LanHEP installation and Pre-exercies

I recommend you to do the following pre-exercise. It would take less than 15mins to do this pre-exercise if you successfully finish the installation of LanHEP and CalcHEP.

Philosophy of using LanHEP (in my personal point of view)

1. It would be always good to double-check results with various programs.

   1. • LanHEP started to support UFO ( Though "UFO output (preliminary, not tested well)", which means that NO Guarantee)

2. LanHEP uses a gcc complier.

3. To use LanHEP to write down a model is as simple as to write down a paper using a LaTeX.

Supported environments : "The LanHEP software is written in C programming language."

1. Linux

2. OS/X: Need to install Xcode (to get a gcc)

   • If you need a gfortran (for various Monte Carlo simulations), it would be better to get a gnu gfortran

3. MS-Windows (not supported)

   • "A" way to go: Install a virtual machine ( A free program: Virtual Box) and install the Linux on the virtual machine. This would be the best solution for you to run various M.C simulations on MS-window based machine.

Installation instructions:

1. Download a Lanhep program HERE.

2. Make a proper directory for Lanhep installation. (For example mkdir $HOME/MC4BSM )

3. Move the downloaded file to the directory that you just made.

   • Let's suppose that you made MC4BSM directory under your $HOME directory, and you downloaded "lhep315.tar" file in the '$HOME/Downloads" directory, then you can move the file into your MC4BSM folder by typing

     • mv $HOME/Downloads/lhep315.tar $HOME/MC4BSM/.

4. Unzip "lhep315.tar" file by typing

   • • tar -xvf lhep315.tar

   • It will generate lanhep315 folder under $HOME/MC4BSM.

5. Go to lanhep315 directory and read "README" file

6. compile the program by typing

   • • make

7. Happy to use LanHEP!

Pre-workshop exercise

1. Make sure that you installed LanHEP properly.

2. Read "README" file in your LanHEP directory.

3. Read a manual:

   • Go to manuals directory under your LanHEP directory.

   • Read Section 1 in the manual30.pdf (This manual30.pdf is the same as the one in the arxiv.)

4. Read simple models that are already provided in mdl directory.

   • Use any text-viewer to open qed.mdl file.

   • Q1) What are the defined particles inside this model file?

   • Q2) Can you tell me what is the unit of mass in this file?

   • Q3) What is the relation between e1 and E1 ?

   • Q4) Can we replace (or merge) "derivative" with "covariant-derivative" ? (hint: section 3.4 in the manual.)

5. Compile qed model file by your own:

   • It would be better to make a separate directory for the "complied" model. Let's make the directory for example inside your lanhep directory (If you are in the mdl directory, please go the upper directory by typing cd ..

     • mkdir QED

   • Compile qed.mdl file by using a command lanhep as follows,

     • ./lhep -OutDir QED mdl/qed.mdl -CalcHEP

     • If you just type ./lhep then you will see the various options.

     • You will get a complaint: "Warning: property 'pdg' is not defined for particle 'e1' ", then how can we fix it?

   • Fixing the above warning:

     • pdg is the number of various particles to identify it in M.C. These PDG numbers are well explained in Pythia manual Section 5.1 and Table 4 on the page 71.

   • Q5) What would be the pdg number for the particle "e1" in a qed model file?

   • Open calchep.rc file in mdl folder. Then you will see how pdgs are defined for various particles. Add e1=the answer for Q5) in this file and save it. (In the onsite exercise, we will choose the other way to put PDG.)

   • Delete old files in your QED folder and compile a model file again using lhep.

6. Put this model inside CalcHEP

   • This exercise would be non-trivial. To do this, you should finish the exercises in CalcHEP section.

   • Generate e1, E1 -> e1, E1 process and look at the feynman diagrams to check whether we did a good job or not.

7. DONE! Now you are ready to go. Thank you for your time.

Ready to go to MC4BSM onsite exercise HERE