I work at Universidad Antonio Nariño in Bogota, and I have been part of the ATLAS experiment since 2010. After a two-year stay at CERN, I moved back to Colombia in 2012 and since then, I have continued to do my work on ATLAS from here. Being involved in ATLAS and working from Colombia has been a great experience for me; I get to continue contributing to the physics searches I am involved in at ATLAS, and also do other things like teaching, giving seminars, and doing outreach activities.

A typical day for me starts with a videoconference meeting with one of the ATLAS groups I work with at CERN. The time difference means this is usually quite early, but things here in the city start quite early as well so it does not feel that strange anyway. After the meeting it is half way through the morning and some days I have to teach at the University at that time. Then I have all the afternoons to focus on my work on ATLAS, which is now starting to be all about preparing for Run 2 of the LHC.

For a couple of years I have been involved in a particular search for physics beyond the standard model, looking for a charged Higgs boson, different to the Higgs boson we already found at the LHC (which has zero charge). Our results with the Run 1 data are almost finished, and most of the people in the analysis group, me included, are moving to start preparing the search for the same particle with the Run 2 data. Although there is no data yet, it is important that we anticipate the issues that might arise with the new conditions of the LHC, and also that we prepare all our “machinery” (analysis software) for when the data arrives.

As one of the many improvements ATLAS has made for Run 2, the way in which we analyse and process our data has been changed, to improve its efficiency and compatibility across different analysis groups, so that we can more easily compare our results with other colleagues in a more efficient and faster way. So the first thing I am involved in for Run 2 is in understanding and adapting our Run 1 machinery to this new environment in order to be prepared when the new data arrives. This will help us get new updated results quickly, which for this search should be possible rather soon, hopefully just after the first year of data taking.

The other people in my group are also preparing themselves for Run 2. Our group also works on the system that chooses which events to keep and which ones to discard. This is called the Trigger, and here we are involved in developing a particular tool for identifying low mass particles reconstructed from electrons. Electron identification is in general something our group has been involved in for some time, and all this work will be very relevant as soon as we start taking data again, helping us identify where we need to improve and checking whether our algorithms are working as they should in the new conditions of the LHC.

Other than the research work on ATLAS, I also take remote computing shifts, where I monitor from here the behaviour of the ATLAS computing GRID for eight hours a day. This is part of the service work all of us in the collaboration do to share the load of all the different tasks needed to keep the experiment working properly all year long.

Another thing I enjoy doing here is outreach, trying to encourage young people in doing science and showing them a bit of what we do in ATLAS and why it is interesting and exciting. Just this month we hosted two international masterclasses, where school students come to the university one day and learn about the work that we do, and get to do a “mini” search for a particle with real ATLAS data. At the end of the day we have a video conference with other universities around the world where the same activity is being held, so that they can interact with other students in a different country and compare their results, sort of the way we do in real life in a collaboration like ATLAS.

These activities are important for us, because we are a rather small community here in Colombia doing experimental particle physics, so it is one of our “duties” to reach out to people and let them know about the potential of our research.

In the summer holidays I am usually able to go to CERN for a couple of months which is very nice: I can interact with many people there and hear about their ideas and get involved in new projects for when I return to my home country. This year the detector will already be taking data by the time I arrive, so it will be even better, since I will also take shifts in the control room and be part of the data taking process.

I feel very fortunate to be able to take active part in the very exciting things we do on ATLAS from my home country, and like all of us in the collaboration, looking forward to the new challenges that Run 2 will bring us.

Carlos Sandoval