共查询到20条相似文献,搜索用时 15 毫秒
1.
Anna Kamińska Stéphane Lavignac 《The European Physical Journal C - Particles and Fields》2011,71(12):1811
We study the interplay between the spontaneous breaking of a global symmetry of the Higgs sector and gauge-mediated supersymmetry
breaking, in the framework of a supersymmetric model with global SU(3) symmetry. In addition to solving the supersymmetric flavor problem and alleviating the little hierarchy problem, this
scenario automatically triggers the breaking of the global symmetry and provides an elegant solution to the μ/Bμ problem of gauge mediation. We study in detail the processes of global symmetry and electroweak symmetry breaking, including
the contributions of the top/stop and gauge-Higgs sectors to the one-loop effective potential of the pseudo-Goldstone Higgs
boson. While the joint effect of supersymmetry and of the global symmetry allows in principle the electroweak symmetry to
be broken with little fine-tuning, the simplest version of the model fails to bring the Higgs mass above the LEP bound due
to a suppressed tree-level quartic coupling. To cure this problem, we consider the possibility of additional SU(3)-breaking contributions to the Higgs potential, which results in a moderate fine-tuning. The model predicts a rather low
messenger scale, a small tanβ value, a light Higgs boson with Standard Model-like properties, and heavy higgsinos. 相似文献
2.
Zhen-Hua Zhang Ya-Dong Yang Xin-Heng Guo Gang Lü Anton Wiranata 《The European Physical Journal C - Particles and Fields》2013,73(9):1-7
In the Standard Model, the Higgs potential allows only one minimum at tree level. But the open possibility that there might be two scalar doublets enriches the vacuum structure, allowing for the risk that we might now be in a metastable state, which we dub the panic vacuum. Current experiments at the LHC are probing the Higgs particle predicted as a result of the spontaneous symmetry breaking. Remarkably, in the two Higgs model with a softly broken U(1) symmetry, the LHC experiments already allow to exclude many panic vacuum solutions. 相似文献
3.
The Higgs sector of the MSSM may be extended to solve the μ problem by the addition of a gauge singlet scalar field. We consider an extended Higgs model. For simplicity we consider
the case where all the fields in the scalar sector are real.
We analyze the vacuum structure of the model. We address the question of an exothermic phase transition from a broken susy
phase with electroweak symmetry breaking (our current universe) to an exact susy phase with electroweak symmetry breaking
(future susy universe). 相似文献
4.
We characterize models where electroweak symmetry breaking is driven by two light Higgs doublets arising as pseudo-Nambu-Goldstone bosons of new dynamics above the weak scale. They represent the simplest natural two Higgs doublet alternative to supersymmetry. We construct their low-energy effective Lagrangian making only few specific assumptions about the strong sector. These concern their global symmetries, their patterns of spontaneous breaking and the sources of explicit breaking. In particular we assume that all the explicit breaking is associated with the couplings of the strong sector to the Standard Model fields, that is gauge and (proto)-Yukawa interactions. Under those assumptions the scalar potential is determined at lowest order by very few free parameters associated to the top sector. Another crucial property of our scenarios is the presence of a discrete symmetry, in addition to custodial SO(4), that controls the T-parameter. That can either be simple CP or a Z2 that distinguishes the two Higgs doublets. Among various possibilities we study in detail models based on SO(6)/SO(4) × SO(2), focussing on their predictions for the structure of the scalar spectrum and the deviations of their couplings from those of a generic renormalizable two Higgs doublet model. 相似文献
5.
S. A. Selesnick 《International Journal of Theoretical Physics》2013,52(4):1088-1121
We consider symmetry breaking in the context of vector bundle theory, which arises quite naturally not only when attempting to “gauge” symmetry groups, but also as a means of localizing those global symmetry breaking effects known as spontaneous. We review such spontaneous symmetry breaking first for a simplified version of the Goldstone scenario for the case of global symmetries, and then in a localized form which is applied to a derivation of some of the phenomena associated with superconduction in both its forms, type I and type II. We then extend these procedures to effect the Higgs mechanism of electroweak theory, and finally we describe an extension to the flavor symmetries of the lightest quarks, including a brief discussion of CP-violation in the neutral kaon system. A largely self-contained primer of vector bundle theory is provided in Sect. 4, which supplies most of the results required thereafter. 相似文献
6.
7.
Dong-Won Jung 《Pramana》2007,69(5):789-793
In the extra dimensional scenarios with gauge fields in the bulk, the Kaluza-Klein (KK) gauge bosons can induce Nambu-Jona-Lasinio
(NJL) type attractive fourfermion interactions, which can break electroweak symmetry dynamically with accompanying composite
Higgs fields. We consider a possibility that electroweak symmetry breaking (EWSB) is triggered by both a fundamental Higgs
and a composite Higgs arising in a dynamical symmetry breaking mechanism induced by a new strong dynamics. The resulting Higgs
sector is a partially composite two-Higgs doublet model with specific boundary conditions on the coupling and mass parameters
originating at a compositeness scale Λ. The phenomenology of this model is discussed including the collider phenomenology
at LHC and ILC.
相似文献
8.
Recently Kim has given a general method, using group-invariant orbit parameters, for determining the energy and residual symmetry of the Higgs potential minimum. In this paper we illustrate the method by working out the case of a quartic SU(5) Higgs potential with and higgsons. In this method the Gell-Mann-Slansky conjecture concerning possible little groups of the potential minimum takes a geometric form, which is verified for our case. The results are used to discuss the hierarchical symmetry breaking of SU(5) grand unification theory. We generalize our results to the SU(N) adjoint + vector models, which are all closely related. 相似文献
9.
K. A. Bronnikov B. E. Meierovich E. R. Podolyak 《Journal of Experimental and Theoretical Physics》2002,95(3):392-403
We consider the gravitational properties of a global monopole on the basis of the simplest Higgs scalar triplet model in general relativity. We begin with establishing some common features of hedgehog-type solutions with a regular center, independent of the choice of the symmetry-breaking potential. There are six types of qualitative behaviors of the solutions; we show, in particular, that the metric can contain at most one simple horizon. For the standard Mexican hat potential, the previously known properties of the solutions are confirmed and some new results are obtained. Thus, we show analytically that solutions with the monotonically growing Higgs field and finite energy in the static region exist only in the interval 1 < λ < 3, where λ is the squared energy of spontaneous symmetry breaking in Planck units. The cosmological properties of these globally regular solutions apparently favor the idea that the standard Big Bang might be replaced with a nonsingular static core and a horizon appearing as a result of some symmetry-breaking phase transition at the Planck energy scale. In addition to the monotonic solutions, we present and analyze a sequence of families of new solutions with the oscillating Higgs field. These families are parametrized by n, the number of knots of the Higgs field, and exist for λ < γn=6/[(2n + 1)(n + 2)]; all such solutions possess a horizon and a singularity beyond it. 相似文献
10.
We refine the calculation of the SU(5) effective potential including Higgs and radiative contributions in the one-loop level. We give the mass spectrum and from this and the stability of the symmetry breaking pattern we derive bounds for the Higgs masses and inequalities between the Higgs couplings and the gauge coupling. 相似文献
11.
F. Ghaboussi 《International Journal of Theoretical Physics》1987,26(10):957-966
The connection between the minimality of the Higgs field potential and the maximal little groups of its representation obtained by spontaneous symmetry breaking is analyzed. It is shown that for several representations the lowest minimum of the potential is related to the maximal little group of those representations. Furthermore, a practical necessity criterion is given for the representation of the Higgs field needed for spontaneous symmetry breaking. 相似文献
12.
We consider a model where two new scalars are introduced in the standard model, assuming classical scale invariance. In this model the scale invariance is broken by quantum corrections and one of the new scalars acquires non-zero vacuum expectation value (VEV), which induces the electroweak symmetry breaking in the standard model, and the other scalar becomes dark matter. It is shown that TeV scale dark matter is realized, independent of the value of the other scalar?s VEV. The impact of the new scalars on the Higgs potential is also discussed. The Higgs potential is stabilized when the Higgs mass is over ∼120 GeV. 相似文献
13.
We study the spontaneous symmetry breaking in a conformally invariant gravitational theory. We particularly emphasize on the
nonminimal coupling of matter fields to gravity. By the nonminimal coupling we consider a local distinction between the conformal
frames of metric of matter fieldsand the metric explicitly entering the vacuum sector. We suppose that these two frames are
conformally related by a dilaton field. We show that the imposition of a condition on the variable mass term of a scalar field
may lead to the spontaneous symmetry breaking. In this way the scalar field may imitate the Higgs field behavior. Attributing
a constant configuration to the ground state of the Higgs field, a Higgs conformal frame is specified. We define the Higgs
conformal frame as a cosmological frame which describes the large scale characteristics of the observed universe. In the cosmological
frame the gravitational coupling acquires a correct value and one no longer deals with the vacuum energy problem. We then
study a more general case by considering a variable configuration for the ground state of Higgs field. In this case we introduce
a cosmological solution of themodel. 相似文献
14.
The structure of spontaneous breaking of SU(N) gauge symmetry for grand unification is investigated. The results obtained are applied to the analysis of SU(8) symmetry for which possible ways of breaking and intermediate symmetries are considered. It is assumed that the SU(8) group unifies the subgroups of colour, standard electroweak and horizontal symmetries. We find conditions which it is necessary to impose on the vacuum expectation values of Higgs multiplets to provide an arbitrary breaking pattern of SU(N) symmetry and conserve any intermediate symmetry. If in the SU(8) models considered fermions and mirror fermions do not violate the (V-A) and (V+A) structure of weak interactions, then their masses should not be greater than ~102 GeV. It is also shown that the contributions of fermion and Higgs multiplets to the renormalization group equation for the coupling constant of any subgroup of SU(N) are identical. Renormalization group identities for the case of arbitrary SU(N) breaking are given where the contribution of Higgs multiplets have been taken into account (but they cancel each other). Using these identities one can calculate the mass values for the breaking of the intermediate symmetries in the SU(8) models, and also exclude part of the possible breaking patterns. 相似文献
15.
Saul Barshay 《Zeitschrift fur Physik C Particles and Fields》1980,4(1):63-66
The various symmetry breaking patterns that are possible with a 24-plet and a 5-plet of Higgs fields in SU(5) are classified. Spontaneous breakdown of SU(5) to SU(3)colour×U(1) em can be achieved (excluding the gauge hierarchy problem) without imposing unnatural constraints on the parameters of the Higgs potential. 相似文献
16.
We consider the one-loop effective potential at zero and finite temperature in scalar field theories with anisotropic space-time scaling. For z=2, there is a symmetry breaking term induced at one loop at zero temperature and we find symmetry restoration through a first-order phase transition at high temperature. For z=3, we considered at first the case with a positive mass term at tree level and found no symmetry breaking effects induced at one loop, and then we study the case with a negative mass term at tree level where we cannot conclude about symmetry restoration effects at high temperature because of the imaginary parts that appear in the effective potential for small values of the scalar field. 相似文献
17.
We consider the effects of weak symmetry breaking by radiative corrections in a scheme of gauge hierarchies. We obtain new mass bounds on heavy fermions and show how discovery of a Higgs boson may distinguish between two different approaches to hierarchial spontaneous gauge symmetry breakdown. If there are no intrinsic mass scales below ~1015 GeV then discovery of a Higgs boson at ~9 GeV implies the existence of heavy fermions. 相似文献
18.
《Physics letters. [Part B]》1988,201(3):301-305
Higher dimensional gauge theories lead, after dimensional reduction on coset spaces, to four-dimensional gauge theories usually with the natural emergence of a Higgs sector which is completely determined. However, the Higgs fields never appear in the adjoint representation which in many GUTs could lead to a successful spontaneous symmetry breaking towards the low energy gauge group. As an alternative we suggest that the breaking of the four-dimensional GUTs obtained from CSDR could be provided by the Wilson flux breaking and we discuss some semirealistic examples. We also speculate on the possibility that the breaking of the electroweak sector has dynamical origin. 相似文献
19.
Damiano Anselmi 《The European Physical Journal C - Particles and Fields》2010,65(3-4):523-536
If Lorentz symmetry is violated at high energies, interactions that are usually non-renormalizable can become renormalizable by weighted power counting. Recently, a CPT invariant, Lorentz violating extension of the Standard Model containing two scalar-two fermion interactions (which can explain neutrino masses) and four fermion interactions (which can explain proton decay) was proposed. In this paper we consider a variant of this model, obtained suppressing the elementary scalar fields, and argue that it can reproduce the known low-energy physics. In the Nambu–Jona-Lasinio spirit, we show, using a large N c expansion, that a dynamical symmetry breaking takes place. The effective potential has a Lorentz invariant minimum and the Lorentz violation does not reverberate down to low energies. The mechanism generates fermion masses, gauge-boson masses and scalar bound states, to be identified with composite Higgs bosons. Our approach is not plagued by the ambiguities of approaches based on non-renormalizable vertices. The low-energy effective action is uniquely determined and predicts relations among parameters of the Standard Model. 相似文献
20.
F. Strocchi 《Communications in Mathematical Physics》1977,56(1):57-78
Spontaneous symmetry breakings in indefinite metric quantum field theories are analyzed and a generalization of the Goldstone theorem is proved. The case of local gauge quantum field theories is discussed in detail and a characterization is given of the occurrence of the Higgs mechanism versus the Goldstone mechanism. The Higgs phenomenon is explained on general grounds without the introduction of the so-called Higgs fields. The basic property is the relation between the local internal symmetry group and the local group of gauge transformations of the second kind. Spontaneous symmetry breaking ofc-number gauge transformations of the second kind is shown to always occur if there are charged local fields. The implications about the absence of mass gap in the Wightman functions and the occurrence of massless particles associated with the unbroken generators in the Higgs phenomenon are discussed. 相似文献