15957415
The topological structure of the space–time disclination
The space–time disclination is studied by making use of the decomposition theory of gauge potential in terms of the antisymmetric tensor field and φ-mapping method. It is shown that the self-dual and anti-self-dual parts of the curvature compose the space–time disclinations which are classified in terms of topological invariants—winding number. The projection of space–time disclination density along an antisymmetric tensor field is quantized topologically and characterized by Brouwer degree and Hopf index.
18661974
Decomposition Theory of Spin Connection and Topological Structure of Gauss-Bonnet-Chern Theorem on Manifold With Boundary
The index theorem of Euler-Poincar\'e characteristic of manifold with boundary is given by making use of the general decomposition theory of spin connection. We shows the sum of the total index of a vector field $\phi $ and half the total of the projective vector field of $\phi $ on the boundary equals the Euler-Poincar\'e characteristic of the manifold. Detailed discussion on the topological structure of the Gauss-Bonnet-Chern theorem on manifold with boundary is given. The Hopf indices and Brouwer degrees label the local structure of the Euler density.
14097607
The topological structure of Nieh-Yan form and the chiral anomaly in spaces with torsion
The topological structure of the Nieh-Yan form in a four-dimensional manifold is given by making use of the decomposition of spin connection. The case of the generalized Nieh-Yan form on a 2d-dimensional manifold is discussed with an example of an eight-dimensional case which is studied in detail. The chiral anomaly with nonvanishing torsion is also studied. The further contributions from the torsional part to the chiral anomaly are found to estimate from the zeros of some fields under the pure gauge condition.
120598852
DECOMPOSITION OF SU(N) CONNECTION AND MASS GAP IN ITS EFFECTIVE THEORY
189809274
Dirac structure of quark-hadron vertex in Bethe-Salpeter wave function under the framework covariant instantaneous ansatz
In the framework of covariant instantaneous ansatz, the general form of the quark-hadron vertex of certain kind of mesons is provided; how to arrange the Dirac covariants of the complete set by the power counting rule is discussed. Employing the leading order Dirac covariants for vector and pseudoscalar mesons, their decay constants are calculated. This proceeding paper is complementary to our other two previous papers, emphasizing on some conceptual discussions. The strong interaction is special for its basic degree of freedoms are confined in hadrons, preventing the measurement of the “really-free” quanta, i.e., quarks and gluons in quantum chromodynamics (QCD). Hence, a description for the asymptotic states, the hadrons, in the strong interactions/collisions, with the language of the basic quanta/fields, quarks, and gluons, is a necessary but challenging task. In the framework of relativistic quantum field theory, at least one “standard” way to describe bound states, i.e., the Bethe-Salpeter wave function (BSW), which is the solution of the Bethe-Salpeter integral equation (BSE), seems available. Through an extensive employment of various techniques in the quantum field theory, such as the DysonSchwinger Equations, one may expect to know the movement of the quarks and gluons in hadrons, and to calculate various kinds of interactions/collisions in various energy scales with such knowledge. This is one of the most important purposes of studying the hadron structure. However, a full understanding of the physical picture of the BSW and a satisfactory way to solve the BES in QCD are still beyond approach. Even, one is not able to give the “rigorous” form of the kernel of the BSE without practical non-perturbative techniques in QCD. More specifically, one has a very powerful picture/tool in high energy hadronic interactions, i.e., the perturbative QCD inspired parton model, but how to approach this parton picture starting from low energy BSW of hadron is an open question. At the same time, the standard factorization scheme is often facing danger in various special processes [1, 2]. So it is very much justified to put more labour on the study of BSW/BSE, especially their
119182320
Colour connections of four quark $Q\bar{Q}Q'\bar{Q}'$ system and doubly heavy baryon production in $e^{+}e^{-}$ annihilation
The hadronization effects induced by various colour connections of the four quark system in $e^{+}e^{-}$ annihilation are briefly reviewed. A special colour connection of four heavy quark system without colour-separation favours the production of doubly heavy baryons. For the related three-jet case, the corresponding hadronization has not been considered. We argue that it can be effectively described as two string fragmentation besides the leading heavy diquark fragmentation. The production rate and the properties of final state hadron systems are discussed. Emphasis is on the string effect as a finger print of this hadronization procedure.
119280900
Observational constraints on K-inflation models
We extend the ModeCode software of Mortonson, Peiris and Easther [1] to enable numerical computation of perturbations in K-inflation models, where the scalar field no longer has a canonical kinetic term. Focussing on models where the kinetic and potential terms can be separated into a sum, we compute slow-roll predictions for various models and use these to verify the numerical code. A Markov chain Monte Carlo analysis is then used to impose constraints from WMAP7 data on the addition of a term quadratic in the kinetic energy to the Lagrangian of simple chaotic inflation models. For a quadratic potential, the data do not discriminate against addition of such a term, while for a quartic (λ4) potential inclusion of such a term is actually favoured. Overall, constraints on such a term from present data are found to be extremely weak.
46336718
Propagation of field disturbances in Yang-Mills theory
The propagation of field disturbances is examined in the context of the effective Yang-Mills Lagrangian, which is intended to be applied to QCD systems. It is shown that birefringence phenomena can occur in such systems provided some restrictive conditions, as causality, are fulfilled. Possible applications to phenomenology are addressed.
115465221
OPERA Collaboration have observed phase speed of neutrino wave function, while advanced time displacement is mainly due to finite life time of pion
First we call the attention that velocity defined by ratio between some intervals of space and time respectively is sometimes ambiguous, in the framework of quantum theory. Velocity in general is not possible to be well defined as some generator of certain space-time symmetry operation. Then in section 3 by analyzing the OPERA experiment we show that the OPERA Collaboration may have measured the phase speed of the neutrino wave function. Employing a very (maybe too) simple model which is just a reproduction from Brillouin's classical book, we demonstrate the phase velocity and group velocity. These are just a qualitative illustration rather than aiming to quantitively explain the OPERA data. However, how to rigorously define the phase containing the particle production ordering information as a space-time distribution observable in QFT needs more investigations. Due to the finite life time of the pions (w.r.t. its flying time in the 1 km long tunnel) which decay to the muon neutrinos, the wave form for neutrinos recorded by OPERA is deformed from that of the proton. Such an effect is estimated to lead to an advanced time displacement of the order of 100ns, which coincides with the measured. Such an effect can only be significant when measuring phase speed and the recorded neutrino events per extraction of proton smaller than one, as the OPERA case.