# A Search for Neutrino Induced Coherent NC($\pi^{0}$) Production in the MINOS Near Detector

### Description

The production of single, highly forward {pi}{sup 0} mesons by NC coherent neutrino-nucleus interactions ({nu}{sub {mu}} + N {yields} {nu}{sub {mu}} + N + {pi}{sup 0}) is a process which probes fundamental aspects of the weak interaction. This reaction may also pose as a limiting background for long baseline searches for {nu}{sub {mu}} {yields} {nu}{sub e} oscillations if the neutrino mixing angle {theta}{sub 13} is very small. The high-statistics sample of neutrino interactions recorded by the MINOS Near Detector provides an opportunity to measure the cross section of this coherent reaction on a relatively large-A nucleus at an average E{sub ... continued below

263 pages

### Creation Information

Cherdack, Daniel David & U., /Tufts November 1, 2010.

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### Description

The production of single, highly forward {pi}{sup 0} mesons by NC coherent neutrino-nucleus interactions ({nu}{sub {mu}} + N {yields} {nu}{sub {mu}} + N + {pi}{sup 0}) is a process which probes fundamental aspects of the weak interaction. This reaction may also pose as a limiting background for long baseline searches for {nu}{sub {mu}} {yields} {nu}{sub e} oscillations if the neutrino mixing angle {theta}{sub 13} is very small. The high-statistics sample of neutrino interactions recorded by the MINOS Near Detector provides an opportunity to measure the cross section of this coherent reaction on a relatively large-A nucleus at an average E{sub {nu}} = 4.9 GeV. A major challenge for this measurement is the isolation of forward-going electromagnetic (EM) showers produced by the relatively rare coherent NC({pi}{sup 0}) process amidst an abundant rate of incoherently produced EM showers. The backgrounds arise from single {pi}{sup 0} dominated NC events and also from quasi-elastic-like CC scattering of electron neutrinos. In this Thesis the theory of coherent interactions is summarized, and previous measurements of the coherent NC({pi}{sup 0}) cross section are reviewed. Then, methods for selecting a sample of coherent NC({pi}{sup 0}) like events, extracting the coherent NC({pi}{sup 0}) event rate from that sample, estimating the analysis uncertainties, and calculating a cross section, are presented. A signal for neutrino-induced NC({pi}{sup 0}) production is observed in the relevant kinematic regime as an excess of events of three standard deviations above background. The reaction cross sections, averaged over an energy window of 2.5 {&lt;=} E{sub {nu}} {&lt;=} 9.0 GeV is determined to be (31.6{+-}10.5) x 10{sup -40} cm{sup 2}/nucleus. The result is the first evidence obtained for neutrino-nucleus coherent NC({pi}{sup 0}) scattering on iron, and is the first measurement on an average nuclear target above A = 30. The cross section measurement is in agreement with NEUGEN3 implementation of the model by Rein and Sehgal which is motived by the PCAC hypothesis.

263 pages

### Identifier

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• Report No.: FERMILAB-THESIS-2010-54
• Grant Number: AC02-07CH11359
• DOI: 10.2172/1001376 | External Link
• Office of Scientific & Technical Information Report Number: 1001376

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#### Office of Scientific & Technical Information Technical Reports

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### Creation Date

• November 1, 2010

### Added to The UNT Digital Library

• May 19, 2016, 3:16 p.m.

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• Dec. 1, 2016, 7 p.m.

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Cherdack, Daniel David & U., /Tufts. A Search for Neutrino Induced Coherent NC($\pi^{0}$) Production in the MINOS Near Detector, thesis or dissertation, November 1, 2010; Batavia, Illinois. (https://digital.library.unt.edu/ark:/67531/metadc839447/: accessed March 18, 2019), University of North Texas Libraries, Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.