14845325
Massive-scalar absorption by extremal p-branes
Abstract We study the absorption probability of minimally-coupled massive scalars by extremal p -branes. In particular, we find that the massive scalar wave equation under the self-dual string background has the same form as the massless scalar wave equation under the dyonic string background. Thus it can be cast into the form of a modified Mathieu equation and solved exactly. Another example that we can solve exactly is that of the D =4 two-charge black hole with equal charges, for which we obtain the closed-form absorption probability. We also obtain the leading-order absorption probabilities for D3-, M2- and M5-branes.
16148171
HARMONIC SUPERPOSITIONS OF NONEXTREMAL p-BRANES
The plot of allowed p and D values for p-brane solitons in D-dimensional supergravity is the same whether the solitons are extremal or nonextremal. One of the useful tools for relating different points on the plot is vertical dimensional reduction, which is possible if periodic arrays of p-brane solitons can be constructed. This is straightforward for extremal p-branes, since the no-force condition allows arbitrary multicenter solutions to be constructed in terms of a general harmonic function on the transverse space. This has also been shown to be possible in the special case of nonextremal black holes in D=4 arrayed along an axis. In this paper, we extend previous results to include multiscalar black holes, and dyonic black holes. We also consider their oxidation to higher dimensions, discuss general procedures for constructing the solutions and study their symmetries.
1234275
Supermembranes with fewer supersymmetries
Abstract The usual supermembrane solution of D = 11 supergravity interpolates between R 11 and AdS 4 × round R 7 , has symmetry P 3 × SO (8) and preserves 1 2 of the spacetime supersymmetries for either orientation of the round S 7 . Here we show that more general supermembrane solutions may be obtained by replacing the round S 7 by any seven-dimensional Einstein space M 7 . These have symmetry P 3 × G , where G is the isometry group of M 7 . For example, G = SO (5) × SO (3) for the squashed S 7 . For one orientation of M 7 , they preserve N 16 spacetime supersymmetries where 1 ≤ N ≤ 8 is the number of Killing spinors on M 7 ; for the opposite orientation they preserve no supersymmetries since then M 7 has no Killing spinors. For example N = 1 for the left-squashed S 7 owing to its G 2 Weyl holonomy, whereas N = 0 for the right-squashed S 7 . All these solutions saturate the same Bogomol'nyi bound between the mass and charge. Similar replacements of S D - p -2 by Einstein spaces M D - p -2 yield new super p -brane solutions in other spacetime dimensions D ≤ 11. In particular, simultaneous dimensional reduction of the above D = 11 supermembranes on S 1 leads to a new class of D = 10 elementary string solutions which also have fewer supersymmetries.
119258587
Killing spinors for the bosonic string
We obtain the effective action for the bosonic string with arbitrary Yang-Mills fields, up to the α' order, in general dimensions. The form of the action is determined by the requirement that the action admit well-defined Killing spinor equations, whose projected integrability conditions give rise to the full set of equations of motion. The success of the construction suggests that the hidden "pseudo-supersymmetry" associated with the Killing spinor equations may be a property of the bosonic string itself.
13891187
pp waves in AdS gauged supergravities and supernumerary supersymmetry
Purely gravitational pp waves in AdS backgrounds are described by the generalized Kaigorodov metrics, and they generically preserve (1/4) of the maximum supersymmetry allowed by the AdS spacetimes. We obtain (1/2) supersymmetric purely gravitational pp-wave solutions, in which the Kaigorodov component is set to zero. We construct pp waves in AdS gauged supergravities supported by a vector field. We find that the solutions in D=4 and D=5 can then preserve (1/2) of the supersymmetry. Like those in ungauged supergravities, the supernumerary supersymmetry imposes additional constraints on the harmonic function associated with the pp waves. These new backgrounds provide interesting novel features of the supersymmetry enhancement for the dual conformal field theory in the infinite-momentum frame.
16776096
New charged black holes in five dimensions
We obtain new stationary charged solutions of five-dimensional minimal supergravity. We first obtain purely dipole-charged solutions by extending a technique that we developed for five-dimensional Ricci-flat metrics in a previous paper, which could be viewed as being analogous to a four-dimensional construction by Demianski and Plebanski. The further introduction of electric charge is achieved by means of a solution-generating technique, which exploits the global symmetry of five-dimensional minimal supergravity reduced on a time-like direction to four dimensions. We present this procedure in detail, since it provides a particularly simple general way of adding charge to any stationary solution of five-dimensional minimal supergravity. The new charged solutions we obtain limit in special cases to black rings carrying electric and magnetic dipole charge, or to charged Myers–Perry rotating black holes. We analyze the general solutions in detail, showing that they can describe asymptotically locally flat black holes whose horizon is a lens space L(n; m) = S3/Γ(n; m). At infinity they approach Minkowski5/Γ(m; n).
43093269
Rare decays of the top quark in the one generation technicolor model.
The decays [ital t][r arrow][ital cV] ([ital V]=[gamma],[ital g],[ital Z]) and [ital t][r arrow][ital cP][sup 0] induced through loop processes are calculated in the Farhi-Susskind one family technicolor (TC) model. We find that these new contributions can enhance the SM branching fractions by as much as 3--4 orders of magnitude, i.e., [ital B]([ital t][r arrow][ital cg])[similar to]10[sup [minus]6], [ital B]([ital t][r arrow][ital cZ])[similar to]10[sup [minus]7], [ital B]([ital t][r arrow][ital c][gamma])[similar to]10[sup [minus]8], and [ital B]([ital t][r arrow][ital cP][sup 0])[similar to]10[sup [minus]9], for the favorable values of the parameters. It might provide a unique window to detect the virtual effects of pseudo Goldstone bosons in TC theory.