DOCSLIB.ORG

2 Cosmic Rays and Atmospheric Neutrinos 4

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
2 Cosmic Rays and Atmospheric Neutrinos 4 PDF hosted at the Radboud Repository of the Radboud University Nijmegen The following full text is a preprint version which may differ from the publisher's version. For additional information about this publication click this link. http://hdl.handle.net/2066/75873 Please be advised that this information was generated on 2021-10-05 and may be subject to change. S e a r c h in g f o r Q u a n t u m G r a v it y w it h H ig h - e n e r g y A t m o s p h e r ic N e u t r in o s a n d A M A N D A - I I by J o h n L a w r e n c e K e l l e y A dissertation submitted in partial fulfillment of the requirements for the degree of D o c t o r o f P h il o s o p h y (P h y s ic s ) at the U n iv e r s it y o f W is c o n s in - M a d is o n 2008 © 2008 John Lawrence Kelley All Rights Reserved S e a r c h i n g f o r Q u a n t u m G r a v it y w i t h H i g h - e n e r g y A t m o s p h e r i c N e u t r i n o s a n d AMANDA-II John Lawrence Kelley Under the supervision of Professor Albrecht Karle At the University of Wisconsin - Madison The AMANDA-II detector, operating since 2000 in the deep ice at the geographic South Pole, has accumulated a large sample of atmospheric muon neutrinos in the 100 GeV to 10 TeV energy range. The zenith angle and energy distribution of these events can be used to search for various phenomenological signatures of quantum gravity in the neutrino sector, such as violation of Lorentz invariance (VLI) or quantum decoherence (QD). Analyzing a set of 5511 candidate neutrino events collected during 1387 days of livetime from 2000 to 2006, we find no evidence for such effects and set upper limits on VLI and QD parameters using a maximum likelihood method. Given the absence of new flavor-changing physics, we use the same methodology to determine the conventional atmospheric muon neutrino flux above 100 GeV. Albrecht Karle (Adviser) The collaborative nature of science is often one of its more enjoyable aspects, and I owe a debt of gratitude to many people who helped make this work possible. First, I offer my thanks to my adviser, Albrecht Karle, for his support and for the freedom to pursue topics I found interesting (not to mention multiple opportunities to travel to the South Pole). I would like to thank Gary Hill for numerous helpful discussions, especially about statistics, and for always being willing to talk through any problem I might have. Francis Halzen sold me on IceCube during my first visit to Madison, and I have learned from him never to forget the big picture. Many thanks to Teresa Montaruli for her careful analysis and insightful questions, and to Paolo Desiati for listening patiently and offering helpful advice. I thank Dan Hooper for suggesting that I look into the phenomenon of quantum decoherence and thus starting me off on this analysis in the first place. And I thank Kael Hanson for providing fantastic opportunities for involvement in IceCube hardware and software development, and Bob Morse for a chance to explore radio detection techniques. I offer my thanks as well to my officemate and friend, Jim Braun, for a collaboration that has made the past years much more enjoyable. The 0(1000) pots of coffee we have shared were also rather instrumental in fueling this work. I would like to thank my parents, James and Lorraine, for their unflagging encouragement through all of my career-related twists and turns. Finally, I offer my deepest gratitude to my partner, Autumn, for her support, flexibility, and understanding — and for leaving our burrito- and sushi-filled life in San Francisco to allow me to pursue this degree. May the adventures continue. ii C ontents 1 Introduction 1 2 Cosmic Rays and Atmospheric Neutrinos 4 2.1 Cosmic Rays .................................................................................................................................... 4 2.2 Atmospheric Neutrinos and M u o n s ............................................................................................ 7 2.2.1 P ro d u c tio n .......................................................................................................................... 7 2.2.2 Energy Spectrum and Angular D istrib u tio n ............................................................... 7 2.3 Neutrino O scillations....................................................................................................................... 10 3 Quantum Gravity Phenomenology 13 3.1 Violation of Lorentz In v a ria n c e ................................................................................................... 13 3.2 Quantum D ecoherence................................................................................................................... 17 4 Neutrino Detection 21 4.1 General Techniques.......................................................................................................................... 21 4.2 Cerenkov Radiation ....................................................................................................................... 22 4.3 Muon Energy Loss .......................................................................................................................... 23 4.4 Other Event Topologies ................................................................................................................ 23 4.5 B ackground....................................................................................................................................... 25 5 The AMANDA-II Detector 26 5.1 Overview .......................................................................................................................................... 26 5.2 Optical Properties of the Ic e .......................................................................................................... 26 iii 5.3 Data Acquisition and Triggering ................................................................................................ 28 5.4 C a lib ra tio n ....................................................................................................................................... 30 6 Simulation and Data Selection 31 6.1 Simulation .......................................................................................................................................... 31 6.2 Filtering and Track R econstruction............................................................................................ 32 6.3 Quality Cuts .................................................................................................................................... 34 6.3.1 Point-source Cuts ............................................................................................................. 34 6.3.1.1 Likelihood R a tio ................................................................................................ 34 6.3.1.2 Sm oothness.......................................................................................................... 35 6.3.1.3 Paraboloid E r r o r ................................................................................................ 35 6.3.1.4 Flariness and Stability Period ..................................................................... 36 6.3.2 Purity Cuts .......................................................................................................................... 36 6.3.3 High-Nch Excess and Additional Purity C u ts ........................................................... 38 6.4 Final Data Sample .......................................................................................................................... 45 6.5 Effective Area .................................................................................................................................... 47 6.6 A Note on B lin d n e ss....................................................................................................................... 47 7 Analysis Methodology 49 7.1 O bservables....................................................................................................................................... 49 7.2 Statistical Methods .......................................................................................................................... 52 7.2.1 Likelihood Ratio ................................................................................................................ 53 7.2.2 Confidence Intervals .......................................................................................................... 54 7.3 Incorporating Systematic Errors ................................................................................................ 55 7.4 Discussion .......................................................................................................................................... 57 7.5 Complications .................................................................................................................................... 57 7.5.1 Computational Requirements ......................................................................................... 57 7.5.2 Zero D im en sio n s................................................................................................................ 59 7.6 Binning and Final Event Count ................................................................................................... 59 iv 8 Systematic Errors 62 8.1 General Approach .......................................................................................................................... 62 8.2 Sources of Systematic
Load more

Recommended publications
  • Loop Quantum Cosmology, Modified Gravity and Extra Dimensions
    universe Review Loop Quantum Cosmology, Modified Gravity and Extra Dimensions Xiangdong Zhang Department of Physics, South China University of Technology, Guangzhou 510641, China; [email protected] Academic Editor: Jaume Haro Received: 24 May 2016; Accepted: 2 August 2016; Published: 10 August 2016 Abstract: Loop quantum cosmology (LQC) is a framework of quantum cosmology based on the quantization of symmetry reduced models following the quantization techniques of loop quantum gravity (LQG). This paper is devoted to reviewing LQC as well as its various extensions including modified gravity and higher dimensions. For simplicity considerations, we mainly focus on the effective theory, which captures main quantum corrections at the cosmological level. We set up the basic structure of Brans–Dicke (BD) and higher dimensional LQC. The effective dynamical equations of these theories are also obtained, which lay a foundation for the future phenomenological investigations to probe possible quantum gravity effects in cosmology. Some outlooks and future extensions are also discussed. Keywords: loop quantum cosmology; singularity resolution; effective equation 1. Introduction Loop quantum gravity (LQG) is a quantum gravity scheme that tries to quantize general relativity (GR) with the nonperturbative techniques consistently [1–4]. Many issues of LQG have been carried out in the past thirty years. In particular, among these issues, loop quantum cosmology (LQC), which is the cosmological sector of LQG has received increasing interest and has become one of the most thriving and fruitful directions of LQG [5–9]. It is well known that GR suffers singularity problems and this, in turn, implies that our universe also has an infinitely dense singularity point that is highly unphysical.
    [Show full text]
  • Quantum Vacuum Energy Density and Unifying Perspectives Between Gravity and Quantum Behaviour of Matter
    Annales de la Fondation Louis de Broglie, Volume 42, numéro 2, 2017 251 Quantum vacuum energy density and unifying perspectives between gravity and quantum behaviour of matter Davide Fiscalettia, Amrit Sorlib aSpaceLife Institute, S. Lorenzo in Campo (PU), Italy corresponding author, email: [email protected] bSpaceLife Institute, S. Lorenzo in Campo (PU), Italy Foundations of Physics Institute, Idrija, Slovenia email: [email protected] ABSTRACT. A model of a three-dimensional quantum vacuum based on Planck energy density as a universal property of a granular space is suggested. This model introduces the possibility to interpret gravity and the quantum behaviour of matter as two different aspects of the same origin. The change of the quantum vacuum energy density can be considered as the fundamental medium which determines a bridge between gravity and the quantum behaviour, leading to new interest- ing perspectives about the problem of unifying gravity with quantum theory. PACS numbers: 04. ; 04.20-q ; 04.50.Kd ; 04.60.-m. Key words: general relativity, three-dimensional space, quantum vac- uum energy density, quantum mechanics, generalized Klein-Gordon equation for the quantum vacuum energy density, generalized Dirac equation for the quantum vacuum energy density. 1 Introduction The standard interpretation of phenomena in gravitational fields is in terms of a fundamentally curved space-time. However, this approach leads to well known problems if one aims to find a unifying picture which takes into account some basic aspects of the quantum theory. For this reason, several authors advocated different ways in order to treat gravitational interaction, in which the space-time manifold can be considered as an emergence of the deepest processes situated at the fundamental level of quantum gravity.
    [Show full text]
  • Aspects of Loop Quantum Gravity
    Aspects of loop quantum gravity Alexander Nagen 23 September 2020 Submitted in partial fulfilment of the requirements for the degree of Master of Science of Imperial College London 1 Contents 1 Introduction 4 2 Classical theory 12 2.1 The ADM / initial-value formulation of GR . 12 2.2 Hamiltonian GR . 14 2.3 Ashtekar variables . 18 2.4 Reality conditions . 22 3 Quantisation 23 3.1 Holonomies . 23 3.2 The connection representation . 25 3.3 The loop representation . 25 3.4 Constraints and Hilbert spaces in canonical quantisation . 27 3.4.1 The kinematical Hilbert space . 27 3.4.2 Imposing the Gauss constraint . 29 3.4.3 Imposing the diffeomorphism constraint . 29 3.4.4 Imposing the Hamiltonian constraint . 31 3.4.5 The master constraint . 32 4 Aspects of canonical loop quantum gravity 35 4.1 Properties of spin networks . 35 4.2 The area operator . 36 4.3 The volume operator . 43 2 4.4 Geometry in loop quantum gravity . 46 5 Spin foams 48 5.1 The nature and origin of spin foams . 48 5.2 Spin foam models . 49 5.3 The BF model . 50 5.4 The Barrett-Crane model . 53 5.5 The EPRL model . 57 5.6 The spin foam - GFT correspondence . 59 6 Applications to black holes 61 6.1 Black hole entropy . 61 6.2 Hawking radiation . 65 7 Current topics 69 7.1 Fractal horizons . 69 7.2 Quantum-corrected black hole . 70 7.3 A model for Hawking radiation . 73 7.4 Effective spin-foam models .
    [Show full text]
  • Introduction to Loop Quantum Gravity
    Introduction to Loop Quantum Gravity Abhay Ashtekar Institute for Gravitation and the Cosmos, Penn State A broad perspective on the challenges, structure and successes of loop quantum gravity. Addressed to Young Researchers: From Beginning Students to Senior Post-docs. Organization: 1. Historical & Conceptual Setting 2. Structure of Loop Quantum Gravity 3. Outlook: Challenges and Opportunities – p. 1. Historical and Conceptual Setting Einstein’s resistance to accept quantum mechanics as a fundamental theory is well known. However, he had a deep respect for quantum mechanics and was the first to raise the problem of unifying general relativity with quantum theory. “Nevertheless, due to the inner-atomic movement of electrons, atoms would have to radiate not only electro-magnetic but also gravitational energy, if only in tiny amounts. As this is hardly true in Nature, it appears that quantum theory would have to modify not only Maxwellian electrodynamics, but also the new theory of gravitation.” (Albert Einstein, Preussische Akademie Sitzungsberichte, 1916) – p. • Physics has advanced tremendously in the last 90 years but the the problem of unification of general relativity and quantum physics still open. Why? ⋆ No experimental data with direct ramifications on the quantum nature of Gravity. – p. • Physics has advanced tremendously in the last nine decades but the the problem of unification of general relativity and quantum physics is still open. Why? ⋆ No experimental data with direct ramifications on the quantum nature of Gravity. ⋆ But then this should be a theorist’s haven! Why isn’t there a plethora of theories? – p. ⋆ No experimental data with direct ramifications on quantum Gravity.
    [Show full text]
  • Loop Quantum Gravity Alejandro Perez, Centre De Physique Théorique and Université Aix-Marseille II • Campus De Luminy, Case 907 • 13288 Marseille • France
    features Loop quantum gravity Alejandro Perez, Centre de Physique Théorique and Université Aix-Marseille II • Campus de Luminy, case 907 • 13288 Marseille • France. he revolution brought by Einstein’s theory of gravity lies more the notion of particle, Fourier modes, vacuum, Poincaré invariance Tin the discovery of the principle of general covariance than in are essential tools that can only be constructed on a given space- the form of the dynamical equations of general relativity. General time geometry.This is a strong limitation when it comes to quantum covariance brings the relational character of nature into our descrip- gravity since the very notion of space-time geometry is most likely tion of physics as an essential ingredient for the understanding of not defined in the deep quantum regime. Secondly, quantum field the gravitational force. In general relativity the gravitational field is theory is plagued by singularities too (UV divergences) coming encoded in the dynamical geometry of space-time, implying a from the contribution of arbitrary high energy quantum processes. strong form of universality that precludes the existence of any non- This limitation of standard QFT’s is expected to disappear once the dynamical reference system—or non-dynamical background—on quantum fluctuations of the gravitational field, involving the dynam- top of which things occur. This leaves no room for the old view ical treatment of spacetime geometry, are appropriately taken into where fields evolve on a rigid preestablished space-time geometry account. But because of its intrinsically background dependent (e.g. Minkowski space-time): to understand gravity one must definition, standard QFT cannot be used to shed light on this issue.
    [Show full text]
  • An Introduction to Loop Quantum Gravity with Application to Cosmology
    DEPARTMENT OF PHYSICS IMPERIAL COLLEGE LONDON MSC DISSERTATION An Introduction to Loop Quantum Gravity with Application to Cosmology Author: Supervisor: Wan Mohamad Husni Wan Mokhtar Prof. Jo~ao Magueijo September 2014 Submitted in partial fulfilment of the requirements for the degree of Master of Science of Imperial College London Abstract The development of a quantum theory of gravity has been ongoing in the theoretical physics community for about 80 years, yet it remains unsolved. In this dissertation, we review the loop quantum gravity approach and its application to cosmology, better known as loop quantum cosmology. In particular, we present the background formalism of the full theory together with its main result, namely the discreteness of space on the Planck scale. For its application to cosmology, we focus on the homogeneous isotropic universe with free massless scalar field. We present the kinematical structure and the features it shares with the full theory. Also, we review the way in which classical Big Bang singularity is avoided in this model. Specifically, the spectrum of the operator corresponding to the classical inverse scale factor is bounded from above, the quantum evolution is governed by a difference rather than a differential equation and the Big Bang is replaced by a Big Bounce. i Acknowledgement In the name of Allah, the Most Gracious, the Most Merciful. All praise be to Allah for giving me the opportunity to pursue my study of the fundamentals of nature. In particular, I am very grateful for the opportunity to explore loop quantum gravity and its application to cosmology for my MSc dissertation.
    [Show full text]
  • Emergence of Time in Loop Quantum Gravity∗
    Emergence of time in Loop Quantum Gravity∗ Suddhasattwa Brahma,1y 1 Center for Field Theory and Particle Physics, Fudan University, 200433 Shanghai, China Abstract Loop quantum gravity has formalized a robust scheme in resolving classical singu- larities in a variety of symmetry-reduced models of gravity. In this essay, we demon- strate that the same quantum correction which is crucial for singularity resolution is also responsible for the phenomenon of signature change in these models, whereby one effectively transitions from a `fuzzy' Euclidean space to a Lorentzian space-time in deep quantum regimes. As long as one uses a quantization scheme which re- spects covariance, holonomy corrections from loop quantum gravity generically leads to non-singular signature change, thereby giving an emergent notion of time in the theory. Robustness of this mechanism is established by comparison across large class of midisuperspace models and allowing for diverse quantization ambiguities. Con- ceptual and mathematical consequences of such an underlying quantum-deformed space-time are briefly discussed. 1 Introduction It is not difficult to imagine a mind to which the sequence of things happens not in space but only in time like the sequence of notes in music. For such a mind such conception of reality is akin to the musical reality in which Pythagorean geometry can have no meaning. | Tagore to Einstein, 1920. We are yet to come up with a formal theory of quantum gravity which is mathematically consistent and allows us to draw phenomenological predictions from it. Yet, there are widespread beliefs among physicists working in fundamental theory regarding some aspects of such a theory, once realized.
    [Show full text]
  • No-Go Result for Covariance in Models of Loop Quantum Gravity
    PHYSICAL REVIEW D 102, 046006 (2020) No-go result for covariance in models of loop quantum gravity Martin Bojowald Institute for Gravitation and the Cosmos, The Pennsylvania State University, 104 Davey Lab, University Park, Pennsylvania 16802, USA (Received 3 July 2020; accepted 30 July 2020; published 10 August 2020) Based on the observation that the exterior space-times of Schwarzschild-type solutions allow two symmetric slicings, a static spherically symmetric one and a timelike homogeneous one, modifications of gravitational dynamics suggested by symmetry-reduced models of quantum cosmology can be used to derive corresponding modified spherically symmetric equations. Generally covariant theories are much more restricted in spherical symmetry compared with homogeneous slicings, given by 1 þ 1-dimensional dilaton models if they are local. As shown here, modifications used in loop quantum cosmology do not have a corresponding covariant spherically symmetric theory. Models of loop quantum cosmology therefore violate general covariance in the form of slicing independence. Only a generalized form of covariance with a non-Riemannian geometry could consistently describe space-time in models of loop quantum gravity. DOI: 10.1103/PhysRevD.102.046006 I. INTRODUCTION space-time structure in models of loop quantum gravity [9]. Here, we elaborate on this application and use it to Models of black holes in quantum gravity are valuable demonstrate a no-go result that implies the noncovariance not only because their strong-field effects draw consider- of any model of loop quantum gravity, if covariance is able physical interest, but also because they are understood understood in the classical way related to slicing inde- as a consequence of nontrivial dynamical properties of pendence in Riemannian geometry.
    [Show full text]
  • Quantum Gravity: a Primer for Philosophers∗
    Quantum Gravity: A Primer for Philosophers∗ Dean Rickles ‘Quantum Gravity’ does not denote any existing theory: the field of quantum gravity is very much a ‘work in progress’. As you will see in this chapter, there are multiple lines of attack each with the same core goal: to find a theory that unifies, in some sense, general relativity (Einstein’s classical field theory of gravitation) and quantum field theory (the theoretical framework through which we understand the behaviour of particles in non-gravitational fields). Quantum field theory and general relativity seem to be like oil and water, they don’t like to mix—it is fair to say that combining them to produce a theory of quantum gravity constitutes the greatest unresolved puzzle in physics. Our goal in this chapter is to give the reader an impression of what the problem of quantum gravity is; why it is an important problem; the ways that have been suggested to resolve it; and what philosophical issues these approaches, and the problem itself, generate. This review is extremely selective, as it has to be to remain a manageable size: generally, rather than going into great detail in some area, we highlight the key features and the options, in the hope that readers may take up the problem for themselves—however, some of the basic formalism will be introduced so that the reader is able to enter the physics and (what little there is of) the philosophy of physics literature prepared.1 I have also supplied references for those cases where I have omitted some important facts.
    [Show full text]
  • Manifoldlike Causal Sets
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by eGrove (Univ. of Mississippi) University of Mississippi eGrove Electronic Theses and Dissertations Graduate School 2019 Manifoldlike Causal Sets Miremad Aghili University of Mississippi Follow this and additional works at: https://egrove.olemiss.edu/etd Part of the Physics Commons Recommended Citation Aghili, Miremad, "Manifoldlike Causal Sets" (2019). Electronic Theses and Dissertations. 1529. https://egrove.olemiss.edu/etd/1529 This Dissertation is brought to you for free and open access by the Graduate School at eGrove. It has been accepted for inclusion in Electronic Theses and Dissertations by an authorized administrator of eGrove. For more information, please contact [email protected]. Manifoldlike Causal Sets A Dissertation presented in partial fulfillment of requirements for the degree of Doctor of Philosophy in the Department of Physics and Astronomy The University of Mississippi by Miremad Aghili May 2019 Copyright Miremad Aghili 2019 ALL RIGHTS RESERVED ABSTRACT The content of this dissertation is written in a way to answer the important question of manifoldlikeness of causal sets. This problem has importance in the sense that in the continuum limit and in the case one finds a formalism for the sum over histories, the result requires to be embeddable in a manifold to be able to reproduce General Relativity. In what follows I will use the distribution of path length in a causal set to assign a measure for manifoldlikeness of causal sets to eliminate the dominance of nonmanifoldlike causal sets. The distribution of interval sizes is also investigated as a way to find the discrete version of scalar curvature in causal sets in order to present a dynamics of gravitational fields.
    [Show full text]
  • Dimension and Dimensional Reduction in Quantum Gravity
    March 2019 Dimension and Dimensional Reduction in Quantum Gravity S. Carlip∗ Department of Physics University of California Davis, CA 95616 USA Abstract If gravity is asymptotically safe, operators will exhibit anomalous scaling at the ultraviolet fixed point in a way that makes the theory effectively two- dimensional. A number of independent lines of evidence, based on different approaches to quantization, indicate a similar short-distance dimensional reduction. I will review the evidence for this behavior, emphasizing the physical question of what one means by “dimension” in a quantum spacetime, and will dis- cuss possible mechanisms that could explain the universality of this phenomenon. For proceedings of the conference in honor of Martin Reuter: “Quantum Fields—From Fundamental Concepts to Phenomenological Questions” September 2018 arXiv:1904.04379v1 [gr-qc] 8 Apr 2019 ∗email: [email protected] 1. Introduction The asymptotic safety program offers a fascinating possibility for the quantization of gravity, starkly different from other, more common approaches, such as string theory and loop quantum gravity [1–3]. We don’t know whether quantum gravity can be described by an asymptotically safe (and unitary) field theory, but it might be. For “traditionalists” working on quantum gravity, this raises a fundamental question: What does asymptotic safety tell us about the small-scale structure of spacetime? So far, the most intriguing answer to this question involves the phenomenon of short-distance dimensional reduction. It seems nearly certain that, near a nontrivial ultraviolet fixed point, operators acquire large anomalous dimensions, in such a way that their effective dimensions are those of operators in a two-dimensional spacetime [4–6].
    [Show full text]
  • Loop Quantum Gravity
    QUANTUM GRAVITY Loop gravity combines general relativity and quantum theory but it leaves no room for space as we know it – only networks of loops that turn space–time into spinfoam Loop quantum gravity Carlo Rovelli GENERAL relativity and quantum the- ture – as a sort of “stage” on which mat- ory have profoundly changed our view ter moves independently. This way of of the world. Furthermore, both theo- understanding space is not, however, as ries have been verified to extraordinary old as you might think; it was introduced accuracy in the last several decades. by Isaac Newton in the 17th century. Loop quantum gravity takes this novel Indeed, the dominant view of space that view of the world seriously,by incorpo- was held from the time of Aristotle to rating the notions of space and time that of Descartes was that there is no from general relativity directly into space without matter. Space was an quantum field theory. The theory that abstraction of the fact that some parts of results is radically different from con- matter can be in touch with others. ventional quantum field theory. Not Newton introduced the idea of physi- only does it provide a precise mathemat- cal space as an independent entity ical picture of quantum space and time, because he needed it for his dynamical but it also offers a solution to long-stand- theory. In order for his second law of ing problems such as the thermodynam- motion to make any sense, acceleration ics of black holes and the physics of the must make sense.
    [Show full text]