Home » Hades » Pluto » [SOLVED] Beam Smear and Cross Sections
| Re: Bear Smear and Cross Sections [message #13895 is a reply to message #13894] |
Tue, 28 August 2012 08:35   |
Ingo Froehlich
Messages: 167
Registered: March 2004
Location: IKF - Frankfurt
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first-grade participant |
From: *dip.t-dialin.net
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| Michael Kunkel wrote on Tue, 28 August 2012 01:32 |
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
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No, that's not correct. _x is cos(theta), and _y is the c.m. energy. It's a 2-dimensional function. _f is the results, and this is (dsigma/d(cos(theta)))(q), i.e. the differential cross section as a function of cos(theta) and q
| Michael Kunkel wrote on Tue, 28 August 2012 01:32 |
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);
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No, this will not work. Pluto is a sampling event generator. If you use it like this, the first model samples theta and q, the second model overwrites that, and so on...
| Michael Kunkel wrote on Tue, 28 August 2012 01:32 |
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
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You are using a different convention, this is part of the confusion. _y is the c.m. energy in a 2-dimensional function. If you are using a 1-dimensional histogram, the results should be still mapped on _f, not _y.
The only thing you have to implement is a function _f = F(_x,_y) = F(cos(theta),q)
--
Ingo Froehlich
IKF - University of Frankfurt
069-798-47027, FAX: -47024
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