Observation of Electron Antineutrino Disappearance by the Daya Bay Reactor Neutrino Experiment

Observation of Electron Antineutrino Disappearance by the Daya Bay Reactor Neutrino Experiment PDF Author:
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Languages : en
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Observation of Electron Antineutrino Disappearance by the Daya Bay Reactor Neutrino Experiment

Observation of Electron Antineutrino Disappearance by the Daya Bay Reactor Neutrino Experiment PDF Author:
Publisher:
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Languages : en
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Observation of Antineutrino Disappearance at the Daya Bay Experiment

Observation of Antineutrino Disappearance at the Daya Bay Experiment PDF Author:
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Languages : en
Pages : 0

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Many experiments in the last few decades have demonstrated the neutrino's ability to change flavor while traveling through space and time, or oscillate. One of the last remaining unknown parameters describing this oscillation, theta13, is crucial in defining the magnitude of CP-violation in the lepton sector and in examining the neutrino's role in the universe's matter-antimatter asymmetry. The Daya Bay experiment has measured theta13 with unprecedented precision by observing disappearance of reactor antineutrinos with identical detectors at multiple distances. This thesis will introduce the Daya Bay experiment, describe the design, construction, characterization, and calibration of its functionally identical antineutrino detectors, and present an independent relative rate analysis of the first Daya Bay data. With roughly two months of data, this analysis has conclusively measured this mixing parameter, excluding the theta13=0 hypothesis to five standard deviations. Proper understanding of this measurement's detector systematics are demonstrated with a side-by-side comparison of near-site detector data, which shows identical antineutrino detection rates between detectors. The implications of this non-zero theta13 measurement are discussed, as well as possible further contributions of the Daya Bay experiment to neutrino physics knowledge.

New Measurement of Antineutrino Oscillation with the Full Detector Configuration at Daya Bay

New Measurement of Antineutrino Oscillation with the Full Detector Configuration at Daya Bay PDF Author:
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Languages : en
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We report a new measurement of electron antineutrino disappearance using the fully constructed Daya Bay Reactor Neutrino Experiment. The final two of eight antineutrino detectors were installed in the summer of 2012. Including the 404 days of data collected from October 2012 to November 2013 resulted in a total exposure of 6.9×105 GWth ton days, a 3.6 times increase over our previous results. Improvements in energy calibration limited variations between detectors to 0.2%. Removal of six 241Am- 13C radioactive calibration sources reduced the background by a factor of 2 for the detectors in the experimental hall furthest from the reactors. Direct prediction of the antineutrino signal in the far detectors based on the measurements in the near detectors explicitly minimized the dependence of the measurement on models of reactor antineutrino emission. The uncertainties in our estimates of 2sin2[theta]13 and.

Observation of ν_μ→ν_e Oscillation in the T2K Experiment

Observation of ν_μ→ν_e Oscillation in the T2K Experiment PDF Author: Kei Ieki
Publisher: Springer
ISBN: 4431558373
Category : Science
Languages : en
Pages : 205

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In this thesis the author contributes to the analysis of neutrino beam data collected between 2010 and 2013 to identify νμ→νe events at the Super-Kamiokande detector. In particular, the author improves the pion–nucleus interaction uncertainty, which is one of the dominant systematic error sources in T2K neutrino oscillation measurement. In the thesis, the measurement of νμ→νe oscillation in the T2K (Tokai to Kamioka) experiment is presented and a new constraint on δCP is obtained. This measurement and the analysis establish, at greater than 5σ significance, the observation of νμ→νe oscillation for the first time in the world. Combining the T2K νμ→νe oscillation measurement with the latest findings on oscillation parameters including the world average value of θ13 from reactor experiments, the constraint on the value of δCP at the 90% confidence level is obtained. This constraint on δCP is an important step towards the discovery of CP violation in the lepton sector.

Observation of Antineutrino Oscillations from Spectral Distortions at the Daya Bay Reactor Neutrino Experiment

Observation of Antineutrino Oscillations from Spectral Distortions at the Daya Bay Reactor Neutrino Experiment PDF Author:
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Category :
Languages : en
Pages : 0

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Neutrino oscillation is the quantum mechanical phenomenon whereby neutrinos or antineutrinos can spontaneously transform from one of three flavors0́4 electron, muon, or tau0́4 to another. The Daya Bay Reactor Neutrino Experiment has measured neutrino mixing angle Ø13, for the first time, to world-leading precision. The analysis in this dissertation reports sin22Ø13 = 0.088 0.0088, m232 = 2.54+0:172:54+0:17-0.18 *108́ eV2 and m231 = 2.62 108́23 eV2, assuming m221 = 7.50*108-5 eV2 and normal hierarchy. These measurements were accomplished by the early deployment of six functionally identical detectors to observe antineutrino flux from six nuclear reactors, between 2 to 12 MeV. Half the detectors are sited near the position of maximal oscillation, about 1600m from the reactors, while the rest are located 500m and 550m away at two sites, where the oscillation probability is low. The relative comparison of antineutrino rates and energies at identical near and far detectors provides a direct measurement of Ø13 and m2, while greatly reducing systematic uncertainties. The chapters that follow explain neutrino oscillations, and experiment strategy and construction. My contributions to the experiment are highlighted in more detail in the introductions to chapters 3 through 9. These include a detector camera monitoring system, a sensitivity calculation that helped motivate the early six-detector analysis, and the measurements of oscillation parameters from antineutrino rates and spectra.

First Direct Observation of Muon Antineutrino Disappearance

First Direct Observation of Muon Antineutrino Disappearance PDF Author:
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Languages : en
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This letter reports the first direct observation of muon antineutrino disappearance. The MINOS experiment has taken data with an accelerator beam optimized for ????????? production, accumulating an exposure of 1.71 x 1020 protons on target. In the Far Detector, 97 charged current ????????? events are observed. The no-oscillation hypothesis predicts 156 events and is excluded at 6.3?. The best fit to oscillation yields.

First Measurement of the Muon Anti-Neutrino Charged Current Quasielastic Double-Differential Cross Section

First Measurement of the Muon Anti-Neutrino Charged Current Quasielastic Double-Differential Cross Section PDF Author: Joseph Grange
Publisher: Springer
ISBN: 3319095730
Category : Science
Languages : en
Pages : 185

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Book Description
This book presents a major step forward in experimentally understanding the behavior of muon neutrinos and antineutrinos. Apart from providing the world’s first measurement of these interactions in a mostly unexplored energy region, the data presented advances the neutrino community’s preparedness to search for an asymmetry between matter and anti-matter that may very well provide the physical mechanism for the existence of our universe. The details of these measurements are preceded by brief summaries of the history of the neutrino, the phenomenon of neutrino oscillations, and a description of their interactions. Also provided are details of the experimental setup for the measurements and the muon antineutrino cross-section measurement which motivates the need for dedicated in situ background constraints. The world’s first measurement of the neutrino component of an antineutrino beam using a non-magnetized detector, as well as other crucial background constraints, are also presented in the book. By exploiting correlated systematic uncertainties, combined measurements of the muon neutrino and antineutrino cross sections described in the book maximize the precision of the extracted information from both results.

State Of The Art Of Neutrino Physics, The: A Tutorial For Graduate Students And Young Researchers

State Of The Art Of Neutrino Physics, The: A Tutorial For Graduate Students And Young Researchers PDF Author: Antonio Ereditato
Publisher: World Scientific
ISBN: 9813226102
Category : Science
Languages : en
Pages : 580

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Book Description
The neutrino is the most fascinating elementary particle due to its elusive nature and outstanding properties that have attracted the interest of generations of physicists since 1930, when it was first postulated by Wolfgang Pauli as a 'desperate remedy' to explain the apparent energy violation in the beta decay. Many fundamental discoveries in particle physics had the neutrino involved in one way or another. To date, neutrino physics is still one of the hottest topics of modern particle physics. Key experiments and significant theoretical developments have contributed in building up what we can call now the Standard Model of Neutrino Physics.The aim of the book is to provide graduate students and young researchers a comprehensive tutorial in modern neutrino physics, specially tailored with emphasis on the educational aspects. It provides an overview of the basics and of recent achievements in the field, from both experimental and theoretical points of view.

The B−L Phase Transition

The B−L Phase Transition PDF Author: Kai Schmitz
Publisher: Springer Science & Business Media
ISBN: 331900963X
Category : Science
Languages : en
Pages : 225

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Book Description
Several of the very foundations of the cosmological standard model — the baryon asymmetry of the universe, dark matter, and the origin of the hot big bang itself — still call for an explanation from the perspective of fundamental physics. This work advocates one intriguing possibility for a consistent cosmology that fills in the theoretical gaps while being fully in accordance with the observational data. At very high energies, the universe might have been in a false vacuum state that preserved B-L, the difference between the baryon number B and the lepton number L as a local symmetry. In this state, the universe experienced a stage of hybrid inflation that only ended when the false vacuum became unstable and decayed, in the course of a waterfall transition, into a phase with spontaneously broken B-L symmetry. This B-L Phase Transition was accompanied by tachyonic preheating that transferred almost the entire energy of the false vacuum into a gas of B-L Higgs bosons, which in turn decayed into heavy Majorana neutrinos. Eventually, these neutrinos decayed into massless radiation, thereby producing the entropy of the hot big bang, generating the baryon asymmetry of the universe via the leptogenesis mechanism and setting the stage for the production of dark matter. Next to a variety of conceptual novelties and phenomenological predictions, the main achievement of the thesis is hence the fascinating notion that the leading role in the first act of our universe might have actually been played by neutrinos.

Introduction to the Physics of Massive and Mixed Neutrinos

Introduction to the Physics of Massive and Mixed Neutrinos PDF Author: Samoil Bilenky
Publisher: Springer
ISBN: 3319748025
Category : Science
Languages : en
Pages : 283

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Book Description
Small neutrino masses are the first signs of new physics beyond the Standard Model of particle physics. Since the first edition of this textbook appeared in 2010, the Nobel Prize has been awarded "for the discovery of neutrino oscillations, which shows that neutrinos have mass". The measurement of the small neutrino mixing angle $\theta_{13}$ in 2012, launched the precision stage of the investigation of neutrino oscillations. This measurement now allows such fundamental problems as the three-neutrino mass spectrum - is it normal or inverted? – and the $CP$ violation in the lepton sector to be tackled. In order to understand the origin of small neutrino masses, it remains crucial to reveal the nature of neutrinos with definite masses: are they Dirac neutrinos possessing a conserved lepton number, which distinguishes neutrinos and antineutrinos, or are they Majorana neutrinos with identical neutrinos and antineutrinos? Experiments searching for the neutrinoless double beta decay are presently under way to answer this fundamental question. The second edition of this book comprehensively discusses all these important recent developments. Based on numerous lectures given by the author, a pioneer of modern neutrino physics (recipient of the Bruno Pontecorvo Prize 2002), at different institutions and schools, it offers a gentle yet detailed introduction to the physics of massive and mixed neutrinos that prepares graduate students and young researchers entering the field for the exciting years ahead in neutrino physics.