Anomalies, Chern-Simons Terms and Chiral Delocalization in Extra Dimensions

Gauge invariant topological interactions, such as the D=5 Chern-Simons terms, are required in models in extra dimensions that split anomaly free representations. The Chern-Simons term is necessary to maintain the overall anomaly cancellations of the theory, but it can have significant, observable, physical effects. The CS-term locks the KK-mode parity to the parity of space-time, leaving a single parity symmetry. It leads to new processes amongst KK-modes, eg, the decay of a KK-mode to a 2-body final state of KK-modes. A formalism for the effective interaction amongst KK-modes is constructed, and the decay of a KK-mode to KK-mode plus zero mode is analyzed as an example. We elaborate the general KK-mode current and anomaly structure of these theories. This includes a detailed study of the triangle diagrams and the associated ``consistent anomalies'' for Weyl spinors on the boundary branes. We also develop the non-abelian formalism. We illustrate this by showing in a simple way how a D=5 Yang-Mills ``quark flavor'' symmetry leads to the D=4 chiral lagrangian of mesons and the quantized Wess-Zumino-Witten term.Comment: 51 pages, 3 figures; Corrected typos, amplified discussio

Topological Physics of Little Higgs Bosons

Topological interactions will generally occur in composite Higgs or Little Higgs theories, extra-dimensional gauge theories in which A_5 plays the role of a Higgs boson, and amongst the pNGB's of technicolor. This phenomena arises from the chiral and anomaly structure of the underlying UV completion theory, and/or through chiral delocalization in higher dimensions. These effects are described by a full Wess-Zumino-Witten term involving gauge fields and pNGB's. We give a general discussion of these interactions, some of which may have novel signatures at future colliders, such as the LHC and ILC.Comment: 22 page

T-Parity Violation by Anomalies

Little Higgs theories often rely on an internal parity ("T-parity'') to suppress non-standard electroweak effects or to provide a dark matter candidate. We show that such a symmetry is generally broken by anomalies, as described by the Wess-Zumino-Witten term. We study a simple SU(3) x SU(3)/SU(3) Little Higgs scheme where we obtain a minimal form for the topological interactions of a single Higgs field. The results apply to more general models, including [SU(3) x SU(3)/SU(3)]^4, SU(5)/SO(5), and SU(6)/Sp(6).Comment: 17 page

Exact Equivalence of the D=4 Gauged Wess-Zumino-Witten Term and the D=5 Yang-Mills Chern-Simons Term

We derive the full Wess-Zumino-Witten term of a gauged chiral lagrangian in D=4 by starting from a pure Yang-Mills theory of gauged quark flavor in a flat, compactified D=5. The theory is compactified such that there exists a B_5 zero mode, and supplemented with quarks that are ``chirally delocalized'' with q_L (q_R) on the left (right) boundary (brane). The theory then necessarily contains a Chern-Simons term (anomaly flux) to cancel the fermionic anomalies on the boundaries. The constituent quark mass represents chiral symmetry breaking and is a bilocal operator in D=5 of the form: \bar{q}_LWq_R+h.c, where W is the Wilson line spanning the bulk, 0\leq x^5 \leq R and is interpreted as a chiral meson field, W=\exp(2i\tilde{\pi}/f_\pi), where f_\pi \sim 1/R. The quarks are integrated out, yielding a Dirac determinant which takes the form of a ``boundary term'' (anomaly flux return), and is equivalent to Bardeen's counterterm that connects consistent and covariant anomalies. The Wess-Zumino-Witten term then emerges straightforwardly, from the Yang-Mills Chern-Simons term, plus boundary term. The method is systematic and allows generalization of the Wess-Zumino-Witten term to theories of extra dimensions, and to express it in alternative and more compact forms. We give a novel form appropriate to the case of (unintegrated) massless fermions.Comment: 25 pages, 1 figure; minor errors fixe

Perceptual Experience

This book offers an account of perceptual experience—its intrinsic nature, its engagement with the world, its relations to mental states of other kinds, and its role in epistemic norms. One of the book’s main claims is that perceptual experience constitutively involves representations of worldly items. A second claim is that the relevant form of representation can be explained in broadly biological terms. After defending these foundational doctrines, the book proceeds to give an account of perceptual appearances and how they are related to the objective world. Appearances turn out to be relational, viewpoint dependent properties of external objects. There is also a complementary account of how the objects that possess these properties are represented. Another major concern is the phenomenological dimension of perception. The book maintains that perceptual phenomenology can be explained reductively in terms of the representational contents of experiences, and it uses this doctrine to undercut the traditional arguments for dualism. This treatment of perceptual phenomenology is then expanded to encompass cognitive phenomenology, the phenomenology of moods and emotions, and the phenomenology of pain. The next topic is the various forms of consciousness that perceptual experience can possess. A principal aim is to show that phenomenology is metaphysically independent of these forms of consciousness, and another is to de-mystify the form known as phenomenal consciousness. The book concludes by discussing the relations of various kinds that perceptual experiences bear to higher level cognitive states, including relations of format, content, and justification or support

Insects: Still looking like zombies

In arguing that insect brains are capable of sentience, Klein & Barron rely heavily on Bjorn Merker’s claim that activity in the human mid-brain is sufficient for conscious experience. I criticize Merker’s claim by pointing out that the behaviors supported by midbrain activity are much more primitive than the ones that appear to depend on consciousness. I raise a similar objection to Klein & Barron’s contention that insect behaviors are similar to behaviors that manifest consciousness in human beings. The similarity is weak. I also respond to the related view that integrative activity in mid-brain structures is sufficient to explain the sensory integration that characterizes human perceptual experience. There is good reason to think that the cortex makes additional contributions to experiential integration

Perceptual Experience

This book offers an account of perceptual experience—its intrinsic nature, its engagement with the world, its relations to mental states of other kinds, and its role in epistemic norms. One of the book’s main claims is that perceptual experience constitutively involves representations of worldly items. A second claim is that the relevant form of representation can be explained in broadly biological terms. After defending these foundational doctrines, the book proceeds to give an account of perceptual appearances and how they are related to the objective world. Appearances turn out to be relational, viewpoint dependent properties of external objects. There is also a complementary account of how the objects that possess these properties are represented. Another major concern is the phenomenological dimension of perception. The book maintains that perceptual phenomenology can be explained reductively in terms of the representational contents of experiences, and it uses this doctrine to undercut the traditional arguments for dualism. This treatment of perceptual phenomenology is then expanded to encompass cognitive phenomenology, the phenomenology of moods and emotions, and the phenomenology of pain. The next topic is the various forms of consciousness that perceptual experience can possess. A principal aim is to show that phenomenology is metaphysically independent of these forms of consciousness, and another is to de-mystify the form known as phenomenal consciousness. The book concludes by discussing the relations of various kinds that perceptual experiences bear to higher level cognitive states, including relations of format, content, and justification or support

Anomaly mediated neutrino-photon interactions at finite baryon density

We propose new physical processes based on the axial vector anomaly and described by the Wess-Zumino-Witten term that couples the photon, Z-boson, and the omega-meson. The interaction takes the form of a pseudo-Chern-Simons term, $\sim \epsilon_{\mu\nu\rho\sigma}\omega^\mu Z^\nu F^{\rho\sigma}$. This term induces neutrino-photon interactions at finite baryon density via the coupling of the Z-boson to neutrinos. These interactions may be detectable in various laboratory and astrophysical arenas. The new interactions may account for the MiniBooNE excess. They also produce a competitive contribution to neutron star cooling at temperatures >10^9 K. These processes and related axion--photon interactions at finite baryon density appear to be relevant in many astrophysical regimes.Comment: 4 pages, 2 figures; references adde

Methods for evaluating the performance of volume phase holographic gratings for the VIRUS spectrograph array

The Visible Integral Field Replicable Unit Spectrograph (VIRUS) is an array of at least 150 copies of a simple, fiber-fed integral field spectrograph that will be deployed on the Hobby-Eberly Telescope (HET) to carry out the HET Dark Energy Experiment (HETDEX). Each spectrograph contains a volume phase holographic grating as its dispersing element that is used in first order for 350 nm to 550 nm. We discuss the test methods used to evaluate the performance of the prototype gratings, which have aided in modifying the fabrication prescription for achieving the specified batch diffraction efficiency required for HETDEX. In particular, we discuss tests in which we measure the diffraction efficiency at the nominal grating angle of incidence in VIRUS for all orders accessible to our test bench that are allowed by the grating equation. For select gratings, these tests have allowed us to account for > 90% of the incident light for wavelengths within the spectral coverage of VIRUS. The remaining light that is unaccounted for is likely being diffracted into reflective orders or being absorbed or scattered within the grating layer (for bluer wavelengths especially, the latter term may dominate the others). Finally, we discuss an apparatus that will be used to quickly verify the first order diffraction efficiency specification for the batch of at least 150 VIRUS production gratings.Comment: 18 pages, 11 figures. To be published in Proc. SPIE, 2012, "Ground-Based and Airborne Instrumentation for Astronomy IV", 8446-20