The Aniya model for particle physics

The authors have searched for new physics beyond the Standard Model of elementary particle physics in dielectron decay mode at the CDF (Collider Detector at Fermilab) experiment in {bar p}p collisions at {radical}s = 1.96 TeV. The data were collected during the 2002-2003 runs corresponding to an integrated luminosity of 200 pb{sup -1}. Many extensions of the Standard Model have been proposed. Grand Unified Theories (GUT) assumes a larger gauge symmetry group and predict new gauge bosons. GUT has hierarchy problem in it and there have been many attempts to solve the hierarchy problem. Solutions for the hierarchy problem are supersymmetry, technicolor, large extra dimensions, warped extra dimensions and little Higgs models. The authors analyze the differential distribution of dielectron events in terms of their invariant mass and no significant excess is found in very high mass region. They present a 95% confidence level limit on the production cross section times branching ratio for new resonant particles decaying into an electron pair as a function of invariant mass. New resonant particles include new neutral gauge boson Z', Randall-Sundrum graviton, R-parity violating sneutrino, and technicolor particles. They also present limits on the effective Planck scale of large extra dimensions.

The book studies relations of condensed matter with particle physics and cosmology. The fundamental links between cosmology and particle physics have been well established and is widely exploited in the description of the physics of the early universe (baryogenesis, cosmological nucleosynthesis, etc.). The connection of these two fields with the third ingredient of modern physics — condensed matter — allows us to simulate the least understood features of high-energy physics and cosmology: the properties of the quantum vacuum (also called aether, spacetime foam, quantum foam, Planck medium, etc.). The new concept inspired by condensed matter physics is opposite to the fundamental concept of broken symmetries used in Grand Unification Theory (GUT). In the anti-GUT scenario, gravity and the relativistic quantum field theory, such as the Standard Model of particle physics and GUT, are effective theories. They are emergent phenomena arising in the low-energy corner of the physical vacuum, where the system acquires physical laws and symmetries, which it did not have at higher energy.

In this thesis, we investigate several ways how the structure of a high energy particle physics model constituting a grand unification theory (GUT) in supersymmetry (SUSY) can be inferred from multiple types of information obtained at low energy. First, we calculate the values and 1 sigma ranges of the running quark and lepton Yukawa couplings as well as of the quark mixing parameters at various energy scales to provide useful input for flavour model building in GUTs and other scenarios while including tan beta enhanced SUSY threshold corrections in a simple way. Next, we analyse the naturalness of the Minimal Supersymmetric Standard Model (MSSM) in the light of the discovery of the Higgs boson at the Large Hadron Collider (LHC). In particular, we find that among possible departures from the constrained MSSM (cMSSM) non-universal gaugino masses represent the most promising way to find parameter regions with a fine-tuning of only O(10) even for a Higgs mass of about 126 GeV, compared to O(100) for the cMSSM. In this context, we also discuss the preference for certain GUT-scale Yukawa coupling ratios over others based on fine-tuning. Following that, we study how also the recent determination of the leptonic mixing angle theta^pmns_13 can be accommodated in a simple scenario for GUT models of flavour via charged lepton corrections. This leads us to four conditions that can easily be implemented. In addition, the interplay of the value of theta^pmns_13 with future determinations of the Dirac CP phase delta^pmns is discussed using lepton mixing sum rules. Finally, we study how the double missing partner mechanism as a solution to the doublet-triplet splitting problem can be incorporated into SU(5) GUT models of flavour to comply with the bounds on proton decay. In this context, we argue that the introduction of two adjoints of SU(5) is a compelling idea and calculate its constraints on the GUT scale and dimension five proton decay suppression scale at two loops. We close with general comments on the calculation of the proton lifetime in the considered scenario for flavour models. Multiple appendices are included detailing non-obvious aspects of the calculation and other kinds of valuable information for GUT model building.

社 社 www.scichina.comcsb.scichina.com

Grand Unified Theories (GUTs) offer an attractive framework for flavour models, since they feature relations between quarks and leptons. Combining them with Supersymmetry (SUSY) and flavour symmetries, we derive predictions for the flavour and SUSY flavour structure from various GUT models and discuss how the double missing partner mechanism (DMPM) solution to the doublet-triplet splitting problem can be combined with predictions for GUT scale quark-lepton Yukawa coupling relations. We construct two predictive SUSY SU(5) GUT models with an A4 flavour symmetry, that feature realistic quark-lepton Yukawa coupling ratios and mixing angle relations. These GUT scale predictions arise after GUT symmetry breaking from a novel combination of group theoretical Clebsch-Gordan factors, and we carefully construct additional shaping symmetries and renormalisable messenger sectors to protect the models' predictions from dangerous corrections. The major difference between both models are their respective predictions of a normal and inverse neutrino mass ordering. We perform Markov Chain Monte Carlo analyses, fit to experimental data, and discuss how the models can be tested by present and future experiments. To combine predictive GUT scale quark-lepton Yukawa coupling ratios with the DMPM in SUSY SU(5), we introduce a second GUT breaking Higgs field in the adjoint representation. Two explicit flavour models with different predictions for the GUT scale Yukawa sector are presented, including shaping symmetries and renormalisable messenger sectors, and combined with the DMPM. We calculate the effective masses of the colour triplets mediating proton decay and find that they can be made sufficiently heavy. In SUSY theories, the one-loop SUSY threshold corrections are of particular importance in investigating GUT scale quark-lepton mass relations and thus link a given GUT flavour model to the sparticle spectrum. We calculate the one-loop SUSY threshold corrections of the full MSSM Yukawa coupling matrices in the electroweak-unbroken phase and introduce a new software tool SusyTC as a major extension to the Mathematica package REAP. Finally we find predictions for the CMSSM parameters and sparticle masses from the GUT scale Yukawa coupling ratios used in the flavour models of this thesis.

Over the past couple of decades, the Standard Model of high energy particle physics has clearly established itself as an invaluable tool in the analysis of high energy particle phenomenon. However, from a field theorists point of view, there are many dissatisfying aspects to the model. One of these, is the large number of free parameters in the theory arising from the Yukawa couplings of the Higgs doublet. In this thesis, we examine various issues relating to the Yukawa coupeng structure of high energy particle field theories. We begin by examining extensions to the Standard Model of particle physics which contain additional scalar fields. By appealing to the flavor structure observed in the fermion mass and Kobayashi-Maskawa matrices, we propose a reasonable phenomenological parameterization of the new Yukawa couplings based on the concept of approximate flavor symmetries. It is shown that such a parameterization eliminates the need for discrete symmetries which limit the allowed couplings of the new scalars. New scalar particles which can mediate exotic flavor changing reactions can have masses as low as the weak scale. Next, we turn to the issue of neutrino mass matrices, where we examine a particular texture which leads to matter independent neutrino oscillation results for solar neutrinos. We, then, examine the basis for extremely strict limits placed on flavor changing interactions which also break lepton- and/or baryon-number. These limits are derived from cosmological considerations. Finally, we embark on an extended analysis of proton decay in supersymmetric SO(10) grand unified theories. In such theories, the dominant decay diagrams involve the Yukawa couplings of a heavy triplet superfield. We argue that past calculations of proton decay which were based on the minimal supersymmetric SU(5) model require reexamination because the Yukawa couplings of that theory are known to be wrong.

A concise introduction to the cutting-edge science of particle physics The standard model of particle physics describes our current understanding of nature's fundamental particles and their interactions, yet gaps remain. For example, it does not include a quantum theory of gravity, nor does it explain the existence of dark matter. Once complete, however, the standard model could provide a unified description of the very building blocks of the universe. Researchers have been chasing this dream for decades, and many wonder whether such a dream can ever be made a reality. Can the Laws of Physics Be Unified? is a short introduction to this exciting frontier of physics. The book is accessibly written for students and researchers across the sciences, and for scientifically minded general readers. Paul Langacker begins with an overview of the key breakthroughs that have shaped the standard model, and then describes the fundamental particles, their interactions, and their role in cosmology. He goes on to explain field theory, internal symmetries, Yang-Mills theories, strong and electroweak interactions, the Higgs boson discovery, and neutrino physics. Langacker then looks at the questions that are still unanswered: What is the nature of the mysterious dark matter and dark energy that make up roughly 95 percent of the universe? Why is there more matter than antimatter? How can we reconcile quantum mechanics and general relativity? Can the Laws of Physics Be Unified? describes the promising theoretical ideas and new experiments that could provide answers and weighs our prospects for establishing a truly unified theory of the smallest constituents of nature and their interactions.

Physicists have a tendency to take a reductionist view of the world, in which physics is the base on which all other sciences are founded. While it is a view that may legitimately be questioned, it is interesting to note that its acceptance leads to a curious quandary. Physics has attained a level of theoretical abstraction inconceivable in the other sciences, and this has made possible the philosophical debates that it has engendered. Our probing into the unseen depths of the atomic and subatomic world has removed science further and further from the world of our direct experience and permitted it to rest on layers of inference and extrapolation. Presumably, this has left us with doubts about the meaning of reality. At the level of the more empirical sciences, reality is assumed to be based on our direct experience. That is to say, we define reality in terms of our interactions with the material environment in which we live. We do not question the reality of this immediate world, though it is considered to be in principles dependent on the laws of physics. But if, at its most basic level, we question the reality of the quantum laws on the basis of which we understand the physical world, how can we attribute more certainty to the reality of our direct experience?

Elementary particle physics raises questions that are several thousand years old. What are the fundamental components of matter and how do they interact? These questions are linked to the question of what happened in the very first moments after the creation of the universe. Modern physics systematically tests nature to find answers to these and other fundamental questions. Precise theories are developed that describe various phenomena and at the same time are reduced to a few basic principals of nature. Simplification and reduction have always been guiding concepts of physics. The interplay between experimental data and theoretical descriptions led to the Standard Model of elementary particle physics. It summarizes the laws of nature and is one of most precise descriptions of nature achieved by mankind. Despite the great success of the Standard Model it is not the ultimate theory of everything. Models beyond the Standard Model try to unify all interactions in one grand unified theory. The number of free parameters is attempted to be reduced. Gravity is attempted to be incorporated. Extensions to the Standard Model like supersymmetry address the so-called hierarchy problem. Precision measurements are the key for searches of new particles and new physics. A powerful toolmore » of experimental particle physics are particle accelerators. They provide tests of the Standard Model at smallest scales. New particles are produced and their properties are investigated. In 1995 the heaviest known elementary particle, called top quark, has been discovered at Fermilab. It differs from all other lighter quarks due to the high mass and very short lifetime. This makes the top quark special and an interesting object to be studied. A rich program of top physics at Fermilab investigates whether the top quark is really the particle as described by the Standard Model. The top quark mass is a free parameter of the theory that has been measured precisely. This thesis presents a precise measurement of the top quark mass by the D0 experiment at Fermilab in the dilepton final states. The comparison of the measured top quark masses in different final states allows an important consistency check of the Standard Model. Inconsistent results would be a clear hint of a misinterpretation of the analyzed data set. With the exception of the Higgs boson, all particles predicted by the Standard Model have been found. The search for the Higgs boson is one of the main focuses in high energy physics. The theory section will discuss the close relationship between the physics of the Higgs boson and the top quark.« less

While the observation of nucleon decay would be a smoking gun of Grand Unified Theories (GUTs) in general, the ratios between the decay rates of the various channels carry rich information about the specific GUT model realization. To investigate this fingerprint of GUT models in the context of supersymmetric (SUSY) GUTs, we present the software tool SusyTCProton, which is an extension of the module SusyTC to be used with the REAP package. It allows to calculate nucleon decay rates from the relevant dimension five GUT operators specified at the GUT scale, including the full loop-dressing at the SUSY scale. As an application, we investigate the fingerprints of two example GUT toy models with different flavor structures, performing an MCMC analysis to include the experimental uncertainties for the charged fermion masses and CKM mixing parameters. While both toy models provide equally good fits to the low energy data, we show how they could be distinguished via their predictions of ratios for nucleon decay rates. Together with SusyTCProton we also make the additional module ProtonDecay public. It can be used independently from REAP and allows to calculate nucleon decay rates from given D = 5 and D = 6 operator coefficients (accepting the required SUSY input for the D = 5 case in SLHA format). The D = 6 functionality can also be used to calculate nucleon decay in non-SUSY GUTs.

Focus on Dark Matter

The paper offers an overview of quantum and macro gravity, two of the three pillars of the Grand Unified Theory (GUT), the other thermodynamics, developed in a series of papers since the solution of the gravitational n-body problem in 1997 (J. Nonlinear Analysis, A-Series: Theory, Methods and Applications, Vol. 30, No. 8, 1997, pp. 5021 - 5032) and consolidated in the paper, The Grand Unified Theory (J. Nonlinear Analysis, A-Series: Theory: Method and Applications, Vol. 69, No. 3, 2008, pp. 823 - 831). GUT is further advanced by the paper, The Mathematics of GUT (J. Nonlinear Analysis, A-Series: Theory: Method and Applications, Vol. 71, 2009, pp. e420 - e431) and the discovery of more natural laws in the course of analyzing and explaining the disastrous final flight of the Columbia Space Shuttle in 2004 (J. Nonlinear Studies, Vol. 14, No. 3, 2007, pp. 241 - 260). Qualitative modeling was the key to the development of GUT and its theoretical and practical applications. The relevant natural laws of GUT that provide the foundations of the Unified Theory of Evolution are stated. GUT provides the basis for the development of the electromagnetic engine and the Unified Theory of Evolution, its theoretical application, for the development of appropriate technology for electromagnetic treatment of genetic diseases such as cancer, systemic lupos erythematosus, diabetes, muscular dystrophy and mental disorder, the central focus of this paper.

The generation of the fermion mass hierarchy in the standard model of particle physics is a long-standing puzzle. The recent discoveries from neutrino physics suggest that the mixing in the lepton sector is large compared to the quark mixings. To understand this asymmetry between the quark and lepton mixings is an important aim for particle physics. In this regard, two promising approaches from the theoretical side are grand unified theories and family symmetries. In this paper we try to understand certain general features of grand unified theories with Abelian family symmetries by taking the simplest $SU(5)$ grand unified theory as a prototype. We construct an $SU(5)$ toy model with $U(1{)}_{F}\ensuremath{\bigotimes}{\mathbb{Z}}_{2}^{\ensuremath{'}}\ensuremath{\bigotimes}{\mathbb{Z}}_{2}^{\ensuremath{'}\ensuremath{'}}\ensuremath{\bigotimes}{\mathbb{Z}}_{2}^{\ensuremath{'}\ensuremath{'}\ensuremath{'}}$ family symmetry that, in a natural way, duplicates the observed mass hierarchy and mixing matrices to lowest approximation. The system for generating the mass hierarchy is through a Froggatt-Nielsen type mechanism. One idea that we use in the model is that the quark and charged lepton sectors are hierarchical with small mixing angles while the light neutrino sector is democratic with larger mixing angles. We also discuss some of the difficulties in incorporating finer details into the model without making further assumptions or adding a large scalar sector.

There are some particle physics theories that go beyond the so-called “standard cosmological model” to predict the existence of magnetic monopoles (MMs). The discovery of MMs would be an incredible breakthrough in high-energy physics. The existence of MMs in the early Universe has been speculated and anticipated from Grand Unified Theory. If MMs exist, the inverse powers of the unification mass will not suppress the baryon number violating effects of grand unified gauge theories. Therefore, MM catalyzing nucleon decay is a typical strong interaction. This phenomenon is due to the boundary conditions that must be imposed on the core of MM fermion fields. We present a possible mechanism to explain the formation of the Hot Big Bang Cosmology. The main ingredient in our model is nucleon decay catalyzed by MMs (i.e. the Rubakov–Callan effect). It is shown that Hot Big Bang developed naturally because the luminosity due to the Rubakov–Callan effect is much greater than the Eddington luminosity (i.e. [Formula: see text]).

As discussed in the opening chapter, one of the best ways to understand the realm of validity for an effective theory is to calculate the energy scale where perturbative unitarity breaks down. In the first section of this chapter we do exactly this for the effective theory of gravity coupled to matter as given by the action ( 1.1.10). In the second section we apply the bound to various grand unified theories. In the third section we incorporate renormalisation group (RG) effects into the bounds and are then able to compare the scale at which unitarity breaks down with the scale of strong coupling. We discuss the consequences of the RG improved bounds for various models of particle physics and introduce two models which can lower the scale of quantum gravity in four dimensions. The unitarity bound derived here will also provide an important basis for later chapters.