We use a variant of the D4-D8 construction that includes two chiral and one heavy meson, to describe heavy-light baryons and their exotics as heavy mesons bound to a flavor instanton in bulk. At strong coupling, the heavy meson is shown to always bind in the form of a flavor instanton zero mode in the fundamental representation. The ensuing instanton moduli for the heavy baryons exhibits both chiral and heavy quark symmetry. We detail how to quantize it, and derive model independent mass relations for heavy bayons with a single-heavy quark in leading order, in overall agreement with the reported baryonic spectra with one charm or bottom. We also discuss the low-lying masses and quantum assignments for the even and odd parity states, some of which are yet to be observed. We extend our analysis to double-heavy pentaquarks with hidden charm and bottom. In leading order, we find a pair of doube-heavy iso-doublets with IJ π = 1 2 1 2 − , 1 2 3 2 − assignments for all heavy flavor combinations. We also predict five new Delta-like pentaquark states with IJ π = 3 2 1 2 − , 3 2 3 2 − , 3 2 5 2 − assignments for both charm and bottom.

We construct a classical solution of vacuum string field theory (VSFT) and study whether it represents the perturbative open string vacuum. Our solution is given as a squeezed state in the Siegel gauge, and it fixes the arbitrary coefficients in the BRST operator in VSFT. We identify the tachyon and massless vector states as fluctuation modes around the classical solution. The tachyon mass squared α ′ m 2 * hata@gauge.scphys.kyoto-u.ac.jp † kawano@hep-th.phys.s.u-tokyo.ac.jp * The descent relation has been studied in VSFT to give expected result under the assumption that the ghost parts of the classical solutions for Dp-branes with different p are common [10,11].

We study the noncommutative U͑2͒ monopole solution to second order in the noncommutativity parameter i j . We solve the BPS equation in noncommutative super Yang-Mills theory to O( 2 ), transform the solution to the commutative description by the Seiberg-Witten ͑SW͒ map, and evaluate the eigenvalues of the scalar field. We find that, by tuning the free parameters in the SW map, we can make the scalar eigenvalues precisely reproduce the configuration of a tilted D-string suspended between two parallel D3-branes. This gives an example of how the ambiguities inevitable in the higher order SW map are fixed by physical requirements.

We reveal a novel mathematical structure in physical observables, the mass of tachyon fluctuation mode and the energy density, associated with a classical solution of vacuum string field theory constructed previously [hep-th/0108150]. We find that they are expressed in terms of quantities which apparently vanish identically due to twist even-odd degeneracy of eigenvalues of a Neumann coefficient matrix defining the three-string interactions. However, they can give non-vanishing values because of the breakdown of the degeneracy at the edge of the eigenvalue distribution. We also present a general prescription of correctly simplifying the expressions of these observables. Numerical calculation of the energy density following our prescription indicates that the present classical solution represents the configuration of two D25-branes.

We investigate the variation of the string field action under changes of the string field vertices giving rise to different decompositions of the moduli spaces of Riemann surfaces. We establish that any such change in the string action arises from a field transformation canonical with respect to the Batalin-Vilkovisky (BV) antibracket, and find the explicit form of the generator of the infinitesimal transformations. Two theories using different decompositions of moduli space are shown to yield the same gauge fixed action upon use of different gauge fixing conditions. We also elaborate on recent work on the covariant BV formalism, and emphasize the necessity of a measure in the space of two dimensional field theories in order to extend a recent analysis of background independence to quantum string field theory.