Updated directions of IceCube HESE events with the latest ice model using DirectFit
Tianlu Yuan, Rasha Abbasi, M. Ackermann, Jenni Adams, Sanjib Kumar Agarwalla, Juanan Aguilar, M. Ahlers, Jean-Marco Alameddine, Najia Moureen Binte Amin, K. Andeen, G. Anton, C. Argüelles, Yosuke Ashida, Sofia Athanasiadou, Spencer Axani, X. Bai, Aswathi Balagopal, Moreno Baricevic, S. W. Barwick, Vedant Basu, Ryan Bay, J. J. Beatty, J. Becker Tjus, Jakob Beise, Chiara Bellenghi, Charlotte Benning, S. BenZvi, D. Berley, E. Bernardini, D. Besson, E. Blaufuss, Summer Blot, Federico Bontempo, Julia Book, Caterina Boscolo Meneguolo, Sebastian BOSER, O. Botner, J. Böttcher, Etienne Bourbeau, Jim Braun, Bennett Brinson, Jannes Brostean-Kaiser, Ryan T. Burley, Raffaela Busse, Delaney Butterfield, Michael Campana, Kiara Carloni, Erin Carnie-Bronca, Sharmistha Chattopadhyay, Thien Nhan Chau, Chujie Chen, Zheyang Chen, D. Chirkin, Seowon Choi, Brian Clark, Lew Classen, Alan Coleman, Gabriel Collin, A. Connolly, J. M. Conrad, Paul Coppin, Pablo Correa, D. F. Cowen, Pranav Dave, C. De Clercq, James DeLaunay, Diyaselis Delgado Lopez, Shuyang Deng, Kunal Deoskar, Abhishek Desai, P. Desiati, K. D. de Vries, G. de Wasseige, T. DeYoung, Alejandro Díaz, J. C. Díaz–Vélez, Markus Dittmer, Alba Domi, Hrvoje Dujmović, M. A. DuVernois, Thomas Ehrhardt, P. Eller, Enrico Ellinger, Sharif El Mentawi, Dominik Elsässer, Ralph Engel, Hannah Erpenbeck, John Evans, P. A. Evenson, Kwok Lung Fan, Ke Fang, Kareem Ramadan Farrag, A. R. Fazely, Anatoli Fedynitch, Nora Feigl, Sebastian Fiedlschuster, C. Finley, Leander Fischer, D. B. Fox, A. Franckowiak
Abstract
The initial evidence of astrophysical neutrinos by the IceCube Neutrino Observatory stemmed from the high-energy starting events (HESE) sample: a selection of the highest-energy neutrino interactions that occurred within the detector fiducial volume. Each event was reconstructed based on our best knowledge of the ice at the time, with the latest results published in a description of the sample using 7.5 years of data. Since then, several major improvements in ice modeling have occurred using in-situ calibration data. These include a microscopic description of ice anisotropy arising from ice crystal birefringence and a more complete mapping of the ice layer undulations across the detector. The improvements feed into more accurate descriptions of individual events, and can especially affect the directional reconstruction of particle showers. Here, we apply the latest ice model in an exact manner to reconstruct IceCube’s high-energy events using DirectFit. This reconstruction samples posterior distributions across parameters of interest by performing full event resimulation and photon propagation at each step. We obtain improved per-event descriptions, as well as updates on previously published source searches using the aggregated sample.