Three Body Interactions, Angular Momentum and Black Hole Moduli Spaces

We investigate the dynamics of a pair of (4+1)-dimensional black holes in the moduli approximation and with fixed angular momentum. We find that spinning black holes at small separations are described by the de Alfaro, Fubini and Furlan model. For more than two black holes, we find an explicit expression for the three-body interactions in the moduli metric by associating them with the one-loop three-point amplitude of a four-dimensional $\phi^3$ theory. We also investigate the dynamics of a three black hole system in various approximations.Comment: 20 pages, phyzz

Wilsonian Proof for Renormalizability of N=1/2 Supersymmetric Field Theories

We provide Wilsonian proof for renormalizability of four-dimensional quantum field theories with ${\cal N}=1/2$ supersymmetry. We argue that the non-hermiticity inherent to these theories permits assigning noncanonical scaling dimension both for the Grassman coordinates and superfields. This reassignment can be done in such a way that the non(anti)commutativity parameter is dimensionless, and then the rest of the proof ammounts to power counting. The renormalizability is also stable against adding standard four-dimensional soft-breaking terms to the theory. However, with the new scaling dimension assignments, some of these terms are not just relevant deformations of the theory but become marginal.Comment: 10 pages, no figure, v2: minor correctio

On the Numerical Evaluation of One-Loop Amplitudes: the Gluonic Case

We develop an algorithm of polynomial complexity for evaluating one-loop amplitudes with an arbitrary number of external particles. The algorithm is implemented in the Rocket program. Starting from particle vertices given by Feynman rules, tree amplitudes are constructed using recursive relations. The tree amplitudes are then used to build one-loop amplitudes using an integer dimension on-shell cut method. As a first application we considered only three and four gluon vertices calculating the pure gluonic one-loop amplitudes for arbitrary external helicity or polarization states. We compare our numerical results to analytical results in the literature, analyze the time behavior of the algorithm and the accuracy of the results, and give explicit results for fixed phase space points for up to twenty external gluons.Comment: 22 pages, 9 figures; v2: references added, version accepted for publicatio

Cash-on-hand in Developing Countries and the Value of Social Insurance: Evidence from Brazil

This paper first exploits a "bonus" policy providing low-income workers with cash grants in Brazil to study the effect of liquidity provision on unemployment outcomes. Based on a RD Design, I find that granting unemployed workers with a bonus equal to half of their previous monthly earnings decreases the probability of exiting unemployment within 8 weeks by around 0.65%. Second, by exploiting the UI potential duration schedule, I find that granting workers with an extra month of unemployment benefits decreases the same outcome by 1.9%. Then, theoretical results from Landais (2014) are used to combine these estimates and disentangle liquidity and moral hazard effects of UI. Based on these, I estimate the liquidity-to-moral hazard ratio in Brazil to be as large as 98%, similarly to values previously found in the US. It suggests that, contrary to common belief, providing UI in developing countries with large informal labor markets may yield substantial welfare gains

Closed-Form Decomposition of One-Loop Massive Amplitudes

We present formulas for the coefficients of 2-, 3-, 4- and 5-point master integrals for one-loop massive amplitudes. The coefficients are derived from unitarity cuts in D dimensions. The input parameters can be read off from any unitarity-cut integrand, as assembled from tree-level expressions, after simple algebraic manipulations. The formulas presented here are suitable for analytical as well as numerical evaluation. Their validity is confirmed in two known cases of helicity amplitudes contributing to gg -> gg and gg -> gH, where the masses of the Higgs and the fermion circulating in the loop are kept as free parameters.Comment: 37 page

Integrand reduction of one-loop scattering amplitudes through Laurent series expansion

We present a semi-analytic method for the integrand reduction of one-loop amplitudes, based on the systematic application of the Laurent expansions to the integrand-decomposition. In the asymptotic limit, the coefficients of the master integrals are the solutions of a diagonal system of equations, properly corrected by counterterms whose parametric form is konwn a priori. The Laurent expansion of the integrand is implemented through polynomial division. The extension of the integrand-reduction to the case of numerators with rank larger than the number of propagators is discussed as well.Comment: v2: Published version: references and two appendices added. v3: Eq.(6.11) corrected, Appendix B updated accordingl

Fermi-LAT Observations of the 2014 May-July outburst from 3C 454.3

A prominent outburst of the flat spectrum radio quasar 3C~454.3 was observed in 2014 June with the \emph{Fermi} Large Area Telescope. This outburst was characterized by a three-stage light-curve pattern---plateau, flare and post-flare---that occurred from 2014 May to July, in a similar pattern as observed during the exceptional outburst in 2010 November. The highest flux of the outburst reported in this paper occurred during 2014 June 7--29, showing a multiple-peak structure in the light-curves. The average flux in these 22 days was found to be $F[E > 100~\mathrm{MeV}] = (7.2 \pm 0.2) \times 10^{-6}$~ph~cm$^{-2}$~s$^{-1}$, with a spectral index, for a simple power law, of $\Gamma = 2.04 \pm 0.01$. That made this outburst the first $\gamma$-ray high state of 3C~454.3 ever to be detected by \emph{Fermi} with such a hard spectrum over several days. The highest flux was recorded on 2014 June 15, in a 3 hr bin, at MJD 56823.5625, at a level of $F[E > 100~\mathrm{MeV}] = (17.6 \pm 1.9) \times 10^{-6}$~ph~cm$^{-2}$~s$^{-1}$. The rise time of one of the short subflares was found to be $T_r= 1200 \pm 700$~s at MJD = 56827, when the flux increased from 4 to 12 $\times 10^{-6}$~ph~cm$^{-2}$~s$^{-1}$. Several photons above 20 GeV were collected during this outburst, including one at 45 GeV on MJD 56827, constraining the $\gamma$-ray emission region to be located close to the outer boundary of the broad-line region, leading to fast flux variability.Comment: Accepted for publication in {\sc the astrophysical journal}: 2016 July 12}; 15 pages, 7 figures, 6 table

Single Cut Integration

We present an analytic technique for evaluating single cuts for one-loop integrands, where exactly one propagator is taken to be on shell. Our method extends the double-cut integration formalism of one-loop amplitudes to the single-cut case. We argue that single cuts give meaningful information about amplitudes when taken at the integrand level. We discuss applications to the computation of tadpole coefficients.Comment: v2: corrected typo in abstrac