# Publications

## Index Formulae for Line Bundle Cohomology on Complex Surfaces

FORTSCHRITTE DER PHYSIK-PROGRESS OF PHYSICS **68** (2020) ARTN 1900086

## A Search for MeV to TeV Neutrinos from Fast Radio Bursts with IceCube

The Astrophysical Journal: an international review of astronomy and astronomical physics American Astronomical Society (2020)

We present two searches for IceCube neutrino events coincident with 28 fast radio bursts (FRBs) and one repeating FRB. The first improves upon a previous IceCube analysis -- searching for spatial and temporal correlation of events with FRBs at energies greater than roughly 50 GeV -- by increasing the effective area by an order of magnitude. The second is a search for temporal correlation of MeV neutrino events with FRBs. No significant correlation is found in either search, therefore, we set upper limits on the time-integrated neutrino flux emitted by FRBs for a range of emission timescales less than one day. These are the first limits on FRB neutrino emission at the MeV scale, and the limits set at higher energies are an order-of-magnitude improvement over those set by any neutrino telescope.

## Machine Learning Line Bundle Cohomology

FORTSCHRITTE DER PHYSIK-PROGRESS OF PHYSICS **68** (2020) ARTN 1900087

## Analytic results for deep-inelastic scattering at NNLO QCD with the nested soft-collinear subtraction scheme

EUROPEAN PHYSICAL JOURNAL C **80** (2020)

## Time-integrated Neutrino Source Searches with 10 years of IceCube Data

Physical Review Letters American Physical Society (2020)

This paper presents the results from point-like neutrino source searches using ten years of IceCube data collected between Apr.~6, 2008 and Jul.~10, 2018. We evaluate the significance of an astrophysical signal from a point-like source looking for an excess of clustered neutrino events with energies typically above $\sim1\,$TeV among the background of atmospheric muons and neutrinos. We perform a full-sky scan, a search within a selected source catalog, a catalog population study, and three stacked Galactic catalog searches. The most significant point in the Northern hemisphere from scanning the sky is coincident with the Seyfert II galaxy NGC 1068, which was included in the source catalog search. The excess at the coordinates of NGC 1068 is inconsistent with background expectations at the level of $2.9\,\sigma$ after accounting for statistical trials. The combination of this result along with excesses observed at the coordinates of three other sources, including TXS 0506+056, suggests that, collectively, correlations with sources in the Northern catalog are inconsistent with background at 3.3$\,\sigma$ significance. These results, all based on searches for a cumulative neutrino signal integrated over the ten years of available data, motivate further study of these and similar sources, including time-dependent analyses, multimessenger correlations, and the possibility of stronger evidence with coming upgrades to the detector.

## Heterotic instantons for monad and extension bundles

Journal of High Energy Physics Springer Science and Business Media LLC **2020** (2020) 81

## Development of an analysis to probe the neutrino mass ordering with atmospheric neutrinos using three years of IceCube DeepCore data: IceCube Collaboration

European Physical Journal C **80** (2020)

© 2020, The Author(s). The Neutrino Mass Ordering (NMO) remains one of the outstanding questions in the field of neutrino physics. One strategy to measure the NMO is to observe matter effects in the oscillation pattern of atmospheric neutrinos above ∼1GeV, as proposed for several next-generation neutrino experiments. Moreover, the existing IceCube DeepCore detector can already explore this type of measurement. We present the development and application of two independent analyses to search for the signature of the NMO with three years of DeepCore data. These analyses include a full treatment of systematic uncertainties and a statistically-rigorous method to determine the significance for the NMO from a fit to the data. Both analyses show that the dataset is fully compatible with both mass orderings. For the more sensitive analysis, we observe a preference for normal ordering with a p-value of pIO= 15.3 % and CL s= 53.3 % for the inverted ordering hypothesis, while the experimental results from both analyses are consistent within their uncertainties. Since the result is independent of the value of δCP and obtained from energies Eν≳5GeV, it is complementary to recent results from long-baseline experiments. These analyses set the groundwork for the future of this measurement with more capable detectors, such as the IceCube Upgrade and the proposed PINGU detector.

## Algorithms and tools for iterated Eisenstein integrals

Journal of High Energy Physics Springer Science and Business Media LLC **2020** (2020) 105

## Design and Performance of the first IceAct Demonstrator at the South Pole

Journal of Instrumentation IOP Publishing (2020)

In this paper we describe the first results of a compact imaging air-Cherenkov telescope, IceAct, operating in coincidence with the IceCube Neutrino Observatory (IceCube) at the geographic South Pole. An array of IceAct telescopes (referred to as the IceAct project) is under consideration as part of the IceCube-Gen2 extension to IceCube. Surface detectors in general will be a powerful tool in IceCube-Gen2 for distinguishing astrophysical neutrinos from the dominant backgrounds of cosmic-ray induced atmospheric muons and neutrinos: the IceTop array is already in place as part of IceCube, but has a high energy threshold. Although the duty cycle will be lower for the IceAct telescopes than the present IceTop tanks, the IceAct telescopes may prove to be more effective at lowering the detection threshold for air showers. Additionally, small imaging air-Cherenkov telescopes in combination with IceTop, the deep IceCube detector or other future detector systems might improve measurements of the composition of the cosmic ray energy spectrum. In this paper we present measurements of a first 7-pixel imaging air Cherenkov telescope demonstrator, proving the capability of this technology to measure air showers at the South Pole in coincidence with IceTop and the deep IceCube detector.

## Search for PeV Gamma-Ray Emission from the Southern Hemisphere with 5 Years of Data from the IceCube Observatory

The Astrophysical Journal: an international review of astronomy and astronomical physics American Astronomical Society (2020)

The measurement of diffuse PeV gamma-ray emission from the Galactic plane would provide information about the energy spectrum and propagation of Galactic cosmic rays, and the detection of a point-like source of PeV gamma rays would be strong evidence for a Galactic source capable of accelerating cosmic rays up to at least a few PeV. This paper presents several un-binned maximum likelihood searches for PeV gamma rays in the Southern Hemisphere using 5 years of data from the IceTop air shower surface detector and the in-ice array of the IceCube Observatory. The combination of both detectors takes advantage of the low muon content and deep shower maximum of gamma-ray air showers, and provides excellent sensitivity to gamma rays between $\sim$0.6 PeV and 100 PeV. Our measurements of point-like and diffuse Galactic emission of PeV gamma rays are consistent with background, so we constrain the angle-integrated diffuse gamma-ray flux from the Galactic Plane at 2 PeV to $2.61 \times 10^{-19}$ cm$^{-2}$ s$^{-1}$ TeV$^{-1}$ at 90% confidence, assuming an E$^{-3}$ spectrum, and we estimate 90% upper limits on point-like emission at 2 PeV between 10$^{-21}$ - 10$^{-20}$ cm$^{-2}$ s$^{-1}$ TeV$^{-1}$ for an E$^{-2}$ spectrum, depending on declination. Furthermore, we exclude unbroken power-law emission up to 2 PeV for several TeV gamma-ray sources observed by H.E.S.S., and calculate upper limits on the energy cutoffs of these sources at 90% confidence. We also find no PeV gamma rays correlated with neutrinos from IceCube's high-energy starting event sample. These are currently the strongest constraints on PeV gamma-ray emission.

## Is there really a `Hubble tension'?

arXiv (2019)

Errors in redshift measurements as small as $\Delta z \sim 0.0001$ can have significant impact on the value of inferred cosmological parameters such as $H_0$ (Davis et al. 2019). We have earlier reported that the redshifts of over 100 Type Ia supernovae (SNe Ia) which are in common between the SDSSII-SNLS3 Joint Lightcurve Analysis (JLA) catalogue (Betoule et al. 2014) and the subsequent Pantheon compilation (Scolnic et al. 2018) are discrepant - some by as much as $\Delta z \sim 0.1$ (Rameez 2019a). We study the impact of this on the inferred value of $H_0$ using calibrations of the supernova absolute magnitude via the 'local distance ladder' (Riess et al. 2016). For supernovae with $\Delta z > 0.025$, the JLA redshifts favour $H_0 \sim 72$~km~s$^{-1}$Mpc$^{-1}$, while the Pantheon redshifts favour $H_0 \sim 68$~km~s$^{-1}$Mpc$^{-1}$. For comparison the value inferred (assuming the flat $\Lambda$CDM model) from the Planck data on CMB anisotropies is $H_0 \sim 67.4 \pm 0.5$~km~s$^{-1}$Mpc$^{-1}$ (Aghanim et al. 2018). Thus the systematic uncertainties that apparently still plague the distance ladder measurement of $H_0$ undermine the significance of the discrepancy claimed by Riess et al. (2019).

## Quark beam function at next-to-next-to-next-to-leading order in perturbative QCD in the generalized large-N-c approximation

PHYSICAL REVIEW D **100** (2019) ARTN 114034

## Evidence for anisotropy of cosmic acceleration

Astronomy and Astrophysics: a European journal EDP Sciences (2019)

Observations reveal a `bulk flow' in the local Universe which is faster and extends to much larger scales than is expected around a typical observer in the standard $\Lambda$CDM cosmology. This is expected to result in a scale-dependent dipolar modulation of the acceleration of the expansion rate inferred from observations of objects within the bulk flow. From a maximum-likelihood analysis of the Joint Lightcurve Analysis (JLA) catalogue of Type Ia supernovae we find that the deceleration parameter, in addition to a small monopole, indeed has a much bigger dipole component aligned with the CMB dipole which falls exponentially with redshift $z$: $q_0 = q_\mathrm{m} + \vec{q}_\mathrm{d}.\hat{n}\exp(-z/S)$. The best fit to data yields $q_\mathrm{d} = -8.03$ and $S = 0.0262~(\Rightarrow d \sim 100~\mathrm{Mpc})$, rejecting isotropy ($q_\mathrm{d} = 0$) with $3.9\sigma$ statistical significance, while $q_\mathrm{m} = -0.157$ and consistent with no acceleration ($q_\mathrm{m} = 0$) at $1.4\sigma$. Thus the cosmic acceleration deduced from supernovae may be an artefact of our being non-Copernican observers, rather than evidence for a dominant component of `dark energy' in the Universe.

## Formulae for line bundle cohomology on Calabi‐Yau threefolds

Fortschritte der Physik / Progress of Physics Wiley (2019)

We present closed form expressions for the ranks of all cohomology groups of holomorphic line bundles on several Calabi‐Yau threefolds realised as complete intersections in products of projective spaces. The formulae have been obtained by systematising and extrapolating concrete calculations and they have been checked computationally. Although the intermediate calculations often involve laborious computations of ranks of Leray maps in the Koszul spectral sequence, the final results for cohomology follow a simple pattern. The space of line bundles can be divided into several different regions, and in each such region the ranks of all cohomology groups can be expressed as polynomials in the line bundle integers of degree at most three. The number of regions increases and case distinctions become more complicated for manifolds with a larger Picard number. We also find explicit cohomology formulae for several non‐simply connected Calabi‐Yau threefolds realised as quotients by freely acting discrete symmetries. More cases may be systematically handled by machine learning algorithms.

## Reconstructing the EFT of inflation from cosmological data

SciPost Physics SciPost **7** (2019) 49-

Reconstructions of the primordial power spectrum (PPS) of curvature perturbations from cosmic microwave background anisotropies and large-scale structure data suggest that the usually assumed power-law PPS has localised features (up to $\sim 10\%$ in amplitude), although of only marginal significance in the framework of $\Lambda$CDM cosmology. On the other hand if the underlying cosmology is assumed to be Einstein-de Sitter, larger features in the PPS (up to $\sim 20\%$) are required to accurately fit the observed acoustic peaks. Within the context of single clock inflation, we show that any given reconstruction of the PPS can be mapped on to functional parameters of the underlying effective theory of the adiabatic mode within a 2nd-order formalism, provided the best fit fractional change of the PPS, $\Delta\mathcal{P}_\mathcal{R}/\mathcal{P}_\mathcal{R}$ is such that $(\Delta\mathcal{P}_\mathcal{R}/\mathcal{P}_\mathcal{R})^3$ falls within the $1\,\sigma$ confidence interval of the reconstruction for features induced by variations of either the sound speed $c_\mathrm{s}$ or the slow-roll parameter $\epsilon$. Although there is a degeneracy amongst these functional parameters (and the models that project onto them), we can identify simple representative inflationary models that yield such features in the PPS. Thus we provide a dictionary (more accurately, a thesaurus) to go from observational data, via the reconstructed PPS, to models that reproduce them to per cent level precision.

## Cosmic ray spectrum and composition from PeV to EeV using 3 years of data from IceTop and IceCube

PHYSICAL REVIEW D **100** (2019) ARTN 082002

## Efficient propagation of systematic uncertainties from calibration to analysis with the SnowStorm method in IceCube

Journal of Cosmology and Astroparticle Physics IOP Publishing **2019** (2019) 048-048

## A response to Rubin & Heitlauf: "Is the expansion of the universe accelerating? All signs \emph{still} point to yes"

arXiv (2019)

We have shown (Colin et al. 2019) that the acceleration of the Hubble expansion rate inferred from Type Ia supernovae is essentially a dipole with 3.9$\sigma$ significance, approximately aligned with the CMB dipole, while its monopole component which may be interpreted as due to a Cosmological Constant (or more generally dark energy) is consistent with zero at 1.4$\sigma$. This is challenged by Rubin & Heitlauf (2019) who assert that we incorrectly assumed the supernova light-curve parameters to be independent of redshift, and erred further in considering their measured redshifts (in the heliocentric frame) rather than transforming them to the CMB frame (in which the universe supposedly looks isotropic). We emphasize that our procedure is justified and that their criticism serves only to highlight the rather "arbitrary corrections" that are made to the data in order to infer isotropic cosmic acceleration. This is a vivid illustration of the 'Cosmological Fitting Problem' faced by observers who live in an inhomogeneous universe but still use the maximally symmetric FLRW cosmolgy to interpret observations.

## Ad Lucem: QED parton distribution functions in the MMHT framework

EUROPEAN PHYSICAL JOURNAL C **79** (2019) ARTN 811

## The complex life of hydrodynamic modes

Journal of High Energy Physics Springer Science and Business Media LLC **2019** (2019) 97