Nonholomorphic N=2 terms in N=4 SYM: 1-Loop Calculation in N=2 superspace

The effective action of N=2 gauge multiplets in general includes higher-dimension UV finite nonholomorphic corrections integrated with the full N=2 superspace measure. By adding a hypermultiplet in the adjoint representation we study the effective action of N=4 SYM. The nonanomalous SU(4) R-symmetry of the classical N=4 theory must be also present in the on-shell effective action, and therefore we expect to find similar nonholomorphic terms for each of the scalars in the hypermultiplet. The N=2 path integral quantization formalism developed in projective superspace allows us to compute these hypermultiplet nonholomorphic terms directly in N=2 superspace. The corresponding gauge multiplet expression can be successfully compared with the result inferred from a N=1 calculation in the abelian subsector.Comment: 12 pages, LaTex, includes 4 .eps figures, sign convention in path integral definition changed, sign of nonholomorphic potential change

Higher Derivative F-terms in N=2 Strings

We study a special class of higher derivative F-terms of the form $F_{g,n}W^{2g}(\Pi f)^{n}$ where W is the N=2 gravitational superfield and $\Pi$ is the chiral projector applied to a non-holomorphic function $f$ of the heterotic dilaton vector superfield. We analyze these couplings in the heterotic theory on $K3\times T^2$ , where it is found they satisfy an anomaly equation as the well studied $F_{g,0}$ terms. We recognize that, near a point of SU(2) enhancement, a given generating function of the leading singularity of the $F_{g,n}$ reproduces the free energy of a c=1 string at an arbitrary radius R. According to the N=2 heterotic-type II duality in 4d, we then study these couplings near a conifold singularity, using its local description in terms of intersecting D-5-branes. In this context, it turns out that there exists, among the other states involved, a vector gauge field reproducing the heterotic leading singularity structure.Comment: 19 pages, latex file, no figure

Tensor hierarchies, Borcherds algebras and E11

Gauge deformations of maximal supergravity in D=11-n dimensions generically give rise to a tensor hierarchy of p-form fields that transform in specific representations of the global symmetry group E(n). We derive the formulas defining the hierarchy from a Borcherds superalgebra corresponding to E(n). This explains why the E(n) representations in the tensor hierarchies also appear in the level decomposition of the Borcherds superalgebra. We show that the indefinite Kac-Moody algebra E(11) can be used equivalently to determine these representations, up to p=D, and for arbitrarily large p if E(11) is replaced by E(r) with sufficiently large rank r.Comment: 22 pages. v2: Published version (except for a few minor typos detected after the proofreading, which are now corrected

On N=2 low energy effective actions

We propose a Wilsonian action compatible with special geometry and higher dimension N=2 corrections, and show that the holomorphic contribution F to the low energy effective action is independent of the infrared cutoff. We further show that for asymptotically free SU(2) super Yang-Mills theories, the infrared cutoff can be tuned to cancel leading corrections to F. We also classify all local higher-dimensional contributions to the N=2 superspace effective action that produce corrections to the Kahler potential when reduced to N=1 superspace.Comment: 9 pages, Late

The Gaugings of Maximal D=6 Supergravity

We construct the most general gaugings of the maximal D=6 supergravity. The theory is (2,2) supersymmetric, and possesses an on-shell SO(5,5) duality symmetry which plays a key role in determining its couplings. The field content includes 16 vector fields that carry a chiral spinor representation of the duality group. We utilize the embedding tensor method which determines the appropriate combinations of these vectors that participate in gauging of a suitable subgroup of SO(5,5). The construction also introduces the magnetic duals of the 5 two-form potentials and 16 vector fields.Comment: 34 pages, latex, reference added, typo's corrected and minor improvements mad

Strong Couplings of X(3872)_{J=1,2} and a New Look at J/psi Suppression in Heavy Ion Collisions

We define and compute from data the strong couplings of the X(3872) with both of the possible quantum numbers assignments J^{PC}=1^{++},2^{-+}. We use these to compute cross sections for J/psi resonance scattering into D Dbar*. As an application of the results obtained we revise the calculation of the J/psi absorption in a hot hadron gas to confront with recent RHIC observations in Au-Au collisions.Comment: 23 pages, 18 figures, 4 table

A Note on E11 and Three-dimensional Gauged Supergravity

We determine the gauge symmetries of all p-forms in maximal three-dimensional gauged supergravity by requiring invariance of the Lagrangian. It is shown that in a particular ungauged limit these symmetries are in precise correspondence to those predicted by the very-extended Kac-Moody algebra E11. We demonstrate that whereas in the ungauged limit the bosonic gauge algebra closes off-shell, the closure is only on-shell in the full gauged theory. This underlines the importance of dynamics for understanding the Kac-Moody origin of the symmetries of gauged supergravity.Comment: Published versio

DgCox: a differential geometric approach for high-dimensional Cox proportional hazard models

Many clinical and epidemiological studies rely on survival modelling to detect clinically relevant factors that affect various event histories. With the introduction of high-throughput technologies in the clinical and even large-scale epidemiological studies, the need for inference tools that are able to deal with fat data-structures, i.e., relatively small number of observations compared to the number of features, is becoming more prominent. This paper will introduce a principled sparse inference methodology for proportional hazards modelling, based on differential geometrical analyses of the high-dimensional likelihood surface