Z'-boson mass prediction based on neural network s analysis of LEP2 data

Z'-boson mass predictionbased on neural networks

analysis of LEP2 data

A.N.Buryk and V.V.Skalozub

Many theories predict Z’-boson existance.

There are many methods to search for it.

But the lack of accessible nowadays experimental data doesn’t allow to find it.

Z'-boson mass prediction based on neural networks analysis of LEP2 data A.N.Buryk and V.V.Skalozub

Searching for Z' is one of the goals

of experiments at LHC

Z’-boson mass prediction is needed

with the highest accessible precision

Search for Z'-boson using neural networks within LEP2 data set A.N.Buryk and V.V.SkalozubZ'-boson mass prediction based on neural networks analysis of LEP2 data A.N.Buryk and V.V.Skalozub

Search for Z'-boson using neural networks within LEP2 data set A.N.Buryk and V.V.Skalozub

TeVmZ 2.17.0' One-parameter fit model-independent search

LEP2 data set

Model-dependent searchsearch at CDF II TeVmZ 923.0'

Z'-boson mass prediction based on neural networks analysis of LEP2 data A.N.Buryk and V.V.Skalozub

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

V.V.Skalozub

Search for Z'-boson using neural networks within LEP2 data set A.N.Buryk and V.V.SkalozubZ'-boson mass prediction based on neural networks analysis of LEP2 data A.N.Buryk and V.V.Skalozub

Search for Z'-boson using neural networks within LEP2 data set A.N.Buryk and V.V.Skalozub

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Z'-boson mass prediction based on neural networks analysis of LEP2 data A.N.Buryk and V.V.Skalozub

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

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

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

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Search for Z'-boson using neural networks within LEP2 data set A.N.Buryk and V.V.SkalozubZ'-boson mass prediction based on neural networks analysis of LEP2 data A.N.Buryk and V.V.Skalozub

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Z'-boson mass prediction based on neural networks analysis of LEP2 data A.N.Buryk and V.V.Skalozub

Neural network analysis

Neural network was trained to discard the data,Neural network was trained to discard the data,which are associated with a backgroundwhich are associated with a background

SignalSignal: the differential cross-section for the Bhabha process : the differential cross-section for the Bhabha process obtained within the SM, extended by the Z‘-bosonobtained within the SM, extended by the Z‘-boson

BackgroundBackground: the deviation from the signal by the: the deviation from the signal by thevalue, equals to the redoubled uncertainty of LEP2 value, equals to the redoubled uncertainty of LEP2

experimental dataexperimental data

Search for Z'-boson using neural networks within LEP2 data set A.N.Buryk and V.V.SkalozubZ'-boson mass prediction based on neural networks analysis of LEP2 data A.N.Buryk and V.V.Skalozub

Search for Z'-boson using neural networks within LEP2 data set A.N.Buryk and V.V.SkalozubZ'-boson mass prediction based on neural networks analysis of LEP2 data A.N.Buryk and V.V.Skalozub

Search for Z'-boson using neural networks within LEP2 data set A.N.Buryk and V.V.Skalozub

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

Training algorithm with back propagation of the error was used.After processing by the network we discard 20% of the uncertainty.

To construct and train neural networks the MLPFit package was used.

To process the data with obtained neural networks necessary programs were written.

L3 183-189 GeV OPAL 130-207 GeVALEPH 130-183 GeV DELPHI 189-207 GeV

Z'-boson mass prediction based on neural networks analysis of LEP2 data A.N.Buryk and V.V.Skalozub

Search for Z'-boson using neural networks within LEP2 data set A.N.Buryk and V.V.Skalozub

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Z'-boson mass prediction based on neural networks analysis of LEP2 data A.N.Buryk and V.V.Skalozub

Search for Z'-boson using neural networks within LEP2 data set A.N.Buryk and V.V.Skalozub

BEFOREAFTER

95% CL area for v2

Z'-boson mass prediction based on neural networks analysis of LEP2 data A.N.Buryk and V.V.Skalozub

Search for Z'-boson using neural networks within LEP2 data set A.N.Buryk and V.V.Skalozub

BEFOREAFTER

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Z'-boson mass prediction based on neural networks analysis of LEP2 data A.N.Buryk and V.V.Skalozub

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Z'-boson mass prediction based on neural networks analysis of LEP2 data A.N.Buryk and V.V.Skalozub

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One-parameter fit

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TeVmZ 05.153.0' Neural networktwo-parameter fit

One-parameter fit

Z'-boson mass prediction based on neural networks analysis of LEP2 data A.N.Buryk and V.V.Skalozub