.0: (March 6, 2015) Download
Compatibility
Any computer running Mathematica 8.0.4 or higher.
Installation Instructions
Uncompress downloaded file, and copy the PackageX folder (/X) with all its contents to the folder $UserBaseDirectory/Applications/. See the tutorial for details.
Tutorial
Get started with the tutorial (September 20, 2015).
