Varun Vaidya

Constraints on Galactic Wino Densities from Gamma Ray Lines

A bstractWe systematically compute the annihilation rate for neutral winos into the final state γ + X, including all leading radiative corrections. This includes both the Sommerfeld enhancement (in the decoupling limit for the Higgsino) and the resummation of the leading electroweak double logarithms. Adopting an analysis of the HESS experiment, we place constraints on the mass as a function of the wino fraction of the dark matter and the shape of the dark matter profile. We also determine how much coring is needed in the dark matter halo to make the wino a viable candidate as a function of its mass. Additionally, as part of our effective field theory formalism, we show that in the pure-Standard Model sector of our theory, emissions of soft Higgses are power-suppressed and that collinear Higgs emission does not contribute to leading double logs.

The Higgs transverse momentum distribution at NNLL and its theoretical errors

A bstractIn this letter, we present the NNLL-NNLO transverse momentum Higgs distribution arising from gluon fusion. In the regime p⊥ ≪ mh we include the resummation of the large logs at next to next-to leading order and then match on to the αs2 fixed order result near p⊥ ∼ mh. By utilizing the rapidity renormalization group (RRG) we are able to smoothly match between the resummed, small p⊥ regime and the fixed order regime. We give a detailed discussion of the scale dependence of the result including an analysis of the rapidity scale dependence. Our central value differs from previous results, in the transition region as well as the tail, by an amount which is outside the error band. This difference is due to the fact that the RRG profile allows us to smoothly turn off the resummation.

Calculating the Annihilation Rate of Weakly Interacting Massive Particles

We develop a formalism that allows one to systematically calculate the WIMP annihilation rate into gamma rays whose energy far exceeds the weak scale. A factorization theorem is presented which separates the radiative corrections stemming from initial state potential interactions from loops involving the final state. This separation allows us to go beyond the fixed order calculation, which is polluted by large infrared logarithms. For the case of Majorana WIMPs transforming in the adjoint representation of SU(2), we present the result for the resummed rate at leading double log accuracy in terms of two initial state partial wave matrix elements and one hard matching coefficient. For a given model, one may calculate the cross section by finding the tree level matching coefficient and determining the value of a local four-fermion operator. The effects of resummation can be as large as 100% for a 20 TeV WIMP. The generalization of the formalism to other types of WIMPs is discussed.

Semi-inclusive wino and higgsino annihilation to LL ′

A bstractWe systematically compute the annihilation rate for winos and higgsinos into the final state relevant for indirect detection experiments, γ + X. The radiative corrections to this process receive enhancement from the large Bloch-Nordsieck-Violating Sudakov logarithm, log(2Mχ/MW ). We resum the double logs and include single logs to fixed order using a formalism that combines nonrelativistic and soft-collinear effective field theories. For the wino case, we update an earlier exclusion adapting results of the HESS experiment. At the thermal relic mass of 3 TeV, LL′ corrections result in a ∼30% reduction in rate relative to LL. Nonetheless, single logs do not save the wino, and it is still excluded by an order of magnitude. Experimental cuts produce an endpoint region which, our results show, significantly effects the higgsino rate at its thermal-relic mass near 1 TeV and is deserving of further study.

Gravitational spin Hamiltonians from the S matrix

We utilize generalized unitarity and recursion relations combined with effective field theory(EFT) techniques to compute spin dependent interaction terms for inspiralling binary systems in the post newtonian(PN) approximation. Using these methods offers great computational advantage over traditional techniques involving feynman diagrams, especially at higher orders in the PN expansion. As a specific example, we reproduce the spin-orbit interaction up to 2.5 PN order as also the leading order

The Story of WINO Dark Matter

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Hunting for Heavy Winos in the Galactic Center

(3PN) hamiltonian for an arbitrary massive object. We also obtain the unknown

Emergent and broken symmetries of atomic self-organization arising from Gouy phase shifts in multimode cavity QED.

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Precision Photon Spectra for Wino Annihilation

(3.5PN) spin hamiltonian for an arbitrary massive object in terms of its low frequency linear response to gravitational perturbations, which was till now known only for a black hole. Furthermore, we derive the missing

Soft evolution after a hard scattering process

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