Prof Subir Sarkar: Publications

IceCube

IceCube at Oxford

I am a member since 2004 of the IceCube collaboration which discovered cosmic high energy neutrinos and identified some of their astrophysical sources.

IceCube @ Oxford

GollumFit: An IceCube Open-Source Framework for Binned-Likelihood Neutrino Telescope Analyses

Computer Physics Communications Elsevier (2026) 110195

Authors:

R Abbasi, M Ackermann, J Adams, SK Agarwalla, JA Aguilar, M Ahlers, JM Alameddine, NM Amin, K Andeen, C Argüelles, Y Ashida, S Athanasiadou, SN Axani, R Babu, X Bai, AV Balagopal, M Baricevic, SW Barwick, S Bash, V Basu, R Bay, JJ Beatty, J Becker Tjus, P Behrens, J Beise, C Bellenghi, B Benkel, S BenZvi, D Berley, E Bernardini, DZ Besson, E Blaufuss, L Bloom, S Blot, F Bontempo, JY Book Motzkin, C Boscolo Meneguolo, S Böser, O Botner, J Böttcher, J Braun, B Brinson, Z Brisson-Tsavoussis, RT Burley, D Butterfield, MA Campana, K Carloni, J Carpio, S Chattopadhyay, N Chau, Z Chen, D Chirkin, BA Clark, A Coleman, P Coleman, GH Collin, A Connolly, JM Conrad, R Corley, DF Cowen, C De Clercq, JJ DeLaunay, D Delgado, T Delmeulle, S Deng, A Desai, P Desiati, KD de Vries, G de Wasseige, T DeYoung, JC Díaz-Vélez, A Diaz, S DiKerby, M Dittmer, A Domi, L Draper, L Dueser, H Dujmovic, D Durnford, K Dutta, MA DuVernois, T Ehrhardt, L Eidenschink, A Eimer, P Eller, E Ellinger, D Elsässer, R Engel, H Erpenbeck, W Esmail, J Evans, PA Evenson, KL Fan, K Fang, K Farrag, AR Fazely, A Fedynitch, N Feigl, C Finley, L Fischer, D Fox, A Franckowiak, S Fukami, P Fürst, J Gallagher, E Ganster, A Garcia, M Garcia, G Garg, E Genton, L Gerhardt, A Ghadimi, C Glaser, T Glüsenkamp, JG Gonzalez, S Goswami, A Granados, D Grant, SJ Gray, S Griffin, S Griswold, KM Groth, D Guevel, C Günther, P Gutjahr, C Ha, C Haack, A Hallgren, L Halve, F Halzen, L Hamacher, M Ha Minh, M Handt, K Hanson, J Hardin, AA Harnisch, P Hatch, A Haungs, J Häußler, K Helbing, J Hellrung, L Hennig, L Heuermann, R Hewett, N Heyer, S Hickford, A Hidvegi, C Hill, GC Hill, R Hmaid, KD Hoffman, S Hori, K Hoshina, M Hostert, W Hou, T Huber, K Hultqvist, R Hussain, K Hymon, A Ishihara, W Iwakiri, M Jacquart, S Jain, O Janik, M Jeong, M Jin, BJP Jones, N Kamp, D Kang, X Kang, A Kappes, L Kardum, T Karg, M Karl, A Karle, A Katil, M Kauer, JL Kelley, M Khanal, A Khatee Zathul, A Kheirandish, H Kimku, J Kiryluk, C Klein, SR Klein, Y Kobayashi, A Kochocki, R Koirala, H Kolanoski, T Kontrimas, L Köpke, C Kopper, DJ Koskinen, P Koundal, M Kowalski, T Kozynets, N Krieger, J Krishnamoorthi, T Krishnan, K Kruiswijk, E Krupczak, A Kumar, E Kun, N Kurahashi, N Lad, C Lagunas Gualda, L Lallement Arnaud, M Lamoureux, MJ Larson, F Lauber, JP Lazar, K Leonard Deholtona, A Leszczyńska, J Liao, YT Liu, M Liubarska, C Love, L Lu, F Lucarelli, W Luszczak, Y Lyu, J Madsen, E Magnus, KBM Mahn, Y Makino, E Manao, S Mancina, A Mand, W Marie Sainte, IC Mariş, S Marka, Z Marka, L Marten, I Martinez-Soler, R Maruyama, F Mayhew, F McNally, JV Mead, K Meagher, S Mechbal, A Medina, M Meier, Y Merckx, L Merten, J Mitchell, L Molchany, T Montaruli, RW Moore, Y Morii, R Morse, A Mosbrugger, M Moulai, D Mousadi, T Mukherjee, R Naab, M Nakos, U Naumann, J Necker, L Neste, M Neumann, H Niederhausen, MU Nisa, K Noda, A Noell, A Novikov, A Obertacke Pollmann, V O’Dell, A Olivas, R Orsoe, J Osborn, E O’Sullivan, V Palusova, H Pandya, A Parenti, N Park, V Parrish, EN Paudel, L Paul, C Pérez de los Heros, T Pernice, J Peterson, A Pizzuto, M Plum, A Pontén, V Poojyam, Y Popovych, M Prado Rodriguez, B Pries, R Procter-Murphy, GT Przybylski, L Pyras, C Raab, J Rack-Helleis, N Rad, M Ravn, K Rawlins, Z Rechav, A Rehman, I Reistroffer, E Resconi, S Reusch, CD Rho, W Rhode, B Riedel, A Rifaie, EJ Roberts, S Robertson, M Rongen, A Rosted, C Rott, T Ruhe, L Ruohan, I Safa, J Saffer, D Salazar-Gallegos, P Sampathkumar, A Sandrock, G Sanger-Johnson, M Santander, S Sarkar, J Savelberg, P Savina, P Schaile, M Schaufel, H Schieler, S Schindler, L Schlickmann, A Schneider, B Schlüter, F Schlüter, N Schmeisser, T Schmidt, FG Schröder, L Schumacher, S Schwirn, S Sclafani, D Seckel, L Seen, M Seikh, S Seunarine, PA Sevle Myhr, R Shah, S Shefali, N Shimizu, M Silva, B Skrzypek, R Snihur, J Soedingrekso, A Søgaard, D Soldin, P Soldin, G Sommani, C Spannfellner, GM Spiczak, C Spiering, J Stachurska, M Stamatikos, T Stanev, T Stezelberger, T Stürwald, T Stuttard, GW Sullivan, I Taboada, S Ter-Antonyan, A Terliuk, A Thakuri, M Thiesmeyer, WG Thompson, J Thwaites, S Tilav, K Tollefson, S Toscano, D Tosi, A Trettin, MA Unland Elorrieta, AK Upadhyay, K Upshaw, A Vaidyanathan, N Valtonen-Mattila, J Vandenbroucke, T Van Eeden, N van Eijndhoven, J van Santen, J Vara, F Varsi, J Veitch-Michaelis, M Venugopal, M Vereecken, S Vergara Carrasco, S Verpoest, D Veske, A Vijai, J Villarreal, C Walck, N Wandkowsky, A Wang, E Warrick, C Weaver, P Weigel, A Weindl, AY Wen, C Wendt, J Werthebach, M Weyrauch, N Whitehorn, CH Wiebusch, DR Williams, L Witthaus, M Wolf, G Wrede, XW Xu, JP Yanez, E Yildizci, S Yoshida, R Young, F Yu, S Yu, T Yuan, A Zegarelli, S Zhang, Z Zhang, P Zhelnin, P Zilberman, M Zimmerman

Abstract:

We present GollumFit, a framework designed for performing binned-likelihood analyses on neutrino telescope data. GollumFit incorporates model parameters common to any neutrino telescope and also model parameters specific to the IceCube Neutrino Observatory. We provide a high-level overview of its key features and how the code is organized. We then discuss the performance of the fitting in a typical analysis scenario, highlighting the ability to fit over tens of nuisance parameters. We present some examples showing how to use the package for likelihood minimization tasks. This framework uniquely incorporates the particular model parameters necessary for neutrino telescopes, and solves an associated likelihood problem in a time-efficient manner. PROGRAM Program title: GollumFit Documentation website: https://docs.icecube.aq/gollumfit/main/index.html Developer's repository link: https://github.com/icecube/GollumFit Licensing provisions: GNU Lesser General Public License 2.1 (LGPL) Programming language: C++, Python Nature of problem: Statistical analysis of data from neutrino telescope experiments is often complex and computationally demanding, owing to the need to optimize a likelihood function over many parameters that describe sources of systematic uncertainties and quantities of interest. Solution method: We introduce a framework that performs binned-likelihood optimization, whose performance can handle the number of parameters typical for a neutrino telescope analysis. We highlight a method to perform event-by-event reweighting to incorporate the experimental parameters. In particular, for neutrino telescopes the parameters that incorporate the uncertainties in the atmospheric neutrino flux are common across all experiments and analyses, and are implemented in our framework. The framework has been designed to be easily extendable in the number of observable dimensions and fit parameters. Finally, we use an automatic differentiation package to achieve computational speed in the likelihood optimization.

Neural posterior estimation of the neutrino direction in IceCube using transformer-encoded normalizing flows on the sphere

(2026)

Authors:

R Abbasi, M Ackermann, J Adams, JA Aguilar, M Ahlers, JM Alameddine, S Ali, NM Amin, K Andeen, C Argüelles, Y Ashida, S Athanasiadou, SN Axani, R Babu, X Bai, A Balagopal V., SW Barwick, V Basu, R Bay, JJ Beatty, J Becker Tjus, P Behrens, J Beise, C Bellenghi, S Benkel, S BenZvi, D Berley, E Bernardini, DZ Besson, E Blaufuss, L Bloom, S Blot, F Bontempo, JY Book Motzkin, C Boscolo Meneguolo, S Böser, O Botner, J Böttcher, J Braun, B Brinson, Z Brisson-Tsavoussis, RT Burley, D Butterfield, K Carloni, J Carpio, N Chau, Z Chen, D Chirkin, S Choi, A Chubarov, BA Clark, GH Collin, DA Coloma Borja, A Connolly, JM Conrad, DF Cowen, C De Clercq, JJ DeLaunay, D Delgado, T Delmeulle, S Deng, P Desiati, KD de Vries, G de Wasseige, T DeYoung, JC Díaz-Vélez, S DiKerby, T Ding, M Dittmer, A Domi, L Draper, L Dueser, D Durnford, K Dutta, MA DuVernois, T Ehrhardt, L Eidenschink, A Eimer, C Eldridge, P Eller, E Ellinger, D Elsässer, R Engel, H Erpenbeck, W Esmail, S Eulig, J Evans, PA Evenson, KL Fan, K Fang, K Farrag, AR Fazely, A Fedynitch, N Feigl, C Finley, D Fox, A Franckowiak, S Fukami, P Fürst, J Gallagher, E Ganster, A Garcia, M Garcia, E Genton, L Gerhardt, A Ghadimi, C Glaser, T Glüsenkamp, JG Gonzalez, S Goswami, A Granados, D Grant, SJ Gray, S Griffin, KM Groth, D Guevel, C Günther, P Gutjahr, C Ha, A Hallgren, L Halve, F Halzen, L Hamacher, M Handt, K Hanson, J Hardin, AA Harnisch, P Hatch, A Haungs, J Häußler, K Helbing, J Hellrung, B Henke, L Hennig, F Henningsen, L Heuermann, R Hewett, N Heyer, S Hickford, A Hidvegi, C Hill, GC Hill, R Hmaid, KD Hoffman, A Hollnagel, D Hooper, S Hori, K Hoshina, M Hostert, W Hou, M Hrywniak, T Huber, K Hultqvist, K Hymon, A Ishihara, W Iwakiri, M Jacquart, S Jain, O Janik, M Jansson, M Jin, N Kamp, D Kang, W Kang, A Kappes, L Kardum, T Karg, A Karle, A Katil, M Kauer, JL Kelley, M Khanal, A Khatee Zathul, A Kheirandish, T Kim, H Kimku, F Kirchner, J Kiryluk, C Klein, SR Klein, Y Kobayashi, S Koch, A Kochocki, R Koirala, H Kolanoski, T Kontrimas, L Köpke, C Kopper, DJ Koskinen, P Koundal, M Kowalski, T Kozynets, A Kravka, N Krieger, T Krishnan, K Kruiswijk, E Krupczak, A Kumar, E Kun, N Kurahashi, C Lagunas Gualda, L Lallement Arnaud, MJ Larson, F Lauber, JP Lazar, K Leonard DeHolton, A Leszczyńska, C Li, J Liao, C Lin, QR Liu, YT Liu, M Liubarska, C Love, L Lu, F Lucarelli, W Luszczak, Y Lyu, M Macdonald, E Magnus, Y Makino, E Manao, S Mancina, A Mand, IC Mariş, S Marka, Z Marka, L Marten, I Martinez-Soler, R Maruyama, J Mauro, F Mayhew, F McNally, K Meagher, A Medina, M Meier, Y Merckx, L Merten, J Mitchell, L Molchany, S Mondal, T Montaruli, RW Moore, Y Morii, A Mosbrugger, D Mousadi, E Moyaux, T Mukherjee, M Nakos, U Naumann, J Necker, L Neste, M Neumann, H Niederhausen, MU Nisa, K Noda, A Noell, A Novikov, A Obertacke, V O'Dell, A Olivas, R Orsoe, J Osborn, E O'Sullivan, B Owens, V Palusova, H Pandya, A Parenti, N Park, V Parrish, EN Paudel, L Paul, C Pérez de los Heros, T Pernice, TC Petersen, J Peterson, S Pick, M Plum, A Pontén, V Poojyam, B Pries, R Procter-Murphy, GT Przybylski, L Pyras, C Raab, J Rack-Helleis, N Rad, M Ravn, K Rawlins, Z Rechav, A Rehman, I Reistroffer, E Resconi, S Reusch, CD Rho, W Rhode, L Ricca, B Riedel, A Rifaie, EJ Roberts, S Rodan, M Rongen, A Rosted, C Rott, T Ruhe, L Ruohan, D Ryckbosch, J Saffer, D Salazar-Gallegos, P Sampathkumar, A Sandrock, G Sanger-Johnson, M Santander, S Sarkar, M Scarnera, M Schaufel, H Schieler, S Schindler, L Schlickmann, B Schlüter, F Schlüter, N Schmeisser, T Schmidt, A Scholz, FG Schröder, S Schwirn, S Sclafani, D Seckel, L Seen, M Seikh, S Seunarine, PA Sevle Myhr, R Shah, S Shah, S Shefali, N Shimizu, B Skrzypek, R Snihur, J Soedingrekso, D Soldin, P Soldin, G Sommani, C Spannfellner, GM Spiczak, C Spiering, J Stachurska, M Stamatikos, T Stanev, T Stezelberger, T Stürwald, T Stuttard, GW Sullivan, I Taboada, S Ter-Antonyan, A Terliuk, A Thakuri, M Thiesmeyer, WG Thompson, J Thwaites, S Tilav, K Tollefson, JA Torres, S Toscano, D Tosi, K Upshaw, A Vaidyanathan, N Valtonen-Mattila, J Valverde, J Vandenbroucke, T Van Eeden, N van Eijndhoven, L Van Rootselaar, J van Santen, J Vara, F Varsi, M Venugopal, M Vereecken, S Vergara Carrasco, S Verpoest, D Veske, A Vijai, J Villarreal, C Walck, A Wang, EHS Warrick, C Weaver, P Weigel, A Weindl, J Weldert, AY Wen, C Wendt, J Werthebach, M Weyrauch, N Whitehorn, CH Wiebusch, DR Williams, L Witthaus, G Wrede, XW Xu, JP Yanez, Y Yao, E Yildizci, S Yoshida, R Young, F Yu, S Yu, T Yuan, S Yun-Cárcamo, A Zander Jurowitzki, A Zegarelli, S Zhang, Z Zhang, P Zhelnin, P Zilberman

Chasing Gamma-Ray Signals from Binary Neutron Star Coalescences with the Cherenkov Telescope Array: Prospects and Observing Strategies

(2026)

Authors:

S Abe, J Abhir, A Abhishek, F Acero, A Acharyya, R Adam, A Aguasca-Cabot, I Agudo, I Albanese, J Alfaro, C Alispach, R Alves Batista, E Amato, G Ambrosi, D Ambrosino, F Ambrosino, L Angel, C Aramo, A Arbet-Engels, C Arcaro, C Arena, TTH Arnesen, K Asano, H Ashkar, C Bakshi, C Balazs, M Balbo, A Baquero Larriva, V Barbosa Martins, JA Barrio, C Bartolini, I Batkovic, R Batzofin, N Bavdaz, J Becerra Gonzalez, G Beck, W Benbow, E Bernardini, MG Bernardini, J Bernete, A Berti, B Bertucci, V Beshley, P Bhattacharjee, S Bhattacharyya, C Bigongiari, A Biland, E Bissaldi, M Bla na, O Blanch, J Blazek, C Boisson, G Bonnoli, Z Bosnjak, E Bottacini, M Bottcher, E Bronzini, G Brunelli, J Buces Saez, A Bulgarelli, T Bulik, L Burmistrov, PG Calisse, A Campoy-Ordaz, BK Cantlay, G Capasso, A Caproni, R Capuzzo-Dolcetta, M Cardillo, S Caroff, A Carosi, E Carquin, S Casanova, E Cascone, F Cassol, G Castignani, F Catalani, D Cerasole, M Cerruti, PM Chadwick, S Chaty, AW Chen, Y Chen, M Chernyakova, A Chiavassa, G Chon, J Chudoba, L Chytka, GM Cicciari, A Cifuentes Santos, CH Coimbra Araujo, JL Contreras, B Cornejo, J Cortina, A Costa, G Cotter, P Cristofari, O Cuevas, Z Curtis-Ginsberg, G D'Amico, F D'Ammando, P D'Avanzo, P Da Vela, L David, F Dazzi, M de Bony de Lavergne, V De Caprio, EM de Gouveia Dal Pino, B De Lotto, M de Naurois, V de Souza, L del Peral, MV del Valle, C Delgado, D della Volpe, D Depaoli, A Dettlaff, L Di Bella, T Di Girolamo, A Di Piano, F Di Pierro, R Di Tria, L Di Venere, R Dima, A Dinesh, E Do Souto Espiñeira, D Dominis Prester, A Donini, D Dorner, J Dorner, M Doro, L Ducci, VV Dwarkadas, J Ebr, C Eckner, K Egberts, L Eisenberger, D Elsasser, G Emery, C Escanuela Nieves, P Escarate, M Escobar Godoy, J Escudero Pedrosa, P Esposito, D Falceta-Goncalves, E Fedorova, S Fegan, K Feijen, Q Feng, G Ferrand, E Fiandrini, A Fiasson, M Filipovic, V Fioretti, L Foffano, G Fontaine, Y Fukazawa, Y Fukui, G Galanti, G Galaz, S Gallozzi, V Gammaldi, M Garczarczyk, C Gasbarra, D Gasparrini, M Gaug, G Ghirlanda, JG Giesbrecht Formiga Paiva, N Giglietto, F Giordano, M Giroletti, R Giuffrida, J-F Glicenstein, P Goldoni, JM Gonzalez, J Goulart Coelho, T Gradetzke, J Granot, R Grau, D Green, JG Green, J Grube, J Hackfeld, D Hadasch, A Hahn, P Hamal, W Hanlon, S Hara, VM Harvey, T Hassan, K Hayashi, L Heckmann, N Hiroshima, B Hnatyk, R Hnatyk, D Horan, P Horvath, D Hrupec, S Hussain, M Iarlori, T Inada, F Incardona, S Inoue, F Iocco, A Iuliano, Jahanvi, M Jamrozy, P Janecek, F Jankowsky, C Jarnot, I Jaroschewski, P Jean, V Jilek, J Jimenez Quiles, W Jin, E Joshi, J Jurysek, V Karas, H Katagiri, J Kataoka, S Kaufmann, T Keita, D Kerszberg, M Kherlakian, DB Kieda, R Kissmann, T Kleiner, Y Kobayashi, K Kohri, D Kolar, N Komin, A Kong, K Kosack, D Kostunin, G Kowal, H Kubo, J Kushida, A La Barbera, N La Palombara, B Lacave, M Lainez, A Lamastra, J Lapington, S Lazarevic, J-P Lenain, F Leone, E Leonora, G Leto, E Lindfors, S Lombardi, F Longo, R Lopez-Coto, M Lopez-Moya, A Lopez-Oramas, J Lozano Bahilo, PL Luque-Escamilla, E Lyard, O Macias, P Majumdar, M Makariev, D Mandat, S Mangano, A Marchetti, M Mariotti, S Markoff, I Marquez, G Marsella, O Martinez, G Maurin, D Mazin, D Melkumyan, S Menon, E Mestre, DM-A Meyer, D Miceli, M Miceli, M Michailidis, T Miener, JM Miranda, R Moderski, M Molero, C Molfese, E Molina, K Morik, A Morselli, E Moulin, AL Muller, K Munari, T Murach, A Muraczewski, H Muraishi, T Nakamori, R Nemmen, J Niemiec, D Nieto, M Nievas Rosillo, L Nikolic, K Noda, D Nosek, V Novotny, S Nozaki, A Okumura, RA Ong, R Orito, M Orlandini, E Orlando, S Orlando, J Otero-Santos, I Oya, M Ozlati Moghadam, A Pagliaro, M Palatiello, A Pandey, G Panebianco, D Paneque, FR Pantaleo, JM Paredes, B Patricelli, A Pe'er, M Pech, M Pecimotika, M Peresano, E Peretti, J Perez-Romero, G Peron, F Perrotta, M Persic, O Petruk, F Pfeifle, E Pietropaolo, M Pihet, L Pinchbeck, F Pintore, G Pirola, C Pittori, F Podobnik, M Pohl, V Pollet, G Ponti, E Prandini, G Principe, M Prouza, E Pueschel, G Puhlhofer, ML Pumo, M Punch, A Quirrenbach, S Raino, R Rando, S Recchia, A Reimer, O Reimer, I Reis, A Reisenegger, W Rhode, M Ribo, C Ricci, T Richtler, J Rico, L Riitano, V Rizi, E Roache, G Rodriguez Fernandez, P Romano, G Romeo, J Rosado, A Rosales de Leon, A Roy, I Sadeh, L Saha, T Saito, M Sanchez-Conde, P Sangiorgi, H Sano, R Santos-Lima, V Sapienza, S Sarkar, FG Saturni, A Scherer, F Schiavone, P Schipani, P Schovanek, F Schussler, O Sergijenko, H Siejkowski, A Simongini, V Sliusar, A Slowikowska, I Sofia, H Sol, S Spinello, A Stamerra, T Starecki, R Starling, T Stolarczyk, Y Suda, A Sunny, T Suomijarvi, R Takeishi, SJ Tanaka, F Tavecchio, T Tavernier, Y Terada, M Teshima, V Testa, WW Tian, Y Tian, L Tibaldo, O Tibolla, SJ Tingay, CJ Todero Peixoto, F Tombesi, D Tonev, F Torradeflot, DF Torres, N Tothill, G Tovmassian, G Tripodo, A Trois, A Tsiahina, A Tutone, L Vaclavek, M Vacula, C van Eldik, J Vandenbroucke, V Vassiliev, M Vazquez Acosta, M Vecchi, S Vercellone, SD Vergani, I Viale, A Viana, A Vigliano, J Vignatti, CF Vigorito, J Villanueva, E Visentin, V Voitsekhovskyi, S Vorobiov, I Vovk, T Vuillaume, R Walter, M Wechakama, M White, A Wierzcholska, M Will, F Wohlleben, A Wolter, F Xotta, T Yamamoto, R Yamazaki, T Yoshikoshi, M Zacharias, G Zaharijas, R Zanmar Sanchez, D Zavrtanik, M Zavrtanik, A Zech, VI Zhdanov, J Zuriaga-Puig

Physics potential of the IceCube Upgrade for atmospheric neutrino oscillations

Physical Review D American Physical Society (APS) 113:7 (2026) 072009

Authors:

R Abbasi, M Ackermann, J Adams, SK Agarwalla, JA Aguilar, M Ahlers, JM Alameddine, S Ali, NM Amin, K Andeen, C Argüelles, Y Ashida, S Athanasiadou, SN Axani, R Babu, X Bai, J Baines-Holmes, A Balagopal V., SW Barwick, S Bash, V Basu, R Bay, JJ Beatty, J Becker Tjus, P Behrens, J Beise, C Bellenghi, B Benkel, S BenZvi, D Berley, E Bernardini, DZ Besson, E Blaufuss, L Bloom, S Blot, I Bodo, F Bontempo, JY Book Motzkin, C Boscolo Meneguolo, S Böser, O Botner, J Böttcher, J Braun, B Brinson, Z Brisson-Tsavoussis, RT Burley, D Butterfield, MA Campana, K Carloni, J Carpio, S Chattopadhyay, N Chau, Z Chen, D Chirkin, S Choi, BA Clark, A Coleman, P Coleman, GH Collin, DA Coloma Borja, A Connolly, JM Conrad, R Corley, DF Cowen, C De Clercq, JJ DeLaunay, D Delgado, T Delmeulle, S Deng, P Desiati, KD de Vries, G de Wasseige, T DeYoung, JC Díaz-Vélez, S DiKerby, M Dittmer, A Domi, L Draper, L Dueser, D Durnford, K Dutta, MA DuVernois, T Ehrhardt, L Eidenschink, A Eimer, P Eller, E Ellinger, D Elsässer, R Engel, H Erpenbeck, W Esmail, S Eulig, J Evans, PA Evenson, KL Fan, K Fang, K Farrag, AR Fazely, A Fedynitch, N Feigl, C Finley, L Fischer, D Fox, A Franckowiak, S Fukami, P Fürst, J Gallagher, E Ganster, A Garcia, M Garcia, G Garg, E Genton, L Gerhardt, A Ghadimi, C Glaser, T Glüsenkamp, JG Gonzalez, S Goswami, A Granados, D Grant, SJ Gray, S Griffin, S Griswold, KM Groth, D Guevel, C Günther, P Gutjahr, C Ha, C Haack, A Hallgren, L Halve, F Halzen, L Hamacher, M Ha Minh, M Handt, K Hanson, J Hardin, AA Harnisch, P Hatch, A Haungs, J Häußler, K Helbing, J Hellrung, B Henke, L Hennig, F Henningsen, L Heuermann, R Hewett, N Heyer, S Hickford, A Hidvegi, C Hill, GC Hill, R Hmaid, KD Hoffman, D Hooper, S Hori, K Hoshina, M Hostert, W Hou, T Huber, K Hultqvist, K Hymon, A Ishihara, W Iwakiri, M Jacquart, S Jain, O Janik, M Jansson, M Jeong, M Jin, N Kamp, D Kang, W Kang, X Kang, A Kappes, L Kardum, T Karg, M Karl, A Karle, A Katil, T Katori, M Kauer, JL Kelley, M Khanal, A Khatee Zathul, A Kheirandish, H Kimku, J Kiryluk, C Klein, SR Klein, Y Kobayashi, A Kochocki, R Koirala, H Kolanoski, T Kontrimas, L Köpke, C Kopper, DJ Koskinen, P Koundal, M Kowalski, T Kozynets, N Krieger, J Krishnamoorthi, T Krishnan, K Kruiswijk, E Krupczak, A Kumar, E Kun, N Kurahashi, N Lad, C Lagunas Gualda, L Lallement Arnaud, M Lamoureux, MJ Larson, F Lauber, JP Lazar, K Leonard DeHolton, A Leszczyńska, J Liao, C Lin, YT Liu, M Liubarska, C Love, L Lu, F Lucarelli, W Luszczak, Y Lyu, J Madsen, E Magnus, Y Makino, E Manao, S Mancina, A Mand, IC Mariş, S Marka, Z Marka, L Marten, I Martinez-Soler, R Maruyama, J Mauro, F Mayhew, F McNally, JV Mead, K Meagher, S Mechbal, A Medina, M Meier, Y Merckx, L Merten, A Millsop, J Mitchell, L Molchany, T Montaruli, RW Moore, Y Morii, A Mosbrugger, M Moulai, D Mousadi, E Moyaux, T Mukherjee, R Naab, M Nakos, U Naumann, J Necker, L Neste, M Neumann, H Niederhausen, MU Nisa, K Noda, A Noell, A Novikov, A Obertacke Pollmann, V O’Dell, A Olivas, R Orsoe, J Osborn, E O’Sullivan, V Palusova, H Pandya, A Parenti, N Park, V Parrish, EN Paudel, L Paul, C Pérez de los Heros, T Pernice, J Peterson, M Plum, A Pontén, V Poojyam, Y Popovych, J Prado González, M Prado Rodriguez, B Pries, R Procter-Murphy, GT Przybylski, L Pyras, C Raab, J Rack-Helleis, N Rad, M Ravn, K Rawlins, Z Rechav, A Rehman, I Reistroffer, E Resconi, S Reusch, CD Rho, W Rhode, L Ricca, B Riedel, A Rifaie, EJ Roberts, S Robertson, M Rongen, A Rosted, C Rott, T Ruhe, L Ruohan, D Ryckbosch, J Saffer, D Salazar-Gallegos, P Sampathkumar, A Sandrock, G Sanger-Johnson, M Santander, S Sarkar, J Savelberg, M Scarnera, P Schaile, M Schaufel, H Schieler, S Schindler, L Schlickmann, B Schlüter, F Schlüter, N Schmeisser, T Schmidt, FG Schröder, L Schumacher, S Schwirn, S Sclafani, D Seckel, L Seen, M Seikh, S Seunarine, PA Sevle Myhr, R Shah, S Shefali, N Shimizu, B Skrzypek, R Snihur, J Soedingrekso, A Søgaard, D Soldin, P Soldin, G Sommani, C Spannfellner, GM Spiczak, C Spiering, J Stachurska, M Stamatikos, T Stanev, T Stezelberger, T Stürwald, T Stuttard, GW Sullivan, I Taboada, S Ter-Antonyan, A Terliuk, A Thakuri, M Thiesmeyer, WG Thompson, J Thwaites, S Tilav, K Tollefson, S Toscano, D Tosi, A Trettin, AK Upadhyay, K Upshaw, A Vaidyanathan, N Valtonen-Mattila, J Valverde, J Vandenbroucke, T Van Eeden, N van Eijndhoven, L Van Rootselaar, J van Santen, J Vara, F Varsi, M Venugopal, M Vereecken, S Vergara Carrasco, S Verpoest, D Veske, A Vijai, J Villarreal, C Walck, A Wang, EHS Warrick, C Weaver, P Weigel, A Weindl, J Weldert, AY Wen, C Wendt, J Werthebach, M Weyrauch, N Whitehorn, CH Wiebusch, DR Williams, L Witthaus, M Wolf, G Wrede, XW Xu, JP Yanez, Y Yao, E Yildizci, S Yoshida, R Young, F Yu, S Yu, T Yuan, A Zegarelli, S Zhang, Z Zhang, P Zhelnin, P Zilberman

Abstract:

The IceCube Upgrade is an extension of the existing IceCube Neutrino Observatory and will be deployed in the 2025–2026 austral summer. It will significantly improve the sensitivity of the detector to atmospheric neutrino oscillations. The existing 86-string IceCube array contains a dense in-fill known as DeepCore which is optimized to measure neutrinos with energies down to a few GeV. The IceCube Upgrade will consist of seven new densely instrumented strings placed within the DeepCore volume to further enhance the performance in the GeV energy range. The additional strings will feature new optical modules, each containing multiple photomultiplier tubes (PMTs), in contrast to the existing modules that each contain a single PMT. This will more than triple the number of PMT channels with respect to the current IceCube configuration, allowing for improved detection efficiency and reconstruction performance at GeV energies. We describe necessary updates to simulation, event selection, and reconstruction to accommodate the higher data rates observed by the upgraded detector and the addition of multi-PMT modules. We determine the expected sensitivity of the IceCube Upgrade to the atmospheric neutrino oscillation parameters

\sin^{2} θ_{23}

and

Δ m_{32}^{2}

, the appearance of tau neutrinos and the neutrino mass ordering. The IceCube Upgrade will provide neutrino oscillation measurements that are of similar precision to those from accelerator experiments, while providing complementarity by probing higher energies and longer baselines, and with different sources of systematic uncertainties.

Evidence for a Spectral Break or Curvature in the Spectrum of Astrophysical Neutrinos from 5 TeV to 10 PeV

Physical Review Letters American Physical Society (APS) 136:12 (2026) 121002

Authors:

R Abbasi, M Ackermann, J Adams, SK Agarwalla, JA Aguilar, M Ahlers, JM Alameddine, S Ali, NM Amin, K Andeen, C Arguelles, Y Ashida, S Athanasiadou, SN Axani, R Babu, X Bai, J Baines-Holmes, A Balagopal V., SW Barwick, S Bash, V Basu, R Bay, JJ Beatty, J Becker Tjus, P Behrens, J Beise, C Bellenghi, B Benkel, S BenZvi, D Berley, E Bernardini, DZ Besson, E Blaufuss, L Bloom, S Blot, I Bodo, F Bontempo, JY Book Motzkin, C Boscolo Meneguolo, S Boser, O Botner, J Bottcher, J Braun, B Brinson, Z Brisson-Tsavoussis, RT Burley, D Butterfield, MA Campana, K Carloni, J Carpio, S Chattopadhyay, N Chau, Z Chen, D Chirkin, S Choi, BA Clark, A Coleman, P Coleman, GH Collin, DA Coloma Borja, A Connolly, JM Conrad, R Corley, DF Cowen, C De Clercq, JJ DeLaunay, D Delgado, T Delmeulle, S Deng, P Desiati, KD de Vries, G de Wasseige, T DeYoung, JC Diaz-Velez, S DiKerby, M Dittmer, A Domi, L Draper, L Dueser, D Durnford, K Dutta, MA DuVernois, T Ehrhardt, L Eidenschink, A Eimer, P Eller, E Ellinger, D Elsasser, R Engel, H Erpenbeck, W Esmail, S Eulig, J Evans, PA Evenson, KL Fan, K Fang, K Farrag, AR Fazely, A Fedynitch, N Feigl, C Finley, L Fischer, D Fox, A Franckowiak, S Fukami, P Furst, J Gallagher, E Ganster, A Garcia, M Garcia, G Garg, E Genton, L Gerhardt, A Ghadimi, C Glaser, T Glusenkamp, JG Gonzalez, S Goswami, A Granados, D Grant, SJ Gray, S Griffin, S Griswold, KM Groth, D Guevel, C Gunther, P Gutjahr, C Ha, C Haack, A Hallgren, L Halve, F Halzen, L Hamacher, M Ha Minh, M Handt, K Hanson, J Hardin, AA Harnisch, P Hatch, A Haungs, J Haussler, K Helbing, J Hellrung, B Henke, L Hennig, F Henningsen, L Heuermann, R Hewett, N Heyer, S Hickford, A Hidvegi, C Hill, GC Hill, R Hmaid, KD Hoffman, D Hooper, S Hori, K Hoshina, M Hostert, W Hou, T Huber, K Hultqvist, K Hymon, A Ishihara, W Iwakiri, M Jacquart, S Jain, O Janik, M Jansson, M Jeong, M Jin, N Kamp, D Kang, W Kang, X Kang, A Kappes, L Kardum, T Karg, M Karl, A Karle, A Katil, M Kauer, JL Kelley, M Khanal, A Khatee Zathul, A Kheirandish, H Kimku, J Kiryluk, C Klein, SR Klein, Y Kobayashi, A Kochocki, R Koirala, H Kolanoski, T Kontrimas, L Kopke, C Kopper, DJ Koskinen, P Koundal, M Kowalski, T Kozynets, N Krieger, J Krishnamoorthi, T Krishnan, K Kruiswijk, E Krupczak, A Kumar, E Kun, N Kurahashi, N Lad, C Lagunas Gualda, L Lallement Arnaud, M Lamoureux, MJ Larson, F Lauber, JP Lazar, K Leonard DeHolton, A Leszczynska, J Liao, C Lin, YT Liu, M Liubarska, C Love, L Lu, F Lucarelli, W Luszczak, Y Lyu, J Madsen, E Magnus, Y Makino, E Manao, S Mancina, A Mand, IC Maris, S Marka, Z Marka, L Marten, I Martinez-Soler, R Maruyama, J Mauro, F Mayhew, F McNally, JV Mead, K Meagher, S Mechbal, A Medina, M Meier, Y Merckx, L Merten, J Mitchell, L Molchany, T Montaruli, RW Moore, Y Morii, A Mosbrugger, M Moulai, D Mousadi, E Moyaux, T Mukherjee, R Naab, M Nakos, U Naumann, J Necker, L Neste, M Neumann, H Niederhausen, MU Nisa, K Noda, A Noell, A Novikov, A Obertacke Pollmann, V O’Dell, A Olivas, R Orsoe, J Osborn, E O’Sullivan, V Palusova, H Pandya, A Parenti, N Park, V Parrish, EN Paudel, L Paul, C Perez de los Heros, T Pernice, J Peterson, M Plum, A Ponten, V Poojyam, Y Popovych, M Prado Rodriguez, B Pries, R Procter-Murphy, GT Przybylski, L Pyras, C Raab, J Rack-Helleis, N Rad, M Ravn, K Rawlins, Z Rechav, A Rehman, I Reistroffer, E Resconi, S Reusch, CD Rho, W Rhode, L Ricca, B Riedel, A Rifaie, EJ Roberts, S Robertson, M Rongen, A Rosted, C Rott, T Ruhe, L Ruohan, D Ryckbosch, J Saffer, D Salazar-Gallegos, P Sampathkumar, A Sandrock, G Sanger-Johnson, M Santander, S Sarkar, J Savelberg, M Scarnera, P Schaile, M Schaufel, H Schieler, S Schindler, L Schlickmann, B Schluter, F Schluter, N Schmeisser, T Schmidt, FG Schroder, L Schumacher, S Schwirn, S Sclafani, D Seckel, L Seen, M Seikh, S Seunarine, PA Sevle Myhr, R Shah, S Shefali, N Shimizu, B Skrzypek, R Snihur, J Soedingrekso, A Sogaard, D Soldin, P Soldin, G Sommani, C Spannfellner, GM Spiczak, C Spiering, J Stachurska, M Stamatikos, T Stanev, T Stezelberger, T Sturwald, T Stuttard, GW Sullivan, I Taboada, S Ter-Antonyan, A Terliuk, A Thakuri, M Thiesmeyer, WG Thompson, J Thwaites, S Tilav, K Tollefson, S Toscano, D Tosi, A Trettin, AK Upadhyay, K Upshaw, A Vaidyanathan, N Valtonen-Mattila, J Valverde, J Vandenbroucke, T Van Eeden, N van Eijndhoven, L Van Rootselaar, J van Santen, J Vara, F Varsi, M Venugopal, M Vereecken, S Vergara Carrasco, S Verpoest, D Veske, A Vijai, J Villarreal, C Walck, A Wang, EHS Warrick, C Weaver, P Weigel, A Weindl, J Weldert, AY Wen, C Wendt, J Werthebach, M Weyrauch, N Whitehorn, CH Wiebusch, DR Williams, L Witthaus, M Wolf, G Wrede, XW Xu, JP Yanez, Y Yao, E Yildizci, S Yoshida, R Young, F Yu, S Yu, T Yuan, A Zegarelli, S Zhang, Z Zhang, P Zhelnin, P Zilberman

Abstract:

We report improved measurements of the all flavor astrophysical neutrino spectrum with IceCube by combining complementary neutrino samples in two independent analyses. Both analyses show evidence of a harder spectrum at energies below ∼30 TeV compared to higher energies where the spectrum is well characterized by a power law. The spectrum is better described by a log parabola or a broken power law, the latter being the preferred model. Both, however, reject a single power law over an energy range 5 TeV–10 PeV with a significance >4σ, providing new constraints on properties of cosmic neutrino sources.

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