Generic dijet soft functions at two-loop order: correlated emissions

We present a systematic algorithm for the perturbative computation of soft functions that are defined in terms of two light-like Wilson lines. Our method is based on a universal parametrisation of the phase-space integrals, which we use to isolate the singularities in Laplace space. The observable-dependent integrations can then be performed numerically, and they are implemented in the new, publicly available package SoftSERVE that we use to derive all of our numerical results. Our algorithm applies to both SCET-1 and SCET-2 soft functions, and in the current version it can be used to compute two out of three NNLO colour structures associated with the so-called correlated-emission contribution. We confirm existing two-loop results for about a dozen $e^+e^-$ and hadron-collider soft functions, and we obtain new predictions for the C-parameter as well as thrust-axis and broadening-axis angularities.Comment: 58 pages, 8 figures, associated package can be found at https://softserve.hepforge.org/. Minor revisio

Biofouling Effects on the Response of a Wave Measurement Buoy in Deep Water

AbstractThe effects of biofouling on a wave measurement buoy are examined using concurrent data collected with two Datawell Waveriders at Ocean Station P: one heavily biofouled at the end of a 26-month deployment, the other newly deployed and clean. The effects are limited to the high-frequency response of the buoy and are correctly diagnosed with the spectral “check factors” that compare horizontal and vertical displacements. A simple prediction for the progressive change in frequency response during biofouling reproduces the check factors over time. The bulk statistical parameters of significant wave height, peak period, average period, and peak direction are only slightly affected by the biofouling because the contaminated frequencies have very low energy throughout the comparison dataset.</jats:p

Froggatt-Nielsen Meets the SMEFT

We study the matching of Froggatt-Nielsen theories of flavour onto the Standard Model Effective Field Theory (SMEFT), upon integrating out a heavy Beyond-the-Standard-Model (BSM) scalar `flavon' whose vacuum expectation value breaks an Abelian flavour symmetry at energies $\Lambda_\text{FN}$ well above the electroweak scale, $\Lambda_\text{FN} > \Lambda_\text{SM}$. We include matching contributions to the infrared $d_\text{SM}=6$ (Warsaw basis) SMEFT sourced from ultraviolet contact terms suppressed up to order $1 / \Lambda_\text{UV}^2$ in the Froggatt-Nielsen Lagrangian, where $\Lambda_\text{UV} > \Lambda_\text{FN}$ is an arbitrary deep-ultraviolet scale where further unspecified BSM particles are dynamical. This includes tree-level (one-loop) ultraviolet diagrams with $d_{\text{FN}}=6$ $(5)$ effective vertices. We first do so with a toy model, but then generalize our findings to arbitrary Frogatt-Nielsen charges. Our results indicate a rich and non-trivial signature of Froggatt-Nielsen theories on the (otherwise) model-independent operators of the SMEFT, and we briefly speculate on extending our analysis to broader classes of BSM flavour models, e.g. non-Abelian and/or gauged theories. We thus take an important step towards determining how to use rapidly developing theoretical and experimental SMEFT technologies to gain unambiguous insight into the SM's longstanding fermion flavour puzzle.Comment: 49 pages, 5 figure

No-go limitations on UV completions of the Neutrino Option

We discuss the possible origin of the Majorana mass scale(s) required for the "Neutrino Option" where the electroweak scale is generated simultaneously with light neutrino masses in a type-I seesaw model, by common dimension four interactions. We establish no-go constraints on the perturbative generation of the Majorana masses required due to global symmetries of the seesaw Lagrangian.Comment: 6 pages, 3 figures. Matches published versio

Automated Calculation of Dijet Soft Functions in the Presence of Jet Clustering Effects

We extend our framework for the automated calculation of dijet soft functions to observables that do not obey the non-Abelian exponentiation theorem, like jet-veto or grooming soft functions that are sensitive to clustering effects of the jet algorithm. Although the matrix element for uncorrelated double emissions has a simpler structure than the one for correlated emissions, we argue that its singularity structure poses more stringent constraints on the required phase-space parametrisation. Our algorithm applies to both SCET-1 and SCET-2 soft functions and it is implemented in the novel program SoftSERVE. We present results for various jet-veto observables and obtain new predictions for the soft-drop jet-grooming algorithm.Comment: 7 pages, 3 figures; to appear in the proceedings of the 13th International Symposium on Radiative Corrections (Radcor 2017), 24-29 September 2017, St. Gilgen, Austri