共查询到20条相似文献,搜索用时 812 毫秒
1.
《Nuclear Physics B》1988,302(1):65-80
We examine the low-energy limits of the one-particle irreducible one-loop amplitudes in the heterotic superstring for five gravitons, for three gravitons and two gauge bosons, and for one graviton and four gauge bosons. In agreement with general arguments, explicit calculation shows that there is a Wess-Zumino term in the low-energy effective action for D = 10 supergravity. 相似文献
2.
E. Koorambas 《International Journal of Theoretical Physics》2013,52(7):2235-2244
We propose an alternative understanding of gravity, resulting from the extension of N. Wu’s gauge theory of gravity with massive gravitons, which are minimally coupled to massless gravitons. Based on this, we derive the equations of state for massive gravitons. We study the dynamics of these massive gravitons in a flat, homogeneous and isotropic Friedmann-Robertson-Walker (FRW) universe. We calculate the critical points of the massive graviton dark energy interacting with background perfect fluid. These calculations may have crucial implications for the massive gravitons and dark energy theories. They could, therefore, have important repercussions for current cosmological problems. 相似文献
3.
Gauge theory of gravity is formulated based on principle of local gauge invariance. Because the model hasstrict local gravitational gauge symmetry, and gauge theory of gravity is a perturbatively renormalizable quantum model.However, in the original model, all gauge gravitons are massless. We want to ask whether there exist massive gravitonsin Nature. In this paper, we will propose a gauge model with massive gravitons. The mass term of gravitational gaugefield is introduced into the theory without violating the strict local gravitational gauge symmetry. Massive gravitons canbe considered to be possible origin of dark energy and dark matter in the Universe. 相似文献
4.
A review of some recent papers on gauge theories of weak and strong gravity is presented. For weak gravity, SL(2, C) gauge
theory along with tetrad formulation is described which yields massless spin-2 gauge fields (quanta gravitons). Next a unified
SL(2n,C) model is discussed along with Higgs fields. Its internal symmetry is SU(n). The free field solutions after symmetry breaking yield massless spin-1 (photons) and spin-2 (gravitons) gauge fields and
also massive spin-1 and spin-2 bosons. The massive spin-2 gauge fields are responsible for short range superstrong gravity.
Higgs-fermion interaction can lead to baryon and lepton number non-conservation. The relationship of strong gravity with other
forces is also briefly considered. 相似文献
5.
K. Hagiwara J. Kanzaki Q. Li K. Mawatari 《The European Physical Journal C - Particles and Fields》2008,56(3):435-447
Fortran subroutines to calculate helicity amplitudes with massive spin-2 particles (massive gravitons), which couple to the
standard model particles via the energy momentum tensor, are added to the HELAS (HELicity Amplitude Subroutines) library. They are coded in such a way that arbitrary scattering amplitudes with one graviton production and its
decays can be generated automatically by MadGraph and MadEvent, after slight modifications. All the codes have been tested carefully by making use of the invariance of the helicity amplitudes
under the gauge and general coordinate transformations. 相似文献
6.
Motivated by the problem of expanding the single-trace tree-level amplitude of Einstein-Yang-Mills theory to the BCJ basis of Yang-Mills amplitudes, we present an alternative expansion formula in gauge invariant vector space. Starting from a generic vector space consisting of polynomials of momenta and polarization vectors, we define a new sub-space as a gauge invariant vector space by imposing constraints on the gauge invariant conditions. To characterize this sub-space, we compute its dimension and construct an explicit gauge invariant basis from it. We propose an expansion formula in this gauge invariant basis with expansion coefficients being linear combinations of the Yang-Mills amplitude, manifesting the gauge invariance of both the expansion basis and coefficients. With the help of quivers, we compute the expansion coefficients via differential operators and demonstrate the general expansion algorithm using several examples. 相似文献
7.
《Nuclear Physics B》1996,467(3):479-509
We show, for previously uncalculated examples containing a uniform mass in the loop, that it is possible to obtain complete massive one-loop gauge theory amplitudes solely from unitarity and known ultraviolet or infrared mass singularities. In particular, we calculate four-gluon scattering via massive quark loops in QCD. The contribution of a heavy quark to five-gluon scattering with identical helicities is also presented. 相似文献
8.
E.Koorambas 《理论物理通讯》2012,57(2):241-244
We test the Wu gauge theory of gravity with massive gravitons in the perturbing topological field theory framework.We show that the computation of the correlation function between massive and massless gravitons is reported up to 4-loop and appears to be unaffected by radiative correction.This result ensures the stability of the linking number between massive and massless gravitons with respect to the local perturbation,a result with potential wider applications in cosmology. 相似文献
9.
E. Tomboulis 《Physics letters. [Part B]》1977,67(4):417-420
Using an essentially dispersive approach to renormalization that allows us to consider subdivergences on-shell, we show that in supergravitational 2-loop amplitudes with external gravitons all non-local, non-renormalizable divergences cancel on-shell. 相似文献
10.
V. V. Skobelev 《Russian Physics Journal》1975,18(1):62-65
Amplitudes of photon-graviton scattering and the crossing process (annihilation of two photons into two gravitons and the reverse) are calculated. It is shown that the amplitudes are gradient invariant. It is also determined that upon scattering at any angle the spirality of photons and ravitons remains unchanged, and annihilation is possible only with identical spirality of photons (gravitons). The dependence of differential section on scattering angle is analyzed. 相似文献
11.
Dr. U. Bleyer 《Annalen der Physik》1982,494(3):209-215
We consider some properties of TREDER'S tetrad theories, derived in I, using the field equations proposed by KASPER and LIEBSCHER . The linearized theory is considered, because the field energy becomes positive, if the energy of the weak field is a positive one. Using the dynamical equations, the field equations lead for the symmetric part of the field to the gauge invariant field equations in Hilbert gauge and to corresponding equations for the antisymmetric part. This means that in this approximation the dynamical equations replace the gauge invariance and the tetrad field corresponds to a mixture of tensor and scalar gravitons. We discuss possible experiments for showing the existence of scalar gravitons and limiting the free parameter of the theory. 相似文献
12.
Leonardo Modesto 《General Relativity and Gravitation》2005,37(1):207-213
In this paper we work in perturbative quantum gravity coupled to scalar matter at tree level and we introduce a new effective model in analogy with the Fermi theory of weak interaction and in relation with a previous work where we have studied only the gravity and its self-interaction. This is an extension of the I.T.B. model (Intermediate-Tensor-Boson) for gravity also to gravitationally interacting scalar matter. We show that in a particular gauge the infinite series of interactions containing n gravitons and two scalars could be rewritten in terms of only two Lagrangians containing a massive field, the graviton and, obviously, the scalar field. Using the S-matrix we obtain that the low energy limit of the amplitude reproduces the local Lagrangian for the scalar coupled to gravity. 相似文献
13.
We investigate single bremsstxahlung processes in gauge theories involving massless scalars and fermions interacting with photons and gravitons.As in QED and SU(N),we find that the cross sections are very simple and can be factorized in two parts:a generalized infrared factor and a factor which is related to the lowest order elastic process. 相似文献
14.
《中国科学:物理学 力学 天文学(英文版)》2020,(7)
Form factors are quantities that involve both asymptotic on-shell states and gauge invariant operators. They provide a natural bridge between on-shell amplitudes and off-shell correlation functions of operators, thus allowing us to use modern on-shell amplitude techniques to probe into the off-shell side of quantum field theory. In particular, form factors have been successfully used in computing the cusp(soft) anomalous dimensions and anomalous dimensions of general local operators. This review is intended to provide a pedagogical introduction to some of these developments. We will first review some amplitudes background using four-point amplitudes as main examples. Then we generalize these techniques to form factors, including(1) tree-level form factors,(2) Sudakov form factor and infrared singularities, and(3) form factors of general operators and their anomalous dimensions. Although most examples we consider are inN= 4 super-Yang-Mill theory, the on-shell methods are universal and are expected to be applicable to general gauge theories. 相似文献
15.
Scattering amplitudes of gluons coupled with a pair of massive scalars, so-called massive scalar amplitudes, provide the simplest yet physically useful examples of massive amplitudes. In this paper we construct an S-matrix functional for the massive scalar amplitudes in a recently developed holonomy formalism in supertwistor space. From the S-matrix functional we derive ultra helicity violating (UHV), as well as next-to-UHV (NUHV), massive scalar amplitudes at tree level in a form that agrees with previously known results. We also obtain recursive expressions for non-UHV tree amplitudes in general. These results will open up a new avenue to the study of phenomenology in the spinor-helicity formalism. 相似文献
16.
We review some properties of solutions to 5D Einstein gravity with a discrete fifth dimension. Those properties depend on the discretization scheme we use. In particular, we find that the neglect of the lapse field (along the discretized direction) gives rise to Randall–Sundrum-type metric with a negative tension brane. However, no brane source is required. The inclusion of the lapse field gives rise to solutions whose continuum limit is gauge fixed by the discretization scheme. We show also that the models allow a continuous mass spectrum for the gravitons with an effective 4D interaction at small scales. 相似文献
17.
Krzysztof Gawȩdzki Rafał R. Suszek Konrad Waldorf 《Communications in Mathematical Physics》2011,302(2):513-580
We revisit the gauging of rigid symmetries in two-dimensional bosonic sigma models with a Wess-Zumino term in the action.
Such a term is related to a background closed 3-form H on the target space. More exactly, the sigma-model Feynman amplitudes of classical fields are associated to a bundle gerbe with connection of curvature H over the target space. Under conditions that were unraveled more than twenty years ago, the classical amplitudes may be coupled
to the topologically trivial gauge fields of the symmetry group in a way which assures infinitesimal gauge invariance. We
show that the resulting gauged Wess-Zumino amplitudes may, nevertheless, exhibit global gauge anomalies that we fully classify.
The general results are illustrated on the example of the WZW and the coset models of conformal field theory. The latter are
shown to be inconsistent in the presence of global anomalies. We introduce a notion of equivariant gerbes that allow an anomaly-free coupling of the Wess-Zumino amplitudes to all gauge fields, including the ones in non-trivial
principal bundles. Obstructions to the existence of equivariant gerbes and their classification are discussed. The choice
of different equivariant structures on the same bundle gerbe gives rise to a new type of discrete-torsion ambiguities in the
gauged amplitudes. An explicit construction of gerbes equivariant with respect to the adjoint symmetries over compact simply
connected simple Lie groups is given. 相似文献
18.
The interaction between gravitons and fermions is investigated in the teleparallel gravity. The scattering of fermions and gravitons in the weak field approximation is analyzed. The transition amplitudes of M\(\varnothing \)ller, Compton and new gravitational scattering are calculated. 相似文献
19.
We derive the analog of the Cachazo–Svr?ek–Witten (CSW) diagrammatic Feynman rules for four-dimensional Yang–Mills gauge theory coupled to a massive colored scalar. The mass term is shown to give rise to a new tower of vertices in addition to the CSW vertices for massless scalars in non-supersymmetric theories. The rules are derived directly from an action, once through a canonical transformation within light-cone Yang–Mills and once by the construction of a twistor action. The rules are tested against known results in several examples and are used to simplify the proof of on-shell recursion relations for amplitudes with massive scalars. 相似文献
20.
We propose an optical lattice scheme which would permit the experimental observation of Zitterbewegung (ZB) with ultracold, neutral atoms. A four-level tripod variant of the setup for stimulated Raman adiabatic passage (STIRAP) has previously been proposed for generating non-Abelian gauge fields. Dirac-like Hamiltonians, which exhibit ZB, are simple examples of such non-Abelian gauge fields; we show how a variety of them can arise, and how ZB can be observed, in a tripod system. We predict that the ZB should occur at experimentally accessible frequencies and amplitudes. 相似文献