Integrating out Holographic QCD back to Hidden Local Symmetry

We develop a previously proposed gauge-invariant method to integrate out infinite towers of vector and axialvector mesons arising as Kaluza-Klein (KK) modes in a class of holographic models of QCD (HQCD). We demonstrate that HQCD can be reduced to the chiral perturbation theory (ChPT) with the hidden local symmetry (HLS) (so-called HLS-ChPT) having only the lowest KK mode identified as the HLS gauge boson, and the Nambu-Goldstone bosons. The ${\cal O} (p^4)$ terms in the HLS-ChPT are completely determined by integrating out infinite towers of vector/axialvector mesons in HQCD: Effects of higher KK modes are fully included in the coefficients. As an example, we apply our method to the Sakai-Sugimoto model.Comment: To appear in proceedings of SCGT09, Nagoya, Japan, 8 page

Holographic Techni-dilaton

Techni-dilaton, a pseudo-Nambu-Goldstone boson of scale symmetry, was predicted long ago in the Scale-invariant/Walking/Conformal Technicolor (SWC-TC) as a remnant of the (approximate) scale symmetry associated with the conformal fixed point, based on the conformal gauge dynamics of ladder Schwinger-Dyson (SD) equation with non-running coupling. We study the techni-dilaton as a flavor-singlet bound state of techni-fermions by including the techni-gluon condensate (tGC) effect into the previous (bottom-up) holographic approach to the SWC-TC, a deformation of the holographic QCD with $\gamma_m \simeq 0$ by large anomalous dimension $\gamma_m \simeq 1$. With including a bulk scalar field corresponding to the gluon condensate, we first improve the Operator Product Expansion of the current correlators so as to reproduce gluonic $1/Q^4$ term both in QCD and SWC-TC. We find in QCD about $10\%$ (negative) contribution of gluon condensate to the $\rho$ meson mass. We also calculate the oblique electroweak $S$-parameter in the presence of the effect of the tGC and find that for the fixed value of $S$ the tGC effects dramatically reduce the flavor-singlet scalar (techni-dilaton) mass $M_{\rm TD}$ (in the unit of $F_\pi$), while the vector and axial-vector masses $M_\rho$ and $M_{a_1}$ are rather insensitive to the tGC, where $F_\pi$ is the decay constant of the techni-pion. If we use the range of values of tGC implied by the ladder SD analysis of the non-perturbative scale anomaly in the large $N_f$ QCD near the conformal window, the phenomenological constraint $S \simeq 0.1$ predicts the techni-dilaton mass $M_{\rm TD} \sim 600$ GeV which is within reach of LHC discovery.Comment: 28 pages, 11 eps files, typos corrected, references added, Fig.1 corrected, some discussions added, to be published in PR

Holographic QCD Integrated back to Hidden Local Symmetry

We develop a previously proposed gauge-invariant method to integrate out infinite tower of Kaluza-Klein (KK) modes of vector and axialvector mesons in a class of models of holographic QCD (HQCD). The HQCD is reduced by our method to the chiral perturbation theory with the hidden local symmetry (HLS) having only the lowest KK mode identified as the HLS gauge boson. We take the Sakai-Sugimoto model as a concrete HQCD, and completely determine the ${\cal O} (p^4)$ terms as well as the ${\cal O}(p^2)$ terms from the DBI part and the anomaly-related (intrinsic parity odd) gauge-invariant terms from the CS part. Effects of higher KK modes are fully included in these terms. To demonstrate power of our method, we compute momentum-dependences of several form factors such as the pion electromagnetic form factors, the $\pi^0$-$\gamma$ and $\omega$-$\pi^0$ transition form factors compared with experiment, which was not achieved before due to complication to handle infinite sums. We also study other anomaly-related quantities like $\gamma^*$-$\pi^0$-$\pi^+$-$\pi^-$ and $\omega$-$\pi^0$-$\pi^+$-$\pi^-$ vertex functions.Comment: 4 eps figures, 37 pages, latex, typos fixed; some discussions and references added; fig.4 replace

Desynchronization of pathological low-frequency brain activity by the hypnotic drug zolpidem.

Reports of the beneficial effects of the hypnotic imidazopyridine, zolpidem, described in persistent vegetative state^1, 2^ have been replicated recently in brain-injured and cognitively impaired patients^3-7^. Previous single photon emission computed tomography (SPECT) studies have suggested that sub-sedative doses of zolpidem increased regional cerebral perfusion in affected areas^5, 8^, implying enhanced neuronal metabolic activity; which has led to speculation that zolpidem 'reawakens' functionally dormant cortex. However, a neuronal mechanism by which this hypnotic drug affords benefits to brain injured patients has yet to be demonstrated. Here, we report the action of sub-sedative doses of zolpidem on neuronal network oscillatory activity in human brain, measured using pharmaco-magnetoencephalography (pharmaco-MEG). Study participant JP suffered a stroke in 1996, causing major damage to the left hemisphere that impaired aspects of both motor and cognitive function. Pharmaco-MEG analyses revealed robust and persistent pathological theta (4-10Hz) and beta (15-30Hz) oscillations within the lesion penumbra and surrounding cortex. Administration of zolpidem (5mg) reduced the power of pathological theta and beta oscillations in all regions of the lesioned hemisphere. This desynchronizing effect correlated well with zolpidem uptake (occurring approximately 40 minutes after acute administration) and was coincident with marked improvements in cognitive and motor function. Control experiments revealed no effect of placebo, while a structurally unrelated hypnotic, zopiclone, administered at a comparable dose (3.5mg) elicited widespread increases in cortical oscillatory power in the beta (15-30Hz) band without functional improvement. These results suggest that in JP, specific motor and cognitive impairments are related to increased low-frequency oscillatory neuronal network activity. Zolpidem is unique amongst hypnotic drugs in its ability to desynchronize such pathological low-frequency activity, thereby restoring cognitive function

Gap Equations and Electroweak Symmetry Breaking

Recently a new dynamical symmetry breaking model of electroweak interactions was proposed based on interacting fermions. Two fermions of different SU(2) representations form a symmetry breaking condensate and generate the lepton and quark masses. The weak gauge bosons get their usual standard model masses from a gauge invariant Lagrangian of a composite doublet scalar field. The new fermion fields become massive by condensation. In this note the gap equations are given in the linearized (mean field) approximation and the conditions for symmetry breaking and mass generation are presented. Perturbative unitarity constrains the self-couplings and the masses of the new fermions, a raw spectrum is given.Comment: 10 pages, 4 figure

Constraints and Hamiltonian in Light-Front Quantized Field Theory

Self-consistent Hamiltonian formulation of scalar theory on the null plane is constructed following Dirac method. The theory contains also {\it constraint equations}. They would give, if solved, to a nonlinear and nonlocal Hamiltonian. The constraints lead us in the continuum to a different description of spontaneous symmetry breaking since, the symmetry generators now annihilate the vacuum. In two examples where the procedure lacks self-consistency, the corresponding theories are known ill-defined from equal-time quantization. This lends support to the method adopted where both the background field and the fluctuation above it are treated as dynamical variables on the null plane. We let the self-consistency of the Dirac procedure determine their properties in the quantized theory. The results following from the continuum and the discretized formulations in the infinite volume limit do agree.Comment: 11 pages, Padova University preprint DFPF/92/TH/52 (December '92