Olga Botner, a physics professor at Uppsala University, was elected IceCube spokesperson in May 2013, just a few months before IceCube published the discovery of astrophysical neutrinos in Science. Four years later, astrophysical neutrinos have revealed many interesting things about the most extreme environments in the universe, and IceCube has also delivered outstanding results in neutrino physics, cosmic ray physics, and dark matter searches.
Now, it’s time to pass the baton to the new spokesperson, Darren Grant, a professor of physics at the University of Alberta, who will lead the collaboration for the next two years.
IceCube is still a young experiment, and it feels like there is always something new going on. But, a spokesperson transition brings us the perfect moment to talk about accomplishments and future plans. In this interview, Olga and Darren share their thoughts.
Q: What would you highlight from the last two years in IceCube?
Olga Botner (O): I think there are many results worth mentioning. For instance, two important outcomes are the confirmation of the HESE results with upgoing muon neutrinos and the discovery of the most energetic neutrino ever observed, which gave rise to a muon track depositing 2.6 PeV energy in IceCube. This neutrino has an energy 100 million times higher than those of solar neutrinos. I’m also excited by our sterile neutrino result and our increasingly precise neutrino oscillation parameters.
Darren Grant (D): I agree with Olga, those were outstanding results. I would also like to add the maturation of IceCube’s real-time follow-up program and the concerted effort of the collaboration behind the IceCube-Gen2 activities resulting in submission of a proposal for the first phase of the project late last year.
O: And let me comment on our community, too, because as a team we have also been developing constantly. I really appreciate the welcoming atmosphere, allowing new students to be rapidly included in the IceCube community, especially since the older students make an effort to reach out to the newcomers.
Q: And, what are the challenges and opportunities ahead?
D: Well, IceCube is a remarkable instrument that continues to perform above expectations. Considering all that has already been accomplished with the detector, many of our results are still statistically limited, meaning there remains enormous potential in future measurements. The challenge is to continue to refresh our approaches so that we can extract the most information from the growing IceCube data set.
O: Yes, it is good to see IceCube adding year upon year of amazing data. Four years ago we could announce the discovery of astrophysical neutrinos. Adding more and more data, we have learned that our a priori expectations about the behavior of this astrophysical flux were too simplistic. We now know that what we believed were the most likely sources of these neutrinos can, in the best case, only contribute a fraction of what we observe. The challenge now is to attempt to figure out what Nature is trying to tell us. To do this we have to make the best possible use of all of our data sets. But, as Darren mentioned before, the exciting opportunities also hinge upon the fact that over the past year we have developed the real-time trigger system and our fast response system to be able to rapidly engage the multimessenger community. This allows us to promptly investigate transient phenomena, and at the end of the day this might be how we’ll discover the first point source.
Q: How do you view IceCube as a group in the astrophysics and particle physics communities?
D: I think everyone would agree that in astrophysics IceCube is at the forefront of the field. In particular, the role of neutrinos within the multimessenger astronomy community is coming of age, and IceCube has established the foundation for this.
O: I subscribe to Darren’s words. IceCube is unique, not only due to the cool detector location but also because we are paving the way to explore the “coolest” objects in the universe—black holes and their surroundings—in an unprecedented way. This is a dream come true, made possible by adapting some of the methods used in particle physics. The IceCube Collaboration works in many ways like a collaboration within particle physics. But compared to other particle physics collaborations, IceCube is small. It is great to be able to recognize most of your collaborators when you meet face to face.
D: I think that IceCube has really surprised many in the particle physics community, in particular with the atmospheric neutrino oscillation, sterile neutrino, and indirect dark matter searches to date. The success of applying the IceCube detector design to create a huge volume detector for particle physics measurements has started to shape the vision for future projects; it is incredibly exciting to see.
Q: Both of you have been in IceCube for many years, leading efforts at different levels. Would you be willing to try to guess what IceCube’s next breakthrough might be?
O: I believe that by honing our understanding of the ice we’ll soon be able to make better use of cascades in many more of our analyses, increasing our sensitivity. In particular, I believe this will help us to discover extended neutrino sources, which would be a big breakthrough.
D: Taus! I think we are going to soon see the low-energy analyses for tau neutrino appearance reach completion. And at high-energy, I think the continued improvements of our analyses will finally uncover the elusive golden signature event. Longer term, I anticipate that the real-time follow-up program will discover the first high-energy neutrinos correlated with astrophysical events.
Q: Olga, the collaboration wholeheartedly thanked you for your leadership during these four years. And this was not the first time that you had served the team, since you had already chaired the publications and the speakers committees for several years. What would you like to say to the younger members of the collaboration?
O: IceCube is steadily producing amazing data, and now the challenge is to reconcile all our data and figure out what Nature is trying to tell us. This is an exciting time to be a member of the IceCube Collaboration.
Q: Darren, Olga’s accomplishments certainly leave high expectations for the new spokesperson. As a very active member of the collaboration, you have shared many of these accomplishments with her and the rest of the collaboration. But, leading the team brings new challenges. Can you tell us a bit more about your decision to run for spokesperson?
D: There was a great desire to give back to the people and the project that have meant so much to my career development. My experiences before IceCube were in very low energy neutrino measurements (SNO) and dark matter searches (CDMS). And within IceCube my main activities have mostly been related to those early experiences. I am really looking forward to expanding my interests within IceCube’s rich scientific program in this new role, and sharing some of the positive unique elements from my own background with the broad collaboration.
Q: And, what are your main goals for the coming two years?
D: My main goals are related to seeing the collaboration continue its rapid growth in the fields of astronomy, astrophysics, and particle physics. We have the opportunity to build on an incredible momentum that has been established, and by continuing to streamline many of our processes, we can seize on new opportunities. I also want to focus effort on developing new methods to promote the vibrant group of young scientists who really make up the core of the collaboration. In addition, one of my highest priorities is continuing to assist in the crucial developments that will bring the next generation IceCube detector to reality.