Sterile Neutrinos in Cold Climates

Sterile Neutrinos in Cold Climates PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 339

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Book Description
Measurements of neutrino oscillations at short baselines contain an intriguing set of experimental anomalies that may be suggestive of new physics such as the existence of sterile neutrinos. This three-part thesis presents research directed towards understanding these anomalies and searching for sterile neutrino oscillations. Part I contains a theoretical discussion of neutrino coherence properties. The open-quantum-system picture of neutrino beams, which allows a rigorous prediction of coherence distances for accelerator neutrinos, is presented. Validity of the standard treatment of active and sterile neutrino oscillations at short baselines is verified and non-standard coherence loss effects at longer baselines are predicted. Part II concerns liquid argon detector development for the MicroBooNE experiment, which will search for short-baseline oscillations in the Booster Neutrino Beam at Fermilab. Topics include characterization and installation of the MicroBooNE optical system; test-stand measurements of liquid argon optical properties with dissolved impurities; optimization of wavelength-shifting coatings for liquid argon scintillation light detection; testing and deployment of high-voltage surge arrestors to protect TPC field cages; and software development for optical and TPC simulation and reconstruction. Part III presents a search for sterile neutrinos using the IceCube neutrino telescope, which has collected a large sample of atmospheric-neutrino-induced events in the 1-10 TeV energy range. Sterile neutrinos would modify the detected neutrino flux shape via MSW-resonant oscillations. Following a careful treatment of systematic uncertainties in the sample, no evidence for MSW-resonant oscillations is observed, and exclusion limits on 3+1 model parameter space are derived. Under the mixing assumptions made, the 90% confidence level exclusion limit extends to sin22[theta]24d"0.02 at m2 ~ 0.3 eV 2, and the LSND and MiniBooNE allowed regions are excluded at>99% confidence level.

Sterile Neutrinos in Cold Climates

Sterile Neutrinos in Cold Climates PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 339

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Book Description
Measurements of neutrino oscillations at short baselines contain an intriguing set of experimental anomalies that may be suggestive of new physics such as the existence of sterile neutrinos. This three-part thesis presents research directed towards understanding these anomalies and searching for sterile neutrino oscillations. Part I contains a theoretical discussion of neutrino coherence properties. The open-quantum-system picture of neutrino beams, which allows a rigorous prediction of coherence distances for accelerator neutrinos, is presented. Validity of the standard treatment of active and sterile neutrino oscillations at short baselines is verified and non-standard coherence loss effects at longer baselines are predicted. Part II concerns liquid argon detector development for the MicroBooNE experiment, which will search for short-baseline oscillations in the Booster Neutrino Beam at Fermilab. Topics include characterization and installation of the MicroBooNE optical system; test-stand measurements of liquid argon optical properties with dissolved impurities; optimization of wavelength-shifting coatings for liquid argon scintillation light detection; testing and deployment of high-voltage surge arrestors to protect TPC field cages; and software development for optical and TPC simulation and reconstruction. Part III presents a search for sterile neutrinos using the IceCube neutrino telescope, which has collected a large sample of atmospheric-neutrino-induced events in the 1-10 TeV energy range. Sterile neutrinos would modify the detected neutrino flux shape via MSW-resonant oscillations. Following a careful treatment of systematic uncertainties in the sample, no evidence for MSW-resonant oscillations is observed, and exclusion limits on 3+1 model parameter space are derived. Under the mixing assumptions made, the 90% confidence level exclusion limit extends to sin22[theta]24d"0.02 at m2 ~ 0.3 eV 2, and the LSND and MiniBooNE allowed regions are excluded at>99% confidence level.

Sterile Neutrinos in Cold Climates

Sterile Neutrinos in Cold Climates PDF Author: Benjamin J. P. Jones
Publisher:
ISBN:
Category :
Languages : en
Pages : 339

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Book Description
Measurements of neutrino oscillations at short baselines contain an intriguing set of experimental anomalies that may be suggestive of new physics such as the existence of sterile neutrinos. This three-part thesis presents research directed towards understanding these anomalies and searching for sterile neutrino oscillations. Part I contains a theoretical discussion of neutrino coherence properties. The open-quantum-system picture of neutrino beams, which allows a rigorous prediction of coherence distances for accelerator neutrinos, is presented. Validity of the standard treatment of active and sterile neutrino oscillations at short baselines is verified and non-standard coherence loss effects at longer baselines are predicted. Part II concerns liquid argon detector development for the MicroBooNE experiment, which will search for short-baseline oscillations in the Booster Neutrino Beam at Fermilab. Topics include characterization and installation of the MicroBooNE optical system; test-stand measurements of liquid argon optical properties with dissolved impurities; optimization of wavelength-shifting coatings for liquid argon scintillation light detection; testing and deployment of high-voltage surge arrestors to protect TPC field cages; and software development for optical and TPC simulation and reconstruction. Part III presents a search for sterile neutrinos using the IceCube neutrino telescope, which has collected a large sample of atmospheric-neutrino-induced events in the 1-10 TeV energy range. Sterile neutrinos would modify the detected neutrino flux shape via MSW-resonant oscillations. Following a careful treatment of systematic uncertainties in the sample, no evidence for MSW-resonant oscillations is observed, and exclusion limits on 3+1 model parameter space are derived. Under the mixing assumptions made, the 90% confidence level exclusion limit extends to ... , and the LSND and MiniBooNE allowed regions are excluded at >99% confidence level.

Search for Sterile Neutrinos with the MINOS Long-Baseline Experiment

Search for Sterile Neutrinos with the MINOS Long-Baseline Experiment PDF Author: Ashley Michael Timmons
Publisher: Springer
ISBN: 331963769X
Category : Science
Languages : en
Pages : 177

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Book Description
This thesis highlights data from MINOS, a long-baseline accelerator neutrino experiment, and details one of the most sensitive searches for the sterile neutrino ever made. Further, it presents a new analysis paradigm to enable this measurement and a comprehensive study of the myriad systematic uncertainties involved in a search for a few-percent effect, while also rigorously investigating the statistical interpretation of the findings in the context of a sterile neutrino model. Among the scientific community, this analysis was quickly recognized as a foundational measurement in light of which all previous evidence for the sterile neutrino must now be (re)interpreted. The existence of sterile neutrinos has long been one of the key questions in the field. Not only are they a central component in many theories of new physics, but a number of past experiments have yielded results consistent with their existence. Nonetheless, they remain controversial: the interpretation of the data showing evidence for these sterile neutrinos is hotly debated.

Probing Particle Physics With Neutrino Telescopes

Probing Particle Physics With Neutrino Telescopes PDF Author: Carlos Perez De Los Heros
Publisher: World Scientific
ISBN: 9813275030
Category : Science
Languages : en
Pages : 433

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Book Description
This book introduces the reader to how fundamental topics in particle physics can be studied with the largest neutrino telescopes currently in operation. Due to their large size, reaching cubic-kilometer volumes, and their wide energy response, these unusual detectors can provide insight on neutrino oscillations, dark matter searches or searches for exotic particles, new neutrino interactions or extra dimensions, among many other topics.Lacking a man-made neutrino 'beam', neutrino telescopes use the copious flux of neutrinos continuously produced by cosmic rays interacting in the Earth's atmosphere, as well as neutrinos from astrophysical origin. They have therefore access to neutrinos of higher energies and much longer baselines than those produced in present accelerators, being able to search for new physics at complementary scales than currently available in particle physics laboratories around the world.Written by carefully chosen experts in the field, the book introduces each topic in a pedagogical way apt not only to professionals, but also to students or the interested reader with a background in physics.

Sterile Neutrinos as Dark Matter

Sterile Neutrinos as Dark Matter PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 11

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Book Description
The simplest model that can accommodate a viable nonbaryonic dark matter candidate is the standard electroweak theory with the addition of right-handed or sterile neutrinos. This model has been studied extensively in the context of the hot dark matter scenario. We reexamine this model and find that hot, warm, and cold dark matter are all possibilities. We focus on the case where sterile neutrinos are the dark matter. Since their only direct coupling is to left-handed or active neutrinos, the most efficient production mechanism is via neutrino oscillations. If the production rate is always less than the expansion rate, then these neutrinos will never be in thermal equilibrium. However, they may still play a significant role in the dynamics of the Universe and possibly provide the missing mass necessary for closure. We consider a single generation of neutrino fields ([nu][sub L], [nu][sub R]) with a Dirac mass, [mu], and a Majorana mass for the right-handed components only, M. For M [much gt] [mu] we show that the number density of sterile neutrinos is proportional to [mu][sup 2]/M so that the energy density today is independent of M. However M is crucial in determining the large scale structure of the Universe. In particular, M [approx equal] 0.1--1.0 key leads to warm dark matter and a structure formation scenario that may have some advantages over both the standard hot and cold dark matter scenarios.

Sterile Neutrino Dark Matter

Sterile Neutrino Dark Matter PDF Author: Alexander Merle
Publisher: Morgan & Claypool Publishers
ISBN: 1681744813
Category : Science
Languages : en
Pages : 102

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Book Description
This book is a new look at one of the hottest topics in contemporary science, Dark Matter. It is the pioneering text dedicated to sterile neutrinos as candidate particles for Dark Matter, challenging some of the standard assumptions which may be true for some Dark Matter candidates but not for all. So, this can be seen either as an introduction to a specialized topic or an out-of-the-box introduction to the field of Dark Matter in general. No matter if you are a theoretical particle physicist, an observational astronomer, or a ground based experimentalist, no matter if you are a grad student or an active researcher, you can benefit from this text, for a simple reason: a non-standard candidate for Dark Matter can teach you a lot about what we truly know about our standard picture of how the Universe works.

The Search for Sterile Neutrinos with IceCube

The Search for Sterile Neutrinos with IceCube PDF Author: Kevin Ghorbani
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
IceCube is a kilometer-cubed neutrino detector located at the South Pole. IceCube is sensitive to sterile neutrinos in the range of the masses and mixing angles of the LSND/MiniBooNE anomaly ($\Delta m^2$

Light, Unstable Sterile Neutrinos

Light, Unstable Sterile Neutrinos PDF Author: Marjon H. Moulai
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
Longstanding anomalies in neutrino oscillation experiments point to the existence of a fourth, hypothetical neutrino: the sterile neutrino. Global fits to a sterile neutrino model find a strong preference for such a model over the massive neutrino Standard Model. However, the fit results suffer from inconsistencies between datasets, referred to as tension. This motivates more complicated models for new physics. This thesis considers a model of unstable sterile neutrinos, where the heaviest mass state can decay. First, the phenomenology of unstable sterile neutrinos is explored in the IceCube experiment, a gigaton neutrino detector located at the South Pole. Second, global fits to traditional and unstable sterile neutrino models are combined with one year of data from IceCube. A preference for the unstable sterile neutrino model is found, as well as a reduction in tension. Lastly, a high statistics search for unstable sterile neutrinos is performed in IceCube. The Standard Model is rejected with a p-value of 2.8% and the traditional sterile neutrino model is rejected with a p-value of 4.9%. The best-fit point is [mathematical formula] , [mathematical formula], and g2 = 2.5[pi] ± 1.5[pi], where g is the coupling that mediates the neutrino decay. The best-fit corresponds to a lifetime of the heaviest neutrino of [tau]4/m4 = 6 × 10−16 s/eV. A Bayesian analysis finds a best model with similar sterile parameters.

Magnetic Moments of Active and Sterile Neutrinos in the Laboratory, Astrophysics, and Cosmology

Magnetic Moments of Active and Sterile Neutrinos in the Laboratory, Astrophysics, and Cosmology PDF Author: Nicole Vassh
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
Since most of the neutrino parameters are well-measured, we illustrate precisely the prediction of the Standard Model, minimally extended to allow massive neutrinos, for the electron neutrino magnetic moment. We elaborate on the effects of light sterile neutrinos on the effective electron neutrino magnetic moment measured at the reactors. We explicitly show that the kinematical effects of the neutrino masses are negligible for active and light (eV) sterile neutrinos. We then demonstrate that the interpretation of the recently detected unidentified emission line in the X-ray spectrum of galaxy clusters to be due to the electromagnetic decay of a 7.1 keV sterile neutrino with a "mixing angle" of $\sin^2 2\theta \sim 6.8\times 10^{-11}$ implies the dipole moments of a fourth mass eigenstate to be on the order of $10^{-20}\mu_B$. Lastly, we examine the physics of the early universe when Majorana neutrinos ($\nu_e$, $\nu_{\mu}$, $\nu_{\tau}$) possess transition magnetic moments. These extra couplings beyond the usual weak interaction couplings alter the way neutrinos decouple from the plasma of electrons/positrons and photons. We calculate how transition magnetic moment couplings modify neutrino decoupling temperatures, and then use a full weak, strong, and electromagnetic reaction network to compute corresponding changes in Big Bang Nucleosynthesis abundance yields. We find that light element abundances and other cosmological parameters are sensitive to magnetic couplings on the order of $10^{-10}\mu_B$. Given the recent analysis of sub-MeV Borexino data which constrains Majorana moments to the order of $10^{-11}\mu_B$ or less, we find that changes in cosmological parameters from magnetic contributions to neutrino decoupling temperatures are below the level of upcoming precision observations

Search for EV-scale Sterile Neutrinos with IceCube DeepCore

Search for EV-scale Sterile Neutrinos with IceCube DeepCore PDF Author: Alexander Trettin
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
Englische Version: Neutrino oscillations are the only phenomenon beyond the Standard Model that has been confirmed experimentally to a very high statistical significance. This work presents a measurement of atmospheric neutrino oscillations using eight years of data taken by the IceCube DeepCore detector between 2011 and 2019. The event selection has been improved over that used in previous DeepCore measurements with a particular emphasis on its robustness with respect to systematic uncertainties in the detector properties. The oscillation parameters are estimated via a maximum likelihood fit to binned data in the observed energy and zenith angle, where the expectation is derived from weighted simulated events. This work discusses the simulation and data selection process, as well as the statistical methods employed to give an accurate expectation value under variable detector properties and other systematic uncertainties. The measurement is first performed first under the standard three-flavor oscillation model, where the atmospheric mass splitting and mixing angle are estimated to be $\Delta m 2_{32} = 2.42_{-0.75} {+0.77} \times10 {-3}\;\mathrm{eV} 2$ and $\sin 2\theta_{23} = 0.507_{-0.053} {+0.050}$, respectively. The three-flavor model is then extended by an additional mass eigenstate corresponding to a sterile neutrino with mass splitting $\Delta m 2_{41} = 1\;\mathrm{eV} 2$ that can mix with the active $\nu_\mu$ and $\nu_\tau$ flavor states. No significant signal of a sterile neutrino is observed and the mixing amplitudes between the sterile and active states are constrained to $!U_{\mu 4}! 2