search for z’-boson signal using neural networks a.n.buryk and v.v.skalozub

Search for Z’-boson signalusing neural networks

A.N.Buryk and V.V.Skalozub

Many theories predict Z’-boson existance.

There are many methods to search it.

But the lack of experimental statisticks doesn’t allow to find it.

Search for Z’-boson signal using neural networks A.N.Buryk and V.V.Skalozub

Starting point of this work was “Model-independent search for the Abelian Z’-boson in the Bha-Bha process”, made by A.V.Gulov and

V.V.Skalozub

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The Bha-Bha process was investigatedFor this process we have only one equation from the third formula:

The leading-order differential cross-section of the Bha-Bha process depends on next combinations of Z’-boson couplings:

Taking into account RG equations they are reduced to three parameters:

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z1 z2 dσ/dz error

189 … … … …

192 … … … …

… … … … …

207 … … … …

Common view of OPAL collaboration data

View of OPAL collaboration data after some preparations

z1 z2 Δ(dσ/dz) error

189 … … … …

192 … … … …

… … … … …

207 … … … …


On the diagram it looks like a band

1 2 3 4 5 6


Set of 2 neural networks was used.

Each network had its own discard criterion.

First criterion: discard that data, that correspond to very big v2

Second criterion: discard that data, for which RG equations are not applied

1 networkSignal: v2=0,0001 Antisignal: v2=0,01

2 network

Antisignal:

Signal: aY e2~

aY e30000~


Scheme of neural network structure


We used neural networks with 2 incoming neurons, 10 hidden neurons an 1 outgoing neurons.

After processing by first network we discard 2% of the width.After processing by the second network we discard 6,2% of bandwidth.

So, after all actions, the overall decrease is about 8,2%.

To construct and learn neural networks the MLPFit package was used.To use obtained neural networks to process the data, 2 programs were

written.


1. A.V.Gulov and V.V.Skalozub “Model-independent search for the Abelian Z’boson in the Bhabha process”, arXiv: hep-ph/0408076.

2. MLPFit, http://home.cern.ch/~schwind/MLPfit.html

Bibliographical links:

search for z’-boson signal using neural networks a.n.buryk and v.v.skalozub

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