WorldWideScience

Sample records for f-theory grand unification

  1. Grand unification theory and technicolor

    International Nuclear Information System (INIS)

    Rubakov, V.A.; Shaposhnikov, M.E.

    1983-01-01

    The lecture course can be considered as introduction to the problems concerning grand unification models. The course is incomplete. Such problems as CP-violations in strong interactions and the problem of gravitational interaction inclusion in the scheme of grand unification theory are not touched upon. Models of early unification, in which strong, weak and electromagnetic interactions are compared according to the ''strength'' at energies of about 10 5 -10 6 GeV, are not discussed. Models with horizontal symmetry, considering different generations of quarks and leptons from one viewpoint, are not analyzed. Cosmological applications of supersymmetric unified theories are not considered. Certain problems of standard elementary particle theory, philosophy of the great unification, general properties of the grand unification models and the main principles of the construction of models: the SU(5) model, models on the SO(10) groups, have been considered. The problem of supersymmetric unification hierarchies, supersymmetric generalization of the minimum SU(5) model, supersymmetry violation and the problem of hierarchies, phenomenology of the o.rand unification models, cosmological application and technicolour, are discussed

  2. Effective Higgs theories in supersymmetric grand unification

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Sibo [Chongqing University, Department of Physics, Chongqing (China)

    2017-09-15

    The effective Higgs theories at the TeV scale in supersymmetric SU(5) grand unification models are systematically derived. Restricted to extensions on 5{sub H} containing the Higgs sector we show that only two types of real (vector-like) models and one type of chiral model are found to be consistent with perturbative grand unification. While the chiral model has been excluded by the LHC data, the fate of perturbative unification will be uniquely determined by the two classes of vector-like models. (orig.)

  3. Introduction to grand unification theories

    International Nuclear Information System (INIS)

    Kang, Kyungsik

    1980-01-01

    We introduce the Georgi-Glashow model based on the minimal gauge group SU(5) as a prototype grand unification theory of the electroweak and strong interactions. Simple estimation of sin 2 thetasub(W) in the symmetry limit and the renormalization corrections at the energy scale of Msub(W) are given along wich other successes of the SU(5) model

  4. Grand unification and gravity - selected topics

    International Nuclear Information System (INIS)

    Zee, A.

    1981-09-01

    The material given here was presented in lectures delivered at the 4th Kyoto Summer Institute on Grand Unification and Related Topics. It consists of six sections. The sections are: the family problem, fermion mass hierarchy, maximal local symmetry, operator analysis of new physics, dynamically generated gravity, and Kaluza theory and grand unification. The last section contains a (hopefully) pedagogical introduction to Kaluza theory. For pedagogical completeness, several appendices reviewing some elementary notions of differential geometry have been added

  5. Proton hexality in local grand unification

    Energy Technology Data Exchange (ETDEWEB)

    Foerste, Stefan; Nilles, Hans Peter [Bonn Univ. (Germany). Bethe Center for Theoretical Physics and Physikalisches Institut; Ramos-Sanchez, Saul [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Vaudrevange, Patrick K.S. [Muenchen Univ. (Germany). Arnold Sommerfeld Center for Theoretical Physics

    2010-07-15

    Proton hexality is a discrete symmetry that avoids the problem of too fast proton decay in the supersymmetric extension of the standard model. Unfortunately it is inconsistent with conventional grand unification. We show that proton hexality can be incorporated in the scheme of ''Local Grand Unification'' discussed in the framework of model building in (heterotic) string theory. (orig.)

  6. Local grand unification and string theory

    International Nuclear Information System (INIS)

    Nilles, Hans Peter; Vaudrevange, Patrick K.S.

    2009-09-01

    The low energy effective action of string theory depends strongly on the process of compactification and the localization of fields in extra dimensions. Explicit string constructions towards the minimal supersymmetric standard model (MSSM) reveal interesting results leading to the concept of local grand unification. Properties of the MSSM indicate that we might live at a special location close to an orbifold fixed point rather than a generic point in Calabi-Yau moduli space. We observe an enhancement of (discrete) symmetries that have various implications for the properties of the MSSM such as proton stability as well as solutions to the flavor problem, the m-problem and the strong CP-problem. (orig.)

  7. Grand Unification as a Bridge Between String Theory and Phenomenology

    Energy Technology Data Exchange (ETDEWEB)

    Pati, Jogesh C.

    2006-06-09

    In the first part of the talk, I explain what empirical evidence points to the need for having an effective grand unification-like symmetry possessing the symmetry SU(4)-color in 4D. If one assumes the premises of a future predictive theory including gravity--be it string/M theory or a reincarnation--this evidence then suggests that such a theory should lead to an effective grand unification-like symmetry as above in 4D, near the string-GUT-scale, rather than the standard model symmetry. Advantages of an effective supersymmetric G(224) = SU(2){sub L} x SU(2){sub R} x SU(4){sup c} or SO(10) symmetry in 4D in explaining (1) observed neutrino oscillations, (2) baryogenesis via leptogenesis, and (3) certain fermion mass-relations are noted. And certain distinguishing tests of a SUSY G(224) or SO(10)-framework involving CP and flavor violations (as in {mu} {yields} e{gamma}, {tau} {yields} {mu}{gamma}, edm's of the neutron and the electron) as well as proton decay are briefly mentioned. Recalling some of the successes we have had in our understanding of nature so far, and the current difficulties of string/M theory as regards the large multiplicity of string vacua, some comments are made on the traditional goal of understanding vis a vis the recently evolved view of landscape and anthropism.

  8. Grand Unification as a Bridge Between String Theory and Phenomenology

    Science.gov (United States)

    Pati, Jogesh C.

    In the first part of this paper, we explain what empirical evidence points to the need for having an effective grand unification-like symmetry possessing the symmetry SU(4)-color in 4D. If one assumes the premises of a future predictive theory including gravity — be it string/M-theory or a reincarnation — this evidence then suggests that such a theory should lead to an effective grand unification-like symmetry as above in 4D, near the string-GUT-scale, rather than the standard model symmetry. Advantages of an effective supersymmetric G(224) = SU(2)L × SU(2)R × SU(4)c or SO(10) symmetry in 4D in explaining (i) observed neutrino oscillations, (ii) baryogenesis via leptogenesis, and (iii) certain fermion mass-relations are noted. And certain distinguishing tests of a SUSY G(224) or SO(10)-framework involving CP and flavor violations (as in μ → eγ, τ → μγ, edm's of the neutron and the electron) as well as proton decay are briefly mentioned. Recalling some of the successes we have had in our understanding of nature so far, and the current difficulties of string/M-theory as regards the large multiplicity of string vacua, some comments are made on the traditional goal of understanding vis a vis the recently evolved view of landscape and anthropism.

  9. Grand Unification as a Bridge Between String Theory and Phenomenology

    International Nuclear Information System (INIS)

    Pati, J

    2006-01-01

    In the first part of the talk, I explain what empirical evidence points to the need for having an effective grand unification-like symmetry possessing the symmetry SU(4)-color in 4D. If one assumes the premises of a future predictive theory including gravity--be it string/M theory or a reincarnation--this evidence then suggests that such a theory should lead to an effective grand unification-like symmetry as above in 4D, near the string-GUT-scale, rather than the standard model symmetry. Advantages of an effective supersymmetric G(224) = SU(2) L x SU(2) R x SU(4) c or SO(10) symmetry in 4D in explaining (1) observed neutrino oscillations, (2) baryogenesis via leptogenesis, and (3) certain fermion mass-relations are noted. And certain distinguishing tests of a SUSY G(224) or SO(10)-framework involving CP and flavor violations (as in μ → eγ, τ → μγ, edm's of the neutron and the electron) as well as proton decay are briefly mentioned. Recalling some of the successes we have had in our understanding of nature so far, and the current difficulties of string/M theory as regards the large multiplicity of string vacua, some comments are made on the traditional goal of understanding vis a vis the recently evolved view of landscape and anthropism

  10. Grand unification: quo vadis domine

    International Nuclear Information System (INIS)

    Senjanovic, G.

    1985-01-01

    The present theoretical and experimental situation with grand unification is summarized. The issues of proton decay and the Weinberg angle are addressed, going through the predictions of both the standard SU(5) theory and its supersymmetric extension. The SO(10) theory, which provides a minimal one family model, is then studied. The gravitational characteristics of domain walls and strings are then discussed. It is argued that there is a need to go beyond SO(10) in order to incorporate a unified picture of families. This leads to the prediction of mirror fermions, whose physics is analyzed. 31 refs

  11. The behaviour of effective coupling constants in 'finite' grand unification theories in curved spacetime

    International Nuclear Information System (INIS)

    Buchbinder, I.L.; Odintsov, S.D.; Lichtzier, I.M.

    1989-01-01

    The question of the behaviour of effective coupling constants in one-loop 'finite' grand unification theories in curved spacetime is investigated. It is shown that in strong gravitational fields the effective coupling constant, corresponding to the parameter of non-minimal interaction of scalar and gravitational fields, tends to the conformal value or increases in an exponential fashion. The one-loop effective potential is obtained with accuracy to linear curvature terms. It is shown that, in external supergravity, supersymmetric finite theories admit asymptotic conformal invariance. (Author)

  12. Classification of three-family grand unification in string theory. II. The SU(5) and SU(6) models

    International Nuclear Information System (INIS)

    Kakushadze, Z.; Tye, S.H.

    1997-01-01

    Requiring that supersymmetric SU(5) and SU(6) grand unifications in the heterotic string theory must have three chiral families, adjoint (or higher representation) Higgs fields in the grand unified gauge group, and a non-Abelian hidden sector, we construct such string models within the framework of free conformal field theory and asymmetric orbifolds. Within this framework, we construct all such string models via Z 6 asymmetric orbifolds that include a Z 3 outerautomorphism, the latter yielding a level-three current algebra for the grand unification gauge group SU(5) or SU(6). We then classify all such Z 6 asymmetric orbifolds that result in models with a non-Abelian hidden sector. All models classified in this paper have only one adjoint (but no other higher representation) Higgs field in the grand unified gauge group. This Higgs field is neutral under all other gauge symmetries. The list of hidden sectors for three-family SU(6) string models are SU(2), SU(3), and SU(2)circle-times SU(2). In addition to these, three-family SU(5) string models can also have an SU(4) hidden sector. Some of the models have an apparent anomalous U(1) gauge symmetry. copyright 1997 The American Physical Society

  13. Grand unification: status report

    International Nuclear Information System (INIS)

    Georgi, H.

    1983-01-01

    Grand unification is reviewed with regard to the flavor puzzle and the hierarchy puzzle. Progress in CP and the PQWWKDFS axion is reviewed. The neutrino mass and B-L research, the understanding and assimilation of the language of effective theories (which divide the momentum scale up into regions), with focus on the models, are surveyed. Various unified models are organized according to whether they address the hierarchy puzzle or the flavor puzzle. SU(5), SO(10), E6, and Higgs are considered simple and explicit models. Global symmetry addresses hierarchy puzzle, but the rules are unclear. In SO (18), with regard to hierarchy, perturbation theory breaks down. SO (14) fails for hierarchy because of GIM, b and t problems. Supersymmetry and technicolor with regard to flavor puzzle are questioned. The CP solution of ETC and Composite C models (addressing both flavor and hierarchy) is a minus. Composite A model has no evident virtues, and the basic idea of ETC model needs checking

  14. Gauge coupling unification from unified theories in higher dimensions

    International Nuclear Information System (INIS)

    Hall, Lawrence J.; Nomura, Yasunori

    2002-01-01

    Higher dimensional grand unified theories, with gauge symmetry breaking by orbifold compactification, possess SU(5) breaking at fixed points, and do not automatically lead to tree-level gauge coupling unification. A new framework is introduced that guarantees precise unification--even the leading loop threshold corrections are predicted, although they are model dependent. Precise agreement with the experimental result, α s exp =0.117±0.002, occurs only for a unique theory, and gives α s KK =0.118±0.004±0.003. Remarkably, this unique theory is also the simplest, with SU(5) gauge interactions and two Higgs hypermultiplets propagating in a single extra dimension. This result is more successful and precise than that obtained from conventional supersymmetric grand unification, α s SGUT =0.130±0.004±Δ SGUT . There is a simultaneous solution to the three outstanding problems of 4D supersymmetric grand unified theories: a large mass splitting between Higgs doublets and their color triplet partners is forced, proton decay via dimension five operators is automatically forbidden, and the absence of fermion mass relations amongst light quarks and leptons is guaranteed, while preserving the successful m b /m τ relation. The theory necessarily has a strongly coupled top quark located on a fixed point and part of the lightest generation propagating in the bulk. The string and compactification scales are determined to be around 10 17 GeV and 10 15 GeV, respectively

  15. Reconciling grand unification with strings by anisotropic compactifications

    International Nuclear Information System (INIS)

    Dundee, Ben; Raby, Stuart; Wingerter, Akin

    2008-01-01

    We analyze gauge coupling unification in the context of heterotic strings on anisotropic orbifolds. This construction is very much analogous to effective five-dimensional orbifold grand unified theory field theories. Our analysis assumes three fundamental scales: the string scale M S , a compactification scale M C , and a mass scale for some of the vectorlike exotics M EX ; the other exotics are assumed to get mass at M S . In the particular models analyzed, we show that gauge coupling unification is not possible with M EX =M C , and in fact we require M EX C ∼3x10 16 GeV. We find that about 10% of the parameter space has a proton lifetime (from dimension six gauge exchange) 10 33 yr 0 e + ) 36 yr. The other 80% of the parameter space gives proton lifetimes below Super-Kamiokande bounds. The next generation of proton decay experiments should be sensitive to the remaining parameter space.

  16. Selected topics in grand unification

    International Nuclear Information System (INIS)

    Seckel, D.

    1983-01-01

    This dissertation is a collection of four pieces of research dealing with grand unification. The topics are neutron oscillation, CP violation, magnetic monopole abundance and distribution in neutron stars, and a proposal for an inflationary cosmology driven by stress-energy in domain walls

  17. Phase transitions at finite chemical potential in grand unified theories

    International Nuclear Information System (INIS)

    Bailin, D.; Love, A.

    1984-01-01

    We discuss the circumstances in which non-zero chemical potentials might prevent symmetry restoration in phase transitions in the early universe at grand unification or partial unification scales. The general arguments are illustrated by consideration of SO(10) and SU(5) grand unified theories. (orig.)

  18. Revisiting top-bottom-tau Yukawa unification in supersymmetric grand unified theories

    International Nuclear Information System (INIS)

    Tobe, Kazuhiro; Wells, James D.

    2003-01-01

    Third family Yukawa unification, as suggested by minimal SO(10) unification, is revisited in light of recent experimental measurements and theoretical progress. We characterize unification in a semi-model-independent fashion, and conclude that finite b quark mass corrections from superpartners must be non-zero, but much smaller than naively would be expected. We show that a solution that does not require cancellations of dangerously large tanβ effects in observables implies that scalar superpartner masses should be substantially heavier than the Z scale, and perhaps inaccessible to all currently approved colliders. On the other hand, gauginos must be significantly lighter than the scalars. We demonstrate that a spectrum of anomaly-mediated gaugino masses and heavy scalars works well as a theory compatible with third family Yukawa unification and dark matter observations

  19. LEP constraints on grand unified theories

    International Nuclear Information System (INIS)

    Sarkar, Utpal

    1993-01-01

    Recent developments on grand unified theories (GUTs) in the context of the LEP measurements of the coupling constants are reviewed. The three coupling constants at the electroweak scale have been measured at LEP quite precisely. One can allow these couplings to evolve with energy following the renormalization group equations for the various groups and find out whether all the coupling constants meet at any energy. It was pointed out that the minimal SU(5) grand unified theory fails to satisfy this test. However, various extensions of the theory are still allowed. These extensions include (i) supersymmetric SU(5) GUT, with some arbitrariness in the susy breaking scale arising from the threshold corrections, (ii) non-susy SU(5) GUTs with additional fermions as well as Higgs multiplets, which has masses of the order of TeV, and (iii) non-renormalizable effect of gravity with a fine tuned relation among the coupling constants at the unification energy. The LEP results also constrain GUTs with an intermediate symmetry breaking scale. By adjusting the intermediate symmetry breaking scale, one usually can have unification, but these theories get constrained. For example, the left-right symmetric theories coming from GUTs can be broken only at energies higher than about ∼10 10 GeV. This implies that if right handed gauge bosons are found at energies lower than this scale, then that will rule out the possibility of grand unification. Another recent interesting development on the subject, namely, low energy unification, is discussed in this context. All the coupling constants are unified at energies of the order of ∼10 8 GeV when they are embedded in an SU(15)GUT, with some particular symmetry breaking pattern. But even in this case the results of the intermediate symmetry breaking scale remain unchanged. (author). 16 refs., 3 figs

  20. Supersymmetry and supergravity: Phenomenology and grand unification

    International Nuclear Information System (INIS)

    Arnowitt, R.; Nath, P.

    1993-01-01

    A survey is given of supersymmetry and supergravity and their phenomenology. Some of the topics discussed are the basic ideas of global supersymmetry, the minimal supersymmetric Standard Model (MSSM) and its phenomenology, the basic ideas of local supersymmetry (supergravity), grand unification, supersymmetry breaking in supergravity grand unified models, radiative breaking of SU(2) x U(1), proton decay, cosmological constraints, and predictions of supergravity grand unified models. While the number of detailed derivations are necessarily limited, a sufficient number of results are given so that a reader can get a working knowledge of this field

  1. Local grand unification in the heterotic landscape

    International Nuclear Information System (INIS)

    Schmidt, Jonas

    2009-06-01

    We consider the possibility that the unification of the electroweak interactions and the strong force arises from string theory, at energies significantly lower than the string scale. As a tool, an effective grand unified field theory in six dimensions is derived from an anisotropic orbifold compactification of the heterotic string. It is explicitly shown that all anomalies cancel in the model, though anomalous Abelian gauge symmetries are present locally at the boundary singularities. In the supersymmetric vacuum additional interactions arise from higher-dimensional operators. We develop methods that relate the couplings of the effective theory to the location of the vacuum, and find that unbroken discrete symmetries play an important role for the phenomenology of orbifold models. An efficient algorithm for the calculation of the superpotential to arbitrary order is developed, based on symmetry arguments. We furthermore present a correspondence between bulk fields of the orbifold model in six dimensions, and the moduli fields that arise from compactifying four internal dimensions on a manifold with non-trivial gauge background. (orig.)

  2. Local grand unification in the heterotic landscape

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Jonas

    2009-07-15

    We consider the possibility that the unification of the electroweak interactions and the strong force arises from string theory, at energies significantly lower than the string scale. As a tool, an effective grand unified field theory in six dimensions is derived from an anisotropic orbifold compactification of the heterotic string. It is explicitly shown that all anomalies cancel in the model, though anomalous Abelian gauge symmetries are present locally at the boundary singularities. In the supersymmetric vacuum additional interactions arise from higher-dimensional operators. We develop methods that relate the couplings of the effective theory to the location of the vacuum, and find that unbroken discrete symmetries play an important role for the phenomenology of orbifold models. An efficient algorithm for the calculation of the superpotential to arbitrary order is developed, based on symmetry arguments. We furthermore present a correspondence between bulk fields of the orbifold model in six dimensions, and the moduli fields that arise from compactifying four internal dimensions on a manifold with non-trivial gauge background. (orig.)

  3. Bounds on the number of possible Higgs particles using grand unification and exceptional Lie groups

    International Nuclear Information System (INIS)

    El Naschie, M.S.

    2008-01-01

    The total sum of dimensions of a magnum exceptional Lie symmetry groups hierarchy is 4α-bar o =(4)(137+k o )≅548. Dividing this value among the various quantum fields leads to the possibility of an eight degrees of freedom Higgs field. However analyzing the same situation using sub groups of the largest exceptional Lie group leads to the conclusion that we are likely to find three Higgs particles only at the energy scale of the standard model. Consequently five of the eight degrees of freedom are unlikely to materialize as particles at this particular energy scale. This conclusion is reinforced by an entirely different approach based on grand unification analysis which excludes any grand unification using 4HD, i.e. four Higgs doublets. This leaves us with one, two and three Higgs doublets. Noting that a super symmetric standard model with two Higgs doublets gives almost perfect grand unification and that the result agrees with our exceptional Lie symmetry groups analysis, we exclude everything else. The final result is that we expect to find at least three more Higgs particles leading to a total of 66 elementary particles while at a somewhat higher energy, the expected number of 69 particles found using E-infinity theory is obtained

  4. SO(10) supersymmetric grand unified theories

    Science.gov (United States)

    Dermisek, Radovan

    The origin of the fermion mass hierarchy is one of the most challenging problems in elementary particle physics. In the standard model fermion masses and mixing angles are free parameters. Supersymmetric grand unified theories provide a beautiful framework for physics beyond the standard model. In addition to gauge coupling unification these theories provide relations between quark and lepton masses within families, and with additional family symmetry the hierarchy between families can be generated. We present a predictive SO(10) supersymmetric grand unified model with D 3 x U(1) family symmetry. The hierarchy in fermion masses is generated by the family symmetry breaking D 3 x U(1) → ZN → nothing. This model fits the low energy data in the charged fermion sector quite well. We discuss the prediction of this model for the proton lifetime in light of recent SuperKamiokande results and present a clear picture of the allowed spectra of supersymmetric particles. Finally, the detailed discussion of the Yukawa coupling unification of the third generation particles is provided. We find a narrow region is consistent with t, b, tau Yukawa unification for mu > 0 (suggested by b → sgamma and the anomalous magnetic moment of the muon) with A0 ˜ -1.9m16, m10 ˜ 1.4m16, m16 ≳ 1200 GeV and mu, M1/2 ˜ 100--500 GeV. Demanding Yukawa unification thus makes definite predictions for Higgs and sparticle masses.

  5. Relict gravitational waves in the expanding Universe model and the grand unification scale

    International Nuclear Information System (INIS)

    Veryskin, A.V.; Rubakov, V.A.; Sazhin, M.V.

    1983-01-01

    The amplification of the vacuum fluctuations of the metric in the model of the expanding Universe was considered. The spectrum of the relict gravitational waves was chosen to be independent from the details of an evolution of the Universe after the phase transition. It is shown that the expanding Universe scenario is compatible with the experimental data on the anisotropy of the microwave background only if the vacuum energy density of the symmetric phase is much less than the Planck one. The theories of grand unification with not large values of the unification scale (one and a half order less than the Planck mass) are preferable from the point of view of cosmology

  6. Unification predictions

    International Nuclear Information System (INIS)

    Ghilencea, D.; Ross, G.G.; Lanzagorta, M.

    1997-07-01

    The unification of gauge couplings suggests that there is an underlying (supersymmetric) unification of the strong, electromagnetic and weak interactions. The prediction of the unification scale may be the first quantitative indication that this unification may extend to unification with gravity. We make a precise determination of these predictions for a class of models which extend the multiplet structure of the Minimal Supersymmetric Standard Model to include the heavy states expected in many Grand Unified and/or superstring theories. We show that there is a strong cancellation between the 2-loop and threshold effects. As a result the net effect is smaller than previously thought, giving a small increase in both the unification scale and the value of the strong coupling at low energies. (author). 15 refs, 5 figs

  7. Interplay between grand unification and supersymmetry in SU(5 ...

    Indian Academy of Sciences (India)

    energy MSSM. break the rank, Aulakh and his collaborators [10–12] have showed that R-parity is exact all the way down to low energies. In this case, grand unification tells us something about supersymmetry and even dark matter. In this article ...

  8. Unification beyond GUT's: Gauge-Yukawa unification

    International Nuclear Information System (INIS)

    Kubo, J.; Mondragon, M.; Zoupanos, G.

    1996-01-01

    Gauge-Yukawa Unification (GYU) is a renormalization group invariant functional relation among gauge and Yukawa couplings which holds beyond the unification point in Grand Unified Theories (GUTs). We present here various models where GYU is obtained by requiring the principles of finiteness and reduction of couplings. We examine the consequences of these requirements for the low energy parameters, especially for the top quark mass. The predictions are such that they clearly distinguish already GYU from ordinary GUTs. It is expected that it will be possible to discriminate among the various GYUs when more accurate measurements of the top quark mass are available. (author)

  9. Finite Unification: Theory, Models and Predictions

    CERN Document Server

    Heinemeyer, S; Zoupanos, G

    2011-01-01

    All-loop Finite Unified Theories (FUTs) are very interesting N=1 supersymmetric Grand Unified Theories (GUTs) realising an old field theory dream, and moreover have a remarkable predictive power due to the required reduction of couplings. The reduction of the dimensionless couplings in N=1 GUTs is achieved by searching for renormalization group invariant (RGI) relations among them holding beyond the unification scale. Finiteness results from the fact that there exist RGI relations among dimensional couplings that guarantee the vanishing of all beta-functions in certain N=1 GUTs even to all orders. Furthermore developments in the soft supersymmetry breaking sector of N=1 GUTs and FUTs lead to exact RGI relations, i.e. reduction of couplings, in this dimensionful sector of the theory, too. Based on the above theoretical framework phenomenologically consistent FUTs have been constructed. Here we review FUT models based on the SU(5) and SU(3)^3 gauge groups and their predictions. Of particular interest is the Hig...

  10. Light grand unified theory triplets and Yukawa splitting

    International Nuclear Information System (INIS)

    Rakshit, Subhendu; Shadmi, Yael; Raz, Guy; Roy, Sourov

    2004-01-01

    Triplet-mediated proton decay in grand unified theories (GUTs) is usually suppressed by arranging a large triplet mass. Here we explore instead a mechanism for suppressing the couplings of the triplets to the first and second generations compared to the Yukawa couplings, so that the triplets can be light. This mechanism is based on a 'triplet symmetry' in the context of product-group GUTs. We study two possibilities. The first possibility, which requires the top Yukawa coupling to arise from a nonrenormalizable operator at the GUT scale, is that all triplet couplings to matter are negligible, so that the triplets can be at the weak scale, giving new evidence for grand unification. The second possibility is that some triplet couplings, and in particular Ttb and Tt-barl-bar, are equal to the corresponding Yukawa couplings. This would give a distinct signature of grand unification if the triplets were sufficiently light. However, we derive a model-independent bound on the triplet mass in this case, which is at least 10 6 GeV. Finally, we construct an explicit viable GUT model based on Yukawa splitting, with the triplets at 10 14 GeV, as required for coupling unification to work. This model requires no additional thresholds below the GUT scale

  11. From chaos to unification: U theory vs. M theory

    International Nuclear Information System (INIS)

    Ye, Fred Y.

    2009-01-01

    A unified physical theory called U theory, that is different from M theory, is defined and characterized. U theory, which includes spinor and twistor theory, loop quantum gravity, causal dynamical triangulations, E-infinity unification theory, and Clifford-Finslerian unifications, is based on physical tradition and experimental foundations. In contrast, M theory pays more attention to mathematical forms. While M theory is characterized by supersymmetry string theory, U theory is characterized by non-supersymmetry unified field theory.

  12. Dark matter as the signal of grand unification

    International Nuclear Information System (INIS)

    Kadastik, Mario; Kannike, Kristjan; Raidal, Martti

    2009-01-01

    We argue that the existence of dark matter (DM) is a possible consequence of grand unification (GUT) symmetry breaking. In GUTs like SO(10), discrete Z 2 matter parity (-1) 3(B-L) survives despite broken B-L, and group theory uniquely determines that the only possible Z 2 -odd matter multiplets belong to representation 16. We construct the minimal nonsupersymmetric SO(10) model containing one scalar 16 for DM and study its predictions below M G . We find that electroweak symmetry breaking occurs radiatively due to DM couplings to the standard model Higgs boson. For thermal relic DM the mass range M DM ∼O(0.1-1) TeV is predicted by model perturbativity up to M G . For M DM ∼O(1) TeV to explain the observed cosmic ray anomalies with DM decays, there exists a lower bound on the spin-independent direct detection cross section within the reach of planned experiments.

  13. Asymptotically safe grand unification

    Energy Technology Data Exchange (ETDEWEB)

    Bajc, Borut [J. Stefan Institute,1000 Ljubljana (Slovenia); Sannino, Francesco [CP-Origins & the Danish IAS, University of Southern Denmark,Campusvej 55, DK-5230 Odense M (Denmark); Université de Lyon, France, Université Lyon 1, CNRS/IN2P3, UMR5822 IPNL,F-69622 Villeurbanne Cedex (France)

    2016-12-28

    Phenomenologically appealing supersymmetric grand unified theories have large gauge representations and thus are not asymptotically free. Their ultraviolet validity is limited by the appearance of a Landau pole well before the Planck scale. One could hope that these theories save themselves, before the inclusion of gravity, by generating an interacting ultraviolet fixed point, similar to the one recently discovered in non-supersymmetric gauge-Yukawa theories. Employing a-maximization, a-theorem, unitarity bounds, as well as positivity of other central charges we nonperturbatively rule out this possibility for a broad class of prime candidates of phenomenologically relevant supersymmetric grand unified theories. We also uncover candidates passing these tests, which have either exotic matter or contain one field decoupled from the superpotential. The latter class of theories contains a model with the minimal matter content required by phenomenology.

  14. Probing the design of grand unification through conservation laws

    International Nuclear Information System (INIS)

    Pati, J.C.

    1981-01-01

    The purpose of this talk is to note a few special consequences of gauging ''maximal'' quark-lepton symmetries such as SO(16), which is the maximal symmetry for a single family of fermions. Within these symmetries, violations for B, L and F are spontaneous rather than explicit. Furthermore these symmetries as a rule permit intermediate mass scales approx.(10 3 -10 6 GeV) and (10 8 -10 11 GeV) filling the so-called grand plateau between 10 2 and 10 15 GeV. It has been shown in earlier papers that within these symmetries proton may decay via four alternative models: i.e. proton→one or three leptons or antileptons plus mesons; some of which can coexist. It is now observed that even n-n-bar oscillations can coexist with (B-L) conserving proton-decays of the type p→e + π 0 etc. without posing any conflict with the cosmological generation of baryon-excess; both these processes can possess measurable strengths so as to be amenable to forthcoming searches. Search for alternative decay modes of proton and n-n-bar oscillations, even as processes in second and third generation experiments, would provide valuable information on the question of intermediate mass-scales and thereby on the design of grand unification

  15. Direct mediation, duality and unification

    International Nuclear Information System (INIS)

    Abel, Steven; Khoze, Valentin V.

    2008-01-01

    It is well-known that in scenarios with direct gauge mediation of supersymmetry breaking the messenger fields significantly affect the running of Standard Model couplings and introduce Landau poles which are difficult to avoid. Among other things, this appears to remove any possibility of a meaningful unification prediction and is often viewed as a strong argument against direct mediation. We propose two ways that Seiberg duality can circumvent this problem. In the first, which we call 'deflected-unification', the SUSY-breaking hidden sector is a magnetic theory which undergoes a Seiberg duality to an electric phase. Importantly, the electric version has fewer fundamental degrees of freedom coupled to the MSSM compared to the magnetic formulation. This changes the β-functions of the MSSM gauge couplings so as to push their Landau poles above the unification scale. We show that this scenario is realised for recently suggested models of gauge mediation based on a metastable SCQD-type hidden sector directly coupled to MSSM. The second possibility for avoiding Landau poles, which we call 'dual-unification', begins with the observation that, if the mediating fields fall into complete SU(5) multiplets, then the MSSM+messengers exhibits a fake unification at unphysical values of the gauge couplings. We show that, in known examples of electric/magnetic duals, such a fake unification in the magnetic theory reflects a real unification in the electric theory. We therefore propose that the Standard Model could itself be a magnetic dual of some unknown electric theory in which the true unification takes place. This scenario maintains the unification prediction (and unification scale) even in the presence of Landau poles in the magnetic theory below the GUT scale. We further note that this dual realization of grand unification can explain why Nature appears to unify, but the proton does not decay.

  16. Elementary particles and physics interaction unification

    International Nuclear Information System (INIS)

    Leite-Lopes, J.

    1985-01-01

    Quantum theory and relativity theory are fundamental of relativistic quantum mechanics, quantum field theory, which is the base of elementary particle physics, gauge field theory and basic force unification models. After a short introduction of relativistic equations of the main fields, the free scalar field, the free vector field, the free electromagnetic field and the free spinor field, and of elementary particles and basic interactions, gauge invariance and electromagnetic gauge field are detailed. Then the presentation of internal degrees of freedom, especially isospin, introduces gauge field theory of Yang-Mills. At last weak interactions and strong interactions are presented and lead to grand unification theory in conclusion [fr

  17. Study of theory and phenomenology of some classes of family symmetry and unification models

    International Nuclear Information System (INIS)

    Kane, Gordon L.; King, Steve F.; Peddie, Iain N.R.; Velasco-Sevilla, Liliana

    2005-01-01

    We review and compare theoretically and phenomenologically a number of possible family symmetries, which when combined with unification, could be important in explaining quark, lepton and neutrino masses and mixings, providing new results in several cases. Theoretical possibilities include abelian or non-abelian, symmetric or non symmetric Yukawa matrices, Grand Unification or not. Our main focus is on anomaly-free U(1) family symmetry combined with SU(5) unification, although we also discuss other possibilities. We provide a detailed phenomenological fit of the fermion masses and mixings for several examples, and discuss the supersymmetric flavour issues in such theories, including a detailed analysis of lepton flavour violation. We show that it is not possible to quantitatively and decisively discriminate between these different theoretical possibilities at the present time

  18. Oasis in the desert: weakly broken parity in grand unified theories

    International Nuclear Information System (INIS)

    Senjanovic, G.

    1981-07-01

    A discussion of low energy parity restoration in simple grand unified theories, such as SO(10), is presented. The consistency of phenomenological requirements and unification constraints is emphasized and various predictions of the theory are stressed, in particular: substantially lighter W and Z bosons than in the standard model and increased stability of the proton with tau/sub p/ approx. = 10 38 years

  19. Grand unified theory precursors and nontrivial fixed points in higher-dimensional gauge theories

    International Nuclear Information System (INIS)

    Dienes, Keith R.; Dudas, Emilian; Gherghetta, Tony

    2003-01-01

    Within the context of traditional logarithmic grand unification at M GUT ≅10 16 GeV, we show that it is nevertheless possible to observe certain GUT states such as X and Y gauge bosons at lower scales, perhaps even in the TeV range. We refer to such states as 'GUT precursors'. These states offer an interesting alternative possibility for new physics at the TeV scale, and could be used to directly probe GUT physics even though the scale of gauge coupling unification remains high. Our results also give rise to a Kaluza-Klein realization of nontrivial fixed points in higher-dimensional gauge theories

  20. Lie groups and grand unified theories

    International Nuclear Information System (INIS)

    Gubitoso, M.D.

    1987-01-01

    This work presents some concepts in group theory and Lie algebras and, at same time, shows a method to study and work with semisimple Lie groups, based on Dynkin diagrams. The aproach taken is not completely formal, but it presents the main points of the elaboration of the method, so its mathematical basis is designed with the purpose of making the reading not so cumbersome to those who are interested only in a general picture of the method and its usefulness. At the end it is shown a brief review of gauge theories and two grand-unification models based on SO(13) and E 7 gauge groups. (author) [pt

  1. Vector-like quarks and leptons, SU(5) ⊗ SU(5) grand unification, and proton decay

    International Nuclear Information System (INIS)

    Lee, Chang-Hun; Mohapatra, Rabindra N.

    2017-01-01

    SU(5) ⊗ SU(5) provides a minimal grand unification scheme for fermions and gauge forces if there are vector-like quarks and leptons in nature. We explore the gauge coupling unification in a non-supersymmetric model of this type, and study its implications for proton decay. The properties of vector-like quarks and intermediate scales that emerge from coupling unification play a central role in suppressing proton decay. We find that in this model, the familiar decay mode p→e + π 0 may have a partial lifetime within the reach of currently planned experiments.

  2. F-theory GUTs with U(1) symmetries: Generalities and survey

    International Nuclear Information System (INIS)

    Dolan, Matthew J.; Marsano, Joseph; Saulina, Natalia; Schaefer-Nameki, Sakura

    2011-01-01

    We study the structure of SU(5) F-theory grand unified theory (GUT) models that engineer additional U(1) symmetries. These are highly constrained by a set of relations observed by Dudas and Palti (DP) that originate from the physics of four-dimensional anomaly cancellation. Using the DP relations, we describe a general tension between unification and the suppression of dimension 5 proton decay when one or more U(1)'s are Peccei-Quinn (PQ) symmetries and hypercharge flux is used to break the SU(5) GUT group. We then specialize to spectral cover models, whose global completions in F theory we know how to construct. In that setting, we provide a technical derivation of the DP relations, construct spectral covers that yield all possible solutions to them, and provide a complete survey of spectral cover models for SU(5) GUTs that exhibit two U(1) symmetries.

  3. Unification and supersymmetry

    International Nuclear Information System (INIS)

    Mohapatra, R.N.

    1991-01-01

    This book deals with some of the latest developments in our attempts to construct a unified theory of the fundamental interactions of nature. Among the topics covered are spontaneous symmetry breaking, grand unified theories, supersymmetry, and supergravity. The book starts with a quick review of elementary particle theory and continues with a discussion of composite quarks, leptons, Higgs bosons, and CP violation; it concludes with consideration of supersymmetric unification schemes, in which bosons and leptons are considered in some sense equivalent. The second edition is updated and corrected and contains new chapters on recent developments

  4. The subgroup structure of grand unified theories with application to the fermion mass matrix in 0(10)

    International Nuclear Information System (INIS)

    Feldman, G.; Fulton, T.

    1982-01-01

    A technique, using the orthonormal basis for roots and weights of compact Lie groups, introduced by Van der Waerden and developed by Dynkin (Am. Math. Soc. Transl.; 17: (1950) and Sec 2,6:111 (1957)) provides a convenient framework for discussing mass relations in grand unification theories. The structure constants Nsub(αβ) for SU(R + 1), O(2R + 1), Sp(2R), O(2R) and G(2) are obtained in an appendix, using an approach arising from this basis. The method for obtaining generators of non-regular subalgebras, in terms of generators of the original algebras, is discussed in terms of the basis. It is necessary to know this structure in order to trace the history of particles, originally in some grand unification group, through the various chains of decompositions into subgroups. As an illustration, the methods are applied to finding the minimal, non-trivial, mass relations for fermions in the O(10) grand unification scheme. (author)

  5. Hierarchy of symmetry-breaking scales in SO(10) grand unification and particle masses

    International Nuclear Information System (INIS)

    Asatryan, G.M.; Ioannisyan, A.N.

    1987-01-01

    An SO(10) grand unification model is proposed in which the introduction of an additional discrete symmetry solves the problem of the quark mass spectrum arising in SO(10) breaking schemes with intermediate SU(4) x SU(2)/sub L/ x SU(2)/sub R/ or SU(3)/sub C/ x U(1)/sub B//sub -//sub L/ x SU(2)/sub L/ x SU(2)/sub R/ symmetry. When the breaking of this discrete symmetry is taken into account the condition that there exist only a single light Higgs boson leads to a relation between the b- and t-quark masses which makes it possible to fix the ratio of the grand unification scale M/sub X/ and the quark--lepton symmetry-breaking scale M/sub C/. The specific values of M/sub X/ and M/sub C/ and also the scale of the SU(2)/sub R/ symmetry breaking M/sub R/ depend on the experimental value of the Weinberg angle and are in agreement with the experimental data on proton decay

  6. Symmetry Breaking, Unification, and Theories Beyond the Standard Model

    Energy Technology Data Exchange (ETDEWEB)

    Nomura, Yasunori

    2009-07-31

    A model was constructed in which the supersymmetric fine-tuning problem is solved without extending the Higgs sector at the weak scale. We have demonstrated that the model can avoid all the phenomenological constraints, while avoiding excessive fine-tuning. We have also studied implications of the model on dark matter physics and collider physics. I have proposed in an extremely simple construction for models of gauge mediation. We found that the {mu} problem can be simply and elegantly solved in a class of models where the Higgs fields couple directly to the supersymmetry breaking sector. We proposed a new way of addressing the flavor problem of supersymmetric theories. We have proposed a new framework of constructing theories of grand unification. We constructed a simple and elegant model of dark matter which explains excess flux of electrons/positrons. We constructed a model of dark energy in which evolving quintessence-type dark energy is naturally obtained. We studied if we can find evidence of the multiverse.

  7. M theory: a possible unification of physics laws

    International Nuclear Information System (INIS)

    Fernandes, Alexandre da Silva; Silva, Diego Oliveira Nolasco da; Sousa, Claudio Manoel Gomes de

    2011-01-01

    Full text: Physics has two pillars which are mutually incompatible: quantum field theory and general relativity theory. Throughout its history, various unifications have been made, and in attempts to have a better understanding of the birth and formation of the Universe is also necessary to unify these pillars. This unification may require 11 dimensions, and 6 of them are compressed so that it cannot be seen with existing instruments. These dimensions are the spaces in which the strings vibrate, and each mode of vibration corresponds to a particle. The last dimension shows that the universe is a brane, it is in full motion in the multiverse and the collision of two branes can answer the biggest problem of cosmology: what was the Big Bang? Black holes can be explained using a theory that contains gravity and quantum mechanics. The theory is still being developed, some problems are being solved and the main one is the experimental problem, because it requires energy levels that are not yet achieved by current particle accelerators. This work presents M theory as a possibility of unification between the micro and macro, which maybe leading us to the theory of everything. (author)

  8. M theory: a possible unification of physics laws

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Alexandre da Silva; Silva, Diego Oliveira Nolasco da; Sousa, Claudio Manoel Gomes de [Universidade Catolica de Brasilia (UCB), DF (Brazil)

    2011-07-01

    Full text: Physics has two pillars which are mutually incompatible: quantum field theory and general relativity theory. Throughout its history, various unifications have been made, and in attempts to have a better understanding of the birth and formation of the Universe is also necessary to unify these pillars. This unification may require 11 dimensions, and 6 of them are compressed so that it cannot be seen with existing instruments. These dimensions are the spaces in which the strings vibrate, and each mode of vibration corresponds to a particle. The last dimension shows that the universe is a brane, it is in full motion in the multiverse and the collision of two branes can answer the biggest problem of cosmology: what was the Big Bang? Black holes can be explained using a theory that contains gravity and quantum mechanics. The theory is still being developed, some problems are being solved and the main one is the experimental problem, because it requires energy levels that are not yet achieved by current particle accelerators. This work presents M theory as a possibility of unification between the micro and macro, which maybe leading us to the theory of everything. (author)

  9. Higgsless grand unified theory breaking and trinification

    International Nuclear Information System (INIS)

    Carone, Christopher D.; Conroy, Justin M.

    2004-01-01

    Boundary conditions on an extra dimensional interval can be chosen to break bulk gauge symmetries and to reduce the rank of the gauge group. We consider this mechanism in models with gauge trinification. We determine the boundary conditions necessary to break the trinified gauge group directly down to that of the standard model. Working in an effective theory for the gauge-symmetry-breaking parameters on a boundary, we examine the limit in which the grand-unified theory-breaking-sector is Higgsless and show how one may obtain the low-energy particle content of the minimal supersymmetric standard model. We find that gauge unification is preserved in this scenario, and that the differential gauge coupling running is logarithmic above the scale of compactification. We compare the phenomenology of our model to that of four dimensional 'trinified' theories

  10. An approach to gauge hierarchy in the minimal SU(5) model of grand unification

    International Nuclear Information System (INIS)

    Ghose, P.

    1982-08-01

    It is shown that if all mass generation through spontaneous symmetry breaking is predominantly caused by scalar loops in the minimal SU(5) model of grand unification, it is possible to have an arbitrarily large gauge hierarchy msub(x) >> msub(w) with all Higgs bosons superheavy. No fine tuning is necessary in every order. (author)

  11. Neutrino masses and large mixings as a indirect signature of grand unified theory

    International Nuclear Information System (INIS)

    Maekawa, Nobuhiro

    2015-01-01

    Grand unified theory (GUT) unifies not only three forces (electromagnetic force, strong force and weak force) but also quarks and leptons. As an experimental support for the unification of forces, it is well-known that three gauge couplings meet at a scale (the GUT scale). However, it is not so well-known that there is an experimental support even for the unification of matters (quarks and leptons). We explain the indirect support in this document and show that the important key is what the neutrino experiments have revealed for 20 years. Concretely, for the unification of matters in SU(5) GUT, various observed hierarchies of quark and lepton masses and mixings can be understood only from one assumption that '10 dimensional fields of SU(5) induce stronger hierarchy for the Yukawa couplings than 5-bar fields'. For this explanation, the knowledges on neutrino masses and mixings are critical. In the end, we comment E 6 unification in which the above assumption in the SU(5) GUT can be induced. (author)

  12. Grand unification and supergravity

    International Nuclear Information System (INIS)

    Nanopoulos, D.V.

    Grand Unified Theories (GUTs) are very successful, but they suffer from fine-tuning or hierarchy problems. It seems that more symmetry beyond the gauge symmetry is needed and indeed supersymmetric GUTs may provide the correct framework in solving the hierarchy problems. These are reviewed. From the results discussed, it is seen that for the first time in particle physics, gravity seems to play a dominant role. It may be responsible for GUT breaking, SU(2) x U(1) breaking, fermion masses, proton decay and a consistent cosmological picture. Supergravity seems to offer a consistent, effective theory for energies below the Planck scale to N=1 local SUSY but also, in the context of N=8 extended supergravity with a dynamically realized SU(8), there may be a consistent fundamental unified theory of all interactions. (U.K.)

  13. On hypercharge flux and exotics in F-theory GUTs

    CERN Document Server

    Dudas, Emilian; 10.1007

    2010-01-01

    We study SU(5) Grand Unified Theories within a local framework in F-theory with multiple extra U(1) symmetries arising from a small monodromy group. The use of hypercharge flux for doublet-triplet splitting implies massless exotics in the spectrum that are protected from obtaining a mass by the U(1) symmetries. We find that lifting the exotics by giving vacuum expectation values to some GUT singlets spontaneously breaks all the U(1) symmetries which implies that proton decay operators are induced. If we impose an additional R-parity symmetry by hand we find all the exotics can be lifted while proton decay operators are still forbidden. These models can retain the gauge coupling unification accuracy of the MSSM at 1-loop. For models where the generations are distributed across multiple curves we also present a motivation for the quark-lepton mass splittings at the GUT scale based on a Froggatt-Nielsen approach to flavour.

  14. SO(10) - Grand unification and fermion masses

    International Nuclear Information System (INIS)

    Oezer, A.D.

    2005-01-01

    In this work, we study SO(10) grand unification in its full extent by using different explicit matrix representations which exhibit the structure of SO(10) in a very transparent way. Our approach consists mainly of two stages: We derive the explicit expressions of the mass-eigenvalues and mass-eigenstates of the physical gauge bosons from a mass squared-matrix that contains all the information about the mixing parameters among the gauge fields and the phases which are sources for CP violation. In the light of this analysis, we derive the explicit expressions for the interaction Lagrangians of the charged currents, the neutral currents and the charged and colored currents in SO(10). We present explicit expressions of the vector and axial-vector couplings of the two neutral currents in SO(10). We show how the baryon, lepton and baryon minus lepton number violating processes and their explicit CP violating phases are accommodated in the SO(10) theory. The Higgs potential that we use to implement in the Higgs mechanism is constructed in a most general fashion through a careful study of the Higgs fields of SO(10), where we give special emphasis on illustrating the explicit matrix representation of these Higgs fields. The potential part of the Higgs Lagrangian will give us the properties of the minimum of the vacuum, and the kinetic part will give us the mass-squared matrix of the gauge bosons via spontaneous symmetry breakdown. The same Higgs multiplets will be coupled to fermions through a democratic Yukawa matrix. Thereby, we derive explicit expressions for the fermion masses of the third family including Majorana and Dirac masses for neutrinos. We introduce a flavor-eigenbasis for neutrinos and find the mass-eigenstates and mass-eigenvalues of the neutrinos. Explicit expressions for CP violation in the neutrino sector are obtained. In the second stage of our work, we evaluate all the above mentioned quantities. In addition, we present the values of the physical

  15. Implications of results from the CERN e+e- collider LEP for SO(10) grand unification with two intermediate stages

    International Nuclear Information System (INIS)

    Deshpande, N.G.; Keith, E.; Pal, P.B.

    1993-01-01

    We consider the breaking of the grand unification group SO(10) to the standard model gauge group through several chains containing two intermediate stages. Using the values of the gauge coupling constants at a scale M Z derived from recent data from the CERN e + e- collider LEP, we determine the range of their intermediate and unification scales. In particular, we identify those chains that permit new gauge structure at relatively low energy (∼1 TeV)

  16. Grand unification and the fundamental problems of classical cosmology

    International Nuclear Information System (INIS)

    Turner, M.S.

    1981-01-01

    The accomplishments of classical cosmology are reviewed. In particular, the hot big bang model provides a reliable framework for understanding the evolution of the universe back to times at least as early as approx. 0.01 s after the big bang. At present there are (at least) six fundamental problems which have not yet been (completely) resolved. They are: (1) the origin of the baryon number-to-entropy ratio, (2) the origin of the isotropy, (3) the origin of the homogeneity and inhomogeneity, (4) the origin of the flatness, (5) the cosmological constant, and (6) the monopole problem. The role that grand unification has played, and may play in the resolution of these puzzles is discussed. Guth's inflationary universe, which addresses five of these six problems, is reviewed

  17. Introduction to quantum field theory

    International Nuclear Information System (INIS)

    Kazakov, D.I.

    1988-01-01

    The lectures appear to be a continuation to the introduction to elementary principles of the quantum field theory. The work is aimed at constructing the formalism of standard particle interaction model. Efforts are made to exceed the limits of the standard model in the quantum field theory context. Grand unification models including strong and electrical weak interactions, supersymmetric generalizations of the standard model and grand unification theories and, finally, supergravitation theories including gravitation interaction to the universal scheme, are considered. 3 refs.; 19 figs.; 2 tabs

  18. Low energy implications of minimal superstring unification

    International Nuclear Information System (INIS)

    Khalil, S.; Vissani, F.; Masiero, A.

    1995-11-01

    We study the phenomenological implications of effective supergravities based on string vacua with spontaneously broken N =1 supersymmetry by dilation and moduli F-terms. We further require Minimal String Unification, namely that large string threshold corrections ensure the correct unification of the gauge couplings at the grand unification scale. The whole supersymmetric mass spectrum turns out to be determined in terms of only two independent parameters, the dilaton-moduli mixing angle and the gravitino mass. In particular we discuss the region of the parameter space where at least one superpartner is ''visible'' at LEPII. We find that the most likely candidates are the scalar partner of the right-handed electron and the lightest chargino, with interesting correlations between their masses and with the mass of the lightest higgs. We show how discovering SUSY particles at LEPII might rather sharply discriminate between scenarios with pure dilaton SUSY breaking and mixed dilaton-moduli breaking. (author). 10 refs, 7 figs

  19. Infrared fixed points and fixed lines in the top-bottom-tau sector in supersymmetric grand unification

    International Nuclear Information System (INIS)

    Schrempp, B.

    1994-10-01

    The two loop 'top-down' renormalization group flow for the top, bottom and tau Yukawa couplings, from μ=M GUT ≅O(10 16 GeV) to μ≅m t , is explored in the framework of supersymmetric grand unification; reproduction of the physical bottom and tau masses is required. Instead of following the recent trend of implementing exact Yukawa coupling unification i) a search for infrared (IR) fixed lines and fixed points in the m t pole -tan β plane is performed and ii) the extent to which these imply approximate Yukawa unification is determined. In the m t pole -tan β plane two IR fixed lines, intersecting in an IR fixed point, are located. The more attractive fixed line has a branch of almost constant top mass, m t pole ≅168≅180 GeV (close to the experimental value), for the large interval 2.5 GUT approximately. The less attractive fixed line as well as the fixed point at m t pole ≅170 GeV, tan β≅55 implement approximate top-bottom Yukawa unification at all scales μ. The renormalization group flow is attracted towards the IR fixed point by way of the more attractive IR fixed line. The fixed point and lines are distinct from the much quoted effective IR fixed point m t pole ≅O(200 GeV) sin β. (orig.)

  20. Elementary particle theory

    International Nuclear Information System (INIS)

    Marciano, W.J.

    1984-12-01

    The present state of the art in elementary particle theory is reviewed. Topics include quantum electrodynamics, weak interactions, electroweak unification, quantum chromodynamics, and grand unified theories. 113 references

  1. Dynkin weights and global supersymmetry in grand unification

    International Nuclear Information System (INIS)

    Frampton, P.H.; Kephart, T.W.

    1982-01-01

    The requirement that supersymmetry be unbroken in a supersymmetrized gauge theory is shown to imply vanishing Dynkin weight of the components of the Higgs field representation receiving vacuum expectation values. As a corollary a compact expression is obtained for the Dynkin weights of general SU(N) representations. Examples are given for supersymmetrized grand unified theories

  2. Gauge coupling unification in heterotic string models with gauge mediated supersymmetry breaking

    International Nuclear Information System (INIS)

    Anandakrishnan, Archana; Raby, Stuart

    2011-01-01

    We calculate the weak scale minimal supersymmetric standard model spectrum starting from a heterotic string theory compactified on an anisotropic orbifold. Supersymmetry breaking is mediated by vectorlike exotics that arise naturally in heterotic string theories. The messengers that mediate supersymmetry breaking come in incomplete grand unified theory (GUT) multiplets and give rise to nonuniversal gaugino masses at the GUT scale. Models with nonuniversal gaugino masses at the GUT scale have the attractive feature of allowing for precision gauge coupling unification at the GUT scale with negligible contributions from threshold corrections near the unification scale. The unique features of this minimally supersymmetric standard model spectrum are light gluinos and also large mass differences between the lightest and the next-to-lightest neutralinos and charginos which could lead to interesting signatures at the colliders.

  3. Proceedings of the fourth workshop on grand unification

    Energy Technology Data Exchange (ETDEWEB)

    Weldon, H.A.; Langacker, P.; Steinhardt, P.J.

    1983-01-01

    This book compiles the papers presented at the fourth conference of grand unified theories of nuclear physics held in University of Pennsylvania April 1983. The topics covered were proton decay theory; angular distribution and flux of atmospheric neutrinos; atmospheric neutrinos and astrophysical neutrinos in proton decay experiments; review of future nucleon decay experiments; monopole experiments; searches for magnetic monopole; monopoles, gauge, fields and anomalies; darkmatter, galaxies and voids; adiabatic fluctuations; supersymmetry, supergravity, and Kaluza-Klein theories; superstring theory and superunification.

  4. Supersymmetric grand unified theories from quarks to strings via SUSY GUTs

    CERN Document Server

    Raby, Stuart

    2017-01-01

    These course-tested lectures provide a technical introduction to Supersymmetric Grand Unified Theories (SUSY GUTs), as well as a personal view on the topic by one of the pioneers in the field. While the Standard Model of Particle Physics is incredibly successful in describing the known universe it is, nevertheless, an incomplete theory with many free parameters and open issues. An elegant solution to all of these quandaries is the proposed theory of SUSY GUTs. In a GUT, quarks and leptons are related in a simple way by the unifying symmetry and their electric charges are quantized, further the relative strength of the strong, weak and electromagnetic forces are predicted. SUSY GUTs additionally provide a framework for understanding particle masses and offer candidates for dark matter. Finally, with the extension of SUSY GUTs to string theory, a quantum-mechanically consistent unification of the four known forces (including gravity) is obtained. The book is organized in three sections: the first section contai...

  5. Cosmological implications of grand unified theories

    International Nuclear Information System (INIS)

    Nanopoulos, D.V.

    1982-01-01

    These lectures, mainly devoted to the cosmological implications of GUTs, also include the essential ingredients of GUTs and some of their important applications to particle physics. Section 1 contains some basic points concerning the structure of the standard strong and electroweak interactions prior to grand unification. A detailed expose of GUTs is attempted in sect. 2, including their basci principles and their consequences for particle physics. The minimal, simplest GUT, SU 5 is analysed in some detail and it will be used throughout these lectures as the GUT prototype. Finally, sect. 3 contains the most important cosmological implications of GUTs, including baryon number generation in the early Universe (in rather lengthy detail), dissipative processes in the very early Universe, grand unified monopoles, etc. (orig./HSI)

  6. Squark and slepton mass relations in grand unified theories

    International Nuclear Information System (INIS)

    Cheng, H.; Hall, L.J.

    1995-01-01

    In the minimal supersymmetric standard model, assuming universal scalar masses at large energies, there are four intragenerational relations between the masses of the squarks and sleptons for each light generation. In this paper we study the scalar mass relations which follow only from the assumption that at large energies there is a grand unified theory which leads to a significant prediction of the weak mixing angle. Two new intragenerational mass relations for each of the light generations are derived. In addition, a third mass relation is found which relates the Higgs boson masses, the masses of the third generation scalars, and the masses of the scalars of the lighter generations. Verification of a fourth mass relation, involving only the charged slepton masses, provides a signal for SO(10) unification

  7. Gauge hierarchy problem in grand unified theories

    International Nuclear Information System (INIS)

    Alhendi, H.A.A.

    1982-01-01

    In grand unification schemes, several mass scales are to be introduced, with some of them much larger than all the others, to cope with experimental observations, in which elementary particles of higher masses require higher energy to observe them than elementary particles of lower masses. There have been controversial arguments in the literature on such hierarchical scale structure, when radiative corrections are taken into account. It has been asserted that the gauge hierarchy depends on the choice of the subtraction point (in the classical field space), of the four-point function at zero external momentum. It also has been asserted that the gauge hierarchy problem whenever it is possible to be maintained in one sector of particles, it also is possible to be maintained in the other sectors. These two problems have been studied in a prototype model, namely an 0(3)-model with two triplets of real scalar Higgs fields. Our analysis shows that, within ordinary perturbation theory, none of these two problems is quite correct

  8. Gauge unification in highly anisotropic string compactifications

    International Nuclear Information System (INIS)

    Hebecker, A.; Trapletti, M.

    2005-01-01

    It is well known that heterotic string compactifications have, in spite of their conceptual simplicity and aesthetic appeal, a serious problem with precision gauge coupling unification in the perturbative regime of string theory. Using both a duality-based and a field-theoretic definition of the boundary of the perturbative regime, we reevaluate the situation in a quantitative manner. We conclude that the simplest and most promising situations are those where some of the compactification radii are exceptionally large, corresponding to highly anisotropic orbifold models. Thus, one is led to consider constructions which are known to the effective field-theorist as higher-dimensional or orbifold grand unified theories (orbifold GUTs). In particular, if the discrete symmetry used to break the GUT group acts freely, a non-local breaking in the larger compact dimensions can be realized, leading to a precise gauge coupling unification as expected on the basis of the MSSM particle spectrum. Furthermore, a somewhat more model dependent but nevertheless very promising scenario arises if the GUT breaking is restricted to certain singular points within the manifold spanned by the larger compactification radii

  9. Leptoquark mechanism of neutrino masses within the grand unification framework

    Science.gov (United States)

    Doršner, Ilja; Fajfer, Svjetlana; Košnik, Nejc

    2017-06-01

    We demonstrate the viability of the one-loop neutrino mass mechanism within the framework of grand unification when the loop particles comprise scalar leptoquarks (LQs) and quarks of the matching electric charge. This mechanism can be implemented in both supersymmetric and non-supersymmetric models and requires the presence of at least one LQ pair. The appropriate pairs for the neutrino mass generation via the up-type and down-type quark loops are S_3-R_2 and S_{1, 3}-\\tilde{R}_2, respectively. We consider two distinct regimes for the LQ masses in our analysis. The first regime calls for very heavy LQs in the loop. It can be naturally realized with the S_{1, 3}-\\tilde{R}_2 scenarios when the LQ masses are roughly between 10^{12} and 5 × 10^{13} GeV. These lower and upper bounds originate from experimental limits on partial proton decay lifetimes and perturbativity constraints, respectively. Second regime corresponds to the collider accessible LQs in the neutrino mass loop. That option is viable for the S_3-\\tilde{R}_2 scenario in the models of unification that we discuss. If one furthermore assumes the presence of the type II see-saw mechanism there is an additional contribution from the S_3-R_2 scenario that needs to be taken into account beside the type II see-saw contribution itself. We provide a complete list of renormalizable operators that yield necessary mixing of all aforementioned LQ pairs using the language of SU(5). We furthermore discuss several possible embeddings of this mechanism in SU(5) and SO(10) gauge groups.

  10. Leptoquark mechanism of neutrino masses within the grand unification framework

    Energy Technology Data Exchange (ETDEWEB)

    Dorsner, Ilja [University of Split, Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture in Split (FESB), Split (Croatia); Fajfer, Svjetlana; Kosnik, Nejc [University of Ljubljana, Department of Physics, Ljubljana (Slovenia); Jozef Stefan Institute, Jamova 39, P. O. Box 3000, Ljubljana (Slovenia)

    2017-06-15

    We demonstrate the viability of the one-loop neutrino mass mechanism within the framework of grand unification when the loop particles comprise scalar leptoquarks (LQs) and quarks of the matching electric charge. This mechanism can be implemented in both supersymmetric and non-supersymmetric models and requires the presence of at least one LQ pair. The appropriate pairs for the neutrino mass generation via the up-type and down-type quark loops are S{sub 3}-R{sub 2} and S{sub 1,3}-R{sub 2}, respectively. We consider two distinct regimes for the LQ masses in our analysis. The first regime calls for very heavy LQs in the loop. It can be naturally realized with the S{sub 1,3}-R{sub 2} scenarios when the LQ masses are roughly between 10{sup 12} and 5 x 10{sup 13} GeV. These lower and upper bounds originate from experimental limits on partial proton decay lifetimes and perturbativity constraints, respectively. Second regime corresponds to the collider accessible LQs in the neutrino mass loop. That option is viable for the S{sub 3}-R{sub 2} scenario in the models of unification that we discuss. If one furthermore assumes the presence of the type II see-saw mechanism there is an additional contribution from the S{sub 3}-R{sub 2} scenario that needs to be taken into account beside the type II see-saw contribution itself. We provide a complete list of renormalizable operators that yield necessary mixing of all aforementioned LQ pairs using the language of SU(5). We furthermore discuss several possible embeddings of this mechanism in SU(5) and SO(10) gauge groups. (orig.)

  11. Electroweak symmetry breaking and mass spectra in six-dimensional gauge-Higgs grand unification

    Science.gov (United States)

    Hosotani, Yutaka; Yamatsu, Naoki

    2018-02-01

    The mass spectra of the standard model particles are reproduced in the SO(11) gauge-Higgs grand unification in six-dimensional warped space without introducing exotic light fermions. Light neutrino masses are explained by the gauge-Higgs seesaw mechanism. We evaluate the effective potential of the four-dimensional Higgs boson appearing as a fluctuation mode of the Aharonov-Bohm phase θ_H in the extra-dimensional space, and show that the dynamical electroweak symmetry breaking takes place with the Higgs boson mass m_H ˜ 125 GeV and θ_H ˜ 0.1. The Kaluza-Klein mass scale in the fifth dimension is approximately given by m_KK ˜ 1.230 TeV/sin θ_H.

  12. Particle physics models of inflation in supergravity and grand unification

    International Nuclear Information System (INIS)

    Kostka, Philipp Manuel

    2010-01-01

    In the first part of this thesis, we study classes of hybrid and chaotic inflation models in four-dimensional N=1 supergravity. Therein, the η-problem can be resolved relying on fundamental symmetries in the Kaehler potential. Concretely, we investigate explicit realizations of superpotentials, in which the flatness of the inflaton potential is protected at tree level by a shift symmetry or a Heisenberg symmetry in the Kaehler potential. In the latter case, the associated modulus field can be stabilized during inflation by supergravity effects. In the context of hybrid inflation, a novel class of models, to which we refer as ''tribrid inflation,'' turns out to be particularly compatible with such symmetry solutions to the η-problem. Radiative corrections due to operators in the superpotential, which break the respective symmetry, generate the required small slope of the inflaton potential. Additional effective operators in the Kaehler potential can reduce the predicted spectral index so that it agrees with latest observational data. Within a model of chaotic inflation in supergravity with a quadratic potential, we apply the Heisenberg symmetry to allow for viable inflation with super-Planckian field values, while the associated modulus is stabilized. We show that radiative corrections are negligible in this context. In the second part, the tribrid inflation models are extended to realize gauge non-singlet inflation. This is applied to the matter sector of supersymmetric Grand Unified Theories based on the Pati-Salam gauge group. For the specific scenario in which the right-handed sneutrino is the inflaton, we study the scalar potential in a D-flat valley. We show that despite potentially dangerous two-loop corrections, the required flatness of the potential can be maintained. The reason for this is the strong suppression of gauge interactions of the inflaton field due to its symmetry breaking vacuum expectation value. In addition, the production of stable

  13. Particle physics models of inflation in supergravity and grand unification

    Energy Technology Data Exchange (ETDEWEB)

    Kostka, Philipp Manuel

    2010-12-03

    In the first part of this thesis, we study classes of hybrid and chaotic inflation models in four-dimensional N=1 supergravity. Therein, the {eta}-problem can be resolved relying on fundamental symmetries in the Kaehler potential. Concretely, we investigate explicit realizations of superpotentials, in which the flatness of the inflaton potential is protected at tree level by a shift symmetry or a Heisenberg symmetry in the Kaehler potential. In the latter case, the associated modulus field can be stabilized during inflation by supergravity effects. In the context of hybrid inflation, a novel class of models, to which we refer as ''tribrid inflation,'' turns out to be particularly compatible with such symmetry solutions to the {eta}-problem. Radiative corrections due to operators in the superpotential, which break the respective symmetry, generate the required small slope of the inflaton potential. Additional effective operators in the Kaehler potential can reduce the predicted spectral index so that it agrees with latest observational data. Within a model of chaotic inflation in supergravity with a quadratic potential, we apply the Heisenberg symmetry to allow for viable inflation with super-Planckian field values, while the associated modulus is stabilized. We show that radiative corrections are negligible in this context. In the second part, the tribrid inflation models are extended to realize gauge non-singlet inflation. This is applied to the matter sector of supersymmetric Grand Unified Theories based on the Pati-Salam gauge group. For the specific scenario in which the right-handed sneutrino is the inflaton, we study the scalar potential in a D-flat valley. We show that despite potentially dangerous two-loop corrections, the required flatness of the potential can be maintained. The reason for this is the strong suppression of gauge interactions of the inflaton field due to its symmetry breaking vacuum expectation value. In addition, the

  14. Minimal SUSY SO(10) and Yukawa unification

    International Nuclear Information System (INIS)

    Okada, Nobuchika

    2013-01-01

    The minimal supersymmetric (SUSY) SO(10) model, where only two Higgs multiplets {10⊕126-bar} are utilized for Yukawa couplings with matter fields, can nicely fit the neutrino oscillation parameters as well as charged fermion masses and mixing angles. In the fitting of the fermion mass matrix data, the largest element in the Yukawa coupling with the 126-bar -plet Higgs (Y 126 ) is found to be of order one, so that the right see-saw scale should be provided by Higgs vacuum expectation values (VEVs) of β(10 14 GeV). This fact causes a serious problem, namely, the gauge coupling unification is spoiled because of the presence of many exotic Higgs multiples emerging at the see-saw scale. In order to solve this problem, we consider a unification between bottom-quark and tau Yukawa couplings (b - τ Yukawa coupling unification) at the grand unified theory (GUT) scale, due to threshold corrections of superpartners to the Yukawa couplings at the 1 TeV scale. When the b - τ Yukawa coupling unification is very accurate, the largest element in Y 126 can become β(0.01), so that the right see-saw scale is realized by the GUT scale VEV and the usual gauge coupling unification is maintained. Since the b - τ Yukawa unification alters the Yukawa coupling data at the GUT scale, we re-analyze the fitting of the fermion mass matrix data by taking all the relevant free parameters into account. Unfortunately, we find that no parameter region shows up to give a nice fit for the current neutrino oscillation data and therefore, the usual picture of the gauge coupling unification cannot accommodate the fermion mass matrix data fitting in our procedure.

  15. Grand unification and the double beta-decay

    International Nuclear Information System (INIS)

    Faessler, A.

    1992-01-01

    Models of the unification of the electroweak and the strong interaction predict that the neutrino is a Majorana particle and therefore essentially identical with its own antiparticle. In such grand unified models the neutrino has also a finite mass and a slight right-handed weak interaction, since the model is left-right symmetric. These models have also left handed and right-handed vector bosons to mediate the weak interactions. If these models are correct the neutrinoless double beta-decay is feasable. Thus if one finds the neutrinoless double beta-decay one knows that the standard model can not be correct in which the neutrino is a Dirac particle and therefore different from its antiparticle. Although the neutrinoless double beta-decay has not been seen it is possible to extract from the lower limits of the lifetime against the double neutrinoless beta-decay upper limits for the effective electron-neutrino mass and for the effective mixing angle of the right-handed and the left-handed vector bosons mediating the weak interaction. One also can obtain an effective upper limit for the mass ratio of the light and the heavy vector bosons. The extraction of this physical quantities from the data is made difficult due to the fact that the weak interaction must not be diagonal in the representation of the mass matrix of the six neutrinos requested by such left-right symmetric models. (author)

  16. Grand unification in the projective plane

    International Nuclear Information System (INIS)

    Hebecker, A.

    2004-01-01

    A 6-dimensional grand unified theory with the compact space having the topology of a real projective plane, i.e., a 2-sphere with opposite points identified, is considered. The space is locally flat except for two conical singularities where the curvature is concentrated. One supersymmetry is preserved in the effective 4d theory. The unified gauge symmetry, for example SU(5), is broken only by the non-trivial global topology. In contrast to the Hosotani mechanism, no adjoint Wilson-line modulus associated with this breaking appears. Since, locally, SU(5) remains a good symmetry everywhere, no UV-sensitive threshold corrections arise and SU(5)-violating local operators are forbidden. Doublet-triplet splitting can be addressed in the context of a 6d N=2 super Yang-Mills theory with gauge group SU(6). If this symmetry is first broken to SU(5) at a fixed point and then further reduced to the standard model group in the above non-local way, the two light Higgs doublets of the MSSM are predicted by the group-theoretical and geometrical structure of the model. (author)

  17. Strings: A possible alternative explanation for the Unification of Gravitation Field and Electromagnetic Field

    Science.gov (United States)

    Rivera, Susana

    Throughout the last century, since the last decades of the XIX century, until present day, there had been many attempts to achieve the unification of the Forces of Nature. First unification was done by James Clerk Maxwell, with his Electromagnetic Theory. Then Max Plank developed his Quantum Theory. In 1905, Albert Einstein gave birth to the Special Relativity Theory, and in 1916 he came out with his General Relativity Theory. He noticed that there was an evident parallelism between the Gravitational Force, and the Electromagnetic Force. So, he tried to unify these forces of Nature. But Quantum Theory interposed on his way. On the 1940’s it had been developed the Quantum Electrodynamics (QED), and with it, the unified field theory had an arise interest. On the 60’s and 70’s there was developed the Quantum Chromodynamics (QCD). Along with these theories came the discovery of the strong interaction force and weak interaction force. And though there had been many attempts to unify all these forces of the nature, it could only be achieved the Unification of strong interaction, weak interaction and Electromagnetic Force. On the late 80”s and throughout the last two decades, theories such as “super-string theory”, “or the “M-theory”, among others, groups of Scientists, had been doing grand efforts and finally they came out with the unification of the forces of nature, being the only limitation the use of more than 11 dimensions. Using an ingenious mathematical tool known as the super symmetries, based on the Kaluza - Klein work, they achieve this goal. The strings of these theories are in the rank of 10-33 m. Which make them undetectable. There are many other string theories. The GEUFT theory is based on the existence of concentrated energy lines, which vibrates, expands and contracts, submitting and absorbing energy, matter and antimatter, and which yields a determined geometry, that gives as a result the formation of stars, galaxies, nebulae, clusters

  18. Nontrivial asymptotically nonfree gauge theories and dynamical unification of couplings

    International Nuclear Information System (INIS)

    Kubo, J.

    1995-01-01

    Evidence for the nontriviality of asymptotically nonfree (ANF) Yang-Mills theories is found on the basis of optimized perturbation theory. It is argued that these theories with matter couplings can be made nontrivial by means of the reduction of couplings, leading to the idea of the dynamical unification of couplings (DUC). The second-order reduction of couplings in the ANF SU(3)-gauged Higgs-Yukawa theory, which is assumed to be nontrivial here, is carried out to motivate independent investigations on its nontriviality and DUC

  19. Family unification in five and six dimensions

    International Nuclear Information System (INIS)

    Babu, K.S.; Barr, S.M.; Kyae, Bumseok

    2002-01-01

    In family unification models, all three families of quarks and leptons are grouped together into an irreducible representation of a simple gauge group, thus unifying the standard model gauge symmetries and a gauged family symmetry. Large orthogonal groups, and the exceptional groups E 7 and E 8 , have been much studied for family unification. The main theoretical difficulty of family unification is the existence of mirror families at the weak scale. It is shown here that family unification without mirror families can be realized in simple five-dimensional and six-dimensional orbifold models similar to those recently proposed for SU(5) and SO(10) grand unification. It is noted that a family unification group that survived to near the weak scale and whose coupling extrapolated to high scales unified with those of the standard model would be evidence, accessible in principle at low energy, of the existence of small (Planckian or GUT-scale) extra dimensions

  20. Gauge theory and gravitation

    International Nuclear Information System (INIS)

    Kikkawa, Keiji; Nakanishi, Noboru; Nariai, Hidekazu

    1983-01-01

    These proceedings contain the articles presented at the named symposium. They deal with geometrical aspects of gauge theory and gravitation, special problems in gauge theories, quantum field theory in curved space-time, quantum gravity, supersymmetry including supergravity, and grand unification. See hints under the relevant topics. (HSI)

  1. Third-generation effects on fermion mass predictions in supersymmetric grand unified theories

    International Nuclear Information System (INIS)

    Naculich, S.G.

    1993-01-01

    Relations among fermion masses and mixing angles at the scale of grand unification are modified at lower energies by renormalization group running induced by gauge and Yukawa couplings. In supersymmetric theories, the b quark and τ lepton Yukawa couplings, as well as the t quark coupling, may cause significant running if tanβ, the ratio of Higgs field expectation values, is large. We present approximate analytic expressions for the scaling factors for fermion masses and CKM matrix elements induced by all three third generation Yukawa couplings. We then determine how running caused by the third generation of fermions affects the predictions arising from three possible forms for the Yukawa coupling matrices at the GUT scale: the Georgi-Jarlskog, Giudice, and Fritzsch textures

  2. Grand unified theories

    International Nuclear Information System (INIS)

    Langacker, P.

    1981-01-01

    In this talk I discuss the present status of these theories and of their observational and experimental implications. In section II, I briefly review the standard SU 3 sup(c) x SU 2 x U 1 model of the strong and electroweak interactions. Although phenomenologically successful, the standard model leaves many questions unanswered. Some of these questions are addressed by grand unified theories, which are defined and discussed in Section III. The Georgi-Glashow SU 5 model is described, as are theories based on larger groups such as SO 10 , E 6 , or SO 16 . It is emphasized that there are many possible grand unified theories and that it is an experimental problem not only to test the basic ideas but to discriminate between models. (orig./HSI)

  3. Confronting the conventional ideas of grand unification with fermion masses, neutrino oscillations and proton decay

    Energy Technology Data Exchange (ETDEWEB)

    Pati, J C [Department of Physics, University of Maryland, College Park (United States) and Stanford Linear Accelerator Center, Menlo Park (United States)

    2002-09-15

    It is noted that one is now in possession of a set of facts, which may be viewed as the matching pieces of a puzzle; in that all of them can be resolved by just one idea - that is grand unification. These include: (i) the observed family-structure, (ii) quantization of electric charge, (iii) meeting of the three gauge couplings, (iv) neutrino oscillations; in particular the mass squared-difference {delta}m{sup 2}({nu}{sub {mu}} - {nu}{sub {tau}}) (suggested by SuperK), (v) the intricate pattern of the masses and mixings of the fermions, including the smallness of V{sub cb} and the largeness of {theta}{sub {nu}{sub {mu}{nu}}{sub {tau}}}{sup osc}, and (vi) the need for B-L as a generator to implement baryogenesis (via leptogenesis). All these pieces fit beautifully together within a single puzzle board framed by supersymmetric unification, based on SO(10) or a string-unified G(224)-symmetry. The two notable pieces of the puzzle still missing, however, are proton decay and supersymmetry. A concrete proposal is presented, within a predictive SO(10)/G(224)- framework, that successfully describes the masses and mixings of all fermions, including the neutrinos - with eight predictions, all in agreement with observation. Within this framework, a systematic study of proton decay is carried out, which (a) pays special attention to its dependence on the fermion masses, including the superheavy Majorana masses of the right-handed neutrinos, and (b) limits the threshold corrections so as to preserve natural coupling unification. The study updates prior work by Babu, Pati and Wilczek, in the context of both MSSM and its (interesting) variant, the so-called ESSM, by allowing for improved values of the matrix elements and of the short and long-distance renormalization effects. It shows that a conservative upper limit on the proton lifetime is about (1/3 - 2) x 10{sup 34} years, with {nu}-barK{sup +} being the dominant decay mode, and quite possibly {mu}{sup p}+K{sup 0} and e

  4. Confronting the conventional ideas of grand unification with fermion masses, neutrino oscillations and proton decay

    International Nuclear Information System (INIS)

    Pati, J.C.

    2002-01-01

    It is noted that one is now in possession of a set of facts, which may be viewed as the matching pieces of a puzzle; in that all of them can be resolved by just one idea - that is grand unification. These include: (i) the observed family-structure, (ii) quantization of electric charge, (iii) meeting of the three gauge couplings, (iv) neutrino oscillations; in particular the mass squared-difference Δm 2 (ν μ - ν τ ) (suggested by SuperK), (v) the intricate pattern of the masses and mixings of the fermions, including the smallness of V cb and the largeness of θ ν μ ν τ osc , and (vi) the need for B-L as a generator to implement baryogenesis (via leptogenesis). All these pieces fit beautifully together within a single puzzle board framed by supersymmetric unification, based on SO(10) or a string-unified G(224)-symmetry. The two notable pieces of the puzzle still missing, however, are proton decay and supersymmetry. A concrete proposal is presented, within a predictive SO(10)/G(224)- framework, that successfully describes the masses and mixings of all fermions, including the neutrinos - with eight predictions, all in agreement with observation. Within this framework, a systematic study of proton decay is carried out, which (a) pays special attention to its dependence on the fermion masses, including the superheavy Majorana masses of the right-handed neutrinos, and (b) limits the threshold corrections so as to preserve natural coupling unification. The study updates prior work by Babu, Pati and Wilczek, in the context of both MSSM and its (interesting) variant, the so-called ESSM, by allowing for improved values of the matrix elements and of the short and long-distance renormalization effects. It shows that a conservative upper limit on the proton lifetime is about (1/3 - 2) x 10 34 years, with ν-barK + being the dominant decay mode, and quite possibly μ p +K 0 and e + π 0 being prominent. This in turn strongly suggests that an improvement in the current

  5. Grand unification in higher dimensions with split supersymmetry

    International Nuclear Information System (INIS)

    Schuster, Philip C.

    2006-01-01

    We investigate gauge coupling unification in higher dimensional GUT models with split supersymmetry. We focus on 5d and 6d orbifold GUTs, which permit a simple solution to several problems of 4D GUTs as well as control over GUT scale threshold corrections. In orbifold GUTs, calculable threshold corrections can raise or lower the prediction for α s (M Z ) in a way that depends on the location of Higgs fields. On the other hand, split supersymmetry lowers the prediction for α s (M Z ). Consequently, split supersymmetry changes the preferred location of the Higgs fields in orbifold GUTs. In the simplest models, we find that gauge coupling unification favors higgs doublets that live on the orbifold fixed points instead of in the bulk. In addition, relatively high scales of supersymmetry breaking of 10 10±2 GeV are generically favored

  6. Supersymmetry, supergravity, and unification

    CERN Document Server

    Nath, Pran

    2017-01-01

    This unique book gives a modern account of particle physics and gravity based on supersymmetry and supergravity, two of the most significant developments in theoretical physics since general relativity. The book begins with a brief overview of the history of unification and then goes into a detailed exposition of both fundamental and phenomenological topics. The topics in fundamental physics include Einstein gravity, Yang-Mills theory, anomalies, the standard model, supersymmetry and supergravity, and the construction of supergravity couplings with matter and gauge fields, as well as computational techniques for SO(10) couplings. The topics of phenomenological interest include implications of supergravity models at colliders, CP violation, and proton stability, as well as topics in cosmology such as inflation, leptogenesis, baryogenesis, and dark matter. The book is intended for graduate students and researchers seeking to master the techniques for building grand unified models.

  7. Grand unified theories. Pt. 2

    International Nuclear Information System (INIS)

    Ellis, J.

    1982-01-01

    The author gives an introduction to the construction of grand unified theories on the base of the SU(3)xSU(2)xU(1) model of the strong, weak, and electromagnetic interactions. Especially he discusses the proton decay, neutrino masses and oscillations, and cosmological implications in connection with grand unified theories. (orig./HSI)

  8. Proton decay: Numerical simulations confront grand unification

    International Nuclear Information System (INIS)

    Brower, R.C.; Maturana, G.; Giles, R.C.; Moriarty, K.J.M.; Samuel, S.

    1985-01-01

    The Grand Unified Theories of the electromagnetic, weak and strong interactions constitute a far reaching attempt to synthesize our knowledge of theoretical particle physics into a consistent and compelling whole. Unfortunately, many quantitative predictions of such unified theories are sensitive to the analytically intractible effects of the strong subnuclear theory (Quantum Chromodynamics or QCD). The consequence is that even ambitious experimental programs exploring weak and super-weak interaction effects often fail to give definitive theoretical tests. This paper describes large-scale calculations on a supercomputer which can help to overcome this gap between theoretical predictions and experimental results. Our focus here is on proton decay, though the methods described are useful for many weak processes. The basic algorithms for the numerical simulation of QCD are well known. We will discuss the advantages and challenges of applying these methods to weak transitions. The algorithms require a very large data base with regular data flow and are natural candidates for vectorization. Also, 32-bit floating point arithmetic is adequate. Thus they are most naturally approached using a supercomputer alone or in combination with a dedicated special purpose processor. (orig.)

  9. The origin of baryon number and related problems

    International Nuclear Information System (INIS)

    Schramm, D.N.; Turner, M.S.

    1980-01-01

    The possibility of cosmological baryon production, as motivated by grand unification, is discussed. It is postulated that the application of grand unified theories of particle interactions may explain the origin of baryons in the universe. (C.F.)

  10. Flavor hierarchy in SO(10) grand unified theories via 5-dimensional wave-function localization

    Science.gov (United States)

    Kitano, Ryuichiro; Li, Tianjun

    2003-06-01

    A mechanism to generate fermion-mass hierarchy in SO(10) grand unified theories is considered. We find that the lopsided family structure, which is suitable to the large angle Mikheyev-Smirnov-Wolfenstein solution to solar neutrino oscillation, is realized without introducing extra matter fields if the hierarchy originates from the wave-function profile in an extra dimension. Unlike the Froggatt-Nielsen mechanism, the SO(10) breaking effect may directly contribute to the source of the hierarchy, i.e., the bulk mass terms. It naturally explains the difference of the hierarchical patterns between the quark and the lepton sectors. We also find the possibility of horizontal unification, in which three generations of matter fields are unified to a 3-dimensional representation of an SU(2) gauge group.

  11. Flavor hierarchy in SO(10) grand unified theories via 5-dimensional wave-function localization

    International Nuclear Information System (INIS)

    Kitano, Ryuichiro; Li Tianjun

    2003-01-01

    A mechanism to generate fermion-mass hierarchy in SO(10) grand unified theories is considered. We find that the lopsided family structure, which is suitable to the large angle Mikheyev-Smirnov-Wolfenstein solution to solar neutrino oscillation, is realized without introducing extra matter fields if the hierarchy originates from the wave-function profile in an extra dimension. Unlike the Froggatt-Nielsen mechanism, the SO(10) breaking effect may directly contribute to the source of the hierarchy, i.e., the bulk mass terms. It naturally explains the difference of the hierarchical patterns between the quark and the lepton sectors. We also find the possibility of horizontal unification, in which three generations of matter fields are unified to a 3-dimensional representation of an SU(2) gauge group

  12. Vectorlike particles, Z‧ and Yukawa unification in F-theory inspired E6

    Science.gov (United States)

    Karozas, Athanasios; Leontaris, George K.; Shafi, Qaisar

    2018-03-01

    We explore the low energy implications of an F-theory inspired E6 model whose breaking yields, in addition to the MSSM gauge symmetry, a Z‧ gauge boson associated with a U (1) symmetry broken at the TeV scale. The zero mode spectrum of the effective low energy theory is derived from the decomposition of the 27 and 27 ‾ representations of E6 and we parametrise their multiplicities in terms of a minimum number of flux parameters. We perform a two-loop renormalisation group analysis of the gauge and Yukawa couplings of the effective theory model and estimate lower bounds on the new vectorlike particles predicted in the model. We compute the third generation Yukawa couplings in an F-theory context assuming an E8 point of enhancement and express our results in terms of the local flux densities associated with the gauge symmetry breaking. We find that their values are compatible with the ones computed by the renormalisation group equations, and we identify points in the parameter space of the flux densities where the t - b - τ Yukawa couplings unify.

  13. Vectorlike particles, Z′ and Yukawa unification in F-theory inspired E6

    Directory of Open Access Journals (Sweden)

    Athanasios Karozas

    2018-03-01

    Full Text Available We explore the low energy implications of an F-theory inspired E6 model whose breaking yields, in addition to the MSSM gauge symmetry, a Z′ gauge boson associated with a U(1 symmetry broken at the TeV scale. The zero mode spectrum of the effective low energy theory is derived from the decomposition of the 27 and 27‾ representations of E6 and we parametrise their multiplicities in terms of a minimum number of flux parameters. We perform a two-loop renormalisation group analysis of the gauge and Yukawa couplings of the effective theory model and estimate lower bounds on the new vectorlike particles predicted in the model. We compute the third generation Yukawa couplings in an F-theory context assuming an E8 point of enhancement and express our results in terms of the local flux densities associated with the gauge symmetry breaking. We find that their values are compatible with the ones computed by the renormalisation group equations, and we identify points in the parameter space of the flux densities where the t−b−τ Yukawa couplings unify.

  14. Theory of elementary particles. Proceedings

    International Nuclear Information System (INIS)

    Luest, D.; Weigt, G.

    1994-03-01

    These proceedings contain most of the invited talks ans short communications presented at the named symposium. These concern developments in field theory in connection with string models, grand unification, and quantum gravity. See hints under the relevant topics. (HSI)

  15. Gauge coupling unification in realistic free-fermionic string models

    International Nuclear Information System (INIS)

    Dienes, K.R.; Faraggi, A.E.

    1995-01-01

    We discuss the unification of gauge couplings within the framework of a wide class of realistic free-fermionic string models which have appeared in the literature, including the flipped SU(5), SO(6)xSO(4), and various SU(3)xSU(2)xU(1) models. If the matter spectrum below the string scale is that of the Minimal Supersymmetric Standard Model (MSSM), then string unification is in disagreement with experiment. We therefore examine several effects that may modify the minimal string predictions. First, we develop a systematic procedure for evaluating the one-loop heavy string threshold corrections in free-fermionic string models, and we explicitly evaluate these corrections for each of the realistic models. We find that these string threshold corrections are small, and we provide general arguments explaining why such threshold corrections are suppressed in string theory. Thus heavy thresholds cannot resolve the disagreement with experiment. We also study the effect of non-standard hypercharge normalizations, light SUSY thresholds, and intermediate-scale gauge structure, and similarly conclude that these effects cannot resolve the disagreement with low-energy data. Finally, we examine the effects of additional color triplets and electroweak doublets beyond the MSSM. Although not required in ordinary grand unification scenarios, such states generically appear within the context of certain realistic free-fermionic string models. We show that if these states exist at the appropriate thresholds, then the gauge couplings will indeed unify at the string scale. Thus, within these string models, string unification can be in agreement with low-energy data. (orig.)

  16. Gauge field theories

    International Nuclear Information System (INIS)

    Leite Lopes, J.

    1981-01-01

    The book is intended to explain, in an elementary way, the basic notions and principles of gauge theories. Attention is centred on the Salem-Weinberg model of electro-weak interactions, as well as neutrino-lepton scattering and the parton model. Classical field theory, electromagnetic, Yang-Mills and gravitational gauge fields, weak interactions, Higgs mechanism and the SU(5) model of grand unification are also discussed. (U.K.)

  17. Group theory approach to unification of gravity with internal symmetry gauge interactions. Part 1

    International Nuclear Information System (INIS)

    Samokhvalov, S.E.; Vanyashin, V.S.

    1990-12-01

    The infinite group of deformed diffeomorphisms of space-time continuum is put into the basis of the Gauge Theory of Gravity. This gives rise to some new ways for unification of gravity with other gauge interactions. (author). 7 refs

  18. Research program in elementary particle theory, 1980. Progress report

    International Nuclear Information System (INIS)

    Sudarshan, E.C.G.; Ne'eman, Y.

    1980-01-01

    Research is reported for these subject areas: particle physics in relativistic astrophysics and cosmology; phenomenology of weak and electromagnetic interactions; strong interaction physics, QCD, and quark-parton physics; quantum field theory, quantum mechanics and fundamental problems; groups, gauges, and grand unified theories; and supergeometry, superalgebra, and unification

  19. Technicolor and Beyond: Unification in Theory Space

    DEFF Research Database (Denmark)

    Sannino, Francesco

    2010-01-01

    The salient features of models of dynamical electroweak symmetry breaking are reviewed. The ideal walking idea is introduced according to which one should carefully take into account the effects of the extended technicolor dynamics on the technicolor dynamics itself. The effects amount at the enh......The salient features of models of dynamical electroweak symmetry breaking are reviewed. The ideal walking idea is introduced according to which one should carefully take into account the effects of the extended technicolor dynamics on the technicolor dynamics itself. The effects amount...... supersymmetry and technicolor. The reason is to provide a unification of different extensions of the standard model. For example, this means that one can recover, according to the parameters and spectrum of the theory distinct extensions of the standard model, from supersymmetry to technicolor and unparticle...

  20. Research program in elementary particle theory, 1980. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Sudarshan, E. C.G.; Ne' eman, Y.

    1980-01-01

    Research is reported for these subject areas: particle physics in relativistic astrophysics and cosmology; phenomenology of weak and electromagnetic interactions; strong interaction physics, QCD, and quark-parton physics; quantum field theory, quantum mechanics and fundamental problems; groups, gauges, and grand unified theories; and supergeometry, superalgebra, and unification. (GHT)

  1. On the standard model group in F-theory

    International Nuclear Information System (INIS)

    Choi, Kang-Sin

    2014-01-01

    We analyze the standard model gauge group SU(3) x SU(2) x U(1) constructed in F-theory. The non-Abelian part SU(3) x SU(2) is described by a surface singularity of Kodaira type. Blow-up analysis shows that the non-Abelian part is distinguished from the naive product of SU(3) and SU(2), but that it should be a rank three group along the chain of E n groups, because it has non-generic gauge symmetry enhancement structure responsible for desirablematter curves. The Abelian part U(1) is constructed from a globally valid two-form with the desired gauge quantum numbers, using a similar method to the decomposition (factorization) method of the spectral cover. This technique makes use of an extra section in the elliptic fiber of the Calabi-Yau manifold, on which F-theory is compactified. Conventional gauge coupling unification of SU(5) is achieved, without requiring a threshold correction from the flux along the hypercharge direction. (orig.)

  2. DESY: Theory Workshop 1994

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    For 1994, the traditional annual DESY Theory Workshop was devoted to supersymmetry. This is a novel symmetry relating bosons (normally force-carrying particles) and fermions (which normally feel the forces). In supersymmetry, bosons could have fermion counterparts, and vice versa. Although this subject is still largely a theorist's playground, many of the particles and phenomena predicted by models of low energy supersymmetry now seem within reach of present and planned future accelerator experiments, and this was one of the main reasons for choosing a more speculative theme after more phenomenological orientations in recent DESY Theory Workshops. After the welcome by DESY Director General Bjorn Wiik, attention was immediately focused on experimental aspects. P. Steffen (DESY) presented the latest results from HERA. In the following talks, K. Honscheid (Ohio), S. Lammel (Fermilab) and S. Komamiya (CERN and Tokyo) reviewed the experimental situation at electron-proton, hadron and electron-positron colliders, respectively. They discussed the most recent limits for supersymmetric particles (still none in sight!), as well as precision experiments where deviations from the standard model might show up. The workshop was treated to a first rate introduction to the MSSM (''minimal supersymmetric standard model'') by F. Zwirner (CERN), who clearly explained the motivation for going supersymmetric and reviewed the basic structure of the MSSM, its particle content and couplings, as well as the soft breaking terms necessary to avoid immediate conflict with experiment. This was followed by a systematic discussion of the Higgs sector by H. Haber (Santa Cruz), where the first hints of new physics could appear. However, he also made clear that it may not be easy to distinguish standard and non-standard Higgs bosons. Symmetries beyond the standard model, and in particular supersymmetric grand unification were treated in detail by G. Ross (Oxford) and S

  3. Superstrings and the search for the theory of everything

    International Nuclear Information System (INIS)

    Peat, D.

    1988-01-01

    This book contains the following chapters: A Crisis in Physics; From Points to Strings; Nambu's String Theory; Grand Unification; Superstrings; Heterotic Strings: Two Dimensions in One; From Spinors to Twistors; Twistor Space; Twistor Gravity; and Into Deep Waters

  4. Prospects for further unification

    International Nuclear Information System (INIS)

    Ne'eman, Y.

    1983-07-01

    We review the unification of weak and electromagnetic interactions (QAD), the prevalent color gauge theory of the strong interactions (QCD) and attempts to embed both these theories in a further Unified Gauge Theory. We discuss the related advances in cosmology and touch upon other approaches to the understanding of particles and fields. 44 references

  5. Low-energy parity restoration and unification mass scale within maximal symmetries

    Directory of Open Access Journals (Sweden)

    Ajaya K. Mohanty

    1984-01-01

    Full Text Available We investigate the hierarchy of gauge boson masses in the maximal grand unified theory by studying the renormalization group equations for the running coupling constants associated with the symmetry breaking of SU(16viaSU(12 q×SU(4 l×U(1 |B|−|L| chain. Particular attention is given to the contribution of Higgs scalars to these equations. It is found that the intermediate mass scale ML, associated with right-handed gauge bosons could be as low as 10 3 GeV only for sin 2θ w(M L as high as 0.265 with α s(M L=0.13. In this chain of symmetry breaking, we have also examined the lowest unification mass that is allowed by the low-energy data for sin 2θ w(M L and the assumed gauge hierarchy. This has been done in two cases; first for the case where SU(3 c is vectorial, second, for the case where SU(3 c is axial. In both cases the lowest unification mass scales were found to be 10 13, 10 11, 10 8 and 10 7 GeV for sin 2θ w(M L = 0.22, 0.24, 0.26,and0.265 respectively with α s(M L = 0.13. The implication of these low unification masses on baryon non-conserving processes is also discussed.

  6. Higher-derivative Lee-Wick unification

    International Nuclear Information System (INIS)

    Carone, Christopher D.

    2009-01-01

    We consider gauge coupling unification in Lee-Wick extensions of the Standard Model that include higher-derivative quadratic terms beyond the minimally required set. We determine how the beta functions are modified when some Standard Model particles have two Lee-Wick partners. We show that gauge coupling unification can be achieved in such models without requiring the introduction of additional fields in the higher-derivative theory and we comment on possible ultraviolet completions.

  7. Unification and geometrization of physics in the cosmological context

    International Nuclear Information System (INIS)

    Heller, M.; Watykanskie Obserwatorium Astronomiczne, Vatican

    1991-01-01

    Einstein belived that a good physical theory should posses an ''inner perfection''. Trace the inner perfection of the present gauge theories by contemplating their geometric structures (in terms of fibre bundles). The search for the ultimate symmetry of the unification of physics unavoidably leads to the unification of physics and cosmology. 4 figs., 23 refs. (author)

  8. Proceedings of the Johns Hopkins workshop on current problems in particle theory 5: unified field theories and beyond

    International Nuclear Information System (INIS)

    1981-01-01

    Topics covered include: symmetric gauge theories; infinite lie algebras in physics; the mechanism for confinement in massive quark QCD; a search for possible composite models of quarks and leptons; the radiative structure of Fermion masses; fractional electric charge in QCD; heavy particle effects; Fermion mass heirarchies in theories of technicolor; statistical notions applied in the early universe; grand unification and cosmology - an environmental impact statement; first order phase transition in the early universe; the electric dipole moment of the neutron; cosmological constraints on Grand Unified Theories; and the consequences for CP invariance of instanton angles THETA in dynamically broken gauge theories. Individual items from this workshop were prepared separately for the data base

  9. Proceedings of the Johns Hopkins workshop on current problems in particle theory 5: unified field theories and beyond

    Energy Technology Data Exchange (ETDEWEB)

    1981-01-01

    Topics covered include: symmetric gauge theories; infinite lie algebras in physics; the mechanism for confinement in massive quark QCD; a search for possible composite models of quarks and leptons; the radiative structure of Fermion masses; fractional electric charge in QCD; heavy particle effects; Fermion mass heirarchies in theories of technicolor; statistical notions applied in the early universe; grand unification and cosmology - an environmental impact statement; first order phase transition in the early universe; the electric dipole moment of the neutron; cosmological constraints on Grand Unified Theories; and the consequences for CP invariance of instanton angles THETA in dynamically broken gauge theories. Individual items from this workshop were prepared separately for the data base. (GHT)

  10. Proton decay in grand unified theories

    International Nuclear Information System (INIS)

    Lucha, W.

    1984-01-01

    Interactions which violate the conservation of baryon and lepton number represent an intrinsic part of all grand unified theories (GUTs) of strong and electroweak interactions. These new interactions - predicted within the framework of GUTs - generate B and L violating four-fermion interactions via the exchange of superheavy particles which cannot be ascribed a well-defined baryon or lepton number. The effective coupling constant of these four-fermion interactions might be large enough to make the proton decay detectable by the present generation of experiments. In this review the basic concepts of conventional as well as supersymmetric GUTs relevant for proton decay are sketched. The baryon number violating sector of grand unified theories is discussed in more detail. Special emphasis is laid on the various selection rules arising as consequences of low-energy gauge invariance and supersymmetry for proton decay. These selection rules already determine the coarse pattern of the resulting decay modes and branching ratios without any reference to or detailed knowledge of the underlying grand unified theory. Finally the numerous theoretical predictions are summarized and confronted with experiment. (Author)

  11. Psychotherapy Integration via Theoretical Unification

    Directory of Open Access Journals (Sweden)

    Warren W. Tryon

    2017-01-01

    Full Text Available Meaningful psychotherapy integration requires theoretical unification because psychotherapists can only be expected to treat patients with the same diagnoses similarly if they understand these disorders similarly and if they agree on the mechanisms by which effective treatments work. Tryon (in press has proposed a transtheoretic transdiagnostic psychotherapy based on an Applied Psychological Science (APS clinical orientation, founded on a BioPsychology Network explanatory system that provides sufficient theoretical unification to support meaningful psychotherapy integration. That proposal focused mainly on making a neuroscience argument. This article makes a different argument for theoretical unification and consequently psychotherapy integration. The strength of theories of psychotherapy, like all theory, is to focus on certain topics, goals, and methods. But this strength is also a weakness because it can blind one to alternative perspectives and thereby promote unnecessary competition among therapies. This article provides a broader perspective based on learning and memory that is consistent with the behavioral, cognitive, cognitive-behavioral, psychodynamic, pharmacologic, and Existential/Humanistic/Experiential clinical orientations. It thereby provides a basis for meaningful psychotherapy integration.

  12. Gauge theories

    International Nuclear Information System (INIS)

    Jarlskog, C.

    An introduction to the unified gauge theories of weak and electromagnetic interactions is given. The ingredients of gauge theories and symmetries and conservation laws lead to discussion of local gauge invariance and QED, followed by weak interactions and quantum flavor dynamics. The construction of the standard SU(2)xU(1) model precedes discussion of the unification of weak and electromagnetic interactions and weak neutral current couplings in this model. Presentation of spontaneous symmetry breaking and spontaneous breaking of a local symmetry leads to a spontaneous breaking scheme for the standard SU(2)xU(1) model. Consideration of quarks, leptons, masses and the Cabibbo angles, of the four quark and six quark models and CP violation lead finally to grand unification, followed by discussion of mixing angles in the Georgi-Glashow model, the Higgses of the SU(5) model and proton/ neutron decay in SU(5). (JIW)

  13. Grand unification and subcritical hybrid inflation

    International Nuclear Information System (INIS)

    Buchmueller, Wilfried; Ishiwata, Koji

    2014-12-01

    We consider hybrid inflation for small couplings of the inflaton to matter such that the critical value of the inflaton field exceeds the Planck mass. It has recently been shown that inflation then continues at subcritical inflaton field values where quantum fluctuations generate an effective inflaton mass. The effective inflaton potential interpolates between a quadratic potential at small field values and a plateau at large field values. An analysis of the allowed parameter space leads to predictions for the scalar spectral index n s and the tensor-to-scalar ratio r similar to those of natural inflation. Using the range for n s and r favoured by the Planck data, we find that the energy scale of the plateau is constrained to the interval (1.6-2.4) x 10 16 GeV which includes the energy scale of gauge coupling unification in the supersymmetric standard model. The tensor-to-scalar ratio is predicted to have the lower bound r>0.049 for 60 e-folds before the end of inflation.

  14. Unification of gauge and gravity Chern-Simons theories in 3-D space-time

    Energy Technology Data Exchange (ETDEWEB)

    Saghir, Chireen A.; Shamseddine, Laurence W. [American University of Beirut, Physics Department, Beirut (Lebanon)

    2017-11-15

    Chamseddine and Mukhanov showed that gravity and gauge theories could be unified in one geometric construction provided that a metricity condition is imposed on the vielbein. In this paper we are going to show that by enlarging the gauge group we are able to unify Chern-Simons gauge theory and Chern-Simons gravity in 3-D space-time. Such a unification leads to the quantization of the coefficients for both Chern-Simons terms for compact groups but not for non-compact groups. Moreover, it leads to a topological invariant quantity of the 3-dimensional space-time manifold on which they are defined. (orig.)

  15. Logarithmic unification from symmetries enhanced in the sub-millimeter infrared

    International Nuclear Information System (INIS)

    Arkani-Hamed, Nima; Dimopoulos, Savas; March-Russell, John

    1999-01-01

    In theories with TeV string scale and sub-millimeter extra dimensions the attractive picture of logarithmic gauge coupling unification at 10 16 GeV is seemingly destroyed. In this paper we argue to the contrary that logarithmic unification can occur in such theories. The rationale for unification is no longer that a gauge symmetry is restored at short distances, but rather that a geometric symmetry is restored at large distances in the bulk away from our 3-brane. The apparent ''running'' of the gauge couplings to energies far above the string scale actually arises from the logarithmic variation of classical fields in (sets of) two large transverse dimensions. We present a number of N = 2 and N = 1 supersymmetric D-brane constructions illustrating this picture for unification

  16. Proceedings of the 8 Warsaw symposium on elementary particle physics, Kazimierz, Poland, May 26 - June 1, 1985

    International Nuclear Information System (INIS)

    Ajduk, Z.

    1985-01-01

    These proceedings contain 47 lectures held at the symposium. They deal with pbar-p collider results, phenomenology of electroweak effects, high energy lepton interactions, high energy hadron interactions, quantum chromodynamics, bag model, grand unification, supersymmetry and superstring theory. (M.F.W.)

  17. Einstein's dream : the space-time unification of fundamental forces

    Energy Technology Data Exchange (ETDEWEB)

    Salam, A [International Centre for Theoretical Physics, Trieste (Italy)

    1981-06-01

    The historical developments in physics which started with Galileo in the 11th century, Newton in the 17 century, culminated in the unification of space-time by Einstein in this century are traced. The theories put forward by Einstein himself and by subsequent workers in the field after him, regarding the unification of all basic forces of nature (i.e.) the electromagnetic and the gravitational ones and the weak and strong nuclear forces are discussed. The experiments being conducted in Kolar and other places to detect a heavier photon which would be a positive proof of the validity of the unification theory, are touched upon. The possible application of this concept even in industry has been pointed out.

  18. Quantum numbers of anti-grand-unified-theory Higgs fields from the quark-lepton spectrum

    International Nuclear Information System (INIS)

    Froggatt, C.D.; Nielsen, H.B.; Smith, D.J.

    2002-01-01

    A series of Higgs field quantum numbers in the anti-grand-unification model, based on the gauge group SMG 3 xU(1) f , is tested against the spectrum of quark and lepton masses and mixing angles. A more precise formulation of the statement that the couplings are assumed of order unity is given. It is found that the corrections coming from this more precise assumption do not contain factors of the order of the number of colors, N c =3, as one could have feared. We also include a combinatorial correction factor, taking account of the distinct internal orderings within the chain Feynman diagrams in our statistical estimates. Strictly speaking our model predicts that the uncertainty in its predictions and thus the accuracy of our fits should be ±60%. Many of the best fitting quantum numbers give a higher accuracy fit to the masses and mixing angles, although within the expected fluctuations in a χ 2 . This means that our fit is as good as it can possibly be

  19. Fundamental Elements and Interactions of Nature: A Classical Unification Theory

    Directory of Open Access Journals (Sweden)

    Tianxi Zhang

    2010-04-01

    Full Text Available A classical unification theory that completely unifies all the fundamental interactions of nature is developed. First, the nature is suggested to be composed of the following four fundamental elements: mass, radiation, electric charge, and color charge. All known types of matter or particles are a combination of one or more of the four fundamental elements. Photons are radiation; neutrons have only mass; protons have both mass and electric charge; and quarks contain mass, electric charge, and color charge. The nature fundamental interactions are interactions among these nature fundamental elements. Mass and radiation are two forms of real energy. Electric and color charges are considered as two forms of imaginary energy. All the fundamental interactions of nature are therefore unified as a single interaction between complex energies. The interaction between real energies is the gravitational force, which has three types: mass-mass, mass-radiation, and radiation-radiation interactions. Calculating the work done by the mass-radiation interaction on a photon derives the Einsteinian gravitational redshift. Calculating the work done on a photon by the radiation-radiation interaction derives a radiation redshift, which is much smaller than the gravitational redshift. The interaction between imaginary energies is the electromagnetic (between electric charges, weak (between electric and color charges, and strong (between color charges interactions. In addition, we have four imaginary forces between real and imaginary energies, which are mass-electric charge, radiation-electric charge, mass-color charge, and radiation-color charge interactions. Among the four fundamental elements, there are ten (six real and four imaginary fundamental interactions. This classical unification theory deepens our understanding of the nature fundamental elements and interactions, develops a new concept of imaginary energy for electric and color charges, and provides a

  20. Fundamental Elements and Interactions of Nature: A Classical Unification Theory

    Directory of Open Access Journals (Sweden)

    Zhang T. X.

    2010-04-01

    Full Text Available A classical unification theory that completely unifies all the fundamental interactions of nature is developed. First, the nature is suggested to be composed of the following four fundamental elements: mass, radiation, electric charge, and color charge. All known types of matter or particles are a combination of one or more of the four fundamental elements. Photons are radiation; neutrons have only mass; protons have both mass and electric charge; and quarks contain mass, electric charge, and color charge. The nature fundamental interactions are interactions among these nature fundamental elements. Mass and radiation are two forms of real energy. Electric and color charges are con- sidered as two forms of imaginary energy. All the fundamental interactions of nature are therefore unified as a single interaction between complex energies. The interac- tion between real energies is the gravitational force, which has three types: mass-mass, mass-radiation, and radiation-radiation interactions. Calculating the work done by the mass-radiation interaction on a photon derives the Einsteinian gravitational redshift. Calculating the work done on a photon by the radiation-radiation interaction derives a radiation redshift, which is much smaller than the gravitational redshift. The interaction between imaginary energies is the electromagnetic (between electric charges, weak (between electric and color charges, and strong (between color charges interactions. In addition, we have four imaginary forces between real and imaginary energies, which are mass-electric charge, radiation-electric charge, mass-color charge, and radiation- color charge interactions. Among the four fundamental elements, there are ten (six real and four imaginary fundamental interactions. This classical unification theory deep- ens our understanding of the nature fundamental elements and interactions, develops a new concept of imaginary energy for electric and color charges, and provides a

  1. Liberating methodological thinking in human sciences from grand theories

    DEFF Research Database (Denmark)

    Kharlamov, Nikita; Baldursson, Einar Baldvin

    2016-01-01

    focus on the necessity of a “grand unified theory” at the expense of any and all alternative perspectives. Properties of grand theories are discussed on the examples of Giddens and Bourdieu. It is argued that grand theories hamper a more productive focus on concrete phenomena. Robert Merton’s focus......Many humanistic and social disciplines are naturally inclined to seek for human-, person-, self- centered focus, and develop a holistic theory of such. Such disciplines continually engage with philosophical, metaphysical and meta-theoretical perspectives. This engagement often leads to a singular...... on “middle range” theories is revisited and its continuing relevance is highlighted. The level of abstraction characteristic of such theories, as well as the way they engage with the empirical social reality, are discussed. The article concludes by considering the paradoxical reductionism that can...

  2. Simple unification

    International Nuclear Information System (INIS)

    Ponce, W.A.; Zepeda, A.

    1987-08-01

    We present the results obtained from our systematic search of a simple Lie group that unifies weak and electromagnetic interactions in a single truly unified theory. We work with fractionally charged quarks, and allow for particles and antiparticles to belong to the same irreducible representation. We found that models based on SU(6), SU(7), SU(8) and SU(10) are viable candidates for simple unification. (author). 23 refs

  3. Constructing 5d orbifold grand unified theories from heterotic strings

    International Nuclear Information System (INIS)

    Kobayashi, Tatsuo; Raby, Stuart; Zhang Renjie

    2004-01-01

    A three-generation Pati-Salam model is constructed by compactifying the heterotic string on a particular T 6 /Z 6 Abelian symmetric orbifold with two discrete Wilson lines. The compactified space is taken to be the Lie algebra lattice G 2 -bar SU(3)-bar SO(4). When one dimension of the SO(4) lattice is large compared to the string scale, this model reproduces many features of a 5d SO(10) grand unified theory compactified on an S 1 /Z 2 orbifold. (Of course, with two large extra dimensions we can obtain a 6d SO(10) grand unified theory.) We identify the orbifold parities and other ingredients of the orbifold grand unified theories in the string model. Our construction provides a UV completion of orbifold grand unified theories, and gives new insights into both field theoretical and string theoretical constructions

  4. On the GUT scale of F-theory SU(5)

    International Nuclear Information System (INIS)

    Leontaris, G.K.; Vlachos, N.D.

    2011-01-01

    In F-theory GUTs, threshold corrections from Kaluza-Klein (KK) massive modes arising from gauge and matter multiplets play an important role in the determination of the weak mixing angle and the strong gauge coupling of the effective low energy model. In this Letter we further explore the induced modifications on the gauge couplings running and the GUT scale. In particular, we focus on the KK-contributions from matter curves and analyze the conditions on the chiral and Higgs matter spectrum which imply a GUT scale consistent with the minimal unification scenario. As an application, we present an explicit computation of these thresholds for matter fields residing on specific non-trivial Riemann surfaces.

  5. Status of the superworld from theory to experiment

    International Nuclear Information System (INIS)

    Lopez, J.L.; Nanopoulos, D.V.; Zichichi, A.

    1994-01-01

    Among the most outstanding conceptual developments in particle physics we have: the unification of all particle interactions at very-high energies (Grand Unification), the fermion-boson symmetry (Supersymmetry), the non-point-like structure of elementary particles (String theory), and the understanding that all dynamical quantities (gauge couplings, masses, Yukawa coupling) run with energy (Renormalization Group Equations). The goal is to make use of these great developments to construct a theory which embraces all fundamental forces of Nature, including gravity. In this review we address this problem and its possible implications for physics in the energy range where our experimental facilities operate. We show that what is required are not qualitative arguments but a set of detailed calculations with definite predictions. (Author)

  6. Aspects of extra dimensional supersymmetric unified theories

    International Nuclear Information System (INIS)

    Fichet, S.

    2011-09-01

    The purpose of this work is to investigate Grand Unified Theories (GUTs) and to make the link with passed and upcoming experiments. The structure of this thesis is as follows. In the first chapter, we will briefly review the sequence of arguments leading to the Higgs mechanism, then to the different concepts underlying physics beyond the Standard Model, and to the paradigm of extra dimensional supersymmetric grand unified theories. At each level of the argumentation, we will mention the different solutions available. The second chapter introduces more formally supersymmetry and extra dimensions, focusing in particular on the aspects of symmetry breaking. Then, in the third chapter, we present in details the two frameworks of extra dimensional theories in which we worked, called supersymmetric gauge-Higgs unification (GHU) and holographic grand unification (HGU) as well as the developments and modifications we brought to them. The fourth chapter is devoted to the low energy viability of the GHU framework, as well as its phenomenological implications. The fifth chapter presents a more generic study of the property of GUT-scale degenerate Higgs mass matrix, common to both frameworks. Finally, the sixth chapter is devoted to the viability and phenomenological implications of the HGU framework, with special emphasis on lepton flavour violation. This quantitative study takes properly into account effects of matrix anarchy, as well as exact flavour observables. The results obtained should generalize, at least qualitatively, to any other model with similar localization and supersymmetry breaking features

  7. Probes of Yukawa unification in supersymmetric SO(10) models

    Energy Technology Data Exchange (ETDEWEB)

    Westhoff, Susanne

    2009-10-23

    This work is composed as follows: In Chapter 1, the disposed reader is made familiar with the foundations of flavourphysics and Grand Unification, including group-theoretical aspects of SO(10). In Chapter 2, we introduce a specific supersymmetric GUT model based on SO(10) and designed to probe down-quark-lepton Yukawa unification. Within this framework we explore the effects of large atmospheric neutrino mixing in bottom-strange transitions on the mass difference and CP phase in B{sub s}- anti B{sub s} meson mixing. Chapter 3 is devoted to corrections to Yukawa unification. We derive constraints on Yukawa corrections for light fermions from K- anti K and B{sub d}- anti B {sub d} mixing. As an application we study implications of neutrino mixing effects in CP-violating K and B{sub d} observables on the unitrity triangle. Finally, in Chapter 4, we discuss effects of large tan {beta} in B{yields}(D){tau}{nu} decays with respect to their potential to discover charged Higgs bosons and to discriminate between different GUT models of flavour.

  8. Gauge unification of fundamental forces

    International Nuclear Information System (INIS)

    Salam, A.

    1980-02-01

    After having reviewed briefly the last twenty years' progress in the theory of unification, with the twin aspects of development of a gauge theory of basic interactions linked with internal symmetry and the spontaneous breaking of these symmetries, the Nobel prize winners have summarized the present situation and the immediate problems. At the end, an extrapolation of the future is also given

  9. Precision LEP data, supersymmetric GUTs and string unification

    International Nuclear Information System (INIS)

    Ellis, J.; Kelley, S.; Nanopoulos, D.V.; Houston Area Research Center

    1990-01-01

    The precision of sin 2 θ w MS (m Z ) extracted from LEP data (0.233±0.001) confirms the prediction of minimal supersymmetric GUTs (0.235±0.004) within the errors of about 2%. Moreover, supersymmetric GUTs with three generations and a heavy top quark also predict m b =5.2±0.3 GeV in perfect agreement with potential model estimates (5.0±0.2 GeV). String unification would require that the effective grand unification scale m GUT be no larger than the effective string unification scale m SU , which is indeed consistent with the LEP data, which indicate m GUT ≅ 2x10 16 GeV in a minimal supersymmetric GUT, compared with the theoretical estimate m SU ≅ 10 17 GeV. Specific choices of the string model moduli could enforce m GUT =m SU even in minimal supersymmetric GUTs, whilst non-minimal supersymmetric GUTs can reconcile the successful predictions of sin 2 θ w with m GUT = m SU for generic values of the moduli, but tend to have m b too large. (orig.)

  10. Some consequences of embedding heavy color in grand unified theories

    International Nuclear Information System (INIS)

    Elias, V.

    1980-01-01

    I show that ''standard'' embedding constraints cannot accommodate an empirically motivated value for the heavy-color (HC) momentum scale Λ/sub HC/ if the heavy-color group is SU(N>3). The heavy-color group can be SU(3), provided such constraints are relaxed in order to allow fermions to contribute differentially to SU(3)/sub HC/ and SU(3)/sub QCD/ β-functions (QCD=quantum chromodynamics). Theories successfully embedding G/sub HC/>SU(3) along with the known interactions are shown to require vastly reduced unification mass scales. As an example, empirically acceptable values for Λ/sub HC/, sin 2 theta/sub W/, and α/sub s/(m/sub W/) as well as a unification mass scale within an order of magnitude of Λ/sub HC/ are accommodated within very large models based on [SU(2n)] 4 unifying symmetry

  11. Monodromies, fluxes, and compact three-generation F-theory GUTs

    International Nuclear Information System (INIS)

    Marsano, Joseph; Saulina, Natalia; Schaefer-Nameki, Sakura

    2009-01-01

    We analyze constraints for embedding local SU(5) F-theory GUTs into consistent compactifications and construct explicit three-generation models based on the geometry of [1]. The key tool for studying constraints in this problem when there is an underlying E 8 structure is the spectral cover, which encodes all of the symmetries that fix the allowed couplings in the superpotential, as well as the consistent, supersymmetric G-fluxes. Imposing phenomenological requirements such as the existence of three generations, top and bottom Yukawa couplings, good flavor structure and absence of exotics and of a tree-level μ-term, we derive stringent constraints on the allowed spectral covers. The resulting spectral covers are in conflict with the neutrino scenarios that have been studied in local F-theory models unless we allow for the possibility of additional charged fields, perhaps playing the role of gauge messengers, that do not comprise complete GUT multiplets. Quite remarkably, the existence of additional incomplete GUT multiplets below the GUT scale is necessary for consistency with gauge coupling 'unification', as their effect can precisely cancel that of the internal hypercharge flux, which distorts the gauge couplings already at M GUT .

  12. Restrictions on SU(5) as a grand unified theory

    International Nuclear Information System (INIS)

    Shellard, R.C.

    1984-01-01

    Some restrictions imposed upon Grand Unified Theories by dynamical symetry breakdown are examined. They are shown that, in particular, theories SU(5) as symmetry group, with 3 or more fermion families undergo dynamical symmetry breakdown, and some of the fermions will acquire mass at the Grand Unified scale. On the other hand, the SO(10) group, with 3 families is free from this problem. (Author) [pt

  13. Macroscopic constraints on string unification

    International Nuclear Information System (INIS)

    Taylor, T.R.

    1989-03-01

    The comparison of sting theory with experiment requires a huge extrapolation from the microscopic distances, of order of the Planck length, up to the macroscopic laboratory distances. The quantum effects give rise to large corrections to the macroscopic predictions of sting unification. I discus the model-independent constraints on the gravitational sector of string theory due to the inevitable existence of universal Fradkin-Tseytlin dilatons. 9 refs

  14. Flipped SU(5)xU(1){sub X} models from F-theory

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Jing [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Li Tianjun, E-mail: tjli@physics.rutgers.ed [George P. and Cynthia W. Mitchell Institute for Fundamental Physics, Texas A and M University, College Station, TX 77843 (United States); Key Laboratory of Frontiers in Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190 (China); Nanopoulos, Dimitri V. [George P. and Cynthia W. Mitchell Institute for Fundamental Physics, Texas A and M University, College Station, TX 77843 (United States); Astroparticle Physics Group, Houston Advanced Research Center (HARC), Mitchell Campus, Woodlands, TX 77381 (United States); Academy of Athens, Division of Natural Sciences, 28 Panepistimiou Avenue, Athens 10679 (Greece); Xie Dan [George P. and Cynthia W. Mitchell Institute for Fundamental Physics, Texas A and M University, College Station, TX 77843 (United States)

    2010-05-01

    We systematically construct flipped SU(5)xU(1){sub X} models without and with bulk vector-like particles from F-theory. To realize the decoupling scenario, we introduce sets of vector-like particles in complete SU(5)xU(1) multiplets at the TeV scale, or at the intermediate scale, or at the TeV scale and high scale. To avoid the Landau pole problem for the gauge couplings, we can only introduce five sets of vector-like particles around the TeV scale. These vector-like particles can couple to the Standard Model singlet fields, and obtain suitable masses by Higgs mechanism. We study gauge coupling unification in detail. We show that the U(1){sub X} flux contributions to the gauge couplings preserve the SU(5)xU(1){sub X} gauge coupling unification. We calculate the SU(3){sub C}xSU(2){sub L} unification scales, and the SU(5)xU(1){sub X} unification scales and unified couplings. In most of our models, the high-scale or bulk vector-like particles can be considered as string-scale threshold corrections since their masses are close to the string scale. Furthermore, we discuss the phenomenological consequences of our models. In particular, in the models with TeV-scale vector-like particles, the vector-like particles can be observed at the Large Hadron Collider, the proton decay is within the reach of the future Hyper-Kamiokande experiment, the lightest CP-even Higgs boson mass can be increased, the hybrid inflation can be naturally realized, and the correct cosmic primordial density fluctuations can be generated.

  15. Infrared fixed point solution for the top quark mass and unification of couplings in the MSSM

    International Nuclear Information System (INIS)

    Bardeen, W.A.; Carena, M.; Pokorski, S.; Wagner, C.E.M.

    1993-08-01

    We analyze the implications of the infrared quasi fixed point solution for the top quark mass in the Minimal Supersymmetric Standard Model. This solution could explain in a natural way the relatively large value of the top quark mass and, if confirmed experimentally, may be suggestive of the onset of nonperturbative physics at very high energy scales. In the framework of grand unification, the expected bottom quark -- tau lepton Yukawa coupling unification is very sensitive to the fixed point structure of the top quark mass. For the presently allowed values of the electroweak parameters and the bottom quark mass, the Yukawa coupling unification implies that the top quark mass must be within ten percent of its fixed point values

  16. The vacuum of the minimal nonsupersymmetric SO(10) unification

    International Nuclear Information System (INIS)

    Bertolini, Stefano; Di Luzio, Luca; Malinsky, Michal

    2010-01-01

    We study a class of nonsupersymmetric SO(10) grand-unified scenarios where the first stage of the symmetry breaking is driven by the vacuum expectation values of the 45-dimensional adjoint representation. Three-decade-old results claim that such a Higgs setting may lead exclusively to the flipped SU(5) x U(1) intermediate stage. We show that this conclusion is actually an artifact of the tree-level potential. The study of the accidental global symmetries emerging in various limits of the scalar potential offers a simple understanding of the tree-level result and a rationale for the drastic impact of quantum corrections. We scrutinize in detail the simplest and paradigmatic case of the 45 H +16 H Higgs sector triggering the breaking of SO(10) to the standard electroweak model. We show that the minimization of the one-loop effective potential allows for intermediate SU(4) C x SU(2) L x U(1) R and SU(3) c x SU(2) L x SU(2) R x U(1) B-L symmetric stages as well. These are the options favored by gauge unification. Our results, that apply whenever the SO(10) breaking is triggered by H >, open the path for hunting the simplest realistic scenario of nonsupersymmetric SO(10) grand unification.

  17. Vanishing corrections on intermediate scale and implications for unification of forces

    International Nuclear Information System (INIS)

    Parida, M.K.

    1996-02-01

    In two-step breakings of a class of grand unified theories including SO(10), we prove a theorem showing that the scale (M I ) where the Pati-Salam gauge symmetry with parity breaks down to the standard gauge group, has vanishing corrections due to all sources emerging from higher scales (μ > M I ) such as the one-loop and all higher-loop effects, the GUT-threshold, gravitational smearing, and string threshold effects. Implications of such a scale for the unification of gauge couplings with small Majorana neutrino masses are discussed. In string inspired SO(10), we show that M I ≅ 5 x 10 12 GeV, needed for neutrino masses, with the GUT scale M U ≅ M str can be realized provided certain particle states in the predicted spectrum are light. (author). 28 refs, 1 tab

  18. Gauge coupling unification and nonequilibrium thermal dark matter.

    Science.gov (United States)

    Mambrini, Yann; Olive, Keith A; Quevillon, Jérémie; Zaldívar, Bryan

    2013-06-14

    We study a new mechanism for the production of dark matter in the Universe which does not rely on thermal equilibrium. Dark matter is populated from the thermal bath subsequent to inflationary reheating via a massive mediator whose mass is above the reheating scale T(RH). To this end, we consider models with an extra U(1) gauge symmetry broken at some intermediate scale (M(int) ≃ 10(10)-10(12) GeV). We show that not only does the model allow for gauge coupling unification (at a higher scale associated with grand unification) but it can provide a dark matter candidate which is a standard model singlet but charged under the extra U(1). The intermediate scale gauge boson(s) which are predicted in several E6/SO(10) constructions can be a natural mediator between dark matter and the thermal bath. We show that the dark matter abundance, while never having achieved thermal equilibrium, is fixed shortly after the reheating epoch by the relation T(RH)(3)/M(int)(4). As a consequence, we show that the unification of gauge couplings which determines M(int) also fixes the reheating temperature, which can be as high as T(RH) ≃ 10(11) GeV.

  19. Technicolor and Beyond: Unification in Theory Space

    International Nuclear Information System (INIS)

    Sannino, Francesco

    2010-01-01

    I will briefly review the salient features of models of dynamical electroweak symmetry breaking together with the traditional extensions needed to provide masses to the standard model fermions in absence of fundamental scalars. The idea walking idea is introduced according to which one should carefully take into account the effects of the extended technicolor dynamics on the technicolor dynamics itself. The interplay between the four fermion interactions stemming from the extended technicolor interactions and the technicolor model can strongly enhance the anomalous dimension of the mass of the techniquarks allowing to decouple the Flavor Changing Neutral Currents problem from the one of the generation of the large top mass. I will also review the Minimal Walking Technicolor (MWT) models. In the second part of this review I consider the interesting possibility to marry supersymmetry and technicolor. The reason is to provide a unification of different extensions of the standard model. For example, this means that one can recover, according to the parameters and spectrum of the theory distinct extensions of the standard model, from supersymmetry to technicolor and unparticle physiscs. A surprising result is that a minimal (in terms of the smallest number of fields) supersymmetrization of the MWT model leads to the maximal supersymmetry in four dimensions, i.e. N = 4 SYM.

  20. Dark Matter after LHC Run I: Clues to Unification

    Directory of Open Access Journals (Sweden)

    Olive Keith A.

    2017-01-01

    Full Text Available After the results of Run I, can we still ‘guarantee’ the discovery of supersymmetry at the LHC? It is shown that viable dark matter models in CMSSM-like models tend to lie in strips (co-annihilation, funnel, focus point. The role of grand unification in constructing supersymmetric models is discussed and it is argued that non-supersymmetric GUTs such as SO(10 may provide solutions to many of the standard problems addressed by supersymmetry.

  1. From Minimal to Realistic Supersymmetric SU(5) Grand Unification

    CERN Document Server

    Altarelli, Guido; Masina, I; Altarelli, Guido; Feruglio, Ferruccio; Masina, Isabella

    2000-01-01

    We construct and discuss a "realistic" example of SUSY SU(5) GUT model, with an additional U(1) flavour symmetry, that is not plagued by the need of large fine tunings, like those associated with doublet-triplet splitting in the minimal model, and that leads to an acceptable phenomenology. This includes coupling unification with a value of alpha_s(m_Z) in much better agreement with the data than in the minimal version, an acceptable hierarchical pattern for fermion masses and mixing angles, also including neutrino masses and mixings, and a proton decay rate compatible with present limits (but the discovery of proton decay should be within reach of the next generation of experiments). In the neutrino sector the preferred solution is one with nearly maximal mixing both for atmospheric and solar neutrinos.

  2. [Theory of elementary particles studies in weak interaction and grand unification and studies in accelerator design

    International Nuclear Information System (INIS)

    1991-01-01

    This report discusses research in high energy physics on the following topics: rare b decays; flavor changing top decays;neutrino physics; standard model; cp violation; heavy ion collisions; electron-positron interactions; electron-hadron interactions; hadron-hadron interactions; deep inelastic scattering; and grand unified models

  3. Asymptotically Safe Grand Unification

    DEFF Research Database (Denmark)

    Bajc, Borut; Sannino, Francesco

    2016-01-01

    the inclusion of gravity, by generating an interacting ultraviolet fixed point, similar to the one recently discovered in non-supersymmetric gauge-Yukawa theories. Employing a-maximization, a-theorem, unitarity bounds, as well as positivity of other central charges we nonperturbatively rule out this possibility...

  4. Problems of CP-violation in early unification theories

    International Nuclear Information System (INIS)

    Liparteliani, A.G.; Monich, V.A.; Volkov, G.G.

    1985-01-01

    The present work studies possible mechanisms of P and CP-violation in the frames of an approach based on early unification of fundamental local symmetries, i.e., Pati-Salam four-colour symmetry, extended weak isotopic symmetry and that of quark-lepton generations. The work also studies the influence of generations mixing on the rates of rare processes in each of 3 classes of interactions

  5. The return of the King: No-Scale F-SU(5

    Directory of Open Access Journals (Sweden)

    Tianjun Li

    2017-01-01

    Full Text Available We revisit the viable parameter space in No-Scale F-SU(5, examining the Grand Unified Theory within the context of the prevailing gluino mass limits established by the LHC. The satisfaction of both the No-Scale boundary condition and the experimentally measured Standard Model (SM like Higgs boson mass requires a lower limit on the gluino mass in the model space of about 1.9 TeV, which maybe not coincidentally is the current LHC supersymmetry search bound. This offers a plausible explanation as to why a supersymmetry signal has thus far not been observed at the LHC. On the contrary, since the vector-like flippon particles are relatively heavy due to the strict condition that the supersymmetry breaking soft term Bμ must vanish at the unification scale, we also cannot address the recently vanished 750 GeV diphoton resonance at the 13 TeV LHC. Therefore, No-Scale F-SU(5 returns as a King after the spurious 750 GeV diphoton excess was gone with the wind.

  6. Introduction to Grand Unified Theories. 12

    International Nuclear Information System (INIS)

    Wali, K.C.

    1989-01-01

    This chapter presents an introduction into Grand Unified Theories. After a discussion of the general features to be expected in any such theory, and of the motivations for them, a detailed presentation of SU(5) theory is given. The group structures, particle multiplets, gauge and Higgs bosons are explained. The two stages of spontaneous symmetry breaking via the Higgs model, are calculated individually and in combination. Fermion mass matrices and relations between quark and lepton masses are derived. predictions of SU(5) theory, calculated using renormalization group methods, are derived. The chapter ends with discussions that bring together particle physics and cosmology, including the baryon asymmetry problem, phase transitions in the very early universe, and singularities like domain walls, vortex lines and monopoles. (author). 9 refs.; 4 figs.; 5 tabs

  7. Functional Pearls : Polytypic Unification

    NARCIS (Netherlands)

    Jansson, P.; Jeuring, J.T.

    1998-01-01

    Unification, or two-way pattern matching, is the process of solving an equation involving two first-order terms with variables. Unification is used in type inference in many programming languages and in the execution of logic programs. This means that unification algorithms have to be written over

  8. A new flavour imprint of SU(5-like grand unification and its LHC signatures

    Directory of Open Access Journals (Sweden)

    S. Fichet

    2015-03-01

    Full Text Available We point out that the hypothesis of an SU(5-like supersymmetric Grand Unified Theory (GUT implies a generic relation within the flavour structure of up-type squarks. Contrary to other well-known SU(5 relations between the down-quark and charged lepton sectors, this relation remains exact in the presence of any corrections and extra operators. Moreover it remains valid to a good precision at the electroweak scale, and opens thus new possibilities for testing SU(5-like GUTs. We derive the low-energy effective theory of observable light up-type squarks, that also constitutes a useful tool for squark phenomenology. We use this effective theory to determine how to test SU(5 relations at the LHC. Focusing on scenarios with light stops, compatible with Natural SUSY, it appears that simple tests involving ratios of event rates are sufficient to test the hypothesis of an SU(5-like GUT theory. The techniques of charm-tagging and top-polarimetry are a crucial ingredient of these tests.

  9. Phenomenology with F-theory S U (5 )

    Science.gov (United States)

    Leontaris, George K.; Shafi, Qaisar

    2017-09-01

    We explore the low-energy phenomenology of an F-theory-based S U (5 ) model which, in addition to the known quarks and leptons, contains Standard Model (SM) singlets and vectorlike color triplets and S U (2 ) doublets. Depending on their masses and couplings, some of these new particles may be observed at the LHC and future colliders. We discuss the restrictions by Cabibbo-Kobayashi-Maskawa matrix constraints on their mixing with the ordinary down quarks of the three chiral families. The model is consistent with gauge coupling unification at the usual supersymmetric GUT scale; dimension-five proton decay is adequately suppressed, while dimension-six decay mediated by the superheavy gauge bosons is enhanced by a factor of 5-7. The third generation charged fermion Yukawa couplings yield the corresponding low-energy masses in reasonable agreement with observations. The hierarchical nature of the masses of lighter generations is accounted for via nonrenormalizable interactions, with the perturbative vacuum expectation values (VEVs) of the SM singlet fields playing an essential role.

  10. Cosmological origin of the grand-unification mass scale

    International Nuclear Information System (INIS)

    Brout, R.; Englert, F.; Spindel, P.

    1979-01-01

    The origin of the universe as a quantum phenomenon leads to a self-consistently generated space-time structure in which the mass of the created particles is O (kappa/sup -1/2/). We interpret the origin of the universe as a phase transition in which the grand unified symmetry is spontaneously broken

  11. Possible test of grand unification in the double beta-decay

    International Nuclear Information System (INIS)

    Faessler, A.

    1988-01-01

    The more successful grand unified theories predict that the neutrino is identical with its antiparticle and therefore is a Majorana neutrino which violates lepton number conservation. Such a neutrino should have a finite mass and also a small right handed weak interaction. If the double neutrinoless beta decay is observed with the full decay energy in the two electrons, it would establish that the electron neutrino is a Majorana particle. It is shown that the relativistic corrections of the nucleonic wave functions are essential for determining an upper limit of the right handedness from the measured lower limit of the life-time against the neutrinoless double beta decay. The upper limit for the right handedness of the weak interaction derived from the lower limit of the life-times against the neutrinoless beta decay is vertical stroke vertical stroke -8 and the upper limit for the neutrino mass is vertical stroke ν m>vertical stroke + -decay in proton rich nuclei, one can explain the long standing puzzle of the quenching of the Gamow-Teller strength in agreement with the data. (orig.)

  12. Grand partition function in field theory with applications to sine-Gordon field theory

    International Nuclear Information System (INIS)

    Samuel, S.

    1978-01-01

    Certain relativistic field theories are shown to be equivalent to the grand partition function of an interacting gas. Using the physical insight given by this analogy many field-theoretic results are obtained, particularly for the sine-Gordon field theory. The main results are enumerated in the summary to which the reader is referred

  13. Grand canonical electronic density-functional theory: Algorithms and applications to electrochemistry

    International Nuclear Information System (INIS)

    Sundararaman, Ravishankar; Goddard, William A. III; Arias, Tomas A.

    2017-01-01

    First-principles calculations combining density-functional theory and continuum solvation models enable realistic theoretical modeling and design of electrochemical systems. When a reaction proceeds in such systems, the number of electrons in the portion of the system treated quantum mechanically changes continuously, with a balancing charge appearing in the continuum electrolyte. A grand-canonical ensemble of electrons at a chemical potential set by the electrode potential is therefore the ideal description of such systems that directly mimics the experimental condition. We present two distinct algorithms: a self-consistent field method and a direct variational free energy minimization method using auxiliary Hamiltonians (GC-AuxH), to solve the Kohn-Sham equations of electronic density-functional theory directly in the grand canonical ensemble at fixed potential. Both methods substantially improve performance compared to a sequence of conventional fixed-number calculations targeting the desired potential, with the GC-AuxH method additionally exhibiting reliable and smooth exponential convergence of the grand free energy. Lastly, we apply grand-canonical density-functional theory to the under-potential deposition of copper on platinum from chloride-containing electrolytes and show that chloride desorption, not partial copper monolayer formation, is responsible for the second voltammetric peak.

  14. Grand canonical electronic density-functional theory: Algorithms and applications to electrochemistry

    Science.gov (United States)

    Sundararaman, Ravishankar; Goddard, William A.; Arias, Tomas A.

    2017-03-01

    First-principles calculations combining density-functional theory and continuum solvation models enable realistic theoretical modeling and design of electrochemical systems. When a reaction proceeds in such systems, the number of electrons in the portion of the system treated quantum mechanically changes continuously, with a balancing charge appearing in the continuum electrolyte. A grand-canonical ensemble of electrons at a chemical potential set by the electrode potential is therefore the ideal description of such systems that directly mimics the experimental condition. We present two distinct algorithms: a self-consistent field method and a direct variational free energy minimization method using auxiliary Hamiltonians (GC-AuxH), to solve the Kohn-Sham equations of electronic density-functional theory directly in the grand canonical ensemble at fixed potential. Both methods substantially improve performance compared to a sequence of conventional fixed-number calculations targeting the desired potential, with the GC-AuxH method additionally exhibiting reliable and smooth exponential convergence of the grand free energy. Finally, we apply grand-canonical density-functional theory to the under-potential deposition of copper on platinum from chloride-containing electrolytes and show that chloride desorption, not partial copper monolayer formation, is responsible for the second voltammetric peak.

  15. Possibility of estimation of bare coupling of grand unification via theory of dispersion relations

    International Nuclear Information System (INIS)

    Perel'manl, C.

    2004-01-01

    Full Text:All processes of point particle elastic scatterings on the fixed point-like force center of any nature of coupling can be kinematically subdivided onto two classes: (proper) processes, at which complete energy throughout is not lesser kinetical one: E > If, and (improper) processes, at some interval of which potential energy become bigger complete energy (tunneling, backward scattering, etc.). The projector of proper processes, expressed via the Heaviside unit operator, P = θ(E - f), extracts from the general response functions (scattering amplitudes F) parts that describe all these processes: f (E, p, ...) = 9(E - E)F(E, p, ...). Its Fourier transformation leads to the dispersion relations in (t,r)-representation, which can be infinitely iterated and is represented in form of the Neumann series for the integral Fredholm equation. At this calculation the unique numerical constant α 0 = 2(2π) -5/2 ∼1/50 for (3+1) metrics is appeared, which does not depend from nature of coupling and therefore can be considered as the constant of decomposition of complete amplitude over number of interactions. Precisely this value, independent from dynamics, can be considered as the universal bare coupling. Via the Gell-Mann - Low relations it results in the GUT energy A-f = 10 18 GeV with consistent magnitudes of all running couplings and reasonable values of electron and nucleon masses as dynamical fields objects. Moreover it allows the consideration of some problems of black holes also

  16. Reintroducing the concept of force into relativity theory

    International Nuclear Information System (INIS)

    Mahajan, S.; Qadir, A.; Valanju, P.

    1979-07-01

    It is suggested that re-introducing forces into relativity theory may provide new insights and results. A look at the Kerr-Newmann geometry, and special cases of it, from this viewpoint indicates that there can be a short range repulsion in general. This repulsion suggests that naked singularities may be physically feasible. It is also found that there is a gravito-electric repulsion which would be important to consider in a grand unification scheme of strong, weak and electromagnetic forces. 8 references

  17. Reintroducing the concept of force into relativity theory

    Energy Technology Data Exchange (ETDEWEB)

    Mahajan, S.; Qadir, A.; Valanju, P.

    1979-07-01

    It is suggested that re-introducing forces into relativity theory may provide new insights and results. A look at the Kerr-Newmann geometry, and special cases of it, from this viewpoint indicates that there can be a short range repulsion in general. This repulsion suggests that naked singularities may be physically feasible. It is also found that there is a gravito-electric repulsion which would be important to consider in a grand unification scheme of strong, weak and electromagnetic forces. 8 references.

  18. Z2 vortex strings in grand unified theories

    International Nuclear Information System (INIS)

    Olive, D.; Turok, N.

    1982-01-01

    Spontaneously broken gauge theories may display distinct vortex string solutions for the disconnected components of the exact gauge symmetry group. A type of Higgs mechanism thought to apply in grand unified theories as being responsible for fermion masses yields Z 2 vortex lines, irrespectively of the group. These could seed galaxy formation if the corresponding fermion masses are superheavy. More generally a Higgs mechanism producing Zsub(n) vortex strings is presented. (orig.)

  19. Flavour Democracy in Strong Unification

    CERN Document Server

    Abel, S A; Abel, Steven; King, Steven

    1998-01-01

    We show that the fermion mass spectrum may naturally be understood in terms of flavour democratic fixed points in supersymmetric theories which have a large domain of attraction in the presence of "strong unification". Our approach provides an alternative to the approximate Yukawa texture zeroes of the Froggatt-Nielsen mechanism. We discuss a particular model based on a broken gauged $SU(3)_L\\times SU(3)_R$ family symmetry which illustrates our approach.

  20. Theory of weak interactions and related topics. Progress report, January 1-December 31, 1981

    International Nuclear Information System (INIS)

    Marshak, R.E.

    1985-08-01

    The research program demonstrated that the acceptance of B-L local symmetry as the weak hypercharge, whose spontaneous breakdown was connected to the spontaneous breakdown of parity, predicted a light electron neutrino (Majorana) and a related heavy neutrino. The prediction of neutron oscillations following from the PUT group SU(4)/sub C/ x SU(2)/sub L/ x SU(2)/sub R/ was scrutinized. A relation was derived between the mixing time for free neutron oscillations and the lifetime for nuclear stability with respect to ΔB = 2 transitions, and a study was conducted of the effect of time-varying or spatial-varying magnetic fields on the mixing time of neutron oscillations. Reasons are given for continuing work with the left-right symmetry (LRS) and partial unification theory (PUT) groups to their grand unification realization. It was shown that, without assuming a simple GUT group, that the color group has to be SU(3) and that the only possible GUT groups are SU(5) and SU(10). The gauge boson mass relation was derived for arbitrary Higgs structure associated either with the standard SU(2)/sub L/ x U(1) electroweak group or the LRS group. Also examined was the Pati-Salam type of grand unification. 31 refs

  1. Unification

    International Nuclear Information System (INIS)

    Iliopoulos, J.

    1983-01-01

    This chapter describes the weak and electromagnetic interactions by a gauge theory based on the group U(1)xSU(2). Discusses SO(10), E 6 , beyond gauge theories, Grassmann algebras, graded superalgebras, Majorana and Weyl spinors; particle representations; all possible supersymmetries of the S-matrix; representations in terms of fields; a simple field theory model; supersymmetry and gauge invariance; the breaking of supersymmetry; the supersymmetric extension of the standard model; and supersymmetry and grand-unified theories. Finds that the rate of approach to the symmetric, which is logarithmic for dimensionless couplings, is too slow to account for the high accuracy with which symmetries are observed in nature. Shows that scalar Q.E.D. in perturbation theory is not an I.R. attractor when one attempts to approach it via a class of theories with negative metric

  2. The toric SO(10) F-theory landscape

    International Nuclear Information System (INIS)

    Buchmuller, W.; Dierigl, M.; Oehlmann, P.K.; Ruehle, F.

    2017-09-01

    Supergravity theories in more than four dimensions with grand unified gauge symmetries are an important intermediate step towards the ultraviolet completion of the Standard Model in string theory. Using toric geometry, we classify and analyze six-dimensional F-theory vacua with gauge group SO(10) taking into account Mordell-Weil U(1) and discrete gauge factors. We determine the full matter spectrum of these models, including charged and neutral SO(10) singlets. Based solely on the geometry, we compute all matter multiplicities and confirm the cancellation of gauge and gravitational anomalies independent of the base space. Particular emphasis is put on symmetry enhancements at the loci of matter fields and to the frequent appearance of superconformal points. They are linked to non-toric Kaehler deformations which contribute to the counting of degrees of freedom. We compute the anomaly coefficients for these theories as well by using a base-independent blow-up procedure and superconformal matter transitions. Finally, we identify six-dimensional supergravity models which can yield the Standard Model with high-scale supersymmetry by further compactification to four dimensions in an Abelian flux background.

  3. The toric SO(10) F-theory landscape

    Energy Technology Data Exchange (ETDEWEB)

    Buchmuller, W.; Dierigl, M.; Oehlmann, P.K. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Ruehle, F. [Oxford Univ. (United Kingdom). Rudolf Peierls Centre for Theoretical Physics

    2017-09-15

    Supergravity theories in more than four dimensions with grand unified gauge symmetries are an important intermediate step towards the ultraviolet completion of the Standard Model in string theory. Using toric geometry, we classify and analyze six-dimensional F-theory vacua with gauge group SO(10) taking into account Mordell-Weil U(1) and discrete gauge factors. We determine the full matter spectrum of these models, including charged and neutral SO(10) singlets. Based solely on the geometry, we compute all matter multiplicities and confirm the cancellation of gauge and gravitational anomalies independent of the base space. Particular emphasis is put on symmetry enhancements at the loci of matter fields and to the frequent appearance of superconformal points. They are linked to non-toric Kaehler deformations which contribute to the counting of degrees of freedom. We compute the anomaly coefficients for these theories as well by using a base-independent blow-up procedure and superconformal matter transitions. Finally, we identify six-dimensional supergravity models which can yield the Standard Model with high-scale supersymmetry by further compactification to four dimensions in an Abelian flux background.

  4. F-theory, GUTs, and the weak scale

    International Nuclear Information System (INIS)

    Heckman, Jonathan J.; Vafa, Cumrun

    2009-01-01

    In this paper we study a deformation of gauge mediated supersymmetry breaking in a class of local F-theory GUT models where the scale of supersymmetry breaking determines the value of the μ term. Geometrically correlating these two scales constrains the soft SUSY breaking parameters of the MSSM. In this scenario, the hidden SUSY breaking sector involves an anomalous U(1) Peccei-Quinn symmetry which forbids bare μ and Bμ terms. This sector typically breaks supersymmetry at the desired range of energy scales through a simple stringy hybrid of a Fayet and Polonyi model. A variant of the Giudice-Masiero mechanism generates the value μ ∼ 10 2 -10 3 GeV when the hidden sector scale of supersymmetry breaking is F 1/2 ∼ 10 8.5 GeV. Further, the Bμ problem is solved due to the mild hierarchy between the GUT scale and Planck scale. These models relate SUSY breaking with the QCD axion, and solve the strong CP problem through an axion with decay constant f a ∼ M GUT cμ/Λ, where Λ ∼ 10 5 GeV is the characteristic scale of gaugino mass unification in gauge mediated models, and the ratio μ/Λ ∼ M GUT /M pl ∼ 10 -3 . We find f a ∼ 10 12 GeV, which is near the high end of the phenomenologically viable window. Here, the axino is the goldstino mode which is eaten by the gravitino. The gravitino is the LSP with a mass of about 10 1 -10 2 MeV, and a bino-like neutralino is (typically) the NLSP with mass of about 10 2 -10 3 GeV. Compatibility with electroweak symmetry breaking also determines the value of tanβ ∼ 30±7.

  5. Dark matter, mirror world, and E6 unification

    International Nuclear Information System (INIS)

    Das, Ch. R.; Laperashvili, L. V.

    2009-01-01

    The idea that the ordinary (O) and mirror (M) worlds exist simultaneously is developed. It is shown that, in the case of a violated mirror parity (MP), the renormalization-group evolution of the coupling constants, which is represented in the O world by the dependence α i -1 (μ) (μ is an energy variable), is not identical to the evolution of the coupling constants α' i -1 (μ) in the M world. Here, the index i labels the symmetry group under consideration, while a dash labels quantities defined in the M world. It is assumed that E 6 unification predicted by superstring theory restores MP at the unification scale M SGUT ∼ 10 18 GeV, this inevitably leading to the difference in the violation of E 6 unification in the O and M worlds at lower energies: E 6 → SO(10) x U(1) Z and E' 6 → SU(6)' x SU(2)' Z . Considering only asymptotically free theories, we present the evolution of all the inverse coupling constants α i -1 (μ) in the one-loop approximation. In dealing with the M world involving MP violation, we then arrive at the model of the accelerating expansion of our Universe, where the axion ('acceleron') belongs to the SU(2)' Z group of the M world. The coupling constant g' Z , which grows indefinitely at the scale Λ' Z ∼ 10 -3 eV, is associated with this group. Within this theory, our Universe is in the false vacuum of the M world, in agreement with the phenomenologically observed cosmological constant of about (3 x 10 -3 eV) 4 .

  6. Gauge coupling unification in six dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Lee, H.M. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)]|[Carnegie-Mellon Univ., Pittsburgh, PA (United States). Dept. of Physics

    2006-11-15

    We compute the one-loop gauge couplings in six-dimensional non-Abelian gauge theories on the T{sup 2}/Z{sub 2} orbifold with general GUT breaking boundary conditions. For concreteness, we apply the obtained general formulae to the gauge coupling running in a 6D SO(10) orbifold GUT where the GUT group is broken down to the standard model gauge group up to an extra U(1). We find that the one-loop corrections depend on the parity matrices encoding the orbifold boundary conditions as well as the volume and shape moduli of extra dimensions. When the U(1) is broken by the VEV of bulk singlets, the accompanying extra color triplets also affect the unification of the gauge couplings. In this case, the B-L breaking scale is closely linked to the compactification scales for maintaining a success of the gauge coupling unification. (orig.)

  7. Deductive Synthesis of the Unification Algorithm,

    Science.gov (United States)

    1981-06-01

    DEDUCTIVE SYNTHESIS OF THE I - UNIFICATION ALGORITHM Zohar Manna Richard Waldinger I F? Computer Science Department Artificial Intelligence Center...theorem proving," Artificial Intelligence Journal, Vol. 9, No. 1, pp. 1-35. Boyer, R. S. and J S. Moore [Jan. 19751, "Proving theorems about LISP...d’Intelligence Artificielle , U.E.R. de Luminy, Universit6 d’ Aix-Marseille II. Green, C. C. [May 1969], "Application of theorem proving to problem

  8. The GEM Theory of the Unification of Gravitation and Electro-Magnetism

    Science.gov (United States)

    Brandenburg, J. E.

    2012-01-01

    The GEM (Gravity Electro-Magnetism), theory is presented as an alloy of Sakharov and Kaluza-Klein approaches to field unification. GEM uses the concept of gravity fields as Poynting fields to postulate that the non-metric portion of the EM stress tensor becomes the metric tensor in strong fields leading to "self-censorship". Covariant formulation of the GEM theory is accomplished through definition of the spacetime metric tensor as a portion of the EM stress tensor normalized by its own trace: gab = 4(FcaFcb )/(FabFab), it is found that this results in a massless ground state vacuum and a Newtonian gravitation potential f=1/2 E2/B2 =GM/r , where E, B and F are part of the vacuum Zero Point Fluctuation (ZPF) and M and r are the mass and distance from the center of a gravitating body and G is the Newton gravitation constant. It is found that a Lorentz flat-space metric is recovered in the limit of a vacuum full spectrum ZPF. The vacuum ZPF energy and vacuum quantities G, h, c, gives birth to particles quantities mp, me, e,-e in a process triggered by the appearance of the Kaluza-Klein fifth dimension, where also the EM and gravity forces split from each other in a process correlated to the splitting apart of protons and electrons. The separate appearance of the proton and electron occurs as the splitting of a light-like spacetime interval of zero-length into a finite space-like portion containing three subdimensions identified with the quarks and a time-like portion identified with the electron. The separation of mass with charge for the electron and proton pair comes about from a U(1) symmetry with a rotation in imaginary angle. A logarithmic variation of charge with mass for the proton-electron pair results and leads to the formula ln(ro/rp) = s, where s = (mp/me)1/2 , where mp and me are the electron and proton masses respectively and where ro =e2/moc2 , and where mo = (mpme)1/2 and where rp is the Planck length . This leads to the formula G=e2/mo2aexp(-2s)=6

  9. Unification of SUSY breaking and GUT breaking

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Tatsuo [Department of Physics, Hokkaido University,Sapporo 060-0810 (Japan); Omura, Yuji [Department of Physics, Nagoya University,Nagoya 464-8602 (Japan)

    2015-02-18

    We build explicit supersymmetric unification models where grand unified gauge symmetry breaking and supersymmetry (SUSY) breaking are caused by the same sector. Besides, the SM-charged particles are also predicted by the symmetry breaking sector, and they give the soft SUSY breaking terms through the so-called gauge mediation. We investigate the mass spectrums in an explicit model with SU(5) and additional gauge groups, and discuss its phenomenological aspects. Especially, nonzero A-term and B-term are generated at one-loop level according to the mediation via the vector superfields, so that the electro-weak symmetry breaking and 125 GeV Higgs mass may be achieved by the large B-term and A-term even if the stop mass is around 1 TeV.

  10. Necessity of intermediate mass scales in grand unified theories with spontaneously broken CP invariance

    International Nuclear Information System (INIS)

    Senjanovic, G.

    1982-07-01

    It is demonstrated that the spontaneous breakdown of CP invariance in grand unified theories requires the presence of intermediate mass scales. The simplest realization is provided by weakly broken left-right symmetry in the context of SU(2)sub(L) x SU(2)sub(R) x U(1)sub(B-L) model embedded in grand unified theories. (author)

  11. Gauge unification of basic forces particularly of gravitation with strong interactions

    International Nuclear Information System (INIS)

    Salam, A.

    1977-01-01

    Corresponding to the two known types of gauge theories, Yang-Mills with spin-one mediating particles and Einstein Weyl with spin-two mediating particles, it is speculated that two distinct gauge unifications of the basic forces appear to be taking place. One is the familiar Yang-Mills unification of weak and electromagnetic forces with the strong. The second is the less familiar gauge unification of gravitation with spin-two tensor-dominated aspects of strong interactions. It is proposed that there are strongly interacting spin-two strong gravitons obeying Einstein's equations, and their existence gives a clue to an understanding of the (partial) confinement of quarks, as well as of the concept of hadronic temperature, through the use of Schwarzschild de-Sitter-like partially confining solitonic solutions of the strong gravity Einstein equation

  12. Isodual theory of antimatter applications to antigravity, grand unification and cosmology

    CERN Document Server

    Santilli, Ruggero Maria

    2006-01-01

    Antimatter, already conjectured by A. Schuster in 1898, was actually predicted by P.A.M. Dirac in the late 19-twenties in the negative-energy solutions of the Dirac equation. Its existence was subsequently confirmed via the Wilson chamber and became an established part of theoretical physics. Dirac soon discovered that particles with negative energy do not behave in a physically conventional manner, and he therefore developed his "hole theory". This restricted the study of antimatter to the sole level of second quantization. As a result antimatter created a scientific imbalance, because matter was treated at all levels of study, while antimatter was treated only at the level of second quantization. In search of a new mathematics for the resolution of this imbalance the author conceived what we know today as Santilli’s isodual mathematics, which permitted the construction of isodual classical mechanics, isodual quantization and isodual quantum mechanics. The scope of this monograph is to show that our classi...

  13. Quark-lepton unification and proton decay

    International Nuclear Information System (INIS)

    Pati, J.C.; Salam, A.

    1980-05-01

    Complexions for proton decay arising within a maximal symmetry for quark-lepton unification, which leads to spontaneous rather than intrinsic violations of B, L and F are considered. Four major modes satisfying δB=-1 and δF=0, -2, -4 and -6 are noted. It is stressed that some of these modes can coexist in accord with allowed solutions for renormalization group equations for coupling constants for a class of unifying symmetries. None of these remarks is dependent on the nature of quark charges. It is noted that if quarks and leptons are made of constituent preons, the preon binding is likely to be magnetic. (author)

  14. Model-based object classification using unification grammars and abstract representations

    Science.gov (United States)

    Liburdy, Kathleen A.; Schalkoff, Robert J.

    1993-04-01

    The design and implementation of a high level computer vision system which performs object classification is described. General object labelling and functional analysis require models of classes which display a wide range of geometric variations. A large representational gap exists between abstract criteria such as `graspable' and current geometric image descriptions. The vision system developed and described in this work addresses this problem and implements solutions based on a fusion of semantics, unification, and formal language theory. Object models are represented using unification grammars, which provide a framework for the integration of structure and semantics. A methodology for the derivation of symbolic image descriptions capable of interacting with the grammar-based models is described and implemented. A unification-based parser developed for this system achieves object classification by determining if the symbolic image description can be unified with the abstract criteria of an object model. Future research directions are indicated.

  15. Superforce the search for a grand unified theory of nature

    CERN Document Server

    Davies, Paul

    1985-01-01

    Many scientists believe we are on the verge of a "Theory of Everything" - a complete unification of all the fundamental forces and particles of nature. In this book, the physicist and author Paul Davies gives an account of the quest for a superforce that will explain how the physical universe is put together. The book describes the bewildering array of subatomic particles that have been discovered in recent years, and shows how their properties form abstract patterns and mathematical symmetries, hinting at deep linkages. It explains how the forces that act between these particles may require the existence of unseen extra dimensions of space, and why the latest bizarre theory suggests that the basic entities out of which all matter is built may not be particles at all, but strings. Aimed at the general reader, this account shows that a unified theory may be within our grasp, and that a single superforce may acmcount not only for the nature of matter, but even for the manner in which the universe came into exis...

  16. Rare B decays, rare τ decays, and grand unification

    International Nuclear Information System (INIS)

    Sher, M.; Yuan, Y.

    1991-01-01

    In multi-Higgs-boson extensions of the standard model, tree-level flavor-changing neutral currents exist naturally, unless suppressed by some symmetry. For a given rate, the exchanged scalar or pseudoscalar mass is very sensitive to the flavor-changing coupling between the first two generations. Since the Yukawa couplings of the first two generations are unknown and certainly very small, bounds which rely on some assumed value of this flavor-changing coupling are quite dubious. One might expect the size (and reliability) of the Yukawa couplings involving the third generation to be greater. In this paper, we consider processes involving τ's and B's, and determine the bounds on the flavor-changing couplings which involve third-generation fields. The strongest bound in the quark sector comes from B-bar B mixing and in the lepton sector, surprisingly, from μ→eγ. It is then noted that the flavor-changing couplings in the quark sector are related to those in the lepton sector in many grand unified theories, and one can ask whether an analysis of rare τ decays or rare B decays will provide the strongest constraints. We show that rare B decays provide the strongest bounds, and that no useful information can be obtained from rare τ decays. It is also noted that the most promising decay modes are B→Kμτ and B s →μτ, and we urge experimenters to look for rare decay modes of the B in which a τ is in the final state

  17. Unification and new particles at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Arkani-Hamed, Nima; D’Agnolo, Raffaele Tito; Low, Matthew [School of Natural Sciences, Institute for Advanced Study,Einstein Drive, Princeton, NJ 08540 (United States); Pinner, David [Princeton Center for Theoretical Physics, Princeton University,Jadwin Hall, Princeton, NJ 08544 (United States)

    2016-11-14

    Precision gauge coupling unification is one of the primary quantitative successes of low energy or split supersymmetry. Preserving this success puts severe restrictions on possible matter and gauge sectors that might appear at collider-accessible energies. In this work we enumerate new gauge sectors which are compatible with unification, consisting of horizontal gauge groups acting on vector-like matter charged under the Standard Model. Interestingly, almost all of these theories are in the supersymmetric conformal window at high energies and confine quickly after the superpartners are decoupled. For a range of scalar masses compatible with both moderately tuned and minimally split supersymmetry, the confining dynamics happen at the multi-TeV scale, leading to a spectrum of multiple spin-0 and spin-1 resonances accessible to the LHC, with unusual quantum numbers and striking decay patterns.

  18. Unification and new particles at the LHC

    International Nuclear Information System (INIS)

    Arkani-Hamed, Nima; D’Agnolo, Raffaele Tito; Low, Matthew; Pinner, David

    2016-01-01

    Precision gauge coupling unification is one of the primary quantitative successes of low energy or split supersymmetry. Preserving this success puts severe restrictions on possible matter and gauge sectors that might appear at collider-accessible energies. In this work we enumerate new gauge sectors which are compatible with unification, consisting of horizontal gauge groups acting on vector-like matter charged under the Standard Model. Interestingly, almost all of these theories are in the supersymmetric conformal window at high energies and confine quickly after the superpartners are decoupled. For a range of scalar masses compatible with both moderately tuned and minimally split supersymmetry, the confining dynamics happen at the multi-TeV scale, leading to a spectrum of multiple spin-0 and spin-1 resonances accessible to the LHC, with unusual quantum numbers and striking decay patterns.

  19. SAT Encoding of Unification in EL

    Science.gov (United States)

    Baader, Franz; Morawska, Barbara

    Unification in Description Logics has been proposed as a novel inference service that can, for example, be used to detect redundancies in ontologies. In a recent paper, we have shown that unification in EL is NP-complete, and thus of a complexity that is considerably lower than in other Description Logics of comparably restricted expressive power. In this paper, we introduce a new NP-algorithm for solving unification problems in EL, which is based on a reduction to satisfiability in propositional logic (SAT). The advantage of this new algorithm is, on the one hand, that it allows us to employ highly optimized state-of-the-art SAT solvers when implementing an EL-unification algorithm. On the other hand, this reduction provides us with a proof of the fact that EL-unification is in NP that is much simpler than the one given in our previous paper on EL-unification.

  20. Research program in elementary particle theory

    International Nuclear Information System (INIS)

    Balachandran, A.P.; Rosenzweig, C.; Schechter, J.; Wali, K.C.

    1990-01-01

    Discussed in this paper is a brief account of the research work of the principal investigators and their co-workers during the past few years. The topics covered include: Topology in Physics; Skyrme Model; High Temperature Superconductivity; fractional statistics, and generalized spin statistics theorem; QCD as a dual chromomagnetic superconductor; confinement and string picture in QCD; quark gluon plasmas; cosmic strings; effective Lagrangians for QCD; ''proton spin,'' ''strange content'' and related topics; physical basis of the Skyrme model; gauge theories and weak interactions; grand unification; Universal ''see saw mechanism''; abelian and non-abelian interactions of a test string

  1. Neutrino mixing in a grand unified theory

    International Nuclear Information System (INIS)

    Milton, K.; Tanaka, K.

    1980-01-01

    Neutrino mixing in a grand unified theory in which the neutrino mass matrix is determined by the Gell-Mann-Ramond-Slansky mechanism was investigated. With an arbitrary real right-handed Majorana mass matrix which incorporates three neutrino mass scales, the effects of the up-quark mass matrix are found to be dominant and as a result no significant mixing of ν/sub e/ occurs, while ν/sub μ/ - ν/sub γ/ mixing can be substantial

  2. Introduction to unification of electromagnetic and weak interactions

    International Nuclear Information System (INIS)

    Martin, F.

    1980-01-01

    After reviewing the present status of weak interaction phenomenology we discuss the basic principles of gauge theories. Then we show how Higgs mechanism can give massive quanta of interaction. The so-called 'Weinberg-Salam' model, which unifies electromagnetic and weak interactions, is described. We conclude with a few words on unification with strong interactions and gravity [fr

  3. Quantum field theory. How it is described, what holds the world together in the innermost; Quantenfeldtheorie. Wie man beschreibt, was die Welt im Innersten zusammenhaelt

    Energy Technology Data Exchange (ETDEWEB)

    Fritzsch, Harald [Muenchen Univ. (Germany). Physik Dept.

    2015-07-01

    Do we already know the ''theory for all'' or are we still far away from it? Does at highest energies really a ''Grand Unification'' of all fundamental forces exist? And which role do play the string theory and the Higgs boson? Harald Fritzsch takes the reader along with a mathematical journey through the world of quantum field theory and presents so a large survey about the most actual status of modern theoretical physics.

  4. SU(5) unification revisited

    International Nuclear Information System (INIS)

    Giveon, A.; Sarid, U.; Hall, L.J.; California Univ., Berkeley, CA

    1991-01-01

    Model-independent criteria for unification in the SU(5) framework are studied. These are applied to the minimal supersymmetric standard model and to the standard model with a split 45 Higgs representation. Although the former is consistent with SU(5) unification, the superpartner masses can vary over a wide range, and may even all lie well beyond the reach of planned colliders. Adding a split 45 to the standard model can also satisfy the unification criteria, so supersymmetric SU(5) is far from unique. Furthermore, we learn that separate Higgs doublets must couple to the top and bottom quarks in order to give a correct m b /m τ prediction. (orig.)

  5. Low-scale gaugino mass unification

    International Nuclear Information System (INIS)

    Endo, M.; Yoshioka, K.

    2008-04-01

    We present a new class of scenarios with the gaugino mass unification at the weak scale. The unification conditions are generally classified and then, the mirage gauge mediation is explored where gaugino masses are naturally unified and scalar partners of quarks and leptons have no mass hierarchy. The low-energy mass spectrum is governed by the mirage of unified gauge coupling which is seen by low-energy observers. We also study several explicit models for dynamically realizing the TeV-scale unification. (orig.)

  6. Low-scale gaugino mass unification

    Energy Technology Data Exchange (ETDEWEB)

    Endo, M [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Yoshioka, K [Kyoto Univ. (Japan). Dept. of Physics

    2008-04-15

    We present a new class of scenarios with the gaugino mass unification at the weak scale. The unification conditions are generally classified and then, the mirage gauge mediation is explored where gaugino masses are naturally unified and scalar partners of quarks and leptons have no mass hierarchy. The low-energy mass spectrum is governed by the mirage of unified gauge coupling which is seen by low-energy observers. We also study several explicit models for dynamically realizing the TeV-scale unification. (orig.)

  7. Unification of space-time and internal symmetries through superstrings, with elementary or composite quarks

    International Nuclear Information System (INIS)

    Huebsch, T.

    1987-01-01

    Symmetry properties of a given physical system constrain greatly the theoretical models built in the attempt to describe the system. In complement, the symmetry properties of a system typically undergo dramatic changes during its evolution in time, underpinning the concept of phase transitions. Employing these two ideas we analyze models of Particle Physics at increasingly higher levels of unification, attempting to cover the wide span from the domain of experimentally accessible energies to scales where all the known interactions (including gravity) may be described as low-energy effects of the tremendous and intricate structure of Superstring theories. In particular, we study the scenario of compactification of the Heterotic Superstring theory involving Calabi-Yau manifolds and derive the basic properties of the effective point-field theory action, give a huge class of constructions and devise some techniques for future analysis. Further we study the possibility that the phase-transition from Superstrings to observed particles involves an intermediary phase where the observed particles exhibit compositeness, together with some consequences on the low-energy phenomenology. Finally we include our attempt to modify the SU(5) model, as one of the simplest Grand-unified models, to provide a solution to its difficulties. As we now show, the problems we were trying to address are so generic that some of them remain (in a disguised form) even at the present understanding of the Superstring theories, the most ample constructs of fundamental Physics so far

  8. Stability of mass hierarchy in locally supersymmetric grand unification

    International Nuclear Information System (INIS)

    Nishino, H.; Helayel-Neto, J.A.; Koh, I.G.

    1984-06-01

    Some locally supersymmetric SU(5) grand unified models with a sliding singlet and two pairs of 5sub(tilde) and 5sub(tilde)* Higgs multiplets are considered from the viewpoint of universal baryon asymmetry and the one-loop stability of mass hierarchy. A new mechanism based on ''sliding singlet reflection symmetry'' to avoid the problem of the mass hierarchical stability is proposed. The stability is shown up to two-loop levels for some models. All order stability is also discussed. (author)

  9. Abelian gauge symmetries in F-theory and dual theories

    Science.gov (United States)

    Song, Peng

    In this dissertation, we focus on important physical and mathematical aspects, especially abelian gauge symmetries, of F-theory compactifications and its dual formulations within type IIB and heterotic string theory. F-theory is a non-perturbative formulation of type IIB string theory which enjoys important dualities with other string theories such as M-theory and E8 x E8 heterotic string theory. One of the main strengths of F-theory is its geometrization of many physical problems in the dual string theories. In particular, its study requires a lot of mathematical tools such as advanced techniques in algebraic geometry. Thus, it has also received a lot of interests among mathematicians, and is a vivid area of research within both the physics and the mathematics community. Although F-theory has been a long-standing theory, abelian gauge symmetry in Ftheory has been rarely studied, until recently. Within the mathematics community, in 2009, Grassi and Perduca first discovered the possibility of constructing elliptically fibered varieties with non-trivial toric Mordell-Weil group. In the physics community, in 2012, Morrison and Park first made a major advancement by constructing general F-theory compactifications with U(1) abelian gauge symmetry. They found that in such cases, the elliptically-fibered Calabi-Yau manifold that F-theory needs to be compactified on has its fiber being a generic elliptic curve in the blow-up of the weighted projective space P(1;1;2) at one point. Subsequent developments have been made by Cvetic, Klevers and Piragua extended the works of Morrison and Park and constructed general F-theory compactifications with U(1) x U(1) abelian gauge symmetry. They found that in the U(1) x U(1) abelian gauge symmetry case, the elliptically-fibered Calabi-Yau manifold that F-theory needs to be compactified on has its fiber being a generic elliptic curve in the del Pezzo surface dP2. In chapter 2 of this dissertation, I bring this a step further by

  10. Electroweak unification and tree unitarity

    International Nuclear Information System (INIS)

    Horejsi, J.

    1993-01-01

    The monograph is an unconventional introduction into the theory of unification of weak and electromagnetic interactions, which is conceptually different from the exposition presented in standard textbooks. A detailed explanation is given of the way to the standard model of electroweak interactions which is based on a straightforward application of the requirement of renormalizability of the perturbation series expansion. The procedure to derive the model is interesting as it demonstrates the necessity of introducing vector bosons and Yang-Mills type interactions and at least one elementary scalar boson to obtain a renormalizable theory of weak and electromagnetic interactions. The book is divided into 5 chapters: introduction, problems encountered in a Fermi type theory, the intermediate vector boson, electrodynamics of vector bosons, tree unitarity, and electroweak interactions. Each chapter is completed with exercise problems to be solved by the reader. The text is supplemented with a number of appendices. The monograph is aimed at undergraduate and postgraduate students as well as at physicists interested in the theory of elementary particles. (Z.J.)

  11. Aspects of the flipped unification of strong, weak and electromagnetic interactions

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, J.; Hagelin, J.S.; Kelley, S.; Nanopoulos, D.V.

    1988-12-19

    We explore phenomenological aspects of a recently proposed flipped SU(5) x U(1) supersymmetric GUT which incorporates an economical and natural mechanism for splitting Higgs doublets and triplets, and can be derived from string theory. Using experimental values of sin/sup 2/theta/sub W/ and the strong QCD coupling, we estimate the grand unification scale M/sub G/, where the strong and weak coupling strengths are equal, and the superunification scale M/sub SU/, where all couplings are equal. We find typical values of M/sub G/ approx. = 10/sup 15/ to 10/sup 17/ GeV, with M/sub SU/ somewhat higher and close to the value suggested by string models. We discuss different mechanisms for baryon decay, finding that the dominant one is gauge-boson exchange giving rise to p -> e/sup +/ /sup 0/, anti /sup +/ and n -> e/sup +/ /sup -/, anti /sup 0/ with partial lifetimes approx. = 10/sup 35+-2/ y. We show that a large GUT symmetry-breaking scale M/sub G/ is naturally generated by radiative corrections to the effective potential if a small amount approx. = m/sub W/ of soft supersymmetry breaking is generated dynamically at a large scale. We analyze the low-energy effective theory obtained using the renormalization group equations, demonstrating that electroweak symmetry breaking is obtained if m/sub t/ approx. = 60 to 90 GeV. We analyze the spectrum of sparticles, with particular attention to neutralinos.

  12. On the question of establishing the equivalence of general relativity and relativistic theory of gravitation

    International Nuclear Information System (INIS)

    Kulyabov, D.S.

    2010-01-01

    Full text: (author)In the construction of physical theories are several paradigms (according to Vladimirov Yu. S.). Depending on the number of entities are used paradigms include trialist (3 entities), dualist (2 entities) and monistic (1 entity). In trialist paradigm uses the following entities: geometry (G), particle (P) and field (F). Go to the dualist paradigms performed in the following ways: two entities take over the functions of the third, two entities merged into a single synthesis. Is also possible to limit the dualistic theory, which summarized the essence in addition assume the functions of a third. In turn, by way of grouping the entities dualistic theory can be divided into geometric (unification of geometry and field), relational (unification of geometry and particles) and field (unification of fields and particles). For the connection of the two theories should be to go to the common denominator: to trialist or monistic theories. Since the monistic theory at the moment completely unknown, may be used only trialist theory. General relativity is a typical representative of the geometric dualistic paradigm. However geometrized only gravity. Other fields non-geometrized. In turn, the relativistic theory of gravitation is a typical trialist theory. To establish a correspondence between theories should to geometrize material field in the general theory of relativity. It is proposed to implement this on the basis of a multi-dimensional Kaluza-Klein theory

  13. Scalar mass relations and flavor violations in supersymmetric theories

    International Nuclear Information System (INIS)

    Cheng, Hsin-Chia; California Univ., Berkeley, CA

    1996-01-01

    Supersymmetry provides the most promising solution to the gauge hierarchy problem. For supersymmetry to stablize the hierarchy, it must be broken at the weak scale. The combination of weak scale supersymmetry and grand unification leads to a successful prediction of the weak mixing angle to within 1% accuracy. If supersymmetry is a symmetry of nature, the mass spectrum and the flavor mixing pattern of the scalar superpartners of all the quarks and leptons will provide important information about a more fundamental theory at higher energies. We studied the scalar mass relations which follow from the assumption that at high energies there is a grand unified theory which leads to a significant prediction of the weak mixing angle; these will serve as important tests of grand unified theories. Two intragenerational mass relations for each of the light generations are derived. A third relation is also found which relates the Higgs masses and the masses of all three generation scalars. In a realistic supersymmetric grand unified theory, nontrivial flavor mixings are expected to exist at all gaugino vertices. This could lead to important contributions to the neutron electric dipole moment, the decay mode p → K 0 μ + , weak scale radiative corrections to the up-type quark masses, and lepton flavor violating signals such as μ → eγ. These also provide important probes of physics at high energy scales. Supersymmetric theories involving a spontaneously broken flavor symmetry can provide a solution to the supersymmetric flavor-changing problem and an understanding of the fermion masses and mixings. We studied the possibilities and the general conditions under which some fermion masses and mixings can be obtained radiatively. We also constructed theories of flavor in which the first generation fermion masses arise from radiative corrections while flavor-changing constraints are satisfied. 69 refs., 19 figs., 9 tabs

  14. Quantum gravity unification via transfinite arithmetic and geometrical averaging

    International Nuclear Information System (INIS)

    El Naschie, M.S.

    2008-01-01

    In E-Infinity theory, we have not only infinitely many dimensions but also infinitely many fundamental forces. However, due to the hierarchical structure of ε (∞) spacetime we have a finite expectation number for its dimensionality and likewise a finite expectation number for the corresponding interactions. Starting from the preceding fundamental principles and using the experimental findings as well as the theoretical value of the coupling constants of the electroweak and the strong forces we present an extremely simple averaging procedure for determining the quantum gravity unification coupling constant with and without super symmetry. The work draws heavily on previous results, in particular a paper, by the Slovian Prof. Marek-Crnjac [Marek-Crnjac L. On the unification of all fundamental forces in a fundamentally fuzzy Cantorian ε (∞) manifold and high energy physics. Chaos, Solitons and Fractals 2004;4:657-68

  15. F-theory and all things rational: surveying U(1) symmetries with rational sections

    International Nuclear Information System (INIS)

    Lawrie, Craig; Schäfer-Nameki, Sakura; Wong, Jin-Mann

    2015-01-01

    We study elliptic fibrations for F-theory compactifications realizing 4d and 6d supersymmetric gauge theories with abelian gauge factors. In the fibration these U(1) symmetries are realized in terms of additional rational section. We obtain a universal characterization of all the possible U(1) charges of matter fields by determining the corresponding codimension two fibers with rational sections. In view of modelling supersymmetric Grand Unified Theories, one of the main examples that we analyze are U(1) symmetries for SU(5) gauge theories with 5̄ and 10 matter. We use a combination of constraints on the normal bundle of rational curves in Calabi-Yau three- and four-folds, as well as the splitting of rational curves in the fibers in codimension two, to determine the possible configurations of smooth rational sections. This analysis straightforwardly generalizes to multiple U(1)s. We study the flops of such fibers, as well as some of the Yukawa couplings in codimension three. Furthermore, we carry out a universal study of the U(1)-charged GUT singlets, including their KK-charges, and determine all realizations of singlet fibers. By giving vacuum expectation values to these singlets, we propose a systematic way to analyze the Higgsing of U(1)s to discrete gauge symmetries in F-theory.

  16. L’origine de l’emploi de la forme analogique grande : concordance de genre ou identification du référent ?

    Directory of Open Access Journals (Sweden)

    Xia Haoyu Irene

    2016-01-01

    Full Text Available L’objectif de la présente étude est de déterminer les raisons pour lesquelles un auteur du XVIe siècle aurait choisi la nouvelle forme analogique grande plutôt que la forme épicène grand. L’étude est basée sur un corpus de 1341 occurrences de cet adjectif au féminin dans 17 textes de cinq auteurs. L’hypothèse de l’identification du référent propose qu’un auteur aurait choisi cette forme pour indiquer clairement qu’elle modifie un substantif féminin et assurer ainsi le lien entre l’adjectif et le substantif. L’hypothèse de la concordance de genre propose que l’auteur aurait choisi grande pour faire accorder l’adjectif aux autres éléments féminins dans le syntagme nominal. Les résultats ont partiellement validé les deux hypothèses. La forme grande est favorisée quand elle ne précède pas immédiatement le substantif féminin qu’elle qualifie et quand un substantif masculin intervient entre le substantif féminin et grande. La forme analogique est aussi favorisée fortement par un déterminant féminin en -e et plus légèrement par la, mais pas par d’autres déterminants féminins. Nous avons trouvé en plus un résultat inattendu. La variante analogique est favorisée fortement quand elle modifie un substantif avec un plus grand nombre de syllabes et défavorisée par un substantif plus court.

  17. Summary talk

    International Nuclear Information System (INIS)

    Harari, H.

    1978-10-01

    A general overview is given in this high energy physics conference summary. Quantum chromodynamics as a theory of strong interactions and studied by experimental tests, SU(2) x U(1) theory of weak and electromagnetic interactions and its experimental tests, weak interactions above 100 GeV, simple unification of weak and electromagnetic interactions, and the grand and the ultimate unifications with extended supergravity are discussed. 28 references

  18. Astrophysical Probes of Varying Constants and Unification

    International Nuclear Information System (INIS)

    Martins, C J A P

    2016-01-01

    The observational evidence for the acceleration of the universe demonstrates that canonical theories of gravitation and particle physics are incomplete, if not incorrect. A new generation of astronomical facilities will soon carry out precision consistency tests of the standard cosmological model and search for evidence of new physics beyond it. I describe recent work of CAUP's Dark Side team on some of these tests, focusing on the stability of nature's fundamental couplings and tests of unification scenarios. (paper)

  19. New Developments in Supersymmetry (1/5)

    CERN Multimedia

    CERN. Geneva

    2001-01-01

    Introduction to supersymmetric grand unified theories. An introduction to the MSSM and different mechanisms for supersymmetry breaking. Then the details of SU(5) and SO(10) unification, the new gauge sector beyond the standard model, representations of quarks and leptons. Gauge and Yukawa coupling unification and some predictions.

  20. New Developments in Supersymmetry (2/5)

    CERN Multimedia

    CERN. Geneva

    2001-01-01

    Introduction to supersymmetric grand unified theories. An introduction to the MSSM and different mechanisms for supersymmetry breaking. Then the details of SU(5) and SO(10) unification, the new gauge sector beyond the standard model, representations of quarks and leptons. Gauge and Yukawa coupling unification and some predictions.

  1. New Developments in Supersymmetry (5/5)

    CERN Multimedia

    CERN. Geneva

    2001-01-01

    Introduction to supersymmetric grand unified theories. An introduction to the MSSM and different mechanisms for supersymmetry breaking. Then the details of SU(5) and SO(10) unification, the new gauge sector beyond the standard model, representations of quarks and leptons. Gauge and Yukawa coupling unification and some predictions.

  2. New Developments in Supersymmetry (3/5)

    CERN Multimedia

    CERN. Geneva

    2001-01-01

    Introduction to supersymmetric grand unified theories. An introduction to the MSSM and different mechanisms for supersymmetry breaking. Then the details of SU(5) and SO(10) unification, the new gauge sector beyond the standard model, representations of quarks and leptons. Gauge and Yukawa coupling unification and some predictions.

  3. The quest of a unified theory of interactions

    International Nuclear Information System (INIS)

    Weingerg, St.; Hawking, St.; Mlodinow, L.; Lisi, G.; Weatherall, J.

    2011-01-01

    The unification of the 4 basic interactions is far from being achieved despite all the efforts made during decades. One theory states that unification is not possible unless to have the point of view of an observer outside the universe...This document is composed of 3 articles. In the first article, stakes, difficulties and the existing research axis of unification are presented. The second article is dedicated to the string theory that is the most promising according to scientists. In fact there are 5 string theories, each one explaining a limited range of phenomena. Nevertheless, string theories share common concepts called dualities, which made physicists think of a unique theory: the M theory that might lie behind the string theories. The third article presents a recent attempt of unification based on the E8 Lie group. Even if this E8 theory appears to be wrong, it will have shed light on deep geometrical relationships between particles that the real theory will have to explain. (A.C.)

  4. Towards a unification of the hierarchical reference theory and the self-consistent Ornstein-Zernike approximation.

    Science.gov (United States)

    Reiner, A; Høye, J S

    2005-12-01

    The hierarchical reference theory and the self-consistent Ornstein-Zernike approximation are two liquid state theories that both furnish a largely satisfactory description of the critical region as well as phase coexistence and the equation of state in general. Furthermore, there are a number of similarities that suggest the possibility of a unification of both theories. As a first step towards this goal, we consider the problem of combining the lowest order gamma expansion result for the incorporation of a Fourier component of the interaction with the requirement of consistency between internal and free energies, leaving aside the compressibility relation. For simplicity, we restrict ourselves to a simplified lattice gas that is expected to display the same qualitative behavior as more elaborate models. It turns out that the analytically tractable mean spherical approximation is a solution to this problem, as are several of its generalizations. Analysis of the characteristic equations shows the potential for a practical scheme and yields necessary conditions that any closure to the Ornstein-Zernike relation must fulfill for the consistency problem to be well posed and to have a unique differentiable solution. These criteria are expected to remain valid for more general discrete and continuous systems, even if consistency with the compressibility route is also enforced where possible explicit solutions will require numerical evaluations.

  5. On grand unified SU(8)sub(L) x SU(8)sub(R) model

    International Nuclear Information System (INIS)

    Pirogov, Yu.F.

    1980-01-01

    In the model of early chiral grand unification SU(8)sub(L)xSU(8)sub(R) with intermediate symmetry hierarchies the radiation corrections for sinsup(2)thetasub(W)(μ) and α(μ) are calculated and unification mass M 8 is found in the one loop approximation with Higgs fields contribution being neglected. It is shown that there exists a natural hierarchy, leading to the decrease of sinsup(2)thetasub(W)(Msub(W)) down to the value sinsup(2)thetasub(W)=1/5-1/4 and simultaneous decrease of M 8 down to M 8 =(10 6 -10 7 ) GeV as compared with the values when there is no hierarchy [ru

  6. Genesis of Electroweak Unification and the Higgs

    CERN Multimedia

    CERN. Geneva

    2014-01-01

    I will give a historical account of the developments leading up to the unification of weak and electromagnetic interactions, as I saw them from my standpoint in Imperial College London. I will describe the state of physics in the 1950s, the aim of finding a unified theory of various interactions, the obstacles encountered in trying to unify the weak and electromagnetic interactions, and their eventual resolution, with a brief discussion of the later history culminating in the discovery of the Higgs boson in 2012.

  7. Unification of electromagnetic, strong and weak interaction

    International Nuclear Information System (INIS)

    Duong Van Phi; Duong Anh Duc

    1993-09-01

    The Unification of Electromagnetic, Strong and Weak Interactions is realized in the framework of the Quantum Field Theory, established in an 8-dimensional Unified Space. Two fundamental, spinor and vector field equations are considered. The first of the matter particles and the second is of the gauge particles. Interaction Lagrangians are formed from the external and internal currents and the external and internal vector field operators. Generators of the local gauge transformations are the combinations of the matrices of the first field equation. (author). 15 refs

  8. Supersymmetric grand unified theories and cosmology

    International Nuclear Information System (INIS)

    Lazarides, G.; Shafi, Q.

    1983-01-01

    By examining the behavior of supersymmetric grand unified theories (GUT's) in the very early universe we find two classes of realistic models. In one of them supersymmetry is broken at or near superheavy GUT scale. The cosmological implications of such models are expected to be similar to those of nonsupersymmetric GUT's. In the second class of models, the superheavy GUT scale is related to the supersymmetry-breaking scale in the manner of Witten. Two types of cosmological scenarios appear possible in this case, either with or without an intermediate (new) inflationary phase. They can be experimentally distinguished, since the former predicts an absence and the latter an observable number density of superheavy monopoles. A mechanism for generating baryon asymmetry in such models is pointed out

  9. Future dynamics in f(R) theories

    International Nuclear Information System (INIS)

    Mueller, D.; Andrade, V.C. de; Maia, C.; Reboucas, M.J.; Teixeira, A.F.F.

    2015-01-01

    The f(R) gravity theories provide an alternative way to explain the current cosmic acceleration without invoking a dark energy matter component used in the cosmological modeling in the framework of general relativity. However, the freedom in the choice of the functional forms of f(R) gives rise to the problem of the degeneracy among these gravity theories on theoretical and (or) observational grounds. In this paper we examine the question as to whether the future dynamics can be used to break the degeneracy between f(R) gravity theories by investigating the dynamics of spatially homogeneous and isotropic dust flat models in two f(R) gravity theories, namely the well known f(R) = R+αR n gravity and another byAviles et al., whose motivation comes from the cosmographic approach to f(R) gravity. We perform a detailed numerical study of the dynamics of these theories taking into account the recent constraints on the cosmological parameters made by the Planck Collaboration. We demonstrate that besides being useful for discriminating between these two f(R) gravity theories, the future dynamics technique can also be used to determine the finite-time behavior as well as the fate of the Universe in the framework of these f(R) gravity theories. There also emerges from our analysis the result that one still can have a dust flat FLRWsolution with a big rip, if gravity is governed by f(R) = R+αR n . We also show that FLRW dust solutions with f'' < 0 do not necessarily lead to singularities. (orig.)

  10. f(Lovelock) theories of gravity

    Science.gov (United States)

    Bueno, Pablo; Cano, Pablo A.; Óscar Lasso, A.; Ramírez, Pedro F.

    2016-04-01

    f(Lovelock) gravities are simple generalizations of the usual f( R) and Lovelock theories in which the gravitational action depends on some arbitrary function of the corresponding dimensionally-extended Euler densities. In this paper we study several aspects of these theories in general dimensions. We start by identifying the generalized boundary term which makes the gravitational variational problem well-posed. Then, we show that these theories are equivalent to certain scalar-tensor theories and how this relation is characterized by the Hessian of f. We also study the linearized equations of the theory on general maximally symmetric backgrounds. Remarkably, we find that these theories do not propagate the usual ghost-like massive gravitons characteristic of higher-derivative gravities on such backgrounds. In some non-trivial cases, the additional scalar associated to the trace of the metric perturbation is also absent, being the usual graviton the only dynamical field. In those cases, the linearized equations are exactly the same as in Einstein gravity up to an overall factor, making them appealing as holographic toy models. We also find constraints on the couplings of a broad family of five-dimensional f(Lovelock) theories using holographic entanglement entropy. Finally, we construct new analytic asymptotically flat and AdS/dS black hole solutions for some classes of f(Lovelock) gravities in various dimensions.

  11. f(Lovelock) theories of gravity

    International Nuclear Information System (INIS)

    Bueno, Pablo; Cano, Pablo A.; Óscar, Lasso A.; Ramírez, Pedro F.

    2016-01-01

    f(Lovelock) gravities are simple generalizations of the usual f(R) and Lovelock theories in which the gravitational action depends on some arbitrary function of the corresponding dimensionally-extended Euler densities. In this paper we study several aspects of these theories in general dimensions. We start by identifying the generalized boundary term which makes the gravitational variational problem well-posed. Then, we show that these theories are equivalent to certain scalar-tensor theories and how this relation is characterized by the Hessian of f. We also study the linearized equations of the theory on general maximally symmetric backgrounds. Remarkably, we find that these theories do not propagate the usual ghost-like massive gravitons characteristic of higher-derivative gravities on such backgrounds. In some non-trivial cases, the additional scalar associated to the trace of the metric perturbation is also absent, being the usual graviton the only dynamical field. In those cases, the linearized equations are exactly the same as in Einstein gravity up to an overall factor, making them appealing as holographic toy models. We also find constraints on the couplings of a broad family of five-dimensional f(Lovelock) theories using holographic entanglement entropy. Finally, we construct new analytic asymptotically flat and AdS/dS black hole solutions for some classes of f(Lovelock) gravities in various dimensions.

  12. Neutrino masses and the unification of the SO(10) families

    International Nuclear Information System (INIS)

    Maalampi, J.; Enqvist, K.

    1980-01-01

    We show that the unification of the SO(10) families in SO(10+m) group can offer a solution to the neutrino mass problem. For simplicity we have restricted our analysis to SO(11), which contains - aside from generation mixing -the main novel feature of the theories of this kind: fermions that couple by V+A charged weak currents. (author)

  13. Effective actions for F-theory compactifications and tensor theories

    International Nuclear Information System (INIS)

    Bonetti, Federico

    2014-01-01

    In this thesis we study the low-energy effective dynamics emerging from a class of F-theory compactifications in four and six dimensions. We also investigate six-dimensional supersymmetric quantum field theories with self-dual tensors, motivated by the problem of describing the long-wavelength regime of a stack of M5-branes in M-theory. These setups share interesting common features. They both constitute examples of intrinsically non-perturbative physics. On the one hand, in the context of F-theory the non-perturbative character is encoded in the geometric formulation of this class of string vacua, which allows the complexified string coupling to vary in space. On the other hand, the dynamics of a stack of multiple M5-branes flows in the infrared to a novel kind of superconformal field theories in six dimensions - commonly referred to as (2,0) theories - that are expected to possess no perturbative weakly coupled regime and have resisted a complete understanding so far. In particular, no Lagrangian description is known for these models. The strategy we employ to address these two problems is also analogous. A recurring Leitmotif of our work is a transdimensional treatment of the system under examination: in order to extract information about dynamics in d dimensions we consider a (d-1)-dimensional setup. As far as F-theory compactifications are concerned, this is a consequence of the duality between M-theory and F-theory, which constitutes our main tool in the derivation of the effective action of F-theory compactifications. We apply it to six-dimensional F-theory vacua, obtained by taking the internal space to be an elliptically fibered Calabi-Yau threefold, but we also employ it to explore a novel kind of F-theory constructions in four dimensions based on manifolds with Spin(7) holonomy. With reference to six-dimensional (2,0) theories, the transdimensional character of our approach relies in the idea of studying these theories in five dimensions. Indeed, we

  14. Heterotic brane world

    International Nuclear Information System (INIS)

    Nilles, H.-P.

    2004-01-01

    Heterotic E 8 x E 8 string theory is a promising source of grand unified model building. It can accommodate the successful aspects of grand unification while avoiding problems like doublet-triplet splitting in the Higgs sector and fast proton decay. We exploit the geometrical properties of the theory as a guideline for realistic model building. (author)

  15. Natural embedding of Peccei-Quinn symmetry in flavor grand unification

    International Nuclear Information System (INIS)

    Kim, J.E.

    1981-08-01

    Peccei and Quinn's global U(1)sub(A) symmetry can be embedded in grand unified schemes without an artificial requirement of imposing U(1)sub(A) symmetry, which results from the representation content of fermions and Higgs fields. Then, in some cases there results an ordinary axion with a mass approximately 100 keV. The axion mass is proportional to v -1 sub(A), where v -1 sub(A) is the scale of the actual U(1)sub(A) symmetry breakdown. (author)

  16. Chiral symmetry and eta, eta' → 3π decays. Grand unified theories

    International Nuclear Information System (INIS)

    Roiesnel, C.

    1982-11-01

    Two different topics related to symmetry breaking are discussed. First the eta, eta' → 3π decays are presented. The amplitudes eta, eta' → 3π are calculated with the square root threshold singularity induced by the strong pion-pion final state interaction properly taken into account. It is shown that the eta' → 3π decay rate depends sensitively upon an improved treatment of the pseudoscalar nonet mass matrix. Then symmetry-breaking effects in grand unified theories are discussed. The threshold effects in a spontaneously broken gauge theory are studied. In particular a computation of the symmetry-breaking effects in the SU(5) grand unified theory including those of the breaking of SU(2)xU(1) is presented. As an application a precise value of the superheavy gauge boson mass Mx is given. It is possible in SU(5) to define a natural effective weak angle theta w(μ) for any scale μ, below as well as above Mw, and the predicted curve for sin 2 theta w(μ) is given [fr

  17. Restrictions on two Higgs doublet models and CP violation at the unification scale

    International Nuclear Information System (INIS)

    Athanasiu, G.G.

    1987-01-01

    In Part I we examine bounds from CP violation in the neutral K system on charged Higgs masses and couplings in models with two Higgs doublets. While CP violation is still due only to a non-zero phase in the Kobayashi-Maskawa matrix, there are additional short-distance contributions involving charged Higgs exchange rather than W boson exchange. By having CP violation in the mass matrix, but not in the kaon to two pions decay amplitude, largely due to Higgs exchange, it is possible to obtain a small value of ε'/ε. In Part II we obtain bounds on charged-Higgs-boson masses and couplings in two Higgs doublet models from their effects on neutral-B-meson mixing. The bounds are comparable to those obtained with additional assumptions from the neutral-K-system. Neutral-Higgs-boson effects on the spectrum and wave functions of tt bound states are examined in the same model. In the future they could lead to restrictions on, or discovery of, the corresponding neutral Higgs bosons if they have relatively low masses and enhanced couplings. Finally, in Part III, the three generation phase invariant measure of CP violation is shown to satisfy a simple and solvable renormalization group equation. Its value falls by four to eight orders of magnitude between the weak and grand unification scales in the standard model, as well as in its two Higgs and supersymmetric extensions. Such a small value of CP violation at the grand unification scale can pose a problem for baryogenesis; this avoided if there are heavy quarks with masses close to their fixed points

  18. Quantum field theory in curved spacetime and the dark matter problem

    International Nuclear Information System (INIS)

    Grib, A. A.; Pavlov, Yu. V.

    2007-01-01

    Quantum field theory in nonstationary curved Friedmann spacetime leads to the phenomenon of creation of massive particles. The hypothesis that in the end of inflation gravitation creates from vacuum superheavy particles decaying on quarks and leptons leading to the observed baryon charge is investigated. Taking the complex scalar field for these particles in analogy with K 0 -meson theory one obtains two components - the long living and short living ones, so that the long living component after breaking the Grand Unification symmetry has a long life time and is observed today as dark matter. The hypothesis that ultra high energy cosmic rays occur as manifestation of superheavy dark matter is considered and some experimental possibilities of the proposed scheme are analyzed

  19. How European unification has shaped the debate on measuring international financial integration

    OpenAIRE

    Pieterse-Bloem, Mary; Eijffinger, Sylvester

    2013-01-01

    textabstractIn this paper we analyse a chronicle of economic theory on international financial integration post-WWII to the present date. Our focus is on theories that have somehow quantify the state and speed of international financial integration. We are able to contrast and compare three distinct strands that have brought forward conditions for its measurement. It is shown that European unification provides much of the empirical testing ground for these measures of international financial ...

  20. Low-energy neutral current phenomenology and grand unified theories

    International Nuclear Information System (INIS)

    Del Aguila, F.; Mendez, A.

    1981-01-01

    We derive necessary and sufficient conditions to be satisfied by any expanded electroweak gauge model in order to reproduce the standard model low-energy neutral current predictions. These conditions imply several constraints on the neutral gauge boson masses and the quantum number assignments for the ordinary fermions. Using these conditions, we prove that the popular grand unified theories based on the gauge groups SO(10) and E6 can only accommodate trivial extensions of the standard model. As a consequence, if any of these grand unified models works at some energy scale, present low-energy neutral current phenomenology implies that the Z-boson must be produced with the expected mass and couplings to the ordinary fermions. Any additional neutral gauge boson (with the possible exception of very heavy ones) could only be produced in hadronic collisions and it would not decay in e + e - . (orig.)

  1. Dependence theory via game theory

    NARCIS (Netherlands)

    Grossi, D.; Turrini, P.

    2011-01-01

    In the multi-agent systems community, dependence theory and game theory are often presented as two alternative perspectives on the analysis of social interaction. Up till now no research has been done relating these two approaches. The unification presented provides dependence theory with the sort

  2. New dimensions new hopes

    International Nuclear Information System (INIS)

    Sarkar, Utpal

    2001-05-01

    We live in a four dimensional world. But the idea of unification of fundamental interactions lead us to higher dimensional theories. Recently a new theory with extra dimensions has emerged where only gravity propagates in the extra dimension and all other interactions are confined to only four dimensions. This theory gives us many new hopes. In earlier theories unification of strong, weak and the electromagnetic forces was possible at around 10 16 GeV in a grand unified theory (GUT) and it could get unified with gravity at around the Planck scale of 10 19 GeV. With this new idea it is possible to bring down all unification scales within the reach of the new generation accelerators, i.e., around 10 4 GeV. (author)

  3. Physics and cosmology - geometry for grand unification

    International Nuclear Information System (INIS)

    Heller, M.

    1985-01-01

    Fibre bundle technique to geometrize gauge field theories and possibly to unify physics is presented on the introductory level. Some remarks are made concerning the mutual relationship between physics and cosmology. 21 refs., 10 figs. (author)

  4. Dynamical supersymmetry breaking

    International Nuclear Information System (INIS)

    Affleck, I.

    1985-03-01

    Supersymmetry, and in particular, dynamical supersymmetry breaking, offers the hope of a natural solution of the gauge hierarchy problem in grand unification. I briefly review recent work on dynamical supersymmetry breaking in four-dimensional Higgs theories and its application to grand unified model building

  5. On building superpotentials in F-GUTs

    International Nuclear Information System (INIS)

    Saidi, E. H.

    2016-01-01

    Using characters of finite group representations, we construct the fusion algebras of operators of the spectrum of F-theory grand unified theories (GUTs). These fusion relations are used in building monodromy-invariant superpotentials of the low-energy effective 4D N=1 supersymmetric GUT models

  6. Minimal supersymmetric grand unified theory: Symmetry breaking and the particle spectrum

    International Nuclear Information System (INIS)

    Bajc, Borut; Melfo, Alejandra; Senjanovic, Goran; Vissani, Francesco

    2004-01-01

    We discuss in detail the symmetry breaking and related issues in the minimal renormalizable supersymmetric grand unified theory. We find all the possible patterns of symmetry breaking, compute the associated particle spectrum and study its impact on the physical scales of the theory. In particular, the complete mass matrices of the SU(2) doublets and the color triplets are computed in connection with the doublet-triplet splitting and the d=5 proton decay. We explicitly construct the two light Higgs doublets as a function of the Higgs superpotential parameters. This provides a framework for the analysis of phenomenological implications of the theory, to be carried out in a second paper

  7. Two exercises in supersymmetry: a low-energy supergravity model and free string field theory

    International Nuclear Information System (INIS)

    Preitschopf, C.R.

    1986-09-01

    The new features of a supersymmetric standard model in the presence of heavy families are studied. The minimal set of Higgs fields, the desert between the electroweak and the grand unification scale and perturbative values of the dimensionless parameters throughout this region are assumed. Using the numerical as well as the approximate analytic solution of the renormalization group equations, the evolution of all the parameters of the theory are studied in the case of large Yukawa couplings for the fourth family. The desired spontaneous symmetry breaking of the electroweak symmetry takes place only for a rather unnatural choice of the initial values of certain mass parameters at the grand unification scale. If it is gravitino mass smaller than 200 GeV the vacuum expectation values of the Higgs fields emerge necessarily in an interplay of the tree level Higgs potential and its quantum corrections and are approximately equal. The qurak masses of the fourth family are roughly 135 GeV, while the mass of the fourth charged lepton has an upper bound of 90 GeV. Further characteristic features of this scenario are one light neutral Higgs field of mass 50 GeV and gluino masses below 75 GeV. If the gravitino mass is higher than 200 GeV one obtains a scaled up version of the well-known three family, heavy top scenario with quark masses between 40 and 205 GeV and all superparticle masses heavier than 150 GeV except the photino, gluino, one chargino and one neutralino. The gauge-invariant theory of the free bosonic open string is generalized to treat closed strings and superstrings. All of these theories can be written as theories of string differential forms defined on suitable spaces. All of the bosonic theories have exactly the same structure; the Ramond theory takes an analogous first-order form. We show explicitly, how to gauge-fix each action to the light-cone gauge and to the Feynman-Siegel gauge

  8. Beyond the Standard Model (2/5)

    CERN Multimedia

    CERN. Geneva

    2000-01-01

    After a critical discussion of the questions left unanswered by the Standard Model, I will review the main attemps to construct new theories. In particular, I will discuss grand unification, supersymmetry, technicolour, and theories with extra dimensions.

  9. Beyond the Standard Model (5/5)

    CERN Multimedia

    CERN. Geneva

    2000-01-01

    After a critical discussion of the questions left unanswered by the Standard Model, I will review the main attemps to construct new theories. In particular, I will discuss grand unification, supersymmetry, technicolour, and theories with extra dimensions.

  10. Beyond the Standard Model (3/5)

    CERN Multimedia

    CERN. Geneva

    2000-01-01

    After a critical discussion of the questions left unanswered by the Standard Model, I will review the main attemps to construct new theories. In particular, I will discuss grand unification, supersymmetry, technicolour, and theories with extra dimensions.

  11. Beyond the Standard Model (4/5)

    CERN Multimedia

    CERN. Geneva

    2000-01-01

    After a critical discussion of the questions left unanswered by the Standard Model, I will review the main attemps to construct new theories. In particular, I will discuss grand unification, supersymmetry, technicolour, and theories with extra dimensions.

  12. Beyond the Standard Model (1/5)

    CERN Multimedia

    CERN. Geneva

    2000-01-01

    After a critical discussion of the questions left unanswered by the Standard Model, I will review the main attemps to construct new theories. In particular, I will discuss grand unification, supersymmetry, technicolour, and theories with extra dimensions.

  13. Quantum kinetic field theory in curved spacetime: Covariant Wigner function and Liouville-Vlasov equations

    International Nuclear Information System (INIS)

    Calzetta, E.; Habib, S.; Hu, B.L.

    1988-01-01

    We consider quantum fields in an external potential and show how, by using the Fourier transform on propagators, one can obtain the mass-shell constraint conditions and the Liouville-Vlasov equation for the Wigner distribution function. We then consider the Hadamard function G 1 (x 1 ,x 2 ) of a real, free, scalar field in curved space. We postulate a form for the Fourier transform F/sup (//sup Q//sup )/(X,k) of the propagator with respect to the difference variable x = x 1 -x 2 on a Riemann normal coordinate centered at Q. We show that F/sup (//sup Q//sup )/ is the result of applying a certain Q-dependent operator on a covariant Wigner function F. We derive from the wave equations for G 1 a covariant equation for the distribution function and show its consistency. We seek solutions to the set of Liouville-Vlasov equations for the vacuum and nonvacuum cases up to the third adiabatic order. Finally we apply this method to calculate the Hadamard function in the Einstein universe. We show that the covariant Wigner function can incorporate certain relevant global properties of the background spacetime. Covariant Wigner functions and Liouville-Vlasov equations are also derived for free fermions in curved spacetime. The method presented here can serve as a basis for constructing quantum kinetic theories in curved spacetime or for near-uniform systems under quasiequilibrium conditions. It can also be useful to the development of a transport theory of quantum fields for the investigation of grand unification and post-Planckian quantum processes in the early Universe

  14. Higgs mass scales and matter-antimatter oscillations in grand unified theories

    International Nuclear Information System (INIS)

    Senjanovic, G.

    1982-01-01

    A general discussion of mass scales in grand unified theories is presented, with special emphasis on Higgs scalars which mediate neutron-antineutron (n-anti n) and hydrogen-antihydrogen (H-anti H) oscillations. It is shown that the analogue of survival hypothesis for fermions naturally makes such particles superheavy, thus leading to unobservable lifetimes. If this hypothesis is relaxed, an interesting possibility of potentially observable n-anti n and H-anti H transitions, mutually related arises in the context of SU(5) theory with spontaneously broken B-L symmetry

  15. SU(8) family unification with boson-fermion balance

    CERN Multimedia

    CERN. Geneva

    2014-01-01

    Grand unification has been intensively investigated for over forty years, and many different approaches have been tried. In this talk I propose a model that involves three ingredients that do not appear in the usual constructions: (1) boson--fermion balance without full supersymmetry, (2) canceling the spin 1/2 fermion gauge anomalies against the anomaly from a gauged spin 3/2 gravitino, and (3) using a scalar field representation with non-zero U(1) generator to break the SU(8) gauge symmetry through a ground state which, before dynamical symmetry breaking, has a periodic U(1) generator structure. The model has a number of promising features: (1) natural incorporation of three families, (2) incorporation of the experimentally viable flipped SU(5) model, (3) a symmetry breaking pathway to the standard model using the scalar field required by boson-fermion balance, together with a stage of most attractive channel dynamical symmetry breaking, without postulating additional Higgs fields, (4) vanishing of bare Yuk...

  16. Unification of string dualities

    International Nuclear Information System (INIS)

    Sen, A.

    1997-01-01

    We argue that all conjectured dualities involving various string, M- and F-theory compactifications can be 'derived' from the conjectured duality between type I and SO(32) heterotic string theory, T-dualities and the definition of M-and F-theories. (orig.)

  17. Gauge coupling unification in superstring derived standard-like models

    International Nuclear Information System (INIS)

    Faraggi, A.E.

    1992-11-01

    I discuss gauge coupling unification in a class of superstring standard-like models, which are derived in the free fermionic formulation. Recent calculations indicate that the superstring unification scale is at O(10 18 GeV) while the minimal supersymmetric standard model is consistent with LEP data if the unification scale is at O(10 16 )GeV. A generic feature of the superstring standard-like models is the appearance of extra color triplets (D,D), and electroweak doublets (l,l), in vector-like representations, beyond the supersymmetric standard model. I show that the gauge coupling unification at O(10 18 GeV) in the superstring standard-like models can be consistent with LEP data. I present an explicit standard-like model that can realize superstring gauge coupling unification. (author)

  18. Heterotic String/F-theory Duality from Mirror Symmetry

    CERN Document Server

    Berglund, Per

    1998-01-01

    We use local mirror symmetry in type IIA string compactifications on Calabi-Yau n+1 folds $X_{n+1}$ to construct vector bundles on (possibly singular) elliptically fibered Calabi-Yau n-folds Z_n. The interpretation of these data as valid classical solutions of the heterotic string compactified on Z_n proves F-theory/heterotic duality at the classical level. Toric geometry is used to establish a systematic dictionary that assigns to each given toric n+1-fold $X_{n+1}$ a toric n fold Z_n together with a specific family of sheafs on it. This allows for a systematic construction of phenomenologically interesting d=4 N=1 heterotic vacua, e.g. on deformations of the tangent bundle, with grand unified and SU(3)\\times SU(2) gauge groups. As another application we find non-perturbative gauge enhancements of the heterotic string on singular Calabi-Yau manifolds and new non-perturbative dualities relating heterotic compactifications on different manifolds.

  19. Toric Methods in F-Theory Model Building

    Directory of Open Access Journals (Sweden)

    Johanna Knapp

    2011-01-01

    Full Text Available We discuss recent constructions of global F-theory GUT models and explain how to make use of toric geometry to do calculations within this framework. After introducing the basic properties of global F-theory GUTs, we give a self-contained review of toric geometry and introduce all the tools that are necessary to construct and analyze global F-theory models. We will explain how to systematically obtain a large class of compact Calabi-Yau fourfolds which can support F-theory GUTs by using the software package PALP.

  20. The nonsymmetric-nonabelian Kaluza-Klein theory

    International Nuclear Information System (INIS)

    Kalinowski, M.W.

    1983-01-01

    This paper is devoted to an (n+4)-dimensional unification of Moffat's theory of gravitation and Yang-Mills field theory with nonabelian gauge group G. We found 'interference effects' between gravitational and Yang-Mills (gauge) fields which appear to be due to the skewsymmetric part of the metric of Moffat's theory and the skewsymmetric part of the metric on the group G. Our unification, called the nonsymmetric-nonabelian Kaluza-Klein theory, becomes classical Kaluza-Klein theory if the skewsymmetric parts of both metrics are zero. (author)

  1. Violation of the Appelquist-Carazzone decoupling in a nonsupersymmetric grand unified theory

    International Nuclear Information System (INIS)

    Chankowski, Piotr H.; Wagner, Jakub

    2008-01-01

    We point out that in nonsupersymmetric grand unified theories, in which the SU(5) gauge symmetry is broken down to the standard model gauge group by a 24 Higgs multiplet the Appelquist-Carazzone decoupling is violated. This is because the SU(2) L Higgs triplet contained in the 24 acquires a dimension-full coupling to the SU(2) L Higgs doublets which is proportional to the grand unified symmetry breaking vacuum expectation value. As a result, at one-loop heavy gauge and Higgs fields contribution to tadpoles generates a vacuum expectation value of the triplet which is not suppressed for V→∞ and violates the custodial symmetry

  2. Induced gravity II: grand unification

    Energy Technology Data Exchange (ETDEWEB)

    Einhorn, Martin B. [Kavli Institute for Theoretical Physics, Kohn Hall,University of California,Santa Barbara, CA 93106-4030 (United States); Jones, D.R. Timothy [Kavli Institute for Theoretical Physics, Kohn Hall,University of California,Santa Barbara, CA 93106-4030 (United States); Dept. of Mathematical Sciences, University of Liverpool,Peach Street, Liverpool L69 3BX (United Kingdom)

    2016-05-31

    As an illustration of a renormalizable, asymptotically-free model of induced gravity, we consider an SO(10) gauge theory interacting with a real scalar multiplet in the adjoint representation. We show that dimensional transmutation can occur, spontaneously breaking SO(10) to SU(5)⊗U(1), while inducing the Planck mass and a positive cosmological constant, all proportional to the same scale v. All mass ratios are functions of the values of coupling constants at that scale. Below this scale (at which the Big Bang may occur), the model takes the usual form of Einstein-Hilbert gravity in de Sitter space plus calculable corrections. We show that there exist regions of parameter space in which the breaking results in a local minimum of the effective action giving a positive dilaton (mass){sup 2} from two-loop corrections associated with the conformal anomaly. Furthermore, unlike the singlet case we considered previously, some minima lie within the basin of attraction of the ultraviolet fixed point. Moreover, the asymptotic behavior of the coupling constants also lie within the range of convergence of the Euclidean path integral, so there is hope that there will be candidates for sensible vacua. Although open questions remain concerning unitarity of all such renormalizable models of gravity, it is not obvious that, in curved backgrounds such as those considered here, unitarity is violated. In any case, any violation that may remain will be suppressed by inverse powers of the reduced Planck mass.

  3. SU(5)×U(1)X grand unification with minimal seesaw and Z‧-portal dark matter

    Science.gov (United States)

    Okada, Nobuchika; Okada, Satomi; Raut, Digesh

    2018-05-01

    We propose a grand unified SU (5) × U(1)X model, where the standard SU(5) grand unified theory is supplemented by minimal seesaw and a right-handed neutrino dark matter with an introduction of a global Z2-parity. In the presence of three right-handed neutrinos (RHNs), the model is free from all gauge and mixed-gravitational anomalies. The SU(5) symmetry is broken into the Standard Model (SM) gauge group at MGUT ≃ 4 ×1016GeV in the standard manner, while the U(1)X symmetry breaking occurs at the TeV scale, which generates the TeV-scale mass of the U(1)X gauge boson (Z‧ boson) and the three Majorana RHNs. A unique Z2-odd RHN is stable and serves as the dark matter (DM) in the present Universe, while the remaining two RHNs work to generate the SM neutrino masses through the minimal seesaw. We investigate the Z‧-portal RHN DM scenario in this model context. We find that the constraints from the DM relic abundance, and the Z‧ boson search at the Large Hadron Collider (LHC), and the perturbativity bound on the U(1)X gauge coupling are complementary to narrow down the allowed parameter region in the range of 3.0 ≤mZ‧ [TeV ] ≤ 9.2 for the Z‧ boson mass. The allowed region for mZ‧ ≤ 5TeV will be fully covered by the future LHC experiments. We also briefly discuss the successful implementation of Baryogenesis and cosmological inflation scenarios in the present model.

  4. Theoretical high-energy physics. Progress report, 1 January-31 December 1985

    International Nuclear Information System (INIS)

    Feldman, D.; Fried, H.M.; Jevicki, A.; Kang, K.; Tan, C.I.

    1985-01-01

    This year's research has dealt with: one-loop structure of spontaneously broken gauge theories and the contraction of symmetry groups; continuum strong coupling approximations by infrared extraction; methods of approximating ordered exponentials; field theoretic methods for viscous Navier-Stokes fluid flow; discretization method to quantum gravity and string field theory; skyrmions and solitons in field theory; nonlinear sigma-models with Wess-Zumino type terms; a variety of grand unification models and family unification in grand unified theories; composite fermions; axions in superstring models; cosmological constraint on heavy particles; axion emissions in astrophysicial systems; calculability of flavor-mixings; a field theoretic understanding of the quantum Hall effect including scaling of effective theta-parameter for non-axionic explanation of strong CP invariance; correlation decay theorem at high temperature; axial anomaly in chirally invariant nonlocal lattice gauge theories; axial anomaly and index theorem for manifolds with boundary; nonperturbative aspect of lattice gauge theories; lattice QCD in large N limit; quantum fluctuations of matter fields; and pregeometric quantum lattice. 40 refs

  5. Right-handed neutrinos in F-theory compactifications

    International Nuclear Information System (INIS)

    Tatar, Radu; Tsuchiya, Yoichi; Watari, Taizan

    2009-01-01

    F-theory is one of the frameworks where up-type Yukawa couplings of SU(5) unified theories are naturally generated. As charged matter fields have localized zero modes in F-theory, a study of flavor structure could be easier in F-theory than in Heterotic string theory. In a study of flavor structure in the lepton sector, however, an important role is played by right-handed neutrinos, which are not charged under the SU(5) unified gauge group. It is therefore solicited to find out what right-handed neutrinos are in F-theory compactifications and how their Majorana mass terms are generated together with developing a theoretical framework where effective Yukawa couplings involving both SU(5)-neutral and charged fields can be calculated. We find that the complex structure moduli chiral multiplets of F-theory compactifications are good candidates to be right-handed neutrinos, and that their Majorana masses are automatically generated in flux compactifications. The mass scale is predicted to be somewhat below the GUT scale, which is in nice agreement with the Δm 2 of the atmospheric neutrino oscillation through the see-saw mechanism. We also discuss various scenarios of solving the dimension-4 proton decay problem in supersymmetric F-theory compactifications, along with considering the consequences of those scenarios in the nature of right-handed neutrinos.

  6. Introduction to gauge theories and unification

    International Nuclear Information System (INIS)

    Das, A.

    1990-01-01

    This paper contains the following lectures on gauge theories: basic notations; dimensional regularization; complex scalar field theory; scalar field theory; self-interacting scalar field theory; Noether's theorem; spontaneous symmetry breaking; dirac field theories; local symmetry; quantum electrodynamics; Higgs mechanism; non-Abelian symmetries; and Weinberg-Salam-Glashow theory

  7. Standard(-like) Model from an SO(12) Grand Unified Theory in six-dimensions with S2 extra-space

    International Nuclear Information System (INIS)

    Nomura, Takaaki; Sato, Joe

    2009-01-01

    We analyze a gauge-Higgs unification model which is based on a gauge theory defined on a six-dimensional spacetime with an S 2 extra-space. We impose a symmetry condition for a gauge field and non-trivial boundary conditions of the S 2 . We provide the scheme for constructing a four-dimensional theory from the six-dimensional gauge theory under these conditions. We then construct a concrete model based on an SO(12) gauge theory with fermions which lie in a 32 representation of SO(12), under the scheme. This model leads to a Standard Model(-like) gauge theory which has gauge symmetry SU(3)xSU(2) L xU(1) Y (xU(1) 2 ) and one generation of SM fermions, in four-dimensions. The Higgs sector of the model is also analyzed, and it is shown that the electroweak symmetry breaking and the prediction of W-boson and Higgs-boson masses are obtained

  8. Axion inflation in F-theory

    Energy Technology Data Exchange (ETDEWEB)

    Grimm, Thomas W.

    2014-12-12

    We study the dynamics of axion-like fields in F-theory and suggest that they can serve as inflatons in models of natural inflation. The axions arise from harmonic three-forms on the F-theory compactification space and parameterize a complex torus that varies over the geometric moduli space. In particular, this implies that the axion decay constants depend on the complex structure moduli that can be fixed by background fluxes. This might allow tuning them to be super-Planckian in a controlled way and allow for interesting single field inflationary models. We argue that this requires a localization of the three-forms near regions of strong string coupling, analogously to the reasoning that GUT physics requires the use of F-theory. These models can admit a tensor to scalar ratio r>0.1.

  9. Antigravity in F( R) and Brans-Dicke theories

    Science.gov (United States)

    Oikonomou, V. K.; Karagiannakis, N.

    2014-12-01

    We study antigravity in F( R)-theory originating scalar-tensor theories and also in Brans-Dicke models without cosmological constant. For the F( R) theory case, we obtain the Jordan frame antigravity scalar-tensor theory by using a variant of the Lagrange multipliers method and we numerically study the time dependent effective gravitational constant. As we shall demonstrate in detail by using some viable F( R) models, although the initial F( R) models have no antigravity, their scalar-tensor counterpart theories might or not have antigravity, a fact mainly depending on the parameter that characterizes antigravity. Similar results hold true in the Brans-Dicke model, which we also studied numerically. In addition, regarding the Brans-Dicke model we also found some analytic cosmological solutions. Since antigravity is an unwanted feature in gravitational theories, our findings suggest that in the case of F( R) theories, antigravity does not occur in the real world described by the F( R) theory, but might occur in the Jordan frame scalar-tensor counterpart of the F( R) theory, and this happens under certain circumstances. The central goal of our study is to present all different cases in which antigravity might occur in modified gravity models.

  10. Preface to a GUT (Grand Unified Theory)

    International Nuclear Information System (INIS)

    Honig, W.

    1982-01-01

    A Grand Unified Theory (GUT) is proposed exhibiting relativistic invariance and based on a physical model for vacuum space consisting of the superposition of oppositely charged continuous fluids. Models for the photon, electron, neutrino, proton, etc., consist of separate unique variations in the relative densities of the fluids and their flow patterns. This GUT is also based on the use of transfinite axiomatic number forms and on a concept of metrical relativity which hopefully reconciles the many logical dichotomies in and between Special Relativity and Quantum Mechanics. These ideas result in a number of experimental proposals and predicted results which appear to be underivable from present paradigms, first among which is a physical model for the hidden variable of Quantum Mechanics. It is on these features that attention should rest. (Auth.)

  11. Constraints on grand unified superstring theories

    International Nuclear Information System (INIS)

    Ellis, J.; Lopez, J.L.; Nanopoulos, D.V.; Houston Advanced Research Center

    1990-01-01

    We evaluate some constraints on the construction of grand unified superstring theories (GUSTs) using higher level Kac-Moody algebras on the world-sheet. In the most general formulation of the heterotic string in four dimensions, an analysis of the basic GUST model-building constraints, including a realistic hidden gauge group, reveals that there are no E 6 models and any SO(10) models can only exist at level-5. Also, any such SU(5) models can exist only for levels 4≤k≤19. These SO(10) and SU(5) models risk having many large, massless, phenomenologically troublesome representations. We also show that with a suitable hidden sector gauge group, it is possible to avoid free light fractionally charged particles, which are endemic to string derived models. We list all such groups and their representations for the flipped SU(5)xU(1) model. We conclude that a sufficiently binding hidden sector gauge group becomes a basic model-building constraint. (orig.)

  12. Renormalization effects in the SU(16) maximally gauged theory

    International Nuclear Information System (INIS)

    Mahdavi-Hezaveh, E.

    1981-03-01

    In the context of a quark-lepton unified gauge theory, when fermionic degrees of freedom are maximally gauged, several intermediate mass scales filling the grand plateau, between 10 2 Gev. and the grand unifying mass scale, M, may exist. In particular, when renormalization effects are taken into account for the SU(16) ''maximal'' gauge symmetry, [in which lepton number is regarded as the fourth color quantum number], it turns out that two intermediate stages governed by the symmetries G 2 =SU(8)sub(I) S SU(8)sub(II) X U(1)sub(F) and G 3 =SU(2)sub(L) X XU(2)sub(R) X SU(4)sub(C) can naturally coexist if Sin 2 theta (Msub(W))>1/6+5/9(α(Msub(W)/αsub(S)(Msub(W)). It is shown that these symmetries break down at a mass scale of the order of Msub(X) approximately equal to 10 4 -10 5 Gev. If neutral current phenomenology (or any other experiment) predicts Sin 2 theta (Msub(W))>0.206, then quark-lepton unification and left-right symmetry simultaneously break down at M approximately equal to 10 4 Gev. (at which αsub(C)(Msub(X) approximately equal to 0.041). It is then argued that apart from proton decay, n-anti n oscillation and neutrinoless double β decay processes, an accurate experimental value of Sin 2 theta (Msub(W)), to α 10 -4 accuracy) plays a crucial role in determining the possible existence of such intermediate stages. (author)

  13. [Theory of elementary particles studies in weak interaction and grand unification and studies in accelerator design

    International Nuclear Information System (INIS)

    1989-01-01

    This report discusses topics on: Rare B decay; Physics beyond the standard model; Intermittency; Relativistic heavy-ion collisions; Cross section for jet production in hadron collisions; Factorization; Determination of the parton distribution function; Left-right electroweak theories; and Supersymmetry at Lepton colliders

  14. New aspects of flavour model building in supersymmetric grand unification

    International Nuclear Information System (INIS)

    Spinrath, Martin

    2010-01-01

    We derive predictions for Yukawa coupling ratios within Grand Unified Theories generated from operators with mass dimension four and five. These relations are a characteristic property of unified flavour models and can reduce the large number of free parameters related to the flavour sector of the Standard Model. The Yukawa couplings of the down-type quarks and charged leptons are affected within supersymmetric models by tan β-enhanced threshold corrections which can be sizeable if tan β is large. In this case their careful inclusion in the renormalisation group evolution is mandatory. We analyse these corrections and give simple analytic expressions and numerical estimates for them. The threshold corrections sensitively depend on the soft supersymmetry breaking parameters. Especially, they determine the overall sign of the corrections and therefore if the affected Yukawa couplings are enhanced or suppressed. In the minimal supersymmetric extension of the Standard Model many free parameters are introduced by supersymmetry breaking about which we make some plausible assumptions in our first simplified approach. In a second, more sophisticated approach we use three common breaking schemes in which all the soft breaking parameters at the electroweak scale can be calculated from only a handful of parameters. Within the second approach, we apply various phenomenological constraints on the supersymmetric parameters and find in this way new viable Yukawa coupling relations, for example y μ /y s =9/2 or 6 or y τ /y b =3/2 in SU(5). Furthermore, we study a special class of quark mass matrix textures for small tan β where θ u 13 =θ d 13 =0. We derive sum rules for the quark mixing parameters and find a simple relation between the two phases δ u 12 and δ d 12 and the right unitarity triangle angle α which suggests a simple phase structure for the quark mass matrices where one matrix element is purely imaginary and the remaining ones are purely real. To complement

  15. Les représentations de la réunification allemande dans l’ex-Yougoslavie

    Directory of Open Access Journals (Sweden)

    Laurent Hassid

    2012-06-01

    Full Text Available La réunification allemande a été perçue de manière différente dans les États de l’ex-Yougoslavie. En Serbie, république la plus peuplée de la Fédération et où se trouve le pouvoir central, elle est crainte comme le symbole d’une possible désintégration. En Croatie et en Slovénie s’est ainsi répandue l’idée que « si l’Allemagne peut se réunifier, la Yougoslavie peut bien se désintégrer » (Entretien avec Vladimir Radomirovic, ancien rédacteur en chef du quotidien serbe Politika et fondateur en 2009 de Pistaljka, site Internet qui dénonce la corruption dans les Balkans - www.pistaljka.rs. Au risque de provoquer une crise au sein de la CEE, l’Allemagne a poussé les autres grandes puissances du continent, dont la France, à reconnaître rapidement les indépendances des deux républiques. Pour comprendre les différentes représentations de la réunification allemande dans les Balkans, il est nécessaire d’étudier également les perceptions de la chute du Mur de Berlin, un an plus tôt. Symbole d’un communisme qui n’est pas tombé partout dans l’ex-Yougoslavie à partir de 1991, il a néanmoins grandement participé à la désintégration de la Fédération. Vingt ans après, l’Allemagne reste un acteur majeur dans la région, mais a abandonné une partie de son influence économique et politique au profit de l’Union européenne, notamment à partir de l’introduction de l’euro qui prend la place du mark, ancienne devise de référence.

  16. Aspects of grand unification in higher dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Wingerter, A.

    2005-07-01

    We consider various aspects of string phenomenology in the context of heterotic orbifold constructions, where special emphasis is laid on the connection between GUT models in extra dimensions and their relation to string theory. We investigate orbifold models with more general structure than the Z{sub 3} orbifold, on which most of the past research had focused. The picture of the heterotic brane world which naturally emerges allows us to make contact to field theoretic orbifold constructions in five and six dimensions, which have recently attracted much attention. We present a classification scheme for inequivalent orbifold models and apply the results to the case of Z{sub 6}-II point group. We develop the mathematical background for a stringy Higgs mechanism which allows us to lower the rank of the gauge group in the higher dimensions, which cannot be achieved by contemporary orbifold constructions. We provide all the calculational methods needed to unambiguously identify the gauge symmetry and to construct the matter representations. For specific model constructions, we focus on two promising gauge groups, namely on SO(10) and E{sub 6}. In the latter case, we derive a GUT model in six dimensions which has a standard model like gauge symmetry SU(3) x SU (2) x U(1) x U(1)' in four dimensions, and discuss its embedding into string theory. (orig.)

  17. SU(5) unification with TeV-scale leptoquarks

    Energy Technology Data Exchange (ETDEWEB)

    Cox, Peter [Kavli Institute for the Physics and Mathematics of the Universe (WPI), UTIAS,The University of Tokyo, Kashiwa, Chiba, 277-8583 (Japan); Kusenko, Alexander [Department of Physics and Astronomy, University of California,Los Angeles, CA, 90095-1547 (United States); Kavli Institute for the Physics and Mathematics of the Universe (WPI), UTIAS,The University of Tokyo, Kashiwa, Chiba, 277-8583 (Japan); Sumensari, Olcyr [Laboratoire de Physique Théorique, CNRS, Université Paris-Sud, Université Paris-Saclay,Orsay, 91405 (France); Instituto de Física, Universidade de São Paulo,C.P. 66.318, São Paulo, 05315-970 (Brazil); Yanagida, Tsutomu T. [Kavli Institute for the Physics and Mathematics of the Universe (WPI), UTIAS,The University of Tokyo, Kashiwa, Chiba, 277-8583 (Japan)

    2017-03-07

    It was previously noted that SU(5) unification can be achieved via the simple addition of light scalar leptoquarks from two split 10 multiplets. We explore the parameter space of this model in detail and find that unification requires at least one leptoquark to have mass below ≈16 TeV. We point out that introducing splitting of the 24 allows the unification scale to be raised beyond 10{sup 16} GeV, while a U(1){sub PQ} symmetry can be imposed to forbid dangerous proton decay mediated by the light leptoquarks. The latest bounds from LHC searches are combined and we find that a leptoquark as light as 400 GeV is still permitted. Finally, we discuss the interesting possibility that the leptoquarks required for unification could also be responsible for the 2.6σ deviation observed in the ratio R{sub K} at LHCb.

  18. Preon Model and Family Replicated E_6 Unification

    Directory of Open Access Journals (Sweden)

    Larisa V. Laperashvili

    2008-02-01

    Full Text Available Previously we suggested a new preon model of composite quark-leptons and bosons with the 'flipped' $E_6imes widetilde{E_6}$ gauge symmetry group. We assumed that preons are dyons having both hyper-electric $g$ and hyper-magnetic $ilde g$ charges, and these preons-dyons are confined by hyper-magnetic strings which are an ${f N}=1$ supersymmetric non-Abelian flux tubes created by the condensation of spreons near the Planck scale. In the present paper we show that the existence of the three types of strings with tensions $T_k=k T_0$ $(k = 1,2,3$ producing three (and only three generations of composite quark-leptons, also provides three generations of composite gauge bosons ('hyper-gluons' and, as a consequence, predicts the family replicated $[E_6]^3$ unification at the scale $sim 10^{17}$ GeV. This group of unification has the possibility of breaking to the group of symmetry: $ [SU(3_C]^3imes [SU(2_L]^3imes [U(1_Y]^3 imes [U(1_{(B-L}]^3$ which undergoes the breakdown to the Standard Model at lower energies. Some predictive advantages of the family replicated gauge groups of symmetry are briefly discussed.

  19. The economic implications of Korean unification

    OpenAIRE

    Schmitz, Jonathan L.

    2002-01-01

    Approved for public release; distribution unlimited A major area of concern for Korean unification is the immense cost it will impose on South Korea. To lessen this burden, South Korea will need to initiate policy reforms that can ease the financial stress and repercussions of unification and create an integrated economic community with North Korea. At the same time, North Korea will need to create an environment that is conducive to economic integration by accepting and adopting reform me...

  20. Problems, puzzles and prospects: a personal perspective on present particle physics

    International Nuclear Information System (INIS)

    Politzer, H.D.

    1982-01-01

    As closing remarks to the meeting the author gives his personal perspective on a number of issues in Grand Unification. These include: gravity, particle structure, QCD and possible experimental tests of theory

  1. Structural convergence under reversible and irreversible monetary unification

    NARCIS (Netherlands)

    Beetsma, R.M.W.J.; Jensen, H.

    2003-01-01

    We explore endogenous monetary unification in the context of a model in which a country with serious structural distortions (and, hence, high inflation) is admitted into a monetary union once its economic structure has converged sufficiently towards that of the existing participants. If unification

  2. Structural convergence under reversible and irreversible monetary unification

    NARCIS (Netherlands)

    Beetsma, R.M.W.J.; Jensen, H.

    1999-01-01

    We explore endogenous monetary unification in the context of a model in which a country with serious structural distortions (and, hence, high inflation) is admitted into a monetary union once its economic structure has converged sufficiently towards that of the existing participants. If unification

  3. Restrictions on two Higgs doublet models and CP violation at the unification scale

    International Nuclear Information System (INIS)

    Athanasiu, G.G.

    1987-04-01

    Bounds on charged Higgs masses and couplings in models with two Higgs doublets are examined that came from CP violation in the neutral K system. Bounds on charged Higgs masses and couplings in two Higgs doublet models are also obtained from their effects on neutral-B-meson mixing. The bounds are found to be comparable to those obtained with additional assumptions from the neutral K system. The three generation phase invariant measure of CP violation is shown to satisfy a simple and solvable renormalization group equation. Its value is seen to fall by four to eight orders of magnitude between the weak and grand unification scales in the standard model, as well as in its two Higgs and supersymmetric extensions

  4. f(R) gravity and chameleon theories

    International Nuclear Information System (INIS)

    Brax, Philippe; Bruck, Carsten van de; Davis, Anne-Christine; Shaw, Douglas J.

    2008-01-01

    We analyze f(R) modifications of Einstein's gravity as dark energy models in the light of their connection with chameleon theories. Formulated as scalar-tensor theories, the f(R) theories imply the existence of a strong coupling of the scalar field to matter. This would violate all experimental gravitational tests on deviations from Newton's law. Fortunately, the existence of a matter dependent mass and a thin-shell effect allows one to alleviate these constraints. The thin-shell condition also implies strong restrictions on the cosmological dynamics of the f(R) theories. As a consequence, we find that the equation of state of dark energy is constrained to be extremely close to -1 in the recent past. We also examine the potential effects of f(R) theories in the context of the Eoet-wash experiments. We show that the requirement of a thin shell for the test bodies is not enough to guarantee a null result on deviations from Newton's law. As long as dark energy accounts for a sizeable fraction of the total energy density of the Universe, the constraints that we deduce also forbid any measurable deviation of the dark energy equation of state from -1. All in all, we find that both cosmological and laboratory tests imply that f(R) models are almost coincident with a ΛCDM model at the background level.

  5. L’origine de l’emploi de la forme analogique grande : concordance de genre ou identification du référent ?

    OpenAIRE

    Xia Haoyu Irene; Ranson Diana L.

    2016-01-01

    L’objectif de la présente étude est de déterminer les raisons pour lesquelles un auteur du XVIe siècle aurait choisi la nouvelle forme analogique grande plutôt que la forme épicène grand. L’étude est basée sur un corpus de 1341 occurrences de cet adjectif au féminin dans 17 textes de cinq auteurs. L’hypothèse de l’identification du référent propose qu’un auteur aurait choisi cette forme pour indiquer clairement qu’elle modifie un substantif féminin et assurer ainsi le lien entre l’adjectif et...

  6. Some speculations on a causal unification of relativity, gravitation, and quantum mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Buonomano, V; Engel, A [Universidade Estadual de Campinas (Brazil). Instituto de Matematica

    1976-03-01

    Some speculations on a causal model that could provide a common conceptual foundation for relativity, gravitation, and quantum mechanics are presented. The present approach is a unification of three theories, the first being the repulsive theory of gravitational forces first proposed by Lesage who attempted to explain gravitational forces from the principle of conservation of momentum of the hypothetical particles gravitons. The second of these theories is the Brownian motion theory of quantum mechanics or stochastic mechanics, which treats the nondeterministic nature of quantum mechanics as being due to a Brownian motion of all objects. This Brownian motion being caused by the statistical variation in the graviton flux. The above two theories are unified in this article with the causal theory of special relativity. The Big Bang theory of the creation of the Universe is assumed. An experimental test is proposed.

  7. From F/M-theory to K-theory and back

    International Nuclear Information System (INIS)

    Garcia-Etxebarria, Inaki; Uranga, Angel M.

    2006-01-01

    We consider discrete K-theory tadpole cancellation conditions in type IIB orientifolds with magnetised 7-branes. Cancellation of K-theory charge constrains the choices of world-volume magnetic fluxes on the latter. We describe the F-/M-theory lift of these configurations, where 7-branes are encoded in the geometry of an elliptic fibration, and their magnetic quanta correspond to supergravity 4-form field strength fluxes. In a K3 compactification example, we show that standard quantization of 4-form fluxes as integer cohomology classes in K3 automatically implies the K-theory charge cancellation constraints on the 7-brane worldvolume magnetic fluxes in string theory (as well as new previously unnoticed discrete constraints, which we also interpret). Finally, we show that flux quantization in F-/M-theory implies that 7-brane world-volume flux quantization conditions are modified in the presence of 3-form fluxes

  8. From F/M-theory to K-theory and back

    CERN Document Server

    Garcia-Etxebarria, I; Garcia-Etxebarria, Inaki; Uranga, Angel M.

    2006-01-01

    We consider discrete K-theory tadpole cancellation conditions in type IIB orientifolds with magnetised 7-branes. Cancellation of K-theory charge constrains the choices of world-volume magnetic fluxes on the latter. We describe the F-/M-theory lift of these configurations, where 7-branes are encoded in the geometry of an elliptic fibration, and their magnetic quanta correspond to supergravity 4-form field strength fluxes. In a K3 compactification example, we show that standard quantization of 4-form fluxes as integer cohomology classes in K3 automatically implies the K-theory charge cancellation constraints on the 7-brane worldvolume magnetic fluxes in string theory (as well as new previously unnoticed discrete constraints, which we also interpret). Finally, we show that flux quantization in F-/M-theory implies that 7-brane world-volume flux quantization conditions are modified in the presence of 3-form fluxes.

  9. Supersymmetry: Theory

    International Nuclear Information System (INIS)

    Peskin, M.E.

    1996-03-01

    If supersymmetric particles are discovered at high-energy colliders, what can one hope to learn about them? In principle, the properties of supersymmetric particles can give a window into the physics of grand unification, or of other aspects of interactions at very short distances. In this article, the author sketches out a systematic program for the experimental study of supersymmetric particles and point out the essential role that e + e - linear colliders will play in this investigation

  10. Hidden SUSY from precision gauge unification

    Energy Technology Data Exchange (ETDEWEB)

    Krippendorf, Sven; Nilles, Hans Peter [Bonn Univ. (Germany). Bethe Center for Theoretical Physics; Bonn Univ. (Germany). Physikalisches Inst.; Ratz, Michael [Technische Univ. Muenchen, Garching (Germany). Physik-Department; Winkler, Martin Wolfgang [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2013-06-15

    We revisit the implications of naturalness and gauge unification in the MSSM. We find that precision unification of the couplings in connection with a small {mu} parameter requires a highly compressed gaugino pattern as it is realized in mirage mediation. Due to the small mass difference between gluino and LSP, collider limits on the gluino mass are drastically relaxed. Without further assumptions, the relic density of the LSP is very close to the observed dark matter density due to coannihilation effects.

  11. Hidden SUSY from precision gauge unification

    International Nuclear Information System (INIS)

    Krippendorf, Sven; Nilles, Hans Peter

    2013-06-01

    We revisit the implications of naturalness and gauge unification in the MSSM. We find that precision unification of the couplings in connection with a small μ parameter requires a highly compressed gaugino pattern as it is realized in mirage mediation. Due to the small mass difference between gluino and LSP, collider limits on the gluino mass are drastically relaxed. Without further assumptions, the relic density of the LSP is very close to the observed dark matter density due to coannihilation effects.

  12. Profumo di SUSY: Suggestive Correlations in the ATLAS and CMS High Jet Multiplicity Data

    CERN Document Server

    Li, Tianjun; Nanopoulos, Dimitri V; Walker, Joel W

    2011-01-01

    We present persistently amassing evidence that the CMS and ATLAS Collaborations may indeed be already registering supersymmetry events at the Large Hadron Collider (LHC). Our analysis is performed in the context of a highly phenomenologically favorable model named No-Scale F-SU(5), which represents the unification of the F-lipped SU(5) Grand Unified Theory (GUT), two pairs of hypothetical TeV-scale vector-like supersymmetric multiplets derived out of F-Theory, and the dynamically established boundary conditions of No-Scale supergravity. We document highly suggestive correlations between the first inverse femtobarn of observations by CMS and ATLAS, where seductive excesses in multijet events, particularly those with nine or more jets, are unambiguously accounted for by a precision Monte-Carlo simulation of the F-SU(5) model space. This intimate correspondence is optimized by a unified gaugino mass in the neighborhood of M_{1/2}=518 GeV. We supplement this analysis by extrapolating for the expected data profile...

  13. The Proactive Grand Strategy for Consensual and Peaceful Korean Unification

    Science.gov (United States)

    2007-03-01

    previous revisionists―I. F. Stone and Karunakar Gupta. I. F. Stone is the first scholar to claim that South Korea provoked North Korea. Leo Huberman and...Longman, 2001), 39. 20 Leo Huberman and Paul M. Sweezy, “Publisher’s Foreword,” in I.F. Stone, The Hidden History of the Korean War (New York...be a sea of fire. Mr. Song, it will probably be difficult for you to survive.”167 Seoul is only 25 miles away from the DMZ and the North Korean

  14. Low mass-scale parity restoration in expanded gauge theories

    International Nuclear Information System (INIS)

    Rajpoot, S.

    1982-07-01

    It is shown that schemes of grand unification with SU(2n) 4 gauge symmetry permit the embedding of the left-right symmetric SU(2)sub(L)xSU(2)sub(R)xU(1)xSU(3) intermediate symmetry at relatively low energies (between 250 GeV and 1 TeV) as well as allowing light unification mass-scales ( 5 TeV) if n>=3 for values of the weak angle Sin 2 thetasub(W) and the strong coupling αsub(s) in the ranges 0.20 2 thetasub(W)<=0.25, 0.10<=αsub(s)<=0.15. (author)

  15. F-theory and 2d (0,2) theories

    Energy Technology Data Exchange (ETDEWEB)

    Schäfer-Nameki, Sakura [Department of Mathematics, King’s College London, The Strand, London WC2R 2LS (United Kingdom); Weigand, Timo [Institut für Theoretische Physik, Ruprecht-Karls-Universität,Philosophenweg 19, 69120 Heidelberg (Germany)

    2016-05-11

    F-theory compactified on singular, elliptically fibered Calabi-Yau five-folds gives rise to two-dimensional gauge theories preserving N=(0,2) supersymmetry. In this paper we initiate the study of such compactifications and determine the dictionary between the geometric data of the elliptic fibration and the 2d gauge theory such as the matter content in terms of (0,2) superfields and their supersymmetric couplings. We study this setup both from a gauge-theoretic point of view, in terms of the partially twisted 7-brane theory, and provide a global geometric description based on the structure of the elliptic fibration and its singularities. Global consistency conditions are determined and checked against the dual M-theory compactification to one dimension. This includes a discussion of gauge anomalies, the structure of the Green-Schwarz terms and the Chern-Simons couplings in the dual M-theory supersymmetric quantum mechanics. Furthermore, by interpreting the resulting 2d (0,2) theories as heterotic worldsheet theories, we propose a correspondence between the geometric data of elliptically fibered Calabi-Yau five-folds and the target space of a heterotic gauged linear sigma-model (GLSM). In particular the correspondence between the Landau-Ginsburg and sigma-model phase of a 2d (0,2) GLSM is realized via different T-branes or gluing data in F-theory.

  16. Dark matter from unification

    DEFF Research Database (Denmark)

    Kainulainen, Kimmo; Tuominen, Kimmo; Virkajärvi, Jussi Tuomas

    2013-01-01

    We consider a minimal extension of the Standard Model (SM), which leads to unification of the SM coupling constants, breaks electroweak symmetry dynamically by a new strongly coupled sector and leads to novel dark matter candidates. In this model, the coupling constant unification requires...... eigenstates of this sector and determine the resulting relic density. The results are constrained by available data from colliders and direct and indirect dark matter experiments. We find the model viable and outline briefly future research directions....... the existence of electroweak triplet and doublet fermions singlet under QCD and new strong dynamics underlying the Higgs sector. Among these new matter fields and a new right handed neutrino, we consider the mass and mixing patterns of the neutral states. We argue for a symmetry stabilizing the lightest mass...

  17. The Metaphysical and Ontological Symbolism of Total Gravitational ...

    African Journals Online (AJOL)

    Having laid a firm foundation in SPACETIME for a detailed analysis of total gravitational collapse, by linking Einstein's Special Theory of Relativity (STR) to the General Theory (GTR) in the context of the Quantum Principle and within the all-embracing framework of GUT (the Grande Unification Theory), we proceed with an ...

  18. The minimal GUT with inflaton and dark matter unification

    Science.gov (United States)

    Chen, Heng-Yu; Gogoladze, Ilia; Hu, Shan; Li, Tianjun; Wu, Lina

    2018-01-01

    Giving up the solutions to the fine-tuning problems, we propose the non-supersymmetric flipped SU(5)× U(1)_X model based on the minimal particle content principle, which can be constructed from the four-dimensional SO(10) models, five-dimensional orbifold SO(10) models, and local F-theory SO(10) models. To achieve gauge coupling unification, we introduce one pair of vector-like fermions, which form a complete SU(5)× U(1)_X representation. The proton lifetime is around 5× 10^{35} years, neutrino masses and mixing can be explained via the seesaw mechanism, baryon asymmetry can be generated via leptogenesis, and the vacuum stability problem can be solved as well. In particular, we propose that inflaton and dark matter particles can be unified to a real scalar field with Z_2 symmetry, which is not an axion and does not have the non-minimal coupling to gravity. Such a kind of scenarios can be applied to the generic scalar dark matter models. Also, we find that the vector-like particle corrections to the B_s^0 masses might be about 6.6%, while their corrections to the K^0 and B_d^0 masses are negligible.

  19. The minimal GUT with inflaton and dark matter unification

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Heng-Yu; Gogoladze, Ilia [University of Delaware, Department of Physics and Astronomy, Bartol Research Institute, Newark, DE (United States); Hu, Shan [Hubei University, Department of Physics, Faculty of Physics and Electronic Sciences, Wuhan (China); Li, Tianjun [Chinese Academy of Sciences, Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Beijing (China); University of Chinese Academy of Sciences, School of Physical Sciences, Beijing (China); Wu, Lina [Chinese Academy of Sciences, Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Beijing (China); University of Electronic Science and Technology of China, School of Physical Electronics, Chengdu (China)

    2018-01-15

    Giving up the solutions to the fine-tuning problems, we propose the non-supersymmetric flipped SU(5) x U(1){sub X} model based on the minimal particle content principle, which can be constructed from the four-dimensional SO(10) models, five-dimensional orbifold SO(10) models, and local F-theory SO(10) models. To achieve gauge coupling unification, we introduce one pair of vector-like fermions, which form a complete SU(5) x U(1){sub X} representation. The proton lifetime is around 5 x 10{sup 35} years, neutrino masses and mixing can be explained via the seesaw mechanism, baryon asymmetry can be generated via leptogenesis, and the vacuum stability problem can be solved as well. In particular, we propose that inflaton and dark matter particles can be unified to a real scalar field with Z{sub 2} symmetry, which is not an axion and does not have the non-minimal coupling to gravity. Such a kind of scenarios can be applied to the generic scalar dark matter models. Also, we find that the vector-like particle corrections to the B{sub s}{sup 0} masses might be about 6.6%, while their corrections to the K{sup 0} and B{sub d}{sup 0} masses are negligible. (orig.)

  20. New aspects of flavour model building in supersymmetric grand unification

    Energy Technology Data Exchange (ETDEWEB)

    Spinrath, Martin

    2010-05-19

    We derive predictions for Yukawa coupling ratios within Grand Unified Theories generated from operators with mass dimension four and five. These relations are a characteristic property of unified flavour models and can reduce the large number of free parameters related to the flavour sector of the Standard Model. The Yukawa couplings of the down-type quarks and charged leptons are affected within supersymmetric models by tan {beta}-enhanced threshold corrections which can be sizeable if tan {beta} is large. In this case their careful inclusion in the renormalisation group evolution is mandatory. We analyse these corrections and give simple analytic expressions and numerical estimates for them. The threshold corrections sensitively depend on the soft supersymmetry breaking parameters. Especially, they determine the overall sign of the corrections and therefore if the affected Yukawa couplings are enhanced or suppressed. In the minimal supersymmetric extension of the Standard Model many free parameters are introduced by supersymmetry breaking about which we make some plausible assumptions in our first simplified approach. In a second, more sophisticated approach we use three common breaking schemes in which all the soft breaking parameters at the electroweak scale can be calculated from only a handful of parameters. Within the second approach, we apply various phenomenological constraints on the supersymmetric parameters and find in this way new viable Yukawa coupling relations, for example y{sub {mu}}/y{sub s}=9/2 or 6 or y{sub {tau}}/y{sub b}=3/2 in SU(5). Furthermore, we study a special class of quark mass matrix textures for small tan {beta} where {theta}{sup u}{sub 13}={theta}{sup d}{sub 13}=0. We derive sum rules for the quark mixing parameters and find a simple relation between the two phases {delta}{sup u}{sub 12} and {delta}{sup d}{sub 12} and the right unitarity triangle angle {alpha} which suggests a simple phase structure for the quark mass matrices where

  1. Superunification

    International Nuclear Information System (INIS)

    Ellis, J.; Zumino, B.; Gaillard, M.K.

    1981-09-01

    We explore scenarios for exploiting supersymmetry in unified field theories. Supersymmetry must be broken at some level, and we discuss theories with different supergaps. In particular we review the possibility that the hierarchy problem may be alleviated in simply supersymmetric grand unified theories, thanks to certain non-renormalization theorems. Supersymmetric grand unified theories are not truly unified since the supersymmetry generators do not carry internal quantum numbers and gravity is not included. We therefore favour unification in extended supergravity theories, and analize possible schemes of this type, including the possibility that one supersymmetry is retained down to low energies in the form of a supersymmetric GUT. A major problem of unification in extended supergravity theories is the disposal of unwanted helicity states, and we propose some new ideas for achieving this. Our favoured approach postulates the existence in the physical spectrum of infinite-dimensional unitary representations of the noncompact symmetry groups of extended supergravities. Such representations could enable the unwanted helicity states to be paired off, leaving a desirable spectrum of states with masses much less than the Planck mass

  2. Book review: F. Azouvi, Le Mythe du grand silence: Auschwitz, les Français, la mémoire

    OpenAIRE

    Cavaletto , Andrea

    2014-01-01

    International audience; Review of: F. Azouvi, "Le Mythe du grand silence: Auschwitz, les Français, la mémoire", Fayard, 2012. Journal of Interdisciplinary History of Ideas, vol.2, n.4, December 2013

  3. Gauge-Higgs unification with broken flavour symmetry

    International Nuclear Information System (INIS)

    Olschewsky, M.

    2007-05-01

    We study a five-dimensional Gauge-Higgs unification model on the orbifold S 1 /Z 2 based on the extended standard model (SM) gauge group SU(2) L x U(1) Y x SO(3) F . The group SO(3) F is treated as a chiral gauged flavour symmetry. Electroweak-, flavour- and Higgs interactions are unified in one single gauge group SU(7). The unified gauge group SU(7) is broken down to SU(2) L x U(1) Y x SO(3) F by orbifolding and imposing Dirichlet and Neumann boundary conditions. The compactification scale of the theory is O(1) TeV. Furthermore, the orbifold S 1 /Z 2 is put on a lattice. This setting gives a well-defined staring point for renormalisation group (RG) transformations. As a result of the RG-flow, the bulk is integrated out and the extra dimension will consist of only two points: the orbifold fixed points. The model obtained this way is called an effective bilayered transverse lattice model. Parallel transporters (PT) in the extra dimension become nonunitary as a result of the blockspin transformations. In addition, a Higgs potential V(Φ) emerges naturally. The PTs can be written as a product e A y e η e A y of unitary factors e A y and a selfadjoint factor e η . The reduction 48 → 35 + 6 + anti 6 + 1 of the adjoint representation of SU(7) with respect to SU(6) contains SU(2) L x U(1) Y x SO(3) F leads to three SU(2) L Higgs doublets: one for the first, one for the second and one for the third generation. Their zero modes serve as a substitute for the SM Higgs. When the extended SM gauge group SU(2) L x U(1) Y x SO(3) F is spontaneously broken down to U(1) em , an exponential gauge boson mass splitting occurs naturally. At a first step SU(2) L x U(1) Y x SO(3) F is broken to SU(2) L x U(1) Y by VEVs for the selfadjoint factor e η . This breaking leads to masses of flavour changing SO(3) F gauge bosons much above the compactification scale. Such a behaviour has no counterpart within the customary approximation scheme of an ordinary orbifold theory. This way tree

  4. Possible antigravity regions in F(R) theory?

    Energy Technology Data Exchange (ETDEWEB)

    Bamba, Kazuharu, E-mail: bamba@kmi.nagoya-u.ac.jp [Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University, Nagoya 464-8602 (Japan); Nojiri, Shin' ichi, E-mail: nojiri@phys.nagoya-u.ac.jp [Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University, Nagoya 464-8602 (Japan); Department of Physics, Nagoya University, Nagoya 464-8602 (Japan); Odintsov, Sergei D., E-mail: odintsov@ieec.uab.es [Department of Physics, Nagoya University, Nagoya 464-8602 (Japan); Instituciò Catalana de Recerca i Estudis Avançats (ICREA), Barcelona (Spain); Institut de Ciencies de l' Espai (CSIC-IEEC), Campus UAB, Facultat de Ciencies, Torre C5-Par-2a pl, E-08193 Bellaterra (Barcelona) (Spain); Tomsk State Pedagogical University, Kievskaya Avenue, 60, 634061, Tomsk (Russian Federation); Sáez-Gómez, Diego, E-mail: diego.saezgomez@uct.ac.za [Astrophysics, Cosmology and Gravity Centre (ACGC) and Department of Mathematics and Applied Mathematics, University of Cape Town, Rondebosch 7701, Cape Town (South Africa); Fisika Teorikoaren eta Zientziaren Historia Saila, Zientzia eta Teknologia Fakultatea, Euskal Herriko Unibertsitatea, 644 Posta Kutxatila, 48080 Bilbao (Spain)

    2014-03-07

    We construct an F(R) gravity theory corresponding to the Weyl invariant two scalar field theory. We investigate whether such F(R) gravity can have the antigravity regions where the Weyl curvature invariant does not diverge at the Big Bang and Big Crunch singularities. It is revealed that the divergence cannot be evaded completely but can be much milder than that in the original Weyl invariant two scalar field theory.

  5. Possible antigravity regions in F(R) theory?

    Science.gov (United States)

    Bamba, Kazuharu; Nojiri, Shin'ichi; Odintsov, Sergei D.; Sáez-Gómez, Diego

    2014-03-01

    We construct an F(R) gravity theory corresponding to the Weyl invariant two scalar field theory. We investigate whether such F(R) gravity can have the antigravity regions where the Weyl curvature invariant does not diverge at the Big Bang and Big Crunch singularities. It is revealed that the divergence cannot be evaded completely but can be much milder than that in the original Weyl invariant two scalar field theory.

  6. Possible antigravity regions in F(R) theory?

    International Nuclear Information System (INIS)

    Bamba, Kazuharu; Nojiri, Shin'ichi; Odintsov, Sergei D.; Sáez-Gómez, Diego

    2014-01-01

    We construct an F(R) gravity theory corresponding to the Weyl invariant two scalar field theory. We investigate whether such F(R) gravity can have the antigravity regions where the Weyl curvature invariant does not diverge at the Big Bang and Big Crunch singularities. It is revealed that the divergence cannot be evaded completely but can be much milder than that in the original Weyl invariant two scalar field theory.

  7. Discrete structures in F-theory compactifications

    Energy Technology Data Exchange (ETDEWEB)

    Till, Oskar

    2016-05-04

    In this thesis we study global properties of F-theory compactifications on elliptically and genus-one fibered Calabi-Yau varieties. This is motivated by phenomenological considerations as well as by the need for a deeper understanding of the set of consistent F-theory vacua. The global geometric features arise from discrete and arithmetic structures in the torus fiber and can be studied in detail for fibrations over generic bases. In the case of elliptic fibrations we study the role of the torsion subgroup of the Mordell-Weil group of sections in four dimensional compactifications. We show how the existence of a torsional section restricts the admissible matter representations in the theory. This is shown to be equivalent to inducing a non-trivial fundamental group of the gauge group. Compactifying F-theory on genus-one fibrations with multisections gives rise to discrete selection rules. In field theory the discrete symmetry is a broken U(1) symmetry. In the geometry the higgsing corresponds to a conifold transition. We explain in detail the origin of the discrete symmetry from two different M-theory phases and put the result into the context of torsion homology. Finally we systematically construct consistent gauge fluxes on genus-one fibrations and show that these induce an anomaly free chiral spectrum.

  8. Dirac gauginos, gauge mediation and unification

    Energy Technology Data Exchange (ETDEWEB)

    Benakli, K. [UPMC Univ. Paris 06 (France). Laboratoire de Physique Theorique et Hautes Energies, CNRS; Goodsell, M.D. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2010-03-15

    We investigate the building of models with Dirac gauginos and perturbative gauge coupling unification. Here, in contrast to the MSSM, additional fields are required for unification, and these can naturally play the role of the messengers of supersymmetry breaking. We present a framework within which such models can be constructed, including the constraints that the messenger sector must satisfy; and the renormalisation group equations for the soft parameters, which differ from those of the MSSM. For illustration, we provide the spectrum at the electroweak scale for explicit models whose gauge couplings unify at the scale predicted by heterotic strings. (orig.)

  9. Dirac Gauginos, Gauge Mediation and Unification

    CERN Document Server

    Benakli, K

    2010-01-01

    We investigate the building of models with Dirac gauginos and perturbative gauge coupling unification. Here, in contrast to the MSSM, additional fields are required for unification, and these can naturally play the role of the messengers of supersymmetry breaking. We present a framework within which such models can be constructed, including the constraints that the messenger sector must satisfy; and the renormalisation group equations for the soft parameters, which differ from those of the MSSM. For illustration, we provide the spectrum at the electroweak scale for explicit models whose gauge couplings unify at the scale predicted by heterotic strings.

  10. Dirac gauginos, gauge mediation and unification

    International Nuclear Information System (INIS)

    Benakli, K.

    2010-03-01

    We investigate the building of models with Dirac gauginos and perturbative gauge coupling unification. Here, in contrast to the MSSM, additional fields are required for unification, and these can naturally play the role of the messengers of supersymmetry breaking. We present a framework within which such models can be constructed, including the constraints that the messenger sector must satisfy; and the renormalisation group equations for the soft parameters, which differ from those of the MSSM. For illustration, we provide the spectrum at the electroweak scale for explicit models whose gauge couplings unify at the scale predicted by heterotic strings. (orig.)

  11. China’s unification: Myth or reality?

    Directory of Open Access Journals (Sweden)

    Estrada Mario Arturo Ruiz

    2014-01-01

    Full Text Available This paper evaluates the prospect of a possible unification between People’s Republic of China (Mainland China and Republic of China (Taiwan from a multi-dimensional perspective which encompasses the political, social, economic, and technological dimensions. The underlying idea is to evaluate the possibility of a partial or total reunification between the two countries in a more comprehensive way than just assessing the economic costs and benefits. Our evaluation is based on the application of the GDRI-Model, which looks at unification and regional integration simultaneously from the political, economic, social and technological perspectives.

  12. ACADEMIC TRAINING LECTURE

    CERN Multimedia

    Academic Training; Tel. 73127

    2001-01-01

    2, 3, 4, 5 and 6 April REGULAR LECTURE PROGRAMME From 11:00 hrs - Main Auditorium bldg. 500 New Developments in Supersymmetry S. Raby / CERN-TH Introduction to supersymmetric grand unified theories. An introduction to the MSSM and different mechanisms for supersymmetry breaking. Then the details of SU(5) and SO(10) unification, the new gauge sector beyond the standard model, representations of quarks and leptons. Gauge and Yukawa coupling unification and some predictions.

  13. Pramana – Journal of Physics | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    pp 223-229 Special: Supersymmetric Unified Theories and Higgs Physics. Prospects of experimentally reachable beyond Standard Model physics in inverse see-saw motivated SO(10) GUT · Ram Lal Awasthi · More Details Abstract Fulltext PDF. The grand unification theories based on SO(10) gauge group have been at the ...

  14. What energy does gravity unite with grand unified theories in the early universe

    International Nuclear Information System (INIS)

    Sivaram, C.

    1987-01-01

    Unification of gravity with GUTs is usually expected at the Planck energy E/sub PI/ ∼ 10 19 GeV. However, the vastly different values of the two couplings at E/sub PI/ (α/sub GUT/ E/sub PI/ with a single dimensionless coupling constant (α/sub U/ << 1) and described by a scale-invariant action quadratic in the Weyl curvature (with Yang-Mills fields). Breaking of scale invariance at E/sub PI/ then separates the interactions into gravity, now described by a Hilbert action with a dimensional G and GUTs with a dimensionless α/sub GUT/ and YM action. Problems with Klein-Kaluza unification of gravity with GUTs are also discussed in this context

  15. Softening the supersymmetric flavor problem in orbifold grand unified theories

    International Nuclear Information System (INIS)

    Kajiyama, Yuji; Terao, Haruhiko; Kubo, Jisuke

    2004-01-01

    The infrared attractive force of the bulk gauge interactions is applied to soften the supersymmetric flavor problem in the orbifold SU(5) grand unified theory of Kawamura. Then this force aligns in the infrared regime the soft supersymmetry breaking terms out of their anarchical disorder at a fundamental scale, in such a way that flavor-changing neutral currents as well as dangerous CP-violating phases are suppressed at low energies. It is found that this dynamical alignment is sufficiently good compared with the current experimental bounds, as long as the diagonalization matrices of the Yukawa couplings are CKM-like

  16. Addendum to 'Reconciling grand unification with strings by anisotropic compactifications'

    International Nuclear Information System (INIS)

    Dundee, Ben; Raby, Stuart; Wingerter, Akin

    2009-01-01

    In this brief addendum, we clarify a point which we left unaddressed in a previous publication [Phys. Rev. D 78, 066006 (2008)]. In particular, we show that a specific vacuum configuration constructed in one of our models satisfies the condition D=0. In the previous publication, we only showed F=0. Both D=0 and F=0 are necessary to ensure that supersymmetry survives to the weak scale.

  17. Five-brane superpotentials and heterotic/F-theory duality

    International Nuclear Information System (INIS)

    Grimm, Thomas W.; Ha, Tae-Won; Klemm, Albrecht; Klevers, Denis

    2010-01-01

    Under heterotic/F-theory duality it was argued that a wide class of heterotic five-branes is mapped into the geometry of an F-theory compactification manifold. In four-dimensional compactifications this identifies a five-brane wrapped on a curve in the base of an elliptically fibered Calabi-Yau threefold with a specific F-theory Calabi-Yau fourfold containing the blow-up of the five-brane curve. We argue that this duality can be reformulated by first constructing a non-Calabi-Yau heterotic threefold by blowing up the curve of the five-brane into a divisor with five-brane flux. Employing heterotic/F-theory duality this leads us to the construction of a Calabi-Yau fourfold and four-form flux. Moreover, we obtain an explicit map between the five-brane superpotential and an F-theory flux superpotential. The map of the open-closed deformation problem of a five-brane in a compact Calabi-Yau threefold into a deformation problem of complex structures on a dual Calabi-Yau fourfold with four-form flux provides a powerful tool to explicitly compute the five-brane superpotential.

  18. On the possibility of magnetic monopoles lighter than 1/α Msub(x) in grand unified theories

    International Nuclear Information System (INIS)

    Scott, D.M.

    1980-04-01

    It is argued that in special cases monopoles may have masses significantly less than 1/αMsub(x) where Msub(x) is the mass of the heaviest vector boson in the grand unified theory under consideration. (author)

  19. New ideas about unified field theory

    International Nuclear Information System (INIS)

    Gleiser, M.

    1986-01-01

    An outline of the physical concepts evolution is given from the ancient philosophers to the present time. With qualitative explanations about the meaning of the theories that is the milestones of these concepts evolution, it mentions the ideas which lead the studies to the conception of a unified field theory. Chronologically, it has brief information about the ideas of Laplace (mechanical determinism), Maxwell (the field concept), Einsten (the space-time structure), Heisenberg and Schroedinger (the quantum mechanics), Dirac (the relativistic quantum and the antiparticles), Gell-Mann (the quarks), Weinberg-Salam (Weak interactions and eletromagnetic unification), H. Georgi and S. Glashon (strong interactions plus Weinberg-Salam), Kaluza-Klein (a fifth space-time coordinate), and Zumino-Weiss (supersymmetry and supergravity). (G.D.F.) [pt

  20. Phase transition and thermodynamic geometry of f (R ) AdS black holes in the grand canonical ensemble

    Science.gov (United States)

    Li, Gu-Qiang; Mo, Jie-Xiong

    2016-06-01

    The phase transition of a four-dimensional charged AdS black hole solution in the R +f (R ) gravity with constant curvature is investigated in the grand canonical ensemble, where we find novel characteristics quite different from that in the canonical ensemble. There exists no critical point for T -S curve while in former research critical point was found for both the T -S curve and T -r+ curve when the electric charge of f (R ) black holes is kept fixed. Moreover, we derive the explicit expression for the specific heat, the analog of volume expansion coefficient and isothermal compressibility coefficient when the electric potential of f (R ) AdS black hole is fixed. The specific heat CΦ encounters a divergence when 0 b . This finding also differs from the result in the canonical ensemble, where there may be two, one or no divergence points for the specific heat CQ . To examine the phase structure newly found in the grand canonical ensemble, we appeal to the well-known thermodynamic geometry tools and derive the analytic expressions for both the Weinhold scalar curvature and Ruppeiner scalar curvature. It is shown that they diverge exactly where the specific heat CΦ diverges.

  1. Discovery of proton decay: A must for theory, a challenge for experiment

    Science.gov (United States)

    Pati, Jogesh C.

    2000-08-01

    It is noted that, but for one missing piece—proton decay—the evidence in support of grand unification is now strong. It includes: (i) the observed family-structure, (ii) the meeting of the gauge couplings, (iii) neutrino-oscillations, (iv) the intricate pattern of the masses and mixings of all fermions, including the neutrinos, and (v) the need for B-L as a generator, to implement baryogenesis. Taken together, these not only favor grand unification but in fact select out a particular route to such unification, based on the ideas of supersymmetry, SU(4)-color and left-right symmetry. Thus they point to the relevance of an effective string-unified G(224) or SO(10)-symmetry. A concrete proposal is presented, within a predictive SO(10)/G(224)-framework, that successfully describes the masses and mixings of all fermions, including the neutrinos—with eight predictions, all in agreement with observation. Within this framework, a systematic study of proton decay is carried out, which pays special attention to its dependence on the fermion masses, including the superheavy Majorana masses of the right-handed neutrinos. The study shows that a conservative upper limit on the proton lifetime is about (1/2-1)×1034yrs, with ν¯K+ being the dominant decay mode, and as a distinctive feature, μ+K0 being prominent. This in turn strongly suggests that an improvement in the current sensitivity by a factor of five to ten (compared to SuperK) ought to reveal proton decay. Otherwise some promising and remarkably successful ideas on unification would suffer a major setback.

  2. F-Theory - From Geometry to Physics and Back

    CERN Multimedia

    CERN. Geneva

    2017-01-01

    Compactifications of string theory have the potential to form a bridge between what we believe is a consistent quantum theory of gravity in 10 spacetime dimensions and observed physics in four dimensions. At the same time, beautiful results from mathematics, especially algebraic geometry, are directly linked to some of the key concepts in modern particle and quantum field theory. This theory colloquium will illustrate some of these ideas in the context of F-theory, which provides a non-perturbative formulation of a class of string compactifications in their geometric regime. Recent applications of F-theory range from very concrete suggestions to address known challenges in physics beyond the Standard Model to the 'physicalization of geometry' to the construction and investigations of strongly coupled quantum field theories in various dimensions. After reviewing examples of such applications we will conclude by demonstrating the close links between geometry and physics in F-theory via some new results on the r...

  3. Pattern of neutrino mixing in grand unified theories

    International Nuclear Information System (INIS)

    Milton, K.; Tanaka, K.

    1981-01-01

    It was found previously in SO(10) grand unified theories that if the neutrinos have a Dirac mass and a right-handed Majorana mass (approx. 10 15 GeV) but no left-handed Majorana mass, there is small ν/sub e/ mixing but ν/sub μ/ - ν/sub tau/ mixing can be substantial. This problem is reexamined on the basis of a formalism that assumes that the up, down, lepton, and neutrino mass matrices arise from a single complex 10 and a single 126 Higgs boson. This formalism determines the Majorana mass matrix in terms of quark mass matrices. Adopting three different sets of quark mass matrices that produce acceptable fermion mass ratios and Cabbibo mixing produces results consistent with the above; however, in the optimum case, ν/sub e/ - ν/sub μ/ mixing can be of the order of the Cabbibo angle

  4. Unification of Patrimonial Laws Governing International Trade

    DEFF Research Database (Denmark)

    Lando, Ole

    2016-01-01

    Should the laws of the world dealing with cross-border transactions be unified? Such unification presupposes an agreement on what we understand by ‘law’ and what its sources are. The drafters of uniform laws and lawyers who are preoccupied with comparative law often ask themselves: Is there, among...... the nations, a common core of legal values? If there is, this will facilitate legal unification. It will also make the international law-making easier if, in exceptional cases, a court is permitted to disregard a legal rule....

  5. Dark Matter in SuperGUT Unification Models

    International Nuclear Information System (INIS)

    Olive, Keith A

    2011-01-01

    After a brief update on the prospects for dark matter in the constrained version of the MSSM (CMSSM) and its differences with models based on minimal supergravity (mSUGRA), I will consider the effects of unifying the supersymmetry-breaking parameters at a scale above M GUT . One of the consequences of superGUT unification, is the ability to take vanishing scalar masses at the unification scale with a neutralino LSP dark matter candidate. This allows one to resurrect no-scale supergravity as a viable phenomenological model.

  6. F-theory uplifts and GUTs

    International Nuclear Information System (INIS)

    Blumenhagen, Ralph; Jurke, Benjamin; Grimm, Thomas W.; Weigand, Timo

    2009-01-01

    We study the F-theory uplift of Type IIB orientifold models on compact Calabi-Yau threefolds containing divisors which are del Pezzo surfaces. We consider two examples defined via del Pezzo transitions of the quintic. The first model has an orientifold projection leading to two disjoint O7-planes and the second involution acts via an exchange of two del Pezzo surfaces. The two uplifted fourfolds are generically singular with minimal gauge enhancements over a divisor and, respectively, a curve in the non-Fano base. We study possible further degenerations of the elliptic fiber leading to F-theory GUT models based on subgroups of E 8 .

  7. Gauge unification of basic forces, particularly of gravitation with strong interactions

    International Nuclear Information System (INIS)

    Salam, A.

    1977-01-01

    An attempt is made to present a case for the use of both the Einstein--Weyl spin-two and the Yang--Mills spin-one gauge structures for describing strong interactions. By emphasizing both spin-one and -two aspects of this force, it is hoped that a unification of this force, on the one hand, with gravity theory and, on the other, with the electromagnetic and weak interactions can be achieved. A Puppi type of tetrahedral interralation of fundamental forces, with the strong force playing a pivotal role due to its mediation through both spin-one and -two quanta, is proposed. It is claimed that the gauge invariance of gravity theory permits the use of ambuguity-free nonpolynomial techniques and thereby the securing of relistic regularization in gravity-modified field theories with the Newtonian constant G/sub N/ providing a relistic cutoff. 37 references

  8. Small numbers in supersymmetric theories of nature

    International Nuclear Information System (INIS)

    Graesser, Michael L.

    1999-01-01

    The Standard Model of particle interactions is a successful theory for describing the interactions of quarks, leptons and gauge bosons at microscopic distance scales. Despite these successes, the theory contains many unsatisfactory features. The origin of particle masses is a central mystery that has eluded experimental elucidation. In the Standard Model the known particles obtain their mass from the condensate of the so-called Higgs particle. Quantum corrections to the Higgs mass require an unnatural fine tuning in the Higgs mass of one part in 10 -32 to obtain the correct mass scale of electroweak physics. In addition, the origin of the vast hierarchy between the mass scales of the electroweak and quantum gravity physics is not explained in the current theory. Supersymmetric extensions to the Standard Model are not plagued by this fine tuning issue and may therefore be relevant in Nature. In the minimal supersymmetric Standard Model there is also a natural explanation for electroweak symmetry breaking. Supersymmetric Grand Unified Theories also correctly predict a parameter of the Standard Model. This provides non-trivial indirect evidence for these theories. The most general supersymmetric extension to the Standard Model however, is excluded by many physical processes, such as rare flavor changing processes, and the non-observation of the instability of the proton. These processes provide important information about the possible structure such a theory. In particular, certain parameters in this theory must be rather small. A physics explanation for why this is the case would be desirable. It is striking that the gauge couplings of the Standard Model unify if there is supersymmetry close to the weak scale. This suggests that at high energies Nature is described by a supersymmetric Grand Unified Theory. But the mass scale of unification must be introduced into the theory since it does not coincide with the probable mass scale of strong quantum gravity. The subject

  9. An Ordering Linear Unification Algorithm

    Institute of Scientific and Technical Information of China (English)

    胡运发

    1989-01-01

    In this paper,we present an ordering linear unification algorithm(OLU).A new idea on substituteion of the binding terms is introduced to the algorithm,which is able to overcome some drawbacks of other algorithms,e.g.,MM algorithm[1],RG1 and RG2 algorithms[2],Particularly,if we use the directed eyclie graphs,the algoritm needs not check the binding order,then the OLU algorithm can also be aplied to the infinite tree data struceture,and a higher efficiency can be expected.The paper focuses upon the discussion of OLU algorithm and a partial order structure with respect to the unification algorithm.This algorithm has been implemented in the GKD-PROLOG/VAX 780 interpreting system.Experimental results have shown that the algorithm is very simple and efficient.

  10. Geodesic congruences in the Palatini f(R) theory

    International Nuclear Information System (INIS)

    Shojai, Fatimah; Shojai, Ali

    2008-01-01

    We shall investigate the properties of a congruence of geodesics in the framework of Palatini f(R) theories. We shall evaluate the modified geodesic deviation equation and the Raychaudhuri's equation and show that f(R) Palatini theories do not necessarily lead to attractive forces. Also, we shall study energy condition for f(R) Palatini gravity via a perturbative analysis of the Raychaudhuri's equation.

  11. Gauge Coupling Unification with Partly Composite Matter

    International Nuclear Information System (INIS)

    Gherghetta, Tony

    2005-01-01

    It is shown how gauge coupling unification can occur in models with partly composite matter. The particle states which are composite only contribute small logarithmns to the running of gauge couplings, while the elementary states contribute the usual large logarithmns. This introduces a new differential running contribution to the gauge couplings from partly composite SU(5) matter multiplets. In particular, for partly supersymmetric models, the incomplete SU(5) elementary matter multiplets restore gauge coupling unification even though the usual elementary gaugino and Higgsino contributions need not be present

  12. Anomaly cancelation in field theory and F-theory on a circle

    International Nuclear Information System (INIS)

    Grimm, Thomas W.; Kapfer, Andreas

    2016-01-01

    We study the manifestation of local gauge anomalies of four- and six-dimensional field theories in the lower-dimensional Kaluza-Klein theory obtained after circle compactification. We identify a convenient set of transformations acting on the whole tower of massless and massive states and investigate their action on the low-energy effective theories in the Coulomb branch. The maps employ higher-dimensional large gauge transformations and precisely yield the anomaly cancelation conditions when acting on the one-loop induced Chern-Simons terms in the three- and five-dimensional effective theory. The arising symmetries are argued to play a key role in the study of the M-theory to F-theory limit on Calabi-Yau manifolds. For example, using the fact that all fully resolved F-theory geometries inducing multiple Abelian gauge groups or non-Abelian groups admit a certain set of symmetries, we are able to generally show the cancelation of pure Abelian or pure non-Abelian anomalies in these models.

  13. Physics of F-theory compactifications without section

    International Nuclear Information System (INIS)

    Anderson, Lara B.; García-Etxebarria, Iñaki; Grimm, Thomas W.; Keitel, Jan

    2014-01-01

    We study the physics of F-theory compactifications on genus-one fibrations without section by using an M-theory dual description. The five-dimensional action obtained by considering M-theory on a Calabi-Yau threefold is compared with a six-dimensional F-theory effective action reduced on an additional circle. We propose that the six-dimensional effective action of these setups admits geometrically massive U(1) vectors with a charged hypermultiplet spectrum. The absence of a section induces NS-NS and R-R three-form fluxes in F-theory that are non-trivially supported along the circle and induce a shift-gauging of certain axions with respect to the Kaluza-Klein vector. In the five-dimensional effective theory the Kaluza-Klein vector and the massive U(1)s combine into a linear combination that is massless. This U(1) is identified with the massless U(1) corresponding to the multi-section of the Calabi-Yau threefold in M-theory. We confirm this interpretation by computing the one-loop Chern-Simons terms for the massless vectors of the five-dimensional setup by integrating out all massive states. A closed formula is found that accounts for the hypermultiplets charged under the massive U(1)s.

  14. Geometric symmetries and topological terms in F-theory and field theory

    Energy Technology Data Exchange (ETDEWEB)

    Kapfer, Andreas

    2016-08-25

    In this thesis we investigate topological aspects and arithmetic structures in quantum field theory and string theory. Particular focus is put on consistent truncations of supergravity and compactifications of F-theory. The first part treats settings of supersymmetry breaking in five dimensions. We focus on an N=4 to N=2 breaking in gauged supergravity. For certain classes of embedding tensors we can analyze the theory around the vacuum to a great extent. Importantly, one-loop corrections to Chern-Simons terms are generically induced which are independent of the supersymmetry-breaking scale. We investigate concrete examples of consistent truncations of supergravity and M-theory which show this N=4 to N=2 breaking pattern in five dimensions. In particular, we analyze necessary conditions for these consistent truncations to be used as effective theories for phenomenology by demanding consistency of the scale-independent corrections to Chern-Simons couplings. The second part is devoted to the study of anomalies and large gauge transformations in circle-reduced gauge theories and F-theory. We consider four- and six-dimensional matter-coupled gauge theories on the circle and classify all large gauge transformations that preserve the boundary conditions of the matter fields. Enforcing that they act consistently on one-loop Chern-Simons couplings in three and five dimensions explicitly yields all higher-dimensional gauge anomaly cancelation conditions. In the context of F-theory compactifications we identify the classified large gauge transformations along the circle with arithmetic structures on elliptically fibered Calabi-Yau manifolds via the dual M-theory setting. Integer Abelian large gauge transformations correspond to free basis shifts in the Mordell-Weil lattice of rational sections while special fractional non-Abelian large gauge transformations are matched to torsional shifts in the Mordell-Weil group. For integer non-Abelian large gauge transformations we

  15. Gauge-Higgs unification with broken flavour symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Olschewsky, M.

    2007-05-15

    We study a five-dimensional Gauge-Higgs unification model on the orbifold S{sup 1}/Z{sub 2} based on the extended standard model (SM) gauge group SU(2){sub L} x U(1){sub Y} x SO(3){sub F}. The group SO(3){sub F} is treated as a chiral gauged flavour symmetry. Electroweak-, flavour- and Higgs interactions are unified in one single gauge group SU(7). The unified gauge group SU(7) is broken down to SU(2){sub L} x U(1){sub Y} x SO(3){sub F} by orbifolding and imposing Dirichlet and Neumann boundary conditions. The compactification scale of the theory is O(1) TeV. Furthermore, the orbifold S{sup 1}/Z{sub 2} is put on a lattice. This setting gives a well-defined staring point for renormalisation group (RG) transformations. As a result of the RG-flow, the bulk is integrated out and the extra dimension will consist of only two points: the orbifold fixed points. The model obtained this way is called an effective bilayered transverse lattice model. Parallel transporters (PT) in the extra dimension become nonunitary as a result of the blockspin transformations. In addition, a Higgs potential V({phi}) emerges naturally. The PTs can be written as a product e{sup A{sub y}}e{sup {eta}}e{sup A{sub y}} of unitary factors e{sup A{sub y}} and a selfadjoint factor e{sup {eta}}. The reduction 48 {yields} 35 + 6 + anti 6 + 1 of the adjoint representation of SU(7) with respect to SU(6) contains SU(2){sub L} x U(1){sub Y} x SO(3){sub F} leads to three SU(2){sub L} Higgs doublets: one for the first, one for the second and one for the third generation. Their zero modes serve as a substitute for the SM Higgs. When the extended SM gauge group SU(2){sub L} x U(1){sub Y} x SO(3){sub F} is spontaneously broken down to U(1){sub em}, an exponential gauge boson mass splitting occurs naturally. At a first step SU(2){sub L} x U(1){sub Y} x SO(3){sub F} is broken to SU(2){sub L} x U(1){sub Y} by VEVs for the selfadjoint factor e{sup {eta}}. This breaking leads to masses of flavour changing SO(3){sub F

  16. Problems in unification and supergravity

    International Nuclear Information System (INIS)

    Farrar, G.; Henyey, F.

    1984-01-01

    Problems in unification of the various gauge groups, quantum gravity, supersymmetry and supergravity, compact dimensions of space-time, and conditions at the beginning of the universe are discussed. Separate entries were prepared for the data base for the 15 papers presented

  17. Ten years after the unification : East Germany and the relevance of modern theories of trade, location and growth

    NARCIS (Netherlands)

    Brakman, S.; Schramm, M.; Garretsen, Harry

    2000-01-01

    In the paper we analyse, ten years after the German unification, the relevance of modern theoretical developments on trade, location and growth for East Germany using sectoral and regional data. Given our discussion of stylized facts about industry growth, economies of scale and differences in

  18. Dynamics of particles and fields. Final report

    International Nuclear Information System (INIS)

    Cahill, K.E.

    1985-01-01

    The principal objective of the proposed work is a better understanding of the internal and coordinate symmetries that characterize the interactions of the elementary particles. Their interactions - gravitational, weak, electromagnetic, and strong - seem to be well described by gauge theories, i.e., ones whose equations of motion are invariant under symmetry transformations that vary independently from point to point. The principal subject of the proposed research is the development of techniques for the numerical evaluation of path integrals, particularly those that occur in gauge theories. Other subjects of the proposed research are: quark confinement and other nonperturbative phenomena in field theory, gauge theories of compact and noncompact symmetry groups, supersymmetry, grand unification, the unification of the gravitational and electronuclear forces, and various topics in computer physics

  19. Discovery of proton decay: A must for theory, a challenge for experiment

    International Nuclear Information System (INIS)

    Pati, Jogesh C.

    2000-01-01

    It is noted that, but for one missing piece--proton decay--the evidence in support of grand unification is now strong. It includes: (i) the observed family-structure, (ii) the meeting of the gauge couplings, (iii) neutrino-oscillations, (iv) the intricate pattern of the masses and mixings of all fermions, including the neutrinos, and (v) the need for B-L as a generator, to implement baryogenesis. Taken together, these not only favor grand unification but in fact select out a particular route to such unification, based on the ideas of supersymmetry, SU(4)-color and left-right symmetry. Thus they point to the relevance of an effective string-unified G(224) or SO(10)-symmetry. A concrete proposal is presented, within a predictive SO(10)/G(224)-framework, that successfully describes the masses and mixings of all fermions, including the neutrinos--with eight predictions, all in agreement with observation. Within this framework, a systematic study of proton decay is carried out, which pays special attention to its dependence on the fermion masses, including the superheavy Majorana masses of the right-handed neutrinos. The study shows that a conservative upper limit on the proton lifetime is about (1/2-1)x10 34 yrs, with ν(bar sign)K + being the dominant decay mode, and as a distinctive feature, μ + K 0 being prominent. This in turn strongly suggests that an improvement in the current sensitivity by a factor of five to ten (compared to SuperK) ought to reveal proton decay. Otherwise some promising and remarkably successful ideas on unification would suffer a major setback

  20. A non Supersymmetric SO(10) Grand Unified Model for All the Physics below $M_{GUT}$

    CERN Document Server

    Altarelli, Guido

    2013-01-01

    We present a renormalizable non supersymmetric Grand Unified SO(10) model which, at the price of a large fine tuning, is compatible with all compelling phenomenological requirements below the unification scale and thus realizes a minimal extension of the SM, unified in SO(10) and describing all known physics below $M_{GUT}$. These requirements include coupling unification at a large enough scale to be compatible with the bounds on proton decay; a Yukawa sector in agreement with all the data on quark and lepton masses and mixings and with leptogenesis as the origin of the baryon asymmetry of the Universe; an axion arising from the Higgs sector of the model, suitable to solve the strong CP problem and to account for the observed amount of Dark Matter. The above constraints imposed by the data are very stringent and single out a particular breaking chain with the Pati-Salam group at an intermediate scale $M_I\\sim10^{11}$ GeV.

  1. R-parity violation in F-theory

    Energy Technology Data Exchange (ETDEWEB)

    Romão, Miguel Crispim [Physics and Astronomy, University of Southampton,SO17 1BJ Southampton (United Kingdom); Karozas, Athanasios [Physics Department, Theory Division, Ioannina University,GR-45110 Ioannina (Greece); King, Stephen F. [Physics and Astronomy, University of Southampton,SO17 1BJ Southampton (United Kingdom); Leontaris, George K. [Physics Department, Theory Division, Ioannina University,GR-45110 Ioannina (Greece); Meadowcroft, Andrew K. [Physics and Astronomy, University of Southampton,SO17 1BJ Southampton (United Kingdom)

    2016-11-14

    We discuss R-parity violation (RPV) in semi-local and local F-theory constructions. We first present a detailed analysis of all possible combinations of RPV operators arising from semi-local F-theory spectral cover constructions, assuming an SU(5) GUT. We provide a classification of all possible allowed combinations of RPV operators originating from operators of the form 10⋅5̄⋅5̄, including the effect of U(1) fluxes with global restrictions. We then relax the global constraints and perform explicit computations of the bottom/tau and RPV Yukawa couplings, at an SO(12) local point of enhancement in the presence of general fluxes subject only to local flux restrictions. We compare our results to the experimental limits on each allowed RPV operator, and show that operators such as LLe{sup c}, LQd{sup c} and u{sup c}d{sup c}d{sup c} may be present separately within current bounds, possibly on the edge of observability, suggesting lepton number violation or neutron-antineutron oscillations could constrain F-theory models.

  2. Automated Systematic Generation and Exploration of Flat Direction Phenomenology in Free Fermionic Heterotic String Theory

    Science.gov (United States)

    Greenwald, Jared

    Any good physical theory must resolve current experimental data as well as offer predictions for potential searches in the future. The Standard Model of particle physics, Grand Unied Theories, Minimal Supersymmetric Models and Supergravity are all attempts to provide such a framework. However, they all lack the ability to predict many of the parameters that each of the theories utilize. String theory may yield a solution to this naturalness (or self-predictiveness) problem as well as offer a unifed theory of gravity. Studies in particle physics phenomenology based on perturbative low energy analysis of various string theories can help determine the candidacy of such models. After a review of principles and problems leading up to our current understanding of the universe, we will discuss some of the best particle physics model building techniques that have been developed using string theory. This will culminate in the introduction of a novel approach to a computational, systematic analysis of the various physical phenomena that arise from these string models. We focus on the necessary assumptions, complexity and open questions that arise while making a fully-automated at direction analysis program.

  3. Problems in unification and supergravity

    Energy Technology Data Exchange (ETDEWEB)

    Farrar, G.; Henyey, F. (eds.)

    1984-01-01

    Problems in unification of the various gauge groups, quantum gravity, supersymmetry and supergravity, compact dimensions of space-time, and conditions at the beginning of the universe are discussed. Separate entries were prepared for the data base for the 15 papers presented. (WHK)

  4. Grand unification in the heterotic brane world

    International Nuclear Information System (INIS)

    Vaudrevange, Patrick Karl Simon

    2008-08-01

    String theory is known to be one of the most promising candidates for a uni ed description of all elementary particles and their interactions. Starting from the ten-dimensional heterotic string, we study its compactification on six-dimensional orbifolds. We clarify some important technical aspects of their construction and introduce new parameters, called generalized discrete torsion. We identify intrinsic new relations between orbifolds with and without (generalized) discrete torsion. Furthermore, we perform a systematic search for MSSM-like models in the context of Z 6 -II orbifolds. Using local GUTs, which naturally appear in the heterotic brane world, we construct about 200 MSSM candidates. We find that intermediate SUSY breaking through hidden sector gaugino condensation is preferred in this set of models. A specific model, the so-called benchmark model, is analyzed in detail addressing questions like the identification of a supersymmetric vacuum with a naturally small μ-term and proton decay. Furthermore, as vevs of twisted fields correspond to a resolution of orbifold singularities, we analyze the resolution of Z 3 singularities in the local and in the compact case. Finally, we exemplify this procedure with the resolution of a Z 3 MSSM candidate. (orig.)

  5. Grand unification in the heterotic brane world

    Energy Technology Data Exchange (ETDEWEB)

    Vaudrevange, Patrick Karl Simon

    2008-08-15

    String theory is known to be one of the most promising candidates for a uni ed description of all elementary particles and their interactions. Starting from the ten-dimensional heterotic string, we study its compactification on six-dimensional orbifolds. We clarify some important technical aspects of their construction and introduce new parameters, called generalized discrete torsion. We identify intrinsic new relations between orbifolds with and without (generalized) discrete torsion. Furthermore, we perform a systematic search for MSSM-like models in the context of Z{sub 6}-II orbifolds. Using local GUTs, which naturally appear in the heterotic brane world, we construct about 200 MSSM candidates. We find that intermediate SUSY breaking through hidden sector gaugino condensation is preferred in this set of models. A specific model, the so-called benchmark model, is analyzed in detail addressing questions like the identification of a supersymmetric vacuum with a naturally small {mu}-term and proton decay. Furthermore, as vevs of twisted fields correspond to a resolution of orbifold singularities, we analyze the resolution of Z{sub 3} singularities in the local and in the compact case. Finally, we exemplify this procedure with the resolution of a Z{sub 3} MSSM candidate. (orig.)

  6. The Economic Implications of Korean Unification

    National Research Council Canada - National Science Library

    Schmitz, Jonathan

    2002-01-01

    .... To lessen this burden, South Korea will need to initiate policy reforms that can ease the financial stress and repercussions of unification and create an integrated economic community with North Korea...

  7. Symmetries of string, M- and F-theories

    NARCIS (Netherlands)

    Bergshoeff, Eric; Proeyen, Antoine Van

    2001-01-01

    The d = 10 type II string theories, d = 11 M-theory and d = 12 F-theory have the same symmetry group. It can be viewed either as a subgroup of a conformal group OSp(1|64) or as a contraction of OSp(1|32). The theories are related by different identifications of their symmetry operators as generators

  8. Yukawa couplings in SO(10) heterotic M-theory vacua

    International Nuclear Information System (INIS)

    Faraggi, Alon E.; Garavuso, Richard S.

    2003-01-01

    We demonstrate the existence of a class of N=1 supersymmetric nonperturbative vacua of Horava-Witten M-theory compactified on a torus fibered Calabi-Yau 3-fold Z with first homotopy group π 1 (Z)=Z 2 , having the following properties: (1) SO(10) grand unification group, (2) net number of three generations of chiral fermions in the observable sector, and (3) potentially viable matter Yukawa couplings. These vacua correspond to semistable holomorphic vector bundles V Z over Z having structure group SU(4) C , and generically contain M5-branes in the bulk space. The nontrivial first homotopy group allows Wilson line breaking of the SO(10) symmetry. Additionally, we propose how the 11-dimensional Horava-Witten M-theory framework may be used to extend the perturbative calculation of the top quark Yukawa coupling in the realistic free-fermionic models to the nonperturbative regime. The basic argument being that the relevant coupling couples twisted-twisted-untwisted states and can be calculated at the level of the Z 2 xZ 2 orbifold without resorting to the full three generation models

  9. Higgs mass in the gauge-Higgs unification

    International Nuclear Information System (INIS)

    Haba, Naoyuki; Takenaga, Kazunori; Yamashita, Toshifumi

    2005-01-01

    The gauge-Higgs unification theory identifies the zero mode of the extra-dimensional component of the gauge field as the usual Higgs doublet. Since this degree of freedom is the Wilson line phase, the Higgs does not have the mass term nor quartic coupling at the tree level. Through quantum corrections, the Higgs can take a vacuum expectation value, and its mass is induced. The radiatively induced mass tends to be small, although it can be lifted to O(100) GeV by introducing the O(10) numbers of bulk fields. Perturbation theory becomes unreliable when a large number of bulk fields are introduced. We reanalyze the Higgs mass based on useful expansion formulae for the effective potential and find that even a small number of bulk field can have the suitable heavy Higgs mass. We show that a small (large) number of bulk fields are enough (needed) when the SUSY breaking mass is large (small). We also study the case of introducing the soft SUSY breaking scalar masses in addition to the Scherk-Schwarz SUSY breaking and obtain the heavy Higgs mass due to the effect of the scalar mass

  10. String theory, supersymmetry, unification, and all that

    International Nuclear Information System (INIS)

    Schwarz, J.H.; Seiberg, N.

    1999-01-01

    String theory and supersymmetry are theoretical ideas that go beyond the standard model of particle physics and show promise for unifying all forces. After a brief introduction to supersymmetry, the authors discuss the prospects for its experimental discovery in the near future. They then show how the magic of supersymmetry allows us to solve certain quantum field theories exactly, thus leading to new insights about field theory dynamics related to electric-magnetic duality. The discussion of superstring theory starts with its perturbation expansion, which exhibits new features including open-quotes stringy geometry.close quotes The authors then turn to more recent nonperturbative developments. Using new dualities, all known superstring theories are unified, and their strong-coupling behavior is clarified. A central ingredient is the existence of extended objects called branes. copyright 1999 The American Physical Society

  11. Stellar configurations in f(R) theories of gravity

    International Nuclear Information System (INIS)

    Henttunen, K.; Multamaeki, T.; Vilja, I.

    2008-01-01

    We study stellar configurations and the space-time around them in metric f(R) theories of gravity. In particular, we focus on the polytropic model of the Sun in two specific cases: the f(R)=R-μ 4 /R model and a model with a stabilizing higher order term f(R)=R-μ 4 /R+βR 3 /(3μ 4 ). We show how the stellar configuration in the f(R) theory can, by appropriate initial conditions, be selected to be equal to that described by the Lane-Emden equation and how a simple scaling relation exists between the solutions. We also derive the correct solution analytically near the center of the star in f(R) theory. Previous analytical and numerical results are confirmed, indicating that the space-time around the Sun is incompatible with solar system constraints in the f(R)=R-μ 4 /R model. Numerical work shows that stellar configurations, with a regular metric at the center, lead to γ PPN ≅1/2 outside the star for both models, i.e., the Schwarzschild-de Sitter space-time is not the correct vacuum solution for such configurations. This shows that even when one fine-tunes the initial conditions inside a star such that the mass of the effective scalar in the equivalent scalar-tensor theory is large, γ PPN is still 1/2 outside the star. Conversely, by selecting the Schwarzschild-de Sitter metric as the outside solution, or equivalently setting the mass of the effective scalar to be large outside the star, we find that the stellar configuration is unchanged but the metric is irregular at the center. The possibility of constructing a f(R) theory compatible with the solar system experiments and possible new constraints arising from the radius-mass relation of stellar objects is discussed

  12. Gravity-assisted exact unification in minimal supersymmetric SU(5) and its gaugino mass spectrum

    International Nuclear Information System (INIS)

    Tobe, Kazuhiro; Wells, James D.

    2004-01-01

    Minimal supersymmetric SU(5) with exact unification is naively inconsistent with proton decay constraints. However, it can be made viable by a gravity-induced non-renormalizable operator connecting the adjoint Higgs boson and adjoint vector boson representations. We compute the allowed coupling space for this theory and find natural compatibility with proton decay constraints even for relatively light superpartner masses. The modifications away from the naive SU(5) theory have an impact on the gaugino mass spectrum, which we calculate. A combination of precision linear collider and large hadron collider measurements of superpartner masses would enable interesting tests of the high-scale form of minimal supersymmetric SU(5)

  13. Unification of gauge couplings in radiative neutrino mass models

    DEFF Research Database (Denmark)

    Hagedorn, Claudia; Ohlsson, Tommy; Riad, Stella

    2016-01-01

    masses at one-loop level and (III) models with particles in the adjoint representation of SU(3). In class (I), gauge couplings unify in a few models and adding dark matter amplifies the chances for unification. In class (II), about a quarter of the models admits gauge coupling unification. In class (III......We investigate the possibility of gauge coupling unification in various radiative neutrino mass models, which generate neutrino masses at one- and/or two-loop level. Renormalization group running of gauge couplings is performed analytically and numerically at one- and two-loop order, respectively....... We study three representative classes of radiative neutrino mass models: (I) minimal ultraviolet completions of the dimension-7 ΔL = 2 operators which generate neutrino masses at one- and/or two-loop level without and with dark matter candidates, (II) models with dark matter which lead to neutrino...

  14. The Early Universe. Facts and fiction. 4. ed.

    International Nuclear Information System (INIS)

    Boerner, G.

    2003-01-01

    The following topics are covered in this completely new written textbook: The standard big bang model, thermodynamics of the Early universe, gauge theories and standard model, grand unification models, baryon synthesis, inflationary universe, dark matter and galaxy formation, evolution of small perturbations, non-linear structure formation (WL)

  15. The super G-string

    International Nuclear Information System (INIS)

    Gates, V.; Kangaroo, E.; Roachcock, M.; Gall, W.C.

    1986-01-01

    The authors describe a string theory which gives all the phenomenology of symmetry breaking. It makes use of higher dimensions, higher derivatives, higher spin, higher twist, and hierarchy. It discusses the problems of renormalizability of gravity, the cosmological constant, grand unification, supersymmetry breaking, and the command cold

  16. Gauge-Higgs unification with brane kinetic terms

    International Nuclear Information System (INIS)

    Aranda, Alfredo; Diaz-Cruz, J. Lorenzo

    2006-01-01

    By identifying the Higgs field as an internal component of a higher-dimensional gauge field it is possible to solve the little hierarchy problem. The construction of a realistic model that incorporates such a gauge-Higgs unification is an important problem that demands attention. In fact, several attempts in this direction have already been put forward. In this Letter we single out one such attempt, a 6D SU(3) extended electroweak theory, where it is possible to obtain a Higgs mass prediction in accord with global fits. One shortcoming of the model is its prediction for the Weinberg angle, it is too large. We slightly modify the model by including brane kinetic terms in a way motivated by the orbifold action on the 6D fields. We show that in this way it is possible to obtain the correct Weinberg angle while keeping the desired results in the Higgs sector

  17. Electroweak symmetry breaking in supersymmetric gauge-Higgs unification models

    International Nuclear Information System (INIS)

    Choi, Kiwoon; Jeong, Kwang-Sik; Okumura, Ken-ichi; Haba, Naoyuki; Shimizu, Yasuhiro; Yamaguchi, Masahiro

    2004-01-01

    We examine the Higgs mass parameters and electroweak symmetry breaking in supersymmetric orbifold field theories in which the 4-dimensional Higgs fields originate from higher-dimensional gauge supermultiplets. It is noted that such gauge-Higgs unification leads to a specific boundary condition on the Higgs mass parameters at the compactification scale, which is independent of the details of supersymmetry breaking mechanism. With this boundary condition, phenomenologically viable parameter space of the model is severely constrained by the condition of electroweak symmetry breaking for supersymmetry breaking scenarios which can be realized naturally in orbifold field theories. For instance, if it is assumed that the 4-dimensional effective theory is the minimal supersymmetric standard model with supersymmetry breaking parameters induced by the Scherk-Schwarz mechanism, a correct electroweak symmetry breaking can not be achieved for reasonable range of parameters of the model, even when one includes additional contributions to the Higgs mass parameters from the auxiliary component of 4-dimensional conformal compensator. However if there exists a supersymmetry breaking mediated by brane superfields, sizable portion of the parameter space can give a correct electroweak symmetry breaking. (author)

  18. Asymptotic freedom in the theory of the strong interaction. Comment on the nobel prize in physics 2004

    International Nuclear Information System (INIS)

    Zhang Zhaoxi

    2005-01-01

    The 2004 Nobel Prize in Physics was awarded to David J. Gross, Frank Wilczek and H. David Politzer for their decisive contributions to the theory of the asymptotic freedom of the strong interaction (a fundamental interaction). The fundamental elements of quantum chromodynamics (QCD) and the theory of the strong interaction are briefly reviewed in their historical context. How to achieve asymptotic freedom is introduced and its physical meaning explained. The latest experimental tests of asymptotic freedom are presented, and it is shown that the theoretical prediction agrees excellently with the experimental measurements. Perturbative QCD which is based on the asymptotic freedom is outlined. It is pointed out that the theoretical discovery and experimental proof of the asymptotic freedom are crucial for QCD to be the correct theory of strong interaction. Certain frontier research areas of QCD, such as 'color confinement', are mentioned. The discovery and confirmation of asymptotic freedom has indeed deeply affected particle physics, and has led to QCD becoming a main content of the standard model, and to further development of the so-called grand unification theories of interactions. (author)

  19. Progress on The GEMS (Gravity Electro-Magnetism-Strong) Theory of Field Unification and Its Application to Space Problems

    International Nuclear Information System (INIS)

    Brandenburg, J. E.

    2008-01-01

    Progress on the GEMS (Gravity Electro-Magnetism-Strong), theory is presented as well as its application to space problems. The GEMS theory is now validated through the Standard Model of physics. Derivation of the value of the Gravitation constant based on the observed variation of α with energy: results in the formula G congruent with (ℎ/2π)c/M ηc 2 exp(-1/(1.61α)), where α is the fine structure constant,(ℎ/2π), is Planck's constant, c, is the speed of light, and M ηc is the mass of the η cc Charmonium meson that is shown to be identical to that derived from the GEM postulates. Covariant formulation of the GEM theory is now possible through definition of the spacetime metric tensor as a portion of the EM stress tensor normalized by its own trace: g ab = 4(F c a F cb )/(F ab F ab ), it is found that this results in a massless ground state vacuum and a Newtonian gravitation potential φ = 1/2 E 2 /B 2 . It is also found that a Lorentz or flat-space metric is recovered in the limit of a full spectrum ZPF

  20. A Unified Grand Tour of Theoretical Physics

    CERN Document Server

    Lawrie, Ian D

    2002-01-01

    A unified account of the principles of theoretical physics, A Unified Grand Tour of Theoretical Physics, Second Edition stresses the inter-relationships between areas that are usually treated as independent. The profound unifying influence of geometrical ideas, the powerful formal similarities between statistical mechanics and quantum field theory, and the ubiquitous role of symmetries in determining the essential structure of physical theories are emphasized throughout.This second edition conducts a grand tour of the fundamental theories that shape our modern understanding of the physical wor

  1. Search for Z′, vacuum (instability and hints of high-energy structures

    Directory of Open Access Journals (Sweden)

    Accomando Elena

    2016-01-01

    Full Text Available We study the high-energy behaviour of a class of anomaly-free abelian extensions of the Standard Model. We focus on the interplay among the phenomenological characterisation of the model and the use of precise renormalisation group methods. Using as boundary conditions regions of the parameter space at the verge of current LHC probe, interesting unification patterns emerge linked to thresholds belonging to a SO(10 grand unification theory (GUT. We stress how the evolution of the mixing between the two abelian factors may provide a valuable tool to address the candidate high-energy embedding. The emerging unification scenarios are then challenged to be perturbative and to allow for a stable vacuum.

  2. The Unification of Private International Law

    Directory of Open Access Journals (Sweden)

    Emira Kazazi

    2015-07-01

    Full Text Available Civil and the common law approaching Europe is no longer a “future project”, but more and more rather a present attempt (Kötz, 2003 – 2004. In this prism, concentrating on the European International Private Law within the space of mixed jurisdictions, it may seem surprising in light of the attempts to create a new European ius commune. But is it possible that a unification of the material law may sign the start of the end of the European conflicts of laws? Last but not the least private international law is not just a choice of law. The unification of the private law, in its definition as a concept, does not influence two of the three pillars of the private international law: respectively, that of the jurisdiction and recognition as well as implementation of foreign decisions.

  3. The superquantum theory. Candidate for the theory of everything. 2. ed.; Die Superquantum Theorie. Kandidat fuer die ''Theory of Everything''

    Energy Technology Data Exchange (ETDEWEB)

    Bulut, Shevkinaz; Gorgels, Arno

    2008-05-15

    The following topics are dealt with: The search for the universal concept of the world formula, starting of the new physics era by the superquantum theory, number distance and potential field, set theory, the possible solution of the century problem of Cantor, gravitation, derivation of the imaginary unit j{sup 2}=-1, background noise, eigenspaces, unification of the natural forces. (HSI)

  4. On the vacuum of the minimal nonsupersymmetric SO(10) unification

    CERN Document Server

    Bertolini, Stefano; Malinsky, Michal

    2010-01-01

    We study a class of nonsupersymmetric SO(10) grand unified scenarios where the first stage of the symmetry breaking is driven by the vacuum expectation values of the 45-dimensional adjoint representation. Three decade old results claim that such a Higgs setting may lead exclusively to the flipped SU(5) x U(1) intermediate stage. We show that this conclusion is actually an artifact of the tree level potential. The study of the accidental global symmetries emerging in various limits of the scalar potential offers a simple understanding of the tree level result and a rationale for the drastic impact of quantum corrections. We scrutinize in detail the simplest and paradigmatic case of the 45_{H} + 16_{H} Higgs sector triggering the breaking of SO(10) to the standard electroweak model. We show that the minimization of the one-loop effective potential allows for intermediate SU(4)_C x SU(2)_L x U(1)_R and SU(3)_c x SU(2)_L x SU(2)_R x U(1)_{B-L} symmetric stages as well. These are the options favoured by gauge unif...

  5. Einstein's Legacy, at the Globe

    CERN Multimedia

    2005-01-01

    One-hundred years on, Albert Einstein's theories continue to fuel the daily work of physicists. From research into gravity waves to the quest for grand unification in physics, today's researchers have not finished with the legacy of the most famous and iconic physicist of the 20th Century.

  6. Neutrino mass textures from F-theory

    CERN Document Server

    Antoniadis, I

    2013-01-01

    Experimental data on the neutrino mixing and masses strongly suggest an underlying approximate symmetry of the relevant Yukawa superpotential terms. Intensive phenomenological explorations during the last decade indicate that permutation symmetries such as S_4, A_4 and their subgroups, under certain assumptions and vacuum alignments, predict neutrino mass textures compatible with such data. Motivated by these findings, in the present work we analyse the neutrino properties in F-theory GUT models derived in the framework of the maximal underlying E_8 symmetry in the elliptic fibration. More specifically, we consider local F-SU(5) GUT models and study in detail spectral cover geometries with monodromies associated to the finite symmetries S_4, A_4 and their transitive subgroups, including the dihedral group D_4 and Z_2 X Z_2. We discuss various issues that emerge in the implementation of S_4, A_4 neutrino models in the F-theory context and suggest how these can be resolved. Realistic models are presented for th...

  7. Post-sphaleron baryogenesis and n- anti n oscillation in non-SUSY SO(10) GUT with gauge coupling unification

    International Nuclear Information System (INIS)

    Patra, Sudhanwa; Pritimita, Prativa

    2014-01-01

    ''Post-sphaleron baryogenesis'', a fresh and profound mechanism of baryogenesis accounts for the matter-antimatter asymmetry of our present universe in a framework of Pati-Salam symmetry. We attempt here to embed this mechanism in a non-SUSY SO(10) grand unified theory by reviving a novel symmetry breaking chain with Pati-Salam symmetry as an intermediate symmetry breaking step and as well to address post-sphaleron baryogenesis and neutron-antineutron oscillation in a rational manner. The Pati-Salam symmetry based on the gauge group SU(2) L x SU(2) R x SU(4) C is realized in our model at 10 5 -10 6 GeV and the mixing time for the neutron-antineutron oscillation process having ΔB = 2 is found to be τ n- anti n ≅ 10 8 -10 10 s with the model parameters, which is within the reach of forthcoming experiments. Other novel features of the model include low scale right-handed W R ± , Z R gauge bosons, explanation for neutrino oscillation data via the gauged inverse (or extended) seesaw mechanism and most importantly TeV scale color sextet scalar particles responsible for an observable n- anti n oscillation which may be accessible to LHC. We also look after gauge coupling unification and an estimation of the proton lifetime with and without the addition of color sextet scalars. (orig.)

  8. New static solutions in f(T) theory

    Energy Technology Data Exchange (ETDEWEB)

    Daouda, M.H.; Rodrigues, Manuel E. [Universidade Federal do Espirito Santo, Centro de Ciencias Exatas, Departamento de Fisica, Vitoria, ES (Brazil); Houndjo, M.J.S. [Universidade Federal da Bahia, Instituto de Fisica, Salvador, BA (Brazil)

    2011-11-15

    We consider the equations of motion of an anisotropic space-time in f(T) theory, where T is the torsion. New spherically symmetric solutions of black holes and wormholes are obtained with a constant torsion and for the cases for which the radial pressure is proportional to a real constant, to some algebraic functions f(T) and their derivatives f{sub T}(T), or vanishes identically. (orig.)

  9. The gravitational sector of 2d (0,2) F-theory vacua

    International Nuclear Information System (INIS)

    Lawrie, Craig; Schäfer-Nameki, Sakura; Weigand, Timo

    2017-01-01

    F-theory compactifications on Calabi-Yau fivefolds give rise to two-dimensional N=(0,2) supersymmetric field theories coupled to gravity. We explore the dilaton supergravity defined by the moduli sector of such compactifications. The massless moduli spectrum is found by uplifting Type IIB compactifications on Calabi-Yau fourfolds. This spectrum matches expectations from duality with M-theory on the same elliptic fibration. The latter defines an N=2 Supersymmetric Quantum Mechanics related to the 2d (0,2) F-theory supergravity via circle reduction. Using our recent results on the gravitational anomalies of duality twisted D3-branes wrapping curves in Calabi-Yau fivefolds we show that the F-theory spectrum is anomaly free. We match the classical Chern-Simons terms of the M-theory Super Quantum Mechanics to one-loop contributions to the effective action by S 1 reduction of the dual F-theory.

  10. The gravitational sector of 2d (0,2) F-theory vacua

    Energy Technology Data Exchange (ETDEWEB)

    Lawrie, Craig [Institut für Theoretische Physik, Ruprecht-Karls-Universität,Philosophenweg 19, Heidelberg, 69120 (Germany); Schäfer-Nameki, Sakura [Mathematical Institute, University of Oxford,Woodstock Road, Oxford, OX2 6GG (United Kingdom); Weigand, Timo [Institut für Theoretische Physik, Ruprecht-Karls-Universität,Philosophenweg 19, Heidelberg, 69120 (Germany)

    2017-05-19

    F-theory compactifications on Calabi-Yau fivefolds give rise to two-dimensional N=(0,2) supersymmetric field theories coupled to gravity. We explore the dilaton supergravity defined by the moduli sector of such compactifications. The massless moduli spectrum is found by uplifting Type IIB compactifications on Calabi-Yau fourfolds. This spectrum matches expectations from duality with M-theory on the same elliptic fibration. The latter defines an N=2 Supersymmetric Quantum Mechanics related to the 2d (0,2) F-theory supergravity via circle reduction. Using our recent results on the gravitational anomalies of duality twisted D3-branes wrapping curves in Calabi-Yau fivefolds we show that the F-theory spectrum is anomaly free. We match the classical Chern-Simons terms of the M-theory Super Quantum Mechanics to one-loop contributions to the effective action by S{sup 1} reduction of the dual F-theory.

  11. Extension of loop quantum gravity to f(R) theories.

    Science.gov (United States)

    Zhang, Xiangdong; Ma, Yongge

    2011-04-29

    The four-dimensional metric f(R) theories of gravity are cast into connection-dynamical formalism with real su(2) connections as configuration variables. Through this formalism, the classical metric f(R) theories are quantized by extending the loop quantization scheme of general relativity. Our results imply that the nonperturbative quantization procedure of loop quantum gravity is valid not only for general relativity but also for a rather general class of four-dimensional metric theories of gravity.

  12. Constraints on four dimensional effective field theories from string and F-theory

    Energy Technology Data Exchange (ETDEWEB)

    Baume, Florent

    2017-06-21

    This thesis is a study of string theory compactifications to four dimensions and the constraints the Effective Field theories must exhibit, exploring both the closed and open sectors. In the former case, we focus on axion monodromy scenarios and the impact the backreaction of the energy density induced by the vev of an axion has on its field excursions. For all the cases studied, we find that the backreaction is small up to a critical value, and the proper field distance is flux independent and at most logarithmic in the axion vev. We then move to the open sector, where we use the framework of F-theory. We first explore the relation between the spectra arising from F-theory GUTs and those coming from a decomposition of the adjoint of E{sub 8} to SU(5) x U(1){sup n}. We find that extending the latter spectrum with new SU(5)-singlet fields, and classifying all possible ways of breaking the Abelian factors, all the spectra coming from smooth elliptic fibration constructed in the literature fit in our classification. We then explore generic properties of the spectra arising when breaking SU(5) to the Standard Model gauge group while retaining some anomaly properties. We finish by a study of F-theory compactications on a singular elliptic fibration via Matrix Factorisation, and find the charged spectrum of two non-Abelian examples.

  13. Constraints on four dimensional effective field theories from string and F-theory

    International Nuclear Information System (INIS)

    Baume, Florent

    2017-01-01

    This thesis is a study of string theory compactifications to four dimensions and the constraints the Effective Field theories must exhibit, exploring both the closed and open sectors. In the former case, we focus on axion monodromy scenarios and the impact the backreaction of the energy density induced by the vev of an axion has on its field excursions. For all the cases studied, we find that the backreaction is small up to a critical value, and the proper field distance is flux independent and at most logarithmic in the axion vev. We then move to the open sector, where we use the framework of F-theory. We first explore the relation between the spectra arising from F-theory GUTs and those coming from a decomposition of the adjoint of E 8 to SU(5) x U(1) n . We find that extending the latter spectrum with new SU(5)-singlet fields, and classifying all possible ways of breaking the Abelian factors, all the spectra coming from smooth elliptic fibration constructed in the literature fit in our classification. We then explore generic properties of the spectra arising when breaking SU(5) to the Standard Model gauge group while retaining some anomaly properties. We finish by a study of F-theory compactications on a singular elliptic fibration via Matrix Factorisation, and find the charged spectrum of two non-Abelian examples.

  14. Gauge hierarchy in an SO(10) supersymmetric grand unified model

    International Nuclear Information System (INIS)

    Zhiyong, Z.

    1982-01-01

    An SO(10) supersymmetric grand unified model is constructed in which the gauge hierarchy problem may be solved. Using Higgs superfields belonging to the SO(10) representations 16, 10 and 54, it is found that if SO(10) is broken down to SU(3)sub(c)xSU(2)sub(L)xU(1) via SO(6)xSO(4)approximately equal to SU(4)sub(c)xSU(2)sub(L)xSU(2)sub(R) at unification mass scales without supersymmetry breaking, the gauge hierarchy puzzle might be carried away. It is also shown that the colour-triplet Higgs, which mediates proton decay, is superheavy by an incredibly accurate, but 'natural' adjustment of parameters in the potential. (author)

  15. The superquantum theory. Candidate for the theory of everything. 2. ed.

    International Nuclear Information System (INIS)

    Bulut, Shevkinaz; Gorgels, Arno

    2008-05-01

    The following topics are dealt with: The search for the universal concept of the world formula, starting of the new physics era by the superquantum theory, number distance and potential field, set theory, the possible solution of the century problem of Cantor, gravitation, derivation of the imaginary unit j 2 =-1, background noise, eigenspaces, unification of the natural forces. (HSI)

  16. Linear theory of equatorial spread F

    International Nuclear Information System (INIS)

    Hudson, M.K.; Kennel, C.F.

    1975-01-01

    A fluid dispersion relation for the drift and interchange (Rayleigh-Taylor) modes in a collisional plasma forms the basis for a linear theory of equatorial spread F. The collisional drift mode growth rate will exceed the growth rate of the Rayleigh-Taylor mode at short perpendicular wavelengths and density gradient scale lengths, and the drift mode can grow on top side as well as on bottom side density gradients. However, below the F peak, where spread F predominates, it is concluded that both the drift and the Rayleigh-Taylor modes contribute to the total spread F spectrum, the Rayleigh-Taylor mode dominating at long and the drift mode at short perpendicular wavelengths above the ion Larmor radius

  17. Grand Prix Eurovision: Eine Fankultur im Medienzeitalter

    Directory of Open Access Journals (Sweden)

    Heinz Moser

    2017-06-01

    Full Text Available Der Grand Prix Eurovision ist seit Jahrzehnten eine der bekanntesten Unterhaltungssendungen im europäischen Raum. Dennoch erregte es Verwunderung, wenn der Schreibende Bekannten darüber berichtete, daß dies ein Forschungsgegenstand sei. Wurde von Interviews mit Grand Prix-Fans erzählt, so fielen schnell Aussagen wie: „Wie kann man sich nur für so etwas Abseitiges und Triviales wie den Grand Prix interessieren“. Dennoch bin ich der Meinung, daß Fankulturen für die entstehende Mediengesellschaft ein nicht unwichtiges Forschungsthema darstellen. Zwar geht es nicht um eine medienpädagogische Fragestellung im engeren Sinne; die Fans des Grand Prix Eurovision sind dem Jugendalter längst entwachsen. Dennoch handelt es sich bei Fangemeinschaften um Phänomene, die im Rahmen von Jugend- und Kinderkulturen von besonderer Relevanz sind. So meint Winter (1997, daß jugendliche Fanwelten eine bedeutende Rolle als Kristallisationspunkte kultureller Differenzierung spielen: ,Die Zugehörigkeit zu einer Fan weit ist Teil der jugendlichen Lebensbewältigung in der Postmoderne, denn in der Gemeinschaft der Fans können Jugendliche emotionale Allianzen eingehen, außeralltäglichen Beschäftigungen nachgehen, expressive Identitätsmuster gemeinschaftlich realisieren und sich mit ihrer Lebenssituation als Heranwachsende auseinandersetzen“ (Winter 1997, S. 51f..

  18. Beyond the Standard Model

    CERN Multimedia

    CERN. Geneva

    2005-01-01

    The necessity for new physics beyond the Standard Model will be motivated. Theoretical problems will be exposed and possible solutions will be described. The goal is to present the exciting new physics ideas that will be tested in the near future. Supersymmetry, grand unification, extra dimensions and string theory will be presented.

  19. Similarity-Based Unification: A Multi-Adjoint Approach

    Czech Academy of Sciences Publication Activity Database

    Medina, J.; Ojeda-Aciego, M.; Vojtáš, Peter

    2004-01-01

    Roč. 146, č. 1 (2004), s. 43-62 ISSN 0165-0114 Source of funding: V - iné verejné zdroje Keywords : similarity * fuzzy unification Subject RIV: BA - General Mathematics Impact factor: 0.734, year: 2004

  20. Grandes nouvelles dimensions et gravité quantique au coin

    Science.gov (United States)

    Arkani-Hamed, Nima; Dimopoulos, Savas; Dvali, Gia

    2003-04-01

    The electroweak unification mass may be the only fundamental scale in nature. If so, the visible universe may lie on a membrane floating within a higher dimensional space; new dimensions, black holes, quantum gravity, and string theory may become experimentally accessible in this decade. The dark matter could reside on parallel universes inside the extra dimensions. To cite this article: N. Arkani-Hamed et al., C. R. Physique 4 (2003).

  1. Dynamic Theory: a new view of space, time, and matter

    International Nuclear Information System (INIS)

    Williams, P.E.

    1980-12-01

    The theory presented represents a different approach toward unification of the various branches of physics. The foundation of the theory rests upon generalizations of the classical laws of thermodynamics, particularly Caratheodory's abstract statement of the second law. These adopted laws are shown to produce, as special cases, current theories such as Einstein's General and Special Relativity, Maxwell's electromagnetism, classical thermodynamics, and quantum principles. In addition to this unification, the theory provides predictions that may be experimentally investigated. Some of the predictions are a limiting rate of mass conversion, reduced pressures in electromagnetically contained plasmas, increased viscous effects in shocked materials, a finite self-energy for a charged particle, and the possible creation of particles with velocities greater than the speed of light. 8 figures

  2. Prepotential, Mirror Map and F-Theory on K3

    CERN Document Server

    Lerche, W.

    1998-01-01

    We compute certain one-loop corrections to F^4 couplings of the heterotic string compactified on T^2, and show that they can be characterized by holomorphic prepotentials. We then discuss how some of these couplings can be obtained in F-theory, or more precisely from 7-brane geometry in type IIB language. We in particular study theories with E_8 x E_8 and SO(8)^4 gauge symmetry, on certain one-dimensional sub-spaces of the moduli space that correspond to constant IIB coupling. For these theories, the relevant geometry can be mapped to Riemann surfaces. Physically, the computations amount to non-trivial tests of the basic F-theory -- heterotic duality in eight dimensions. Mathematically, they mean to associate holomorphic 5-point couplings of the form (del_t)^5 G = sum[ g_l l^5 q^l/(1-q^l) ] to K3 surfaces. This can be seen as a novel manifestation of the mirror map, acting here between open and closed string sectors.

  3. The geometry and physics of Abelian gauge groups in F-theory

    Energy Technology Data Exchange (ETDEWEB)

    Keitel, Jan

    2015-07-14

    In this thesis we study the geometry and the low-energy effective physics associated with Abelian gauge groups in F-theory compactifications. To construct suitable torus-fibered Calabi-Yau manifolds, we employ the framework of toric geometry. By identifying appropriate building blocks of Calabi-Yau manifolds that can be studied independently, we devise a method to engineer large numbers of manifolds that give rise to a specified gauge group and achieve a partial classification of toric gauge groups. Extending our analysis from gauge groups to matter spectra, we prove that the matter content of the most commonly studied F-theory set-ups is rather constrained. To circumvent such limitations, we introduce an algorithm to analyze torus-fibrations defined as complete intersections and present several novel kinds of F-theory compactifications. Finally, we show how torus-fibrations without section are linked to fibrations with multiple sections through a network of successive geometric transitions. In order to investigate the low-energy effective physics resulting from our compactifications, we apply M- to F-theory duality. After determining the effective action of F-theory with Abelian gauge groups in six dimensions, we compare the loop-corrected Chern-Simons terms to topological quantities of the compactification manifold to read off the massless matter content. Under certain assumptions, we show that all gravitational and mixed anomalies are automatically canceled in F-theory. Furthermore, we compute the low-energy effective action of F-theory compactifications without section and suggest that the absence of a section signals the presence of an additional massive Abelian gauge field. Adjusting our analysis to four dimensions, we show that remnants of this massive gauge field survive as discrete symmetries that impose selection rules on the Yukawa couplings of the effective theory.

  4. The geometry and physics of Abelian gauge groups in F-theory

    International Nuclear Information System (INIS)

    Keitel, Jan

    2015-01-01

    In this thesis we study the geometry and the low-energy effective physics associated with Abelian gauge groups in F-theory compactifications. To construct suitable torus-fibered Calabi-Yau manifolds, we employ the framework of toric geometry. By identifying appropriate building blocks of Calabi-Yau manifolds that can be studied independently, we devise a method to engineer large numbers of manifolds that give rise to a specified gauge group and achieve a partial classification of toric gauge groups. Extending our analysis from gauge groups to matter spectra, we prove that the matter content of the most commonly studied F-theory set-ups is rather constrained. To circumvent such limitations, we introduce an algorithm to analyze torus-fibrations defined as complete intersections and present several novel kinds of F-theory compactifications. Finally, we show how torus-fibrations without section are linked to fibrations with multiple sections through a network of successive geometric transitions. In order to investigate the low-energy effective physics resulting from our compactifications, we apply M- to F-theory duality. After determining the effective action of F-theory with Abelian gauge groups in six dimensions, we compare the loop-corrected Chern-Simons terms to topological quantities of the compactification manifold to read off the massless matter content. Under certain assumptions, we show that all gravitational and mixed anomalies are automatically canceled in F-theory. Furthermore, we compute the low-energy effective action of F-theory compactifications without section and suggest that the absence of a section signals the presence of an additional massive Abelian gauge field. Adjusting our analysis to four dimensions, we show that remnants of this massive gauge field survive as discrete symmetries that impose selection rules on the Yukawa couplings of the effective theory.

  5. MEG studies prohibited muon decays to explore grand unified theories of elementary particles

    International Nuclear Information System (INIS)

    Mori, Toshinori

    2009-01-01

    The MEG experiment, designed and proposed by Japanese physicists, is being carried out at Paul Scherrer Institute (PSI) in Switzerland, in collaboration with physicists from Italy, Switzerland, Russia and U.S.A. The experiment will make an extensive search for a muon's two-body decay into an electron and a gamma ray, μ→eγ, which is prohibited in the Standard Model of elementary particles, to explore Supersymmetric Grand Unified Theories. This article gives a brief description of the MEG experiment with an emphasis on the innovative experimental techniques developed to achieve the unprecedented experimental sensitivity. (author)

  6. Perturbation constraint on particle masses in the Weinberg-Salam model with two massless Higgs doublets

    International Nuclear Information System (INIS)

    Inoue, Kenzo; Nakano, Yoshimasa; Kakuto, Akira.

    1980-01-01

    The Weinberg-Salam model with two Higgs doublets is investigated. The spontaneous breakdown of the gauge symmetry is assumed to be produced by the Coleman-Weinberg mechanism, keeping gauge hierarchies in grand unified theories in mind. A discrete symmetry is introduced to secure flavor-diagonal Yukawa interactions of neutral Higgs bosons and the absence of the axion. Bounds on various masses are obtained by imposing coupling constants to lie in a finite range for the validity of the perturbation theory. It will be found that there must be at least one Higgs boson whose mass is lighter than 40 GeV, in order to satisfy the perturbation constraint at the unification mass scale in grand unified theories. (author)

  7. Non-accelerator particle physics

    International Nuclear Information System (INIS)

    Steinberg, R.I.; Lane, C.E.

    1991-08-01

    The goals of this research were the experimental testing of fundamental theories of physics such as grand unification and the exploration of cosmic phenomena through the techniques of particle physics. We have worked on the MACRO experiment, which is employing a large area underground detector to search for grand unification magnetic monopoles and dark matter candidates and to study cosmic ray muons as well as low and high energy neutrinos; the νIMB project, which seeks to refurbish and upgrade the IMB water Cerenkov detector to perform an improved proton decay search together with a long baseline reactor neutrino oscillation experiments using a one kiloton liquid scintillator (the Perry experiment); and development of technology for improved liquid scintillators and for very low background materials in support of the MACRO and Perry experiments and for new solar neutrino experiments

  8. Non-accelerator particle physics

    International Nuclear Information System (INIS)

    Steinberg, R.I.; Lane, C.E.

    1991-09-01

    The goals of this research are the experimental testing of fundamental theories of physics such as grand unification and the exploration of cosmic phenomena through the techniques of particle physics. We are working on the MACRO experiment, which employs a large area underground detector to search for grand unification magnetic monopoles and dark matter candidates and to study cosmic ray muons as well as low and high energy neutrinos: the νIMB project, which seeks to refurbish and upgrade the IMB water Cerenkov detector to perform an improved proton decay search together with a long baseline reactor neutrino oscillation experiment using a kiloton liquid scintillator (the Perry experiment); and development of technology for improved liquid scintillators and for very low background materials in support of the MACRO and Perry experiments and for new solar neutrino experiments. 21 refs., 19 figs., 6 tabs

  9. From the numerics of dynamics to the dynamics of numerics and visa versa in high energy particle physics

    International Nuclear Information System (INIS)

    Zhong Ting

    2009-01-01

    Starting from the concepts of statistical symmetry we consider different aspects of the connections between nonlinear dynamics and high energy physics. We pay special attention to the interplay between number theory and dynamics. We subsequently utilize the so obtained insight to compute vital constants relevant to the program of grand unification and quantum gravity.

  10. On discrete symmetries and torsion homology in F-theory

    Energy Technology Data Exchange (ETDEWEB)

    Mayrhofer, Christoph [Arnold-Sommerfeld-Center, Ludwig-Maximilians-Universität München,München (Germany); Palti, Eran; Till, Oskar; Weigand, Timo [Institut für Theoretische Physik, Ruprecht-Karls-Universität Heidelberg,Heidelberg (Germany)

    2015-06-04

    We study the relation between discrete gauge symmetries in F-theory compactifications and torsion homology on the associated Calabi-Yau manifold. Focusing on the simplest example of a ℤ{sub 2} symmetry, we show that there are two physically distinct ways that such a discrete gauge symmetry can arise. First, compactifications of M-Theory on Calabi-Yau threefolds which support a genus-one fibration with a bi-section are known to be dual to six-dimensional F-theory vacua with a ℤ{sub 2} gauge symmetry. We show that the resulting five-dimensional theories do not have a ℤ{sub 2} symmetry but that the latter emerges only in the F-theory decompactification limit. Accordingly the genus-one fibred Calabi-Yau manifolds do not exhibit torsion in homology. Associated to the bi-section fibration is a Jacobian fibration which does support a section. Compactifying on these related but distinct varieties does lead to a ℤ{sub 2} symmetry in five dimensions and, accordingly, we find explicitly an associated torsion cycle. We identify the expected particle and membrane system of the discrete symmetry in terms of wrapped M2 and M5 branes and present a field-theory description of the physics for both cases in terms of circle reductions of six-dimensional theories. Our results and methods generalise straightforwardly to larger discrete symmetries and to four-dimensional compactifications.

  11. F-theory and the landscape of intersecting D7-branes

    Energy Technology Data Exchange (ETDEWEB)

    Braun, Andreas

    2010-02-05

    In this work, the moduli of D7-branes in type IIB orientifold compactifications and their stabilization by fluxes is studied from the perspective of F-theory. In F-theory, the moduli of the D7-branes and the moduli of the orientifold are unified in the moduli space of an elliptic Calabi-Yau manifold. This makes it possible to study flux the stabilization of D7-branes in an elegant manner. To answer phenomenological questions, one has to translate the deformations of the elliptic Calabi-Yau manifold of F-theory back to the positions and the shape of the D7-branes. We address this problem by constructing the homology cycles that are relevant for the deformations of the elliptic Calabi-Yau manifold.We show the viability of our approach for the case of elliptic two- and three-folds. Furthermore, we discuss a consistency conditions related to the intersections between D7-branes and orientifold planes which is automatically fulfilled in F-theory. Finally, we use our results to study the flux stabilization of D7-branes on the orientifold K3 x T{sup 2}/Z{sub 2} using F-theory on K3 x K3. In this context, we derive conditions on the fluxes to stabilize a given configuration of D7-branes. (orig.)

  12. F-theory and the landscape of intersecting D7-branes

    International Nuclear Information System (INIS)

    Braun, Andreas

    2010-01-01

    In this work, the moduli of D7-branes in type IIB orientifold compactifications and their stabilization by fluxes is studied from the perspective of F-theory. In F-theory, the moduli of the D7-branes and the moduli of the orientifold are unified in the moduli space of an elliptic Calabi-Yau manifold. This makes it possible to study flux the stabilization of D7-branes in an elegant manner. To answer phenomenological questions, one has to translate the deformations of the elliptic Calabi-Yau manifold of F-theory back to the positions and the shape of the D7-branes. We address this problem by constructing the homology cycles that are relevant for the deformations of the elliptic Calabi-Yau manifold.We show the viability of our approach for the case of elliptic two- and three-folds. Furthermore, we discuss a consistency conditions related to the intersections between D7-branes and orientifold planes which is automatically fulfilled in F-theory. Finally, we use our results to study the flux stabilization of D7-branes on the orientifold K3 x T 2 /Z 2 using F-theory on K3 x K3. In this context, we derive conditions on the fluxes to stabilize a given configuration of D7-branes. (orig.)

  13. Unification, small and large

    Energy Technology Data Exchange (ETDEWEB)

    Fritzsch, Harald

    1993-04-15

    Full text: Fruitful exchanges between particle physics, astrophysics and cosmology have become a common feature in the last decade. In January, Coral Gables near Miami was the stage for a 'Unified Symmetry in the Small and the Large' meeting. Coral Gables is a famous physics venue. In January 1964, the year that the quark model of hadrons emerged, Behram Kursunoglu initiated a series of particle physics meetings that continued for 20 years and formed a regular focus for this development. The final such meeting was in 1983, coinciding with both the 80th birthday of field theory pioneer Paul Dirac, who worked in Florida towards the end of his career, and the discovery of the W bosons at CERN. The resurrected Coral Gables meeting began with historical accounts of the emergence of Big Bang cosmology, by Robert Ralph and Herman Alpher, while Andrei Linde proposed our expanding universe as a small part of a stationary system, infinite both in space and in time. The observational status of Big Bang cosmology was reviewed by Bruce Partridge, John Mather and Martin Harwit, emphasizing the cosmic background radiation, where temperature is now measured by the COBE satellite detectors to 2.726 ± 0.01 OK. The tiny fluctuations observed by COBE pose problems for standard cold dark matter models. Edward ('Rocky') Kolb reported on new studies on the electroweak phase transition, based on an analogy with the physics of liquid crystals. Richard Holman discussed the fate of global symmetries at energies near the Planck (grand unification) energy, and Paul Steinhardt talked about tensorial and scalar metric fluctuations in the light of the COBE results. Anthony Tyson gave an impressive description of dark matter studies using gravitational lensing, now emerging as a unique tool for indirectly observing intervening dark matter. A neutrino mass of 10 electronvolts could account for observed dark matter distributions, but fails to provide the necessary seeds for galaxy formation. A

  14. Unification, small and large

    International Nuclear Information System (INIS)

    Fritzsch, Harald

    1993-01-01

    Full text: Fruitful exchanges between particle physics, astrophysics and cosmology have become a common feature in the last decade. In January, Coral Gables near Miami was the stage for a 'Unified Symmetry in the Small and the Large' meeting. Coral Gables is a famous physics venue. In January 1964, the year that the quark model of hadrons emerged, Behram Kursunoglu initiated a series of particle physics meetings that continued for 20 years and formed a regular focus for this development. The final such meeting was in 1983, coinciding with both the 80th birthday of field theory pioneer Paul Dirac, who worked in Florida towards the end of his career, and the discovery of the W bosons at CERN. The resurrected Coral Gables meeting began with historical accounts of the emergence of Big Bang cosmology, by Robert Ralph and Herman Alpher, while Andrei Linde proposed our expanding universe as a small part of a stationary system, infinite both in space and in time. The observational status of Big Bang cosmology was reviewed by Bruce Partridge, John Mather and Martin Harwit, emphasizing the cosmic background radiation, where temperature is now measured by the COBE satellite detectors to 2.726 ± 0.01 OK. The tiny fluctuations observed by COBE pose problems for standard cold dark matter models. Edward ('Rocky') Kolb reported on new studies on the electroweak phase transition, based on an analogy with the physics of liquid crystals. Richard Holman discussed the fate of global symmetries at energies near the Planck (grand unification) energy, and Paul Steinhardt talked about tensorial and scalar metric fluctuations in the light of the COBE results. Anthony Tyson gave an impressive description of dark matter studies using gravitational lensing, now emerging as a unique tool for indirectly observing intervening dark matter. A neutrino mass of 10 electronvolts could account for observed dark matter distributions, but fails to provide the necessary seeds for

  15. Unification and fermion mass structure

    International Nuclear Information System (INIS)

    Ross, Graham G.; Serna, Mario

    2008-01-01

    Grand Unified Theories predict relationships between the GUT-scale quark and lepton masses. Using new data in the context of the MSSM, we update the values and uncertainties of the masses and mixing angles for the three generations at the GUT scale. We also update fits to hierarchical patterns in the GUT-scale Yukawa matrices. The new data shows not all the classic GUT-scale mass relationships remain in quantitative agreement at small to moderate tanβ. However, at large tanβ, these discrepancies can be eliminated by finite, tanβ-enhanced, radiative, threshold corrections if the gluino mass has the opposite sign to the wino mass

  16. Stable Asymptotically Free Extensions (SAFEs) of the Standard Model

    International Nuclear Information System (INIS)

    Holdom, Bob; Ren, Jing; Zhang, Chen

    2015-01-01

    We consider possible extensions of the standard model that are not only completely asymptotically free, but are such that the UV fixed point is completely UV attractive. All couplings flow towards a set of fixed ratios in the UV. Motivated by low scale unification, semi-simple gauge groups with elementary scalars in various representations are explored. The simplest model is a version of the Pati-Salam model. The Higgs boson is truly elementary but dynamical symmetry breaking from strong interactions may be needed at the unification scale. A hierarchy problem, much reduced from grand unified theories, is still in need of a solution.

  17. New F-theory lifts

    International Nuclear Information System (INIS)

    Collinucci, Andres

    2009-01-01

    In this note, a procedure is developed to explicitly construct non-trivial F-theory lifts of perturbative IIB orientifold models on Calabi-Yau complete intersections in toric varieties. This procedure works on Calabi-Yau orientifolds where the involution coordinate can have arbitrary projective weight, as opposed to the well-known hypersurface cases where it has half the weight of the equation defining the CY threefold. This opens up the possibility of lifting more general setups, such as models that have O3-planes.

  18. A review of recent results on spread F theory

    International Nuclear Information System (INIS)

    Ossakow, S.L.

    1979-01-01

    Ionospheric Spread F was discovered some four decades ago. Yet only in the past few years has significant progress been made in the theoretical explanation of such phenomena. In particular, considerable effort has been expended to explain equatorial Spread F and the attendant satellite signal propagation scintillation phenomena. The present review dwells mainly in this low latitude area. The various linear plasma instabilities thought to initiate equatorial Spread F are discussed. Recent theoretical and numerical simulation studies of the nonlinear evolution of the collisional Rayleigh-Taylor instability in equatorial Spread F are reviewed. Also, analytical studies of rising equatorial Spread F bubbles in the collisional and collisionless Rayleigh-Taylor regime are discussed, as well as the nohlinear saturation of instabilities in these two regimes. Current theories on very small scale (< approx 10 meters) size irregularities observed by radar backscatter during equatorial Spread F and their relation to the larger wavelength scintillation causing irregularities are discussed. Application of turbulence theory to equatorial Spread F phenomena is reviewed. Remaining problems to be dealt with at equatorial latitudes are summarized. (Auth.)

  19. Yukawa sector of minimal SO(10) unification

    Energy Technology Data Exchange (ETDEWEB)

    Babu, K.S. [Department of Physics, Oklahoma State University,Stillwater, OK, 74078 (United States); Bajc, Borut [Jožef Stefan Institute,Ljubljana, 1000 (Slovenia); Saad, Shaikh [Department of Physics, Oklahoma State University,Stillwater, OK, 74078 (United States)

    2017-02-28

    We show that in SO(10) models, a Yukawa sector consisting of a real 10{sub H}, a real 120{sub H} and a complex 126{sub H} of Higgs fields can provide a realistic fit to all fermion masses and mixings, including the neutrino sector. Although the group theory of SO(10) demands that the 10{sub H} and 120{sub H} be real, most constructions complexify these fields and impose symmetries exterior to SO(10) to achieve predictivity. The proposed new framework with real10{sub H} and real120{sub H} relies only on SO(10) gauge symmetry, and yet has a limited number of Yukawa parameters. Our analysis shows that while there are restrictions on the observables, a good fit to the entire fermion spectrum can be realized. Unification of gauge couplings is achieved with an intermediate scale Pati-Salam gauge symmetry. Proton decay branching ratios are calculable, with the leading decay modes being p→ν̄π{sup +} and p→e{sup +}π{sup 0}.

  20. Testing the AGN Unification Model in the Infrared

    International Nuclear Information System (INIS)

    Ramos Almeida, C; Levenson, N A; Radomski, J T; Alonso-Herrero, A; Asensio Ramos, A; Rodríguez Espinosa, J M; Pérez García, A M; Packham, C; Mason, R; Díaz-Santos, T

    2012-01-01

    We present near-to-mid-infrared spectral energy distributions (SEDs) for 21 Seyfert galaxies, using subarcsecond resolution imaging data. Our aim is to compare the properties Seyfert 1 (Sy1) and Seyfert 2 (Sy2) tori using clumpy torus models and a Bayesian approach to fit the infrared (IR) nuclear SEDs. These dusty tori have physical sizes smaller than 6 pc radius, as derived from our fits. Active galactic nuclei (AGN) unification schemes account for a variety of observational differences in terms of viewing geometry. However, we find evidence that strong unification may not hold, and that the immediate dusty surroundings of Sy1 and Sy2 nuclei are intrinsically different. The Type 2 tori studied here are broader, have more clumps, and these clumps have lower optical depths than those of Type 1 tori. The larger the covering factor of the torus, the smaller the probability of having direct view of the AGN, and vice-versa. In our sample, Sy2 tori have larger covering factors (C T = 0.95±0.02) and smaller escape probabilities than those of Sy1 (C T = 0.5±0.1). Thus, on the basis of the results presented here, the classification of a Seyfert galaxy may depend more on the intrinsic properties of the torus rather than on its mere inclination, in contradiction with the simplest unification model.

  1. Static solutions with spherical symmetry in f(T) theories

    International Nuclear Information System (INIS)

    Wang Tower

    2011-01-01

    The spherically symmetric static solutions are searched for in some f(T) models of gravity theory with a Maxwell term. To do this, we demonstrate that reconstructing the Lagrangian of f(T) theories is sensitive to the choice of frame, and then we introduce a particular frame based on the conformally Cartesian coordinates. In this particular frame, the existence conditions of various solutions are presented. Our results imply that only a limited class of f(T) models can be solved in this frame. For more general models, the search for spherically symmetric static solutions is still an open and challenging problem, hopefully solvable in other frames.

  2. SO(14) unification of 3+1 families

    International Nuclear Information System (INIS)

    Karadayi, H.R.

    1982-03-01

    It is shown that the unification of 3+1 families is possible within the framework of 64 dimensional spinor representation of SO(14). Special care is given for a description without the heavy excess fermions such as conjugate and mirror or completely exotic fermions of some family unification schemes. With the aid of an intrinsic ''L-R Asymmetry'' mechanism which we proposed recently, the conventional strong and electromagnetic interactions are obtained for all four families by concentrating only on the symmetry breaking SO(14) → SU(3)sub(c) x U(1)sub(e.m.). However, the conventional weak interactions of the first three families are obtained just as in the standard SU(2)sub(L) x U(1)sub(Y) model, while those of the prescribed fourth family show certain differences. This is what we mean by 3+1 family unification. All vector particles mediating strong, electromagnetic and weak interactions which are the subjects of present phenomenological tests are specified among the vector fields of SO(14) and their mass mechanisms leading to a consistent description of this low-energy phenomenology are studied with the aid of the Higgs multiplets 14, 364, 1716 and 2002 of SO(14). Moreover, the fermion mass mechanisms are considered with the aid of these scalar multiplets and the contributions from these scalars to the vector and fermion masses are explicitly calculated. All these calculations are carried out in the new mathematical technique for the Lie algebra representations which we introduced recently. (author)

  3. Introduction to physics beyond the Standard Model

    CERN Document Server

    Giudice, Gian Francesco

    1998-01-01

    These lectures will give an introductory review of the main ideas behind the attempts to extend the standard-model description of elementary particle interactions. After analysing the conceptual motivations that lead us to blieve in the existence of an underlying fundamental theory, wi will discuss the present status of various theoretical constructs : grand unification, supersymmetry and technicolour.

  4. Beyond the Standard Model course

    CERN Multimedia

    CERN. Geneva HR-RFA

    2006-01-01

    The necessity for new physics beyond the Standard Model will be motivated. Theoretical problems will be exposed and possible solutions will be described. The goal is to present the exciting new physics ideas that will be tested in the near future, at LHC and elsewhere. Supersymmetry, grand unification, extra dimensions and a glimpse of string theory will be presented.

  5. Where are we in particle physics

    International Nuclear Information System (INIS)

    Treiman, S.B.

    1981-01-01

    The author gives a brief description of the current status of high energy physics regarding quantum chromodynamics and the unified theory of weak and electromagnetic interactions. In this connection the mass generation of leptons and quarks by spontaneous symmetry breaking is considered. Finally an outlook is given to grand unification with special regards to the proton decay. (HSI).

  6. F-theory and unpaired tensors in 6D SCFTs and LSTs

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, David R. [Department of Mathematics, University of California Santa Barbara, CA (United States); Department of Physics, University of California Santa Barbara, CA (United States); Rudelius, Tom [Jefferson Physical Laboratory, Harvard University, Cambridge, MA (United States)

    2016-08-15

    We investigate global symmetries for 6D SCFTs and LSTs having a single ''unpaired'' tensor, that is, a tensor with no associated gauge symmetry. We verify that for every such theory built from F-theory whose tensor has Dirac self-pairing equal to -1, the global symmetry algebra is a subalgebra of e{sub 8}. This result is new if the F-theory presentation of the theory involves a one-parameter family of nodal or cuspidal rational curves (i.e., Kodaira types I{sub 1} or II) rather than elliptic curves (Kodaira type I{sub 0}). For such theories, this condition on the global symmetry algebra appears to fully capture the constraints on coupling these theories to others in the context of multi-tensor theories. We also study the analogous problem for theories whose tensor has Dirac self-pairing equal to -2 and find that the global symmetry algebra is a subalgebra of su(2). However, in this case there are additional constraints on F-theory constructions for coupling these theories to others. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. F-theory and unpaired tensors in 6D SCFTs and LSTs

    International Nuclear Information System (INIS)

    Morrison, David R.; Rudelius, Tom

    2016-01-01

    We investigate global symmetries for 6D SCFTs and LSTs having a single ''unpaired'' tensor, that is, a tensor with no associated gauge symmetry. We verify that for every such theory built from F-theory whose tensor has Dirac self-pairing equal to -1, the global symmetry algebra is a subalgebra of e 8 . This result is new if the F-theory presentation of the theory involves a one-parameter family of nodal or cuspidal rational curves (i.e., Kodaira types I 1 or II) rather than elliptic curves (Kodaira type I 0 ). For such theories, this condition on the global symmetry algebra appears to fully capture the constraints on coupling these theories to others in the context of multi-tensor theories. We also study the analogous problem for theories whose tensor has Dirac self-pairing equal to -2 and find that the global symmetry algebra is a subalgebra of su(2). However, in this case there are additional constraints on F-theory constructions for coupling these theories to others. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Distinguishing f(R) theories from general relativity by gravitational lensing effect

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hongguang [Beijing Normal University, Department of Physics, Beijing (China); Aix Marseille Universite et Universite de Toulon, Centre de Physique Theorique (UMR 7332), Marseille (France); Wang, Xin; Li, Haida; Ma, Yongge [Beijing Normal University, Department of Physics, Beijing (China)

    2017-11-15

    The post-Newtonian formulation of a general class of f(R) theories is set up in a third-order approximation. It turns out that the information of a specific form of f(R) gravity is encoded in the Yukawa potential, which is contained in the perturbative expansion of the metric components. Although the Yukawa potential is canceled in the second-order expression of the effective refraction index of light, detailed analysis shows that the difference of the lensing effect between the f(R) gravity and general relativity does appear at the third order when √(f''(0)/f{sup '}(0)) is larger than the distance d{sub 0} to the gravitational source. However, the difference between these two kinds of theories will disappear in the axially symmetric spacetime region. Therefore only in very rare case the f(R) theories are distinguishable from general relativity by gravitational lensing effect in a third-order post-Newtonian approximation. (orig.)

  9. Sfermion mass degeneracy, superconformal dynamics, and supersymmetric grand unified theories

    International Nuclear Information System (INIS)

    Kobayashi, Tatsuo; Noguchi, Tatsuya; Nakano, Hiroaki; Terao, Haruhiko

    2002-01-01

    We discuss issues in a scenario where hierarchical Yukawa couplings are generated through the strong dynamics of superconformal field theories (SCFTs). Independently of the mediation mechanism of supersymmetry breaking, the infrared convergence property of SCFTs can provide an interesting solution to the supersymmetric flavor problem; sfermion masses are suppressed around the decoupling scale of SCFTs and eventually become degenerate to some degree, thanks to family-independent radiative corrections governed by the gaugino masses of the minimal supersymmetric standard model (MSSM). We discuss under what conditions the degeneracy of the sfermion mass can be estimated in a simple manner. We also discuss the constraints from lepton flavor violations. We then explicitly study sfermion mass degeneracy within the framework of grand unified theories coupled to SCFTs. It is found that the degeneracy for right-handed sleptons becomes worse in the conventional SU(5) model than in the MSSM. On the other hand, in the flipped SU(5)xU(1) model, each right-handed lepton is still an SU(5) singlet, whereas the B-ino mass M 1 is determined by two independent gaugino masses of SU(5)xU(1). These two properties enable us to have an improved degeneracy for the right-handed sleptons. We also speculate on how further improvement can be obtained in the SCFT approach

  10. Origin of Abelian gauge symmetries in heterotic/F-theory duality

    International Nuclear Information System (INIS)

    Cvetič, Mirjam; Grassi, Antonella; Klevers, Denis; Poretschkin, Maximilian; Song, Peng

    2016-01-01

    We study aspects of heterotic/F-theory duality for compactifications with Abelian gauge symmetries. We consider F-theory on general Calabi-Yau manifolds with a rank one Mordell-Weil group of rational sections. By rigorously performing the stable degeneration limit in a class of toric models, we derive both the Calabi-Yau geometry as well as the spectral cover describing the vector bundle in the heterotic dual theory. We carefully investigate the spectral cover employing the group law on the elliptic curve in the heterotic theory. We find in explicit examples that there are three different classes of heterotic duals that have U(1) factors in their low energy effective theories: split spectral covers describing bundles with S(U(m)×U(1)) structure group, spectral covers containing torsional sections that seem to give rise to bundles with SU(m)×ℤ_k structure group and bundles with purely non-Abelian structure groups having a centralizer in E_8 containing a U(1) factor. In the former two cases, it is required that the elliptic fibration on the heterotic side has a non-trivial Mordell-Weil group. While the number of geometrically massless U(1)’s is determined entirely by geometry on the F-theory side, on the heterotic side the correct number of U(1)’s is found by taking into account a Stückelberg mechanism in the lower-dimensional effective theory. In geometry, this corresponds to the condition that sections in the two half K3 surfaces that arise in the stable degeneration limit of F-theory can be glued together globally.

  11. Theory of 1/f noise-a new approach

    International Nuclear Information System (INIS)

    Kroupa, V.F.

    2005-01-01

    In the present contribution we will discuss a new mathematical model for generation of the 1/f or flicker noise by introducing the sampling process and emphasizing the necessity for flow of a medium-current, energy, etc. The new theory will be confronted with 1/f noise generated in crystal resonators and oscillators

  12. Explanatory Unification by Proofs in School Mathematics

    Science.gov (United States)

    Komatsu, Kotaro; Fujita, Taro; Jones, Keith; Naoki, Sue

    2018-01-01

    Kitcher's idea of 'explanatory unification', while originally proposed in the philosophy of science, may also be relevant to mathematics education, as a way of enhancing student thinking and achieving classroom activity that is closer to authentic mathematical practice. There is, however, no mathematics education research treating explanatory…

  13. Non-perturbative selection rules in F-theory

    Energy Technology Data Exchange (ETDEWEB)

    Martucci, Luca [Dipartimento di Fisica e Astronomia ‘Galileo Galilei’, Università di Padova, and I.N.F.N. Sezione di Padova, via Marzolo 8, Padova, I-35131 (Italy); Weigand, Timo [Institut für Theoretische Physik, Ruprecht-Karls-Universität, Philosophenweg 19, Heidelberg, 69120 (Germany)

    2015-09-29

    We discuss the structure of charged matter couplings in 4-dimensional F-theory compactifications. Charged matter is known to arise from M2-branes wrapping fibral curves on an elliptic or genus-one fibration Y. If a set of fibral curves satisfies a homological relation in the fibre homology, a coupling involving the states can arise without exponential volume suppression due to a splitting and joining of the M2-branes. If the fibral curves only sum to zero in the integral homology of the full fibration, no such coupling is possible. In this case an M2-instanton wrapping a 3-chain bounded by the fibral matter curves can induce a D-term which is volume suppressed. We elucidate the consequences of this pattern for the appearance of massive U(1) symmetries in F-theory and analyse the structure of discrete selection rules in the coupling sector. The weakly coupled analogue of said M2-instantons is worked out to be given by D1-F1 instantons. The generation of an exponentially suppressed F-term requires the formation of half-BPS bound states of M2 and M5-instantons. This effect and its description in terms of fluxed M5-instantons is discussed in a companion paper.

  14. F-theory on all toric hypersurface fibrations and its Higgs branches

    Energy Technology Data Exchange (ETDEWEB)

    Klevers, Denis [Department of Physics and Astronomy, University of Pennsylvania,Philadelphia, PA 19104-6396 (United States); Theory Group, Physics Department, CERN,CH-1211, Geneva 23 (Switzerland); Peña, Damián Kaloni Mayorga; Oehlmann, Paul-Konstantin [Bethe Center for Theoretical Physics, Physikalisches Institut der Universität Bonn,Nussallee 12, 53115 Bonn (Germany); Piragua, Hernan [Department of Physics and Astronomy, University of Pennsylvania,Philadelphia, PA 19104-6396 (United States); Reuter, Jonas [Bethe Center for Theoretical Physics, Physikalisches Institut der Universität Bonn,Nussallee 12, 53115 Bonn (Germany)

    2015-01-27

    We consider F-theory compactifications on genus-one fibered Calabi-Yau manifolds with their fibers realized as hypersurfaces in the toric varieties associated to the 16 reflexive 2D polyhedra. We present a base-independent analysis of the codimension one, two and three singularities of these fibrations. We use these geometric results to determine the gauge groups, matter representations, 6D matter multiplicities and 4D Yukawa couplings of the corresponding effective theories. All these theories have a non-trivial gauge group and matter content. We explore the network of Higgsings relating these theories. Such Higgsings geometrically correspond to extremal transitions induced by blow-ups in the 2D toric varieties. We recover the 6D effective theories of all 16 toric hypersurface fibrations by repeatedly Higgsing the theories that exhibit Mordell-Weil torsion. We find that the three Calabi-Yau manifolds without section, whose fibers are given by the toric hypersurfaces in ℙ{sup 2}, ℙ{sup 1}×ℙ{sup 1} and the recently studied ℙ{sup 2}(1,1,2), yield F-theory realizations of SUGRA theories with discrete gauge groups ℤ{sub 3}, ℤ{sub 2} and ℤ{sub 4}. This opens up a whole new arena for model building with discrete global symmetries in F-theory. In these three manifolds, we also find codimension two I{sub 2}-fibers supporting matter charged only under these discrete gauge groups. Their 6D matter multiplicities are computed employing ideal techniques and the associated Jacobian fibrations. We also show that the Jacobian of the biquadric fibration has one rational section, yielding one U(1)-gauge field in F-theory. Furthermore, the elliptically fibered Calabi-Yau manifold based on dP{sub 1} has a U(1)-gauge field induced by a non-toric rational section. In this model, we find the first F-theory realization of matter with U(1)-charge q=3.

  15. COMPARATIVE RESEARCHE REGARDING METABOLIC PROFILE OF THE CALIFORNIAN, NEW ZEALAND WHITE, GRAND CHINCHILLA MEAT RABIT BREEDS AND THE F1 NZCH HYBRIDS

    Directory of Open Access Journals (Sweden)

    DANIELA-MARCELA TOBĂ (GOINA

    2008-10-01

    Full Text Available Precious biological characteristics of rabbits make their breeding a very profitable occupation. The rabbit meat, organoleptically same to the white meat, is rich in proteins, but low in fats. Biological researched done in direction to elucidate the biochemical systems that are the basis for organism physiological processes, have revealed that the level in which this process are develop directly influence the rabbits productivity capacity. 60 rabbit’s heads was used as biological material, distributed in: 15 Californian, 15 New Zeeland White, 15 Grand Chinchilla and 15 F1NZCH hybrids obtained from cross-breeding the New Zeeland White as maternal form and Grand Chinchilla as paternal form. Blood was sampled from the rabbit and was biochemical analyzed. The studied indices were: total protein, albumin, urea, uric acid, creatinine, total bilirubine, cholesterol, triglyceride and glucose. The experimental lot formed from F1 NZCH hybrids registered a concentration of 2.1 mg/dl uric acid, and in the other three lots the concentration was under 2 mg/dl. In all four lots, uric acid value was in normal limits. The determined creatinine registered very low values, under 1 mg/dl, at the low limit of reference values. At hybrids from New Zeeland White as maternal form and Grand Chinchilla as paternal form, in equal environmental conditions, the serum biochemical analysis haven’t registered significant differences compared to pure breeds individuals.

  16. Families in the nonperturbative unification scheme

    Energy Technology Data Exchange (ETDEWEB)

    Kapetanakis, D. (National Research Centre for the Physical Sciences Democritos, Athens (Greece)); Theisen, S. (European Organization for Nuclear Research, Geneva (Switzerland)); Zoupanos, G. (Ethnikon Metsovion Polytechneion, Athens (Greece). Dept. of Physics)

    1989-10-12

    Within the nonperturbative unification framework of Maiani, Parisi and Petronzio, we examine the influence of the number of fermion and Higgs families, when they are grouped in representations of horizontal family groups, on the low energy couplings of the standard model. In this way we find a number of new phenomenologically acceptable solutions for the standard model's low energy couplings. (orig.).

  17. Families in the nonperturbative unification scheme

    International Nuclear Information System (INIS)

    Kapetanakis, D.; Theisen, S.; Zoupanos, G.

    1989-01-01

    Within the nonperturbative unification framework of Maiani, Parisi and Petronzio, we examine the influence of the number of fermion and Higgs families, when they are grouped in representations of horizontal family groups, on the low energy couplings of the standard model. In this way we find a number of new phenomenologically acceptable solutions for the standard model's low energy couplings. (orig.)

  18. Fixing D7-brane positions by F-theory fluxes

    International Nuclear Information System (INIS)

    Braun, A.P.; Hebecker, A.; Luedeling, C.; Valandro, R.

    2009-01-01

    To do realistic model building in type IIB supergravity, it is important to understand how to fix D7-brane positions by the choice of fluxes. More generally, F-theory model building requires the understanding of how fluxes determine the singularity structure (and hence gauge group and matter content) of the compactification. We analyse this problem in the simple setting of M-theory on K3xK3. Given a certain flux which is consistent with the F-theory limit, we can explicitly derive the positions at which D7 branes or stacks of D7 branes are stabilised. The analysis is based on a parameterization of the moduli space of type IIB string theory on T 2 /Z 2 (including D7-brane positions) in terms of the periods of integral cycles of M-theory on K3. This allows us, in particular, to select a specific desired gauge group by the choice of flux numbers.

  19. Authenticity and Unification in Quechua Language Planning.

    Science.gov (United States)

    Hornberger, Nancy H.; King, Kendall

    1998-01-01

    Examines the potentially problematic tension between the goals of authenticity and unification in Quechua-language planning. One case study examines the orthographic debate that arose in Peru, and the second case study concerns two indigenous communities in Saraguro in the Southern Ecuadorian highlands where Spanish predominates but two Quichua…

  20. Mathematical gauge theory with applications to the standard model of particle physics

    CERN Document Server

    Hamilton, Mark J D

    2017-01-01

    The Standard Model is the foundation of modern particle and high energy physics. This book explains the mathematical background behind the Standard Model, translating ideas from physics into a mathematical language and vice versa. The first part of the book covers the mathematical theory of Lie groups and Lie algebras, fibre bundles, connections, curvature and spinors. The second part then gives a detailed exposition of how these concepts are applied in physics, concerning topics such as the Lagrangians of gauge and matter fields, spontaneous symmetry breaking, the Higgs boson and mass generation of gauge bosons and fermions. The book also contains a chapter on advanced and modern topics in particle physics, such as neutrino masses, CP violation and Grand Unification. This carefully written textbook is aimed at graduate students of mathematics and physics. It contains numerous examples and more than 150 exercises, making it suitable for self-study and use alongside lecture courses. Only a basic knowledge of d...

  1. Electric dipole moments as a test of supersymmetric unification

    CERN Document Server

    Dimopoulos, Savas K; Dimopoulos, S; Hall, L J

    1995-01-01

    In a class of supersymmetric grand unified theories, including those based on the gauge group SO(10), there are new contributions to the electric dipole moments of the neutron and electron, which arise as a heavy top quark effect. These contributions arise from CKM-like phases, not from phases of the supersymmetry breaking operators, and can be reliably computed in terms of the parameters of the weak scale supersymmetric theory. For the expected ranges of these parameters, the electric dipole moments of the neutron and the electron are predicted to be close to present experimental limits.

  2. Spherically Symmetric Geometries in f(T) and f(R) Gravitational Theories

    International Nuclear Information System (INIS)

    Nashed, Gamal G. L.

    2015-01-01

    Using the well know relation between Ricci scalar, R, and torsion scalar, T, that is, R=-T-2∇_αT"α, we show that, for any spherically symmetric spacetime whose (i) scalar torsion vanishing, that is, T=T_μ_ν"αS_α"μ"ν=0 or (ii) total derivative term, that is, ∇_αT"α with T"α is the contraction of the torsion, vanishing, or (iii) the combination of scalar torsion and total derivative term vanishing, could be solution for f(T) and f(R) gravitational theories.

  3. Nonperturbative type IIB model building in the F-theory framework

    Energy Technology Data Exchange (ETDEWEB)

    Jurke, Benjamin Helmut Friedrich

    2011-02-28

    This dissertation is concerned with the topic of non-perturbative string theory, which is generally considered to be the most promising approach to a consistent description of quantum gravity. The five known 10-dimensional perturbative string theories are all interconnected by numerous dualities, such that an underlying non-perturbative 11-dimensional theory, called M-theory, is postulated. Due to several technical obstacles, little is known about the fundamental objects in this theory. There exists an alternative non-perturbative description to type IIB string theory, namely F-theory. Here the SL(2;Z) self-duality of IIB theory is geometrized in the form of an elliptic fibration over the space-time. Moreover, higher-dimensional objects like 7-branes are included via singularities into the geometric picture. This formally elegant description, however, requires significant technical effort for the construction of suitable compactification geometries, as many different aspects necessarily have to be dealt with at the same time. On the other hand, the generation of essential GUT building blocks like certain Yukawa couplings or spinor representations is easier compared to perturbative string theory. The goal of this study is therefore to formulate a unified theory within the framework of F-theory, that satisfies basic phenomenological constraints. Within this thesis, at first E3-brane instantons in type IIB string theory - 4-dimensional objects that are entirely wrapped around the invisible dimensions of space-time - are matched with M5-branes in F-theory. Such objects are of great importance in the generation of critical Yukawa couplings or the stabilization of the free parameters of a theory. Certain properties of M5-branes then allow to derive a new criterion for E3-branes to contribute to the superpotential. In the aftermath of this analysis, several compactification geometries are constructed and checked for basic properties that are relevant for semi

  4. Nonperturbative type IIB model building in the F-theory framework

    International Nuclear Information System (INIS)

    Jurke, Benjamin Helmut Friedrich

    2011-01-01

    This dissertation is concerned with the topic of non-perturbative string theory, which is generally considered to be the most promising approach to a consistent description of quantum gravity. The five known 10-dimensional perturbative string theories are all interconnected by numerous dualities, such that an underlying non-perturbative 11-dimensional theory, called M-theory, is postulated. Due to several technical obstacles, little is known about the fundamental objects in this theory. There exists an alternative non-perturbative description to type IIB string theory, namely F-theory. Here the SL(2;Z) self-duality of IIB theory is geometrized in the form of an elliptic fibration over the space-time. Moreover, higher-dimensional objects like 7-branes are included via singularities into the geometric picture. This formally elegant description, however, requires significant technical effort for the construction of suitable compactification geometries, as many different aspects necessarily have to be dealt with at the same time. On the other hand, the generation of essential GUT building blocks like certain Yukawa couplings or spinor representations is easier compared to perturbative string theory. The goal of this study is therefore to formulate a unified theory within the framework of F-theory, that satisfies basic phenomenological constraints. Within this thesis, at first E3-brane instantons in type IIB string theory - 4-dimensional objects that are entirely wrapped around the invisible dimensions of space-time - are matched with M5-branes in F-theory. Such objects are of great importance in the generation of critical Yukawa couplings or the stabilization of the free parameters of a theory. Certain properties of M5-branes then allow to derive a new criterion for E3-branes to contribute to the superpotential. In the aftermath of this analysis, several compactification geometries are constructed and checked for basic properties that are relevant for semi

  5. Left-right symmetry in weak interactions: present status

    International Nuclear Information System (INIS)

    Senjanovic, G.

    1983-01-01

    The basic features of the left-right symmetric electroweak theory are reviewed. The experimental situation regarding the scale M/sub R/ of the breakdown of parity is summarized. I further discuss in detail the connection with weak and strong CP violation and especially, grand unification. Also covered are the issues of cosmological domain walls and the compositeness of quarks and leptons. 57 references

  6. Gauge backgrounds and zero-mode counting in F-theory

    Science.gov (United States)

    Bies, Martin; Mayrhofer, Christoph; Weigand, Timo

    2017-11-01

    Computing the exact spectrum of charged massless matter is a crucial step towards understanding the effective field theory describing F-theory vacua in four dimensions. In this work we further develop a coherent framework to determine the charged massless matter in F-theory compactified on elliptic fourfolds, and demonstrate its application in a concrete example. The gauge background is represented, via duality with M-theory, by algebraic cycles modulo rational equivalence. Intersection theory within the Chow ring allows us to extract coherent sheaves on the base of the elliptic fibration whose cohomology groups encode the charged zero-mode spectrum. The dimensions of these cohomology groups are computed with the help of modern techniques from algebraic geometry, which we implement in the software gap. We exemplify this approach in models with an Abelian and non-Abelian gauge group and observe jumps in the exact massless spectrum as the complex structure moduli are varied. An extended mathematical appendix gives a self-contained introduction to the algebro-geometric concepts underlying our framework.

  7. Towards a new paradigm for quark-lepton unification

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Christopher [Laboratoire de Physique Subatomique et de Cosmologie, Université Grenoble-Alpes, CNRS/IN2P3,53 avenue des Martyrs, 38026 Grenoble Cedex (France)

    2017-05-03

    The quark and charged lepton mass patterns upset their naïve unification. In this paper, a new approach to solve this problem is proposed. Model-independently, we find that a successful unification can be achieved. A mechanism is identified by which the large top quark mass renders its third-generation leptonic partner very light. This state is thus identified with the electron. We then construct a toy model to implement dynamically this mechanism, using tree-level exchanges of vector leptons to relate the quark and charged lepton flavor structures. In a supersymmetric context, this same mechanism splits the squark masses, and third generation squarks end up much lighter than the others. Finally, the implementation of this mechanism in SU(5) GUT permits to avoid introducing any flavor structure beyond the two minimal Yukawa couplings, ensuring the absence of unknown mixing matrices and their potentially large impact on FCNC.

  8. Unification types of housing during Sochi Olympics

    Directory of Open Access Journals (Sweden)

    Aleksandr A. Babaev

    2011-05-01

    Full Text Available In the article the statement of the unification problem of housing accommodation of participants, spectators, staff, committee during the Winter Olympics in Sochi. We give a mathematical formalization of the problem, where the unknown variables are theelements of the combination of types of accommodation sorted by the level of comfortand representation.

  9. Supergravity theories

    International Nuclear Information System (INIS)

    Uehara, S.

    1985-01-01

    Of all supergravity theories, the maximal, i.e., N = 8 in 4-dimension or N = 1 in 11-dimension, theory should perform the unification since it owns the highest degree of symmetry. As to the N = 1 in d = 11 theory, it has been investigated how to compactify to the d = 4 theories. From the phenomenological point of view, local SUSY GUTs, i.e., N = 1 SUSY GUTs with soft breaking terms, have been studied from various angles. The structures of extended supergravity theories are less understood than those of N = 1 supergravity theories, and matter couplings in N = 2 extended supergravity theories are under investigation. The harmonic superspace was recently proposed which may be useful to investigate the quantum effects of extended supersymmetry and supergravity theories. As to the so-called Kaluza-Klein supergravity, there is another possibility. (Mori, K.)

  10. String cosmology. Large-field inflation in string theory

    International Nuclear Information System (INIS)

    Westphal, Alexander

    2014-09-01

    This is a short review of string cosmology. We wish to connect string-scale physics as closely as possible to observables accessible to current or near-future experiments. Our possible best hope to do so is a description of inflation in string theory. The energy scale of inflation can be as high as that of Grand Unification (GUT). If this is the case, this is the closest we can possibly get in energy scales to string-scale physics. Hence, GUT-scale inflation may be our best candidate phenomenon to preserve traces of string-scale dynamics. Our chance to look for such traces is the primordial gravitational wave, or tensor mode signal produced during inflation. For GUT-scale inflation this is strong enough to be potentially visible as a B-mode polarization of the cosmic microwave background (CMB). Moreover, a GUT-scale inflation model has a trans-Planckian excursion of the inflaton scalar field during the observable amount of inflation. Such large-field models of inflation have a clear need for symmetry protection against quantum corrections. This makes them ideal candidates for a description in a candidate fundamental theory like string theory. At the same time the need of large-field inflation models for UV completion makes them particularly susceptible to preserve imprints of their string-scale dynamics in the inflationary observables, the spectral index n s and the fractional tensor mode power r. Hence, we focus this review on axion monodromy inflation as a mechanism of large-field inflation in string theory.

  11. Testing GUTs: where do monopoles fit

    International Nuclear Information System (INIS)

    Ellis, J.

    1982-10-01

    The report shows why the inadequacies of the standard model of elementary particles impel some theorists toward embedding the strong, weak and electromagnetic interactions in a simple GUT group, and explains why the grand unification scale and hence the GUM (Grand Unified Monopoles) mass are expected to be so large (greater than or equal to 10 14 GeV). It goes on to describe some model GUTs, notably minimal SU(5) and supersymmetric (susy) GUTs. The grand unified analogues of generalized Cabibbo mixing angles are introduced relevant to the prediction of baryon decay modes in different theories as well as to the Decay modes catalyzed by GUMs. Phenomenologies of conventional and susy GUTs are contrasted including the potential increase in the grand unification scale as well as possible different baryon decay modes in susy GUTs. The phenomenology of GUMs is discussed, principally their ability to catalyze baryon decays. Some of the astrophysical and cosmological constraints on GUMs, GUMs, which make it difficult to imagine ever seeing a GUM and may impose serious restrictions on GUT model-building via their behavior in the very early universe are introduced. Finally, the reasons why GUMs are crucial aspects and tests of GUTs are summarized

  12. Conformal symmetry and the Higgs effect in the Einstein-Weinberg-Salam unified theory

    International Nuclear Information System (INIS)

    Pervushin, V.N.; Smirichinski, V.I.; Pawlowski, M.M.

    1997-11-01

    We consider the unification of the Einstein theory of gravity with a conformal invariant version of the standard model for electroweak interaction without the Higgs potential. In this theory, the evolution of the Universe and the elementary particle masses have one and the same cosmological origin. In the flat space limit, we get the σ-model version of the standard model. The cosmological consequences of such a unification are studied. The red shift formula and Hubble law are obtained under the conventional Friedmann assumption of homogeneous matter distribution. We show that the considered theory leads to a very small vacuum density of the Higgs field ρ Cosmic φ = 10 -34 ρ cr in contrast with the theory with the Higgs potential ρ Higgs φ =0 54 ρ cr . (author)

  13. Principles of the Unification of Our Agency

    Science.gov (United States)

    Roth, Klas

    2011-01-01

    Do we need principles of the unification of our agency, our mode of acting? Immanuel Kant and Christine Korsgaard argue that the reflective structure of our mind forces us to have some conception of ourselves, others and the world--including our agency--and that it is through will and reason, and in particular principles of our agency, that we…

  14. Summary talk

    International Nuclear Information System (INIS)

    Drell, S.D.

    1981-01-01

    To sum it all up: 1. QCD has made its mark and is here to stay with its J = 1 gluons. 2. A quantitative determination of the strong coupling constant α/sub s/, and scale parameter, Λ, remains for the future. The reliable processes from the theoretical point of view for determining their values will be R or the study of the 3-gluon decays of heavy onia still to be discovered. 3. Very deep questions such as the scale of grand unification and the hierarchy problem. viz. why is the weak interaction lifetime of the neutron so many orders of magnitude shorter than the proton decay lifetime, or why is the grand unification scale so much larger than the weak vector boson mass, remain beyond our understanding. 4. All theories, as so eloquently described in Professor Okun's beautiful talk, lead us to expect to observe evidence of scalars in the ee annihilation process, whether they arise from dynamical or spontaneous symmetry breaking

  15. N=2 extended supersymmetric GUTs

    International Nuclear Information System (INIS)

    Fayet, P.

    1984-01-01

    We construct N = 2 extended SUSY GUTs which provide a general association between massive spin-1 gauge bosons, spin-1/2 inos and spin-0 Higgs bosons. The corresponding gauge hypermultiplets are of four different types, while leptons and quarks are associated with mirror and spin-0 partners. The anticommutators of the two supersymmetry generators provide two spin-0 symmetry generators Zsub(s) and Zsub(p), which do not commute. Their field-independent parts and do commute, however, and appear as central charges in the symmetry algebra of the spontaneously broken gauge theory. These central charges and are linear combinations of global symmetry generators with grand unification generators such as the weak hypercharge (but not the electrical charge). They survive the electroweak symmetry breaking. They do not vanish for massive gauge hypermultiplets of types II and III, which verify M 2 = 2 + 2 > 0 and M 2 > 2 + 2 > 0, respectively. The formula M 2 approx.= 2 + 2 determines the mass spectrum on the grand unification scale, up to electroweak corrections. Finally, we indicate how our mass relations can be interpreted in a 5- or 6-dimensional formalism, the central charges appearing as the extra components of the covariant momentum along the compact fifth or sixth dimensions; and how to evaluate the grand unification mass msub(x) in terms of the lengths of the latter (msub(x)approx.=(h/2π)/Lsub(5(6))c). (orig./HSI)

  16. The weak interaction in nuclear, particle and astrophysics

    International Nuclear Information System (INIS)

    Grotz, K.; Klapdor, H.V.

    1989-01-01

    This book is an introduction to the concepts of weak interactions and their importance and consequences for nuclear physics, particle physics, neutrino physics, astrophysics and cosmology. After a general introduction to elementary particles and interactions the Fermi theory of weak interactions is described together with its connection with nuclear structure and beta decay including the double beta decay. Then, after a general description of gauge theories the Weinberg-Salam theory of the electroweak interactions is introduced. Thereafter the weak interactions are considered in the framework of grand unification. Then the physics of neutrinos is discussed. Thereafter connections of weak interactions with astrophysics are considered with special regards to the gravitational collapse and the synthesis of heavy elements in the r-process. Finally, the connections of grand unified theories and cosmology are considered. (HSI) With 141 figs., 39 tabs

  17. Unification of General Relativity with Quantum Field Theory

    International Nuclear Information System (INIS)

    Ni Jun

    2011-01-01

    In the frame of quantum field theory, instead of using the action principle, we deduce the Einstein equation from purely the general covariant principle and the homogeneity of spacetime. The Einstein equation is shown to be the gauge equation to guarantee the local symmetry of spacetime translation. Gravity is an apparent force due to the curvature of spacetime resulted from the conservation of energy-momentum. In the action of quantum field theory, only electroweak-strong interactions should be considered with the curved spacetime metric determined by the Einstein equation. (general)

  18. Moraceae da Ilha Grande, Angra dos Reis, Rio de Janeiro, Brasil. Moraceae of Ilha Grande, Angra dos Reis, Rio de Janeiro, Brazil.

    Directory of Open Access Journals (Sweden)

    Leandro Cardoso PEDERNEIRAS

    2012-06-01

    Full Text Available Este trabalho apresenta o levantamento florístico das espécies nativas de Moraceae ocorrentes na Ilha Grande, município de Angra dos Reis, Estado do Rio de Janeiro, Brasil. Com base na análise de coleções científicas, revisão da literatura e excursões a campo, foram registradas 11 espécies nativas: Brosimum guianense, Dorstenia arifolia, Ficus adhatodifolia, F. arpazusa, F. cyclophylla, F. gomelleira, F. nevesiae, F. organensis, F. pulchella, Sorocea hilarii, S. guilleminiana. Apresentamos, também, a chave de identificação para os táxons, descrições, ilustrações, informações sobre a distribuição geográfica e comentários sobre as espécies. This work presents a floristic survey of native species of Moraceae occurring in Ilha Grande, municipality of Angra dos Reis, Rio de Janeiro state, Brazil. It was based on analysis of herbarium collections, literature review and the field excursions, resulting in 11 native species: Brosimum guianense, Dorstenia arifolia, Ficus adhatodifolia, F. arpazusa, F. cyclophylla, F. gomelleira, F. nevesiae, F. organensis, F. pulchella, Sorocea hilarii, S. guilleminiana. We also present the identification key to the taxa, descriptions, illustrations, information about geographic distribution and comments on these species that enriched the results.

  19. Supersoft Symmetry Energy Encountering Non-Newtonian Gravity in Neutron Stars

    International Nuclear Information System (INIS)

    Wen Dehua; Li Baoan; Chen Liewen

    2009-01-01

    Considering the non-Newtonian gravity proposed in grand unification theories, we show that the stability and observed global properties of neutron stars cannot rule out the supersoft nuclear symmetry energies at suprasaturation densities. The degree of possible violation of the inverse-square law of gravity in neutron stars is estimated using an equation of state of neutron-rich nuclear matter consistent with the available terrestrial laboratory data.

  20. Unification of Forces: The Road to Jointness?

    Science.gov (United States)

    1991-05-15

    tend to resist large change--or innovation. Because organizations value "predictability, stability, and certainty," incremental change is the...preferred mode of behavior for organizations.29 Unification of the forces would be a large, rather than an incremental , change; thus, the services would...coordinating planning and bidgeting , providing unified direction, accounting and controlling weapons and equipment acquisition, eliminating duplication of

  1. Gauge fluxes in F-theory compactifications

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Ling

    2016-07-13

    In this thesis, we study the geometry and physics of gauge fluxes in F-theory compactifications to four dimensions. Motivated by the phenomenological requirement of chiral matter in realistic model building scenarios, we develop methods for a systematic analysis of primary vertical G{sub 4}-fluxes on torus-fibred Calabi-Yau fourfolds. In particular, we extend the well-known description of fluxes on elliptic fibrations with sections to the more general set-up of genus-one fibrations with multi-sections. The latter are known to give rise to discrete abelian symmetries in F-theory. We test our proposal for constructing fluxes in such geometries on an explicit model with SU(5) x Z{sub 2} symmetry, which is connected to an ordinary elliptic fibration with SU(5) x U(1) symmetry by a conifold transition. With our methods we systematically verify anomaly cancellation and tadpole matching in both models. Along the way, we find a novel way of understanding anomaly cancellation in 4D F-theory in purely geometric terms. This observation is further strengthened by a similar analysis of an SU(3) x SU(2) x U(1){sup 2} model. The obvious connection of this particular model with the Standard Model is then investigated in a more phenomenologically motivated survey. There, we will first provide possible matchings of the geometric spectrum with the Standard Model states, which highlights the role of the additional U(1) factor as a selection rule. In a second step, we then utilise our novel methods on flux computations to set up a search algorithm for semi-realistic chiral spectra in our Standard- Model-like fibrations over specific base manifolds B. As a demonstration, we scan over three choices P{sup 3}, Bl{sub 1}P{sup 3} and Bl{sub 2}P{sup 3} for the base. As a result we find a consistent flux that gives the chiral Standard Model spectrum with a vector-like triplet exotic, which may be lifted by a Higgs mechanism.

  2. String unification and leptophobic Z` in flipped SU(5)

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, J.L. [Rice Univ., Houston, TX (United States). Bonner Nuclear Labs.

    1997-01-01

    We summarize recent developments in the prediction for {alpha}{sub s}(M{sub Z}), self-consistent string unification and the dynamical determination of mass scales, and leptophobic Z` gauge bosons in the context of stringy flipped SU(5). (orig.).

  3. F-theory vacua with $\\mathbb Z_3$ gauge symmetry

    CERN Document Server

    Cvetič, Mirjam; Klevers, Denis; Piragua, Hernan; Poretschkin, Maximilian

    2015-01-01

    Discrete gauge groups naturally arise in F-theory compactifications on genus-one fibered Calabi-Yau manifolds. Such geometries appear in families that are parameterized by the Tate-Shafarevich group of the genus-one fibration. While the F-theory compactification on any element of this family gives rise to the same physics, the corresponding M-theory compactifications on these geometries differ and are obtained by a fluxed circle reduction of the former. In this note, we focus on an element of order three in the Tate-Shafarevich group of the general cubic. We discuss how the different M-theory vacua and the associated discrete gauge groups can be obtained by Higgsing of a pair of five-dimensional U(1) symmetries. The Higgs fields arise from vanishing cycles in $I_2$-fibers that appear at certain codimension two loci in the base. We explicitly identify all three curves that give rise to the corresponding Higgs fields. In this analysis the investigation of different resolved phases of the underlying geometry pla...

  4. Constraints on GUT 7-brane topology in F-theory

    International Nuclear Information System (INIS)

    Hayashi, Hirotaka; Kawano, Teruhiko; Watari, Taizan

    2012-01-01

    We study the relation between phenomenological requirements and the topology of the surfaces that GUT 7-branes wrap in F-theory compactifications. In addition to the exotic matter free condition in the hypercharge flux scenario of SU(5) GUT breaking, we analyze a new condition that comes from a discrete symmetry aligning the contributions to low-energy Yukawa matrices from a number of codimension-three singularity points. We see that the exotic matter free condition excludes Hirzebruch surfaces (except F 0 ) as the GUT surface, correcting an existing proof in the literature. We further find that the discrete symmetry for the alignment of the Yukawa matrices excludes del Pezzo surfaces and a rational elliptic surface as the GUT surface. Therefore, some GUT 7-brane surfaces are good for some phenomenological requirements, but sometimes not for others, and this aspect should be kept in mind in geometry search in F-theory compactifications.

  5. Reduced modular symmetries of threshold corrections and gauge coupling unification

    Energy Technology Data Exchange (ETDEWEB)

    Bailin, David; Love, Alex [Department of Physics & Astronomy, University of Sussex,Brighton, BN1 9QH (United Kingdom)

    2015-04-01

    We revisit the question of gauge coupling unification at the string scale in orbifold compactifications of the heterotic string for the supersymmetric Standard Model. In the presence of discrete Wilson lines threshold corrections with modular symmetry that is a subgroup of the full modular group arise. We find that reduced modular symmetries not previously reported are possible. We conjecture that the effects of such threshold corrections can be simulated using sums of terms built from Dedekind eta functions to obtain the appropriate modular symmetry. For the cases of the ℤ{sub 8}-I orbifold and the ℤ{sub 3}×ℤ{sub 6} orbifold it is easily possible to obtain gauge coupling unification at the “observed” scale with Kähler moduli T of approximately one.

  6. Las cinco grandes dimensiones de la personalidad

    Directory of Open Access Journals (Sweden)

    Jan ter Laak

    1996-12-01

    Full Text Available Este artículo revisa las distintas posiciones teóricas sobre las cinco grandes dimensiones de la personalidad, mostrando las semejanzas y diferencias entre las posturas teóricas. Esta contribución presenta lo siguiente: (a la génesis del contenido y la estructura de las cinco dimensiones; (b la fortaleza de las cinco dimensiones; (e la relación de las cinco grandes dimensiones con otros constructos de personalidad; (d discute el valor predictivo de las puntuaciones del perfil de las cinco dimensiones para criterios pertinentes; (e analiza el estatus teórico de las cinco dimensiones; (f discute críticas históricas sobre las cinco grandes dimensiones y se formulan respuestas a estas críticas; (g hace conjeturas para el futuro de las cinco grandes dimensiones; y (h concluye con algunas conclusiones y comentarios.

  7. Gauge theories

    International Nuclear Information System (INIS)

    Kenyon, I.R.

    1986-01-01

    Modern theories of the interactions between fundamental particles are all gauge theories. In the case of gravitation, application of this principle to space-time leads to Einstein's theory of general relativity. All the other interactions involve the application of the gauge principle to internal spaces. Electromagnetism serves to introduce the idea of a gauge field, in this case the electromagnetic field. The next example, the strong force, shows unique features at long and short range which have their origin in the self-coupling of the gauge fields. Finally the unification of the description of the superficially dissimilar electromagnetic and weak nuclear forces completes the picture of successes of the gauge principle. (author)

  8. The Story of the Universe

    CERN Multimedia

    CMS Outreach

    2003-01-01

    These pages were extracted from the 2003 CMS Experiment Brochure. These pages explain the story of our universe and how it was formed over time. All explanations are coupled with simple colorful illustrations, one per sheet. Each can be used as an individual teaching aid or together as a set. Topics covered: - Quantum Gravity Era- Grand Unification Era - Electro Weak Era - Protons and Neutrons Formation- Nuclei formation- Atoms and Light Era - Galaxy Formation - Today Humans wondering where this all came from- The Size of Things - Instruments and the observables- Particles (Leptons & Quarks) -Forces - Interactions: coupling of forces to matter - Short history and new frontiers - Unification of forces - Summary (includes timeline of theories/discoveries)

  9. On the 'principle of the quantumness', the quantumness of Relativity, and the computational grand-unification

    International Nuclear Information System (INIS)

    D'Ariano, Giacomo Mauro

    2010-01-01

    I will argue that the proposal of establishing operational foundations of Quantum Theory should have top-priority, and that the Lucien Hardy's program on Quantum Gravity should be paralleled by an analogous program on Quantum Field Theory (QFT), which needs to be reformulated, notwithstanding its experimental success. In this paper, after reviewing recently suggested operational 'principles of the quantumness', I address the problem on whether Quantum Theory and Special Relativity are unrelated theories, or instead, if the one implies the other. I show how Special Relativity can be indeed derived from causality of Quantum Theory, within the computational paradigm 'the universe is a huge quantum computer', reformulating QFT as a Quantum-Computational Field Theory (QCFT). In QCFT Special Relativity emerges from the fabric of the computational network, which also naturally embeds gauge invariance. In this scheme even the quantization rule and the Planck constant can in principle be derived as emergent from the underlying causal tapestry of space-time. In this way Quantum Theory remains the only theory operating the huge computer of the universe.Is the computational paradigm only a speculative tautology (theory as simulation of reality), or does it have a scientific value? The answer will come from Occam's razor, depending on the mathematical simplicity of QCFT. Here I will just start scratching the surface of QCFT, analyzing simple field theories, including Dirac's. The number of problems and unmotivated recipes that plague QFT strongly motivates us to undertake the QCFT project, since QCFT makes all such problems manifest, and forces a re-foundation of QFT.

  10. Advantages of unity with SU(4)-color: Reflections through neutrino oscillations, baryogenesis and proton decay

    Science.gov (United States)

    Pati, Jogesh C.

    2017-03-01

    By way of paying tribute to Abdus Salam, I first recall the ideas of higher unification which the two of us introduced in 1972-73 to remove certain shortcomings in the status of particle physics prevailing then, and then present their current role in theory as well as experiments. These attempts initiated the idea of grand unification and provided the core symmetry-structure G(2, 2, 4) = SU(2)L × SU(2)R × SU(4)-color towards such a unification. Embodied with quark-lepton unification and left-right symmetry, the symmetry G(2, 2, 4) is uniquely chosen as being the minimal one that permits members of a family to belong to a single multiplet. The minimal extension of G(2, 2, 4) to a simple group is given by the attractive SO(10)-symmetry that was suggested a year later. The new concepts, and the many advantages introduced by this core symmetry (which are, of course, retained by SO(10) as well) are noted. These include explanations of the observed: (i) (rather weird) electroweak and color quantum numbers of the members of a family; (ii) quantization of electric charge; (iii) electron-proton charge-ratio being - 1; (iv) the co-existence of quarks and leptons; (v) likewise that of the three basic forces — the weak, electromagnetic and strong; (vi) the non-trivial cancelation of the triangle anomalies within each family; and opening the door for (vii) the appealing concept of parity being an exact symmetry of nature at the fundamental level. In addition, as a distinguishing feature, both because of SU(4)-color and independently because of SU(2)R as well, the symmetry G(2, 2, 4) introduced, to my knowledge, for the first time in the literature: (viii) a new kind of matter — the right-handed (RH) neutrino (νR) — as a compelling member of each family, and together with it; (ix) (B-L) as a local symmetry. The RH neutrions — contrary to prejudices held in the 1970’s against neutrinos being massive and thereby against the existence of νR’s as well — have in

  11. Exploring the Use of Enterprise Content Management Systems in Unification Types of Organizations

    Directory of Open Access Journals (Sweden)

    Arshad Noreen Izza

    2014-03-01

    Full Text Available The aim of this paper is to better understand how highly standardized and integrated businesses known as unification types of organizations use Enterprise Content Management Systems (ECMS to support their business processes. Multiple case study approach was used to study the ways two unification organizations use their ECMS in their daily work practices. Arising from these case studies are insights into the differing ways in which ECMS is used to support businesses. Based on the comparisons of the two cases, this study proposed that unification organizations may use ECMS in four ways, for: (1 collaboration, (2 information sharing that supports a standardized process structure, (3 building custom workflows that support integrated and standardized processes, and (4 providing links and access to information systems. These findings may guide organizations that are highly standardized and integrated in fashion, to achieve their intended ECMS-use, to understand reasons for ECMS failures and underutilization and to exploit technologies investments.

  12. Breaking E8 to SO(16) in M-theory and F-theory

    International Nuclear Information System (INIS)

    Aldabe, F.

    1998-01-01

    M-theory on an 11-dimensional manifold with a boundary must have E 8 gauge groups at each boundary in order to cancel anomalies. The type IA supergravity must have SO(16) gauge group at each boundary in order to be a consistent theory. The latter action can be obtained from the former one via dimensional reduction. Here we make use of the current algebra of the open membrane which couples to the former action to explain why the gauge group E 8 breaks down to SO(16) in going from M-theory to type IA supergravity. We also use the same current algebra to explain why F-theory has an E 8 x E 8 gauge group in its strong coupling limit while it has an SO(16) x SO(16) gauge group in its weak coupling limit. (orig.)

  13. Origin of Abelian Gauge Symmetries in Heterotic/F-theory Duality

    CERN Document Server

    Cvetic, Mirjam; Klevers, Denis; Poretschkin, Maximilian; Song, Peng

    2016-01-01

    We study aspects of heterotic/F-theory duality for compactifications with Abelian gauge symmetries. We consider F-theory on general Calabi-Yau manifolds with a rank one Mordell-Weil group of rational sections. By rigorously performing the stable degeneration limit in a class of toric models, we derive both the Calabi-Yau geometry as well as the spectral cover describing the vector bundle in the heterotic dual theory. We carefully investigate the spectral cover employing the group law on the elliptic curve in the heterotic theory. We find in explicit examples that there are three different classes of heterotic duals that have U(1) factors in their low energy effective theories: split spectral covers describing bundles with S(U(m) x U(1)) structure group, spectral covers containing torsional sections that seem to give rise to bundles with SU(m) x Z_k structure group and bundles with purely non-Abelian structure groups having a centralizer in E_8 containing a U(1) factor. In the former two cases, it is required ...

  14. Gauge unification, non-local breaking, open strings

    International Nuclear Information System (INIS)

    Trapletti, M.

    2005-01-01

    The issue of non-local GUT symmetry breaking is addressed in the context of open string model building. We study Z N xZ M ' orbifolds with all the GUT-breaking orbifold elements acting freely, as rotations accompanied by translations in the internal space. We consider open strings quantized on these backgrounds, distinguishing whether the translational action is parallel or perpendicular to the D-branes. GUT breaking is impossible in the purely perpendicular case, non-local GUT breaking is instead allowed in the purely parallel case. In the latter, the scale of breaking is set by the compactification moduli, and there are no fixed points with reduced gauge symmetry, where dangerous explicit GUT-breaking terms could be located. We investigate the mixed parallel+perpendicular case in a Z 2 xZ 2 ' example, having also a simplified field theory realization. It is a new S 1 /Z 2 xZ 2 ' orbifold-GUT model, with bulk gauge symmetry SU(5)xSU(5) broken locally to the Standard Model gauge group. In spite of the locality of the GUT symmetry breaking, there is no localized contribution to the running of the coupling constants, and the unification scale is completely set by the length of S 1

  15. Werner-Heisenberg-Institut fuer Physik. Annual report 1982

    International Nuclear Information System (INIS)

    1982-12-01

    This annual report contains extended abstracts about the work done at the named institute together with a list of publications, speeches, seminars, and lectures. The work concerns experimental studies on high energy physics at CERN and at the PETRA storagering with the CELLO detector together with some planned experiments on the Tevatron accelerator, developments for future LEP experiments, theoretical studies on grand unification, QCD phenomenology, lattice gauge theories, supergravity, quantum mechanics, and non-relativistic many-body theory, as well as developments of radiation detectors. (HSI) [de

  16. Gauge-Higgs Unification Models in Six Dimensions with S2/Z2 Extra Space and GUT Gauge Symmetry

    Directory of Open Access Journals (Sweden)

    Cheng-Wei Chiang

    2012-01-01

    Full Text Available We review gauge-Higgs unification models based on gauge theories defined on six-dimensional spacetime with S2/Z2 topology in the extra spatial dimensions. Nontrivial boundary conditions are imposed on the extra S2/Z2 space. This review considers two scenarios for constructing a four-dimensional theory from the six-dimensional model. One scheme utilizes the SO(12 gauge symmetry with a special symmetry condition imposed on the gauge field, whereas the other employs the E6 gauge symmetry without requiring the additional symmetry condition. Both models lead to a standard model-like gauge theory with the SU(3×SU(2L×U(1Y(×U(12 symmetry and SM fermions in four dimensions. The Higgs sector of the model is also analyzed. The electroweak symmetry breaking can be realized, and the weak gauge boson and Higgs boson masses are obtained.

  17. Einstein's Last Dream: The Space–Time Unification of Fundamental ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 1. Einstein's Last Dream: The Space – Time Unification of Fundamental Forces. Abdus Salam. Reflections Volume 3 Issue 1 January 1998 pp 81-88. Fulltext. Click here to view fulltext PDF. Permanent link:

  18. Educational Systems and Rising Inequality: Eastern Germany after Unification

    Science.gov (United States)

    von Below, Susanne; Powell, Justin J. W.; Roberts, Lance W.

    2013-01-01

    Educational systems considerably influence educational opportunities and the resulting social inequalities. Contrasting institutional regulations of both structures and contents, the authors present a typology of educational system types in Germany to analyze their effects on social inequality in eastern Germany after unification. After 1990, the…

  19. Towards a Grand Unified Theory of sports performance.

    Science.gov (United States)

    Glazier, Paul S

    2017-12-01

    Sports performance is generally considered to be governed by a range of interacting physiological, biomechanical, and psychological variables, amongst others. Despite sports performance being multi-factorial, however, the majority of performance-oriented sports science research has predominantly been monodisciplinary in nature, presumably due, at least in part, to the lack of a unifying theoretical framework required to integrate the various subdisciplines of sports science. In this target article, I propose a Grand Unified Theory (GUT) of sports performance-and, by elaboration, sports science-based around the constraints framework introduced originally by Newell (1986). A central tenet of this GUT is that, at both the intra- and inter-individual levels of analysis, patterns of coordination and control, which directly determine the performance outcome, emerge from the confluence of interacting organismic, environmental, and task constraints via the formation and self-organisation of coordinative structures. It is suggested that this GUT could be used to: foster interdisciplinary research collaborations; break down the silos that have developed in sports science and restore greater disciplinary balance to the field; promote a more holistic understanding of sports performance across all levels of analysis; increase explanatory power of applied research work; provide stronger rationale for data collection and variable selection; and direct the development of integrated performance monitoring technologies. This GUT could also provide a scientifically rigorous basis for integrating the subdisciplines of sports science in applied sports science support programmes adopted by high-performance agencies and national governing bodies for various individual and team sports. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Who ordered the muon: from families to communities

    International Nuclear Information System (INIS)

    Senjanovic, G.

    1985-01-01

    I review the possibility that the underlying theory of weak interactions possesses a family symmetry, either global or local. The spontaneous symmetry breaking of this symmetry leads to important phenomenological implications: the existence of Goldstone bosons, the familons in the case of global symmetry and the existence of mirror fermions, in the case of local symmetry (in the context of grand unification). Both alternatives will soon be tested

  1. Who ordered the muon. From families to communities

    International Nuclear Information System (INIS)

    Senjanovic, G.

    1985-01-01

    I review the possibility that the underlying theory of weak interactions possesses a family symmetry, either global or local. The spontaneous symmetry breaking of this symmetry leads to important phenomenological implications: the existence of Goldstone bosons, the familons in the case of global symmetry and the existence of mirror fermions, in the case of local symmetry ( in the context of grand unification). Both alternatives will soon be tested. 13 refs

  2. Grand unified supersymmetric Higgs bosons as pseudo-Goldstone particles

    International Nuclear Information System (INIS)

    Barbieri, R.; Dvali, G.; Strumia, A.

    1993-01-01

    We reconsider the possibility that the Higgs doublet responsible for the breaking of the electroweak gauge group be quasi-Goldstone bosons of a spontaneously broken approximate global symmetry of the theory. Supersymmetric SU(5) and SO(10) gauge models are discussed. The main phenomenological consequence of this viewpoint is the possible existence at the Fermi scale of a quasi-stable particle, most likely a Lorentz scalar, with the same colour and charge as a down quark. Its existence is a generic feature of models based on SO(10). The associated phenomoenological is illustrated. We also show how the phenomenology of the minimal SU(5) theory, already proposed, gets tightly constrained by the consideration of coupling constant unification without any assumption, otherwise crucial, on the superheavy threshold effects. (orig.)

  3. A4 family symmetry and quark-lepton unification

    International Nuclear Information System (INIS)

    King, Stephen F.; Malinsky, Michal

    2007-01-01

    We present a model of quark and lepton masses and mixings based on A 4 family symmetry, a discrete subgroup of an SO(3) flavour symmetry, together with Pati-Salam unification. It accommodates tri-bimaximal neutrino mixing via constrained sequential dominance with a particularly simple vacuum alignment mechanism emerging through the effective D-term contributions to the scalar potential

  4. Cosmic string solution in a Born-Infeld type theory of gravity

    International Nuclear Information System (INIS)

    Rocha, W.J. da; Guimaraes, M.E.X.

    2009-01-01

    Full text. Advances in the formal structure of string theory point to the emergence, and necessity, of a scalar-tensorial theory of gravity. It seems that, at least at high energy scales, the Einstein's theory is not enough to explain the gravitational phenomena. In other words, the existence of a scalar (gravitational) field acting as a mediator of the gravitational interaction together with the usual purely rank-2 tensorial field is, indeed, a natural prediction of unification models as supergravity, superstrings and M-theory. This type of modified gravitation was first introduced in a different context in the 60's in order to incorporate the Mach's principle into relativity, but nowadays it acquired different sense in cosmology and gravity theories. Although such unification theories are the most acceptable, they all exist in higher dimensional spaces. The compactification from these higher dimensions to the 4-dimensional physics is not unique and there exist many effective theories of gravity which come from the unification process. Each of them must, of course, satisfy some predictions. Here, in this paper, we will deal with one of them. The so-called NDL theory. One important assumption in General Relativity is that all field interact in the same way with gravity. This is the so called Strong Equivalence Principle (SEP). It is well known, with good accuracy, that this is true when we concern with matter to matter interaction, i.e, the Weak Equivalence Principle(WEP) is tested. But, until now, there is no direct observational confirmation of this affirmation to the gravity to gravity interaction. In an extension of the field theoretical description of General Relativity constructed by is used to propose an alternative field theory of gravity. In this theory gravitons propagate in a different spacetime. The velocity of propagation of the gravitational waves in this theory does not coincide with the General Relativity predictions. (author)

  5. arXiv Gauge Backgrounds and Zero-Mode Counting in F-Theory

    CERN Document Server

    Bies, Martin; Weigand, Timo

    2017-11-14

    Computing the exact spectrum of charged massless matter is a crucial step towards understanding the effective field theory describing F-theory vacua in four dimensions. In this work we further develop a coherent framework to determine the charged massless matter in F-theory compactified on elliptic fourfolds, and demonstrate its application in a concrete example. The gauge background is represented, via duality with M-theory, by algebraic cycles modulo rational equivalence. Intersection theory within the Chow ring allows us to extract coherent sheaves on the base of the elliptic fibration whose cohomology groups encode the charged zero-mode spectrum. The dimensions of these cohomology groups are computed with the help of modern techniques from algebraic geometry, which we implement in the software gap. We exemplify this approach in models with an Abelian and non-Abelian gauge group and observe jumps in the exact massless spectrum as the complex structure moduli are varied. An extended mathematical appendix gi...

  6. Philosophical introduction to set theory

    CERN Document Server

    Pollard, Stephen

    2015-01-01

    The primary mechanism for ideological and theoretical unification in modern mathematics, set theory forms an essential element of any comprehensive treatment of the philosophy of mathematics. This unique approach to set theory offers a technically informed discussion that covers a variety of philosophical issues. Rather than focusing on intuitionist and constructive alternatives to the Cantorian/Zermelian tradition, the author examines the two most important aspects of the current philosophy of mathematics, mathematical structuralism and mathematical applications of plural reference and plural

  7. The string unification of gauge couplings and gauge kinetic mixings

    International Nuclear Information System (INIS)

    Hattori, Chuichiro; Matsuda, Masahisa; Matsuoka, Takeo; Mochinaga, Daizo.

    1993-01-01

    In the superstring models we have not only the complete 27 multiplets of E 6 but also extra incomplete (27+27-bar) chiral supermultiplets being alive at low energies. Associated with these additional multiplets, when the gauge symmetry contains more than one U(1) gauge group, there may exist gauge kinetic mixings among these U(1) gauge groups. In such cases the effect of gauge kinetic mixings should be incorporated into the study of unification of gauge couplings. We study these interesting effects systematically in these models. The string threshold effect is also taken into account. It is found that in the four-generation models we do not have an advisable solution of string unification of gauge couplings consistent with experimental values at the electroweak scale. We also discuss the possible scenarios to solve this problem. (author)

  8. Radiative breaking of cosmologically acceptable grand unified theories

    International Nuclear Information System (INIS)

    Gato, B.; Leon, J.; Quiros, M.

    1984-01-01

    We present a cosmologically acceptable grand unified model where the breaking of SU(5) proceeds through radiative corrections induced by supergravity soft-breaking terms. The breaking scale is determined by dimensional transmutation. The model is compatible with the radiative breaking of SU(2)sub(L)xU(1)sub(Y) which provides an experimentally accessible low energy particle spectrum and small top quark mass. (orig.)

  9. From physics to metaphysics. Physical unification and string approach; Von der Physik zur Metaphysik. Physikalische Vereinheitlichung und Stringansatz

    Energy Technology Data Exchange (ETDEWEB)

    Hedrich, R.

    2007-07-01

    In spite the string approach as attempt of a nomologically unified comprehension of all interactions inclusively the gravitation exists already over three decades the physical principles on which it is based are yet completely unclear; and not the most unimportant empirically provable quantitative prediction exists. Without empirical data, which would be incompatible with the stablished theories - quantum-field theoretical standard model anf general relativity - only the conceptual incompatibility of both together with the unification idea yields a motivation for the string approach. By this however physics threatens to exceed under consequent continuation of their hitherto successful strategies the methodological framework of empirical sciences.

  10. Family unification within SO(15)

    International Nuclear Information System (INIS)

    Enqvist, K.; Maalampi, J.

    1981-01-01

    We present a model for the unification of fermion families based on the gauge symmetry SO(15). It is a minimal SO(n) model which can accommodate the known fermions within a single irreducible representation. The model predicts four ordinary fermion families and four families of mirror fermions. The latter have V + A weak interactions, and their mass scale is predicted to be 10 2 GeV/c 2 . We argue that radiative corrections to the fermion masses can cause non-negligible mixing between ordinary and mirror fermions. The implications of these mixings for the weak interaction phenomenology and solar neutrinos are discussed. (orig.)

  11. Non-Higgsable clusters for 4D F-theory models

    International Nuclear Information System (INIS)

    Morrison, David R.; Taylor, Washington

    2015-01-01

    We analyze non-Higgsable clusters of gauge groups and matter that can arise at the level of geometry in 4D F-theory models. Non-Higgsable clusters seem to be generic features of F-theory compactifications, and give rise naturally to structures that include the nonabelian part of the standard model gauge group and certain specific types of potential dark matter candidates. In particular, there are nine distinct single nonabelian gauge group factors, and only five distinct products of two nonabelian gauge group factors with matter, including SU(3)×SU(2), that can be realized through 4D non-Higgsable clusters. There are also more complicated configurations involving more than two gauge factors; in particular, the collection of gauge group factors with jointly charged matter can exhibit branchings, loops, and long linear chains.

  12. Searches for new phenomena in leptonic final states using the ATLAS detector

    CERN Document Server

    Muskinja, Miha; The ATLAS collaboration

    2018-01-01

    Resonances decaying to leptons are very common in various BSM theories such as the Grand Unification theory, Left-Right Symmetric model, Sequential Standard Model, Two-Higgs-Doublet model, Higgs triplet, and many more. Final states with leptons have lower backgrounds and are something to trigger on. Furthermore, the detector resolution allows a good measurement of the invariant mass of BSM resonances decaying to electrons and muons. The talk covers several searches for new resonances decaying into electrons and muons and presents the technical challenges, along with the tangible solutions, that these searches are facing.

  13. Challenging particle physics as path to truth

    CERN Multimedia

    Johnson, G

    2001-01-01

    Particle physicist's ultimate goal is 'grand unification' - describing the four forces observed today - electromagnetism, weak and strong nuclear forces and gravity with just a single law, expressable as a few concise equations. But some solid state physicists are now contesting the validity of this approach, arguing that many forms of matter cannot be described solely in terms of fundamental particle interactions - when systems are very complex, new and independent laws emerge. They propose that there is no one theory of everything, just a lot of theories of things.

  14. Unitary unified field theories

    International Nuclear Information System (INIS)

    Sudarshan, E.C.G.

    1976-01-01

    This is an informal exposition of some recent developments. Starting with an examination of the universality of electromagnetic and weak interactions, the attempts at their unification are outlined. The theory of unitary renormalizable self-coupled vector mesons with dynamical sources is formulated for a general group. With masses introduced as variable parameters it is shown that the theory so defined is indeed unitary. Diagrammatic rules are developed in terms of a chosen set of fictitious particles. A number of special examples are outlined including a theory with strongly interacting vector and axial vector mesons and weak mesons. Applications to weak interactions of strange particles is briefly outlined. (Auth.)

  15. A supersymmetric grand unified theory of flavour with PSL2(7)xSO(10)

    International Nuclear Information System (INIS)

    King, Stephen F.; Luhn, Christoph

    2010-01-01

    We construct a realistic Supersymmetric Grand Unified Theory of Flavour based on PSL 2 (7)xSO(10), where the quarks and leptons in the 16 of SO(10) are assigned to the complex triplet representation of PSL 2 (7), while the flavons are assigned to a combination of sextets and anti-triplets of PSL 2 (7). Using a D-term vacuum alignment mechanism, we require the flavon sextets of PSL 2 (7) to be aligned along the 3-3 direction leading to the third family Yukawa couplings, while the flavon anti-triplets describe the remaining Yukawa couplings. Other sextets are aligned along the neutrino flavour symmetry preserving directions leading to tri-bimaximal neutrino mixing via a type II see-saw mechanism, with predictions for neutrinoless double beta decay and cosmology.

  16. Study of Antigravity in an F(R) Model and in Brans-Dicke Theory with Cosmological Constant

    OpenAIRE

    Oikonomou, V. K.; Karagiannakis, N.

    2014-01-01

    We study antigravity, that is having an effective gravitational constant with a negative sign, in scalar-tensor theories originating from $F(R)$-theory and in a Brans-Dicke model with cosmological constant. For the $F(R)$ theory case, we obtain the antigravity scalar-tensor theory in the Jordan frame by using a variant of the Lagrange multipliers method and we numerically study the time dependent effective gravitational constant. As we shall demonstrate by using a specific $F(R)$ model, altho...

  17. Unification of reactor elastomeric sealing based on material

    International Nuclear Information System (INIS)

    Sinha, N.K.; Raj, Baldev

    2012-01-01

    The unification of elastomeric sealing applications of Indian nuclear reactors based on a few qualified fluoroelastomer/perfluoroelastomer compounds and standardized approaches for finite element analysis (FEA) based design, manufacturing process and antifriction coatings is discussed. It is shown that the advance polymer architecture based Viton ® formulation developed for inflatable seals of 500 MWe Prototype Fast Breeder Reactor (PFBR) and its four basic variations can encompass other sealing applications of PFBR with minimum additional efforts on development and validation. Changing the blend ratio of Viton ® GBL 200S and 600S in inflatable seal formulation could extend its use to Pressurized Heavy Water Reactors (PHWRs). The higher operating temperature of Advanced Heavy Water Reactor (AHWR) seals expands the choice to perfluoroelastomers. FEA based on plane-strain/axisymmetric modeling (with Mooney–Rivlin as the basic constitutive model), seal manufacture by cold feed extrusion and injection molding as well as plasma Teflon-like coating belonging to two variations obtained from the development of inflatable seals provide the necessary standardization for unification. The gains in simplification of design, development and operation of seals along with the enhancements of safety and reliability are expected to be substantial.

  18. Aspects of Flavour and Supersymmetry in F-theory GUTs

    CERN Document Server

    Conlon, Joseph P; 10.1007

    2009-01-01

    We study the constraints of supersymmetry on flavour in recently proposed models of F-theory GUTs. We relate the topologically twisted theory to the canonical presentation of eight-dimensional super Yang-Mills and provide a dictionary between the two. We describe the constraints on Yukawa couplings implied by holomorphy of the superpotential in the effective 4-dimensional supergravity theory, including the scaling with \\alpha_{GUT}. Taking D-terms into account we solve explicitly to second order for wavefunctions and Yukawas due to metric and flux perturbations and find a rank-one Yukawa matrix with no subleading corrections.

  19. Unification of three linear models for the transient visual system

    NARCIS (Netherlands)

    Brinker, den A.C.

    1989-01-01

    Three different linear filters are considered as a model describing the experimentally determined triphasic impulse responses of discs. These impulse responses arc associated with the transient visual system. Each model reveals a different feature of the system. Unification of the models is

  20. Law behind second law of thermodynamics - unification with cosmology

    International Nuclear Information System (INIS)

    Nielsen, Holger B.; Ninomiya, Masao

    2006-01-01

    In an abstract setting of a general classical mechanical system as a model for the universe we set up a general formalism for a law behind the second law of thermodynamics, i.e. really for 'initial conditions'. We propose a unification with the other laws by requiring similar symmetry and locality properties

  1. Strong coupling in F-theory and geometrically non-Higgsable seven-branes

    Directory of Open Access Journals (Sweden)

    James Halverson

    2017-06-01

    Full Text Available Geometrically non-Higgsable seven-branes carry gauge sectors that cannot be broken by complex structure deformation, and there is growing evidence that such configurations are typical in F-theory. We study strongly coupled physics associated with these branes. Axiodilaton profiles are computed using Ramanujan's theories of elliptic functions to alternative bases, showing explicitly that the string coupling is O(1 in the vicinity of the brane; that it sources nilpotent SL(2,Z monodromy and therefore the associated brane charges are modular; and that essentially all F-theory compactifications have regions with order one string coupling. It is shown that non-perturbative SU(3 and SU(2 seven-branes are related to weakly coupled counterparts with D7-branes via deformation-induced Hanany–Witten moves on (p,q string junctions that turn them into fundamental open strings; only the former may exist for generic complex structure. D3-brane near these and the Kodaira type II seven-branes probe Argyres–Douglas theories. The BPS states of slightly deformed theories are shown to be dyonic string junctions.

  2. Neutrino masses and b - τ unification in the supersymmetric standard model

    International Nuclear Information System (INIS)

    Vissani, F.; Smirnov, A.Yu.

    1994-05-01

    There are several indications that the Majorana masses of the right-handed neutrino components, M R , are at the intermediate scale: M R ∼ (10 10 - 10 12 ) GeV or even lighter. The renormalization effects due to large Yukawa couplings of neutrinos from region of momenta M R G are studied in the supersymmetric standard model. It is shown that neutrino renormalization effect can increase the m b /m τ ratio up to (10/15)%. This strongly disfavors m b - m τ unification for low values of tan β s . Lower bound on M R and tan β from the b - τ unification condition were found. The implications of the results to the see-saw mechanism of the neutrino mass generation are discussed. (author). 17 refs, 4 figs

  3. Implications of extreme flatness in a general f(R theory

    Directory of Open Access Journals (Sweden)

    Michał Artymowski

    2016-09-01

    Full Text Available We discuss a modified gravity theory defined by f(R=∑nlαnM2(1−nRn. We consider both finite and infinite number of terms in the series while requiring that the Einstein frame potential of the theory has a flat area around any of its stationary points. We show that the requirement of maximally flat stationary point leads to the existence of the saddle point (local maximum for even (odd l. In both cases for l→∞ one obtains the Starobinsky model with small, exponentially suppressed corrections. Besides the GR minimum the Einstein frame potential has an anti de Sitter vacuum. However we argue that the GR vacuum is absolutely stable and AdS can be reached neither via classical evolution nor via quantum tunnelling. Our results show that a Starobinsky-like model is the only possible realisation of f(R theory with an extremely flat area in the Einstein frame potential.

  4. Building Theory for Management Science and Practice

    DEFF Research Database (Denmark)

    Sanchez, Ron; Heene, Aimé

    2017-01-01

    In this paper we examine some fundamental epistemological issues in building theory for applied management science, by which we mean theory that can be usefully applied in a scientific approach to management research and practice. We first define and distinguish “grand theory” from “mid......-range theory” in the social and management sciences. We then elaborate and contrast epistemologies for (i) building “grand theory” intended to be applicable to all cases and contexts, and (ii) building “mid-range theory” intended to apply to specific kinds of contexts. We illustrate the epistemological...... challenges in building grand theory in management science by considering important differences in the abilities of two “grand theories” in strategic management – industry structure theory and firm resources theory – to support development of conceptually consistent models and propositions for empirical...

  5. THE COMPLETION OF THE CHURCH UNIFICATION FROM 1700-1701 UNDER THE BISHOP ATANASIE

    Directory of Open Access Journals (Sweden)

    Florin-Alin OROS

    2013-11-01

    Full Text Available The religious unification around year 1700, betweeen a part of the Orthodox believers from Transylvania and the Church of Rome, of Catholic religion, had represented an event that left a profound spiritual mark on the Romanian and Transylvanian population. The efforts for a Unification had started under the Orthodox bishop from Transylvania, Teofil (1692-1697, a part of the Orthodox priests being willing to accept it for a series of rights and benefits. These efforts could not be accomplished because of the sudden death of the bishop in 1697. As a result of the endeavours of the next bishop of the Romanians, Atanasie, a part of the Orthodox believers had joined the new Greek-Catholic communion around 1700-1701. There is no doubt that this historical and religious endeavour was not an easy one, Atanasie being compelled to „sail” in the muddy waters of the religious structure in Transylvania. This oscillation between the Orthodox and Catholic religions, under the strict supervision of the Imperial authorities from Wien, had triggered the completion of the religious Unification at the beginning of the 18th century and the development of the Greek-Catholic church in Transylvania.

  6. Casa Grande Ruins National Monument acoustical monitoring 2010

    Science.gov (United States)

    2014-11-01

    During September 2010, The Volpe Center collected baseline acoustical data at Casa Grande National Monument (CAGR), at one site for 28 days. The baseline data collected during this period will help park managers and planners estimate the effects of f...

  7. Elementary particle physics

    International Nuclear Information System (INIS)

    Kenyon, I.R.

    1987-01-01

    Intended for undergraduate and postgraduate students the book concentrates on the 'standard model' and the gauge symmetries. Leptons, quarks and forces are introduced at the beginning, followed by experimental techniques which have found them. Gauge theories are dealt with in order of increasing complexity - quantum electrodynamics and the gauge principle, symmetries and conservation laws, colour and quantum chromodynamics, the V - A theory of weak interactions and electroweak unification. Attention is then focussed on the hadrons. Deep inelastic scattering of hadrons is explained first, then hadron spectroscopy and then hadron interactions. Current developments beyond the Standard model - grand unification, supersymmetry, cosmology and gravitation -are discussed in the final chapter. The appendices cover kinematic, cross-section and decay-rate formulae, Breit-Wigner resonances, some Clebsch-Gordan coefficient tables, a table of particle properties, exercises and answers, and the Dirac equation. There is also an appendix on calculating scattering amplitudes for fermion + fermion going to fermion + fermion. A list of references is given. (U.K.)

  8. Harmonious graphics generating based on the 1/f function theory

    International Nuclear Information System (INIS)

    Mao Xia; Xue Yuli; Cheng, L.-L.; Sun Yun

    2007-01-01

    In the 1970s, Richard Voss and John Clarke researched the actual audio physical sound of music. There are three types of noise: white noise, 1/f noise, and Brownian motion noise (1/f 2 ). 1/f noise is found to be most pleasing to human ears. White noise is too random and Brownian noise is too correlated. Similarly, for 2-dimensional sources such as graphics and images, three characteristics of monotonous, harmony and muss are also observed. The 1/f fluctuation theory provides a good way to generate affective signals both for 1-dimensional and 2-dimensional signals. This paper provides an algorithm which can generate affective patterns or graphics and obey the criteria of affective information processing

  9. Reconstructing a f ( R ) theory from the α-Attractors

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, T.; Fabris, J. C.; Piattella, O. F., E-mail: tays.andrade@aluno.ufes.br, E-mail: oliver.piattella@pq.cnpq.br, E-mail: fabris@pq.cnpq.br [Department of Physics, Universidade Federal do Espírito Santo, avenida Fernando Ferrari 514, 29075-910 Vitória, Espírito Santo (Brazil)

    2017-09-01

    We show an analogy at high curvature between a f ( R ) = R + aR {sup n} {sup −} {sup 1} + bR {sup 2} theory and the α-Attractors. We calculate the expressions of the parameters a , b and n as functions of α and the predictions of the model f ( R ) = R + aR {sup n} {sup −} {sup 1} + bR {sup 2} on the scalar spectral index n {sub s} and the tensor-to-scalar ratio r . We find that the power law correction R {sup n} {sup −} {sup 1} allows for a production of gravitational waves enhanced with respect to the one in the Starobinsky model, while maintaining a viable prediction on n {sub s}. We numerically reconstruct the full α-Attractors class of models testing the goodness of our high-energy approximation f ( R ) = R + aR {sup n} {sup −} {sup 1} + bR {sup 2}. Moreover, we also investigate the case of a single power law f ( R ) = γ R {sup 2} {sup −} {sup δ} theory, with γ and δ free parameters. We calculate analytically the predictions of this model on the scalar spectral index n {sub s} and the tensor-to-scalar ratio r and the values of δ which are allowed from the current observational results. We find that −0.015 < δ < 0.016, confirming once again the excellent agreement between the Starobinsky model and observation.

  10. Alternative gravity theories

    International Nuclear Information System (INIS)

    Francaviglia, M.

    1990-01-01

    Although general relativity is a well-established discipline the theory deserves efforts aimed at producing alternative or more general frameworks for investigating the classical properties of gravity. These are either devoted to producing alternative viewpoints or interpretations of standard general relativity, or at constructing, discussing and proposing experimental tests for alternative descriptions of the dynamics of the gravitational field and its interaction (or unification) with external matter fields. Classical alternative theories of gravitation can roughly classified as follows; theories based on a still 4-dimensional picture, under the assumption that the dynamics of the gravitational field is more complicated than Einstein's and theories based on higher-dimensional pictures. This leads to supergravity and strings which are not included here. Theories based on higher-dimensional pictures on the assumption that space-time is replaced by a higher-dimensional manifold. Papers on these classifications are reviewed. (author)

  11. E(lementary) Strings in Six-Dimensional Heterotic F-Theory

    OpenAIRE

    Choi, Kang-Sin; Rey, Soo-Jong

    2017-01-01

    Using E-strings, we can analyze not only six-dimensional superconformal field theories but also probe vacua of non-perturabative heterotic string. We study strings made of D3-branes wrapped on various two-cycles in the global F-theory setup. We claim that E-strings are elementary in the sense that various combinations of E-strings can form M-strings as well as heterotic strings and new kind of strings, called G-strings. Using them, we show that emissions and combinations of heterotic small in...

  12. Dual field theory of strong interactions

    International Nuclear Information System (INIS)

    Akers, D.

    1987-01-01

    A dual field theory of strong interactions is derived from a Lagrangian of the Yang-Mills and Higgs fields. The existence of a magnetic monopole of mass 2397 MeV and Dirac charge g = (137/2)e is incorporated into the theory. Unification of the strong, weak, and electromagnetic forces is shown to converge at the mass of the intermediate vector boson W/sup +/-/. The coupling constants of the strong and weak interactions are derived in terms of the fine-structure constant α = 1/137

  13. Unification of Radio Galaxies and their Accretion Jet Properties

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... We investigate the relation between black hole mass, bh, and jet power, jet, for a sample of BL Lacs and radio quasars. We find that BL Lacs are separated from radio quasars by the FR I/II dividing line in bh-jet plane, which strongly supports the unification scheme of FR I/BL Lac and FR II/radio ...

  14. Unification of Radio Galaxies and their Accretion Jet Properties ...

    Indian Academy of Sciences (India)

    Abstract. We investigate the relation between black hole mass, Mbh, and jet power, Qjet, for a sample of BL Lacs and radio quasars. We find that BL Lacs are separated from radio quasars by the FR I/II dividing line in Mbh–Qjet plane, which strongly supports the unification scheme of FR. I/BL Lac and FR II/radio quasar.

  15. Natural fermion mass hierarchy and mixings in family unification

    International Nuclear Information System (INIS)

    Dent, James B.; Feger, Robert; Kephart, Thomas W.; Nandi, S.

    2011-01-01

    We present an SU(9) model of family unification with three light chiral families, and a natural hierarchy of charged fermion masses and mixings. The existence of singlet right handed neutrinos with masses about two orders of magnitude smaller than the GUT scale, as needed to understand the light neutrinos masses via the see-saw mechanism, is compelling in our model.

  16. Supersymmetric moduli stabilization and high-scale inflation

    International Nuclear Information System (INIS)

    Buchmueller, Wilfried; Wieck, Clemens; Winkler, Martin Wolfgang

    2014-04-01

    We study the back-reaction of moduli fields on the inflaton potential in generic models of F-term inflation. We derive the moduli corrections as a power series in the ratio of Hubble scale and modulus mass. The general result is illustrated with two examples, hybrid inflation and chaotic inflation. We find that in both cases the decoupling of moduli dynamics and inflation requires moduli masses close to the scale of grand unification. For smaller moduli masses the CMB observables are strongly affected.

  17. Time in Quantum Cosmology of FRW f(R Theories

    Directory of Open Access Journals (Sweden)

    C. Ramírez

    2018-01-01

    Full Text Available The time problem is a problem of canonical quantum gravity that has long been known about; it is related to the relativistic invariance and the consequent absence of an explicit time variable in the quantum equations. This fact complicates the interpretation of the wave function of the universe. Following proposals to assign the clock function to a scalar field, we look at the scalar degree of freedom contained in f ( R theories. For this purpose we consider a quadratic f ( R theory in an equivalent formulation with a scalar field, with a FRW metric, and consider its Wheeler-DeWitt equation. The wave function is obtained numerically and is consistent with the interpretation of the scalar field as time by means of a conditional probability, from which an effective time-dependent wave function follows. The evolution the scale factor is obtained by its mean value, and the quantum fluctuations are consistent with the Heisenberg relations and a classical universe today.

  18. Light bending in F [ g (□) R ] extended gravity theories

    Science.gov (United States)

    Giacchini, Breno L.; Shapiro, Ilya L.

    2018-05-01

    We show that in the weak field limit the light deflection alone cannot distinguish between different R + F [ g (□) R ] models of gravity, where F and g are arbitrary functions. This does not imply, however, that in all these theories an observer will see the same deflection angle. Owed to the need to calibrate the Newton constant, the deflection angle may be model-dependent after all necessary types of measurements are taken into account.

  19. Unified cosmic history in modified gravity: From F(R) theory to Lorentz non-invariant models

    Science.gov (United States)

    Nojiri, Shin'Ichi; Odintsov, Sergei D.

    2011-08-01

    The classical generalization of general relativity is considered as the gravitational alternative for a unified description of the early-time inflation with late-time cosmic acceleration. The structure and cosmological properties of a number of modified theories, including traditional F(R) and Hořava-Lifshitz F(R) gravity, scalar-tensor theory, string-inspired and Gauss-Bonnet theory, non-local gravity, non-minimally coupled models, and power-counting renormalizable covariant gravity are discussed. Different representations of and relations between such theories are investigated. It is shown that some versions of the above theories may be consistent with local tests and may provide a qualitatively reasonable unified description of inflation with the dark energy epoch. The cosmological reconstruction of different modified gravities is provided in great detail. It is demonstrated that eventually any given universe evolution may be reconstructed for the theories under consideration, and the explicit reconstruction is applied to an accelerating spatially flat Friedmann-Robertson-Walker (FRW) universe. Special attention is paid to Lagrange multiplier constrained and conventional F(R) gravities, for latter F(R) theory, the effective ΛCDM era and phantom divide crossing acceleration are obtained. The occurrences of the Big Rip and other finite-time future singularities in modified gravity are reviewed along with their solutions via the addition of higher-derivative gravitational invariants.

  20. Whitehead's Multiverse

    Science.gov (United States)

    McHenry, Leemon

    2012-09-01

    Alfred North Whitehead advanced a version of multiverse theory in 19291 that bears a remarkable affinity to the revolutionary ideas of current cosmological speculation.2 He postulated his theory for some of the very same reasons as those advanced today by leading cosmologists and physicists such as Martin Rees, Lee Smolin, Stephen Hawking, Max Tegmark and Steven Weinberg, but his theory has largely gone unnoticed. While Whitehead knew nothing of the great advances in big bang theory, expansion, inflation and the unification of physics in post-Hubble cosmology when he wrote Process and Reality in the 1920s, he sought to explain the origin of our universe from its predecessor and to unify the fragmentary theories of physics into a grand theory.

  1. The unification of powerful radio-loud AGN: the multi-wavelength balance

    NARCIS (Netherlands)

    Podigachoski, Pece; Barthel, Peter; Haas, Martin; Leipski, Christian; Wilkes, Belinda; Rocca-Volmerange, Brigitte; Drouart, Guillaume

    2016-01-01

    Powerful radio-loud AGN, by virtue of their optically-thin low-frequency radio emission, represent unique targets in orientation-based unification studies, and in searches for orientation indicators and orientation invariants. Central in these efforts is the landmark Third Cambridge Catalog of Radio

  2. Kaluza-Klein theories. 21

    International Nuclear Information System (INIS)

    Maheshwari, A.

    1989-01-01

    The old Kaluza-Klein theory in five dimensions for unification of electromagnetism and gravitation is discussed and put in a modern perspective so that one can now generalize the approach to unify arbitrary (non-Abelian) gauge fields with gravitation. The internal and spacetime symmetries are unified by making the internal symmetries as spacetime symmetries of 'unobservable' dimensions. This necessitates the introduction of higher dimensions - eleven in particular to accommodate the standard theory. But one has to face up the fate of the extra dimensions. Spontaneous compactification is one solution and this is treated in detail, as also is the harmonic expansions necessary to obtain the particle spectrum of Kaluza-Klein theories. The chapter ends with a discussion of the problem of chiral fermions in these theories. (author). 16 refs

  3. Solar System constraints on a cosmologically viable f(R) theory

    Energy Technology Data Exchange (ETDEWEB)

    Bisabr, Yousef, E-mail: y-bisabr@srttu.ed [Department of Physics, Shahid Rajaee Teacher Training University, Lavizan, Tehran 16788 (Iran, Islamic Republic of)

    2010-01-18

    Recently, a model f(R) theory is proposed (Miranda et al. (2009)) which is cosmologically viable and distinguishable from LAMBDACDM. We use chameleon mechanism to investigate viability of the model in terms of Solar System experiments.

  4. On discrete geometrodynamical theories in physics

    International Nuclear Information System (INIS)

    Towe, J.P.

    1988-01-01

    In this dissertation the author considers two topological-geometrical models (based upon a single suggestive formalism) in which a geometrodynamics is both feasible and pedagogically advantageous. Specifically he considers the topology which is constituted by the real domains of the two broad classes of rotation groups: those characterized by the commutator and anti-commutator algebras. He then adopts a Riemannian geometric structure and shows that the monistically geometric interpretation of this formalism restricts displacements on the proposed manifold to integral multiples of universal constant. Secondly, he demonstrates that in the context under consideration, this constraint affects a very interesting ontological reduction: the unification of quantum mechanics with a discrete, multidimensional extension of general relativity. A particularly interesting features of this unification is that is includes and requires the choice of an SL (2,R) direct-product SU (3)-symmetric realization of the proposed, generic formalism which is a lattice of spins ℎ and ℎ/2. If the vertices of this lattice are associated with the fundamental particles, then the resulting theory predicts and precludes the same interactions as the standard supersymmetry theory. In addition to the ontological reduction which is provided, and the restriction to supersymmetry, the proposed theory may also represent a scientifically useful extension of conventional theory in that it suggests a means of understanding the apparently large energy productions of the quasars and relates Planck's constant to the size of the universe

  5. MUC (Memory, Unification, Control and beyond

    Directory of Open Access Journals (Sweden)

    Peter eHagoort

    2013-07-01

    Full Text Available A neurobiological model of language is discussed that overcomes the shortcomings of the classical Wernicke-Lichtheim-Geschwind model. It is based on a subdivision of language processing into three components: Memory, Unification, and Control. The functional components as well as the neurobiological underpinnings of the model are discussed. In addition, the need for extension of the model beyond the classical core regions for language is shown. Attentional networks as well as networks for inferential processing are crucial to realize language comprehension beyond single word processing and beyond decoding propositional content. It is shown that this requires the dynamic interaction between multiple brain regions.

  6. Unification of fuel elements for research reactors

    International Nuclear Information System (INIS)

    Vatulyn, A.V.; Stetskyi, Y.A.; Dobrikova, I.V.

    1997-01-01

    To the purpose of fuel elements unification the possibility of rod fuel assembly (FA) using in the cores of research reactors have been considered in this paper. The calculation results of geometric, hydraulic and thermotechnical parameters of rod assembly are submitted. Several designs of finned square fuel element and fuel assembly are proposed on base of analysis of rod FA characteristics in compare of tube ones. The fuel elements specimens and the model assembly are manufactured. The developed designs are the basis for further optimization after neutron-physical calculations of cores. (author)

  7. Global F-theory GUTs

    Energy Technology Data Exchange (ETDEWEB)

    Blumenhagen, Ralph; /Munich, Max Planck Inst.; Grimm, Thomas W.; /Bonn U.; Jurke, Benjamin; /Munich, Max Planck Inst.; Weigand, Timo; /SLAC

    2010-08-26

    We construct global F-theory GUT models on del Pezzo surfaces in compact Calabi-Yau fourfolds realized as complete intersections of two hypersurface constraints. The intersections of the GUT brane and the flavour branes as well as the gauge flux are described by the spectral cover construction. We consider a split S[U(4) x U(1){sub X}] spectral cover, which allows for the phenomenologically relevant Yukawa couplings and GUT breaking to the MSSM via hypercharge flux while preventing dimension-4 proton decay. General expressions for the massless spectrum, consistency conditions and a new method for the computation of curvature-induced tadpoles are presented. We also provide a geometric toolkit for further model searches in the framework of toric geometry. Finally, an explicit global model with three chiral generations and all required Yukawa couplings is defined on a Calabi-Yau fourfold which is fibered over the del Pezzo transition of the Fano threefold P{sup 4}.

  8. Global F-theory GUTs

    International Nuclear Information System (INIS)

    Blumenhagen, Ralph; Grimm, Thomas W.; Jurke, Benjamin; Weigand, Timo

    2010-01-01

    We construct global F-theory GUT models on del Pezzo surfaces in compact Calabi-Yau fourfolds realized as complete intersections of two hypersurface constraints. The intersections of the GUT brane and the flavour branes as well as the gauge flux are described by the spectral cover construction. We consider a split S[U(4)xU(1) X ] spectral cover, which allows for the phenomenologically relevant Yukawa couplings and GUT breaking to the MSSM via hypercharge flux while preventing dimension-4 proton decay. General expressions for the massless spectrum, consistency conditions and a new method for the computation of curvature-induced tadpoles are presented. We also provide a geometric toolkit for further model searches in the framework of toric geometry. Finally, an explicit global model with three chiral generations and all required Yukawa couplings is defined on a Calabi-Yau fourfold which is fibered over the del Pezzo transition of the Fano threefold P 4 [4].

  9. Warm inflation in f(G) theory of gravity

    Energy Technology Data Exchange (ETDEWEB)

    Sharif, M., E-mail: msharif.math@pu.edu.pk; Ikram, A., E-mail: ayeshamaths91@gmail.com [University of the Punjab, Quaid-e-Azam Campus, Department of Mathematics (Pakistan)

    2016-07-15

    The aim of this paper is to explore warm inflation in the background of f(G) theory of gravity using scalar fields for the FRW universe model. We construct the field equations under slow-roll approximations and evaluate the slow-roll parameters, scalar and tensor power spectra and their corresponding spectral indices using viable power-law model. These parameters are evaluated for a constant as well as variable dissipation factor during intermediate and logamediate inflationary epochs. We also find the number of e-folds and tensor- scalar ratio for each case. The graphical behavior of these parameters proves that the isotropic model in f(G) gravity is compatible with observational Planck data.

  10. Solar System constraints on a cosmologically viable f(R) theory

    International Nuclear Information System (INIS)

    Bisabr, Yousef

    2010-01-01

    Recently, a model f(R) theory is proposed (Miranda et al. (2009)) which is cosmologically viable and distinguishable from ΛCDM. We use chameleon mechanism to investigate viability of the model in terms of Solar System experiments.

  11. Domain walls and fermion scattering in grand unified models

    International Nuclear Information System (INIS)

    Steer, D.A.; Vachaspati, T.

    2006-01-01

    Motivated by grand unification, we study the properties of domain walls formed in a model with SU(5)xZ 2 symmetry which is spontaneously broken to SU(3)xSU(2)xU(1)/Z 6 , and subsequently to SU(3)xU(1)/Z 3 . Even after the first stage of symmetry breaking, the SU(3) symmetry is broken to SU(2)xU(1)/Z 2 on the domain wall. In a certain range of parameters, flux tubes carrying color- and hyper-charge live on the domain wall and appear as 'boojums' when viewed from one side of the domain wall. Magnetic monopoles are also formed in the symmetry breaking and those carrying color and hyper-charge can be repelled from the wall due to the Meissner effect, or else their magnetic flux can penetrate the domain wall in quantized units. After the second stage of symmetry breaking, fermions can transmute when they scatter with the domain wall, providing a simpler version of fermion-monopole scattering: for example, neutrinos can scatter into d-quarks, leaving behind electric charge and color which is carried by gauge field excitations living on the domain wall

  12. Calculating corrections in F-theory from refined BPS invariants and backreacted geometries

    Energy Technology Data Exchange (ETDEWEB)

    Poretschkin, Maximilian

    2015-07-01

    This thesis presents various corrections to F-theory compactifications which rely on the computation of refined Bogomol'nyi-Prasad-Sommerfield (BPS) invariants and the analysis of backreacted geometries. Detailed information about rigid supersymmetric theories in five dimensions is contained in an index counting refined BPS invariants. These BPS states fall into representations of SU(2){sub L} x SU(2){sub R}, the little group in five dimensions, which has an induced action on the cohomology of the moduli space of stable pairs. In the first part of this thesis, we present the computation of refined BPS state multiplicities associated to M-theory compactifications on local Calabi-Yau manifolds whose base is given by a del Pezzo or half K3 surface. For geometries with a toric realization we use an algorithm which is based on the Weierstrass normal form of the mirror geometry. In addition we use the refined holomorphic anomaly equation and the gap condition at the conifold locus in the moduli space in order to perform the direct integration and to fix the holomorphic ambiguity. In a second approach, we use the refined Goettsche formula and the refined modular anomaly equation that govern the (refined) genus expansion of the free energy of the half K3 surface. By this procedure, we compute the refined BPS invariants of the half K3 from which the results of the remaining del Pezzo surfaces are obtained by flop transitions and blow-downs. These calculations also make use of the high symmetry of the del Pezzo surfaces whose homology lattice contains the root lattice of exceptional Lie algebras. In cases where both approaches are applicable, we successfully check the compatibility of these two methods. In the second part of this thesis, we apply the results obtained from the calculation of the refined invariants of the del Pezzo respectively the half K3 surfaces to count non-perturbative objects in F-theory. The first application is given by BPS states of the E

  13. Reason for SU(6) grand unification

    International Nuclear Information System (INIS)

    Kim, J.E.

    1981-08-01

    An SU(6) model can naturally guarantee strong CP invariance. This also includes Georgi and Glashow's SU(5) model. The axion in this model can be either invisible or visible, depending on the symmetry breaking scheme. The invisible axion is identical to a Majoron. Also, there exists a relationship between 24sub(H) and 45sub(H) of SU(5). (author)

  14. Cosmological grand unification monopoles: astrophysical constraints

    International Nuclear Information System (INIS)

    Fry, J.N.

    1982-01-01

    I review the general arguments which suggest that relic GU magnetic monopoles should emerge from the early universe, and I discuss several astrophysical settings in which their effects could be, but are not, observed. This places limits on their possible flux, and their abundance bound to more ordinary material

  15. Focus point gauge mediation in product group unification

    International Nuclear Information System (INIS)

    Bruemmer, Felix; Ibe, Masahiro; Tokyo Univ., Kashiwa; Yanagida, Tsutomu T.

    2013-03-01

    In certain models of gauge-mediated supersymmetry breaking with messenger fields in incomplete GUT multiplets, the radiative corrections to the Higgs potential cancel out during renormalization group running. This allows for relatively heavy superpartners and for a 125 GeV Higgs while the ne-tuning remains modest. In this paper, we show that such gauge mediation models with ''focus point'' behaviour can be naturally embedded into a model of SU(5) x U(3) product group unification.

  16. Non-trivial frames for f(T) theories of gravity and beyond

    International Nuclear Information System (INIS)

    Ferraro, Rafael; Fiorini, Franco

    2011-01-01

    Some conceptual issues concerning f(T) theories - a family of modified gravity theories based on absolute parallelism - are analyzed. Due to the lack of local Lorentz invariance, the autoparallel frames satisfying the field equations are evasive to an a priori physical understanding. We exemplify this point by working out the vierbein (tetrad) fields for closed and open Friedmann-Robertson-Walker cosmologies.

  17. Non-trivial frames for f(T) theories of gravity and beyond

    Energy Technology Data Exchange (ETDEWEB)

    Ferraro, Rafael, E-mail: ferraro@iafe.uba.ar [Instituto de Astronomia y Fisica del Espacio, Casilla de Correo 67, Sucursal 28, 1428 Buenos Aires (Argentina); Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon I, 1428 Buenos Aires (Argentina); Fiorini, Franco, E-mail: franco@iafe.uba.ar [Instituto de Astronomia y Fisica del Espacio, Casilla de Correo 67, Sucursal 28, 1428 Buenos Aires (Argentina)

    2011-08-03

    Some conceptual issues concerning f(T) theories - a family of modified gravity theories based on absolute parallelism - are analyzed. Due to the lack of local Lorentz invariance, the autoparallel frames satisfying the field equations are evasive to an a priori physical understanding. We exemplify this point by working out the vierbein (tetrad) fields for closed and open Friedmann-Robertson-Walker cosmologies.

  18. On quantum corrected Kahler potentials in F-theory

    CERN Document Server

    García-Etxebarria, Iñaki; Savelli, Raffaele; Shiu, Gary

    2013-01-01

    We work out the exact in string coupling and perturbatively exact in \\alpha' result for the vector multiplet moduli K\\"ahler potential in a specific N=2 compactification of F-theory. The well-known correction cubic in {\\alpha}' is absent, but there is a rich structure of corrections at all even orders in \\alpha'. Moreover, each of these orders independently displays an SL(2,Z) invariant set of corrections in the string coupling. This generalizes earlier findings to the case of a non-trivial elliptic fibration. Our results pave the way for the analysis of quantum corrections in the more complicated N=1 context, and may have interesting implications for the study of moduli stabilization in string theory.

  19. Quantum effects from a purely geometrical relativity theory

    International Nuclear Information System (INIS)

    Ellis, Homer G

    2005-01-01

    A purely geometrical relativity theory results from a construction that produces from three-dimensional space a happy unification of Kaluza's five-dimensional theory and Weyl's conformal theory. The theory can provide geometrical explanations for the following observed phenomena, among others: (a) visibility lifetimes of elementary particles of lengths inversely proportional to their rest masses; (b) the equality of charge magnitude among all charged particles interacting at an event; (c) the propensity of electrons in atoms to be seen in discretely spaced orbits; and (d) 'quantum jumps' between those orbits. This suggests the possibility that the theory can provide a deterministic underpinning of quantum mechanics like that provided to thermodynamics by the molecular theory of gases

  20. Do Unification Models Explain the X-ray Properties of Radio Sources?

    NARCIS (Netherlands)

    Wilkes, Belinda J.; Kuraszkiewicz, J.; Haas, M.; Barthel, P.; Willner, S. P.; Leipski, C.; Worrall, D.; Birkinshaw, M.; Antonucci, R. R.; Ashby, M.; Chini, R.; Fazio, G. G.; Lawrence, C. R.; Ogle, P. M.; Schulz, B.

    Chandra observations of a complete, flux-limited sample of 38 high-redshift (1 Unification models and lead to estimates of the covering