Running coupling in SU(2) gauge theory with two adjoint fermions

DEFF Research Database (Denmark)

Rantaharju, Jarno; Rantalaiho, Teemu; Rummukainen, Kari

2016-01-01

We study SU(2) gauge theory with two Dirac fermions in the adjoint representation of the gauge group on the lattice. Using clover improved Wilson fermion action with hypercubic truncated stout smearing we perform simulations at larger coupling than before. We measure the evolution of the coupling...... with the existence of a fixed point in the interval 2.2g∗23. We also measure the anomalous dimension and find that its value at the fixed point is γ∗≃0.2±0.03....... constant using the step scaling method with the Schrödinger functional and study the remaining discretization effects. At weak coupling we observe significant discretization effects, which make it difficult to obtain a fully controlled continuum limit. Nevertheless, the data remains consistent...

A unified model of the strong and electroweak interactions based on the gauge group SU(18)L x SU(18)R

International Nuclear Information System (INIS)

Kim Il Kang

1986-01-01

On the basis of semi-simple gauge group G=SU(18) L x SU(18) R the unified theory of strong, weak and electromagnetic fields is constructed, and it is shown that the Weinberg angle and the energy of unification are in good agreement with the experimental values. (author)

Black holes with su(N) gauge field hair and superconducting horizons

Energy Technology Data Exchange (ETDEWEB)

Shepherd, Ben L.; Winstanley, Elizabeth [Consortium for Fundamental Physics, School of Mathematics and Statistics,The University of Sheffield,Hicks Building, Hounsfield Road, Sheffield S3 7RH (United Kingdom)

2017-01-16

We present new planar dyonic black hole solutions of the su(N) Einstein-Yang-Mills equations in asymptotically anti-de Sitter space-time, focussing on su(2) and su(3) gauge groups. The magnetic part of the gauge field forms a condensate close to the planar event horizon. We compare the free energy of a non-Abelian hairy black hole with that of an embedded Reissner-Nordström-anti-de Sitter (RN-AdS) black hole having the same Hawking temperature and electric charge. We find that the hairy black holes have lower free energy. We present evidence that there is a phase transition at a critical temperature, above which the only solutions are embedded RN-AdS black holes. At the critical temperature, an RN-AdS black hole can decay into a hairy black hole, and it is thermodynamically favourable to do so. Working in the probe limit, we compute the frequency-dependent conductivity, and find that enlarging the gauge group from su(2) to su(3) eliminates a divergence in the conductivity at nonzero frequency.

Black holes with su(N) gauge field hair and superconducting horizons

International Nuclear Information System (INIS)

Shepherd, Ben L.; Winstanley, Elizabeth

2017-01-01

We present new planar dyonic black hole solutions of the su(N) Einstein-Yang-Mills equations in asymptotically anti-de Sitter space-time, focussing on su(2) and su(3) gauge groups. The magnetic part of the gauge field forms a condensate close to the planar event horizon. We compare the free energy of a non-Abelian hairy black hole with that of an embedded Reissner-Nordström-anti-de Sitter (RN-AdS) black hole having the same Hawking temperature and electric charge. We find that the hairy black holes have lower free energy. We present evidence that there is a phase transition at a critical temperature, above which the only solutions are embedded RN-AdS black holes. At the critical temperature, an RN-AdS black hole can decay into a hairy black hole, and it is thermodynamically favourable to do so. Working in the probe limit, we compute the frequency-dependent conductivity, and find that enlarging the gauge group from su(2) to su(3) eliminates a divergence in the conductivity at nonzero frequency.

Vacuum structure of the SU(3) gauge field theory in the Coulomb gauge

International Nuclear Information System (INIS)

Yee, J.H.; Viswanathan, K.S.

1978-01-01

The SU(3) gauge field is studied in the Coulomb gauge. The Gribov ambiguities arising in the Coulomb gauge are analysed. Restricting to a class of spherically symmetric vacua it is shown that there exist non-trivial vacua characterized by a topological number eta=0, +-1/2, and +-2. This must be contrasted with the spherically symmetric SU(2) vacua which are characterized by eta=0, +-1/2. (Auth.)

Z2 monopoles in the standard SU(2) lattice gauge theory model

International Nuclear Information System (INIS)

Mack, G.; Petkova, V.B.

1979-04-01

The standard SU(2) lattice gauge theory model without fermions may be considered as a Z 2 model with monopoles and fluctuating coupling constants. At low temperatures β -1 (= small bare coupling constant) the monopoles are confined. (orig.) [de

Constant self-dual Abelian gauge fields and fermions in SU(2) gauge theory

International Nuclear Information System (INIS)

Kay, D.; Parthasarathy, R.; Viswanathan, K.S.

1983-01-01

Fermion one-loop corrections to the effective action in a self-dual Abelian background field are calculated for an SU(2) gauge theory. It is found that these corrections for massless fermions tend to destabilize the vacuum. The quantitative and qualitative features of such corrections for the case of massive fermions are discussed

UV completions of partial compositeness: the case for a SU(4) gauge group

International Nuclear Information System (INIS)

Ferretti, Gabriele

2014-01-01

We present a model of partial compositeness arising as the IR limit of a SU(4) gauge theory with only fermionic matter. This group is one of the most promising ones among a handful of possible choices allowing a symmetry breaking pattern incorporating custodial symmetry and a top partner candidate, while retaining asymptotic freedom. It is favored for not giving rise to lepto-quarks or Landau poles in the SM gauge couplings. The minimal UV theory consists of five hyperfermions in the anti-symmetric representation and three in the fundamental and anti-fundamental. The IR theory is centered around the coset SU(5)/SO(5), with top partners in the fundamental of SO(5), giving rise to one composite fermion of electric charge 5/3, three of charge 2/3 and one of charge −1/3. Electro-Weak symmetry breaking occurs via top-quark-driven vacuum misalignment. The top quark mass is generated via the mechanism of partial compositeness, while the remaining fermions acquire a mass via a standard quadratic coupling to the Higgs. We compute the top and bottom quark mass matrix and the Electro-Weak currents of the composite fermions. The model does not give rise to unacceptably large deviations from the SM Z→bb-bar decay width.

Critical behavior at the deconfinement phase phase transition of SU(2) lattice gauge theory in (2+1) dimensions

International Nuclear Information System (INIS)

Christensen, J.; Damgaard, P.H.

1991-01-01

The finite-temperature deconfinement phase transition of SU(2) lattice gauge theory in (2+1) dimensions is studied by Monte Carlo methods. Comparison is made with the expected form of correlation functions on both sides of the critical point. The critical behavior is compared with expectations based on universality arguments. Attempts are made to extract unbiased values of critical exponents on several lattices sizes. The behavior of Polyakov loops in higher representations of the gauge group is studied close to the phase transition. (orig.)

Thick vortices in SU(2) lattice gauge theory

OpenAIRE

Cheluvaraja, Srinath

2004-01-01

Three dimensional SU(2) lattice gauge theory is studied after eliminating thin monopoles and the smallest thick monopoles. Kinematically this constraint allows the formation of thick vortex loops which produce Z(2) fluctuations at longer length scales. The thick vortex loops are identified in a three dimensional simulation. A condensate of thick vortices persists even after the thin vortices have all disappeared. The thick vortices decouple at a slightly lower temperature (higher beta) than t...

Plaquette-plaquette correlations in the SU(2) lattice gauge theory

International Nuclear Information System (INIS)

Berg, B.

1980-09-01

Monte Carlo measurements of plaquette-plaquette correlations in the 4-dimensional SU(2) lattice gauge theory are reported. For low temperatures the glue ball mass (= inverse correlation length) is estimated to be msub(g) = (3.7 +- 1.2) √K, where K is the string tension. (orig.)

Effective monopole potential for SU(2) lattice gluodynamics in spatial maximal Abelian gauge

International Nuclear Information System (INIS)

Chernodub, M.N.; Polikarpov, M.I.; Veselov, A.I.

1999-01-01

We investigate the dual superconductor hypothesis in finite-temperature SU(2) lattice gluodynamics in the Spatial Maximal Abelian gauge. This gauge is more physical than the ordinary Maximal Abelian gauge due to absence of non-localities in temporal direction. We shown numerically that in the Spatial Maximal Abelian gauge the probability distribution of the abelian monopole field is consistent with the dual superconductor mechanism of confinement [ru

Variational estimates for the mass gap of SU(2) Euclidean lattice gauge theory

International Nuclear Information System (INIS)

Hari Dass, N.D.

1984-10-01

The purpose of this letter is to report on the progress made in our understanding of series expansions for the masses in lattice gauge theories by the application of variational techniques to the Euclidean SU(2) lattice gauge theory. (Auth.)

Projected Entangled Pair States with non-Abelian gauge symmetries: An SU(2) study

Energy Technology Data Exchange (ETDEWEB)

Zohar, Erez, E-mail: erez.zohar@mpq.mpg.de [Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße 1, 85748 Garching (Germany); Wahl, Thorsten B. [Rudolf Peierls Centre for Theoretical Physics, Oxford, 1 Keble Road, OX1 3NP (United Kingdom); Burrello, Michele, E-mail: michele.burrello@mpq.mpg.de [Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße 1, 85748 Garching (Germany); Cirac, J. Ignacio [Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße 1, 85748 Garching (Germany)

2016-11-15

Over the last years, Projected Entangled Pair States have demonstrated great power for the study of many body systems, as they naturally describe ground states of gapped many body Hamiltonians, and suggest a constructive way to encode and classify their symmetries. The PEPS study is not only limited to global symmetries, but has also been extended and applied for local symmetries, allowing to use them for the description of states in lattice gauge theories. In this paper we discuss PEPS with a local, SU(2) gauge symmetry, and demonstrate the use of PEPS features and techniques for the study of a simple family of many body states with a non-Abelian gauge symmetry. We present, in particular, the construction of fermionic PEPS able to describe both two-color fermionic matter and the degrees of freedom of an SU(2) gauge field with a suitable truncation.

Tadpole-improved SU(2) lattice gauge theory

Science.gov (United States)

Shakespeare, Norman H.; Trottier, Howard D.

1999-01-01

A comprehensive analysis of tadpole-improved SU(2) lattice gauge theory is made. Simulations are done on isotropic and anisotropic lattices, with and without improvement. Two tadpole renormalization schemes are employed, one using average plaquettes, the other using mean links in the Landau gauge. Simulations are done with spatial lattice spacings as in the range of about 0.1-0.4 fm. Results are presented for the static quark potential, the renormalized lattice anisotropy at/as (where at is the ``temporal'' lattice spacing), and for the scalar and tensor glueball masses. Tadpole improvement significantly reduces discretization errors in the static quark potential and in the scalar glueball mass, and results in very little renormalization of the bare anisotropy that is input to the action. We also find that tadpole improvement using mean links in the Landau gauge results in smaller discretization errors in the scalar glueball mass (as well as in the static quark potential), compared to when average plaquettes are used. The possibility is also raised that further improvement in the scalar glueball mass may result when the coefficients of the operators which correct for discretization errors in the action are computed beyond the tree level.

Analytic study of SU(3) lattice gauge theory

International Nuclear Information System (INIS)

Zheng Xite; Xu Yong

1989-01-01

The variational-cumulant expansion method has been extended to the case of lattice SU(3) Wilson model. The plaquette energy as an order paramenter has been calculated to the 2nd order expansion. No 1st order phase transition in the D = 4 case is found which is in agreement with the monte Carlo results, and the 1st order phase transition in the d = 5 case is clearly seen. The method can be used in the study of problems in LGT with SU(3) gauge group

Static forces in d=2+1 SU(N) gauge theories

International Nuclear Information System (INIS)

Meyer, H.B.

2006-07-01

Using a three-level algorithm we perform a high-precision lattice computation of the static force up to 1fm in the 2+1 dimensional SU(5) gauge theory. Discretization errors and the continuum limit are discussed in detail. By comparison with existing SU(2) and SU(3) data it is found that σr 2 0 =1.65-(π)/(24) holds at an accuracy of 1% for all N≥2, where r 0 is the Sommer reference scale. The effective central charge c(r) is obtained and an intermediate distance r s is defined via the property c(r s )=(π)/(24). It separates in a natural way the short-distance regime governed by perturbation theory from the long-distance regime described by an effective string theory. The ratio τ s /τ 0 decreases significantly from SU(2) to SU(3) to SU(5), where r s 0 . We give a preliminary estimate of its value in the large-N limit. The static force in the smallest representation of N-ality 2, which tends to the k=2 string tension as r→∞, is also computed up to 0.7 fm. The deviation from Casimir scaling is positive and grows from 0.1% to 1% in that range. (Orig.)

Dark revelations of the [SU(3)]3 and [SU(3)]4 gauge extensions of the standard model

Science.gov (United States)

Kownacki, Corey; Ma, Ernest; Pollard, Nicholas; Popov, Oleg; Zakeri, Mohammadreza

2018-02-01

Two theoretically well-motivated gauge extensions of the standard model are SU(3)C × SU(3)L × SU(3)R and SU(3)q × SU(3)L × SU(3)l × SU(3)R, where SU(3)q is the same as SU(3)C and SU(3)l is its color leptonic counterpart. Each has three variations, according to how SU(3)R is broken. It is shown here for the first time that a built-in dark U(1)D gauge symmetry exists in all six versions. However, the corresponding symmetry breaking pattern does not reduce properly to that of the standard model, unless an additional Z2‧ symmetry is defined, so that U(1)D ×Z2‧ is broken to Z2 dark parity. The available dark matter candidates in each case include fermions, scalars, as well as vector gauge bosons. This work points to the possible unity of matter with dark matter, the origin of which may not be ad hoc.

Dark revelations of the [SU(3]3 and [SU(3]4 gauge extensions of the standard model

Directory of Open Access Journals (Sweden)

Corey Kownacki

2018-02-01

Full Text Available Two theoretically well-motivated gauge extensions of the standard model are SU(3C×SU(3L×SU(3R and SU(3q×SU(3L×SU(3l×SU(3R, where SU(3q is the same as SU(3C and SU(3l is its color leptonic counterpart. Each has three variations, according to how SU(3R is broken. It is shown here for the first time that a built-in dark U(1D gauge symmetry exists in all six versions. However, the corresponding symmetry breaking pattern does not reduce properly to that of the standard model, unless an additional Z2′ symmetry is defined, so that U(1D×Z2′ is broken to Z2 dark parity. The available dark matter candidates in each case include fermions, scalars, as well as vector gauge bosons. This work points to the possible unity of matter with dark matter, the origin of which may not be ad hoc.

SU(2) Gauge Theory with Two Fundamental Flavours

DEFF Research Database (Denmark)

Arthur, Rudy; Drach, Vincent; Hansen, Martin

2016-01-01

We investigate the continuum spectrum of the SU(2) gauge theory with $N_f=2$ flavours of fermions in the fundamental representation. This model provides a minimal template which is ideal for a wide class of Standard Model extensions featuring novel strong dynamics that range from composite...... (Goldstone) Higgs theories to several intriguing types of dark matter candidates, such as the SIMPs. We improve our previous lattice analysis [1] by adding more data at light quark masses, at two additional lattice spacings, by determining the lattice cutoff via a Wilson flow measure of the $w_0$ parameter...

Departures from scaling in SU(2) lattice gauge theory

International Nuclear Information System (INIS)

Gutbrod, F.

1987-01-01

High statistics Monte Carlo Data in SU(2) lattice gauge theory are presented. At β = 2.6 and β = 2.7 large deviations form scaling are observed for Creutz ratios, when 12 4 and 24 4 lattice data are compared. There is a trend towards a restauration of asymptotic scaling with increasing β, which vanishes if at the higher value of β larger loops are considered than at lower β. The static qanti q-potential and an upper limit for the string tension are given. (orig.)

Improved thermodynamics of SU(2) gauge theory

Energy Technology Data Exchange (ETDEWEB)

Giudice, Pietro [University of Muenster, Institute for Theoretical Physics, Muenster (Germany); Piemonte, Stefano [University of Regensburg, Institute for Theoretical Physics, Regensburg (Germany)

2017-12-15

In this work we present the results of our investigation of the thermodynamics of SU(2) gauge theory. We employ a Symanzik improved action to reduce strongly the discretisations effects, and we use the scaling relations to take into account the finite volume effects close to the critical temperature. We determine the β-function for this particular theory and we use it in the determination of different thermodynamic observables. Finally we compare our results with previous work where only the standard Wilson action was considered. We confirm the relevance of using the improved action to access easily the correct continuum thermodynamics of the theory. (orig.)

Topological charge and cooling scales in pure SU(2) lattice gauge theory

OpenAIRE

Berg, Bernd A.; Clarke, David A.

2018-01-01

Using Monte Carlo simulations with overrelaxation, we have equilibrated lattices up to β=2.928, size 604, for pure SU(2) lattice gauge theory with the Wilson action. We calculate topological charges with the standard cooling method and find that they become more reliable with increasing β values and lattice sizes. Continuum limit estimates of the topological susceptibility χ are obtained of which we favor χ1/4/Tc=0.643(12), where Tc is the SU(2) deconfinement temperature. Differences between ...

Global aspects of gauge anomalies

International Nuclear Information System (INIS)

Zhang, H.

1988-01-01

This dissertation discusses the global aspects of gauge anomalies in even dimensions. After a very brief description of local gauge anomalies, the possible global gauge anomalies for various gauge theories are discussed using homotopy theory. One of the main results obtained in a general formula for the SU(n - k) global gauge anomaly coefficient in arbitrary 2n dimensions. The result is expressed in terms of the James number of the Stiefel manifold SU(n + 1)/SU(n - k) and the generalized Dynkin indices. From this, the possibilities of SU(n), SU(n - 1), and SU(2) global gauge anomalies in arbitrary 2n dimensions have been determined. We have also determined the possibilities of global gauge anomalies for the gauge groups SP(2N) and SO(N) in certain general dimensions, as well as for the exceptional gauge groups in specific dimensions. Moreover, several general propositions are formulated and proved which are very useful in the study of global gauge anomalies

Critical acceleration of finite temperature SU(2) gauge simulations

International Nuclear Information System (INIS)

Ben-Av, R.; Marcu, M.; Hamburg Univ.; Solomon, S.

1991-04-01

We present a cluster algorithm that strongly reduces critical slowing down for the SU(2) gauge theory on one time slice. The idea that underlies the new algorithm is to perform efficient flips for the signs of Polyakov loops. Ergodicity is ensured by combining it with a standard local algorithm. We show how to quantify critical slowing down for such a mixed algorithm. At the finite temperature transition, the dynamical critical exponent z is ≅0.5, whereas for the purely local algoirthm z ≅ 2. (orig.)

Center-vortex dominance after dimensional reduction of SU(2) lattice gauge theory

OpenAIRE

Gattnar, J.; Langfeld, K.; Schafke, A.; Reinhardt, H.

2000-01-01

The high-temperature phase of SU(2) Yang-Mills theory is addressed by means of dimensional reduction with a special emphasis on the properties of center vortices. For this purpose, the vortex vacuum which arises from center projection is studied in pure 3-dimensional Yang-Mills theory as well as in the 3-dimensional adjoint Higgs model which describes the high temperature phase of the 4-dimensional SU(2) gauge theory. We find center-dominance within the numerical accuracy of 10%.

Unitary gauge calculation of K0/sub L/ → μ+μ- in the Weinberg SU(2)'/sub L/ x U(1) gauge theory

International Nuclear Information System (INIS)

Olenick, R.P.

1979-01-01

The rare weak decay K 0 /sub L/ → μ + μ - is calculated in the unitary gauge of the Weinberg SU(2)/sub L/ x U(1) model of weak and electromagnetic interactions. A historical development of gauge theories is presented first; this indicates the need for extension of the hadron symmetry group to SU(4). The GIM mechanism, which extends this group by introducing the charmed quark, is incorporated into Weinberg theory. Explicit calculations of the fourth-order Feynman diagrams representing W + W - , Z 0 , γ, and Higgs scalar intermediate states are performed. Through the technique of dimensional regularization the divergent amplitudes are evaluated, and the calculation is shown to be renormalizable by counterterms generated from the original Lagrangian. The Higgs scalar contribution to the effective Lagrangian is found to be greatly suppressed compared to the W + W - and Z 0 contributions, which are used to estimate the charmed quark mass. Analysis reveals that a charmed quark mass less than or equal to 5 GeV will suppress the decay rate to the experimentally observed value. Concluding remarks are made

Ground-state projection multigrid for propagators in 4-dimensional SU(2) gauge fields

International Nuclear Information System (INIS)

Kalkreuter, T.

1991-09-01

The ground-state projection multigrid method is studied for computations of slowly decaying bosonic propagators in 4-dimensional SU(2) lattice gauge theory. The defining eigenvalue equation for the restriction operator is solved exactly. Although the critical exponent z is not reduced in nontrivial gauge fields, multigrid still yields considerable speedup compared with conventional relaxation. Multigrid is also able to outperform the conjugate gradient algorithm. (orig.)

A separate SU(2) for the third family: Topflavor

International Nuclear Information System (INIS)

Muller, D.J.; Nandi, S.; Univ. of Texas, Austin, TX

1996-01-01

The authors consider the extended electroweak gauge group SU(2) 1 xSU(2) x xU(1) Y where the first and second families of fermions couple to SU(2) 1 while the third family couples to SU(2) 2 . Bounds based on precision electroweak observables and heavy gauge boson searches are placed on the new parameters of the theory. The extra gauge bosons can be as light as about a TeV and can be discovered at future colliders such as the NLC and LHC for a wide range of the parameter space. FCNC interactions are also considered

Universality in the mixed SU(2) lattice gauge theory. Nonperturbative approach to the ratio of Λ parameters

International Nuclear Information System (INIS)

Makeenko, Yu.M.; Polikarpov, M.I.; Zhelonkin, A.V.

1983-01-01

The mixed SU(2) lattice gauge theory (LGT) is approximately represented as an effective SU(2) LGT with Wilson's action. This approach is applied to the nonperturbative calculation of the ratio of Λ-parameters in the mixed SU(2) LGT. It is shown that the formulas obtained fairly describe the Monte Carlo data so that universality holds in the mixed SU(2) LGT

On the phase structure of lattice SU(2) Gauge-Higgs theory

International Nuclear Information System (INIS)

Gerdt, V.P.; Mitryushkin, V.K.; Zadorozhnyj, A.M.; Ilchev, A.S.

1985-01-01

The results on the phase structure of SU(2) gauge theory coupled with radially active Higgs fields are iscussed. It is shown that obtained results are not in contradiction with the known ones. The first order phase transitions observed are confirmed by the Monte Carlo calcUlations and by the analysis of an approximate effective potential

Center vortex properties in the Laplace center gauge of SU(2) Yang-Mills theory

OpenAIRE

Langfeld, K.; Reinhardt, H.; Schafke, A.

2001-01-01

Resorting to the the Laplace center gauge (LCG) and to the Maximal-center gauge (MCG), respectively, confining vortices are defined by center projection in either case. Vortex properties are investigated in the continuum limit of SU(2) lattice gauge theory. The vortex (area) density and the density of vortex crossing points are investigated. In the case of MCG, both densities are physical quantities in the continuum limit. By contrast, in the LCG the piercing as well as the crossing points li...

A finite size scaling test of an SU(2) gauge-spin system

International Nuclear Information System (INIS)

Tomiya, M.; Hattori, T.

1984-01-01

We calculate the correlation functions in the SU(2) gauge-spin system with spins in the fundamental representation. We analyze the result making use of finite size scaling. There is a possibility that there are no second order phase transition lines in this model, contrary to previous assertions. (orig.)

Lattice gauge theory

International Nuclear Information System (INIS)

Mack, G.

1982-01-01

After a description of a pure Yang-Mills theory on a lattice, the author considers a three-dimensional pure U(1) lattice gauge theory. Thereafter he discusses the exact relation between lattice gauge theories with the gauge groups SU(2) and SO(3). Finally he presents Monte Carlo data on phase transitions in SU(2) and SO(3) lattice gauge models. (HSI)

On the presence of lower dimensional confinement mechanisms in 4d SU2 lattice gauge theory

International Nuclear Information System (INIS)

Hari Dass, N.D.

1983-11-01

The presence of an essentially two-dimensional confinement mechanism in 4d SU 2 gauge theory has been conjectured. The authors present an explicit realization of this conjecture valid up to β = 1.8 based on variational investigations of lattice gauge theories. (Auth.)

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)

Closed flux tubes in D=2+1SU(N) gauge theories: dynamics and effective string description

Energy Technology Data Exchange (ETDEWEB)

Athenodorou, Andreas [Department of Physics, University of Cyprus,POB 20537, 1678 Nicosia (Cyprus); Computation-based Science and Technology Research Center, The Cyprus Institute,20 Kavafi Str., Nicosia 2121 (Cyprus); Teper, Michael [Rudolf Peierls Centre for Theoretical Physics, University of Oxford,1 Keble Road, Oxford OX1 3NP (United Kingdom)

2016-10-18

We extend our earlier calculations of the spectrum of closed flux tubes in SU(N) gauge theories in 2+1 dimensions, with a focus on questions raised by recent theoretical progress on the effective string action of long flux tubes and the world-sheet action for flux tubes of moderate lengths. Our new calculations in SU(4) and SU(8) provide evidence that the leading O(1/l{sup γ}) non-universal correction to the flux tube ground state energy does indeed have a power γ≥7. We perform a study in SU(2), where we can traverse the length at which the Nambu-Goto ground state becomes tachyonic, to obtain an all-N view of the spectrum. Our comparison of the k=2 flux tube excitation energies in SU(4) and SU(6) suggests that the massive world sheet excitation associated with the k=2 binding has a scale that knows about the group and hence the theory in the bulk, and we comment on the potential implications of world sheet massive modes for the bulk spectrum. We provide a quantitative analysis of the surprising (near-)orthogonality of flux tubes carrying flux in different SU(N) representations, which implies that their screening by gluons is highly suppressed even at small N.

Closed flux tubes in D=2+1SU(N) gauge theories: dynamics and effective string description

International Nuclear Information System (INIS)

Athenodorou, Andreas; Teper, Michael

2016-01-01

We extend our earlier calculations of the spectrum of closed flux tubes in SU(N) gauge theories in 2+1 dimensions, with a focus on questions raised by recent theoretical progress on the effective string action of long flux tubes and the world-sheet action for flux tubes of moderate lengths. Our new calculations in SU(4) and SU(8) provide evidence that the leading O(1/l"γ) non-universal correction to the flux tube ground state energy does indeed have a power γ≥7. We perform a study in SU(2), where we can traverse the length at which the Nambu-Goto ground state becomes tachyonic, to obtain an all-N view of the spectrum. Our comparison of the k=2 flux tube excitation energies in SU(4) and SU(6) suggests that the massive world sheet excitation associated with the k=2 binding has a scale that knows about the group and hence the theory in the bulk, and we comment on the potential implications of world sheet massive modes for the bulk spectrum. We provide a quantitative analysis of the surprising (near-)orthogonality of flux tubes carrying flux in different SU(N) representations, which implies that their screening by gluons is highly suppressed even at small N.

Response of SU(2) lattice gauge theory to a gauge invariant external field

International Nuclear Information System (INIS)

Goepfert, M.

1980-10-01

Topologically determined Z(2) variables in pure SU(2) lattice gauge theory are discussed. They count the number of 'vortex souls'. The expectation value of the corresponding Z(2) loop and the dependence of the string tension on an external field h coupled to them is calculated to lowest order in the high temperature expansion. The result is in agreement with the conjecture that the probability distribution of vortex souls determines the string tension. A different formula for the string tension is found in the two limiting cases 0 < /h/ << β << 1 and 0 < β << h << 1. This penomenon is traced to the effect of short range interactions of the vortex souls which are mediated by the other excitations in the theory. (orig.)

Vacuum expectation values of Higgs scalars in a SU(2)/sub L/ x SU(2)/sub R/ x U(1) gauge model

International Nuclear Information System (INIS)

Kitazoe, T.; Mainland, G.B.; Tanaka, K.

1979-01-01

We determine the vacuum expectation values of the Higgs scalars within the framework of a six-quark SU(2)/sub L/ x SU(2)/sub R/ x U(1) gauge model after the imposition of discrete symmetries that are necessary in order to express the Cabibbo angle in terms of quark mass ratios and phases of the vacuum expectation values. We find both real and complex solutions for the vacuum expectation values depending on the relative values of the parameters in the Higgs potential

Vacuum expectation values of Higgs scalars in a SU(2)/sub L/ X SU(2)/sub R/ X U(1) gauge model

International Nuclear Information System (INIS)

Kitazoe, T.; Mainland, G.B.; Tanaka, K.

1978-01-01

The vacuum expectation values of the Higgs scalars are determined within the framework of a six quark SU(2)/sub L/ x SU(2)/sub R/ x U(1) gauge model after the imposition of discrete symmetrics that are necessary in order to express the Cabibbo angle in terms of quark mass ratios and phases of the vacuum expectation values. Both real and complex solutions are found for the vacuum expectation values depending on the relative values of the parameters in the Higgs potential

Chiral anomalies and constraints on the gauge group in higher-dimensional supersymmetric Yang-Mills theories

International Nuclear Information System (INIS)

Townsend, P.K.; Sierra, G.

1983-01-01

Chiral anomalies for gauge theories in any even dimension are computed and the results applied to supersymmetric theories in D=6, 8 and 10. For D=8 there is an anomalous chiral U(1) invariance, just as in D=4, except for certain special groups. For D=6 and D=10 there is no anomalous chiral U(1) symmetry, but the gauge current is anomalous except for certain ''anomaly-free'' groups. For D=6 the group is thereby constrained to be one of [SU(2), SU(3), exceptional], while for D=10 it is constrained to be one of [SU(n)n 8 ]. (orig.)

Confinement in F4 Exceptional Gauge Group Using Domain Structures

Science.gov (United States)

Rafibakhsh, Shahnoosh; Shahlaei, Amir

2017-03-01

We calculate the potential between static quarks in the fundamental representation of the F4 exceptional gauge group using domain structures of the thick center vortex model. As non-trivial center elements are absent, the asymptotic string tension is lost while an intermediate linear potential is observed. SU(2) is a subgroup of F4. Investigating the decomposition of the 26 dimensional representation of F4 to the SU(2) representations, might explain what accounts for the intermediate linear potential, in the exceptional groups with no center element.

Dynamical Symmetry Breaking of Extended Gauge Symmetries

OpenAIRE

Appelquist, Thomas; Shrock, Robert

2003-01-01

We construct asymptotically free gauge theories exhibiting dynamical breaking of the left-right, strong-electroweak gauge group $G_{LR} = {\\rm SU}(3)_c \\times {\\rm SU}(2)_L \\times {\\rm SU}(2)_R \\times {\\rm U}(1)_{B-L}$, and its extension to the Pati-Salam gauge group $G_{422}={\\rm SU}(4)_{PS} \\times {\\rm SU}(2)_L \\times {\\rm SU}(2)_R$. The models incorporate technicolor for electroweak breaking, and extended technicolor for the breaking of $G_{LR}$ and $G_{422}$ and the generation of fermion ...

Global gauge anomaly of classical groups in even dimension

International Nuclear Information System (INIS)

Okubo, S.; Zhang, H.

1989-01-01

Explicit expression of global gauge anomaly coefficients A(ω) of locally anomaly-free representation ωof classical groups SU(N), Sp(2N) and SO(N) have been calculated in even dimensional space-time by uses of group theory and homotopy theory. As a by-product, the authors prove some modular relations involving the n-th Dynkin indices Q n ω of these groups

Scattering lengths in SU(2) gauge theory with two fundamental fermions

DEFF Research Database (Denmark)

Arthur, R.; Drach, V.; Hansen, Martin Rasmus Lundquist

2014-01-01

We investigate non perturbatively scattering properties of Goldstone Bosons in an SU(2) gauge theory with two Wilson fermions in the fundamental representation. Such a theory can be used to build extensions of the Standard Model that unifies Technicolor and pseudo Goldstone composite Higgs models...... the expected chiral symmetry breaking pattern. We then discuss how to compute them on the lattice and give preliminary results using finite size methods....

On the topological structure of the vacuum in SU(2) and SU(3) lattice gauge theories

International Nuclear Information System (INIS)

Ishikawa, K.; Schierholz, G.; Schneider, H.; Teper, M.

1983-01-01

We present Monte Carlo measurements of the net topological charge of the vacuum in SU(2) and SU(3) lattice gauge theories. In both cases there is no evidence of any topological structure, and the values obtained are a factor of 0(100) smaller than expectations based on analyses of the U(1) problem. Moreover we find a strong sensitivity to the lattice size and to the boundary conditions imposed on the lattice. We comment on the physical significance of these results, establish criteria for the reliable performance of such calculations, and remark on the possibly detrimental impact of these findings on the calculation of hadron spectra

Topology in SU(2) lattice gauge theory and parallelization of functional magnetic resonance imaging

Energy Technology Data Exchange (ETDEWEB)

Solbrig, Stefan

2008-07-01

In this thesis, I discuss topological properties of quenched SU(2) lattice gauge fields. In particular, clusters of topological charge density exhibit a power-law. The exponent of that power-law can be used to validate models for lattice gauge fields. Instead of working with fixed cutoffs of the topological charge density, using the notion of a ''watermark'' is more convenient. Furthermore, I discuss how a parallel computer, originally designed for lattice gauge field simulations, can be used for functional magnetic resonance imaging. Multi parameter fits can be parallelized to achieve almost real-time evaluation of fMRI data. (orig.)

Topology in SU(2) lattice gauge theory and parallelization of functional magnetic resonance imaging

International Nuclear Information System (INIS)

Solbrig, Stefan

2008-01-01

In this thesis, I discuss topological properties of quenched SU(2) lattice gauge fields. In particular, clusters of topological charge density exhibit a power-law. The exponent of that power-law can be used to validate models for lattice gauge fields. Instead of working with fixed cutoffs of the topological charge density, using the notion of a ''watermark'' is more convenient. Furthermore, I discuss how a parallel computer, originally designed for lattice gauge field simulations, can be used for functional magnetic resonance imaging. Multi parameter fits can be parallelized to achieve almost real-time evaluation of fMRI data. (orig.)

Optimization of renormalization group transformations in lattice gauge theory

International Nuclear Information System (INIS)

Lang, C.B.; Salmhofer, M.

1988-01-01

We discuss the dependence of the renormalization group flow on the choice of the renormalization group transformation (RGT). An optimal choice of the transformation's parameters should lead to a renormalized trajectory close to a few-parameter action. We apply a recently developed method to determine an optimal RGT to SU(2) lattice gauge theory and discuss the achieved improvement. (orig.)

Spontaneous compactification of D=10 Maxwell-Einstein theory leads to SU(3) X SU(2) X U(1) gauge symmetry

International Nuclear Information System (INIS)

Watamura, S.

1983-01-01

Solutions of ten-dimensional Maxwell-Einstein theory and a bosonic part of N = 2, D = 10 supergravity theory are examined. It is shown that there is a solution for which six-dimensional internal space is compactified into CP 2 x S 2 . The gauge symmetry of the effective four-dimensional theory is SU(3) x SU(2) x U(1). The introduction of fermions is also considered. The requirement of consistency in introducing a spinsup(C) structure on CP 2 results in a U(1) charge quantization condition. (orig.)

Inflation and monopoles in supersymmetric SU(4)c x SU(2)L x SU(2)R

International Nuclear Information System (INIS)

Jeannerot, R.; Khalil, S.; Lazarides, G.; Shafi, Q.

2000-02-01

We show how hybrid inflation can be successfully realized in a supersymmetric model with gauge group G PS = SU(4) c x SU(2) L x SU(2) R . By including a non-renormalizable superpotential term, we generate an inflationary valley along which G PS is broken to the standard model gauge group. Thus, catastrophic production of the doubly charged magnetic monopoles, which are predicted by the model, cannot occur at the end of inflation. The results of the cosmic background explorer can be reproduced with natural values (of order 10 -3 ) of the relevant coupling constant, and symmetry breaking scale of G PS close to 10 16 GeV. The spectral index of density perturbations lies between unity and 0.94. Moreover, the μ-term is generated via a Peccei-Quinn symmetry and proton is practically stable. Baryogenesis in the universe takes place via leptogenesis. The low deuterium abundance constraint on the baryon asymmetry, the gravitino limit on the reheat temperature and the requirement of almost maximal ν μ - ν τ mixing from SuperKamiokande can be simultaneously met with m νμ , m ντ and heaviest Dirac neutrino mass determined from the large angle MSW resolution of the solar neutrino problem, the SuperKamiokande results and SU(4) c symmetry respectively. (author)

New gauged N = 8, D = 4 supergravities

International Nuclear Information System (INIS)

Hull, C M

2003-01-01

New gaugings of four-dimensional N = 8 supergravity are constructed, including one which has a Minkowski space vacuum that preserves N = 2 supersymmetry and in which the gauge group is broken to SU(3) x U(1) 2 . Previous gaugings used the form of the ungauged action which is invariant under a rigid SL (8,R) symmetry and promoted a 28-dimensional subgroup (SO(8), SO(p, 8 - p) or the non-semi-simple contraction CSO(p, q, 8 - p - q)) to a local gauge group. Here, a dual form of the ungauged action is used which is invariant under SU*(8) instead of SL (8,R) and new theories are obtained by gauging 28-dimensional subgroups of SU*(8). The gauge groups are non-semi-simple and are different real forms of the CSO(2p, 8 - 2p) groups, denoted as CSO*(2p, 8 - 2p), and the new theories have a rigid SU(2) symmetry. The five-dimensional gauged N = 8 supergravities are dimensionally reduced to D = 4. The D = 5, SO(p, 6 - p) gauge theories reduce, after a duality transformation, to the D = 4, CSO(p, 6 - p, 2) gauging while the SO*(6) gauge theory reduces to the D = 4, CSO*(6, 2) gauge theory. The new theories are related to the old ones via an analytic continuation. The non-semi-simple gaugings can be dualized to forms with different gauge groups

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.

Topology in SU(2) lattice gauge theory and parallelization of functional magnetic resonance imaging

Energy Technology Data Exchange (ETDEWEB)

Solbrig, Stefan

2008-07-01

In this thesis, I discuss topological properties of quenched SU(2) lattice gauge fields. In particular, clusters of topological charge density exhibit a power-law. The exponent of that power-law can be used to validate models for lattice gauge fields. Instead of working with fixed cutoffs of the topological charge density, using the notion of a ''watermark'' is more convenient. Furthermore, I discuss how a parallel computer, originally designed for lattice gauge field simulations, can be used for functional magnetic resonance imaging. Multi parameter fits can be parallelized to achieve almost real-time evaluation of fMRI data. (orig.)

Classical local SU(3 gauge invariance in Weyl 2-spinor language and quark–gluon plasma equations of motion

Directory of Open Access Journals (Sweden)

J. Buitrago

Full Text Available In a new classical Weyl 2-spinor approach to non abelian gauge theories, starting with the U(1 gauge group in a previous work, we study now the SU(3 case corresponding to quarks (antiquarks interacting with color fields. The principal difference with the conventional approach is that particle-field interactions are not described by means of potentials but by the field strength magnitudes. Some analytical expressions showing similarities with electrodynamics are obtained. Classical equations that describe the behavior of quarks under gluon fields might be in principle applied to the quark–gluon plasma phase existing during the first instants of the Universe.

Focus point gauge mediation in product group unification

Energy Technology Data Exchange (ETDEWEB)

Bruemmer, Felix [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Ibe, Masahiro [Tokyo Univ., Kashiwa (Japan). Kavli IPMU, TODIAS; Tokyo Univ., Kashiwa (Japan). ICRR; Yanagida, Tsutomu T. [Tokyo Univ., Kashiwa (Japan). Kavli IPMU, TODIAS

2013-03-15

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.

Independent SU(2)-loop variables

International Nuclear Information System (INIS)

Loll, R.

1991-04-01

We give a reduction procedure for SU(2)-trace variables and introduce a complete set of indepentent, gauge-invariant and almost local loop variables for the configuration space of SU(2)-lattice gauge theory in 2+1 dimensions. (orig.)

T expansion and SU(2) lattice gauge theory

International Nuclear Information System (INIS)

Horn, D.; Karliner, M.; Weinstein, M.

1985-01-01

This paper presents the results obtained by applying the t expansion to the case of an SU(2) lattice gauge theory in 3+1 space-time dimensions. We compute the vacuum energy density, specific heat, string tension sigma, mass M of the lowest-lying 0 ++ glueball, and the ratio R = M 2 /sigma. Our computations converge best for the energy density, specific heat, and R, and these quantities exhibit behavior which agrees with what we expect on general grounds and what is known from Euclidean Monte Carlo calculations. In particular we see a broad lump in the specific heat and determine √R to be √R = 3.5 +- 0.2, a value which lies in the ballpark of values obtained from Monte Carlo calculations. Our direct computations of the mass of the 0 ++ glueball and string tension cannot be easily compared to the results of Monte Carlo calculations, but appear to be consistent with what one would expect

SU(N) chiral gauge theories on the lattice

International Nuclear Information System (INIS)

Golterman, Maarten; Shamir, Yigal

2004-01-01

We extend the construction of lattice chiral gauge theories based on non-perturbative gauge fixing to the non-Abelian case. A key ingredient is that fermion doublers can be avoided at a novel type of critical point which is only accessible through gauge fixing, as we have shown before in the Abelian case. The new ingredient allowing us to deal with the non-Abelian case as well is the use of equivariant gauge fixing, which handles Gribov copies correctly, and avoids Neuberger's no-go theorem. We use this method in order to gauge fix the non-Abelian group (which we will take to be SU(N)) down to its maximal Abelian subgroup. Obtaining an undoubled, chiral fermion content requires us to gauge-fix also the remaining Abelian gauge symmetry. This modifies the equivariant Becchi-Rouet-Stora-Tyutin (BRST) identities, but their use in proving unitarity remains intact, as we show in perturbation theory. On the lattice, equivariant BRST symmetry as well as the Abelian gauge invariance are broken, and a judiciously chosen irrelevant term must be added to the lattice gauge-fixing action in order to have access to the desired critical point in the phase diagram. We argue that gauge invariance is restored in the continuum limit by adjusting a finite number of counter terms. We emphasize that weak-coupling perturbation theory applies at the critical point which defines the continuum limit of our lattice chiral gauge theory

Gauge field models

International Nuclear Information System (INIS)

Becchi, C.; Rouet, A.; Stora, R.

1975-10-01

Stora's analysis is continued in discussing the nonabelian (Yang-Mills) gauge field models (G.F.M.). The gauge independence of the physical scattering operator is discussed in some details and the connection between its unitary and the Slavnov symmetry outlined. Only the models involving semisimple gauge groups are considered. This greatly simplifies the analysis of the possible quantum corrections to the Quantum Action Principle which is reduced to the study of the cohomology group of the Lie algebra characterizing the gauge theory. The discussion is at the classical level for the algebraic properties of the SU(2) Higgs-Kibble-Englert-Brout-Faddeev-Popov lagrangian and its invariance under Slavnov identity transformations is exhibited. The renormalization of the Slavnov identity in the G.M.F. involving semisimple gauge groups is studied. The unitary and gauge independence of the physical S operator in the SU(2) H.K. model is dealt with [fr

Observing long colour flux tubes in SU(2) lattice gauge theory

CERN Document Server

Bali, G S; Schlichter, C; Bali, G S; Schilling, K; Schlichter, C

1995-01-01

We present results of a high statistics study of the chromo field distribution between static quarks in SU(2) gauge theory on lattices of volumes 16^4, 32^4, and 48^3*64, with physical extent ranging from 1.3 fm up to 2.7 fm at beta=2.5, beta=2.635, and beta=2.74. We establish string formation over physical distances as large as 2 fm. The results are tested against Michael's sum rules. A detailed investigation of the transverse action and energy flux tube profiles is provided. As a by-product, we obtain the static lattice potential in unpreceded accuracy.

Phase transitions and flux distributions of SU(2) lattice gauge theory

International Nuclear Information System (INIS)

Peng, Yingcai.

1993-01-01

The strong interactions between quarks are believed to be described by Quantum Chromodynamics (QCD), which is a non-abelian SU(3) gauge theory. It is known that QCD undergoes a deconfining phase transition at very high temperatures, that is, at low temperatures QCD is in confined phase, at sufficient high temperatures it is in an unconfined phase. Also, quark confinement is believed to be due to string formation. In this dissertation the authors studied SU(2) gauge theory using numerical methods of LGT, which will provide some insights about the properties of QCD because SU(2) is similar to SU(3). They measured the flux distributions of a q bar q pair at various temperatures in different volumes. They find that in the limit of infinite volumes the flux distribution is different in the two phases. In the confined phase strong evidence is found for the string formation, however, in the unconfined phase there is no string formation. On the other hand, in the limit of zero temperature and finite volumes they find a clear signal for string formation in the large volume region, however, the string tension measured in intermediate volumes is due to finite volume effects, there is no intrinsic string formation. The color flux energies (action) of the q bar q pair are described by Michael sum rules. The original Michael sum rules deal with a static q bar q pair at zero temperature in infinite volumes. To check these sum rules with flux data at finite temperatures, they present a complete derivation for the sum rules, thus generalizing them to account for finite temperature effects. They find that the flux data are consistent with the prediction of generalized sum rules. The study elucidates the rich structures of QCD, and provides evidence for quark confinement and string formation. This supports the belief that QCD is a correct theory for strong interactions, and quark confinement can be explained by QCD

SU (2) lattice gauge theory simulations on Fermi GPUs

International Nuclear Information System (INIS)

Cardoso, Nuno; Bicudo, Pedro

2011-01-01

In this work we explore the performance of CUDA in quenched lattice SU (2) simulations. CUDA, NVIDIA Compute Unified Device Architecture, is a hardware and software architecture developed by NVIDIA for computing on the GPU. We present an analysis and performance comparison between the GPU and CPU in single and double precision. Analyses with multiple GPUs and two different architectures (G200 and Fermi architectures) are also presented. In order to obtain a high performance, the code must be optimized for the GPU architecture, i.e., an implementation that exploits the memory hierarchy of the CUDA programming model. We produce codes for the Monte Carlo generation of SU (2) lattice gauge configurations, for the mean plaquette, for the Polyakov Loop at finite T and for the Wilson loop. We also present results for the potential using many configurations (50,000) without smearing and almost 2000 configurations with APE smearing. With two Fermi GPUs we have achieved an excellent performance of 200x the speed over one CPU, in single precision, around 110 Gflops/s. We also find that, using the Fermi architecture, double precision computations for the static quark-antiquark potential are not much slower (less than 2x slower) than single precision computations.

Supersymmetric gauge theories with classical groups via M theory fivebrane

International Nuclear Information System (INIS)

Terashima, S.

1998-01-01

We study the moduli space of vacua of four-dimensional N=1 and N=2 supersymmetric gauge theories with the gauge groups Sp(2N c ), SO(2N c ) and SO(2N c +1) using the M theory fivebrane. Higgs branches of the N=2 supersymmetric gauge theories are interpreted in terms of the M theory fivebrane and the type IIA s-rule is realized in it. In particular, we construct the fivebrane configuration which corresponds to a special Higgs branch root. This root is analogous to the baryonic branch root in the SU(N c ) theory which remains as a vacuum after the adjoint mass perturbation to break N=2 to N=1. Furthermore, we obtain the monopole condensations and the meson vacuum expectation values in the confining phase of N=1 supersymmetric gauge theories using the fivebrane technique. These are in complete agreement with the field theory results for the vacua in the phase with a single confined photon. (orig.)

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.

Gauge invariance and fermion mass dimensions

International Nuclear Information System (INIS)

Elias, V.

1979-05-01

Renormalization-group equation fermion mass dimensions are shown to be gauge dependent in gauge theories possessing non-vector couplings of gauge bosons to fermions. However, the ratios of running fermion masses are explicitly shown to be gauge invariant in the SU(5) and SU(2) x U(1) examples of such theories. (author)

Spin transistor action from Onsager reciprocity and SU(2) gauge theory

Energy Technology Data Exchange (ETDEWEB)

Adagideli, Inanc [Faculty of Engineering and Natural Sciences, Sabanci University, Istanbul (Turkey); Lutsker, Vitalij; Scheid, Matthias; Richter, Klaus [Institut fuer Theoretische Physik, Universitaet Regensburg, 93040 Regensburg (Germany); Jacquod, Philippe [Physics Department, University of Arizona, Tucson, AZ (United States)

2012-07-01

We construct a local gauge transformation to show how, in confined systems, a generic, weak non-homogeneous SU(2) spin-orbit Hamiltonian reduces to two U(1) Hamiltonians for spinless fermions at opposite magnetic fields, to leading order in the spin-orbit strength. Using an Onsager relation, we further show how the resulting spin conductance vanishes in a two-terminal setup, and how it is turned on by either weakly breaking time-reversal symmetry or opening additional transport terminals. We numerically check our theory for mesoscopic cavities as well as Aharonov-Bohm rings.

Condensates near the Argyres-Douglas point in SU (2) gauge theory with broken Ν = 2 supersymmetry

International Nuclear Information System (INIS)

Gorsky, A.

2002-01-01

The behaviour of the chiral condensates in the SU(2) gauge theory with broken N = 2 supersymmetry is reviewed. The calculation of monopole, dyon, and charge condensates is described. It is shown that the monopole and charge condensates vanish at the Argyres-Douglas point where the monopole and charge vacua collide. This phenomenon is interpreted as a deconfinement of electric and magnetic charges at the Argyres-Douglas point. (authors)

Neutral currents and the gauge group of weak and electromagnetic interactions

International Nuclear Information System (INIS)

Rajpoot, S.

1977-12-01

In considering the question of neutral current parity conversation, models of weak and electromagnetic interactions based on the gauge sub group SU(2)sub(L)xSU(2)sub(R)x(U) 1 are examined. The thesis is presented in the following sections: (1) Introduction. (2) Natural left-right symmetric theory and its neutral current phenomenology. (3) Effects of neutral weak currents in electron-positron annihilation. (4) Dilepton production in pp and anti pp collisions as a probe to the nature of the neutral current interaction. (U.K.)

Phenomenology of an SU(2)×SU(2)×U(1) model with lepton-flavour non-universality

Energy Technology Data Exchange (ETDEWEB)

Boucenna, Sofiane M. [Laboratori Nazionali di Frascati, INFN,Via Enrico Fermi 40, 100044 Frascati (Italy); Celis, Alejandro [Arnold Sommerfeld Center for Theoretical Physics, Fakultät für Physik,Ludwig-Maximilians-Universität München,Theresienstrasse 37, 80333 München (Germany); Fuentes-Martín, Javier; Vicente, Avelino [Instituto de Física Corpuscular, Universitat de València - CSIC,E-46071 València (Spain); Virto, Javier [Albert Einstein Center for Fundamental Physics,Institute for Theoretical Physics, University of Bern,CH-3012 Bern (Switzerland)

2016-12-14

We investigate a gauge extension of the Standard Model in light of the observed hints of lepton universality violation in b→cℓν and b→sℓ{sup +}ℓ{sup −} decays at BaBar, Belle and LHCb. The model consists of an extended gauge group SU(2){sub 1}×SU(2){sub 2}×U(1){sub Y} which breaks spontaneously around the TeV scale to the electroweak gauge group. Fermion mixing effects with vector-like fermions give rise to potentially large new physics contributions in flavour transitions mediated by W{sup ′} and Z{sup ′} bosons. This model can ease tensions in B-physics data while satisfying stringent bounds from flavour physics, and electroweak precision data. Possible ways to test the proposed new physics scenario with upcoming experimental measurements are discussed. Among other predictions, the ratios R{sub M}=Γ(B→Mμ{sup +}μ{sup −})/Γ(B→Me{sup +}e{sup −}), with M=K{sup ∗},ϕ, are found to be reduced with respect to the Standard Model expectation R{sub M}≃1.

The string tension and the scaling behavior of SU(2) gauge theory on a random lattice

International Nuclear Information System (INIS)

Qui Zhaoming; Ren Haichang; Academia Sinica, Beijing; Wang Xiaoqun; Yang Zhixing; Zhao Enping

1987-01-01

The SU(2) gauge theory on an 8 4 random lattice has been studied by the Monte Carlo method. The string tensions have been evaluated. They display the expected scaling behavior for β = 1.2-1.3. The scale parameter Λ RAN has been determined approximately. (orig.)

SU(4) x U(1) gauge theory. II. CP nonconservation

International Nuclear Information System (INIS)

Deshpande, N.G.; Hwa, R.C.; Mannheim, P.D.

1979-01-01

We exploit the higher symmetry inherent in an SU(4) x U(1) gauge theory to construct a spontaneously broken theory of CP nonconservation. Higgs multiplets in the adjoint representation of SU(4) contain both even and odd CP fields; thus, requiring the simultaneous nonvanishing of the vacuum expectation values of these fields leads to CP noninvariance of the vacuum. We find that all the CP-nonconserving effects are mediated in our theory by the superheavy gauge bosons of the broken SU(4) x U(1) symmetry. In fact, the very existence of CP violation sets an upper limit on the masses of these bosons. In our model the dominant CP effect lies in the neutral kaon system and is found to arise through a direct (ΔS = 2) K 1 -K 2 transition. The model has all the features of a superweak theory, with a neutron electric dipole moment substantially smaller than 10 -24 e cm

Calculations in the weak and crossover regions of SU(2) lattice gauge theory

International Nuclear Information System (INIS)

Greensite, J.; Hansson, T.H.; Hari Dass, N.D.; Lauwers, P.G.

1981-07-01

A calculational scheme for lattice gauge theory is proposed which interpolates between lowest order mean-field and full Monte-Carlo calculations. The method is to integrate over a restricted set of link variables in the functional integral, with the remainder fixed at their mean-field value. As an application the authors compute small SU(2) Wilson loops near and above the weak-to-strong coupling transition point. (Auth.)

Symmetry breaking and asymptotic freedom in colour SU(3) gauge models

International Nuclear Information System (INIS)

Ma, E.

1976-01-01

A class of quark models based on the colour gauge group SU(3) is shown to be asymptotically free despite the complete breakdown of local symmetry to guarantee infrared stability. The symmetry breakdown is achieved by the presence of elementary scalar fields either through the Higgs mechanism or dynamically as first proposed by Coleman and Weinberg. Asymptotic freedom is preserved by imposing eigenvalue conditions on the coupling constants as first proposed by Chang. New quark species must be present, but below their production threshold, colour can still be a global symmetry which is approximate under SU(3), but exact under SU(2). Among the many implications of this class of models is the possibility of producing isolated quarks and gluons of non-zero mass without altering the short-distance behaviour of the superstrong interaction which binds them. (Auth.)

Gauge-Higgs unification in higher dimensions

International Nuclear Information System (INIS)

Hall, Lawrence; Nomura, Yasunori; Smith, David

2002-01-01

The electroweak Higgs doublets are identified as components of a vector multiplet in a higher-dimensional supersymmetric field theory. We construct a minimal model in 6D where the electroweak SU(2)xU(1) gauge group is extended to SU(3), and unified 6D models with the unified SU(5) gauge symmetry extended to SU(6). In these realistic theories the extended gauge group is broken by orbifold boundary conditions, leaving Higgs doublet zero modes which have Yukawa couplings to quarks and leptons on the orbifold fixed points. In one SU(6) model the weak mixing angle receives power law corrections, while in another the fixed point structure forbids such corrections. A 5D model is also constructed in which the Higgs doublet contains the fifth component of the gauge field. In this case Yukawa couplings are introduced as nonlocal operators involving the Wilson line of this gauge field

U(1) x SU(2) Chern-Simons gauge theory of underdoped cuprate superconductors

International Nuclear Information System (INIS)

Marchetti, P.A.; Su Zhao-Bin; Yu Lu

1998-05-01

The Chern-Simons bosonization with U(1)xSU(2) gauge field is applied to the 2-D t-J model in the limit t>>J, to study the normal state properties of underdoped cuprate superconductors. We prove the existence of an upper bound on the partition function for holons in a spinon background, and we find the optimal spinon configuration saturating the upper bound on average - a coexisting flux phase and s+id-like RVB state. After neglecting the feedback of holon fluctuations on the U(1) field B and spinon fluctuations on the SU(2) field V, the holon field is a fermion and the spinon field is a hard-core boson. Within this approximation we show that the B field produces a π flux phase for the holons, converting them into Dirac-like fermions, while the V field, taking into account the feedback of holons produces a gap for the spinons vanishing in the zero doping limit. The nonlinear σ-model with a mass term describes the crossover from the short-ranged antiferromagnetic (AF) state in doped samples to long range AF order in reference compounds. Moreover, we derive a low-energy effective action in terms of spinons holons and a self-generated U(1) gauge field. Neglecting the gauge fluctuations, the holons are described by the Fermi liquid theory with a Fermi surface consisting of 4 ''half-pockets'' centered at (+-π/2,+-π/2) and one reproduces the results for the electron spectral function obtained in the mean field approximation, in agreement with the photoemission data on underdoped cuprates. The gauge fluctuations are not confining due to coupling to holons, but nevertheless yield an attractive interaction between spinons and holons leading to a bound state with electron quantum numbers. The renormalisation effects due to gauge fluctuations give rise to non-Fermi liquid behaviour for the composite electron, in certain temperature range showing the linear in T resistivity. This formalism provides a new interpretation of the spin gap in the underdoped superconductors

Mean field with corrections in lattice gauge theory

International Nuclear Information System (INIS)

Flyvbjerg, H.; Zuber, J.B.; Lautrup, B.

1981-12-01

A systematic expansion of the path integral for lattice gauge theory is performed around the mean field solution. In this letter the authors present the results for the pure gauge groups Z(2), SU(2) and SO(3). The agreement with Monte Carlo calculations is excellent. For the discrete group the calculation is performed with and without gauge fixing, whereas for the continuous groups gauge fixing is mandatory. In the case of SU(2) the absence of a phase transition is correctly signalled by mean field theory. (Auth.)

Faddeev-Senjanovic quantization of SU(n) N=2 supersymmetric gauge field system with a non-Abelian Chern-Simons topological term and its fractional spin

International Nuclear Information System (INIS)

Huang Yongchang; Huo Qiuhong

2008-01-01

Using Faddeev-Senjanovic path integral quantization for constrained Hamilton system, we quantize SU(n) N=2 supersymmetric gauge field system with non-Abelian Chern-Simons topological term in 2+1 dimensions. We use consistency of Coulomb gauge condition to naturally deduce a new gauge condition. Furthermore, we obtain the generating functional of Green function in phase space, deduce the angular momentum based on the global canonical Noether theorem at quantum level, obtain the fractional spin of this supersymmetric system, and show that the total angular momentum is the sum of the orbital angular momentum and spin angular momentum of the non-Abelian gauge field. Finally, we obtain the anomalous fractional spin and discover that the fractional spin has the contributions of both the group superscript components and A 0 s (x) charge

Recursive relations for a quiver gauge theory

International Nuclear Information System (INIS)

Park, Jaemo; Sim, Woojoo

2006-01-01

We study the recursive relations for a quiver gauge theory with the gauge group SU(N 1 ) x SU(N 2 ) with bifundamental fermions transforming as (N 1 , N-bar 2 ). We work out the recursive relation for the amplitudes involving a pair of quark and antiquark and gluons of each gauge group. We realize directly in the recursive relations the invariance under the order preserving permutations of the gluons of the first and the second gauge group. We check the proposed relations for MHV, 6-point and 7-point amplitudes and find the agreements with the known results and the known relations with the single gauge group amplitudes. The proposed recursive relation is much more efficient in calculating the amplitudes than using the known relations with the amplitudes of the single gauge group

The Effective Prepotential of N=2 Supersymmetric $SU(N_c)$ Gauge Theories

CERN Document Server

D'Hoker, Eric; Phong, D.H.; D'Hoker, Eric

1996-01-01

We determine the effective prepotential for N=2 supersymmetric SU(N_c) gauge theories with an arbitrary number of flavors N_f < 2N_c, from the exact solution constructed out of spectral curves. The prepotential is the same for the several models of spectral curves proposed in the literature. It has to all orders the logarithmic singularities of the one-loop perturbative corrections, thus confirming the non-renormalization theorems from supersymmetry. In particular, the renormalized order parameters and their duals have all the correct monodromy transformations prescribed at weak coupling. We evaluate explicitly the contributions of one- and two-instanton processes.

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

Indefinite harmonic forms and gauge theory

International Nuclear Information System (INIS)

Nakashima, M.

1988-01-01

Indecomposable representations have been extensively used in the construction of conformal and de Sitter gauge theories. It is thus noteworthy that certain unitary highest weight representations have been given a geometric realization as the unitary quotient of an indecomposable representation using indefinite harmonic forms [RSW]. We apply this construction to SU(2,2) and the de Sitter group. The relation is established between these representations and the massless, positive energy representations of SU(2,2) obtained in the physics literature. We investigate the extent to which this construction allows twistors to be viewed as a gauge theory of SU(2,2). For the de Sitter group, on which the gauge theory of singletons is based, we find that this construction is not directly applicable. (orig.)

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

Gradient flow coupling in the SU(2) gauge theory with two adjoint fermions

DEFF Research Database (Denmark)

Rantaharju, Jarno

2016-01-01

We study SU(2) gauge theory with two fermion flavors in the adjoint representation. Using a clover improved HEX smeared action and the gradient flow running coupling allows us to simulate with larger lattice size than before. We find an infrared fixed point after a continuum extrapolation in the ...... in the range 4.3g∗24.8. We also measure the mass anomalous dimension and find the value 0.25γ∗0.28 at the fixed point....

Exceptional confinement in G(2) gauge theory

International Nuclear Information System (INIS)

Holland, K.; Minkowski, P.; Pepe, M.; Wiese, U.-J.

2003-01-01

We study theories with the exceptional gauge group G(2). The 14 adjoint 'gluons' of a G(2) gauge theory transform as {3}, {3-bar} and {8} under the subgroup SU(3), and hence have the color quantum numbers of ordinary quarks, anti-quarks and gluons in QCD. Since G(2) has a trivial center, a 'quark' in the {7} representation of G(2) can be screened by 'gluons'. As a result, in G(2) Yang-Mills theory the string between a pair of static 'quarks' can break. In G(2) QCD there is a hybrid consisting of one 'quark' and three 'gluons'. In supersymmetric G(2) Yang-Mills theory with a {14} Majorana 'gluino' the chiral symmetry is Z(4) χ . Chiral symmetry breaking gives rise to distinct confined phases separated by confined-confined domain walls. A scalar Higgs field in the {7} representation breaks G(2) to SU(3) and allows us to interpolate between theories with exceptional and ordinary confinement. We also present strong coupling lattice calculations that reveal basic features of G(2) confinement. Just as in QCD, where dynamical quarks break the Z(3) symmetry explicitly, G(2) gauge theories confine even without a center. However, there is not necessarily a deconfinement phase transition at finite temperature

Towards a multigrid scheme in SU(2) lattice gauge theory

International Nuclear Information System (INIS)

Gutbrod, F.

1992-12-01

The task of constructing a viable updating multigrid scheme for SU(2) lattice gauge theory is discussed in connection with the classical eigenvalue problem. For a nonlocal overrelaxation Monte Carlo update step, the central numerical problem is the search for the minimum of a quadratic approximation to the action under nonlocal constraints. Here approximate eigenfunctions are essential to reduce the numerical work, and these eigenfunctions are to be constructed with multigrid techniques. A simple implementation on asymmetric lattices is described, where the grids are restricted to 3-dimensional hyperplanes. The scheme is shown to be moderately successful in the early stages of the updating history (starting from a cold configuration). The main results of another, less asymmetric scheme are presented briefly. (orig.)

Global analysis of general SU(2)xSU(2)xU(1) models with precision data

International Nuclear Information System (INIS)

Hsieh, Ken; Yu, Jiang-Hao; Yuan, C.-P.; Schmitz, Kai

2010-01-01

We present the results of a global analysis of a class of models with an extended electroweak gauge group of the form SU(2)xSU(2)xU(1), often denoted as G(221) models, which include as examples the left-right, the leptophobic, the hadrophobic, the fermiophobic, the un-unified, and the nonuniversal models. Using an effective Lagrangian approach, we compute the shifts to the coefficients in the electroweak Lagrangian due to the new heavy gauge bosons, and obtain the lower bounds on the masses of the Z ' and W ' bosons. The analysis of the electroweak parameter bounds reveals a consistent pattern of several key observables that are especially sensitive to the effects of new physics and thus dominate the overall shape of the respective parameter contours.

Global analysis of general SU(2) x SU(2) x U(1) models with precision data

International Nuclear Information System (INIS)

Hsieh, Ken; Yu, Jiang-Hao; Yuan, C.P.; Schmitz, Kai; Michigan State Univ., East Lansing, MI

2010-05-01

We present the results of a global analysis of a class of models with an extended electroweak gauge group of the form SU(2) x SU(2) x U(1), often denoted as G(221) models, which include as examples the left-right, the lepto-phobic, the hadro-phobic, the fermio-phobic, the un-unified, and the non-universal models. Using an effective Lagrangian approach, we compute the shifts to the coeffcients in the electroweak Lagrangian due to the new heavy gauge bosons, and obtain the lower bounds on the masses of the Z' and W' bosons. The analysis of the electroweak parameter bounds reveals a consistent pattern of several key observables that are especially sensitive to the effects of new physics and thus dominate the overall shape of the respective parameter contours. (orig.)

Topological charge in non-abelian lattice gauge theory

International Nuclear Information System (INIS)

Lisboa, P.

1983-01-01

We report on a numerical calculation of topological charge densities in non-abelian gauge theory with gauge groups SU(2) and SU(3). The group manifold is represented by a discrete subset thereof which lies outside its finite subgroups. The results shed light on the usefulness of these representations in Monte Carlo evaluations of non-abelian lattice gauge theory. (orig.)

Dimensional reduction of exceptional E6,E8 gauge groups and flavour chirality

International Nuclear Information System (INIS)

Koca, M.

1984-01-01

Ten-dimensional Yang - Mills gauge theories based on the exceptional groups E 6 and E 8 are reduced to four-dimensional flavour-chiral Yang - Mills - Higgs theories where the extra six dimensions are identified with the compact G 2 /SU(3) and SO(7)/SO(6) coset spaces. A ten-dimensional E 8 theory leads to three families of SU(5), one of which lies in the 144-dimensional representation of SO(10)

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

When rational sections become cyclic — Gauge enhancement in F-theory via Mordell-Weil torsion

Science.gov (United States)

Baume, Florent; Cvetič, Mirjam; Lawrie, Craig; Lin, Ling

2018-03-01

We explore novel gauge enhancements from abelian to non-simply-connected gauge groups in F-theory. To this end we consider complex structure deformations of elliptic fibrations with a Mordell-Weil group of rank one and identify the conditions under which the generating section becomes torsional. For the specific case of ℤ2 torsion we construct the generic solution to these conditions and show that the associated F-theory compactification exhibits the global gauge group [SU(2) × SU(4)]/ℤ2 × SU(2). The subsolution with gauge group SU(2)/ℤ2 × SU(2), for which we provide a global resolution, is related by a further complex structure deformation to a genus-one fibration with a bisection whose Jacobian has a ℤ2 torsional section. While an analysis of the spectrum on the Jacobian fibration reveals an SU(2)/ℤ2 × ℤ2 gauge theory, reproducing this result from the bisection geometry raises some conceptual puzzles about F-theory on genus-one fibrations.

Linked cluster expansion in the SU(2) lattice Higgs model at strong gauge coupling

International Nuclear Information System (INIS)

Wagner, C.E.M.

1989-01-01

A linked cluster expansion is developed for the β=0 limit of the SU(2) Higgs model. This method, when combined with strong gauge coupling expansions, is used to obtain the phase transition surface and the behaviour of scalar and vector masses in the lattice regularized theory. The method, in spite of the low order of truncation of the series applied, gives a reasonable agreement with Monte Carlo data for the phase transition surface and a qualitatively good picture of the behaviour of Higgs, glueball and gauge vector boson masses, in the strong coupling limit. Some limitations of the method are discussed, and an intuitive picture of the different behaviour for small and large bare self-coupling λ is given. (orig.)

SU(N) gauge theories in 2+1 dimensions: glueball spectra and k-string tensions

Energy Technology Data Exchange (ETDEWEB)

Athenodorou, Andreas [Department of Physics, University of Cyprus,POB 20537, 1678 Nicosia (Cyprus); Computation-based Science and Technology Research Center, The Cyprus Institute,20 Kavafi Str., Nicosia 2121 (Cyprus); Teper, Michael [Rudolf Peierls Centre for Theoretical Physics, University of Oxford,1 Keble Road, Oxford OX1 3NP (United Kingdom)

2017-02-03

We calculate the low-lying glueball spectrum and various string tensions in SU(N) lattice gauge theories in 2+1 dimensions, and extrapolate the results to the continuum limit. We do so for for the range N∈[2,16] so as to control the N-dependence with a useful precision. We observe a number of striking near-degeneracies in the various J{sup PC} sectors of the glueball spectrum, in particular between C=+ and C=− states. We calculate the string tensions of flux tubes in a number of representations, and provide evidence that the leading correction to the N-dependence of the k-string tensions is ∝1/N rather than ∝1/N{sup 2}, and that the dominant binding of k fundamental flux tubes into a k-string is via pairwise interactions. We comment on the possible implications of our results for the dynamics of these gauge theories.

Global analysis of general SU(2) x SU(2) x U(1) models with precision data

Energy Technology Data Exchange (ETDEWEB)

Hsieh, Ken; Yu, Jiang-Hao; Yuan, C.P. [Michigan State Univ., East Lansing, MI (United States). Dept. of Physics and Astronomy; Schmitz, Kai [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Michigan State Univ., East Lansing, MI (United States). Dept. of Physics and Astronomy

2010-05-15

We present the results of a global analysis of a class of models with an extended electroweak gauge group of the form SU(2) x SU(2) x U(1), often denoted as G(221) models, which include as examples the left-right, the lepto-phobic, the hadro-phobic, the fermio-phobic, the un-unified, and the non-universal models. Using an effective Lagrangian approach, we compute the shifts to the coeffcients in the electroweak Lagrangian due to the new heavy gauge bosons, and obtain the lower bounds on the masses of the Z' and W' bosons. The analysis of the electroweak parameter bounds reveals a consistent pattern of several key observables that are especially sensitive to the effects of new physics and thus dominate the overall shape of the respective parameter contours. (orig.)

Zero of the discrete beta function in SU(3) lattice gauge theory with color sextet fermions

International Nuclear Information System (INIS)

Shamir, Yigal; Svetitsky, Benjamin; DeGrand, Thomas

2008-01-01

We have carried out a Schrodinger functional calculation for the SU(3) lattice gauge theory with two flavors of Wilson fermions in the sextet representation of the gauge group. We find that the discrete beta function, which governs the change in the running coupling under a discrete change of spatial scale, changes sign when the Schrodinger functional renormalized coupling is in the neighborhood of g 2 =2.0. The simplest explanation is that the theory has an infrared-attractive fixed point, but more complicated possibilities are allowed by the data. While we compare rescalings by factors of 2 and 4/3, we work at a single lattice spacing.

On exact correlation functions in SU(N) $ \\mathcal{N}=2 $ superconformal QCD

CERN Document Server

Baggio, Marco; Papadodimas, Kyriakos

2015-01-01

We consider the exact coupling constant dependence of extremal correlation functions of ${\\cal N} = 2$ chiral primary operators in 4d ${\\cal N} = 2$ superconformal gauge theories with gauge group SU(N) and N_f=2N massless fundamental hypermultiplets. The 2- and 3-point functions, viewed as functions of the exactly marginal coupling constant and theta angle, obey the tt* equations. In the case at hand, the tt* equations form a set of complicated non-linear coupled matrix equations. We point out that there is an ad hoc self-consistent ansatz that reduces this set of partial differential equations to a sequence of decoupled semi-infinite Toda chains, similar to the one encountered previously in the special case of SU(2) gauge group. This ansatz requires a surprising new non-renormalization theorem in ${\\cal N} = 2$ superconformal field theories. We derive a general 3-loop perturbative formula for 2- and 3-point functions in the ${\\cal N} = 2$ chiral ring of the SU(N) theory, and in all explicitly computed exampl...

Exceptional gauge groups and quantum theory

International Nuclear Information System (INIS)

Horwitz, L.P.; Biedenharn, L.C.

1979-01-01

It is shown that a Hilbert space over the real Clifford algebra C 7 provides a mathematical framework, consistent with the structure of the usual quantum mechanical formalism, for models for the unification of weak, electromagnetic and strong interactions utilizing the exceptional Lie groups. In particular, in case no further structure is assumed beyond that of C 7 , the group of automorphisms leaving invariant a minimal subspace acts, in the ideal generated by that subspace, as G 2 , and the subgroup of this group leaving one generating element (e 7 ) fixed acts, in this ideal, as the color gauge group SU(3). A generalized phase algebra AcontainsC 7 is defined by the requirement that quantum mechanical states can be consistently constructed for a theory in which the smallest linear manifolds are closed over the subalgebra C(1,e 7 ) (isomorphic to the complex field) of C 7 . Eight solutions are found for the generalized phase algebra, corresponding (up to an overall sign), in effect, to the use of +- e 7 as imaginary unit in each of four superselection sectors. Operators linear over these alternative forms of imanary unit provide distinct types of ''lepton--quark'' and ''quark--quark'' transitions. The subgroup in A which leaves expectation values of operators linear over A invariant is its unitary subgroup U(4), and is a realization (explicitly constructed) of the U(4) invariance of the complex scalar product. An embedding of the algebraic Hilbert space into the complex space defined over C(1,e 7 ) is shown to lead to a decomposition into ''lepton and ''quark'' superselection subspaces. The color SU(3) subgroup of G 2 coincides with the SU(3) subgroup of the generalized phase U(4) which leaves the ''lepton'' space invariant. The problem of constructing tensor products is studied, and some remarks are made on observability and the role of nonassociativity

Solvable spectral problems from 2d CFT and \\mathscr{N} = 2 gauge theories

Science.gov (United States)

Piątek, M. R.; Pietrykowski, A. R.

2018-02-01

The so-called 2d/4d correspondences connect two-dimensional conformal field theory (2d CFT), \\mathscr{N} = 2 supersymmetric gauge theories and quantum integrable systems. The latter in the simplest case of the SU(2) gauge group are nothing but the quantum-mechanical systems. In the present article we summarize our recent results and list open problems concerning an application of the aforementioned dualities in the studies of spectral problems for some Schrödinger operators with Mathieu-type periodic, periodic PT-symmetric and (Heun’s) elliptic potentials.

Estimating q-hat in Quenched Lattice SU(2) Gauge Theory

International Nuclear Information System (INIS)

Majumder, Abhijit

2013-01-01

The propagation of a virtual quark in a thermal medium is considered. The non-perturbative jet transport coefficient q -hat is estimated in quark less SU(2) lattice gauge theory. The light like correlator which defines q -hat , defined in the regime where the jet has small virtuality compared to its energy, is analytically related to a series of local operators in the deep Euclidean region, where the jet's virtuality is of the same order as its energy. It is demonstrated that in this region, for temperatures in the range of T=400–600 MeV, and for jet energies above 20 GeV, the leading term in the series is dominant over the next-to-leading term and thus yields an estimate of the value of q -hat . In these proceedings we discuss the details of the numerical calculation

4d N=2 theories with disconnected gauge groups

Energy Technology Data Exchange (ETDEWEB)

Argyres, Philip C.; Martone, Mario [Physics Department, University of Cincinnati,PO Box 210011, Cincinnati OH 45221 (United States)

2017-03-28

In this paper we present a beautifully consistent web of evidence for the existence of interacting 4d rank-1 N=2 SCFTs obtained from gauging discrete subgroups of global symmetries of other existing 4d rank-1 N=2 SCFTs. The global symmetries that can be gauged involve a non-trivial combination of discrete subgroups of the U(1){sub R}, low-energy EM duality group SL(2,ℤ), and the outer automorphism group of the flavor symmetry algebra, Out(F). The theories that we construct are remarkable in many ways: (i) two of them have exceptional F{sub 4} and G{sub 2} flavor groups; (ii) they substantially complete the picture of the landscape of rank-1 N=2 SCFTs as they realize all but one of the remaining consistent rank-1 Seiberg-Witten geometries that we previously constructed but were not associated to known SCFTs; and (iii) some of them have enlarged N=3 SUSY, and have not been previously constructed. They are also examples of SCFTs which violate the Shapere-Tachikawa relation between the conformal central charges and the scaling dimension of the Coulomb branch vev. We propose a modification of the formulas computing these central charges from the topologically twisted Coulomb branch partition function which correctly compute them for discretely gauged theories.

N=2, 4 supersymmetric gauge field theory in two-time physics

International Nuclear Information System (INIS)

Bars, Itzhak; Kuo, Y.-C.

2009-01-01

In the context of two-time physics in 4+2 dimensions we construct the most general N=2, 4 supersymmetric Yang-Mills gauge theories for any gauge group G. This builds on our previous work for N=1 supersymmetry (SUSY). The action, the conserved SUSY currents, and the SU(N) covariant SUSY transformation laws are presented for both N=2 and N=4. When the equations of motion are used the SUSY transformations close to the supergroup SU(2,2|N) with N=1, 2, 4. The SU(2,2)=SO(4,2) subsymmetry is realized linearly on 4+2 dimensional flat spacetime. All fields, including vectors and spinors, are in 4+2 dimensions. The extra gauge symmetries in 2T field theory, together with the kinematic constraints that follow from the action, remove all the ghosts to give a unitary theory. By choosing gauges and solving the kinematic equations, the 2T field theory in 4+2 flat spacetime can be reduced to various shadows in various 3+1 dimensional (generally curved) spacetimes. These shadows are related to each other by dualities. The conformal shadows of our theories in flat 3+1 dimensions coincide with the well known counterpart N=1, 2, 4 supersymmetric massless renormalizable field theories in 3+1 dimensions. It is expected that our more symmetric new structures in 4+2 spacetime may be useful for nonperturbative or exact solutions of these theories.

Phase structure of lattice gauge theories for non-abelian subgroups of SU(3)

International Nuclear Information System (INIS)

Grosse, H.; Kuehnelt, H.

1981-01-01

The authors study the phase structure of Euclidean lattice gauge theories in four dimensions for certain non-abelian subgroups of SU(3) by using Monte-Carlo simulations and strong coupling expansions. As the order of the group increases a splitting of one phase transition into two is observed. (Auth.)

SU(3) lattice gauge fixing with overrelaxation and Gribov copies

Energy Technology Data Exchange (ETDEWEB)

Paciello, M.L.; Taglienti, B. (INFN La Sapienza, Rome (Italy)); Parrinello, C. (Physics Dept., New York Univ., NY (United States)); Petrarca, S. (Theory Div., CERN, Geneva (Switzerland)); Vladikas, A. (Dipt. di Fisica, Univ. Tor Vergata, Rome (Italy) INFN Tor Vergata, Rome (Italy))

1992-02-06

We report on the phenomenology of SU(3) lattice Landau gauge fixing as obtained by using an overrelaxation algorithm. An interesting result obtained using this very efficient algorithm is that distinct Gribov copies are generated by simply modifying the value {omega} of the overrelaxation parameter for a fixed starting configuration. By generating random gauge equivalent configurations, we study the variation of the number of copies with the lattice volume and gauge coupling. (orig.).

$SU(2)$ gauge theory with two fundamental flavours: scalar and pseudoscalar spectrum

CERN Document Server

Arthur, Rudy; Hietanen, Ari; Pica, Claudio; Sannino, Francesco

2016-01-01

We investigate the scalar and pseudoscalar spectrum of the $SU(2)$ gauge theory with $N_f=2$ flavours of fermions in the fundamental representation using non perturbative lattice simulations. We provide first benchmark estimates of the mass of the lightest $0(0^{+})$ ($\\sigma$), $0(0^{-})$ ($\\eta'$) and $1(0^+)$ ($a_0$) states, including estimates of the relevant disconnected contributions. We find $m_{a_0}/F_{\\rm{PS}}= 16.7(4.9)$, $m_\\sigma/F_{\\rm{PS}}=19.2(10.8)$ and $m_{\\eta'}/F_{\\rm{PS}} = 12.8(4.7)$. These values for the masses of light scalar states provide crucial information for composite extensions of the Standard Model from the unified Fundamental Composi te Higgs-Technicolor theory \\cite{Cacciapaglia:2014uja} to models of composite dark matter.

Efficient basis formulation for 1+1 dimensional SU(2) lattice gauge theory. Spectral calculations with matrix product states

Energy Technology Data Exchange (ETDEWEB)

Banuls, Mari Carmen; Cirac, J. Ignacio; Kuehn, Stefan [Max-Planck-Institut fuer Quantenoptik (MPQ), Garching (Germany); Cichy, Krzysztof [Frankfurt Univ. (Germany). Inst. fuer Theoretische Physik; Adam Mickiewicz Univ., Poznan (Poland). Faculty of Physics; Jansen, Karl [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC

2017-07-20

We propose an explicit formulation of the physical subspace for a 1+1 dimensional SU(2) lattice gauge theory, where the gauge degrees of freedom are integrated out. Our formulation is completely general, and might be potentially suited for the design of future quantum simulators. Additionally, it allows for addressing the theory numerically with matrix product states. We apply this technique to explore the spectral properties of the model and the effect of truncating the gauge degrees of freedom to a small finite dimension. In particular, we determine the scaling exponents for the vector mass. Furthermore, we also compute the entanglement entropy in the ground state and study its scaling towards the continuum limit.

Efficient Basis Formulation for (1+1-Dimensional SU(2 Lattice Gauge Theory: Spectral Calculations with Matrix Product States

Directory of Open Access Journals (Sweden)

Mari Carmen Bañuls

2017-11-01

Full Text Available We propose an explicit formulation of the physical subspace for a (1+1-dimensional SU(2 lattice gauge theory, where the gauge degrees of freedom are integrated out. Our formulation is completely general, and might be potentially suited for the design of future quantum simulators. Additionally, it allows for addressing the theory numerically with matrix product states. We apply this technique to explore the spectral properties of the model and the effect of truncating the gauge degrees of freedom to a small finite dimension. In particular, we determine the scaling exponents for the vector mass. Furthermore, we also compute the entanglement entropy in the ground state and study its scaling towards the continuum limit.

Efficient Basis Formulation for (1 +1 )-Dimensional SU(2) Lattice Gauge Theory: Spectral Calculations with Matrix Product States

Science.gov (United States)

Bañuls, Mari Carmen; Cichy, Krzysztof; Cirac, J. Ignacio; Jansen, Karl; Kühn, Stefan

2017-10-01

We propose an explicit formulation of the physical subspace for a (1 +1 )-dimensional SU(2) lattice gauge theory, where the gauge degrees of freedom are integrated out. Our formulation is completely general, and might be potentially suited for the design of future quantum simulators. Additionally, it allows for addressing the theory numerically with matrix product states. We apply this technique to explore the spectral properties of the model and the effect of truncating the gauge degrees of freedom to a small finite dimension. In particular, we determine the scaling exponents for the vector mass. Furthermore, we also compute the entanglement entropy in the ground state and study its scaling towards the continuum limit.

Efficient basis formulation for 1+1 dimensional SU(2) lattice gauge theory. Spectral calculations with matrix product states

International Nuclear Information System (INIS)

Banuls, Mari Carmen; Cirac, J. Ignacio; Kuehn, Stefan; Cichy, Krzysztof; Adam Mickiewicz Univ., Poznan; Jansen, Karl

2017-01-01

We propose an explicit formulation of the physical subspace for a 1+1 dimensional SU(2) lattice gauge theory, where the gauge degrees of freedom are integrated out. Our formulation is completely general, and might be potentially suited for the design of future quantum simulators. Additionally, it allows for addressing the theory numerically with matrix product states. We apply this technique to explore the spectral properties of the model and the effect of truncating the gauge degrees of freedom to a small finite dimension. In particular, we determine the scaling exponents for the vector mass. Furthermore, we also compute the entanglement entropy in the ground state and study its scaling towards the continuum limit.

Gauge hierarchy problem and a nonscaling SU(5) model

International Nuclear Information System (INIS)

Tajnov, Eh.A.

1987-01-01

It is shown that the problems of gauge hierarchy anf Higgs hierarchy have a common origin, and a way is proposed for their combined solution in a no-scale supersymmetric SU(5) gauge model, related to the N=1 supergravity. A reason of appearance of the grand unification scale, M G , is the dimensional transmutation owing to quantum corrections to the classical potential. In this model, the Higgs hierarchy is established automatically by means of the singlet mechanism, which does not require a fine tuning of the superpotential parameters. The effective potential for the singlet field X has a minimum at =M G =2.2x10 16 GeV. The scale parameter M G does not depend on the gravitino mass and initial values of the Yukawa coupling constants but depends on initial values of the gauge constant α -1 (0)=22.7 and on the trilinear supergravity constant A=1.84 at a scale M=M p /√8π=2.43x10 18 GeV

Deconfinement phase transition and finite-size scaling in SU(2) lattice gauge theory

International Nuclear Information System (INIS)

Mogilevskij, O.A.

1988-01-01

Calculation technique for deconfinement phase transition parameters based on application of finite-size scaling theory is suggested. The essence of the technique lies in plotting of universal scaling function on the basis of numerical data obtained at different-size final lattices and discrimination of phase transition parameters for infinite lattice system. Finite-size scaling technique was developed as applied to spin system theory. β critical index for Polyakov loop and SU(2) deconfinement temperature of lattice gauge theory are calculated on the basis of finite-size scaling technique. The obtained value agrees with critical index of magnetization in Ising three-dimensional model

Relations between the SU(2|4) symmetric theories and the gauge gravity correspondence

International Nuclear Information System (INIS)

Tsuchiya, Asato

2008-01-01

We study theories with SU(2|4) symmetry, which include N=4 SYM on R x S 3 /Z k , 2+1 SYM on R x S 2 and the plane wave matrix model. All these theories possess many vacua. From Lin-Maldacena's method which gives the gravity dual of each vacuum, it is suggested that the theory around each vacuum of N=4 SYM on R x S 3 /Z k and 2+1 SYM on R x S 2 is equivalent to the theory around a certain vacuum of the plane wave matrix model. We show this directly on the gauge theory side. We realize theories around multi-monopole backgrounds in matrix model, and extend Taylor's matrix T-duality to that on spheres. (author)

Building up the standard gauge model of high energy physics. 11

International Nuclear Information System (INIS)

Rajasekaran, G.

1989-01-01

This chapter carefully builds up, step by step, the standard gauge model of particle physics based on the group SU(3) c x SU(2) x U(1). Spontaneous symmetry breaking via the Nambu-Goldstone mode, and then via the Higgs mode for gauge theories, are presented via examples, first for the Abelian U(1) and then for the non-Abelian SU(2) case. The physically interesting SU(2) x U(1) model is then taken up. The emergence of massive vector bosons is demonstrated. After this preparation, the 'standard model' of the late 60's prior to the gauge theory revolution, based on the V-A current-current weak interactions, minimal electromagnetism, and an unspecified strong interaction, all in quark-lepton language, is set up. It is then compared to the standard gauge model of SU(3) c x SU(2) x U(1). The compelling reasons for QCD as the gauge theory of strong interactions are spelt out. An introduction to renormalization group methods as the main calculational tool for QCD, asymptotic freedom, infrared problems, and physically motivated reasons for going beyond the standard model are presented. (author). 6 refs.; 19 figs.; 2 tabs

Individual eigenvalue distributions of crossover chiral random matrices and low-energy constants of SU(2) × U(1) lattice gauge theory

Science.gov (United States)

Yamamoto, Takuya; Nishigaki, Shinsuke M.

2018-02-01

We compute individual distributions of low-lying eigenvalues of a chiral random matrix ensemble interpolating symplectic and unitary symmetry classes by the Nyström-type method of evaluating the Fredholm Pfaffian and resolvents of the quaternion kernel. The one-parameter family of these distributions is shown to fit excellently the Dirac spectra of SU(2) lattice gauge theory with a constant U(1) background or dynamically fluctuating U(1) gauge field, which weakly breaks the pseudoreality of the unperturbed SU(2) Dirac operator. The observed linear dependence of the crossover parameter with the strength of the U(1) perturbations leads to precise determination of the pseudo-scalar decay constant, as well as the chiral condensate in the effective chiral Lagrangian of the AI class.

Coulomb branches for rank 2 gauge groups in 3dN=4 gauge theories

Energy Technology Data Exchange (ETDEWEB)

Hanany, Amihay [Theoretical Physics Group, Imperial College London,Prince Consort Road, London, SW7 2AZ (United Kingdom); Sperling, Marcus [Institut für Theoretische Physik, Leibniz Universität Hannover,Appelstraße 2, 30167 Hannover (Germany)

2016-08-02

The Coulomb branch of 3-dimensional N=4 gauge theories is the space of bare and dressed BPS monopole operators. We utilise the conformal dimension to define a fan which, upon intersection with the weight lattice of a GNO-dual group, gives rise to a collection of semi-groups. It turns out that the unique Hilbert bases of these semi-groups are a sufficient, finite set of monopole operators which generate the entire chiral ring. Moreover, the knowledge of the properties of the minimal generators is enough to compute the Hilbert series explicitly. The techniques of this paper allow an efficient evaluation of the Hilbert series for general rank gauge groups. As an application, we provide various examples for all rank two gauge groups to demonstrate the novel interpretation.

Unconstrained SU(2) and SU(3) Yang-Mills classical mechanics

International Nuclear Information System (INIS)

Dahmen, B.; Raabe, B.

1992-01-01

A systematic study of contraints in SU(2) and SU(3) Yang-Mills classical mechanics is performed. Expect for the SU(2) case with spatial angular momenta they turn out to be nonholonomic. The complete elimination of the unphysical gauge and rotatinal degrees of freedom is achieved using Dirac's constraint formalism. We present an effective unconstrained formulation of the general SU(2) Yang-Mills classical mechanics as well as for SU(3) in the subspace of vanishing spatial angular momenta that is well suited for further explicit dynamical investigations. (orig.)

Dynamics of SU(N) supersymmetric gauge theory

Energy Technology Data Exchange (ETDEWEB)

Douglas, M R [Rutgers - the State Univ., Piscataway, NJ (United States). Dept. of Physics and Astronomy; Shenker, S H [Rutgers - the State Univ., Piscataway, NJ (United States). Dept. of Physics and Astronomy

1995-08-07

We study the physics of the Seiberg-Witten and Argyres-Faraggi-Klemm-Lerche-Theisen-Yankielowicz solutions of D=4, N=2 and N=1 SU(N) supersymmetric gauge theory. The N=1 theory is confining and its effective Lagrangian is a spontaneously broken U(1){sup N-1} abelian gauge theory. We identify some features of its physics which see this internal structure, including a spectrum of different string tensions. We discuss the limit N{yields}{infinity}, identify a scaling regime in which instanton and monopole effects survive, and give exact results for the crossover from weak to strong coupling along a scaling trajectory. We find a large hierarchy of mass scales in the scaling regime, including very light W bosons, and the absence of weak coupling. The light W`s leave a novel imprint on the effective dual magnetic theory. The effective Lagrangian appears to be inadequate to understand the conventional large N limit of the confining N=1 theory. (orig.).

ɛ '/ ɛ anomaly and neutron EDM in SU(2) L × SU(2) R × U(1) B- L model with charge symmetry

Science.gov (United States)

Haba, Naoyuki; Umeeda, Hiroyuki; Yamada, Toshifumi

2018-05-01

The Standard Model prediction for ɛ '/ ɛ based on recent lattice QCD results exhibits a tension with the experimental data. We solve this tension through W R + gauge boson exchange in the SU(2) L × SU(2) R × U(1) B- L model with `charge symmetry', whose theoretical motivation is to attribute the chiral structure of the Standard Model to the spontaneous breaking of SU(2) R × U(1) B- L gauge group and charge symmetry. We show that {M_W}{_R}study a correlation between ɛ ' /ɛ and the neutron EDM. We confirm that the model can solve the ɛ ' /ɛ anomaly without conflicting the current bound on the neutron EDM, and further reveal that almost all parameter regions in which the ɛ ' /ɛ anomaly is explained will be covered by future neutron EDM searches, which leads us to anticipate the discovery of the neutron EDM.

New physics contribution to neutral trilinear gauge boson couplings

International Nuclear Information System (INIS)

Dutta, Sukanta; Mamta; Goyal, Ashok

2009-01-01

We study the one-loop new physics effects to the CP even triple neutral gauge boson vertices γ * γZ, γ * ZZ, Z * Zγ and Z * ZZ in the context of Little Higgs models. We compute the contribution of the additional fermions in Little Higgs models in the framework of direct product groups where [SU(2) x U(1)] 2 gauge symmetry is embedded in SU(5) global symmetry and also in the framework of the simple group where SU(N) x U(1) gauge symmetry breaks down to SU(2) L x U(1). We calculate the contribution of the fermions to these couplings when T parity is invoked. In addition, we re-examine the MSSM contribution at the chosen point of SPS1a ' and compare with the SM and Little Higgs models. (orig.)

Equivariant Reduction of Gauge Theories over Fuzzy Extra Dimensions

International Nuclear Information System (INIS)

Kürkçüoglu, Seçkin

2012-01-01

In SU(N) Yang-Mills theories on a manifold M, which are suitably coupled to a set of scalars, fuzzy spheres may be generated as extra dimensions by spontaneous symmetry breaking. This process results in gauge theories over the product space of the manifold M and the fuzzy spheres with smaller gauge groups. Here we present the SU(2)– and SU(2) × SU(2)-equivariant parametrization of U(2) and U(4) gauge fields on S 2 F and S 2 F × S 2 F respectively and outline the dimensional reduction of these theories over the fuzzy extra dimensions. The emerging dimensionally reduced theories are Higgs type models. Some vortex type solutions of these theories are briefly discussed.

[SU(2)]3 dark matter

Science.gov (United States)

Ma, Ernest

2018-05-01

An extra SU(2)D gauge factor is added to the well-known left-right extension of the standard model (SM) of quarks and leptons. Under SU(2)L × SU(2)R × SU(2)D, two fermion bidoublets (2 , 1 , 2) and (1 , 2 , 2) are assumed. The resulting model has an automatic dark U (1) symmetry, in the same way that the SM has automatic baryon and lepton U (1) symmetries. Phenomenological implications are discussed, as well as the possible theoretical origins of this proposal.

Properties of Gribov region and horizon function in the SU(N) Maximal Abelian Gauge

International Nuclear Information System (INIS)

Capri, Marcio Andre Lopes; Gomez, A.J.; Guimaraes, M.S.; Lemes, Vitor Emanuel Rodino; Sorella, Silvio Paolo

2011-01-01

Full text: The problem of the Gribov copies deals with the impossibility of to choose a unique gauge condition in the quantization process in the Yang Mills theories. In the Landau gauge, several properties of the Gribov region are established, the implementation of the Gribov copies in the path integral is taking account by the introduction of the horizon function directly in the action giving rise to modifications in the ghost and gluon propagator in the infrared regime. However, is interesting to looking at other gauge choices for obtain additional information of the phenomena, and compare our results in the landau gauge. In this work we address the issue of the Gribov copies in SU(N),N ¿ 2, Euclidean Yang-Mills theories quantized in the maximal Abelian gauge. A few properties of the Gribov region in this gauge are established. Similarly to the case of SU(2), the Gribov region turns out to be convex, bounded along the off-diagonals directions in field space, and unbounded along the diagonal ones. The implementation of the restriction to the Gribov region in the functional integral is discussed through the introduction of the horizon function, whose construction will be outlined in detail. The influence of this restriction on the behavior of the gluon and ghost propagators of the theory is also investigated together with a set of dimension two condensates. (author)

Gauge origin of discrete flavor symmetries in heterotic orbifolds

Directory of Open Access Journals (Sweden)

Florian Beye

2014-09-01

Full Text Available We show that non-Abelian discrete symmetries in orbifold string models have a gauge origin. This can be understood when looking at the vicinity of a symmetry enhanced point in moduli space. At such an enhanced point, orbifold fixed points are characterized by an enhanced gauge symmetry. This gauge symmetry can be broken to a discrete subgroup by a nontrivial vacuum expectation value of the Kähler modulus T. Using this mechanism it is shown that the Δ(54 non-Abelian discrete symmetry group originates from a SU(3 gauge symmetry, whereas the D4 symmetry group is obtained from a SU(2 gauge symmetry.

Noncommutative gauge theory and symmetry breaking in matrix models

International Nuclear Information System (INIS)

Grosse, Harald; Steinacker, Harold; Lizzi, Fedele

2010-01-01

We show how the fields and particles of the standard model can be naturally realized in noncommutative gauge theory. Starting with a Yang-Mills matrix model in more than four dimensions, an SU(n) gauge theory on a Moyal-Weyl space arises with all matter and fields in the adjoint of the gauge group. We show how this gauge symmetry can be broken spontaneously down to SU(3) c xSU(2) L xU(1) Q [resp. SU(3) c xU(1) Q ], which couples appropriately to all fields in the standard model. An additional U(1) B gauge group arises which is anomalous at low energies, while the trace-U(1) sector is understood in terms of emergent gravity. A number of additional fields arise, which we assume to be massive, in a pattern that is reminiscent of supersymmetry. The symmetry breaking might arise via spontaneously generated fuzzy spheres, in which case the mechanism is similar to brane constructions in string theory.

Three-index symmetric matter representations of SU(2) in F-theory from non-Tate form Weierstrass models

Energy Technology Data Exchange (ETDEWEB)

Klevers, Denis [Theoretical Physics Department, CERN,CH-1211 Geneva 23 (Switzerland); Taylor, Washington [Center for Theoretical Physics, Department of Physics, Massachusetts Institute of Technology,77 Massachusetts Avenue Cambridge, MA 02139 (United States)

2016-06-29

We give an explicit construction of a class of F-theory models with matter in the three-index symmetric (4) representation of SU(2). This matter is realized at codimension two loci in the F-theory base where the divisor carrying the gauge group is singular; the associated Weierstrass model does not have the form associated with a generic SU(2) Tate model. For 6D theories, the matter is localized at a triple point singularity of arithmetic genus g=3 in the curve supporting the SU(2) group. This is the first explicit realization of matter in F-theory in a representation corresponding to a genus contribution greater than one. The construction is realized by “unHiggsing” a model with a U(1) gauge factor under which there is matter with charge q=3. The resulting SU(2) models can be further unHiggsed to realize non-Abelian G{sub 2}×SU(2) models with more conventional matter content or SU(2){sup 3} models with trifundamental matter. The U(1) models used as the basis for this construction do not seem to have a Weierstrass realization in the general form found by Morrison-Park, suggesting that a generalization of that form may be needed to incorporate models with arbitrary matter representations and gauge groups localized on singular divisors.

Unconstrained SU(2) and SU(3) Yang-Mills clasical mechanics

International Nuclear Information System (INIS)

Dahmen, B.; Raabe, B.

1992-01-01

A systematic study of constraints in SU(2) and SU(3) Yang-Mills classical mechanics is performed. Expect for the SU(2) case with vanishing spatial angular momenta they turn out to be non-holonomic. Using Dirac's constraint formalism we achieve a complete elimination of the unphysical gauge and rotational degrees of freedom. This leads to an effective unconstrained formulation both for the full SU(2) Yang-Mills classical mechanics and for the SU(3) case in the subspace of vanishing spatial angular momenta. We believe that our results are well suited for further explicit dynamical investigations. (orig.)

Supersymmetric flipped SU(5) revitalized

Energy Technology Data Exchange (ETDEWEB)

Antoniadis, I.; Ellis, J.; Hagelin, J.S.; Nanopoulos, D.V.

1987-08-06

We describe a simple N = 1 supersymmetric GUT based on the group SU(5) x U(1) which has the following virtues: the gauge group is broken down to the SU(3)/sub C/ x SU(2)/sub L/ x U(1)/sub y/ of the standard model using just 10, 10 Higgs representations, and the doublet-triplet mass splitting problem is solved naturally by a very simple missing-partner mechanism. The successful supersymmetric GUT prediction for sin/sup 2/theta/sub w/ can be maintained, whilst there are no fermion mass relations. The gauge group and representation structure of the model may be obtainable from the superstring.

Self-dual gauge theories

International Nuclear Information System (INIS)

Zet, G.

2002-01-01

The self-duality equations are important in gauge theories because they show the connection between gauge models with internal symmetry groups and gauge theory of gravity. They are differential equations of the first order and it is easier to investigate the solutions for different particular configurations of the gauge fields and of space-times.One of the most important property of the self-duality equations is that they imply the Yang-Mills field equations. In this paper we will prove this property for the general case of a gauge theory with compact Lie group of symmetry over a 4-dimensional space-time manifold. It is important to remark that there are 3m independent self-duality equations (of the first order) while the number of Yang-Mills equations is equal to 4m, where m is the dimension of the gauge group. Both of them have 4m unknown functions which are the gauge potentials A μ a (x), a = 1, 2, ....,m; μ = 0, 1, 2, 3. But, we have, in addition, m gauge conditions for A μ a (x), (for example Coulomb, Lorentz or axial gauge) which together with the selfduality equation constitute a system of 4m equations. The Bianchi identities for the self-dual stress tensor F μν a coincide with the Yang-Mills equations and do not imply therefore supplementary conditions. We use the axial gauge in order to obtain the self duality equations for a SU(2) gauge theory over a curved space-time. The compatibility between self-duality and Yang-Mills equations is studied and some classes of solutions are obtained. In fact, we will write the Einstein-Yang-Mills equations and we will analyse only the Yang-Mills sector. The Einstein equations can not be obtained of course from self-duality. They should be obtained if we would consider a gauge theory having P x SU(2) as symmetry group, where P is the Poincare group. More generally, a gauge theory of N-extended supersymmetry can be developed by imposing the self-duality condition. (author)

Weak mixing angle and the SU(3)CxSU(3) model on M4xS1/(Z2xZ'2)

International Nuclear Information System (INIS)

Li Tianjun; Wei Liao

2002-05-01

We show that the desirable weak mixing angle sin 2 θ W =0.2312 at m Z scale can be generated naturally in the SU(3) C xSU(3) model on M 4 xS 1 /(Z 2 x Z 2 ') where the gauge symmetry SU(3) is broken down to SU(2) L xU(1) Y by orbifold projection. For a supersymmetric model with a TeV scale extra dimension, the SU(3) unification scale is about hundreds of TeVs at which the gauge couplings for SU(3) C and SU(3) can also be equal in the mean time. For the non-supersymmetric model, SU(2) L xU(1) Y are unified at order of 10 TeV. These models may serve as good candidates for physics beyond the SM or MSSM. (author)

New physics contribution to neutral trilinear gauge boson couplings

Energy Technology Data Exchange (ETDEWEB)

Dutta, Sukanta; Mamta [University of Delhi, SGTB Khalsa College, Delhi (India); Goyal, Ashok [University of Delhi, Department of Physics and Astrophysics, Delhi (India)

2009-09-15

We study the one-loop new physics effects to the CP even triple neutral gauge boson vertices {gamma}{sup *}{gamma}Z, {gamma}{sup *}ZZ, Z{sup *}Z{gamma} and Z{sup *}ZZ in the context of Little Higgs models. We compute the contribution of the additional fermions in Little Higgs models in the framework of direct product groups where [SU(2) x U(1)]{sup 2} gauge symmetry is embedded in SU(5) global symmetry and also in the framework of the simple group where SU(N) x U(1) gauge symmetry breaks down to SU(2){sub L} x U(1). We calculate the contribution of the fermions to these couplings when T parity is invoked. In addition, we re-examine the MSSM contribution at the chosen point of SPS1a ' and compare with the SM and Little Higgs models. (orig.)

Compactifications of IIA supergravity on SU(2)-structure manifolds

Energy Technology Data Exchange (ETDEWEB)

Spanjaard, B.

2008-07-15

In this thesis, we study compactifications of type IIA supergravity on six-dimensional manifolds with an SU(2)-structure. A general study of six-dimensional manifolds with SU(2)-structure shows that IIA supergravity compactified on such a manifold should yield a four-dimensional gauged N=4 supergravity. We explicitly derive the bosonic spectrum, gauge transformations and action for IIA supergravity compactified on two different manifolds with SU(2)-structure, one of which also has an H{sup (3)}{sub 10}-flux, and confirm that the resulting four-dimensional theories are indeed N=4 gauged supergravities. In the second chapter, we study an explicit construction of a set of SU(2)-structure manifolds. This construction involves a Scherk-Schwarz duality twist reduction of the half-maximal six-dimensional supergravity obtained by compactifying IIA supergravity on a K3. This reduction results in a gauged N=4 four-dimensional supergravity, where the gaugings can be divided into three classes of parameters. We relate two of the classes to parameters we found before, and argue that the third class of parameters could be interpreted as a mirror flux. (orig.)

A preliminary study of the Gribov ambiguity in lattice SU(3) Coulomb gauge

Energy Technology Data Exchange (ETDEWEB)

Parrinello, C. (Physics Dept., New York Univ., NY (United States)); Petrarca, S. (Dipt. di Fisica, Rome-1 Univ. (Italy) INFN, Rome (Italy)); Vladikas, A. (Dipt. di Fisica, Rome-2 Univ. (Italy) INFN, Rome (Italy))

1991-10-10

We report on simulations of pure SU(3) gauge theory on a 10{sup 3}x20 lattice at {beta}=6.0 in the Coulomb gauge, from which the Gribov ambiguity appears to be maximal, in the sense that the gauge-fixing process is highly unstable with respect to variations of the starting configuration via random gauge transformations. We give a heuristic explanation of the larger number of Gribov copies in such a gauge with respect to the Landau gauge. (orig.).

Exceptional thermodynamics. The equation of state of G2 gauge theory

International Nuclear Information System (INIS)

Bruno, Mattia; Panero, Marco; Pellegrini, Roberto

2014-10-01

We present a lattice study of the equation of state in Yang-Mills theory based on the exceptional G 2 gauge group. As is well-known, at zero temperature this theory shares many qualitative features with real-world QCD, including the absence of colored states in the spectrum and dynamical string breaking at large distances. In agreement with previous works, we show that at finite temperature this theory features a first-order deconfining phase transition, whose nature can be studied by a semi-classical computation. We also show that the equilibrium thermodynamic observables in the deconfined phase bear striking quantitative similarities with those found in SU(N) gauge theories: in particular, these quantities exhibit nearly perfect proportionality to the number of gluon degrees of freedom, and the trace anomaly reveals a characteristic quadratic dependence on the temperature, also observed in SU(N) Yang-Mills theories (both in four and in three spacetime dimensions). We compare our lattice data with analytical predictions from effective models, and discuss their implications for the deconfinement mechanism and high-temperature properties of strongly interacting, non-supersymmetric gauge theories. Our results give strong evidence for the conjecture that the thermal deconfining transition is governed by a universal mechanism, common to all simple gauge groups.

The Wilson loop expectation values in 2-and 3-dimensional SU(2) LGT

International Nuclear Information System (INIS)

Li Zhibing; Zheng Weihong; Guo Shuohong

1989-01-01

An improved Monte Carlo scheme is applied to the computation of expectation values of nxm Wilson loops in both 2-and 3-dimensional SU(2) lattice gauge theories. The results are compared with those simulated by the discrete group Y 120 and the exact results in two dimensions

Two-loop ghost-antighost condensation for SU(2) Yang-Mills theories in the maximal abelian gauge

International Nuclear Information System (INIS)

Fazio, A.R.

2004-01-01

In the framework of the formalism of Cornwall et.al. for composite operators I study the ghost-antighost condensation in SU(2) Yang-Mills theories quantized in the Maximal Abelian Gauge and derive analytically a condensating effective potential at two ghost loops. I find that in this approximation the one-loop pairing ghost-antighost is not destroyed and no mass is generated if the ansatz for the propagator suggested by the tree level Hubbard-Stratonovich transformations is used

Series expansions of the density of states in SU(2) lattice gauge theory

International Nuclear Information System (INIS)

Denbleyker, A.; Du, Daping; Liu, Yuzhi; Meurice, Y.; Velytsky, A.

2008-01-01

We calculate numerically the density of states n(S) for SU(2) lattice gauge theory on L 4 lattices [S is the Wilson's action and n(S) measures the relative number of ways S can be obtained]. Small volume dependences are resolved for small values of S. We compare ln(n(S)) with weak and strong coupling expansions. Intermediate order expansions show a good overlap for values of S corresponding to the crossover. We relate the convergence of these expansions to those of the average plaquette. We show that, when known logarithmic singularities are subtracted from ln(n(S)), expansions in Legendre polynomials appear to converge and could be suitable to determine the Fisher's zeros of the partition function.

Scaling of the quark-antiquark potential and improved actions in SU(2) lattice gauge theory

International Nuclear Information System (INIS)

Montvay, I.; Gutbrod, F.

1983-11-01

The scaling behaviour of the quark-antiquark potential is investigated by a high statistics Monte Carlo calculation in SU(2) lattice gauge theory. Besides the standard one-plaquette action we also use Symanzik's tree-level improved action and Wilson's block-spin improved action. No significant differences between Symanzik's action and the standard action have been observed. For small β Wilson's action scales differently. The string tension value chi extracted from the data corresponds to Λsub(latt) = (0.018 +- 0.001) √chi for the one-plaquette action. (orig.)

SU(5)c color model constraints from UA2

International Nuclear Information System (INIS)

Foot, R.; Hernandez, O.F.; Rizzo, T.G.; Ames Lab., IA; Iowa State Univ. of Science and Technology, Ames

1991-01-01

We investigate the possibility that the color gauge group SU(3) may arise as a consequence of the spontaneous symmetry breaking of SU(5) c . In an earlier paper we examine the constraints imposed on the SU(5) c color model by recent measurements of the dijet mass distribution at CDF. We found that the CDF data did not exclude any region of parameter space in the model. Here we consider similar data from UA2 and find that it leads to the constraint Msub(Z') > or approx. 280 GeV. (orig.)

Towards a coupled-cluster treatment of SU(N) lattice gauge field theory

NARCIS (Netherlands)

Bishop, Raymond F.; Ligterink, N.E.; Walet, Niels R.

2006-01-01

A consistent approach to Hamiltonian SU(N) lattice gauge field theory is developed using the maximal-tree gauge and an appropriately chosen set of angular variables. The various constraints are carefully discussed, as is a practical means for their implementation. A complete set of variables for the

Combined study of the gluon and ghost condensates μ2> and abccbcc> in Euclidean SU(2) Yang-Mills theory in the Landau gauge

International Nuclear Information System (INIS)

Capri, M.A.L.; Lemes, V.E.R.; Sobreiro, R.F.; Sorella, S.P.; Dudal, D.; Verschelde, H.; Gracey, J.A.

2006-01-01

The ghost condensate abc c b c c > is considered together with the gluon condensate μ 2 > in SU(2) Euclidean Yang-Mills theories quantized in the Landau gauge. The vacuum polarization ceases to be transverse due to the nonvanishing condensate abc c b c c >. The gluon propagator itself remains transverse. By polarization effects, this ghost condensate induces then a splitting in the gluon mass parameter, which is dynamically generated through μ 2 >. The obtained effective masses are real when μ 2 > is included in the analysis. In the absence of μ 2 >, the already known result that the ghost condensate induces effective tachyonic masses is recovered. At the one-loop level, we find that the effective diagonal mass becomes smaller than the off-diagonal one. This might serve as an indication for some kind of Abelian dominance in the Landau gauge, similar to what happens in the maximal Abelian gauge

Variational estimate of the vacuum state of the SU(2) lattice gauge theory with a disordered trial wave function

International Nuclear Information System (INIS)

Heys, D.W.; Stump, D.R.

1984-01-01

The variational principle is used to estimate the ground state of the Kogut-Susskind Hamiltonian of the SU(2) lattice gauge theory, with a trial wave function for which the magnetic fields on different plaquettes are uncorrelated. This trial function describes a disordered state. The energy expectation value is evaluated by a Monte Carlo method. The variational results are compared to similar results for a related Abelian gauge theory. Also, the expectation value of the Wilson loop operator is computed for the trial state, and the resulting estimate of the string tension is compared to the prediction of asymptotic freedom

Rho meson decay width in SU(2) gauge theories with 2 fundamental flavours

CERN Document Server

Janowski, Tadeusz; Pica, Claudio

2016-01-01

SU(2) gauge theories with two quark flavours in the fundamental representation are among the most promising theories of composite dynamics describing the electroweak sector. Three out of five Goldstone bosons in these models become the longitudinal components of the W and Z bosons giving them mass. Like in QCD, we expect a spectrum of excitations which appear as resonances in vector boson scattering, in particular the vector resonance corresponding to the rho-meson in QCD. In this talk I will present the preliminary results of the first calculation of the rho-meson decay width in this theory, which is analogous to rho to two pions decay calculation in QCD. The results presented were calculated in a moving frame with total momentum (0,0,1) on two ensembles. Future plans include using 3 moving frames on a larger set of ensembles to extract the resonance parameters more reliably and also take the chiral and continuum limits.

Towards the five-loop beta function for a general gauge group

International Nuclear Information System (INIS)

Luthe, Thomas; Schroeder, York

2016-06-01

We present analytical results for the N"4_f and N"3_f terms of the five-loop beta function, for a general gauge group. While the former term agrees with results available from large-N_f studies, the latter is new and extends the value known for SU(3) from an independent calculation.

Topological fluctuations in SU(2) gauge theory with staggered fermions: An exploratory study

International Nuclear Information System (INIS)

Kogut, J.B.; Sinclair, D.K.; Teper, M.; Oxford Univ.

1991-01-01

We investigate some basic aspects of topological fluctuations in lattice QCD, in the version with two colours and four light flavours; and we do so in both the confining, chiral symmetry broken phase in the non-confining, chirally symmetric phase. This latter phase is found to occur not only at high temperatures, just as in the pure gauge system, but also in small spatial volumes, which is unlike the pure gauge case. We derive the way the topological susceptibility should vary with quark mass at small quark masses. We find that the calculated topological susceptibility decreases to zero with the quark mass, with the theoretically expected powers except - in the symmetric phase - at the very smallest values of the quark mass. We demonstrate that this anomalous behaviour can be understood as arising from the fact that the lattice topological 'zero modes' are in fact sufficiently far from being zero. We also show, in the chirally symmetric phase, that, just as expected, the average distance between instantons and anti-instantons decreases with decreasing quark mass. We finish with a new and more precise estimate of the location of the finite-temperature transition in SU(2) with four light flavours. (orig.)

On gauged Baryon and Lepton numbers

International Nuclear Information System (INIS)

Rajpoot, S.

1990-01-01

The observation that Baryon number and Lepton number are conserved in nature provides strong motivation for associating gauge symmetries to these conserved numbers. This endeavor requires that the gauge group of electroweak interactions be extended from SU(2) L X U(1) Y to SU(2) L X U(1) R X U(1) Lepton where U(1) R couples only to the right-handed quarks and leptons. If it furthur postulated that right-handed currents exist on par with the left-handed ones, then the full electroweak symmetry is SU(2) L X SU(2) R X U(1) Baryon X U(1) Lepton . The SU(2) L X SU(2) R X U(1) Baryon X U(1) Lepton model is described in some detail. The triangle anomalies of the three families of quarks and leptons in the model are cancelled invoking leptoquark matter which is new fermionic matter that carries baryon as well as lepton numbers. In addition to the standard neutral boson (Z degree), the theory predicts two neutral gauge bosons with mass lower bounds of 120 GeV and 210 GeV which makes these particles prospective candidates for production at LEP, the TEVATRON and the SSC

On classical solutions of SU(3) gauge field equations

International Nuclear Information System (INIS)

Chakrabarti, A.

1975-01-01

Static classical solutions of SU(3) gauge field equations are studied. The roles of the O(3) subgroup and of the quadrupole generators are discussed systematically. The general form thus obtained leads, through-out, to a high degree of symmetry in the results. This brings in some simplifying features. An octet of scalar mesons is finally added. Certain classes of exact solutions are given that are singular at the origin. A generalized gauge condition is pointed out. The relation of the general form to known particular cases is discussed [fr

Hidden QCD in Chiral Gauge Theories

DEFF Research Database (Denmark)

Ryttov, Thomas; Sannino, Francesco

2005-01-01

The 't Hooft and Corrigan-Ramond limits of massless one-flavor QCD consider the two Weyl fermions to be respectively in the fundamental representation or the two index antisymmetric representation of the gauge group. We introduce a limit in which one of the two Weyl fermions is in the fundamental...... representation and the other in the two index antisymmetric representation of a generic SU(N) gauge group. This theory is chiral and to avoid gauge anomalies a more complicated chiral theory is needed. This is the generalized Georgi-Glashow model with one vector like fermion. We show that there is an interesting...... phase in which the considered chiral gauge theory, for any N, Higgses via a bilinear condensate: The gauge interactions break spontaneously to ordinary massless one-flavor SU(3) QCD. The additional elementary fermionic matter is uncharged under this SU(3) gauge theory. It is also seen that when...

Monte Carlo analysis of the SU(2)xU(1) and U(2) lattice gauge theories at different space-time dimensionalities

International Nuclear Information System (INIS)

Baig, M.; Colet, J.

1986-01-01

Using Monte Carlo simulations the SU(2)xU(1) lattice gauge theory has been analyzed, which is equivalent for the Wilson action to a U(2) theory, at space-time dimensionalities from d=3 to 5. It has been shown that there exist first-order phase transitions for both d=4 and d=5. A monopole-condensation mechanism seems to be responsible for these phase transitions. At d=3 no phase transitions have been detected. (orig.)

Exceptional thermodynamics. The equation of state of G{sub 2} gauge theory

Energy Technology Data Exchange (ETDEWEB)

Bruno, Mattia [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Caselle, Michele [Torino Univ. (Italy). Dipt. di Fisica Teorica; INFN, Sezione di Torino (Italy); Panero, Marco [Univ. Autonoma de Madrid (Spain). Inst. de Fisica Teorica; Consejo Superior de Investigaciones Cientificas, Madrid (Spain); Pellegrini, Roberto [Swansea Univ. (United Kingdom). Dept. of Physics

2014-10-15

We present a lattice study of the equation of state in Yang-Mills theory based on the exceptional G{sub 2} gauge group. As is well-known, at zero temperature this theory shares many qualitative features with real-world QCD, including the absence of colored states in the spectrum and dynamical string breaking at large distances. In agreement with previous works, we show that at finite temperature this theory features a first-order deconfining phase transition, whose nature can be studied by a semi-classical computation. We also show that the equilibrium thermodynamic observables in the deconfined phase bear striking quantitative similarities with those found in SU(N) gauge theories: in particular, these quantities exhibit nearly perfect proportionality to the number of gluon degrees of freedom, and the trace anomaly reveals a characteristic quadratic dependence on the temperature, also observed in SU(N) Yang-Mills theories (both in four and in three spacetime dimensions). We compare our lattice data with analytical predictions from effective models, and discuss their implications for the deconfinement mechanism and high-temperature properties of strongly interacting, non-supersymmetric gauge theories. Our results give strong evidence for the conjecture that the thermal deconfining transition is governed by a universal mechanism, common to all simple gauge groups.

Genetic algorithm for lattice gauge theory on SU(2) and U(1) on 4 dimensional lattice, how to hitchhike to thermal equilibrium state

International Nuclear Information System (INIS)

Yamaguchi, A.; Sugamoto, A.

2000-01-01

Applying Genetic Algorithm for the Lattice Gauge Theory is formed to be an effective method to minimize the action of gauge field on a lattice. In 4 dimensions, the critical point and the Wilson loop behaviour of SU(2) lattice gauge theory as well as the phase transition of U(1) theory have been studied. The proper coding methodi has been developed in order to avoid the increase of necessary memory and the overload of calculation for Genetic Algorithm. How hichhikers toward equilibrium appear against kidnappers is clarified

Deconfinement on ℝ2×SL1×Sβ1 for all gauge groups and duality to double Coulomb gas

International Nuclear Information System (INIS)

Teeple, Brett

2016-01-01

I study finite-temperature N=1 super Yang-Mills for any gauge group G=A N ,B N ,C N ,D N ,E 6,7,8 ,F 4 ,G 2 , compactified from four dimensions on a torus, ℝ 2 ×S L 1 ×S β 1 . I examine in particular the low temperature regime L≪β=1/T, where L is the length of the spatial circle with periodic boundary conditions and with anti-periodic boundary conditions for the adjoint gauginos along the thermal cycle S β 1 . For small such L we are in a regime were semiclassical calculations can be performed and a transition occurs at T c much smaller than 1/NL. The transition is mediated by the competition between non-perturbative objects including ‘exotic’ topological molecules: neutral and magnetic bions composed of BPS and KK monopole constituents, with r=rank(G) different charges in the co-root lattice of the gauge group G, and the perturbative electrically charged W-bosons (along with their wino superpartners). The difference from non-SUSY theories here is that the Higgsing along the thermal cycle gives rise to a light modulus scalar field which couples to both bion-instantons and the W-bosons, and mediates a transition near T c where the bions and W-bosons compete with equal strengths. The transition is seen to be similar to previous studies on ℝ 3 ×S L 1 http://dx.doi.org/10.1007/JHEP11(2013)142; http://dx.doi.org/10.1007/JHEP09(2014)040; http://dx.doi.org/10.1007/JHEP03(2013)087; http://dx.doi.org/10.1007/JHEP09(2013)128 with general gauge group where a first order transition was found for all groups, but a second order one for the case of SU(2) on the torus ℝ 2 ×S L 1 ×S β 1 , which was subjected to lattice studies in http://dx.doi.org/10.1007/JHEP11(2013)142. I determine a duality to a double Coulomb gas of neutral and magnetic bions of different charges of their constituent monopole-instantons, and W-bosons of both scalar and electric charges. Aharanov-Bohm interactions exist between magnetic bions and W-bosons, and scalar charges of W-bosons and

Deconfinement at the Argyres-Douglas point in SU(2) gauge theory with broken N=2 supersymmetry

International Nuclear Information System (INIS)

Gorsky, A.; Vainshtein, A.; Yung, A.

2000-01-01

We consider chiral condensates in SU(2) gauge theory with broken N=2 supersymmetry. The matter sector contains an adjoint multiplet and one fundamental flavor. Matter and gaugino condensates are determined by integrating out the adjoint field. The only nonperturbative input is the Affleck-Dine-Seiberg (ADS) superpotential generated by one instanton plus the Konishi anomaly. These results are consistent with those obtained by the 'integrating in' procedure, including a reproduction of the Seiberg-Witten curve from the ADS superpotential. We then calculate monopole, dyon, and charge condensates using the Seiberg-Witten approach. We show that the monopole and charge condensates vanish at the Argyres-Douglas point where the monopole and charge vacua collide. We interpret this phenomenon as a deconfinement of electric and magnetic charges at the Argyres-Douglas point

IR fixed points in SU(3 gauge theories

Directory of Open Access Journals (Sweden)

K.-I. Ishikawa

2015-09-01

Full Text Available We propose a novel RG method to specify the location of the IR fixed point in lattice gauge theories and apply it to the SU(3 gauge theories with Nf fundamental fermions. It is based on the scaling behavior of the propagator through the RG analysis with a finite IR cutoff, which we cannot remove in the conformal field theories in sharp contrast to the confining theories. The method also enables us to estimate the anomalous mass dimension in the continuum limit at the IR fixed point. We perform the program for Nf=16,12,8 and Nf=7 and indeed identify the location of the IR fixed points in all cases.

Invariant structures in gauge theories and confinement

International Nuclear Information System (INIS)

Prokhorov, L.V.; Shabanov, S.V.

1991-01-01

The problem of finding all gauge invariants is considered in connection with the problem of confinement. Polylocal gauge tensors are introduced and studied. It is shown (both in physical and pure geometrical approaches) that the path-ordered exponent is the only fundamental bilocal gauge tensor, which means that any irreducible polylocal gauge tensor is built of P-exponents and local tensors (matter fields). The simplest invariant structures in electrodynamics, chromodynamics and a theory with the gauge group SU(2) are considered separately. 23 refs.; 2 figs

Threshold corrections and gauge symmetry in twisted superstring models

International Nuclear Information System (INIS)

Pierce, D.M.

1994-01-01

Threshold corrections to the running of gauge couplings are calculated for superstring models with free complex world sheet fermions. For two N=1 SU(2)xU(1) 5 models, the threshold corrections lead to a small increase in the unification scale. Examples are given to illustrate how a given particle spectrum can be described by models with different boundary conditions on the internal fermions. We also discuss how complex twisted fermions can enhance the symmetry group of an N=4, SU(3)xU(1)xU(1) model to the gauge group SU(3)xSU(2)xU(1). It is then shown how a mixing angle analogous to the Weinberg angle depends on the boundary conditions of the internal fermions

Translational groups as generators of gauge transformations

International Nuclear Information System (INIS)

Scaria, Tomy

2003-01-01

We examine the gauge generating nature of the translational subgroup of Wigner's little group for the case of massless tensor gauge theories and show that the gauge transformations generated by the translational group are only a subset of the complete set of gauge transformations. We also show that, just as in the case of topologically massive gauge theories, translational groups act as generators of gauge transformations in gauge theories obtained by extending massive gauge noninvariant theories by a Stueckelberg mechanism. The representations of the translational groups that generate gauge transformations in such Stueckelberg extended theories can be obtained by the method of dimensional descent. We illustrate these results with the examples of Stueckelberg extended first class versions of Proca, Einstein-Pauli-Fierz, and massive Kalb-Ramond theories in 3+1 dimensions. A detailed analysis of the partial gauge generation in massive and massless second rank symmetric gauge theories is provided. The gauge transformations generated by the translational group in two-form gauge theories are shown to explicitly manifest the reducibility of gauge transformations in these theories

Translational groups as generators of gauge transformations

Science.gov (United States)

Scaria, Tomy

2003-11-01

We examine the gauge generating nature of the translational subgroup of Wigner’s little group for the case of massless tensor gauge theories and show that the gauge transformations generated by the translational group are only a subset of the complete set of gauge transformations. We also show that, just as in the case of topologically massive gauge theories, translational groups act as generators of gauge transformations in gauge theories obtained by extending massive gauge noninvariant theories by a Stückelberg mechanism. The representations of the translational groups that generate gauge transformations in such Stückelberg extended theories can be obtained by the method of dimensional descent. We illustrate these results with the examples of Stückelberg extended first class versions of Proca, Einstein-Pauli-Fierz, and massive Kalb-Ramond theories in 3+1 dimensions. A detailed analysis of the partial gauge generation in massive and massless second rank symmetric gauge theories is provided. The gauge transformations generated by the translational group in two-form gauge theories are shown to explicitly manifest the reducibility of gauge transformations in these theories.

Pure classical SU(2) Yang-Mills theory with potentials invariant under a U(1) gauge subgroup

International Nuclear Information System (INIS)

Bacry, H.

1978-07-01

The present article is devoted to pure SU(2) classical Yang-Mills theories whose potentials are invariant under a U(1) gauge subgroup. Such potentials are shown to be associated with classical Maxwell-like fields with magnetic sources as 't Hooft's monopole is associated with the Dirac magnetic monopole. Conversely, the authors give Yang-Mills potentials corresponding to some Maxwell-like fields, in particular static magnetic fields with emphasis on those with cylindrical symmetry (including the dipole and other multipoles) and the ephemerons corresponding to an instantaneous magnetic multipole

Integrability in N=2 superconformal gauge theorie

Energy Technology Data Exchange (ETDEWEB)

Pomoni, Elli [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany). Theory Group; National Technical Univ. of Athens (Greece). Physics Div.

2013-10-15

Any N=2 superconformal gauge theory (including N=4 SYM) contains a set of local operators made only out of fields in the N=2 vector multiplet that is closed under renormalization to all loops, namely the SU(2,1 vertical stroke 2) sector. For planar N=4 SYM the spectrum of local operators can be obtained by mapping the problem to an integrable model (a spin chain in perturbation theory), in principle for any value of the coupling constant. We present a diagrammatic argument that for any planar N=2 superconformal gauge theory the SU(2,1 vertical stroke 2) Hamiltonian acting on infinite spin chains is identical to all loops to that of N=4 SYM, up to a redefinition of the coupling constant. Thus, this sector is integrable and anomalous dimensions can be, in principle, read off from the N=4 ones up to this redefinition.

Integrability in N=2 superconformal gauge theories

International Nuclear Information System (INIS)

Pomoni, Elli; National Technical Univ. of Athens

2013-10-01

Any N=2 superconformal gauge theory (including N=4 SYM) contains a set of local operators made only out of fields in the N=2 vector multiplet that is closed under renormalization to all loops, namely the SU(2,1 vertical stroke 2) sector. For planar N=4 SYM the spectrum of local operators can be obtained by mapping the problem to an integrable model (a spin chain in perturbation theory), in principle for any value of the coupling constant. We present a diagrammatic argument that for any planar N=2 superconformal gauge theory the SU(2,1 vertical stroke 2) Hamiltonian acting on infinite spin chains is identical to all loops to that of N=4 SYM, up to a redefinition of the coupling constant. Thus, this sector is integrable and anomalous dimensions can be, in principle, read off from the N=4 ones up to this redefinition.

SU (2) with fundamental fermions and scalars

DEFF Research Database (Denmark)

Hansen, Martin; Janowski, Tadeusz; Pica, Claudio

2018-01-01

We present preliminary results on the lattice simulation of an SU(2) gauge theory with two fermion flavors and one strongly interacting scalar field, all in the fundamental representation of SU(2). The motivation for this study comes from the recent proposal of "fundamental" partial compositeness...... the properties of light meson resonances previously obtained for the SU(2) model. Preprint: CP3-Origins-2017-047 DNRF90...

Three-Index Symmetric Matter Representations of SU(2) in F-Theory from Non-Tate Form Weierstrass Models

CERN Document Server

Klevers, Denis

2016-01-01

We give an explicit construction of a class of F-theory models with matter in the three-index symmetric (4) representation of SU(2). This matter is realized at codimension two loci in the F-theory base where the divisor carrying the gauge group is singular; the associated Weierstrass model does not have the form associated with a generic SU(2) Tate model. For 6D theories, the matter is localized at a triple point singularity of arithmetic genus g=3 in the curve supporting the SU(2) group. This is the first explicit realization of matter in F-theory in a representation corresponding to a genus contribution greater than one. The construction is realized by "unHiggsing" a model with a U(1) gauge factor under which there is matter with charge q=3. The resulting SU(2) models can be further unHiggsed to realize non-Abelian G_2xSU(2) models with more conventional matter content or SU(2)^3 models with trifundamental matter. The U(1) models used as the basis for this construction do not seem to have a Weierstrass real...

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)

Correlation functions of the energy-momentum tensor in SU(2) gauge theory at finite temperature

DEFF Research Database (Denmark)

Huebner, K.; Karsch, F.; Pica, Claudio

2008-01-01

We calculate correlation functions of the energy-momentum tensor in the vicinity of the deconfinement phase transition of (3+1)-dimensional SU(2) gauge theory and discuss their critical behavior in the vicinity of the second order deconfinement transition. We show that correlation functions...... of the trace of the energy momentum tensor diverge uniformly at the critical point in proportion to the specific heat singularity. Correlation functions of the pressure, on the other hand, stay finite at the critical point. We discuss the consequences of these findings for the analysis of transport...... coefficients, in particular the bulk viscosity, in the vicinity of a second order phase transition point....

Domain walls and perturbation theory in high-temperature gauge theory: SU(2) in 2+1 dimensions

International Nuclear Information System (INIS)

Korthals Altes, C.; Michels, A.; Teper, M.; Stephanov, M.

1997-01-01

We study the detailed properties of Z 2 domain walls in the deconfined high-temperature phase of the d=2+1 SU(2) gauge theory. These walls are studied both by computer simulations of the lattice theory and by one-loop perturbative calculations. The latter are carried out both in the continuum and on the lattice. We find that leading order perturbation theory reproduces the detailed properties of these domain walls remarkably accurately even at temperatures where the effective dimensionless expansion parameter g 2 /T is close to unity. The quantities studied include the surface tension, the action density profiles, roughening, and the electric screening mass. It is only for the last quantity that we find an exception to the precocious success of perturbation theory. All this shows that, despite the presence of infrared divergences at higher orders, high-T perturbation theory can be an accurate calculational tool. copyright 1997 The American Physical Society

Two-dimensional N=(2,2) lattice gauge theories with matter in higher representations

International Nuclear Information System (INIS)

Joseph, Anosh

2014-06-01

We construct two-dimensional N=(2,2) supersymmetric gauge theories on a Euclidean spacetime lattice with matter in the two-index symmetric and anti-symmetric representations of SU(N c ) color group. These lattice theories preserve a subset of the supercharges exact at finite lattice spacing. The method of topological twisting is used to construct such theories in the continuum and then the geometric discretization scheme is used to formulate them on the lattice. The lattice theories obtained this way are gauge-invariant, free from fermion doubling problem and exact supersymmetric at finite lattice spacing. We hope that these lattice constructions further motivate the nonperturbative explorations of models inspired by technicolor, orbifolding and orientifolding in string theories and the Corrigan-Ramond limit.

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.)

The standard model from a gauge theory in ten dimensions via CSDR

International Nuclear Information System (INIS)

Farakos, K.; Kapetanakis, D.; Koutsoumbas, G.; Zoupanos, G.

1988-01-01

We present a gauge theory in ten dimensions based on the gauge group E 8 which is dimensionally reduced, according to the coset space dimensional reduction (CSDR) scheme, to the standard model SU 3c xSU 2L xU 1 , which breaks further to SU 3c xU 1em . We use the coset space Sp 4 /(SU 2 xU 1 )xZ 2 . The model gives similar predictions for sin 2 θ w and proton decay as the minimal SU 5 GUT. Natural choices of parameters suggest that the Higgs masses are as predicted by the Coleman-Weinberg radiative mechanism. (orig.)

Standard model from a gauge theory in ten dimensions via CSDR

Energy Technology Data Exchange (ETDEWEB)

Farakos, K.; Kapetanakis, D.; Koutsoumbas, G.; Zoupanos, G.

1988-09-01

We present a gauge theory in ten dimensions based on the gauge group E/sub 8/ which is dimensionally reduced, according to the coset space dimensional reduction (CSDR) scheme, to the standard model SU/sub 3c/xSU/sub 2L/xU/sub 1/, which breaks further to SU/sub 3c/xU/sub 1em/. We use the coset space Sp/sub 4//(SU/sub 2/xU/sub 1/)xZ/sub 2/. The model gives similar predictions for sin /sup 2/theta/sub w/ and proton decay as the minimal SU/sub 5/ GUT. Natural choices of parameters suggest that the Higgs masses are as predicted by the Coleman-Weinberg radiative mechanism.

Instantons and Gribov copies in the maximally Abelian gauge

International Nuclear Information System (INIS)

Bruckmann, F.; Heinzl, T.; Wipf, A.; Tok, T.

2000-01-01

We calculate the Faddeev-Popov operator corresponding to the maximally Abelian gauge for gauge group SU(N). Specializing to SU(2) we look for explicit zero modes of this operator. Within an illuminating toy model (Yang-Mills mechanics) the problem can be completely solved and understood. In the field theory case we are able to find an analytic expression for a normalizable zero mode in the background of a single 't Hooft instanton. Accordingly, such an instanton corresponds to a horizon configuration in the maximally Abelian gauge. Possible physical implications are discussed

Gauge-invariant formulation of SU(2) gluodynamics

International Nuclear Information System (INIS)

Simonov, Yu.A.

1984-01-01

The internal structure of a double asymmetric rotator is revealed in vector potential Asub(μa) via a proposed polar representation (PR). In the functional integral a natural gauge choice exists in PR not accompanied by Faddeev-Popov ghosts and Gribov ambiguities. Classical equations in PR are written in terms of only gauge invariant quantities. Instantons and magnetic monopoles in the Bogolmolny-Prasad-Sommerfield limit as well as the color-magnetic field of the 'tHooft-Polyakov monopole are studied in PR

Unitary Representations of Gauge Groups

Science.gov (United States)

Huerfano, Ruth Stella

I generalize to the case of gauge groups over non-trivial principal bundles representations that I. M. Gelfand, M. I. Graev and A. M. Versik constructed for current groups. The gauge group of the principal G-bundle P over M, (G a Lie group with an euclidean structure, M a compact, connected and oriented manifold), as the smooth sections of the associated group bundle is presented and studied in chapter I. Chapter II describes the symmetric algebra associated to a Hilbert space, its Hilbert structure, a convenient exponential and a total set that later play a key role in the construction of the representation. Chapter III is concerned with the calculus needed to make the space of Lie algebra valued 1-forms a Gaussian L^2-space. This is accomplished by studying general projective systems of finitely measurable spaces and the corresponding systems of sigma -additive measures, all of these leading to the description of a promeasure, a concept modeled after Bourbaki and classical measure theory. In the case of a locally convex vector space E, the corresponding Fourier transform, family of characters and the existence of a promeasure for every quadratic form on E^' are established, so the Gaussian L^2-space associated to a real Hilbert space is constructed. Chapter III finishes by exhibiting the explicit Hilbert space isomorphism between the Gaussian L ^2-space associated to a real Hilbert space and the complexification of its symmetric algebra. In chapter IV taking as a Hilbert space H the L^2-space of the Lie algebra valued 1-forms on P, the gauge group acts on the motion group of H defining in an straight forward fashion the representation desired.

Efficient multitasking of the SU(3) lattice gauge theory algorithm on the CRAY X-MP

International Nuclear Information System (INIS)

Kuba, D.W.; Moriarty, K.J.M.

1985-01-01

The Monte Carlo lattice gauge theory algorithm with the Metropolis et.al. updating procedure is vectorized and multitasked on the four processor CRAY X-MP and results in a code with a link-update-time, in 64-bit arithmetic and 10 hits-per-link, of 11.0 μs on a 16 4 lattice, the fastest link-update-time so far achieved. The program calculates the Wilson loops of size up to L/2.L/2 for an L 4 lattice for SU(3) gauge theory. (orig./HSI)

Gluon condensate from lattice caculations: SU(3) pure gauge theory

International Nuclear Information System (INIS)

Kripfganz, J.

1981-01-01

A short distance expansion of Wilson loops is used to define and isolate vacuum expectation values of composite gluon operators. It is applied to available lattice Monte Carlo data for SU(3) pure gauge theory. The value obtained for the gluon condensate is consistent with the ITEP estimate. (author)

Surface representations of Wilson loop expectations in lattice gauge theory

International Nuclear Information System (INIS)

Brydges, D.C.; Giffen, C.; Durhuus, B.; Froehlich, J.

1986-01-01

Expectations of Wilson loops in lattice gauge theory with gauge group G=Z 2 , U(1) or SU(2) are expressed as weighted sums over surfaces with boundary equal to the loops labelling the observables. For G=Z 2 and U(1), the weights are all positive. For G=SU(2), the weights can have either sign depending on the Euler characteristic of the surface. Our surface (or flux sheet-) representations are partial resummations of the strong coupling expansion and provide some qualitative understanding of confinement. The significance of flux sheets with nontrivial topology for permanent confinement in the SU(2)-theory is elucidated. (orig.)

Gauge glass

International Nuclear Information System (INIS)

Nielsen, H.B.; Brene, N.

1984-12-01

The fundamental laws of nature may be truely random, or they may be so complicated that a random description is adequate. With this philosophy we examine various ways in which a lattice gauge theory (at the Planck scale) can be generalized. Without here giving up a regular lattice structure (which we really ought to do) we consider two generalizations. Making the action (quenched) random has the effect that the gauge group tends to break down and some gauge bosons become massive, unless the gauge group has special properties: no noncentral corners in the geometry of conjugacy classes and furthermore a connected center. Making the concept of gauge transformation more general has a symmetry breaking effect for groups with outer automorphisms. A study of SU 5 -breaking in the context of the first breakdown mechanism (D. Bennett, E. Buturovic and H. B. Nielsen) is shortly reviewed. (orig.)

Gauging the graded conformal group with unitary internal symmetries

International Nuclear Information System (INIS)

Ferrara, S.; Townsend, P.K.; Kaku, M.; Nieuwenhuizen Van, P.

1977-06-01

Gauge theories for extended SU(N) conformal supergravity are constructed which are invariant under local scale, chiral, proper conformal, supersymmetry and internal SU(N) transformations. The relation between intrinsic parity and symmetry properties of their generators of the internal vector mesons is established. These theories contain no cosmological constants, but technical problems inherent to higher derivative actions are pointed out

Group theory and lattice gauge fields

International Nuclear Information System (INIS)

Creutz, M.

1988-09-01

Lattice gauge theory, formulated in terms of invariant integrals over group elements on lattice bonds, benefits from many group theoretical notions. Gauge invariance provides an enormous symmetry and powerful constraints on expectation values. Strong coupling expansions require invariant integrals over polynomials in group elements, all of which can be evaluated by symmetry considerations. Numerical simulations involve random walks over the group. These walks automatically generate the invariant group measure, avoiding explicit parameterization. A recently proposed overrelaxation algorithm is particularly efficient at exploring the group manifold. These and other applications of group theory to lattice gauge fields are reviewed in this talk. 17 refs

Conversed, gauge-covariant colour charge in Su(n)QCD

International Nuclear Information System (INIS)

Selikhov, A.V.

1988-01-01

The definition of the integral of the group tensor and the gauge-covariant differential with respect to a distant point are given in the work. A conserved covariant charge dependence on family of paths has been contracted with the help of these notions. It has been shown that the same family of paths fixes a gauge in which the covariant and noncovariant conserved currents coicide. The gauge is characterized by representation of the vector potential via field strength tensor. The possibility of connecting the choice of the family of paths with the measurement procedure is discussed. 13 refs.; 2 figs

Classical local U(1 gauge invariance in Weyl 2-spinor lenguage and charge quantization from irreducible representations of the gauge group

Directory of Open Access Journals (Sweden)

J. Buitrago

Full Text Available A new classical 2-spinor approach to U(1 gauge theory is presented in which the usual four-potential vector field is replaced by a symmetric second rank spinor. Following a lagrangian formulation, it is shown that the four-rank spinor representing the Maxwell field tensor has a U(1 local gauge invariance in terms of the electric and magnetic field strengths. When applied to the magnetic field of a monopole, this formulation, via the irreducible representation condition for the gauge group, leads to a quantization condition differing by a factor 2 of the one predicted by Dirac without relying on any kind of singular vector potentials. Finally, the U(1 invariant spinor equations, are applied to electron magnetic resonance which has many applications in the study of materials. Keywords: Weyl 2-spinor lenguage, Dirac equation, Gauge theories, Charge quantization

A gauge model with eight quarks

International Nuclear Information System (INIS)

Ragiadakos, C.

1977-01-01

A gauge model with eight quarks, on the basis of the SU(2)U(1) gauge group, containing the Weinberg-Salam-GIM model is proposed. It may explain the ratio of the neutral current and charged current found at Gargamelle and HPWF, the large y anomaly and, with a convenient introduction of the leptonic sector, the energetic trimuons observed recently in neutrino nucleon collisions

Instantons, three-dimensional gauge theory, and the Atiyah-Hitchin manifold

NARCIS (Netherlands)

Dorey, N.; Khoze, V.V.; Mattis, M.P.; Tong, D.; Vandoren, S.

1997-01-01

We investigate quantum effects on the Coulomb branch of three-dimensional N = 4 supersymmetric gauge theory with gauge group SU(2). We calculate perturbative and one-instanton contributions to the Wilsonian effective action using standard weakcoupling methods. Unlike the four-dimensional case,

Direct gauging of the Poincare group V. Group scaling, classical gauge theory, and gravitational corrections

International Nuclear Information System (INIS)

Edelen, D.G.B.

1986-01-01

Homogeneous scaling of the group space of the Poincare group, P 10 , is shown to induce scalings of all geometric quantities associated with the local action of P 10 . The field equations for both the translation and the Lorentz rotation compensating fields reduce to O(1) equations if the scaling parameter is set equal to the general relativistic gravitational coupling constant 8πGc -4 . Standard expansions of all field variables in power series in the scaling parameter give the following results. The zeroth-order field equations are exactly the classical field equations for matter fields on Minkowski space subject to local action of an internal symmetry group (classical gauge theory). The expansion process is shown to break P 10 -gauge covariance of the theory, and hence solving the zeroth-order field equations imposes an implicit system of P 10 -gauge conditions. Explicit systems of field equations are obtained for the first- and higher-order approximations. The first-order translation field equations are driven by the momentum-energy tensor of the matter and internal compensating fields in the zeroth order (classical gauge theory), while the first-order Lorentz rotation field equations are driven by the spin currents of the same classical gauge theory. Field equations for the first-order gravitational corrections to the matter fields and the gauge fields for the internal symmetry group are obtained. Direct Poincare gauge theory is thus shown to satisfy the first two of the three-part acid test of any unified field theory. Satisfaction of the third part of the test, at least for finite neighborhoods, seems probable

Spin Gauge Theory of Gravity in Clifford Space

International Nuclear Information System (INIS)

Pavsic, Matej

2006-01-01

A theory in which 16-dimensional curved Clifford space (C-space) provides a realization of Kaluza-Klein theory is investigated. No extra dimensions of spacetime are needed: 'extra dimensions' are in C-space. We explore the spin gauge theory in C-space and show that the generalized spin connection contains the usual 4-dimensional gravity and Yang-Mills fields of the U(1) x SU(2) x SU(3) gauge group. The representation space for the latter group is provided by 16-component generalized spinors composed of four usual 4-component spinors, defined geometrically as the members of four independent minimal left ideals of Clifford algebra

Dark matter model with non-Abelian gauge symmetry

International Nuclear Information System (INIS)

Zhang Hao; Li Chongsheng; Cao Qinghong; Li Zhao

2010-01-01

We propose a dark-matter model in which the dark sector is gauged under a new SU(2) group. The dark sector consists of SU(2) dark gauge fields, two triplet dark Higgs fields, and two dark fermion doublets (dark-matter candidates in this model). The dark sector interacts with the standard model sector through kinetic and mass mixing operators. The model explains both PAMELA and Fermi LAT data very well and also satisfies constraints from both the dark-matter relic density and standard model precision observables. The phenomenology of the model at the LHC is also explored.

Study of the maximal Abelian gauge in SU(2) Euclidean Yang-Mills theory in the presence of the Gribov horizon

International Nuclear Information System (INIS)

Capri, M. A. L.; Lemes, V. E. R.; Sobreiro, R. F.; Sorella, S. P.; Thibes, R.

2006-01-01

We pursue the study of SU(2) Euclidean Yang-Mills theory in the maximal Abelian gauge by taking into account the effects of the Gribov horizon. The Gribov approximation, previously introduced in [M. A. L. Capri, V. E. R. Lemes, R. F. Sobreiro, S. P. Sorella, and R. Thibes, Phys. Rev. D 72, 085021 (2005).], is improved through the introduction of the horizon function, which is constructed under the requirements of localizability and renormalizability. By following Zwanziger's treatment of the horizon function in the Landau gauge, we prove that, when cast in local form, the horizon term of the maximal Abelian gauge leads to a quantized theory which enjoys multiplicative renormalizability, a feature which is established to all orders by means of the algebraic renormalization. Furthermore, it turns out that the horizon term is compatible with the local residual U(1) Ward identity, typical of the maximal Abelian gauge, which is easily derived. As a consequence, the nonrenormalization theorem, Z g Z A 1/2 =1, relating the renormalization factors of the gauge coupling constant Z g and of the diagonal gluon field Z A , still holds in the presence of the Gribov horizon. Finally, we notice that a generalized dimension two gluon operator can be also introduced. It is BRST invariant on-shell, a property which ensures its multiplicative renormalizability. Its anomalous dimension is not an independent parameter of the theory, being obtained from the renormalization factors of the gauge coupling constant and of the diagonal antighost field

Witten index calculation in supersymmetric gauge theory

International Nuclear Information System (INIS)

Smilga, A.V.

1984-01-01

Direct calculation of the Witten index Isub(W) in the SU(2) SUSY Yang-Mills theiory is performed using the periodic boundary conditions. Our result is Isub(W)--1 which disagrees with the Witten's result: Isub(W)=N for the SU(N) gauge group. The principle physical conclusion of SUSY unbreaking in this theory remains intact

Abelian color cycles: A new approach to strong coupling expansion and dual representations for non-abelian lattice gauge theory

Energy Technology Data Exchange (ETDEWEB)

Gattringer, Christof, E-mail: christof.gattringer@uni-graz.at; Marchis, Carlotta, E-mail: carla.marchis@uni-graz.at

2017-03-15

We propose a new approach to strong coupling series and dual representations for non-abelian lattice gauge theories using the SU(2) case as an example. The Wilson gauge action is written as a sum over “abelian color cycles” (ACC) which correspond to loops in color space around plaquettes. The ACCs are complex numbers which can be commuted freely such that the strong coupling series and the dual representation can be obtained as in the abelian case. Using a suitable representation of the SU(2) gauge variables we integrate out all original gauge links and identify the constraints for the dual variables in the SU(2) case. We show that the construction can be generalized to the case of SU(2) gauge fields with staggered fermions. The result is a strong coupling series where all gauge integrals are known in closed form and we discuss its applicability for possible dual simulations. The abelian color cycle concept can be generalized to other non-abelian gauge groups such as SU(3).

Lagrangian formulation for a gauge theory of strong and electromagnetic interactions defined on a Cartan bundle

International Nuclear Information System (INIS)

Drechsler, W.

1977-01-01

A Lagrangian formalism invariant under the gauge group U 1 xUSpsub(2.2) is set up in terms of spinor fields defined on a fiber bundle with Cartan connexion. The fiber of the Cartan bundle over space-time associated with strong interactions is characterized by an elementary length parameter R related to the range of the strong forces, and the structural group USpsub(2.2) of the bundle (being the covering group of the SOsub(4.1) de Sitter group) implies a gauge description of strong interactions based on the noncompact gauge group USpsub(2.2). The U 1 factor in the total gauge group corresponds to the usual gauge formulation for the electromagnetic interactions. The positivity of the energy associated with stable extended one-particle states in this dualistic description of charged hadronic matter immersed in the fiber geometry (this dualism is called strong fiber dynamics (SFD)) requires hadrons to be assigned to representations of the compact subgroup SU 2 xSU 2 of the strong-interaction gauge group USpsub(2.2). A brief discussion of the point-particle limit R→O is given by linking the presented SFD formalism for extended hadrons to an idealized description in terms of operators in a local quantum field theory

Electromagnetic mass differences in the SU(3) x U(1) gauge model

International Nuclear Information System (INIS)

Maharana, K.; Sastry, C.V.

1975-01-01

In this note we point out that the electromagnetic mass differences of the pion and kaon in the SU(3) times U(1) model are the same as in Weinberg's model except for the differences in the masses of the gauge bosons

The winding number of three complexes in SU(3)

International Nuclear Information System (INIS)

Lasher, G.

1989-01-01

The Phillip-Stone algorithm for the topological charge of a lattice gauge field requires the computation of the winding number of certain 3-complexes in the space of the group. The extension of the computational procedure for the SU(2) gauge group to SU(3) requires an understanding of the SU(3) geometry. An important issue is the behavior of a 3-cell in SU(3) as it approaches a critical configuration, i.e., one at which the cell is a discontinuous function of its vertices. A measure of the proximity of a cell to criticality is found and a method for computing its contribution to the winding number is recommended. (orig.)

New models of gauge- and gravity-mediated supersymmetry breaking

International Nuclear Information System (INIS)

Poppitz, E.; Trivedi, S.P.

1997-01-01

We show that supersymmetry breaking in a class of theories with SU(N)xSU(N-2) gauge symmetry can be studied in a calculable σ model. We use the σ model to show that the supersymmetry-breaking vacuum in these theories leaves a large subgroup of flavor symmetries intact, and to calculate the masses of the low-lying states. By embedding the standard model gauge groups in the unbroken flavor symmetry group we construct a class of models in which supersymmetry breaking is communicated by both gravitational and gauge interactions. One distinguishing feature of these models is that the messenger fields, responsible for the gauge-mediated communication of supersymmetry breaking, are an integral part of the supersymmetry-breaking sector. We also show how, by lowering the scale that suppresses the nonrenormalizable operators, a class of purely gauge-mediated models with a combined supersymmetry-breaking-cum-messenger sector can be built. We briefly discuss the phenomenological features of the models we construct. copyright 1997 The American Physical Society

Gluon-ghost condensate of mass dimension 2 in the Curci-Ferrari gauge

International Nuclear Information System (INIS)

Dudal, D.; Verschelde, H.; Lemes, V.E.R.; Sarandy, M.S.; Sorella, S.P.; Picariello, M.

2003-01-01

The effective potential for an on-shell BRST invariant gluon-ghost condensate of mass dimension 2 in the Curci-Ferrari gauge in SU(N) Yang-Mills is analysed by combining the local composite operator technique with the algebraic renormalization. We pay attention to the gauge parameter independence of the vacuum energy obtained in the considered framework and discuss the Landau gauge as an interesting special case

The Yang-Mills gradient flow and SU(3) gauge theory with 12 massless fundamental fermions in a colour-twisted box

CERN Document Server

Lin, C -J David; Ramos, Alberto

2015-01-01

We perform the step-scaling investigation of the running coupling constant, using the gradient-flow scheme, in SU(3) gauge theory with twelve massless fermions in the fundamental representation. The Wilson plaquette gauge action and massless unimproved staggered fermions are used in the simulations. Our lattice data are prepared at high accuracy, such that the statistical error for the renormalised coupling, g_GF, is at the subpercentage level. To investigate the reliability of the continuum extrapolation, we employ two different lattice discretisations to obtain g_GF. For our simulation setting, the corresponding gauge-field averaging radius in the gradient flow has to be almost half of the lattice size, in order to have this extrapolation under control. We can determine the renormalisation group evolution of the coupling up to g^2_GF ~ 6, before the onset of the bulk phase structure. In this infrared regime, the running of the coupling is significantly slower than the two-loop perturbative prediction, altho...

Towards a unified picture for gauge and Higgs fields

International Nuclear Information System (INIS)

Mecklenburg, W.

1981-01-01

A scheme for a geometrical unification of gauge and Higgs fields, previously given for SU 2 , is generalized to include arbitrary semisimple gauge groups. Gauge and physical Higgs fields appear as different components of the same tensor in a high dimensional manifold, the higher dimensions being comprised by the group coordinates. Their respective inhomogeneous transformation behaviour is derived from the same principle. The number of Higgs fields is restricted. The form of the Higgs potential is fixed and the mass of the Higgs particle is predicted in terms of the vector boson mass. (author)

Instanton partons in 5-dimensional SU(N) gauge theory

International Nuclear Information System (INIS)

Bolognesi, Stefano; Lee, Kimyeong

2011-01-01

The circle compactification of the 6-dimensional (2,0) superconformal theory of A N-1 type leads to the 5-dimensional SU(N) maximally supersymmetric gauge theory. Instanton solitons embody Kaluza-Klein modes and are conjectured to be composed of partonic constituents. We realize such a parton of 1/N instanton topological charge at the intersection of magnetic flux sheets. After a further compactification with nontrivial Wilson-line expectation value, instantons or calorons have been shown to be split into fundamental monopoles of fractional instanton charge. In the symmetric phase with trivial Wilson-line expectation value, Bogomol'nyi-Prasad-Sommerfield instanton partons emerge more concretely as non-Abelian Bogomol'nyi-Prasad-Sommerfield monopoles of minimum charge allowed in Dirac quantization.

Long-range psu(2,2|4) Bethe ansatze for gauge theory and strings

International Nuclear Information System (INIS)

Beisert, Niklas; Staudacher, Matthias

2005-01-01

We generalize various existing higher-loop Bethe ansatze for simple sectors of the integrable long-range dynamic spin chain describing planar N=4 super-Yang-Mills theory to the full psu(2,2|4) symmetry and, asymptotically, to arbitrary loop order. We perform a large number of tests of our conjectured equations, such as internal consistency, comparison to direct three-loop diagonalization and expected thermodynamic behavior. In the special case of the su(1|2) subsector, corresponding to a long-range t-J model, we are able to derive, up to three loops, the S-matrix and the associated nested Bethe ansatz from the gauge theory dilatation operator. We conjecture novel all-order S-matrices for the su(1|2) and su(1,1|2) subsectors, and show that they satisfy the Yang-Baxter equation. Throughout the paper, we muse about the idea that quantum string theory on AdS 5 xS 5 is also described by a psu(2,2|4) spin chain. We propose asymptotic all-order Bethe equations for this putative ''string chain'', which differ in a systematic fashion from the gauge theory equations

Remarks on lattice gauge models

International Nuclear Information System (INIS)

Grosse, H.

1981-01-01

The author reports a study of the phase structure of lattice gauge models where one takes as a gauge group a non-abelian discrete subgroup of SU(3). In addition he comments on a lattice action proposed recently by Manton and observes that it violates a positivity property. (Auth.)

Weinberg Angle Derivation from Discrete Subgroups of SU(2 and All That

Directory of Open Access Journals (Sweden)

Potter F.

2015-01-01

Full Text Available The Weinberg angle W of the Standard Model of leptons and quarks is derived from specific discrete (i.e., finite subgroups of the electroweak local gauge group SU(2 L U(1 Y . In addition, the cancellation of the triangle anomaly is achieved even when there are four quark families and three lepton families!

SU(N) lattice gauge theory with Villain's action

International Nuclear Information System (INIS)

Onofri, E.

1981-01-01

The pure gauge lattice theory with Villain's action exp[-A(U)] = GAMMAsub(j=1)sup(N) Σsub(n=-infinity)sup(+infinity) exp[-(N/lambda)(THETAsub(j) + 2nπ) 2 ], where THETA 1 ,..., THETAsub(N) are the invariant angles of U is an element of U(N) or SU(N) is considered. For the two-dimensional lattice the partition function Z(lambda,N) is calculated with the specific heat, the level density rhosub(N)(THETA) and Wilson's loops Wsub(n) = (1/N) (n = 1,2,3,...). The 1/N expansion of Z and Wsub(n) is convergent for sufficiently small |lambda/N| and its coefficients are analytic in lambda near the real axis (no ''Gross-Witten'' singularity to all orders in 1/N), but it is still not possible to commute the strong-coupling limit with the planar limit (lambda→infinity, N→infinity). The character expansion which is needed for strong-coupling calculations in four dimensions is also calculated. A comparison with Monte Carlo data (N=2) and a preliminary discussion of the large-N limit is given. (author)

Remarks on lattice gauge models

International Nuclear Information System (INIS)

Grosse, H.

1981-01-01

The author reports on a study of the phase structure of lattice gauge models where one takes as a gauge group a non-abelian discrete subgroup of SU(3). In addition he comments on a lattice action proposed recently by Manton (1980) and observes that it violates a positivity property. (Auth.)

Wigner's little group as a gauge generator in linearized gravity theories

International Nuclear Information System (INIS)

Scaria, Tomy; Chakraborty, Biswajit

2002-01-01

We show that the translational subgroup of Wigner's little group for massless particles in 3 + 1 dimensions generates gauge transformation in linearized Einstein gravity. Similarly, a suitable representation of the one-dimensional translational group T(1) is shown to generate gauge transformation in the linearized Einstein-Chern-Simons theory in 2 + 1 dimensions. These representations are derived systematically from appropriate representations of translational groups which generate gauge transformations in gauge theories living in spacetime of one higher dimension by the technique of dimensional descent. The unified picture thus obtained is compared with a similar picture available for vector gauge theories in 3 + 1 and 2 + 1 dimensions. Finally, the polarization tensor of the Einstein-Pauli-Fierz theory in 2 + 1 dimensions is shown to split into the polarization tensors of a pair of Einstein-Chern-Simons theories with opposite helicities suggesting a doublet structure for the Einstein-Pauli-Fierz theory

Higgs compositeness in Sp(2N) gauge theories — The pure gauge model

Science.gov (United States)

Bennett, Ed; Ki Hong, Deog; Lee, Jong-Wan; David Lin, C.-J.; Lucini, Biagio; Piai, Maurizio; Vadacchino, Davide

2018-03-01

As a first step in the study of Sp(2N) composite Higgs models, we obtained a set of novel numerical results for the pure gauge Sp(4) lattice theory in 3+1 space-time dimensions. Results for the continuum extrapolations of the string tension and the glueball mass spectrum are presented and their values are compared with the same quantities in neighbouring SU(N) models.

Computation of hybrid static potentials in SU(3 lattice gauge theory

Directory of Open Access Journals (Sweden)

Reisinger Christian

2018-01-01

Full Text Available We compute hybrid static potentials in SU(3 lattice gauge theory. We present a method to automatically generate a large set of suitable creation operators with defined quantum numbers from elementary building blocks. We show preliminary results for several channels and discuss, which structures of the gluonic flux tube seem to be realized by the ground states in these channels.

Building models of gauge-mediated supersymmetry breaking without a messenger sector

International Nuclear Information System (INIS)

Arkani-Hamed, N.; Murayama, H.; March-Russell, J.

1998-01-01

We propose a general scheme for constructing models in which the Standard Model (SM) gauge interactions are the mediators of supersymmetry breaking to the fields in the supersymmetric SM, but where the SM gauge groups couple directly to the sector which breaks supersymmetry dynamically. Despite the direct coupling, the models preserve perturbative unification of the SM gauge coupling constants. Furthermore, the supergravity contributions to the squark and slepton masses can be naturally small, typically being much less than 1% of the gauge-mediated (GM) contributions. Both of these goals can be achieved without need of a fine-tuning or a very small coupling constant. This scheme requires run-away directions at the renormalizable level which are only lifted by non-renormalizable terms in the superpotential. To study the proposed scheme in practice, we develop a modified class of models based on SU(N) x SU(N-1) which allows us to gauge an SU(N-2) global symmetry. However, we point out a new problem which can exist in models where the dynamical supersymmetry breaking sector and the ordinary sector are directly coupled - the two-loop renormalization group has contributions which can induce negative (mass) 2 for the squarks and sleptons. We clarify the origin of the problem and argue that it is likely to be surmountable. We give a recipe for a successful model. (orig.)

On the effect of the lattice asymmetry parameter on the phase structure of SU(N) pure gauge theories

International Nuclear Information System (INIS)

Averchenkova, L.A.; Petrov, K.V.; Petrov, V.K.; Zinovjev, G.M.

1998-01-01

The role of the lattice asymmetry parameter ξ in the phase structure description of the SU(2) and SU(3) gluodynamics at finite temperature has been studied analytically in the SU(N)∼Z(N) approach. The properties of thermodynamic quantities have been investigated near the physical border. The effective action which includes the first non-trivial order from the space-like part allows estimates to be made of the phase structure not only close to the physical border but in the whole area of couplings. We find that thermodynamic quantities depend on ξ and this dependence may be strong enough, up to discontinuity over this parameter for some of them. The Hamiltonian formulation of the SU(2) gauge theory on the asymmetric lattice is presented. (orig.)

Deep-inelastic lepton scattering in an SU(3) x U(1) gauge model

International Nuclear Information System (INIS)

Maharana, K.; Sastry, C.V.

1976-01-01

Linear relations and sum rules for deep-inelastic lepton scattering are derived in the light-cone algebra approach from a set of weak, neutral, and electromagnetic currents based on an SU(3) x U(1) gauge model proposed by Schechter and Ueda

Exact partition functions for the Ω-deformed N=2{sup ∗}SU(2) gauge theory

Energy Technology Data Exchange (ETDEWEB)

Beccaria, Matteo; Macorini, Guido [Dipartimento di Matematica e Fisica “Ennio De Giorgi”, Università del Salento,Via Arnesano, 73100 Lecce (Italy); INFN,Via Arnesano, 73100 Lecce (Italy)

2016-07-12

We study the low energy effective action of the Ω-deformed N=2{sup ∗}SU(2) gauge theory. It depends on the deformation parameters ϵ{sub 1},ϵ{sub 2}, the scalar field expectation value a, and the hypermultiplet mass m. We explore the plane ((m/(ϵ{sub 1})),((ϵ{sub 2})/(ϵ{sub 1}))) looking for special features in the multi-instanton contributions to the prepotential, motivated by what happens in the Nekrasov-Shatashvili limit ϵ{sub 2}→0. We propose a simple condition on the structure of poles of the k-instanton prepotential and show that it is admissible at a finite set of points in the above plane. At these special points, the prepotential has poles at fixed positions independent on the instanton number. Besides and remarkably, both the instanton partition function and the full prepotential, including the perturbative contribution, may be given in closed form as functions of the scalar expectation value a and the modular parameter q appearing in special combinations of Eisenstein series and Dedekind η function. As a byproduct, the modular anomaly equation can be tested at all orders at these points. We discuss these special features from the point of view of the AGT correspondence and provide explicit toroidal 1-blocks in non-trivial closed form. The full list of solutions with 1, 2, 3, and 4 poles is determined and described in details.

Skein relations and Wilson loops in Chern-Simons gauge theory

International Nuclear Information System (INIS)

Horne, J.H.

1990-01-01

We derive the skein relations for the fundamental representations of SO(N), Sp(2n), SU(mvertical stroken), and OSp(mvertical stroke2n). These relations can be used recursively to calculate the expectation values of Wilson lines in three-dimensional Chern-Simons gauge theory with these gauge groups. A combination of braiding and tying of Wilson lines completely describes the skein relations. (orig.)

Gauged N=8 supergravity in five dimensions

International Nuclear Information System (INIS)

Guenaydin, M.; Romans, L.J.; Warner, N.P.

1985-01-01

We construct gauged N=8 supergravity theories in five dimensions. Instead of the twenty-seven vector fields of the ungauged theory, the gauged theories contain fifteen vector fields and twelve second-rank antisymmetric tensor fields satisfying self-dual field equations. The fifteen vector fields can be used to gauge any of the fifteen-dimensional semisimple subgroups of SL(6, R), sepcifically SO(p, 6-p) for p=0, 1, 2, 3. The gauged theories also have a physical global SU(1,1) symmetry which survives from the Esub(6(6)) symmetry of the ungauged theory. This SU(1, 1) for the SO(6) gauging is presumably related to that of the chiral N=2 theory in ten dimensions. In our formalism we maintain a composite local USp(8) symmetry analogous to SU(8) in four dimensions. (orig.)

Classification of compactified su( N c ) gauge theories with fermions in all representations

Science.gov (United States)

Anber, Mohamed M.; Vincent-Genod, Loïc

2017-12-01

We classify su( N c ) gauge theories on R^3× S^1 with massless fermions in higher representations obeying periodic boundary conditions along S^1 . In particular, we single out the class of theories that is asymptotically free and weakly coupled in the infrared, and therefore, is amenable to semi-classical treatment. Our study is conducted by carefully identifying the vacua inside the affine Weyl chamber using Verma bases and Frobenius formula techniques. Theories with fermions in pure representations are generally strongly coupled. The only exceptions are the four-index symmetric representation of su(2) and adjoint representation of su( N c ). However, we find a plethora of admissible theories with fermions in mixed representations. A sub-class of these theories have degenerate perturbative vacua separated by domain walls. In particular, su( N c ) theories with fermions in the mixed representations adjoint⊕fundamental and adjoint⊕two-index symmetric admit degenerate vacua that spontaneously break the parity P , charge conjugation C , and time reversal T symmetries. These are the first examples of strictly weakly coupled gauge theories on R^3× S^1 with spontaneously broken C , P , and T symmetries. We also compute the fermion zero modes in the background of monopole-instantons. The monopoles and their composites (topological molecules) proliferate in the vacuum leading to the confinement of electric charges. Interestingly enough, some theories have also accidental degenerate vacua, which are not related by any symmetry. These vacua admit different numbers of fermionic zero modes, and hence, different kinds of topological molecules. The lack of symmetry, however, indicates that such degeneracy might be lifted by higher order corrections. Finally, we study the general phase structure of adjoint⊕fundamental theories in the small circle and decompactification limits.

Phase diagrams of exceptional and supersymmetric lattice gauge theories

Energy Technology Data Exchange (ETDEWEB)

Wellegehausen, Bjoern-Hendrik

2012-07-10

In this work different strongly-coupled gauge theories with and without fundamental matter have been studied on the lattice with an emphasis on the confinement problem and the QCD phase diagram at nonvanishing net baryon density as well as on possible supersymmetric extensions of the standard model of particle physics. In gauge theories with a non-trivial centre symmetry, as for instance SU(3)-Yang-Mills theory, confinement is intimately related to the centre of the gauge group, and the Polyakov loop serves as an order parameter for confinement. In QCD, this centre symmetry is explicitly broken by quarks in the fundamental representation of the gauge group. But still quarks and gluons are confined in mesons, baryons and glueballs at low temperatures and small densities, suggesting that centre symmetry is not responsible for the phenomenon of confinement. Therefore it is interesting to study pure gauge theories without centre symmetry. In this work this has been done by replacing the gauge group SU(3) of the strong interaction with the exceptional Lie group G{sub 2}, that has a trivial centre. To investigate G{sub 2} gauge theory on the lattice, a new and highly efficient update algorithm has been developed, based on a local HMC algorithm. Employing this algorithm, the proposed and already investigated first order phase transition from a confined to a deconfined phase has been confirmed, showing that indeed a first order phase transition without symmetry breaking or an order parameter is possible. In this context, also the deconfinement phase transition of the exceptional Lie groups F4 and E6 in three spacetime dimensions has been studied. It has been shown that both theories also possess a first order phase transition.

Phase diagrams of exceptional and supersymmetric lattice gauge theories

International Nuclear Information System (INIS)

Wellegehausen, Bjoern-Hendrik

2012-01-01

In this work different strongly-coupled gauge theories with and without fundamental matter have been studied on the lattice with an emphasis on the confinement problem and the QCD phase diagram at nonvanishing net baryon density as well as on possible supersymmetric extensions of the standard model of particle physics. In gauge theories with a non-trivial centre symmetry, as for instance SU(3)-Yang-Mills theory, confinement is intimately related to the centre of the gauge group, and the Polyakov loop serves as an order parameter for confinement. In QCD, this centre symmetry is explicitly broken by quarks in the fundamental representation of the gauge group. But still quarks and gluons are confined in mesons, baryons and glueballs at low temperatures and small densities, suggesting that centre symmetry is not responsible for the phenomenon of confinement. Therefore it is interesting to study pure gauge theories without centre symmetry. In this work this has been done by replacing the gauge group SU(3) of the strong interaction with the exceptional Lie group G 2 , that has a trivial centre. To investigate G 2 gauge theory on the lattice, a new and highly efficient update algorithm has been developed, based on a local HMC algorithm. Employing this algorithm, the proposed and already investigated first order phase transition from a confined to a deconfined phase has been confirmed, showing that indeed a first order phase transition without symmetry breaking or an order parameter is possible. In this context, also the deconfinement phase transition of the exceptional Lie groups F4 and E6 in three spacetime dimensions has been studied. It has been shown that both theories also possess a first order phase transition.

Conformal Windows of SU(N) Gauge Theories, Higher Dimensional Representations and The Size of The Unparticle World

CERN Document Server

Ryttov, Thomas A

2007-01-01

We present the conformal windows of SU(N) supersymmetric and nonsupersymmetric gauge theories with vector-like matter transforming according to higher irreducible representations of the gauge group. We determine the fraction of asymptotically free theories expected to develop an infrared fixed point and find that it does not depend on the specific choice of the representation. This result is exact in supersymmetric theories while it is an approximate one in the nonsupersymmetric case. The analysis allows us to size the unparticle world related to the existence of underlying gauge theories developing an infrared stable fixed point. We find that exactly 50 % of the asymptotically free theories can develop an infrared fixed point while for the nonsupersymmetric theories it is circa 25 %. When considering multiple representations, only for the nonsupersymmetric case, the conformal regions quickly dominate over the nonconformal ones. For four representations, 70 % of the asymptotically free space is filled by the ...

Gravitation as Gauge theory of Poincare Group

International Nuclear Information System (INIS)

Stedile, E.

1982-08-01

The geometrical approach to gauge theories, based on fiber-bundles, is shown in detail. Several gauge formalisms for gravitation are examined. In particular, it is shown how to build gauge theories for non-semisimple groups. A gravitational theory for the Poincare group, with all the essential characteristics of a Yang-Mills theory is proposed. Inonu-Wigner contractions of gauge theories are introduced, which provide a Lagrangian formalism, equivalent to a Lagrangian de Sitter theory supplemented by weak constraints. Yang and Einstein theories for gravitation become particular cases of a Yang-Mills theory. The classical limit of the proposed formalism leads to the Poisson equation, for the static case. (Author) [pt

On the zero mode of the Poisson gauge theory

International Nuclear Information System (INIS)

Saidi, E.H.

1990-09-01

The fundamentals of the Diff(S 2 ) and the SDiff(S 2 ) gauge theories are developed. It is shown that the adjoint representation of SU(∞) is described by a divergentless two dimensional vector field defined on the sphere. The SU(∞) Yang-Mills gauge action obtained earlier by Floratos et al. is reviewed. The problem of the zero modes is solved without need of any constraint. The fundamental representations of SU(∞) and the gauge matter couplings are discussed. (author). 6 refs

SU(2) with fundamental fermions and scalars

Science.gov (United States)

Hansen, Martin; Janowski, Tadeusz; Pica, Claudio; Toniato, Arianna

2018-03-01

We present preliminary results on the lattice simulation of an SU(2) gauge theory with two fermion flavors and one strongly interacting scalar field, all in the fundamental representation of SU(2). The motivation for this study comes from the recent proposal of "fundamental" partial compositeness models featuring strongly interacting scalar fields in addition to fermions. Here we describe the lattice setup for our study of this class of models and a first exploration of the lattice phase diagram. In particular we then investigate how the presence of a strongly coupled scalar field affects the properties of light meson resonances previously obtained for the SU(2) model. Preprint: CP3-Origins-2017-047 DNRF90

S-duality in N = 4 supersymmetric gauge theories with arbitrary gauge group

International Nuclear Information System (INIS)

Dorey, Nicholas; Fraser, Christophe; Hollowood, Timothy J.; Kneipp, Marco A.C.

1996-12-01

The Goddard, Nuyts and Olive conjecture for electric-magnetic duality in the Yang-Mills theory with an arbitrary gauge group G is extended by including a non-vanishing vacuum angle θ. This extended S-duality conjecture includes the case when the unbroken gauge group in non-Abelian and a definite prediction for the spectrum of dyons results. (author)

Hadronic bound states in SU(2) from Dyson-Schwinger equations

Energy Technology Data Exchange (ETDEWEB)

Vujinovic, Milan [Karl-Franzens-Universitaet Graz, Institut fuer Physik, Graz (Austria); Williams, Richard [Justus-Liebig-Universitaet Giessen, Institut fuer Theoretische Physik, Giessen (Germany)

2015-03-01

By using the Dyson-Schwinger/Bethe-Salpeter formalism in Euclidean spacetime, we calculate the ground state spectrum of J ≤ 1 hadrons in an SU(2) gauge theory with two fundamental fermions. We show that the rainbow-ladder truncation, commonly employed in QCD studies, is unsuitable for a description of an SU(2) theory. This we remedy by truncating at the level of the quark-gluon vertex Dyson-Schwinger equation in a diagrammatic expansion. Results obtained within this novel approach show good agreement with lattice studies. These findings emphasize the need to use techniques more sophisticated than rainbow-ladder when investigating generic strongly interacting gauge theories. (orig.)

Unified models of interactions with gauge-invariant variables

International Nuclear Information System (INIS)

Zet, Gheorghe

2000-01-01

A model of gauge theory is formulated in terms of gauge-invariant variables over a 4-dimensional space-time. Namely, we define a metric tensor g μν ( μ , ν = 0,1,2,3) starting with the components F μν a and F μν a tilde of the tensor associated to the Yang-Mills fields and its dual: g μν = 1/(3Δ 1/3 ) (ε abc F μα a F αβ b tilde F βν c ). Here Δ is a scale factor which can be chosen of a convenient form so that the theory may be self-dual or not. The components g μν are interpreted as new gauge-invariant variables. The model is applied to the case when the gauge group is SU(2). For the space-time we choose two different manifolds: (i) the space-time is R x S 3 , where R is the real line and S 3 is the three-dimensional sphere; (ii) the space-time is endowed with axial symmetry. We calculate the components g μν of the new metric for the two cases in terms of SU(2) gauge potentials. Imposing the supplementary condition that the new metric coincides with the initial metric of the space-time, we obtain the field equations (of the first order in derivatives) for the gauge fields. In addition, we determine the scale factor Δ which is introduced in the definition of g μν to ensure the property of self-duality for our SU(2) gauge theory, namely, 1/(2√g)(ε αβστ g μα g νβ F στ a = F μν a , g = det (g μν ). In the case (i) we show that the space-time R x S 3 is not compatible with a self-dual SU(2) gauge theory, but in the case (ii) the condition of self-duality is satisfied. The model developed in our work can be considered as a possible way to unification of general relativity and Yang-Mills theories. This means that the gauge theory can be formulated in the close analogy with the general relativity, i.e. the Yang-Mills equations are equivalent to Einstein equations with the right-hand side of a simple form. (authors)

One-instanton calculations in N=2 supersymmetric gauge theories

International Nuclear Information System (INIS)

Ito, Katsushi

1998-01-01

We study the low-energy effective action of N=2 supersymmetric gauge theories in the Coulomb branch. Using microscopic instanton calculus, we compute the one-instanton contribution to the pre potential for N=2 supersymmetric SU(N c ) Yang-Mills theory. We show that the microscopic result agrees with the exact solution. (Author). 23 refs

Multigrid methods for the computation of propagators in gauge fields

International Nuclear Information System (INIS)

Kalkreuter, T.

1992-11-01

In the present work generalizations of multigrid methods for propagators in gauge fields are investigated. We discuss proper averaging operations for bosons and for staggered fermions. An efficient algorithm for computing C numerically is presented. The averaging kernels C can be used not only in deterministic multigrid computations, but also in multigrid Monte Carlo simulations, and for the definition of block spins and blocked gauge fields in Monte Carlo renormalization group studies of gauge theories. Actual numerical computations of kernels and propagators are performed in compact four-dimensional SU(2) gauge fields. (orig./HSI)

Nonperturbative β function of eight-flavor SU(3) gauge theory

Science.gov (United States)

Hasenfratz, Anna; Schaich, David; Veernala, Aarti

2015-06-01

We present a new lattice study of the discrete β function for SU(3) gauge theory with N f = 8 massless flavors of fermions in the fundamental representation. Using the gradient flow running coupling, and comparing two different nHYP-smeared staggered lattice actions, we calculate the 8-flavor step-scaling function at significantly stronger couplings than were previously accessible. Our continuum-extrapolated results for the discrete β function show no sign of an IR fixed point up to couplings of g 2 ≈ 14. At the same time, we find that the gradient flow coupling runs much more slowly than predicted by two-loop perturbation theory, reinforcing previous indications that the 8-flavor system possesses nontrivial strongly coupled IR dynamics with relevance to BSM phenomenology.

Geometrical theory of ghost and Higgs fields and SU(2/1)

International Nuclear Information System (INIS)

Ne'eman, Y.; Thierry-Mieg, J.

1979-10-01

That a Principal Fiber Bundle provides a precise geometrical representation of Yang-Mills gauge theories has been known since 1963 and used since 1975. This work presents an entirely new domain of applications. The Feynman-DeWitt-Fadeev-Popov ghost-fields required in the renormalization procedure are identified with geometrical objects in the Principal Bundle. This procedure directly yields the BRS equations guaranteeing unitarity and Slavnov-Taylor invariance of the quantum effective Lagrangian. Except for one ghost field and its variation, this entire symmetry thus corresponds to classical notions, in that it is geometrical, and completely independent of the gauge-fixing procedure, which determines the quantized Lagrangian. These results may be used to fix the signs associated with the various ghost loops of quantum supergravity. The result is based upon the identification of a geometrical Z(2) x Z(2) double-gradation of the generalized fields in supergravity: [physical/ghost] fields and [integer/half integer] spins. Then the case of a supergroup as an internal symmetry gauge is considered. Ghosts geometrically associated to odd generators may be identified with the Goldstone-Nambu Higgs-Kibble scalar fields of conventional models with spontaneous symmetry breakdown. As an example, the chiral SU(3)/sub L/ x SU(3)/sub R/ flavor symmetry is realized by gauging the supergroup Q(3).Lastly, the main results concerning asthenodynamics (Weak-EM Unification) as given by the ghost-gauge SU(2/1) supergroup are recalled. 1 table

Disconnected forms of the standard group

International Nuclear Information System (INIS)

McInnes, B.

1996-10-01

Recent work in quantum gravity has led to a revival of interest in the concept of disconnected gauge groups. Here we explain how to classify all of the (non-trivial) groups which have the same Lie algebra as the ''standard group'', SU(3) x SU(2) x U(1), without requiring connectedness. The number of possibilities is surprisingly large. We also discuss the geometry of the ''Kiskis effect'', the ambiguity induced by non-trivial spacetime topology in such gauge theories. (author). 12 refs

Mirror symmetry in three-dimensional gauge theories, quivers and D-branes

International Nuclear Information System (INIS)

De Boer, J.; Ernest Orlando Lawrence Berkeley Nat. Lab., CA; Hori, K.; Ernest Orlando Lawrence Berkeley Nat. Lab., CA; Ooguri, H.; Ernest Orlando Lawrence Berkeley Nat. Lab., CA; Oz, Y.; Ernest Orlando Lawrence Berkeley Nat. Lab., CA

1997-01-01

We construct and analyze dual N=4 supersymmetric gauge theories in three dimensions with unitary and symplectic gauge groups. The gauge groups and the field content of the theories are encoded in quiver diagrams. The duality exchanges the Coulomb and Higgs branches and the Fayet-Iliopoulos and mass parameters. We analyze the classical and the quantum moduli spaces of the theories and construct an explicit mirror map between the mass parameters and the Fayet-Iliopoulos parameters of the dual. The results generalize the relation between ALE spaces and moduli spaces of SU(n) and SO(2n) instantons. We interpret some of these results from the string theory viewpoint, for SU(n) by analyzing T-duality and extremal transitions in type II string compactifications, for SO(2n) by using D-branes as probes. Finally, we make a proposal for the moduli space of vacua of these theories in the absence of matter. (orig.)

Fermion Masses and Mixing in SUSY Grand Unified Gauge Models with Extended Gut Gauge Groups

Energy Technology Data Exchange (ETDEWEB)

Chou, Chih-Lung

2005-04-05

The authors discuss a class of supersymmetric (SUSY) grand unified gauge (GUT) models based on the GUT symmetry G x G or G x G x G, where G denotes the GUT group that has the Standard Model symmetry (SU(3){sub c} x SU(2){sub L} x U(1){sub Y}) embedded as a subgroup. As motivated from string theory, these models are constructed without introducing any Higgs field of rani two or higher. Thus all the Higgs fields are in the fundamental representations of the extended GUT symmetry or, when G = SO(10), in the spinorial representation. These Higgs fields, when acquiring their vacuum expectation values, would break the extended GUT symmetry down to the Standard Model symmetry. In this dissertation, they argue that the features required of unified models, such as the Higgs doublet-triplet splitting, proton stability, and the hierarchy of fermion masses and mixing angles, could have natural explanations in the framework of the extended SUSY GUTs. Furthermore, they argue that the frameworks used previously to construct SO(10) GUT models using adjoint Higgs fields can naturally arise from the SO(10) x SO(10) and SO(10) x SO(10) x SO(10) models by integrating out heavy fermions. This observation thus suggests that the traditional SUSY GUT SO(10) theories can be viewed as the low energy effective theories generated by breaking the extended GUT symmetry down to the SO(10) symmetry.

Lattice gauge theory in the microcanonical ensemble

International Nuclear Information System (INIS)

Callaway, D.J.E.; Rahman, A.

1983-01-01

The microcanonical-ensemble formulation of lattice gauge theory proposed recently is examined in detail. Expectation values in this new ensemble are determined by solving a large set of coupled ordinary differential equations, after the fashion of a molecular dynamics simulation. Following a brief review of the microcanonical ensemble, calculations are performed for the gauge groups U(1), SU(2), and SU(3). The results are compared and contrasted with standard methods of computation. Several advantages of the new formalism are noted. For example, no random numbers are required to update the system. Also, this update is performed in a simultaneous fashion. Thus the microcanonical method presumably adapts well to parallel processing techniques, especially when the p action is highly nonlocal (such as when fermions are included)

Infrared conformality and bulk critical points: SU(2) with heavy adjoint quarks

CERN Document Server

Lucini, Biagio; Rago, Antonio; Rinaldi, Enrico

2013-01-01

The lattice phase structure of a gauge theory can be a serious obstruction to Monte Carlo studies of its continuum behaviour. This issue is particularly delicate when numerical studies are performed to determine whether a theory is in a (near-)conformal phase. In this work we investigate the heavy mass limit of the SU(2) gauge theory with Nf=2 adjoint fermions and its lattice phase diagram, showing the presence of a critical point ending a line of first order bulk phase transition. The relevant gauge observables and the low-lying spectrum are monitored in the vicinity of the critical point with very good control over different systematic effects. The scaling properties of masses and susceptibilities open the possibility that the effective theory at criticality is a scalar theory in the universality class of the four-dimensional Gaussian model. This behaviour is clearly different from what is observed for SU(2) gauge theory with two dynamical adjoint fermions, whose (near-)conformal numerical signature is henc...

Non-planar diagrams in the large N limit of U(N) and SU(N) lattice gauge theories

International Nuclear Information System (INIS)

Weingarten, D.

1980-01-01

It is shown that the limit as N → infinitely with g 2 N fixed of the strong coupling expansion for the vacuum expectation values of a U(N) or SU(N) lattice gauge theory is not given by a sum of planar diagrams. This contradicts a result claimed by De Wit and 't Hooft. (orig.)

Model independent approach to studies of the confining dual Abrikosov vortex in SU(2) lattice gauge theory

International Nuclear Information System (INIS)

Haymaker, Richard W.; Matsuki, Takayuki

2007-01-01

We address the problem of determining the type I, type II or borderline dual superconductor behavior in maximal Abelian gauge SU(2) through the study of the dual Abrikosov vortex. We find that significant electric currents in the simulation data call into question the use of the dual Ginzburg-Landau Higgs model in interpreting the data. Further, two definitions of the penetration depth parameter take two different values. The splitting of this parameter into two is intricately connected to the existence of electric currents. It is important in our approach that we employ definitions of flux and electric and magnetic currents that respect Maxwell equations exactly for lattice averages independent of lattice spacings. Applied to specific Wilson loop sizes, our conclusions differ from those that use the dual GLH model

Gauge invariance and radiative corrections in an extra dimensional theory

International Nuclear Information System (INIS)

Novales-Sanchez, H; Toscano, J J

2011-01-01

The gauge structure of the four dimensional effective theory originated in a pure five dimensional Yang-Mills theory compactified on the orbifold S 1 /Z 2 , is discussed on the basis of the BRST symmetry. If gauge parameters propagate in the bulk, the excited Kaluza-Klein (KK) modes are gauge fields and the four dimensional theory is gauge invariant only if the compactification is carried out by using curvatures as fundamental objects. The four dimensional theory is governed by two types of gauge transformations, one determined by the KK zero modes of the gauge parameters and the other by the excited ones. Within this context, a gauge-fixing procedure to quantize the KK modes that is covariant under the first type of gauge transformations is shown and the ghost sector induced by the gauge-fixing functions is presented. If the gauge parameters are confined to the usual four dimensional space-time, the known result in the literature is reproduced with some minor variants, although it is emphasized that the excited KK modes are not gauge fields, but matter fields transforming under the adjoint representation of SU 4 (N). A calculation of the one-loop contributions of the excited KK modes of the SU L (2) gauge group on the off-shell W + W - V, with V a photon or a Z boson, is exhibited. Such contributions are free of ultraviolet divergences and well-behaved at high energies.

Gauge theory of gravity and supergravity on a group manifold

International Nuclear Information System (INIS)

Ne'eman, Y.; Regge, T.

1977-12-01

The natural arena for the physics of gravity, supergravity and their enlargements appears to be the group manifold of the Poincare group P, the graded Poincare group GP of supersymmetry, and the corresponding enlargements. The dynamics of these theories correspond to geometrical algorithms in P and GP. Differential geometry on Lie groups is reviewed and results applied to P and GP. Curvature, gauge transformations and factorization are introduced. Also reviewed is the general coordinate transformation group and a hybrid gauge transformation, the anholonomized G.C.T. gauge. A study is made of the construction of an action, including the introduction of a set of special 2 forms, the ''pseudo curvatures.'' The possibilities of factorization in supersymmetry are analyzed. The version of supergravity is present which has now become a completely geometrical theory

The end point of the first-order phase transition of the SU(2) gauge-Higgs model on a four-dimensional isotropic lattice

International Nuclear Information System (INIS)

Aoki, Y.; Csikor, F.; Fodor, Z.; Ukawa, A.

1999-01-01

We report results of a study of the end point of the electroweak phase transition of the SU(2) gauge-Higgs model defined on a four-dimensional isotropic lattice with N t = 2. Finite-size scaling study of Lee-Yang zeros yields λ c = 0.00116(16) for the end point. Combined with a zero-temperature measurement of Higgs and W boson masses, this leads to M H,c = 68.2 ± 6.6 GeV for the critical Higgs boson mass. An independent analysis of Binder cumulant gives a consistent value λ c = 0.00102(3) for the end point

Spinor matter fields in SL(2,C) gauge theories of gravity: Lagrangian and Hamiltonian approaches

Science.gov (United States)

Antonowicz, Marek; Szczyrba, Wiktor

1985-06-01

We consider the SL(2,C)-covariant Lagrangian formulation of gravitational theories with the presence of spinor matter fields. The invariance properties of such theories give rise to the conservation laws (the contracted Bianchi identities) having in the presence of matter fields a more complicated form than those known in the literature previously. A general SL(2,C) gauge theory of gravity is cast into an SL(2,C)-covariant Hamiltonian formulation. Breaking the SL(2,C) symmetry of the system to the SU(2) symmetry, by introducing a spacelike slicing of spacetime, we get an SU(2)-covariant Hamiltonian picture. The qualitative analysis of SL(2,C) gauge theories of gravity in the SU(2)-covariant formulation enables us to define the dynamical symplectic variables and the gauge variables of the theory under consideration as well as to divide the set of field equations into the dynamical equations and the constraints. In the SU(2)-covariant Hamiltonian formulation the primary constraints, which are generic for first-order matter Lagrangians (Dirac, Weyl, Fierz-Pauli), can be reduced. The effective matter symplectic variables are given by SU(2)-spinor-valued half-forms on three-dimensional slices of spacetime. The coupled Einstein-Cartan-Dirac (Weyl, Fierz-Pauli) system is analyzed from the (3+1) point of view. This analysis is complete; the field equations of the Einstein-Cartan-Dirac theory split into 18 gravitational dynamical equations, 8 dynamical Dirac equations, and 7 first-class constraints. The system has 4+8=12 independent degrees of freedom in the phase space.

Spinor matter fields in SL(2,C) gauge theories of gravity: Lagrangian and Hamiltonian approaches

International Nuclear Information System (INIS)

Antonowicz, M.; Szczyrba, W.

1985-01-01

We consider the SL(2,C)-covariant Lagrangian formulation of gravitational theories with the presence of spinor matter fields. The invariance properties of such theories give rise to the conservation laws (the contracted Bianchi identities) having in the presence of matter fields a more complicated form than those known in the literature previously. A general SL(2,C) gauge theory of gravity is cast into an SL(2,C)-covariant Hamiltonian formulation. Breaking the SL(2,C) symmetry of the system to the SU(2) symmetry, by introducing a spacelike slicing of spacetime, we get an SU(2)-covariant Hamiltonian picture. The qualitative analysis of SL(2,C) gauge theories of gravity in the SU(2)-covariant formulation enables us to define the dynamical symplectic variables and the gauge variables of the theory under consideration as well as to divide the set of field equations into the dynamical equations and the constraints. In the SU(2)-covariant Hamiltonian formulation the primary constraints, which are generic for first-order matter Lagrangians (Dirac, Weyl, Fierz-Pauli), can be reduced. The effective matter symplectic variables are given by SU(2)-spinor-valued half-forms on three-dimensional slices of spacetime. The coupled Einstein-Cartan-Dirac (Weyl, Fierz-Pauli) system is analyzed from the (3+1) point of view. This analysis is complete; the field equations of the Einstein-Cartan-Dirac theory split into 18 gravitational dynamical equations, 8 dynamical Dirac equations, and 7 first-class constraints. The system has 4+8 = 12 independent degrees of freedom in the phase space

A generalized Wigner function for quantum systems with the SU(2) dynamical symmetry group

International Nuclear Information System (INIS)

Klimov, A B; Romero, J L

2008-01-01

We introduce a Wigner-like quasidistribution function to describe quantum systems with the SU(2) dynamic symmetry group. This function is defined in a three-dimensional group manifold and can be used to represent the states defined in several SU(2) invariant subspaces. The explicit differential Moyal-like form of the star product is found and analyzed in the semiclassical limit

Static, self-dual, finite action SU(3) gauge fields in the de Sitter space

International Nuclear Information System (INIS)

Chakrabarti, A.; Comtet, A.; Viswanathan, K.S.; Simon Fraser Univ., Burnaby, British Columbia

1980-01-01

Static, self-dual, finite action SU(3) gauge fields are constructed on the euclidean section of the positive curvature de Sitter metric with periodic time. Their relation to known time dependent flat space solutions is pointed out. Their significances and possible applications are indicated. (orig.)

On the value and origin of the chiral condensate in quenched SU(2) lattice gauge theory

International Nuclear Information System (INIS)

Hands, S.J.; Teper, M.; Oxford Univ.

1990-01-01

We present results of a numerical calculation of the chiral condensate in quenched SU(2) lattice gauge theory. The calculation proceeds by evaluating the spectral density distribution function for small eigenvalues on both the original lattice and after a factor-of-two blocking. It is performed on lattices as large as 20 4 and for couplings as small as β=4/g 2 =2.6. The fitted values of the condensate as a function of β show good evidence for scaling and universality when compared with string tension measurements at the same value. At the smallest lattice spacings considered, we find evidence that a separation of length scales between ultraviolet fluctuations and those responsible for chiral symmetry breaking has occurred. A more qualitative study yields a significant correlation between the small modes vertical stroken> responsible for the non-zero value of and topological activity as revealed by the expectation value 5 x1/n(>, and hence provides evidence for a topological origin of chiral symmetry breaking. Our interpretation is supported by a subsidiary calculation of the topological susceptibility of the vacuum. (orig.)

On the SL(2,R) symmetry in Yang-Mills theories in the Landau, Curci-Ferrari and maximal abelian gauge

International Nuclear Information System (INIS)

Dudal, David; Verschelde, Henri; Rodino Lemes, Vitor Emanuel; Sarandy, Marcelo S.; Sorella, Silvio Paolo; Picariello, Marco

2002-01-01

The existence of a SL(2;R) symmetry is discussed in SU(N) Yang-Mills in the maximal abelian gauge. This symmetry, also present in the Landau and Curci-Ferrari gauge, ensures the absence of tachyons in the maximal abelian gauge. In all these gauges, SL(2;R) turns out to be dynamically broken by ghost condensates. (author)

Abelian projection on the torus for general gauge groups

International Nuclear Information System (INIS)

Ford, C.; Tok, T.; Wipf, A.

1999-01-01

We consider Yang-Mills theories with general gauge groups G and twists of the four-torus. We find consistent boundary conditions for gauge fields in all instanton sectors. An extended abelian projection with respect to the Polyakov loop operator is presented, where A 0 is independent of time and in the Cartan subalgebra. Fundamental domains for the gauge fixed A 0 are constructed for arbitrary gauge groups. In the sectors with non-vanishing instanton number such gauge fixings are necessarily singular. The singularities can be restricted to Dirac strings joining magnetically charged defects. The magnetic charges of these monopoles take their values in the co-root lattice of the gauge group. We relate the magnetic charges of the defects and the windings of suitable Higgs fields about these defects to the instanton number

Monopole charges in unified gauge theories

CERN Document Server

Chan Hong Mo

1981-01-01

Monopole charges, being global quantities, depend on the gauge group of a theory, which in turn is determined by the representations of all its fields. For example, chromodynamics in its present form when combined with electrodynamics has as its gauge group not SU(3)*U(1) but a 'smaller' group U(3). The specification of monopole charges for a theory can thus be quite intricate. The authors report the result of an investigation in several current gauge theories. Of particular interest is the possible existence in some theories of monopoles carrying multiplicative charges. As a by-product, some earlier assertions seem to be incorrect, are clarified. (16 refs).

On the structure of generalized monopole solutions in gauge-theories

International Nuclear Information System (INIS)

Horvath, Z.; Palla, L.

1976-01-01

A method is presented for constructing generalized 't Hooft monopole solutions in a gauge theory with an arbitrary gauge group. Restrictions arising from the condition of finite energy are derived. The radial oscillation of the solution is discussed. Using this method all the SU(3) solutions known in the literature are reproduced. Finite energy monopoles possessing magnetic charge in the range g 0 0 0 are found in SU(N) gauge theories. Different charge quantization conditions are analyzed to understand the structure of the solutions. (Auth.)

Semiclassical analysis of the weak-coupling limit of SU(2) lattice gauge theory: The subspace of constant fields

International Nuclear Information System (INIS)

Bartels, J.; Wu, T.T.

1988-01-01

This paper contains the first part of a systematic semiclassical analysis of the weak-coupling limit of lattice gauge theories, using the Hamiltonian formulation. The model consists of an N 3 cubic lattice of pure SU(2) Yang-Mills theory, and in this first part we limit ourselves to the subspace of constant field configurations. We investigate the flow of classical trajectories, with a particular emphasis on the existence and location of caustics. There the ground-state wave function is expected to peak. It is found that regions densely filled with caustics are very close to the origin, i.e., in the domain of weak field configurations. This strongly supports the expectation that caustics are essential for quantities of physical interest

Adventures in Coulomb Gauge

International Nuclear Information System (INIS)

Greensite, J.; Olejnik, S.

2003-01-01

We study the phase structure of SU(2) gauge theories at zero and high temperature, with and without scalar matter fields, in terms of the symmetric/broken realization of the remnant gauge symmetry which exists after fixing to Coulomb gauge. The symmetric realization is associated with a linearly rising color Coulomb potential (which we compute numerically), and is a necessary but not sufficient condition for confinement.

Preliminary analysis of the phases of 4d SU(2) Higgs gauge systems with cutoff at the Gribov horizon

International Nuclear Information System (INIS)

Capri, Marcio A.L.; Gomez, Arthuro J.; Guimaraes, Marcelo S.; Justo, Igor F.; Sorella, Silvio P.; Vercauteren, David; Dudal, David

2013-01-01

Full text: We study the gauge propagators of a SU(2) 4d Yang-Mills theory in the presence of the Higgs field by taking into account non-perturbative effects related to the Gribov copies, which affect the gauge fixing procedure. Both fundamental and adjoint representation for the Higgs field are considered. An interesting feature of our results is the deep difference between the fundamental and adjoint representations. In synthesis, in the fundamental representation three regions are observed: the first, called the Higgs region, is the region in which the propagators are not affected by the Gribov problem, being of the Yukawa type; the second region is an intermediate region where the gauge propagator can be decomposed into the sum of two Yukawa terms, one of them being unphysical, due to the negativity of its residue; the third region is a region in which the propagators are of the Gribov type, exhibiting complex poles. As such, they correspond to the confined region. We underline that the propagators change smoothly when one goes from one region to another, a feature which is in agreement with lattice results. The adjoint representation has a more intricate scenario. For a finite vacuum expectation value of the Higgs field, ν, we always find a U(1) confined mode, meaning that the third component of the gauge field exhibits a Gribov type propagator, while the propagator of the o®-diagonal components varies smoothly from a confined to a Yukawa type propagator. The massless photon is recovered in the limiting case ν→ ∞, as suggested by lattice works. (author)

Irreducible gauge theory of a consolidated Salam-Weinberg model

International Nuclear Information System (INIS)

Ne'eman, Y.

1979-01-01

The Salam-Weinberg model is derived by gauging an internal simple supergroup SU(2/1). The theory uniquely assigns the correct SU(2)sub(L) X U(1) eigenvalues for all leptons, fixes thetasub(W) = 30 0 , generates the W +- sub(sigma), Z 0 sub(sigma) and Asub(sigma) together with the Higgs-Goldstone Isub(L) = 1/2 scalar multiplets as gauge fields, and imposes the standard spontaneous breakdown of SU(2)sub(L) X U(1). The masses of intermediate bosons and fermions are directly generated by SU(2/1) universality, which also fixes the Higgs field coupling. (Auth.)

Monte Carlo simulation of Su(2) lattice gauge theory with internal quark loops

International Nuclear Information System (INIS)

Azcoiti, V.; Nakamura, A.

1982-01-01

Dynamical effects of quark loops in lattice gauge theory with icosahedral group are studied. The standard Wilson action is employed and the fermionic part by a discretize pseudo fermionic method is calculated. The masses of π, rho, ω are computed and the average value of an effective fermionic action is evaluated

On the relation between fields and potentials in non abelian Gauge Theories

International Nuclear Information System (INIS)

Bollini, C.G.; Giambiagi, J.J.

1979-01-01

Some examples have been given in the literature of ambiguous gauge fields, i.e. those not having a unique potential (up to a gauge transformation). An example given by Deser and Wilczek is examined and found the condition (for any gauge group) that the group element generating the potentials must satisfy in order for the potentials not to be related by any gauge transformation. In three dimensions (for Su 2 ) there are other families of ambiguous fields characterized by arbitrary unit vector fields n vector (n vector) (n 2 vector =1). The example given by Wu and Yang belongs to a particular family with n vector = n vector. r vector / r vector. The sources of these fields and some interesting relations between them are also found [pt

Gauge field condensation in geometric quantum chromodynamics

International Nuclear Information System (INIS)

Guendelman, E.I.

1991-09-01

In odd number of dimensions, it is possible to construct general covariant gauge theories, where the metric is not an independent variable, but local function of the gauge fields. Starting from standardly defined gauge theory, upon functional integration of some variables, we could end up with such moodels. For models with SU(2) and SU(3) symmetry in three dimensions, gauge field condensation take place in the vacuum, which is nevertheless homogeneous and isotropic up to a gauge transformation, provided the space is flat. Introducing Higgs fields that spontaneously break the gauge symmetry, we get a breakdown of the homogenity and isotropy of the vacuum. Finally, we discuss how some of this ideas can be generalized to four and other even dimensions. (author)

Path integral quantization of the Symplectic Leaves of the SU(2)*Poisson-Lie Group

International Nuclear Information System (INIS)

Morariu, B.

1997-01-01

The Feynman path integral is used to quantize the symplectic leaves of the Poisson-Lie group SU(2)*. In this way we obtain the unitary representations of Uq(su(2)). This is achieved by finding explicit Darboux coordinates and then using a phase space path integral. I discuss the *-structure of SU(2)* and give a detailed description of its leaves using various parameterizations and also compare the results with the path integral quantization of spin

On the N=1{sup ∗} gauge theory on a circle and elliptic integrable systems

Energy Technology Data Exchange (ETDEWEB)

Bourget, Antoine; Troost, Jan [Laboratoire de Physique Théorique, Ecole Normale Supérieure,24 rue Lhomond, 75005 Paris (France)

2016-01-18

We continue our study of the N=1{sup ∗} supersymmetric gauge theory on ℝ{sup 2,1}×S{sup 1} and its relation to elliptic integrable systems. Upon compactification on a circle, we show that the semi-classical analysis of the massless and massive vacua depends on the classification of nilpotent orbits, as well as on the conjugacy classes of the component group of their centralizer. We demonstrate that semi-classically massless vacua can be lifted by Wilson lines in unbroken discrete gauge groups. The pseudo-Levi subalgebras that play a classifying role in the nilpotent orbit theory are also key in defining generalized Inozemtsev limits of (twisted) elliptic integrable systems. We illustrate our analysis in the N=1{sup ∗} theories with gauge algebras su(3), su(4), so(5) and for the exceptional gauge algebra G{sub 2}. We map out modular duality diagrams of the massive and massless vacua. Moreover, we provide an analytic description of the branches of massless vacua in the case of the su(3) and the so(5) theory. The description of these branches in terms of the complexified Wilson lines on the circle invokes the Eichler-Zagier technique for inverting the elliptic Weierstrass function. After fine-tuning the coupling to elliptic points of order three, we identify the Argyres-Douglas singularities of the su(3)N=1{sup ∗} theory.

Exact renormalization group for gauge theories

International Nuclear Information System (INIS)

Balaban, T.; Imbrie, J.; Jaffe, A.

1984-01-01

Renormalization group ideas have been extremely important to progress in our understanding of gauge field theory. Particularly the idea of asymptotic freedom leads us to hope that nonabelian gauge theories exist in four dimensions and yet are capable of producing the physics we observe-quarks confined in meson and baryon states. For a thorough understanding of the ultraviolet behavior of gauge theories, we need to go beyond the approximation of the theory at some momentum scale by theories with one or a small number of coupling constants. In other words, we need a method of performing exact renormalization group transformations, keeping control of higher order effects, nonlocal effects, and large field effects that are usually ignored. Rigorous renormalization group methods have been described or proposed in the lectures of Gawedzki, Kupiainen, Mack, and Mitter. Earlier work of Glimm and Jaffe and Gallavotti et al. on the /phi/ model in three dimensions were quite important to later developments in this area. We present here a block spin procedure which works for gauge theories, at least in the superrenormalizable case. It should be enlightening for the reader to compare the various methods described in these proceedings-especially from the point of view of how each method is suited to the physics of the problem it is used to study

Lattices in group manifolds

International Nuclear Information System (INIS)

Lisboa, P.; Michael, C.

1982-01-01

We address the question of designing optimum discrete sets of points to represent numerically a continuous group manifold. We consider subsets which are extensions of the regular discrete subgroups. Applications to Monte Carlo simulation of SU(2) and SU(3) gauge theory are discussed. (orig.)

All unitary ray representations of the conformal group SU(2,2) with positive energy

International Nuclear Information System (INIS)

Mack, G.

1975-12-01

We find all those unitary irreducible representations of the infinitely - sheeted covering group G tilde of the conformal group SU(2,2)/Z 4 which have positive energy P 0 >= O. They are all finite component field representations and are labelled by dimension d and a finite dimensional irreducible representation (j 1 , j 2 ) of the Lorentz group SL(2C). They all decompose into a finite number of unitary irreducible representations of the Poincare subgroup with dilations. (orig.) [de

Supersymmetry breaking through confining and dual theory gauge dynamics

International Nuclear Information System (INIS)

Csaki, C.; Massachusetts Inst. of Tech., Cambridge, MA; Randall, L.; Massachusetts Inst. of Tech., Cambridge, MA; Skiba, W.; Massachusetts Inst. of Tech., Cambridge, MA; Leigh, R.G.

1997-01-01

We show that theories in the confining, free magnetic, and conformal phases can break supersymmetry through dynamical effects. To illustrate this, we present theories based on the gauge groups SU(n) x SU(4) x U(1) and SU(n) x SU(5) x U(1) with the field content obtained by decomposing an SU(m) theory with an antisymmetric tensor and m - 4 antifundamentals. (orig.)

Unified Gauge Theories and Reduction of Couplings: from Finiteness to Fuzzy Extra Dimensions

Directory of Open Access Journals (Sweden)

George Zoupanos

2008-02-01

Full Text Available Finite Unified Theories (FUTs are N = 1 supersymmetric Grand Unified Theories, which can be made all-loop finite, both in the dimensionless (gauge and Yukawa couplings and dimensionful (soft supersymmetry breaking terms sectors. This remarkable property, based on the reduction of couplings at the quantum level, provides a drastic reduction in the number of free parameters, which in turn leads to an accurate prediction of the top quark mass in the dimensionless sector, and predictions for the Higgs boson mass and the supersymmetric spectrum in the dimensionful sector. Here we examine the predictions of two such FUTs. Next we consider gauge theories defined in higher dimensions, where the extra dimensions form a fuzzy space (a finite matrix manifold. We reinterpret these gauge theories as four-dimensional theories with Kaluza-Klein modes. We then perform a generalized à la Forgacs-Manton dimensional reduction. We emphasize some striking features emerging such as (i the appearance of non-Abelian gauge theories in four dimensions starting from an Abelian gauge theory in higher dimensions, (ii the fact that the spontaneous symmetry breaking of the theory takes place entirely in the extra dimensions and (iii the renormalizability of the theory both in higher as well as in four dimensions. Then reversing the above approach we present a renormalizable four dimensional SU(N gauge theory with a suitable multiplet of scalar fields, which via spontaneous symmetry breaking dynamically develops extra dimensions in the form of a fuzzy sphere SN2. We explicitly find the tower of massive Kaluza-Klein modes consistent with an interpretation as gauge theory on M4 × S2, the scalars being interpreted as gauge fields on S2. Depending on the parameters of the model the low-energy gauge group can be SU(n, or broken further to SU(n1 × SU(n2 × U(1. Therefore the second picture justifies the first one in a renormalizable framework but in addition has the potential to

Some physical solutions of Yang's equations for SU (2) gauge fields ...

Indian Academy of Sciences (India)

Some previously obtained physical solutions [1–3] of Yang's equations for (2) gauge fields [4], Charap's equations for pion dynamics [5,6] and their combination as proposed by Chakraborty and Chanda [1] have been presented. They represent different physical characteristics, e.g. spreading wave with solitary profile ...

Instanton effects in three-dimensional supersymmetric gauge theories with matter

NARCIS (Netherlands)

Dorey, N.; Tong, D.; Vandoren, S.

1998-01-01

Using standard field theory techniques we compute perturbative and instanton contributions to the Coulomb branch of three-dimensional supersymmetric QCD with N = 2 and N = 4 supersymmetry and gauge group SU(2). For the N = 4 theory with one massless flavor, we confirm the proposal of Seiberg and

Low energy gauge couplings in grand unified theories and high precision physics

International Nuclear Information System (INIS)

Lynn, B.W.

1993-09-01

I generalize the leading log relations between low energy SU(3) QCD , SU(2) rvec I and U(l) Y effective gauge couplings to include all one-loop threshold effects of matter fields in oblique vector self energy quantum corrections for both supersymmetric and non-supersymmetric SU(5) grand unified theories. These always involve an exactly conserved current from the unbroken SU(3) QCD x U(L) QED subgroup; this fact strongly constrains any non-decoupling of heavy states as well as the generic character of threshold effects. Relations between low energy gauge couplings depend on the details of the spectra of both the superheavy and low mass sectors; I display the common origin of the logs appropriate to superheavy matter states, which can be found with well known renormalization group techniques, and the combination of logs and polynomials appropriate for light matter states, which cannot. Relations between any two or all three low energy effective gauge couplings do not depend on the top quark or standard model Higgs' masses. Neither do they depend on neutral color singlet states such as other neutral color singlet Higgs' or higgsinos, neutrinos, zinos or photinos. Further, they do not depend on degenerate SU(5) matter representations, of either spin 0 or spin 1/2 of any mass; matter representations of SU(5) can affect such relations only if there is mass splitting within them. The b quark splitting from the τ and ν τ can affect the relation between gauge couplings for |q 2 | → m b 2 as can hadronic resonances and multi-hadron states for lower |q 2 |. New mass-split representations of light states, such as occur in supersymmetric theories, can also affect such relations

Low energy gauge couplings in grand unified theories and high precision physics

Energy Technology Data Exchange (ETDEWEB)

Lynn, B.W. [Stanford Univ., CA (United States). Dept. of Physics]|[Superconducting Super Collider Lab., Dallas, TX (United States)

1993-09-01

I generalize the leading log relations between low energy SU(3){sub QCD}, SU(2){sub {rvec I}} and U(l){sub Y} effective gauge couplings to include all one-loop threshold effects of matter fields in oblique vector self energy quantum corrections for both supersymmetric and non-supersymmetric SU(5) grand unified theories. These always involve an exactly conserved current from the unbroken SU(3){sub QCD} {times} U(L){sub QED} subgroup; this fact strongly constrains any non-decoupling of heavy states as well as the generic character of threshold effects. Relations between low energy gauge couplings depend on the details of the spectra of both the superheavy and low mass sectors; I display the common origin of the logs appropriate to superheavy matter states, which can be found with well known renormalization group techniques, and the combination of logs and polynomials appropriate for light matter states, which cannot. Relations between any two or all three low energy effective gauge couplings do not depend on the top quark or standard model Higgs` masses. Neither do they depend on neutral color singlet states such as other neutral color singlet Higgs` or higgsinos, neutrinos, zinos or photinos. Further, they do not depend on degenerate SU(5) matter representations, of either spin 0 or spin 1/2 of any mass; matter representations of SU(5) can affect such relations only if there is mass splitting within them. The b quark splitting from the {tau} and {nu}{sub {tau}} can affect the relation between gauge couplings for {vert_bar}q{sub 2}{vert_bar} {yields} m{sub b}{sup 2} as can hadronic resonances and multi-hadron states for lower {vert_bar}q{sub 2}{vert_bar}. New mass-split representations of light states, such as occur in supersymmetric theories, can also affect such relations.

Hot Conformal Gauge Theories

DEFF Research Database (Denmark)

Mojaza, Matin; Pica, Claudio; Sannino, Francesco

2010-01-01

of flavors. Surprisingly this number, if computed to the order g^2, agrees with previous predictions for the lower boundary of the conformal window for nonsupersymmetric gauge theories. The higher order results tend to predict a higher number of critical flavors. These are universal properties, i......We compute the nonzero temperature free energy up to the order g^6 \\ln(1/g) in the coupling constant for vector like SU(N) gauge theories featuring matter transforming according to different representations of the underlying gauge group. The number of matter fields, i.e. flavors, is arranged...... in such a way that the theory develops a perturbative stable infrared fixed point at zero temperature. Due to large distance conformality we trade the coupling constant with its fixed point value and define a reduced free energy which depends only on the number of flavors, colors and matter representation. We...

The cross-over points in lattice gauge theories with continuous gauge groups

International Nuclear Information System (INIS)

Cvitanovic, P.; Greensite, J.; Lautrup, B.

1981-01-01

We obtain a closed expression for the weak-to-strong coupling cross-over point in all Wilson type lattice gauge theories with continuous gauge groups. We use a weak-coupling expansion of the mean-field self-consistency equation. In all cases where our results can be compared with Monte Carlo calculations the agreement is excellent. (orig.)

Internal space decimation for lattice gauge theories

International Nuclear Information System (INIS)

Flyvbjerg, H.

1984-01-01

By a systematic decimation of internal space lattice gauge theories with continuous symmetry groups are mapped into effective lattice gauge theories with finite symmetry groups. The decimation of internal space makes a larger lattice tractable with the same computational resources. In this sense the method is an alternative to Wilson's and Symanzik's programs of improved actions. As an illustrative test of the method U(1) is decimated to Z(N) and the results compared with Monte Carlo data for Z(4)- and Z(5)-invariant lattice gauge theories. The result of decimating SU(3) to its 1080-element crystal-group-like subgroup is given and discussed. (orig.)

Irreducible gauge theory of a consolidated Salam-Weinberg model

International Nuclear Information System (INIS)

Ne'eman, Y.

1978-10-01

The Salam-Weinberg model is derived by gauging an internal simple supergroup SU(2/1). The theory uniquely assigns the correct SU(2)/sub L/ circle x U(1) eigenvalues for all leptons and quarks, fixes theta /sub w/ = 30 0 , generates the W/sub sigma//sup +-/, Z/sub sigma//sup 0/ and A/sub sigma/ together with the Higgs-Goldstone I/sub L/ = 1/2 scalar multiplets as gauge fields, and imposes the standard spontaneous breakdown of SU(2)/sub L/ circle x U(1). The masses of intermediate bosons and fermions are directly generated by SU(2/1) university, which also fixes the Higgs field coupling

CKM and PMNS mixing matrices from discrete subgroups of SU(2)

International Nuclear Information System (INIS)

Potter, Franklin

2015-01-01

Remaining within the realm of the Standard Model(SM) local gauge group, this first principles derivation of both the PMNS and CKM matrices utilizes quaternion generators of the three discrete (i.e., finite) binary rotational subgroups of SU(2) called [3,3,2], [4,3,2], and [5,3,2] for three lepton families in R 3 and four related discrete binary rotational subgroups [3,3,3], [4,3,3], [3,4,3], and [5,3,3] represented by four quark families in R 4 . The traditional 3x3 CKM matrix is extracted as a submatrix of the 4x4 CKM4 matrix. If these two additional quarks b' and t' of a 4th quark family exist, there is the possibility that the SM lagrangian may apply all the way down to the Planck scale. There are then numerous other important consequences. The Weinberg angle is derived using these same quaternion generators, and the triangle anomaly cancellation is satisfied even though there is an obvious mismatch of three lepton families to four quark families. In a discrete space, one can also use these generators to derive a unique connection from the electroweak local gauge group SU(2) L x U(1) Y acting in R 4 to the discrete group Weyl E 8 in R 8 . By considering Lorentz transformations in discrete (3,1)-D spacetime, one obtains another Weyl E 8 discrete symmetry group in R 8 , so that the combined symmetry is Weyl E 8 x Weyl E 8 = 'discrete' SO(9,1) in 10-D spacetime. This unique connection is in direct contrast to the 10 500 possible connections for superstring theory! (paper)

Towards a manifestly gauge invariant and universal calculus for Jang-Mills theory

International Nuclear Information System (INIS)

Arnone, S.; Gatti, A.; Morris, T.R.

2002-01-01

A manifestly gauge invariant exact renormalization group for pure SU (N) Jang-Mills theory is proposed, along with the necessary gauge invariant regularisation which implements the effective cutoff. The latter is naturally incorporated by embedding the theory into a spontaneously broken SU(N/N) super-gauge theory, which guarantees finiteness to all orders in perturbation theory. The effective action, from which one extracts the physics, can be computed whilst manifestly preserving gauge invariance at each and every step. As an example, we give an elegant computation of the one-loop SU(N) Jang-Mills beta function, for the first time at finite N without any gauge fixing or ghosts. It is also completely independent of the details put in by hand, e.g. the choice of covariantisation and the cutoff profile, and, therefore, guides us to a procedure for streamlined calculations (Authors)

Some approximate calculations in SU2 lattice mean field theory

International Nuclear Information System (INIS)

Hari Dass, N.D.; Lauwers, P.G.

1981-12-01

Approximate calculations are performed for small Wilson loops of SU 2 lattice gauge theory in mean field approximation. Reasonable agreement is found with Monte Carlo data. Ways of improving these calculations are discussed. (Auth.)

Parastatistics and gauge symmetries

International Nuclear Information System (INIS)

Govorkov, A.B.

1982-01-01

A possible formulation of gauge symmetries in the Green parafield theory is analysed and the SO(3) gauge symmetry is shown to be on a distinct status. The Greenberg paraquark hypothesis turns out to be not equivalent to the hypothesis of quark colour SU(3)sub(c) symmetry. Specific features of the gauge SO(3) symmetry are discussed, and a possible scheme where it is an exact subgroup of the broken SU(3)sub(c) symmetry is proposed. The direct formulation of the gauge principle for the parafield represented by quaternions is also discussed

Type IIA orientifolds on SU(2)-structure manifolds

Energy Technology Data Exchange (ETDEWEB)

Danckaert, Thomas

2010-11-15

We investigate the possible supersymmetry-preserving orientifold projections of type IIA string theory on a six-dimensional background with SU(2)-structure. We find two categories of projections which preserve half of the low-energy supersymmetry, reducing the effective theory from an N=4 supergravity theory, to an N=2 supergravity. For these two cases, we impose the projection on the low-energy spectrum and reduce the effective N=4 supergravity action accordingly. We can identify the resulting gauged N=2 supergravity theory and bring the action into canonical form. We compute the scalar moduli spaces and characterize the gauged symmetries in terms of the geometry of these moduli spaces. Due to their origin in N=4 supergravity, which is a highly constrained theory, the moduli spaces are of a very simple form. We find that, for suitable background manifolds, isometries in all scalar sectors can become gauged. The obtained gaugings share many features with those of N=2 supergravities obtained previously from other G-structure compactifications. (orig.)

Dielectric lattice gauge theory

International Nuclear Information System (INIS)

Mack, G.

1983-06-01

Dielectric lattice gauge theory models are introduced. They involve variables PHI(b)epsilong that are attached to the links b = (x+esub(μ),x) of the lattice and take their values in the linear space g which consists of real linear combinations of matrices in the gauge group G. The polar decomposition PHI(b)=U(b)osub(μ)(x) specifies an ordinary lattice gauge field U(b) and a kind of dielectric field epsilonsub(ij)proportionalosub(i)osub(j)sup(*)deltasub(ij). A gauge invariant positive semidefinite kinetic term for the PHI-field is found, and it is shown how to incorporate Wilson fermions in a way which preserves Osterwalder Schrader positivity. Theories with G = SU(2) and without matter fields are studied in some detail. It is proved that confinement holds, in the sense that Wilson loop expectation values show an area law decay, if the Euclidean action has certain qualitative features which imply that PHI = 0 (i.e. dielectric field identical 0) is the unique maximum of the action. (orig.)

Dielectric lattice gauge theory

International Nuclear Information System (INIS)

Mack, G.

1984-01-01

Dielectric lattice gauge theory models are introduced. They involve variables PHI(b)element ofG that are attached to the links b = (x+esub(μ), x) of the lattice and take their values in the linear space G which consists of real linear combinations of matrices in the gauge group G. The polar decomposition PHI(b)=U(b)sigmasub(μ)(x) specifies an ordinary lattice gauge field U(b) and a kind of dielectric field epsilonsub(ij)proportional sigmasub(i)sigmasub(j)sup(*)deltasub(ij). A gauge invariant positive semidefinite kinetic term for the PHI-field is found, and it is shown how to incorporate Wilson fermions in a way which preserves Osterwalder-Schrader positivity. Theories with G = SU(2) and without matter fields are studied in some detail. It is proved that confinement holds, in the sense that Wilson-loop expectation values show an area law decay, if the euclidean action has certain qualitative features which imply that PHI=0 (i.e. dielectric field identical 0) is the unique maximum of the action. (orig.)

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

Some remarks on geodesics in gauge groups and harmonic maps

International Nuclear Information System (INIS)

Valli, G.

1987-08-01

The following topics are discussed: Euler's equations for geodesics in the gauge groups and in gauge orbits of connections, conserved quantities and moment map, existence and uniqueness of solutions for the Cauchy problem, stationary solutions and harmonic bundles, harmonic gauges on Riemann surfaces and Lax pairs, low geodesics in gauge groups over Riemann surfaces produce, by Hodge decomposition, paths of holomorphic differentials. 19 refs

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)

Conformal windows of SU(N) gauge theories, higher dimensional representations, and the size of the unparticle world

International Nuclear Information System (INIS)

Ryttov, Thomas A.; Sannino, Francesco

2007-01-01

We present the conformal windows of SU(N) supersymmetric and nonsupersymmetric gauge theories with vectorlike matter transforming according to higher irreducible representations of the gauge group. We determine the fraction of asymptotically free theories expected to develop an infrared fixed point and find that it does not depend on the specific choice of the representation. This result is exact in supersymmetric theories while it is an approximate one in the nonsupersymmetric case. The analysis allows us to size the unparticle world related to the existence of underlying gauge theories developing an infrared stable fixed point. We find that exactly 50% of the asymptotically free theories can develop an infrared fixed point while for the nonsupersymmetric theories it is circa 25%. When considering multiple representations, only for the nonsupersymmetric case, the conformal regions quickly dominate over the nonconformal ones. For four representations, 70% of the asymptotically free space is filled by the conformal region. According to our theoretical landscape survey the unparticle physics world occupies a sizable amount of the particle world, at least in theory space, and before mixing it (at the operator level) with the nonconformal one

Flipped SU(5) times U(1) in superconformal models

Energy Technology Data Exchange (ETDEWEB)

Bailin, D.; Katechou, E.K. (Sussex Univ., Brighton (United Kingdom). School of Mathematical and Physical Sciences); Love, A. (London Univ. (United Kingdom))

1992-01-10

This paper reports that flipped SU(5) {times} U(1) models are constructed in the framework of tensoring of N = 2 superconformal minimal models quotiented by discrete symmetries. Spontaneous breaking of flipped SU(5) {times} U(1) and extra U(1) factors in the gauge group along F-flat directions of the effective potential is studied.

Left-right gauge symmetry breaking by radiative corrections in supergravity

International Nuclear Information System (INIS)

Moxhay, P.; Yamamoto, K.

1984-01-01

A supersymmetric SU(2)sub(L) x SU(2)sub(R) x U(1)sub(B-L) gauge theory coupled to N = 1 supergravity is investigated. The scale of left-right gauge symmetry breaking is determined as Msub(R) proportional Msub(P) esup(-1/α) by radiative corrections through the logarithmic evolution of soft supersymmetry breakings. SU(2)sub(L) x SU(2)sub(R) x U(1)sub(B-L) may be embedded in SO(10) grand unification. Cosmological implications intrinsic to the present model are also discussed, which may give a constraint Msub(R) approx.= 10 9-12 GeV. (orig.)

Family gauge symmetry as an origin of Koide's mass formula and charged lepton spectrum

International Nuclear Information System (INIS)

Sumino, Y.

2009-01-01

Koide's mass formula is an empirical relation among the charged lepton masses which holds with a striking precision. We present a model of charged lepton sector within an effective field theory with U(3) x SU(2) family gauge symmetry, which predicts Koide's formula within the present experimental accuracy. Radiative corrections as well as other corrections to Koide's mass formula have been taken into account. We adopt a known mechanism, through which the charged lepton spectrum is determined by the vacuum expectation value of a 9-component scalar field Φ. On the basis of this mechanism, we implement the following mechanisms into our model: (1) The radiative correction induced by family gauge interaction cancels the QED radiative correction to Koide's mass formula, assuming a scenario in which the U(3) family gauge symmetry and SU(2) L weak gauge symmetry are unified at 10 2 -10 3 TeV scale; (2) A simple potential of Φ invariant under U(3) x SU(2) leads to a realistic charged lepton spectrum, consistent with the experimental values, assuming that Koide's formula is protected; (3) Koide's formula is stabilized by embedding U(3) x SU(2) symmetry in a larger symmetry group. Formally fine tuning of parameters in the model is circumvented (apart from two exceptions) by appropriately connecting the charged lepton spectrum to the boundary (initial) conditions of the model at the cut-off scale. We also discuss some phenomenological implications.

Topological Quantization of Instantons in SU(2) Yang–Mills Theory

International Nuclear Information System (INIS)

Wo-Jun, Zhong; Yi-Shi, Duan

2008-01-01

By decomposing SU(2) gauge potential in four-dimensional Euclidean SU(2) Yang–Mills theory in a new way, we find that the instanton number related to the isospin defects of a doublet order parameter can be topologically quantized by the Hopf index and Brouwer degree. It is also shown that the instanton number is just the sum of the topological charges of the isospin defects in the non-trivial sector of Yang–Mills theory. (general)

Properties of the twisted Polyakov loop coupling and the infrared fixed point in the SU(3) gauge theories

Science.gov (United States)

Itou, Etsuko

2013-08-01

We report the nonperturbative behavior of the twisted Polyakov loop (TPL) coupling constant for the SU(3) gauge theories defined by the ratio of Polyakov loop correlators in finite volume with twisted boundary condition. We reveal the vacuum structures and the phase structure for the lattice gauge theory with the twisted boundary condition. Carrying out the numerical simulations, we determine the nonperturbative running coupling constant in this renormalization scheme for the quenched QCD and N_f=12 SU(3) gauge theories. First, we study the quenched QCD theory using the plaquette gauge action. The TPL coupling constant has a fake fixed point in the confinement phase. We discuss this fake fixed point of the TPL scheme and obtain the nonperturbative running coupling constant in the deconfinement phase, where the magnitude of the Polyakov loop shows the nonzero values. We also investigate the system coupled to fundamental fermions. Since we use the naive staggered fermion with the twisted boundary condition in our simulation, only multiples of 12 are allowed for the number of flavors. According to the perturbative two-loop analysis, the N_f=12 SU(3) gauge theory might have a conformal fixed point in the infrared region. However, recent lattice studies show controversial results for the existence of the fixed point. We point out possible problems in previous work, and present our careful study. Finally, we find the infrared fixed point (IRFP) and discuss the robustness of the nontrivial IRFP of a many-flavor system under the change of the analysis method. Some preliminary results were reported in the proceedings [E. Bilgici et al., PoS(Lattice 2009), 063 (2009); Itou et al., PoS(Lattice 2010), 054 (2010)] and the letter paper [T. Aoyama et al., arXiv:1109.5806 [hep-lat

Central extensions of some Abelian finite gauge groups

International Nuclear Information System (INIS)

Combe, Ph.; Rodriguez, R.; Sirugue, M.; Sirugue-Collin, M.

1981-01-01

The authors describe central extensions of Abelian finite gauge groups on lattices which are permutation invariant. Moreover some remarks are made on the gauge models on lattice associated with these non-commutative central extensions. (Auth.)

Non Abelian T-duality in Gauged Linear Sigma Models

Science.gov (United States)

Bizet, Nana Cabo; Martínez-Merino, Aldo; Zayas, Leopoldo A. Pando; Santos-Silva, Roberto

2018-04-01

Abelian T-duality in Gauged Linear Sigma Models (GLSM) forms the basis of the physical understanding of Mirror Symmetry as presented by Hori and Vafa. We consider an alternative formulation of Abelian T-duality on GLSM's as a gauging of a global U(1) symmetry with the addition of appropriate Lagrange multipliers. For GLSMs with Abelian gauge groups and without superpotential we reproduce the dual models introduced by Hori and Vafa. We extend the construction to formulate non-Abelian T-duality on GLSMs with global non-Abelian symmetries. The equations of motion that lead to the dual model are obtained for a general group, they depend in general on semi-chiral superfields; for cases such as SU(2) they depend on twisted chiral superfields. We solve the equations of motion for an SU(2) gauged group with a choice of a particular Lie algebra direction of the vector superfield. This direction covers a non-Abelian sector that can be described by a family of Abelian dualities. The dual model Lagrangian depends on twisted chiral superfields and a twisted superpotential is generated. We explore some non-perturbative aspects by making an Ansatz for the instanton corrections in the dual theories. We verify that the effective potential for the U(1) field strength in a fixed configuration on the original theory matches the one of the dual theory. Imposing restrictions on the vector superfield, more general non-Abelian dual models are obtained. We analyze the dual models via the geometry of their susy vacua.

Phenomenology of the SU(3)cxSU(3)LxU(1)X model with exotic charged leptons

International Nuclear Information System (INIS)

Salazar, Juan C.; Ponce, William A.; Gutierrez, Diego A.

2007-01-01

A phenomenological analysis of the three-family model based on the local gauge group SU(3) c xSU(3) L xU(1) X with exotic charged leptons, is carried out. Instead of using the minimal scalar sector able to break the symmetry in a proper way, we introduce an alternative set of four Higgs scalar triplets, which combined with an anomaly-free discrete symmetry, produce quark and charged lepton mass spectrum without hierarchies in the Yukawa coupling constants. We also embed the structure into a simple gauge group and show some conditions to achieve a low energy gauge coupling unification, avoiding possible conflict with proton decay bounds. By using experimental results from the CERN-LEP, SLAC linear collider, and atomic parity violation data, we update constraints on several parameters of the model

Correlation of the ghost and the quark in the lattice Landau gauge QCD

International Nuclear Information System (INIS)

Furui, Sadataka; Nakajima, Hideo

2007-01-01

Effects of the quark field on the ghost propagator of the lattice Landau gauge are investigated by using the unquenched SU(3) configurations produced by the MILC collaboration and compared with quenched gauge configurations of SU(2) first copy of the over relaxation gauge fixing, the parallel tempering (PT) gauge fixing and quenched SU(3) 56 4 configurations. We measure the color symmetric and the color antisymmetric ghost propagator and the Binder cumulant of the l 1 norm and the l 2 norm of color antisymmetric ghost propagators and investigate deviation from those of Gaussian distributions. In the first copy samples of quenched SU(2) we observe a large fluctuation in the Binder cumulant at the lowest momentum point. This fluctuation is reduced in the P T gauge fixed samples. The color anti-symmetric ghost propagator of quenched SU(3) configurations depends on the lattice size and is small as compared to the symmetric one in the large lattice of 56 4 . The Binder cumulant of the quenched SU(2) and the N f = 2 + 1 unquenched SU(3) are almost consistent with 3-d and 8-d Gaussian distribution, respectively. A comparison of the SU(3) unquenched configurations and quenched configurations indicates that the dynamical quarks have the effect of making color antisymmetric ghost propagator closer to the Gaussian distribution and the Kugo-Ojima color confinement parameter c closer to 1. (author)

Evaluation of physical constants and operators in the SU(2) and SU(3) lattice gauge theory

International Nuclear Information System (INIS)

Tsuchida, R.H.

1987-01-01

Wilson loops and Wilson lines in the fundamental and the adjoint representations of SU(2) on the lattice are measured using the icosahedral subgroup and a noise reduction technique. The string tension was evaluated by fitting the expectation value of loops of all sizes to a 6-parameter curve. From the Wilson lines in the adjoint representation of SU(2), two kinds of gluon potentials were measured: the gluon-gluon interaction potential and the gluon-image interaction potential. The effective mass of the gluon was evaluated on each of those potentials and compared. In SU(3), the contribution of s anti σ/sub μnu/F/sub μnu/d operator to the correction of effective weak four-quark operator in the measurement of ΔI = 1/2 amplitude of kaon decay is examined. The renormalization of the critical hopping parameter is calculated perturbatively and compared with the Monte Carlo results. The VEV of psi anti psi operator is measured on the lattice. In the hopping parameter renormalization calculation and the psi anti psi measurements, the effects of expanding of Feynman diagrams in power of a, the lattice spacing, are examined

The flipped SU(5)xU(1) string model revamped

Energy Technology Data Exchange (ETDEWEB)

Antoniadis, I.; Ellis, J.; Hagelin, J.S.; Nanopoulos, D.V. (European Organization for Nuclear Research, Geneva (Switzerland))

1989-11-02

We present a refined version of our three-generation flipped SU(5)xU(1) string model with the following properties. The complete massless spectrum is derived and shown to be free of all gauge and mixed anomalies apart from a single anomalous U(1). The imaginary part of the dilaton supermultiplet is eaten by the anomalous U(1) gauge boson, and the corresponding D-term is cancelled by large VEVs for singlet fields that break surplus U(1) gauge factors, leaving a supersymmetric vacuum with an SU(5)xU(1) visible gauge group and an SO(10)xSO(6) hidden gauge group. There are sufficient Higgs multiplets to break the visible gauge symmetry down to the standard model in an essentially unique way. All trilinear superpotential couplings have been calculated and there are in particular some giving m{sub t}, m{sub b}, m{sub tau}ne0. A renormalization group analysis shows that m{sub t}<190 GeV and m{sub b}{approx equal}3m{sub tau}. Light Higgs doublets are split automatically from heavy Higgs triplets, leaving no residual dimension-five operators for baryon decay, and the baryon lifetime tau{sub B} {approx equal} 2x10{sup 34{plus minus}2} yr. There are no tree-level flavour-changing neutral currents, but muyieldsegamma may occur at a detectable level: B(muyieldsegamma){proportional to} 10{sup -11}-10{sup -14}. (orig.).

Perturbative expansion of Chern-Simons theory with non-compact gauge group

International Nuclear Information System (INIS)

Bar-Natan, D.; Witten, E.

1991-01-01

Naive imitation of the usual formulas for compact gauge group in quantizing three dimensional Chern-Simons gauge theory with non-compact gauge group leads to formulas that are wrong or unilluminating. In this paper, an appropriate modification is described, which puts the perturbative expansion in a standard manifestly 'unitary' format. The one loop contributions (which differ from naive extrapolation from the case of compact gauge group) are computed, and their topological invariance is verified. (orig.)

Class of very simple gauge theories which remain renormalizable even in the limit of infinite gauge coupling constant

International Nuclear Information System (INIS)

Kaptanoglu, S.

1983-01-01

A class of local gauge theories based on compact semisimple Lie groups is studied in the limit of infinite gauge coupling constant (g = infinity). In general, in this limit, the gauge fields become auxiliary in all gauge theories, and the system develops a richer structure of constraints. Unfortunately for most gauge theories, this limit turns out to be too singular to quantize and the theory ceases to be renormalizable. For a special class of gauge theories, however, where there are no fermions and there is only one multiplet of scalars in the adjoint representation, we prove that a consistent renormalizable quantum theory exists even in this very singular limit. We trace this exceptional behavior to a new local translationlike symmetry in the functional space that this class of gauge models possesses in the limit of infinite gauge coupling constant. By carrying out the constraint analysis, evaluating the Faddeev-Popov-Senjanovic determinant, and doing the functional integrations over the canonical momenta, the gauge fields, and most of the components of the scalar fields, we obtain an extremely simple result with no non-Abelian structure left in it. For example, for the group SU(2), the final answer reduces to the theory of a one-component self-interacting real phi 4 scalar field theory. Throughout this paper, we use functional methods and make no approximations; our results are nonperturbative and exact. We also discuss some of the possible implications of our results

Reconstruction of the spontaneously broken gauge theory in non-commutative geometry

International Nuclear Information System (INIS)

Okumura, Y.; Morita, K.

1996-01-01

The scheme previously proposed by the present authors is modified to incorporate the strong interaction by affording the direct product internal symmetry. The authors do not need to prepare the extra discrete space for the colour gauge group responsible for the strong interaction to reconstruct the standard model and the left-right symmetric gauge model (LRSM). The approach based on non-commutative geometry leads us to present many attractive points such as the unified picture of the gauge and Higgs field as the generalized connection on the discrete space M 4 x Z N . This approach leads to unified picture of gauge and Higgs fields as the generalized connection. The standard model needs N=2 discrete space for reconstruction in this formalism. LRSM is still alive as a model with the intermediate symmetry of the spontaneously broken SO(10) grand unified theory (GUT). N=3 discrete space is needed for the reconstruction of LRSM to include two Higgs φ and ξ bosons usual transformed as (2, 2 * , 0) and (1, 3, -2) under SU(2) L x SU(2) R x U(1) Y , respectively. ξ is responsible to make v R Majorana fermion and so well explains the seesaw mechanism. Up and down quarks have different masses through the vacuum expectation value of φ

SU(2) Chern-Simons theory at genus zero

International Nuclear Information System (INIS)

Gawedzki, K.; Kupiainen, A.

1991-01-01

We present a detailed study of the Schroedinger picture space of states in the SU(2) Chern-Simons topological gauge theory in the simplest geometry. The space coincides with that of the solutions of the chiral Ward identities for the WZW model. We prove that its dimension is given by E. Verlinde's formulae. (orig.)

QCD gauge symmetries through Faddeev-Jackiw symplectic method

International Nuclear Information System (INIS)

Abreu, E.M.C.; Mendes, A.C.R.; Neves, C.; Oliveira, W.; Silva, R.C.N.

2013-01-01

Full text: The FJ method is an approach that is geometrically motivated. It is based on the symplectic structure of the phase space. The first-order characteristic allows to obtain the Hamiltonian equations of motion from a variational principle. Its geometric structure of the Hamiltonian phase-space will be carried out directly from the equations of motion via the inverse of the so-called symplectic two-form, if the inverse exists. Few years after its publication, the FJ formalism was extended and through the years it has been applied to different systems. Gauge invariance is one of the most well established concepts in theoretical physics and it is one of the main ingredients in Standard Model theory. However, we can ask if it could have an alternative origin connected to another theory or principle. With this motivation in mind we will show in this paper that gauge invariance could be considered an emergent concept having its origin in the algebraic formalism of a well known method that deals with constrained systems, namely, the Faddeev-Jackiw (FJ) technique. Of course the gauge invariance idea is older than FJ's, but the results obtained here will show that the connection between both will prove that SU(3) and SU(3) X SU(2) X U(1) gauge groups, which are fundamental to important theories like QCD and Standard Model, can be obtained through FJ formalism. (author)

SU(2) Yang-Mills solitons in R2 gravity

Science.gov (United States)

Perapechka, I.; Shnir, Ya.

2018-05-01

We construct new family of spherically symmetric regular solutions of SU (2) Yang-Mills theory coupled to pure R2 gravity. The particle-like field configurations possess non-integer non-Abelian magnetic charge. A discussion of the main properties of the solutions and their differences from the usual Bartnik-McKinnon solitons in the asymptotically flat case is presented. It is shown that there is continuous family of linearly stable non-trivial solutions in which the gauge field has no nodes.

Blockspin and multigrid for staggered fermions in non-abelian gauge fields

International Nuclear Information System (INIS)

Kalkreuter, T.; Mack, G.; Speh, M.

1991-07-01

We discuss blockspins for staggered fermions, i.e. averaging and interpolation procedures which are needed in a real space renormalization group approach to gauge theories with staggered fermions and in a multigrid approach to the computation of gauge covariant propagators. The discussion starts from the requirement that the symmetries of the free action should be preserved by the blocking procedure in the limit of a pure gauge. A definition of an averaging kernel as a solution of a gauge covariant eigenvalue equation is proposed, and the properties of a corresponding interpolation kernel are examined in the light of general criteria for good choices of blockspins. Some results of multigrid computation of bosonic propagation in an SU(2) gauge field in 4 dimensions are also presented. (orig.)

MS-on-shell quark mass relation up to four loops in QCD and a general SU(N) gauge group

International Nuclear Information System (INIS)

Marquard, Peter; Smirnov, Alexander V.; Smirnov, Vladimir A.; Steinhauser, Matthias; Wellmann, David

2016-06-01

In this paper we compute the relation between heavy quark masses defined in the modified minimal subtraction and on-shell scheme. Detailed results are presented for all coefficients of the SU(N_c) colour factors. The reduction of the four-loop on-shell integrals is performed for a general QCD gauge parameter. Some of the about 380 master integrals are computed analytically, others with high numerical precision based on Mellin-Barnes representations, and the rest numerically with the help of FIESTA. We discuss in detail the precise numerical evaluation of the four-loop master integrals. Updated relations between various short-distance masses and the MS quark mass to next-to-next-to-next-to-leading order accuracy are provided for the charm, bottom and top quark. We discuss the dependence on the renormalization and factorization scale.

Coherent states related with SU(N) and SU(N,1) groups

International Nuclear Information System (INIS)

Gitman, D.M.; Shelepin, A.L.

1990-01-01

The basis of coherent state (CS) for symmetric presentations of groups SU(N) and SU(N,1) is plotted, its properties being investigated. Evolution of CS is considered. Relation between CS of groups SU(N) and Glauber is ascertained

Cosmic string in compactified gauge theory

International Nuclear Information System (INIS)

Nakamura, A.; Hirenzaki, S.; Shiraishi, K.

1989-08-01

A solution of the vortex type is given in a six-dimensional SU(2)xU(1) pure gauge theory coupled to Einstein gravity in a compactified background geometry. We construct the solution of an effective Abelian-Higgs model in terms of dimensional reduction. The solution, however, has a peculiarity in its physically relevant quantity, a deficit angle, which is given as a function of the ratio of the gauge couplings of SU(2) and U(1). The size of the extra space (sphere) is shown to vary with the distance from the axis of the 'string'. (author)

Gauge theories on a small lattice

International Nuclear Information System (INIS)

Robson, D.; Webber, D.M.

1980-01-01

We present exact solutions to U(1), SU(2), and SU(3) lattice gauge theories on a Kogut-Susskind lattice consisting of a single plaquette. We demonstrate precise equivalence between the U(1) theory and the harmonic oscillator on an infinite one-dimensional lattice, and between the SU(N) theory and an N-fermion Schroedinger equation. (orig.)

Gauge-invariant variational methods for Hamiltonian lattice gauge theories

International Nuclear Information System (INIS)

Horn, D.; Weinstein, M.

1982-01-01

This paper develops variational methods for calculating the ground-state and excited-state spectrum of Hamiltonian lattice gauge theories defined in the A 0 = 0 gauge. The scheme introduced in this paper has the advantage of allowing one to convert more familiar tools such as mean-field, Hartree-Fock, and real-space renormalization-group approximation, which are by their very nature gauge-noninvariant methods, into fully gauge-invariant techniques. We show that these methods apply in the same way to both Abelian and non-Abelian theories, and that they are at least powerful enough to describe correctly the physics of periodic quantum electrodynamics (PQED) in (2+1) and (3+1) space-time dimensions. This paper formulates the problem for both Abelian and non-Abelian theories and shows how to reduce the Rayleigh-Ritz problem to that of computing the partition function of a classical spin system. We discuss the evaluation of the effective spin problem which one derives the PQED and then discuss ways of carrying out the evaluation of the partition function for the system equivalent to a non-Abelian theory. The explicit form of the effective partition function for the non-Abelian theory is derived, but because the evaluation of this function is considerably more complicated than the one derived in the Abelian theory no explicit evaluation of this function is presented. However, by comparing the gauge-projected Hartree-Fock wave function for PQED with that of the pure SU(2) gauge theory, we are able to show that extremely interesting differences emerge between these theories even at this simple level. We close with a discussion of fermions and a discussion of how one can extend these ideas to allow the computation of the glueball and hadron spectrum

On the SU(2)× SU(2) symmetry in the Hubbard model

Science.gov (United States)

Jakubczyk, Dorota; Jakubczyk, Paweł

2012-08-01

We discuss the one-dimensional Hubbard model, on finite sites spin chain, in context of the action of the direct product of two unitary groups SU(2)× SU(2). The symmetry revealed by this group is applicable in the procedure of exact diagonalization of the Hubbard Hamiltonian. This result combined with the translational symmetry, given as the basis of wavelets of the appropriate Fourier transforms, provides, besides the energy, additional conserved quantities, which are presented in the case of a half-filled, four sites spin chain. Since we are dealing with four elementary excitations, two quasiparticles called "spinons", which carry spin, and two other called "holon" and "antyholon", which carry charge, the usual spin- SU(2) algebra for spinons and the so called pseudospin-SU(2) algebra for holons and antiholons, provide four additional quantum numbers.

Phases of renormalized lattice gauge theories with fermions

International Nuclear Information System (INIS)

Caracciolo, S.; Menotti, P.; and INFN Sezione di Pisa, Italy)

1979-01-01

Starting from the formulation of gauge theories on a lattice we derive renormalization group transformation of the Migdal-Kadanoff type in the presence of fermions. We consider the effect of the fermion vacuum polarization on the gauge Lagrangian but we neglect fermion mass renormalization. We work out the weak coupling and strong coupling expansion in the same framework. Asymptotic freedom is recovered for the non-Abelian case provided the number of fermion multiplets is lower than a critical number. Fixed points are determined both for the U (1) and SU (2) case. We determine the renormalized trajectories and the phases of the theory

General treatment of a non-linear gauge condition

International Nuclear Information System (INIS)

Malleville, C.

1982-06-01

A non linear gauge condition is presented in the frame of a non abelian gauge theory broken with the Higgs mechanism. It is shown that this condition already introduced for the standard SU(2) x U(1) model can be generalized for any gauge model with the same type of simplification, namely the suppression of any coupling of the form: massless gauge boson, massive gauge boson, unphysical Higgs [fr

Monte Carlo studies of non-Abelian gauge theories

International Nuclear Information System (INIS)

Creutz, M.

1980-05-01

After some general remarks on the efficiency of various Monte Carlo algorithms for gauge theories, the calculation of the asymptotic freedom scales of SU(2) and SU(3) gauge theories in the absence of quarks was discussed. There are large numerical factors between these scales when defined in terms of the bare coupling of the lattice theory or when defined in terms of the physical force between external sources

SU(2) x U(1) unified theory for charge, orbit and spin currents

International Nuclear Information System (INIS)

Jin Peiqing; Li Youquan; Zhang Fuchun

2006-01-01

Spin and charge currents in systems with Rashba or Dresselhaus spin-orbit couplings are formulated in a unified version of four-dimensional SU(2) x U(1) gauge theory, with U(1) being the Maxwell field and SU(2) being the Yang-Mills field. While the bare spin current is non-conserved, it is compensated by a contribution from the SU(2) gauge field, which gives rise to a spin torque in the spin transport, consistent with the semi-classical theory of Culcer et al. Orbit current is shown to be non-conserved in the presence of electromagnetic fields. Similar to the Maxwell field inducing forces on charge and charge current, we derive forces acting on spin and spin current induced by the Yang-Mills fields such as the Rashba and Dresselhaus fields and the sheer strain field. The spin density and spin current may be considered as a source generating Yang-Mills field in certain condensed matter systems

Phenomenology of the SU(3)c x SU(3)L x U(1)X model with right-handed neutrinos

International Nuclear Information System (INIS)

Gutierrez, D.A.; Ponce, W.A.; Sanchez, L.A.

2006-01-01

A phenomenological analysis of the three-family model based on the local gauge group SU(3) c x SU(3) L x U(1) X with right-handed neutrinos is carried out. Instead of using the minimal scalar sector able to break the symmetry in a proper way, we introduce an alternative set of four Higgs scalar triplets, which combined with an anomaly-free discrete symmetry, produces a quark mass spectrum without hierarchies in the Yukawa coupling constants. We also embed the structure into a simple gauge group and show some conditions for achieving a low energy gauge coupling unification, avoiding possible conflict with proton decay bounds. By using experimental results from the CERN-LEP, SLAC linear collider, and atomic parity violation data, we update constraints on several parameters of the model. (orig.)

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)

Gauge-fixing ambiguity and monopole number

International Nuclear Information System (INIS)

Hioki, S.; Miyamura, O.

1991-01-01

Gauge-fixing ambiguities of lattice SU(2) QCD are studied in the maximally abelian and unitary gauges. In the former, we find local maxima of a gauge-fixing function which may correspond to Gribov copies. There is a definite anti-correlation between the number of monopoles and the value of the function. Errors of measured quantities coming from the ambiguity are found to be less than inherent dispersion in the ensemble average. No ambiguity is found in the unitary gauges. (orig.)

Renormalisation group behaviour of O+ and 2+ glueball masses in SU(2) lattice gauge theory

International Nuclear Information System (INIS)

Ishikawa, K.; Schierholz, G.

1982-07-01

We calculate the 0 + and 2 + glueball masses at several values of the coupling and verify compatibility with the desired renormalisation group behaviour. The calculation uses momentum smeared glueball wave functions on a large 8 4 lattice and confirms our previous results obtained on smaller lattices. (orig.)

arXiv Global $SU(2)_L \\otimes$BRST symmetry and its LSS theorem: Ward-Takahashi identities governing Green's functions, on-shell T-Matrix elements, and $V_{eff}$, in the scalar-sector of certain spontaneously broken non-Abelian gauge theories

CERN Document Server

Güngör, Özenç; Starkman, Glenn D.; Stora, Raymond

This work is dedicated to the memory of Raymond Stora (1930-2015). $SU(2)_L$ is the simplest spontaneous symmetry breaking (SSB) non-Abelian gauge theory: a complex scalar doublet $\\phi=\\frac{1}{\\sqrt{2}}\\begin{bmatrix}H+i\\pi_3-\\pi_2 +i\\pi_1\\end{bmatrix}\\equiv\\frac{1}{\\sqrt{2}}\\tilde{H}e^{2i\\tilde{t}\\cdot\\tilde{\\vec{\\pi}}/}\\begin{bmatrix}10\\end{bmatrix}$ and a vector $\\vec{W}^\\mu$. In Landau gauge, $\\vec{W}^\\mu$ is transverse, $\\vec{\\tilde{\\pi}}$ are massless derivatively coupled Nambu-Goldstone bosons (NGB). A global shift symmetry enforces $m^{2}_{\\tilde{\\pi}}=0$. We observe that on-shell T-matrix elements of physical states $\\vec{W}^\\mu$,$\\phi$ are independent of global $SU(2)_{L}$ transformations, and the associated global current is exactly conserved for amplitudes of physical states. We identify two towers of "1-soft-pion" global Ward-Takahashi Identities (WTI), which govern the $\\phi$-sector, and represent a new global symmetry, $SU(2)_L\\otimes$BRST, a symmetry not of the Lagrangian but of the physical...

String threshold corrections and flipped SU(5)

Energy Technology Data Exchange (ETDEWEB)

Antoniadis, I. (Ecole Polytechnique, Centre de Physique Theorique, 91 - Palaiseau (France) Theory Div., CERN, Geneva (Switzerland)); Ellis, J. (Theory Div., CERN, Geneva (Switzerland)); Lacaze, R. (Service de Physique Theorique, CEN-Saclay, 91 - Gif-sur-Yvette (France)); Nanopoulos, D.V. (Center for Theoretical Physics, Dept. of Physics, Texas A and M Univ., College Station, TX (United States) Astroparticle Physics Group, HARC, The Woodlands, TX (United States) Theory Div., CERN, Geneva (Switzerland))

1991-10-10

We revise previous calculations of the effective unification scale m{sub SU} at which the extrapolated low-energy gauge couplings should appear to become equal, and we show explicitly how to calculate m{sub SU} in the fermionic construction of four-dimensional strings. In the case of the flipped SU(5) GUT derived from the string, the SU(5) and U(1) couplings defined in the anti Danti R scheme become equal to g{sub SU} at m{sub SU} {approx equal} 1.76 x g{sub SU} x 10{sup 18} GeV. This scale is significantly larger than m{sub GUT}, the scale at which the low-energy SU(3) and SU(2) couplings become equal if extrapolated using the renormalization group equations of the minimal supersymmetric extension of the standard model. The existence of an intermediate SU(5) x U(1) phase could have an observable effect on the calculated value of sin{sup 2}{theta}{sub w}. (orig.).

Phase structure and confinement properties of noncompact gauge theories: Z(N) Wilson loop and effective noncompact model

International Nuclear Information System (INIS)

Borisenko, O.A.; Petrov, V.K.; Zinovjev, G.M.; Bohacik, J.

1997-01-01

An approach to studying lattice gauge models in the weak-coupling region is proposed. Conceptually, this approach is based on the crucial role of original Z(N) symmetry and of the invariant gauge-group measure. As an example, an effective model from the compact Wilson formulation of SU(2) gauge theory is calculated in d=3 dimensions at zero temperature. The confining properties and the phase structure of the effective model are studied in detail

Potentials in N=2 supergravity

International Nuclear Information System (INIS)

Zinov'ev, Yu.M.

1985-01-01

The potentials and Yukava interactions, that arise while introducing a gauge interaction of vector and scalar multiplets in N=2 supergravity are presented, in this the gauge group may be either compact or noncompact. The scalar multiplets geometry corresponds to nonlinear σ, models of the form Sp(2,2n)/Sp(2)xSp(2n), SU(2,n)/SU(2)SU(n)xU(1) and O(4,n)/O(4)xO(n)

Extended tree-level gauge mediation

DEFF Research Database (Denmark)

Monaco, M.; Nardecchia, M.; Romanino, A.

2011-01-01

Tree-level gauge mediation (TGM) is a scenario of SUSY breaking in which the tree-level exchange of heavy (possibly GUT) vector fields generates flavor-universal sfermion masses. In this work we extend this framework to the case of E(6) that is the natural extension of the minimal case studied so...... if the gauge group does not contain SU(5). If SUSY breaking is mediated purely by the U(1) generator that commutes with SO(10) we obtain universal sfermion masses and thus can derive the CMSSM boundary conditions in a novel scenario....

Parity violations in electron-nucleon scattering and the SU(2)sub(L)xSU(2)sub(R)xU(1)sub(L+R) electroweak symmetry

International Nuclear Information System (INIS)

Rajpoot, S.

1981-07-01

The SU(2)sub(L) x SU(2)sub(R) x U(1)sub(L+R) model of electroweak interactions is described with the most general gauge couplings gsub(L), gsub(R) and gsub(L+R). The case in which neutrino neutral current interactions are identical to the standard SU(2)sub(L) x U(1)sub(L+R) model is discussed in detail. It is shown that with the weak angle lying in the experimental range sin 2 thetaSUB(w)=0.23+-0.015 and 1 2 /gsub(R) 2 <3 it is possible to explain the amount of parity violation observed at SLAC and at the same time predict values of the ''weak charge'' in bismuth to lie in the range admitted by the controversal data from different experiments. (author)

Information on the gauge principle from an N=1/2, D=2 supersymmetric model

International Nuclear Information System (INIS)

Dias, S.A.; Doria, R.M.; Valle, J.L.M.

1988-01-01

The gauge principle does not only work to generate interactions. It potentially yields an abundance of gauge-potential fields transforming under the same local symmetry group. In order to show evidences of this property this work gauge-covariantizes an N = 1/2, D = 2 supersymmetric theory. Then, by relaxing the so-called conventional constraint, a second gauge-potential field naturally emerges. (author) [pt

Fractal dimension of the topological charge density distribution in SU(2) lattice gluodynamics

International Nuclear Information System (INIS)

Buividovich, P.V.; Kalaydzhyan, T.; Polikarpov, M.I.

2011-11-01

We study the effect of cooling on the spatial distribution of the topological charge density in quenched SU(2) lattice gauge theory with overlap fermions. We show that as the gauge field configurations are cooled, the Hausdorff dimension of regions where the topological charge is localized gradually changes from d=2/3 towards the total space dimension. Hence the cooling procedure destroys some of the essential properties of the topological charge distribution. (orig.)

Fractal dimension of the topological charge density distribution in SU(2) lattice gluodynamics

Energy Technology Data Exchange (ETDEWEB)

Buividovich, P.V. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Institute for Theoretical and Experimental Physics ITEP, Moscow (Russian Federation); Kalaydzhyan, T. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Institute for Theoretical and Experimental Physics ITEP, Moscow (Russian Federation); Polikarpov, M.I. [Institute for Theoretical and Experimental Physics ITEP, Moscow (Russian Federation)

2011-11-15

We study the effect of cooling on the spatial distribution of the topological charge density in quenched SU(2) lattice gauge theory with overlap fermions. We show that as the gauge field configurations are cooled, the Hausdorff dimension of regions where the topological charge is localized gradually changes from d=2/3 towards the total space dimension. Hence the cooling procedure destroys some of the essential properties of the topological charge distribution. (orig.)

Topological susceptibility near Tc in SU(3 gauge theory

Directory of Open Access Journals (Sweden)

Guang-Yi Xiong

2016-01-01

Full Text Available Topological charge susceptibility χt for pure gauge SU(3 theory at finite temperature is studied using anisotropic lattices. The over-improved stout-link smoothing method is utilized to calculate the topological charge. Near the phase transition point we find a rapid declining behavior for χt with values decreasing from (188(1 MeV4 to (67(3 MeV4 as the temperature increased from zero temperature to 1.9Tc which demonstrates the existence of topological excitations far above Tc. The 4th order cumulant c4 of topological charge, as well as the ratio c4/χt is also investigated. Results of c4 show step-like behavior near Tc while the ratio at high temperature agrees with the value as predicted by the diluted instanton gas model.

Screening masses in the SU(3) pure gauge theory and universality

International Nuclear Information System (INIS)

Falcone, R.; Fiore, R.; Gravina, M.; Papa, A.

2007-01-01

We determine from Polyakov loop correlators the screening masses in the deconfined phase of the (3+1)d SU(3) pure gauge theory at finite temperature near the transition, for two different channels of angular momentum and parity. Their ratio is compared with that of the massive excitations with the same quantum numbers in the 3d 3-state Potts model in the broken phase near the transition point at zero magnetic field. Moreover we study the inverse decay length of the correlation between the real parts and between the imaginary parts of the Polyakov loop and compare the results with expectations from perturbation theory and mean-field Polyakov loop models

Studies on representation of the Lorentz group and gauge theory

International Nuclear Information System (INIS)

Hanitriarivo, R.

2002-01-01

This work is focused on studies about the representation of the Lorentz group and gauge theory. The mathematical tools required for the different studies are presented, as well as for the representation of the Lorentz group and for the gauge theory. Representation of the Lorentz group gives the possible types of fields and wave functions that describe particles: fermions are described by spinors and bosons are described by scalar or vector. Each of these entities (spinors, scalars, vectors) are characterized by their behavior under the action of Lorentz transformations.Gauge theory is used to describe the interactions between particles. [fr

M2-brane surface operators and gauge theory dualities in Toda

International Nuclear Information System (INIS)

Gomis, Jaume; Floch, Bruno Le

2016-01-01

We give a microscopic two dimensional N=(2,2) gauge theory description of arbitrary M2-branes ending on N _f M5-branes wrapping a punctured Riemann surface. These realize surface operators in four dimensional N=2 field theories. We show that the expectation value of these surface operators on the sphere is captured by a Toda CFT correlation function in the presence of an additional degenerate vertex operator labelled by a representation R of SU(N _f), which also labels M2-branes ending on M5-branes. We prove that symmetries of Toda CFT correlators provide a geometric realization of dualities between two dimensional gauge theories, including N=(2,2) analogues of Seiberg and Kutasov-Schwimmer dualities. As a bonus, we find new explicit conformal blocks, braiding matrices, and fusion rules in Toda CFT.

T-expansion and its application to SU(2) lattice gauge theory

International Nuclear Information System (INIS)

Karliner, M.

1984-01-01

A scheme allowing systematic improvement of variational calculations has been developed at SLAC. This paper contains an outline of the method, as well as some preliminary results of its application to two dimensional spin systems and four dimensional SU(2) lattice guage theory

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...

Reducing the rank of gauge groups in orbifold compactification

International Nuclear Information System (INIS)

Sato, H.

1989-01-01

The Wilson-line mechanism in orbifold compactification is investigated for both Abelian and non-Abelian embedding of the Z 3 group in the E 8 x E 8 . The authors give general argument in the fermionic formulation for the gauge degrees of freedom and show that the rank of the gauge group is reduced by introducing nondiagonal Wilson-line matrix in the fermionic boundary conditions

On the gauge orbit space stratification: a review

International Nuclear Information System (INIS)

Rudolph, G.; Schmidt, M.; Volobuev, I.P.

2002-01-01

First, we review the basic mathematical structures and results concerning the gauge orbit space stratification. This includes general properties of the gauge group action, fibre bundle structures induced by this action, basic properties of the stratification and the natural Riemannian structures of the strata. In the second part, we study the stratification for theories with gauge group SU(n) in spacetime dimension 4. We develop a general method for determining the orbit types and their partial ordering, based on the 1-1 correspondence between orbit types and holonomy-induced Howe subbundles of the underlying principal SU(n)-bundle. We show that the orbit types are classified by certain cohomology elements of spacetime satisfying two relations and that the partial ordering is characterized by a system of algebraic equations. Moreover, operations for generating direct successors and direct predecessors are formulated, which allow one to construct the set of orbit types, starting from the principal type. Finally, we discuss an application to nodal configurations in Yang-Mills-Chern-Simons theory. (author)

Study of unique trajectories in SU(2) and SU(3) lattice Gauge theories

International Nuclear Information System (INIS)

Nerses, Hudaverdian

1985-01-01

As is well known, in the context of quantum field theories describing different types of interactions in the domain of particle physics, there are rampant ultraviolet infinite which are subtly taken care of by adequate renormalization procedures. The most conventional perturbative regularization schemes are based on the Feynman expansion, so successfully used in quantum electrodynamics. But the unique feature of confinement in strong interactions has forced physicists to search for a non-perturbative cut-off, and this has been provided by the introduction of discrete spacetime lattices over which the field theories have been formulated. the lattice represents a mathematical trick, a more scaffolding, an intermediate step, used to analyze a difficult non-linear system, of an infinite number of degree of freedom. Herein lies the main virtue of the lattice, which directly eliminates all wavelengths less than twice the lattice spacing.Consequently, regarding the lattice merely as an ultraviolet cut-off, physicists should remove this regulator and expect observable quantities to approach their physical values. However as the removal of the regulator is discussed, the question of renormalization emerges, and it is here that the Migdal-Kadanoff recursion relations, representing a simple approximate method for comparing theories with different lattice spacings bring in their virtue by providing a simple method for obtaining an approximate renormalization group function. It is hoped, and currently extensively investigated whether the Migdal renormalization group approach, combined with some other methods, can really provide useful information on the phase structures of lattice gauge theories

A non-perturbative study of massive gauge theories

DEFF Research Database (Denmark)

Della Morte, Michele; Hernandez, Pilar

2013-01-01

and the lightest degrees of freedom are spin one vector particles with the same quantum numbers as the conserved current, we argue that the most general effective theory describing their low-energy dynamics must be a massive gauge theory. We present results of a exploratory numerical simulation of the model......We consider a non-perturbative formulation of an SU(2) massive gauge theory on a space-time lattice, which is also a discretised gauged non-linear chiral model. The lattice model is shown to have an exactly conserved global SU(2) symmetry. If a scaling region for the lattice model exists...... and find indications for the presence of a scaling region where both a triplet vector and a scalar remain light....

Mass anomalous dimension in SU(2) with six fundamental fermions

DEFF Research Database (Denmark)

Bursa, Francis; Del Debbio, Luigi; Keegan, Liam

2010-01-01

We simulate SU(2) gauge theory with six massless fundamental Dirac fermions. We measure the running of the coupling and the mass in the Schroedinger Functional scheme. We observe very slow running of the coupling constant. We measure the mass anomalous dimension gamma, and find it is between 0.13...

Loop calculus for lattice gauge theories

International Nuclear Information System (INIS)

Gambini, R.; Leal, L.; Trias, A.; Departamento de Fisica Aplicada, Facultad de Ingenieria, Universidad Central de Venezuela, Apartado 47724, Caracas 1051, Venezuela; Departament de Matematiques, Universitat Politecnica de Catalunya, Escuela Tecnica Superior de Enginyers de Telecomunicaciones, Barcelona 08034, Spain)

1989-01-01

Hamiltonian calculations are performed using a loop-labeled basis where the full set of identities for the SU(N) gauge models has been incorporated. The loops are classified as clusterlike structures and the eigenvalue problem leads to a linear set of finite-difference equations easily amenable to numerical treatment. Encouraging results are reported for SU(2) at spatial dimension 2

The gradient flow running coupling in SU2 with 8 flavors

DEFF Research Database (Denmark)

Rantaharju, Jarno; Karavirta, Tuomas; Leino, Viljami

2014-01-01

We present preliminary results of the gradient flow running coupling with Dirichlet boundary condition in the SU(2) gauge theory with 8 fermion flavours. Improvements to the gradient flow measurement allow us to obtain a robust continuum limit. The results are consistent with perturbative running...

Low-dimensional gravities as gauge theories with non-compact groups

International Nuclear Information System (INIS)

Cangeni, D.

1993-01-01

In another note presented in these Proceedings it is shown that the two main lineal gravities can be given a gauge formulation. If it is already known that one of them the Sitter model - is a dimensional reduction of a Chern-Simons model in (2+1) dimensions, it was not clear whether the other one - the extended Poincare model follows from a similar reduction. The purpose of this note is to show that this is indeed the case provide we start in 2+1 dimensions with an extension ISO(2,1) of the Poincare groups as gauge group of a Chern-Simons model. We first show that this model gives a new proposal for gravity in 2*1 dimensions, since we get classically the Einstein's equations. Performing then a dimensional reduction, we recover not only the extended Poincare model but also the de Sitter one; hence, both lineal gravities get unified in the reduced model. (Author) 6 refs

String tensions for lattice gauge theories in 2+1 dimensions

International Nuclear Information System (INIS)

Ambjoern, J.; Hey, A.J.G.; Otto, S.

1982-01-01

Compact U(1) and SU(2) lattice gauge theories in 3 euclidean dimensions are studied by standard Monte Carlo techniques. The question of extracting reliable string tensions from these theories is examined in detail, including a comparison of the Monte Carlo Wilson loop data with weak coupling predictions and a careful error analysis: our conclusions are rather different from those of previous investigations of these theories. In the case of U(1) theory, we find that only a tiny range of β values can possibly be relevant for extracting a string tension and we are unable to convincingly demonstrate the expected exponential dependence of the string tension on β. For the SU(2) theory we are able to determine, albeit with rather large errors, a string tension from a study of Wilson loops. (orig.)

Two potentials, one gauge group: A possible geometrical motivation

International Nuclear Information System (INIS)

Doria, R.M.; Pombo, C.

1985-01-01

By studying the purely gravitational sector of a higher dimensional matter-gravity coupled theory, one can see that in the case of non-vanishing torsion the effective 4-dimensional theory exhibits two gauge potentials that transform under the action of a single gauge group. (Author) [pt

Gauge-invariant scalar and field strength correlators in 3d

CERN Document Server

Laine, Mikko

1998-01-01

Gauge-invariant non-local scalar and field strength operators have been argued to have significance, e.g., as a way to determine the behaviour of the screened static potential at large distances, as order parameters for confinement, as input parameters in models of confinement, and as gauge-invariant definitions of light constituent masses in bound state systems. We measure such "correlators" in the 3d pure SU(2) and SU(2)+Higgs models on the lattice. We extract the corresponding mass parameters and discuss their scaling and physical interpretation. We find that the finite part of the MS-bar scheme mass measured from the field strength correlator is large, more than half the glueball mass. We also determine the non-perturbative contribution to the Debye mass in the 4d finite T SU(2) gauge theory with a method due to Arnold and Yaffe, finding $\\delta m_D\\approx 1.06(4)g^2T$.

Gauge field theory approach to spin transport in a 2D electron gas

Directory of Open Access Journals (Sweden)

B. Berche

2009-01-01

Full Text Available We discuss the Pauli Hamiltonian including the spin-orbit interaction within an U(1×SU(2 gauge theory interpretation, where the gauge symmetry appears to be broken. This interpretation offers new insight into the problem of spin currents in the condensed matter environment, and can be extended to Rashba and Dresselhaus spin-orbit interactions. We present a few outcomes of the present formulation: i it automatically leads to zero spin conductivity, in contrast to predictions of Gauge symmetric treatments, ii a topological quantization condition leading to voltage quantization follows, and iii spin interferometers can be conceived in which, starting from an arbitrary incoming unpolarized spinor, it is always possible to construct a perfect spin filtering condition.

Weak interactions and gauge theories

International Nuclear Information System (INIS)

Gaillard, M.K.

1979-12-01

The status of the electroweak gauge theory, also known as quantum asthenodynamics (QAD), is examined. The major result is that the standard WS-GIM model describes the data well, although one should still look for signs of further complexity and better tests of its gauge theory aspect. A second important result is that the measured values of the three basic coupling constants of present-energy physics, g/sub s/, g, and √(5/3)g' of SU(3)/sub c/ x SU(2) 2 x U(1), are compatible with the idea that these interactions are unified at high energies. Much of the paper deals with open questions, and it takes up the following topics: the status of QAD, the scalar meson spectrum, the fermion spectrum, CP violation, and decay dynamics. 118 references, 20 figures

An improved single-plaquette gauge action

International Nuclear Information System (INIS)

Banerjee, D.; Bögli, M.; Holland, K.; Niedermayer, F.; Pepe, M.; Wenger, University; Wiese, UniversityJ.

2016-01-01

We describe and test a nonperturbatively improved single-plaquette lattice action for 4-d SU(2) and SU(3) pure gauge theory, which suppresses large fluctuations of the plaquette, without requiring the naive continuum limit for smooth fields. We tune the action parameters based on torelon masses in moderate cubic physical volumes, and investigate the size of cut-off effects in other physical quantities, including torelon masses in asymmetric spatial volumes, the static quark potential, and gradient flow observables. In 2-d O(N) models similarly constructed nearest-neighbor actions have led to a drastic reduction of cut-off effects, down to the permille level, in a wide variety of physical quantities. In the gauge theories, we find significant reduction of lattice artifacts, and for some observables, the coarsest lattice result is very close to the continuum value. We estimate an improvement factor of 40 compared to using the Wilson gauge action to achieve the same statistical accuracy and suppression of cut-off effects.

Construction of U-gauge Green's functions of gauge theories with spontaneous symmetry breaking and Slavnov identities

International Nuclear Information System (INIS)

Flume, R.

1978-01-01

The unitary (U) gauge Green's functions of the U(1) and SU(2) Higgs-Kibble models are constructed applying a renormalized point transformation and a non-local gauge changing transformation to a manifestly renormalizable (R gauge) version of the respective theory. It is shown that the cancellation mechanism known as 'tree graph unitarity' rendering in tree graph approximation a smooth high energy behaviour of the U gauge Green's functions on mass shell can in a natural way be extended to all orders of perturbation theory. The conditions imposed by this 'generalized tree graph unitarity' on the renormalization programme are shown to be equivalent with the requirement of renormalized Slavnov identities for the R gauge Green's functions

Study of the zero modes of the Faddeev–Popov operator in the maximal Abelian gauge

International Nuclear Information System (INIS)

Capri, M.A.L.; Guimaraes, M.S.; Lemes, V.E.R.; Sorella, S.P.; Tedesco, D.G.

2014-01-01

A study of the zero modes of the Faddeev–Popov operator in the maximal Abelian gauge is presented in the case of the gauge group SU(2) and for different Euclidean space–time dimensions. Explicit examples of classes of normalizable zero modes and corresponding gauge field configurations are constructed by taking into account two boundary conditions, namely: (i) the finite Euclidean Yang–Mills action, (ii) the finite Hilbert norm. -- Highlights: •We study the zero modes of the Faddeev–Popov operator in the maximal Abelian gauge. •For d=2 we obtain solutions with finite action but not finite Hilbert norm. •For d=3,4 we obtain solutions with finite action and finite Hilbert norm. •These results can be compared with those previously obtained in the Landau gauge

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

Solution of the gauge hierarchy problem

International Nuclear Information System (INIS)

Dimopoulos, S.; Georgi, H.

1982-01-01

We propose a novel solution to the gauge hierarchy problem in theories with softly broken supersymmetry. Quantum effects can resuscitate classically sick theories, producing the large scale from the small supersymmetry breaking scale. We use this mechanism to construct realistic SU(6) and SU(5) GUTs which do not suffer from gauge hierarchy or fine tuning problems. (orig.)

The potentials of the gauged N=8 supergravity theories

International Nuclear Information System (INIS)

Hull, C.M.

1985-01-01

The potentials of the SO(p,q) gaugings of N=8 supergravity are investigated for critical points. The SO(7,1) gauging has no G 2 -invariant critical points, the SO(6,2) theory has no SU(3) invariant critical points and the SO(5,3) gauging has only one SO(5)-invariant critical point, with positive cosmological constant, SO(5) x SO(3) symmetry and no supersymmetry. (orig.)

Light third-generation squarks from flavour gauge messengers

International Nuclear Information System (INIS)

Brümmer, Felix; McGarrie, Moritz; Weiler, Andreas

2014-01-01

We study models of gauge-mediated supersymmetry breaking with a gauged horizontal SU(3) F symmetry acting on the quark superfields. If SU(3) F is broken non-supersymmetrically by F-term vacuum expectation values, the massive gauge bosons and gauginos become messengers for SUSY breaking mediation. These gauge messenger fields induce a flavour-dependent, negative contribution to the soft masses of the squarks at one loop. In combination with the soft terms from standard gauge mediation, one obtains large and degenerate first- and second-generation squark masses, while the stops and sbottoms are light. We discuss the implications of this mechanism for the superparticle spectrum and for flavour precision observables. We also provide an explicit realization in a model with simultaneous SUSY and SU(3) F breaking

Light third-generation squarks from flavour gauge messengers

International Nuclear Information System (INIS)

Bruemmer, Felix; McGarrie, Moritz; Univ. of the Witwatersrand, Johannesburg; Weiler, Andreas; CERN - European Organization for Nuclear Research, Geneva

2014-04-01

We study models of gauge-mediated supersymmetry breaking with a gauged horizontal SU(3) F symmetry acting on the quark superfields. If SU(3) F is broken non-supersymmetrically by F-term vacuum expectation values, the massive gauge bosons and gauginos become messengers for SUSY breaking mediation. These gauge messenger fields induce a flavour-dependent, negative contribution to the soft masses of the squarks at one loop. In combination with the soft terms from standard gauge mediation, one obtains large and degenerate first- and second-generation squark masses, while the stops and sbottoms are light. We discuss the implications of this mechanism for the superparticle spectrum and for flavour precision observables. We also provide an explicit realization in a model with simultaneous SUSY and SU(3) F breaking.

Width and string tension of the flux tube in SU(2) lattice gauge theory at high temperature

Science.gov (United States)

Chagdaa, S.; Galsandorj, E.; Laermann, E.; Purev, B.

2018-02-01

We study the profiles of the flux tube between a static quark and an antiquark in quenched SU(2) lattice gauge theory at temperatures around the deconfinement phase transition. The physical width of the flux tube and the string tension have been determined from the transverse profiles and the q\\bar{q} potential, respectively. Exploiting the computational power of a GPU accelerator in our flux tube investigation, we achieve much higher statistics through which we can increase the signal to noise ratio of our observables in the simulation. This has allowed the investigation of larger lattices as well as larger separations between the quarks than in our previous work. The improved accuracy gives us better results for the width and the string tension. The physical width of the flux tube increases with the temperature up to around T c while keeping its increasing dependence on the q\\bar{q} separation. The string tension results are compared for two different sizes of the lattice. As the lattice becomes larger and finer together with the improved precision, the temperature dependent string tension tends to have a smaller value than the previous one.

SU(5) monopoles, magnetic symmetry and confinement

International Nuclear Information System (INIS)

Daniel, M.; Lazarides, G.; Shafi, Q.

1980-01-01

The monopoles of the unified SU(5) gauge theory broken down to Hsub(E) = SU(3)sub(c) x U(1)sub(EM) [or to Ksub(E) = SU(3)sub(c) x SU(2) x U(1)sub(γ)], are classified. They belong to representations of a magnetic group Hsub(M)(Ksub(M)), which is found to be isomorphic to Hsub(E)(Ksub(E)). For SU(5) broken down to Hsub(E), there exists a regular and stable monopole which is a colour magnetic triplet, and carries a non-zero abelian magnetic charge. It is suggested that composite operators made out of this monopole and its antiparticle fields develop a non-zero vacuum expectation value, and so lead to a squeezing of the colour electric flux. Finally, we comment on the cosmological production of SU(5) monopoles. (orig.)

Symmetry breaking by Wilson loops in gauge field theory

International Nuclear Information System (INIS)

Dowker, J.S.; Jadhav, S.P.

1989-01-01

An analysis is presented of the gauge symmetry breaking caused by Wilson loops on a space-time whose spatial section is openR/sup d/ x S 3 /Γ, for all those fundamental groups Γ that give a homogeneous space. We concentrate on pure SU(3) and SU(5) gauge field theories and find that symmetry breaking can occur when d = 0, for all Γ. If d = 3, the extra minimal scalars prevent any breaking and one must include other fields to achieve this. Explicit forms for the vacuum energies are exhibited in the case of lens and prism spaces, the former for SU(n). For Γ = Z/sub m/, when m and the radius of the sphere become infinite, we recover the results on the space-time openR/sup d//sup +3/ x S 1

A relativistic gauge model describing N particles bound by harmonic forces

International Nuclear Information System (INIS)

Filippov, A.T.

1987-01-01

Application of the principle of gauging to linear canonical symmetries of simplest/rudimentary/bilinear lagrangians is shown to produce a relativistic version of the Lagrangian describing N particles bound by harmonic forces. For pairwise coupled identical particles the gauge group is T 1 xU 1 , xSU N-1 . A model for the relativistic discrete string (a chain of N particles) is also discussed. All these gauge theoried of particles can be quantized by standard methods

Geometrical and topological formulation of local gauge and supergauge theories

International Nuclear Information System (INIS)

Macrae, K.I.

1976-01-01

A geometrical and topological formulation of local gauge and supergauge invariance is presented. Analysis of experiments of the type described by Bohm and Aharanov and in the attempt to understand immersed submanifolds such as the string with internal symmetry, in a geometric setting, are led to the introduction of fiber bundles, superspaces. Many exact classical solutions to the equations of motion were considered for these gauge theories with specific choices of gauge group such as SU 4 . We describe some exact soliton solutions to these theories which have linear Regge trajectories, i.e., their angular momentum is a linear function of their mass squared. Next one discusses the actions and equations of motion for gauge theories whose base manifolds can have arbitrarily dimensioned submanifolds excised from them, manifolds with holes were discussed. These holes can have fractional quark charges when the structure group is, for example, SU 3 or SU 4 . By extending the concept of conservation of energy to include the excised submanifolds, their actions, and their equations of motion were derived showing that they can act as charged particles. Using the fractionality of the quark charges, are led to suggest a topological confinement mechanism for these particles. One also derives the actions and equations of motion for the string from this viewpoint. Some new Lie algebras which have anticommuting elements are introduced. Their gauge theories are described, and the possibility of fermionic actions for the anticommuting pieces is examined. Supersymmetric strings and their supergauge transformations were discussed and an extension was suggested of supersymmetry to immersed minimal submanifolds other than the string. Both quarklike and vectorlike fermions are included. Finally the invariance of both the equations of motion and the gauge conditions under supersymmetry transformations for these submanifolds were described

Moduli space of self-dual connections in dimension greater than four for abelian Gauge groups

OpenAIRE

Cappelle, Natacha

2018-01-01

In 1954, C. Yang and R. Mills created a Gauge Theory for strong interaction of Elementary Particles. More generally, they proved that it is possible to define a Gauge Theory with an arbitrary compact Lie group as Gauge group. Within this context, it is interesting to find critical values of a functional defined on the space of connections: the Yang-Mills functional. If the based manifold is four dimensional, there exists a natural notion of (anti-)self-dual 2-form, which gives a natural notio...

Study of Λ parameters and crossover phenomena in SU(N) x SU(N) sigma models in two dimensions

International Nuclear Information System (INIS)

Shigemitsu, J.; Kogut, J.B.

1981-01-01

The spin system analogues of recent studies of the string tension and Λ parameters of SU(N) gauge theories in 4 dimensions are carried out for the SU(N) x SU(N) and O(N) models in 2 dimensions. The relations between the Λ parameters of both the Euclidean and Hamiltonian formulation of the lattice models and the Λ parameter of the continuum models are obtained. The one loop finite renormalization of the speed of light in the lattice Hamiltonian formulations of the O(N) and SU(N) x SU(N) models is calculated. Strong coupling calculations of the mass gaps of these spin models are done for all N and the constants of proportionality between the gap and the Λ parameter of the continuum models are obtained. These results are contrasted with similar calculations for the SU(N) gauge models in 3+1 dimensions. Identifying suitable coupling constants for discussing the N → infinity limits, the numerical results suggest that the crossover from weak to strong coupling in the lattice O(N) models becomes less abrupt as N increases while the crossover for the SU(N) x SU(N) models becomes more abrupt. The crossover in SU(N) gauge theories also becomes more abrupt with increasing N, however, at an even greater rate than in the SU(N) x SU(N) spin models

Gauge theory of the post-Galilean groups

International Nuclear Information System (INIS)

Dimakis, A.

1985-01-01

By means of an extension of the field of real numbers we construct post-Galilean groups, which in a sense lay between the Galilean group and the Lorentz group. By gauging these groups we obtain a frame theory of gravitation, which comprises Newton--Cartan theory, general relativity, and an infinite number of intermediate theories. This leads to a better understanding of how the structural differences of the two main theories of gravitation arise

Magnetic polarizabilities of light mesons in SU(3 lattice gauge theory

Directory of Open Access Journals (Sweden)

E.V. Luschevskaya

2015-09-01

Full Text Available We investigate the ground state energies of neutral pseudoscalar and vector meson in SU(3 lattice gauge theory in the strong abelian magnetic field. The energy of ρ0 meson with zero spin projection sz=0 on the axis of the external magnetic field decreases, while the energies with non-zero spins sz=−1 and +1 increase with the field. The energy of π0 meson decreases as a function of the magnetic field. We calculate the magnetic polarizabilities of pseudoscalar and vector mesons for lattice volume 184. For ρ0 with spin |sz|=1 and π0 meson the polarizabilities in the continuum limit have been evaluated. We do not observe any evidence in favour of tachyonic mode existence.

Spontaneous symmetry breaking and fermion chirality in higher-dimensional gauge theory

International Nuclear Information System (INIS)

Wetterich, C.

1985-01-01

The number of chiral fermions may change in the course of spontaneous symmetry breaking. We discuss solutions of a six-dimensional Einstein-Yang-Mills theory based on SO(12). In the resulting effective four-dimensional theory they can be interpreted as spontaneous breaking of a gauge group SO(10) to H=SU(3)sub(C)xSU(2)sub(L)xU(1)sub(R)xU(1)sub(B-L). For all solutions, the fermions which are chiral with respect to H form standard generations. However, the number of generations for the solutions with broken SO(10) may be different compared to the symmetric solutions. All solutions considered here exhibit a local generation group SU(2)sub(G)xU(1)sub(G). For the solutions with broken SO(10) symmetry, the leptons and quarks within one generation transform differently with respect to SU(2)sub(G)xU(1)sub(G). Spontaneous symmetry breaking also modifies the SO(10) relations among Yukawa couplings. All this has important consequences for possible fermion mass relations obtained from higher-dimensional theories. (orig.)

Gauge coupling running in minimal SU(3) x SU(2) x U(1) superstring unification

CERN Document Server

Ibáñez, L E; Ross, Graham G

1991-01-01

We study the evolution of the gauge coupling constants in string unification schemes in which the light spectrum below the compactification scale is exactly that of the minimal supersymmetric standard model. In the absence of string threshold corrections the predicted values $\\sin^2\\theta _W=0.218$ and $\\alpha _s=0.20$ are in gross conflict with experiment, but these corrections are generically important. One can express the string threshold corrections to $\\sin^2\\theta _W$ and $\\alpha_s$ in terms of certain $modular$ $weights$ of quark, lepton and Higgs superfields as well as the $moduli$ of the string model. We find that in order to get agreement with the experimental measurements within the context of this $minimal$ scheme, certain constraints on the $modular$ $weights$ of the quark, lepton and Higgs superfields should be obeyed. Our analysis indicates that this $minimal$ $string$ $unification$

Nonperturbative flipped SU(5) vacua in heterotic M-theory

Energy Technology Data Exchange (ETDEWEB)

Faraggi, Alon E. E-mail: faraggi@thphys.ox.ac.uk; Garavuso, Richard E-mail: garavuso@thphys.ox.ac.uk; Isidro, Jose M. E-mail: isidro@thphys.ox.ac.uk

2002-10-07

The evidence for neutrino masses in atmospheric and solar neutrino experiments provides further support for the embedding of the Standard Model fermions in the chiral 16 SO(10) representation. Such an embedding is afforded by the realistic free fermionic heterotic-string models. In this paper we advance the study of these string models toward a nonperturbative analysis by generalizing the work of Donagi, Pantev, Ovrut and Waldram from the case of G=SU(2n+1) to G=SU(2n) stable holomorphic vector bundles on elliptically fibered Calabi-Yau manifolds with fundamental group Z{sub 2}. We demonstrate existence of G=SU(4) solutions with three generations and SO(10) observable gauge group over Hirzebruch base surface, whereas we show that certain classes of del Pezzo base surface do not admit such solutions. The SO(10) symmetry is broken to SU(5)xU(1) by a Wilson line. The overlap with the realistic free fermionic heterotic-string models is discussed.

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

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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.