arXiv subjects

Philipp Eller

Publications and source records attributed to Philipp Eller.

22 records · Page 2Linked to original sources

arXiv2021

Search for high-energy neutrino sources from the direction of IceCube alert events

We use IceCube's high-statistics, neutrino-induced, through-going muon samples to search for astrophysical neutrino sources. Specifically, we analyze the arrival directions of IceCube's highest energy neutrinos. These high-energy events allow for a good angular reconstruction of their origin. Additionally, they have a high probability to come from an astrophysical source. On average, 8 neutrino events that satisfy these selection criteria are detected per year. Using these neutrino events as a source catalog, we present a search for the production sites of cosmic neutrinos. In this contribution we explore a time-dependent analysis, and present preliminary 3$σ$ discovery potential fluences of $\approx 2.7 \cdot 10^{-2} \rm{GeV}/\rm{cm}^2$. We construct the fluences using expectation maximization.

astro-ph.HE↗

arXiv2020

Parallelizing MCMC Sampling via Space Partitioning

Efficient sampling of many-dimensional and multimodal density functions is a task of great interest in many research fields. We describe an algorithm that allows parallelizing inherently serial Markov chain Monte Carlo (MCMC) sampling by partitioning the space of the function parameters into multiple subspaces and sampling each of them independently. The samples of the different subspaces are then reweighted by their integral values and stitched back together. This approach allows reducing sampling wall-clock time by parallel operation. It also improves sampling of multimodal target densities and results in less correlated samples. Finally, the approach yields an estimate of the integral of the target density function.

stat.CO↗

arXiv2020

Integration with an Adaptive Harmonic Mean Algorithm

Numerically estimating the integral of functions in high dimensional spaces is a non-trivial task. A oft-encountered example is the calculation of the marginal likelihood in Bayesian inference, in a context where a sampling algorithm such as a Markov Chain Monte Carlo provides samples of the function. We present an Adaptive Harmonic Mean Integration (AHMI) algorithm. Given samples drawn according to a probability distribution proportional to the function, the algorithm will estimate the integral of the function and the uncertainty of the estimate by applying a harmonic mean estimator to adaptively chosen regions of the parameter space. We describe the algorithm and its mathematical properties, and report the results using it on multiple test cases.

physics.data-an↗

arXiv2014

Measurement of VZ production cross sections in Z -> bb decay channels in pp collisions at 8 TeV

We present a measurement of the WZ and ZZ production cross sections in proton-proton collisions at 8 TeV in final states where one Z boson decays to b-tagged jets, while the other gauge boson, either W or Z, is detected through its leptonic decay. The results are based on data corresponding to an integrated luminosity of 18.9 /fb collected with the CMS detector at the Large Hadron Collider.

hep-ex↗