Tag Archive | Physics

Fastest Way to Calculate Hadronic Cross Sections

Many of the particle physicists may think that CompHEP is not a proper way of making hadronic calculations. Since in numerical calculations CompHEP treats each subprocess separately, calculation of a process with lots of subprocesses (as it happens usually in calculations for hadron colliders) can be a laborious task. In order to make the task simpler and enable non-GUI calculations both symbolic and numerical programs in CompHEP are equipped with the batch PERL scripts symb batch.pl and num batch.pl correspondingly.

Here’s an example how you can use these scripts:

1 -) Open CompHEP in your working directory as ./comphep

2 -) Enter a scattering process like pb,pb -> t,T.

3 -) Enter C-compiler and complete symbolic calculation.

4 -) You will get the numerical session GUI and see Process, SubProcess, Monte Carlo seesion…etc. Notice that you can only calculate subprocess cross sections here.

5 -) Open a new terminal but don’t close CompHEP numerical session window.

6 -) Open your CompHEP working directory where num_batch.pl and sym_batch.pl are located.

7 -) Write ‘./num_batch.pl -run vegas’

8 -) Write ‘./num_batch.pl -show cs’ and you’ll get the total cross section through all subprocesses.

OR edit process.dat to enter your process and use sym_batch.pl in terminal window to complete symbolic calculations.

Reference: http://arxiv4.library.cornell.edu/pdf/0901.4757v1


Blog Motivation No:1

Buffalos at Fermilab

Buffalos at Fermilab

I was blogging for almost a year about music, webdesign and physics but i decided to write more about high energy physics which is the main area that i am studying on.

It’s weird but the main reason that inspired me about physics blogging is the announcement at Fermilabs webpage:

“Physics is our mission, but buffalo may be Fermilab’s main attraction for visitors. What are buffalo doing at a physics laboratory? (The oft-told tale that they are Fermilab’s equivalent to the canary in the mineshaft, living Geiger counters to warn of radioactivity, is strictly fiction. The Fermilab site does not present a radiation hazard, and Fermilab buffalo do not glow in the dark.) Our buffalo herd carries on a tradition begun by Robert Wilson, the Laboratory’s first director, to recognize and strengthen Fermilab’s connection to our prairie heritage. Wilson brought the first American bison, a bull and four cows, to Fermilab in 1969; and in 1971 the Illinois Department of Conservation gave us 21 more. Today’s herd are descendants of those first animals. ”

A buffalo that glows in the dark would be great logo design for Fermilab. So simple and elegant. But the real danger is that i will mostly remember the Fermilab for these buffalos instead of top quark discovery or other achievements.