David Lopez Mateos

Towards a holographic dual of large N(c) QCD

We study N f D6-brane probes in the supergravity background dual to N c D4-branes compactified on a circle with supersymmetry-breaking boundary conditions. In the limit in which the resulting Kaluza-Klein modes decouple, the gauge theory reduces to non-supersymmetric, four-dimensional QCD with N c colours and N f 0, obeying the Gell-Mann-Oakes-Renner relation: M π 2 = −m q ψ/fπ2 . In the case 1

A Supersymmetric Black Ring

> N f>1 we provide a holographic version of the Vafa-Witten theorem, which states that the U(N f) flavour symmetry cannot be spontaneously broken. Further, we find N f 2−1 unexpectedly light pseudo-scalar mesons in the spectrum. We argue that these are not (pseudo-)Goldstone bosons and speculate on the string mechanism responsible for their lightness. We then study the theory at finite temperature and exhibit a phase transition associated with a discontinuity in ψ(T). D6/ pairs are also briefly discussed.

Supersymmetric black rings and three-charge supertubes

A new supersymmetric black hole solution of five-dimensional supergravity is presented. It has an event horizon of topology S1 x S2. This is the first example of a supersymmetric, asymptotically flat black hole of nonspherical topology. The solution is uniquely specified by its electric charge and two independent angular momenta. These conserved charges can be arbitrarily close, but not exactly equal, to those of a supersymmetric black hole of spherical topology.

An open string landscape

We present supergravity solutions for

Supersymmetric 4D rotating black holes from 5D black rings

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Microscopic entropy of the black ring.

-supersymmetric black supertubes with three charges and three dipoles. Their reduction to five dimensions yields supersymmetric black rings with regular horizons and two independent angular momenta. The general solution contains seven independent parameters and provides the first example of nonuniqueness of supersymmetric black holes. In ten dimensions, the solutions can be realized as D1-D5-P black supertubes. We also present a worldvolume construction of a supertube that exhibits three dipoles explicitly. This description allows an arbitrary cross section but captures only one of the angular momenta.

The holographic life of the η

The effect of fluxes on open string moduli is studied by analyzing the constraints imposed by supersymmetry on D-branes in type IIB flux backgrounds. We show that generically the conditions of supersymmetry cannot be maintained when moving along the geometrical moduli space of the brane, so that open string moduli are lifted. We argue that there is a disconnected and discrete set of supersymmetric solutions to the open string equations of motion, which extends the familiar closed string landscape to the open string sector.

HOLOGRAPHIC MESONS: ADDING FLAVOR TO THE ADS/CFT DUALITY

We present supersymmetric solutions describing black holes with non-vanishing angular momentum in four dimensional asymptotically flat space. The solutions are obtained by Kaluza-Klein reduction of five-dimensional supersymmetric black rings wrapped on the fiber of a Taub-NUT space. We show that in the four-dimensional description the singularity of the nut can be hidden behind a regular black hole event horizon and thereby obtain an explicit example of a non-static multi-black hole solution in four asymptotically flat dimensions.

Oscillator level for black holes and black rings

A surprising new seven-parameter supersymmetric black ring solution of five-dimensional supergravity has recently been discovered. In this paper, M theory is used to give an exact microscopic accounting of its entropy.

Measurement of the ZZ production cross section in pp collisions at s√ = 8 TeV using the ZZ→ℓ−ℓ+ℓ′−ℓ′+ and ZZ→ℓ−ℓ+νν¯ channels with the ATLAS detector

In the string holographic dual of large-Nc QCD with Nf ∞avours of (1), the · 0 meson is massless at inflnite Nc and dual to a collective ∞uctuation of Nf D6-brane probes in a supergravity background. Here we identify the string diagrams responsible for the gen- eration of a mass of order Nf=Nc, consistent with the Witten-Veneziano formula, and show that the supergravity limit of these diagrams corresponds to mixings with pseudoscalar glueballs. We argue that the dependence on the µ-angle in the supergravity description occurs only through the combination µ + 2 p Nf· 0 =f…, as dictated by the U(1)A anomaly. We provide a quantitative test by computing the linear term in the · 0 potential in two independent ways, with perfect agreement.