HEPMDB - User contributions [en-gb]

HEPMDB

2013-08-23T11:56:41Z

Jblamey:

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If you are new here, you should start with the [[FAQ]].

What is HEPMDB?

The High Energy Physics Model DataBase (HEPMDB) was created to facilitate the connection between high energy physics theory and experiment, to store and validate theoretical models, and to develop a dictionary of the model signatures which identifies the fundamental theories responsible for signals expected at the LHC.

HEPMDB is also designed to collect different signatures of its models and their respective experimental efficiencies. Using this information, HEPMDB will be able to compare its Beyond Standard Model (BSM) predictions with LHC data. In doing so, HEPMDB will be able to discriminate the underlying theory.

The database is in the development stage and your input in the 'Forum' section is highly appreciated. The database collects particle physics models. These models are supposed to be public and represent themselves as a set of Feynman Rules which can be expressed in the input form of any matrix element generator such as CalcHEP, CompHEP, FeynArts, Madgraph, SHERPA, WHIZARD. HEPMDB has an entrance for Model authors -- 'Authors' -- where Authors can test and validate their models.

To become an 'Author' you should register in the 'Register' section. 'Authors' are welcome to upload the LanHEP or FeynRules sources of their models.

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[[File:Tt main.png|500px]]
[http://www.proofreading247.co.uk Proofreading]
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HEPMDB

2013-08-23T11:56:19Z

Jblamey:

CalcHEP reference

2013-08-23T08:56:03Z

Jblamey: /* Process */

Here is the <tt>CalcHEP</tt> batch mode reference. You should find description for every possible parameters the batch mode accepts except if it is redondant with some <tt>HEPMDB</tt> function.

This document is organised as follows: entries concerning similar or close information are gathered together. Each subsection is a parameter name. Sometimes only the main parameter is in the subsection title but the other subparameters are described in the same subsection.

__TOC__

== Model information ==
=== Model ===
This line corresponds to the model used. When using <tt>HEPMDB</tt>, each batch file is associated with a specific model. As a consequence, the default value of this line should not be changed.

=== Gauge ===
<tt>CalcHEP</tt> is able to use two different gauges for computation: Feynman gauge and unitary gauge. Some models require a specific gauge. We recommand leaving the default value for this.

=== Model changed ===
Each time the batch interface is run, it checks initially whether or not the subprocess numerical code exists. If it does, <tt>CalcHEP</tt> reuses the code and skips the often long process of code generation. If the code does not already exist, the numerical code is then generated and added to the library. If the model changed, the numerical codes are regenerated as appropriate.

== Process description ==
=== Process ===
Using the <tt>process</tt> keyword, it is possible to specify which process to compute. Multiple processes can be required.
The general syntax is:
<center><tt>Process: P1 [,P2] -> P3, P4 [,P5...]</tt></center>
This is in the form:
incoming particles <tt>-></tt> outgoing particles. Particles can be particles from the model you are using or composite particles. It is recommended that the number of outgoing particles does not exceed 6.

=== Decay ===
It is possible to specify decays for the outgoing particles. Each decay will be written as follow:
<center><tt>Decay: P -> P1, P2 [,P3...]</tt></center>
Decays will automatically be connected to outgoing particles if possible. Decays will even be connected with one another.

Important note: make sure the same decay does not appear twice.

=== Composite ===
When specifying processes and decays, you can use composite particles, ''i.e.'' labels that refer to various possible particles. This is particularly useful when colliding protons or when studying jets.

The syntax is:
<center><tt>Composite: label=P1 [,P2...]</tt></center>

=== Remove ===
Sometimes, only specific processes will be of interest. It is possible to tell <tt>CalcHEP</tt> which particle you do not want as virtual particles in the processes.
The syntax is:
<center><tt>Remove: P1 [,P2...]</tt></center>

== Beam description ==
=== pdf1/pdf2 ===
=== p1/p2 ===
These two parameters define the energies of the beams. When using pdf, it can also be used as an input parameter for the pdf.
For instance, when using proton photon, this would corresponds to the energy of the initial proton.

== Model parameters ==
=== Parameter ===
It is possible to change some parameters of a model using <tt>Parameter</tt> keyword. The parameters are model specific.
Here is an example for selecting the elementary charge in the standard model:
<center><tt>Parameter: EE=0.31</tt></center>

=== Run parameter ===
It is usual for a model to have some free parameters not completely fixed by experiment.
For that kind of situation, you have the possibility to run several times the same computation with a different value for a specific parameter.

In order to use this possibility, you have to write four consecutive lines.
The first one specifies which parameter to study. To study the Higgs mass using the standard model, you would write:
<center><tt>Run parameter: Mh</tt></center>
Then you must specify the initial value and the increase of the value between each run:
<center><tt>Run begin: 100</tt></center>
<center><tt>Run step size: 10</tt></center>
Finally, the number of steps is defined by:
<center><tt>Run n steps: 6</tt></center>
So, with these specific lines, you will get 6 runs using the following value for the Higgs mass: 100, 110, 120, 130, 140, 150.

It is possible to mark several parameters for running. But it is only possible to explore hyperrectangle in the parameter space.

== QCD parameters ==
=== alpha Q ===

== Cuts ==
=== Cut parameter ===
=== Cut invert ===
=== Cut min/max ===

== Kinematics and regularization ==
=== Kinematics ===

In this part of the batch file the user needs to specify which kinematics are needed. The numbers in the kinematics refer to the particles in the process in order. For example, 12 relates to the first and second particles in the process. Here is an example of some kinematics:
<center><tt>Kinematics : 12 -> 34, 56</tt></center>
<center><tt>Kinematics : 34 -> 3 , 4</tt></center>
<center><tt>Kinematics : 56 -> 5 , 6</tt></center>

=== Regularization momentum ===

Applying regularization means that the phase space is adjusted so that resonances are properly accounted for. Applying regularization will mean that the result is far more accurate.

There are four lines needed in the batch file for each resonance. They are:
<center><tt>Regularization momentum: </tt></center>
<center><tt>Regularization mass: </tt></center>
<center><tt>Regularization width: </tt></center>
<center><tt>Regularization power: </tt></center>

== Events ==
=== Number of events (per run step) ===

This is totally up to the user and what he/she wishes to calculate. Please not that this number of events are being created for each run step. If events are not needed at all, please set this to 0.

=== Filename ===

This is self-explanatory.

== Parallelization ==
=== Parallelization method ===
=== Max number of cpus ===

The maximum number of cpus depends on the computer/cluster you are about to run this batch file on. Typically, this value is 4, 8 or 12.

=== sleep time ===
=== nice level ===

== Vegas session ==
=== nSess_1/2 ===

Normally, 5 should suffice.

=== nCalls_1/2 ===

A typical value would be 100,000.

CalcHEP reference

2013-08-23T08:55:49Z

Jblamey: /* Process */

Here is the <tt>CalcHEP</tt> batch mode reference. You should find description for every possible parameters the batch mode accepts except if it is redondant with some <tt>HEPMDB</tt> function.

This document is organised as follows: entries concerning similar or close information are gathered together. Each subsection is a parameter name. Sometimes only the main parameter is in the subsection title but the other subparameters are described in the same subsection.

__TOC__

== Model information ==
=== Model ===
This line corresponds to the model used. When using <tt>HEPMDB</tt>, each batch file is associated with a specific model. As a consequence, the default value of this line should not be changed.

=== Gauge ===
<tt>CalcHEP</tt> is able to use two different gauges for computation: Feynman gauge and unitary gauge. Some models require a specific gauge. We recommand leaving the default value for this.

=== Model changed ===
Each time the batch interface is run, it checks initially whether or not the subprocess numerical code exists. If it does, <tt>CalcHEP</tt> reuses the code and skips the often long process of code generation. If the code does not already exist, the numerical code is then generated and added to the library. If the model changed, the numerical codes are regenerated as appropriate.

== Process description ==
=== Process ===
Using the <tt>process</tt> keyword, it is possible to specify which process to compute. Multiple processes can be required.
The general syntax is:
<center><tt>Process: P1 [,P2] -> P3, P4 [,P5...]</tt></center>
This is in the form:
Incoming particles <tt>-></tt> outgoing particles. Particles can be particles from the model you are using or composite particles. It is recommended that the number of outgoing particles does not exceed 6.

=== Decay ===
It is possible to specify decays for the outgoing particles. Each decay will be written as follow:
<center><tt>Decay: P -> P1, P2 [,P3...]</tt></center>
Decays will automatically be connected to outgoing particles if possible. Decays will even be connected with one another.

Important note: make sure the same decay does not appear twice.

=== Composite ===
When specifying processes and decays, you can use composite particles, ''i.e.'' labels that refer to various possible particles. This is particularly useful when colliding protons or when studying jets.

The syntax is:
<center><tt>Composite: label=P1 [,P2...]</tt></center>

=== Remove ===
Sometimes, only specific processes will be of interest. It is possible to tell <tt>CalcHEP</tt> which particle you do not want as virtual particles in the processes.
The syntax is:
<center><tt>Remove: P1 [,P2...]</tt></center>

== Beam description ==
=== pdf1/pdf2 ===
=== p1/p2 ===
These two parameters define the energies of the beams. When using pdf, it can also be used as an input parameter for the pdf.
For instance, when using proton photon, this would corresponds to the energy of the initial proton.

== Model parameters ==
=== Parameter ===
It is possible to change some parameters of a model using <tt>Parameter</tt> keyword. The parameters are model specific.
Here is an example for selecting the elementary charge in the standard model:
<center><tt>Parameter: EE=0.31</tt></center>

=== Run parameter ===
It is usual for a model to have some free parameters not completely fixed by experiment.
For that kind of situation, you have the possibility to run several times the same computation with a different value for a specific parameter.

In order to use this possibility, you have to write four consecutive lines.
The first one specifies which parameter to study. To study the Higgs mass using the standard model, you would write:
<center><tt>Run parameter: Mh</tt></center>
Then you must specify the initial value and the increase of the value between each run:
<center><tt>Run begin: 100</tt></center>
<center><tt>Run step size: 10</tt></center>
Finally, the number of steps is defined by:
<center><tt>Run n steps: 6</tt></center>
So, with these specific lines, you will get 6 runs using the following value for the Higgs mass: 100, 110, 120, 130, 140, 150.

It is possible to mark several parameters for running. But it is only possible to explore hyperrectangle in the parameter space.

== QCD parameters ==
=== alpha Q ===

== Cuts ==
=== Cut parameter ===
=== Cut invert ===
=== Cut min/max ===

== Kinematics and regularization ==
=== Kinematics ===

In this part of the batch file the user needs to specify which kinematics are needed. The numbers in the kinematics refer to the particles in the process in order. For example, 12 relates to the first and second particles in the process. Here is an example of some kinematics:
<center><tt>Kinematics : 12 -> 34, 56</tt></center>
<center><tt>Kinematics : 34 -> 3 , 4</tt></center>
<center><tt>Kinematics : 56 -> 5 , 6</tt></center>

=== Regularization momentum ===

Applying regularization means that the phase space is adjusted so that resonances are properly accounted for. Applying regularization will mean that the result is far more accurate.

There are four lines needed in the batch file for each resonance. They are:
<center><tt>Regularization momentum: </tt></center>
<center><tt>Regularization mass: </tt></center>
<center><tt>Regularization width: </tt></center>
<center><tt>Regularization power: </tt></center>

== Events ==
=== Number of events (per run step) ===

This is totally up to the user and what he/she wishes to calculate. Please not that this number of events are being created for each run step. If events are not needed at all, please set this to 0.

=== Filename ===

This is self-explanatory.

== Parallelization ==
=== Parallelization method ===
=== Max number of cpus ===

The maximum number of cpus depends on the computer/cluster you are about to run this batch file on. Typically, this value is 4, 8 or 12.

=== sleep time ===
=== nice level ===

== Vegas session ==
=== nSess_1/2 ===

Normally, 5 should suffice.

=== nCalls_1/2 ===

A typical value would be 100,000.

CalcHEP tutorial

2013-08-23T08:53:15Z

Jblamey: /* Vegas session */

In order to familiarise yourself with <tt>CalcHEP</tt>, we will study two examples, one sightly more complicated than the other. Hopefully, by the end of this tutorial, you will be able to use majority of the functions of <tt>CalcHEP</tt>.

Please note that this is not a reference manual. If you wish to look at the reference manual, it is available [[CalcHEP reference|here]].

__TOC__

== A simple leptonic process ==
Let's start with a simple process and try to compute the matrix elements using <tt>CalcHEP</tt>. In this section, we will study:
<center><tt>ee → μμττ</tt></center>

The process will be studied in the standard model framework.

=== Preparing <tt>HEPMDB</tt> ===
First, connect to <tt>HEPMDB</tt> and go in the <tt>Calculate</tt> section. In the left panel, in the <tt>CalcHEP</tt> section, check whether the <tt>Standard Model (CKM=1)</tt> line appears. If not, in the <tt>CalcHEP</tt> menu, choose <tt>Import model</tt>. When you find the line <tt>Standard Model (CKM=1)</tt> for <tt>CalcHEP</tt> (it should be the model 43), select it and click <tt>Select</tt>. The model should now be accessible in your environment.

This model is the complete standard model without CKM matrix. As a consequence, it is lighter and in situation where quarks' flavours don't matter, it gives the same results as the standard model.

=== A template batch file ===
Select the model and select <tt>Edit Full Batch File</tt> in the <tt>CalcHEP</tt> menu. A new window will appear. You will be able to edit the batch file which is the file describing the process of interest. Click on the button <tt>Load batch template</tt>.

You now have a template file with nearly every possible field already offered. You also have help in the comments. The comments are lines beginning with a #. They are ignored by <tt>CalcHEP</tt> and thanks to them, you can add any information you want for any body reading the batch file.

=== Model information ===
The first three fields are information about the model.
# The first line gives the model to use. You should not touch it as this is a relic of <tt>CalcHEP</tt> local batch mode.
# The second option is <tt>Model changed</tt>. This tells <tt>CalcHEP</tt> that model files have been changed.
# Finally, <tt>Gauge</tt> tells what gauge to use, Feynmann or unitary. Many model are built implicitly assuming that the gauge is Feynmann's. So you should not change this field either.

=== Defining the process ===
We have several lines to define our process. Remove every <tt>Process</tt>, <tt>Decay</tt> and <tt>Composite</tt> field. You can now write:
<center><tt>Process: e,E -> m,M,l,L</tt></center>

In the standard model of <tt>CalcHEP</tt>, <tt>e</tt> refers to electron, <tt>m</tt> to muons, <tt>l</tt> to taus and the capital letters to their anti-particle. The particle list with their names for the model is available at the <tt>View particles</tt> entry of the <tt>CalcHEP</tt> menu. You cannot access it while editing the batch file however.

So we set up an electron-positron scattering with a pair of muons and a pair of taus outgoing.
No further information is needed to describe the process itself.

=== Beams configuration ===
We now have to configure the beams. The next field is about the pdfs. While this is useful for proton or any composite particle scattering, we do not need it for electron-positron scattering. We can write:
<center><tt>pdf1: OFF</tt></center>
And the same thing for the second pdf.

Concerning the energy of the beam, let's set 100 GeV beams.
<center><tt>p1: 100</tt></center>
<center><tt>p2: 100</tt></center>

=== Changing model parameters ===
We now have the possibility to change some model parameters. Let's say you want to change the strength of the electromagnetic force. You would write:
<center><tt>Parameter: EE=0.31</tt></center>
with <tt>0.31</tt> being the new value of the electrical charge of the electron in natural units.
Some models are more flexible than others on that kind of point. But for our tutorial, we are not going to change the well known parameters.

Instead, we're going to scan the possible Higgs masses. For this, you can write:
<center><tt>Run parameter: Mh</tt></center>
<center><tt>Run begin: 100</tt></center>
<center><tt>Run step size: 10</tt></center>
<center><tt>Run n steps: 6</tt></center>
This means we're going to scan the following values for <tt>Mh</tt>: 100 Gev, 110 GeV, 120 GeV, 130 GeV, 140 GeV, 150 GeV.
This is of course a pretty useful possibility when studying a new model.

We then have the possibility to set some parameters about QCD but this will be studied in the next example.

=== Cuts ===
Various cuts are possible. For our simple tutorial, we are not going to study them. Please refer to the reference manual if you are interested in them.

=== Kinematics and regularization ===
To tell <tt>CalcHEP</tt> how to handle the phase space, you should fill the kinematic information.
Using this information, a nice parametrisation of the phase space is used.

In our case, the two ingoing particles will give two bosons, each of them decaying in a lepton pair. Hence, our kinematics are written as:
<center><tt>Kinematics : 12 -> 34, 56</tt></center>
<center><tt>Kinematics : 34 -> 3 , 4</tt></center>
<center><tt>Kinematics : 56 -> 5 , 6</tt></center>

To improve the precision of the computation, it is important to tell <tt>CalcHEP</tt> where the resonances are.
In our case, we have resonance on the dimuon and ditau masses for the Z boson and for the Higgs.
So we will write:
<center><tt>Regularization momentum: 34</tt></center>
<center><tt>Regularization mass: MZ</tt></center>
<center><tt>Regularization width: wZ</tt></center>
<center><tt>Regularization power: 2</tt></center>

<center><tt>Regularization momentum: 34</tt></center>
<center><tt>Regularization mass: Mh</tt></center>
<center><tt>Regularization width: wh</tt></center>
<center><tt>Regularization power: 2</tt></center>

<center><tt>Regularization momentum: 56</tt></center>
<center><tt>Regularization mass: MZ</tt></center>
<center><tt>Regularization width: wZ</tt></center>
<center><tt>Regularization power: 2</tt></center>

<center><tt>Regularization momentum: 56</tt></center>
<center><tt>Regularization mass: Mh</tt></center>
<center><tt>Regularization width: wh</tt></center>
<center><tt>Regularization power: 2</tt></center>

=== Plots ===
<tt>CalcHEP</tt> has automated plot capacities. However, with <tt>HEPMDB</tt>, they are of little use. We will ignore them.

=== Event generation ===
For event generation, we really have two main parameters:
#The number of events. We'll write: <tt>Number of events (per run step): 100000</tt>
#The output file name. <tt>Filename: tutorial_ee_mmll</tt>

=== Parallelization ===
When using the template file of <tt>HEPMDB</tt>, all parallelization parameters are good. It is possible though, to set the maximum number of CPU to 24.

=== Vegas session ===
Finally, the Vegas session has some parameters. It will be used to compute the cross-section and to prepare the grid for event generation. Two sessions with 5 calls of 100,000 points is usually sufficient. With the number of calls there is a trade-off; the higher the number of calls means it will take longer to run the batch file on HEPMDB but reducing the number of calls leads to a decrease in accuracy of the cross sections. It is therefore worth experimenting with a couple of points in the batch interface of CalcHEP to see what optimization can be made.
<center><tt>nSess_1: 5</tt></center>
<center><tt>nCalls_1: 100000</tt></center>
<center><tt>nSess_2: 5</tt></center>
<center><tt>nCalls_2: 100000</tt></center>

=== Final words ===
The batch file is now complete and ready to run. I recommend plotting the number of events as a function of the tau pair invariant mass.

== Involving partons ==

CalcHEP tutorial

2013-08-23T08:52:36Z

Jblamey: /* Vegas session */

In order to familiarise yourself with <tt>CalcHEP</tt>, we will study two examples, one sightly more complicated than the other. Hopefully, by the end of this tutorial, you will be able to use majority of the functions of <tt>CalcHEP</tt>.

Please note that this is not a reference manual. If you wish to look at the reference manual, it is available [[CalcHEP reference|here]].

__TOC__

== A simple leptonic process ==
Let's start with a simple process and try to compute the matrix elements using <tt>CalcHEP</tt>. In this section, we will study:
<center><tt>ee → μμττ</tt></center>

The process will be studied in the standard model framework.

=== Preparing <tt>HEPMDB</tt> ===
First, connect to <tt>HEPMDB</tt> and go in the <tt>Calculate</tt> section. In the left panel, in the <tt>CalcHEP</tt> section, check whether the <tt>Standard Model (CKM=1)</tt> line appears. If not, in the <tt>CalcHEP</tt> menu, choose <tt>Import model</tt>. When you find the line <tt>Standard Model (CKM=1)</tt> for <tt>CalcHEP</tt> (it should be the model 43), select it and click <tt>Select</tt>. The model should now be accessible in your environment.

This model is the complete standard model without CKM matrix. As a consequence, it is lighter and in situation where quarks' flavours don't matter, it gives the same results as the standard model.

=== A template batch file ===
Select the model and select <tt>Edit Full Batch File</tt> in the <tt>CalcHEP</tt> menu. A new window will appear. You will be able to edit the batch file which is the file describing the process of interest. Click on the button <tt>Load batch template</tt>.

You now have a template file with nearly every possible field already offered. You also have help in the comments. The comments are lines beginning with a #. They are ignored by <tt>CalcHEP</tt> and thanks to them, you can add any information you want for any body reading the batch file.

=== Model information ===
The first three fields are information about the model.
# The first line gives the model to use. You should not touch it as this is a relic of <tt>CalcHEP</tt> local batch mode.
# The second option is <tt>Model changed</tt>. This tells <tt>CalcHEP</tt> that model files have been changed.
# Finally, <tt>Gauge</tt> tells what gauge to use, Feynmann or unitary. Many model are built implicitly assuming that the gauge is Feynmann's. So you should not change this field either.

=== Defining the process ===
We have several lines to define our process. Remove every <tt>Process</tt>, <tt>Decay</tt> and <tt>Composite</tt> field. You can now write:
<center><tt>Process: e,E -> m,M,l,L</tt></center>

In the standard model of <tt>CalcHEP</tt>, <tt>e</tt> refers to electron, <tt>m</tt> to muons, <tt>l</tt> to taus and the capital letters to their anti-particle. The particle list with their names for the model is available at the <tt>View particles</tt> entry of the <tt>CalcHEP</tt> menu. You cannot access it while editing the batch file however.

So we set up an electron-positron scattering with a pair of muons and a pair of taus outgoing.
No further information is needed to describe the process itself.

=== Beams configuration ===
We now have to configure the beams. The next field is about the pdfs. While this is useful for proton or any composite particle scattering, we do not need it for electron-positron scattering. We can write:
<center><tt>pdf1: OFF</tt></center>
And the same thing for the second pdf.

Concerning the energy of the beam, let's set 100 GeV beams.
<center><tt>p1: 100</tt></center>
<center><tt>p2: 100</tt></center>

=== Changing model parameters ===
We now have the possibility to change some model parameters. Let's say you want to change the strength of the electromagnetic force. You would write:
<center><tt>Parameter: EE=0.31</tt></center>
with <tt>0.31</tt> being the new value of the electrical charge of the electron in natural units.
Some models are more flexible than others on that kind of point. But for our tutorial, we are not going to change the well known parameters.

Instead, we're going to scan the possible Higgs masses. For this, you can write:
<center><tt>Run parameter: Mh</tt></center>
<center><tt>Run begin: 100</tt></center>
<center><tt>Run step size: 10</tt></center>
<center><tt>Run n steps: 6</tt></center>
This means we're going to scan the following values for <tt>Mh</tt>: 100 Gev, 110 GeV, 120 GeV, 130 GeV, 140 GeV, 150 GeV.
This is of course a pretty useful possibility when studying a new model.

We then have the possibility to set some parameters about QCD but this will be studied in the next example.

=== Cuts ===
Various cuts are possible. For our simple tutorial, we are not going to study them. Please refer to the reference manual if you are interested in them.

=== Kinematics and regularization ===
To tell <tt>CalcHEP</tt> how to handle the phase space, you should fill the kinematic information.
Using this information, a nice parametrisation of the phase space is used.

In our case, the two ingoing particles will give two bosons, each of them decaying in a lepton pair. Hence, our kinematics are written as:
<center><tt>Kinematics : 12 -> 34, 56</tt></center>
<center><tt>Kinematics : 34 -> 3 , 4</tt></center>
<center><tt>Kinematics : 56 -> 5 , 6</tt></center>

To improve the precision of the computation, it is important to tell <tt>CalcHEP</tt> where the resonances are.
In our case, we have resonance on the dimuon and ditau masses for the Z boson and for the Higgs.
So we will write:
<center><tt>Regularization momentum: 34</tt></center>
<center><tt>Regularization mass: MZ</tt></center>
<center><tt>Regularization width: wZ</tt></center>
<center><tt>Regularization power: 2</tt></center>

<center><tt>Regularization momentum: 34</tt></center>
<center><tt>Regularization mass: Mh</tt></center>
<center><tt>Regularization width: wh</tt></center>
<center><tt>Regularization power: 2</tt></center>

<center><tt>Regularization momentum: 56</tt></center>
<center><tt>Regularization mass: MZ</tt></center>
<center><tt>Regularization width: wZ</tt></center>
<center><tt>Regularization power: 2</tt></center>

<center><tt>Regularization momentum: 56</tt></center>
<center><tt>Regularization mass: Mh</tt></center>
<center><tt>Regularization width: wh</tt></center>
<center><tt>Regularization power: 2</tt></center>

=== Plots ===
<tt>CalcHEP</tt> has automated plot capacities. However, with <tt>HEPMDB</tt>, they are of little use. We will ignore them.

=== Event generation ===
For event generation, we really have two main parameters:
#The number of events. We'll write: <tt>Number of events (per run step): 100000</tt>
#The output file name. <tt>Filename: tutorial_ee_mmll</tt>

=== Parallelization ===
When using the template file of <tt>HEPMDB</tt>, all parallelization parameters are good. It is possible though, to set the maximum number of CPU to 24.

=== Vegas session ===
Finally, the Vegas session has some parameters. It will be used to compute the cross-section and to prepare the grid for event generation. Two sessions with 5 calls of 100,000 points is usually sufficient. With the number of calls there is a trade-off; the higher the number of calls means it will take longer to run the batch file on HEPMDB but reducing the number of calls can sometimes lead to a decrease in accuracy of the cross sections. It is therefore worth experimenting with a couple of points in the batch interface of CalcHEP to see what optimization can be made.
<center><tt>nSess_1: 5</tt></center>
<center><tt>nCalls_1: 100000</tt></center>
<center><tt>nSess_2: 5</tt></center>
<center><tt>nCalls_2: 100000</tt></center>

=== Final words ===
The batch file is now complete and ready to run. I recommend plotting the number of events as a function of the tau pair invariant mass.

== Involving partons ==

HEPMDB

2013-08-22T17:33:27Z

Jblamey:

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The High Energy Physics Model DataBase (HEPMDB) was created to facilitate the connection between high energy physics theory and experiment, to store and validate theoretical models, and to develop a dictionary of the model signatures which identifies the fundamental theories responsible for signals expected at the LHC.

HEPMDB is also designed to collect different signatures of its models and their respective experimental efficiencies. Using this information, HEPMDB will be able to compare its Beyond Standard Model (BSM) predictions with LHC data. In doing so, HEPMDB will be able to discriminate the underlying theory.

The database is in the development stage and your input in the 'Forum' section is highly appreciated. The database collects particle physics models. These models are supposed to be public and represent themselves as a set of Feynman Rules which can be expressed in the input form of any matrix element generator such as CalcHEP, CompHEP, FeynArts, Madgraph, SHERPA, WHIZARD. HEPMDB has an entrance for Model authors -- 'Authors' -- where Authors can test and validate their models.

To become an 'Author' you should register in the 'Register' section. 'Authors' are welcome to upload the LanHEP or FeynRules sources of their models.

If you are new here, you should start with the [[FAQ]].
</td>
<td width="550px" align="right">
[[File:Tt main.png|500px]]
[http://www.proofreading247.co.uk Proofreading]
</td>
</tr>
</table>

HEPMDB

2013-08-22T17:33:18Z

Jblamey:

<table width="100%" border="0">
<tr>
<td width="100%" valign="top">

The High Energy Physics Model DataBase (HEPMDB) was created to facilitate the connection between high energy physics theory and experiment, to store and validate theoretical models, and to develop a dictionary of the model signatures which identifies the fundamental theories responsible for signals expected at the LHC.

HEPMDB is also designed to collect different signatures of its models and their respective experimental efficiencies. Using this information, HEPMDB will be able to compare its Beyond Standard Model (BSM) predictions with LHC data. In doing so, HEPMDB will be able to discriminate the underlying theory.

The database is in the development stage and your input in the 'Forum' section is highly appreciated. The database collects particle physics models. These models are supposed to be public and represent themselves as a set of Feynman Rules which can be expressed in the input form of any matrix element generator such as CalcHEP, CompHEP, FeynArts, Madgraph, SHERPA, WHIZARD. HEPMDB has an entrance for Model authors -- 'Authors' -- where Authors can test and validate their models.

To become an 'Author' you should register in the 'Register' section. 'Authors' are welcome to upload the LanHEP or FeynRules sources of their models..

If you are new here, you should start with the [[FAQ]].
</td>
<td width="550px" align="right">
[[File:Tt main.png|500px]]
[http://www.proofreading247.co.uk Proofreading]
</td>
</tr>
</table>

HEPMDB

2013-08-22T17:32:54Z

Jblamey: