Powerweek 2011: pQCD and Energy loss
Software requirements
All students are expected to bring a laptop with the following software installed:
- ROOT A recent version of ROOT
You can install ROOT from source or precompiled, see instructions on
the ROOT website. Please make sure that the compilation of macros with
ACliC works.
- AliRoot is not necessary. We will use AliFastGlauber
for Glauber calculations and AliQuenchingWeights for energy loss, but
these can be compiled standalone and loaded. Just download the source
from SVN.
- LHAPDF see the LHAPDF website for instructions. On my laptop, the default configuration uses too much memory during compilation, so I used the options '--enable-low-memory -enable-pdfsets=mrst,cteq'. Make sure that the example programs in the example directory are compiled. You need to download PDF sets separately, using the get-dataset script in the bin directory (CTEQ6 is a good choice). The PDF sets should be placed in <install-dir>/share/lhapdf/PDFsets. The C++ interface is described here. During the hands-on sessions, you will need to write and compile your own programs (look at examples/CCtestx.cc for guidance). You can adapt this Makefile to suit your needs.
- Fragmentation function libraries We will use the KKP and AKK fragmentation functions. You can download the files libkkp.so libakk.tar.gz. Unpack them in your working directory directory and compile them (cd kkp; ./make; cd ../AKK; ./make). Use the macro plot_frag.C to test the KKP package.
We will use ROOT as the main plotting package and C++ as the default
programming language. It is important that you have some working
experience with ROOT and C++. In principle, the exercises can also be
performed using another programming language and plotting package; if
you have extensive experience with another set of tools, and would
prefer to use those, please contact us in advance, so that we can
discuss whether this is feasible.
Hands-on exercises
A document with hands-on exercises can be found here (still under construction).
The pQCD matrix elements are implemented in this function
Solution: The parton production spectra are calculated in calc_xsec4.C (compile with LHAPDF, using the makefile)
Day 3
DGLAP evolution macro
Day 4
Solutions:
Macro to convolute parton spectrum with fragmentation function and plot the result
Macro to plot the energy loss distribution and calculate Rn
Macro to convolute parton spectra, energy loss and fragmentation. This macro needs utils.C and convolute.C to function.
Lecture slides
Useful literature (papers)