GSI Forum
GSI Helmholtzzentrum für Schwerionenforschung

Home » Hades » Pluto » [SOLVED] Beam Smear and Cross Sections
Re: Bear Smear and Cross Sections [message #13894 is a reply to message #13893] Tue, 28 August 2012 01:32 Go to previous messageGo to previous message
Michael Kunkel is currently offline  Michael Kunkel
Messages: 53
Registered: June 2011
continuous participant
From: *hr.hr.cox.net
I do understand that my thoughts are hard to convey, I appreciate the time you are taking with this. I wanted to clarify a typo in my previous message.

Instead of
Michael Kunkel wrote on Mon, 27 August 2012 21:07

Is _f the density function? If so, wouldn't using
Input : _x s cos(theta), _y is differential cross section
      Output : cross section
suffice?


I wanted to say

Is _f the density function? If so, wouldn't using
Input : _x s cos(theta), _y is differential cross section
      Output : _f cross section
suffice?

What I am finding hard to conceive here is how the distribution is generated.

Moreover, I want to clarify what I am trying to do, and hopefully I can understand my mistakes after this.

I have 64 models I will be using. I was assuming I could implement this as


  model1->SetRange(1.77,1.8); 
...
...
...
  model64->SetRange(2.56,2.6);

  model1->AddHistogram(example1,"value = Eval(_x); _f =_y * value");
  makeDistributionManager()->Add(model1);
  ...
  ...
  ...
  model64->AddHistogram(example64,"value = Eval(_x); _f =_y * value");
  makeDistributionManager()->Add(model64);


In the above snipet I use 1 histogram for each model. Each histogram is derived from published data with
_x = Cos(theta)
_y = Differential Cross section

The histograms are extrapolated from TGraphs (see below);
c.m. 1.77 ->1.8 GeV
index.php?t=getfile&id=7103&private=0

c.m. 2.56 ->2.6 GeV
index.php?t=getfile&id=7104&private=0

As it can be seen from the plots above, the cross section depends on both the c.m. energy and Cos(theta);

I am trying to model this, however the example macro you provided states (lines 31 & 32):
    //Input:  _x is cos(theta), _y is the c.m. energy
    //Output: _f: cross section

model->AddHistogram(distribution,"value = Eval(_x); _f = _y * value");

But cross section, from a physics stand point is proportional to Cos(theta) / s, where s is square of c.m. energy.

This is my a source of my confusion and also not understanding how to use what I already have, cos(theta) vs. diff XSection, is the other part of my confusion.

Thanks

[Updated on: Tue, 28 August 2012 01:34]

Report message to a moderator

 
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Previous Topic: New Pluto web page
Next Topic: [SOLVED] PAnyDistribution broke in v5.40.5
Goto Forum:
  


Current Time: Wed Nov 06 06:53:45 CET 2024

Total time taken to generate the page: 0.00991 seconds