The Finnish Physical Society (FPS) was founded in 1947 to promote research and public knowledge in physics and support integrity of physicists in Finland. The history of the FPS was summarized in connection with 2018 Physics Days, where the society celebrated the 70-year anniversary. At the time, people collected several blog texts on Finnish physicists. Also, the Particle Physics Division has a long tradition in the FPS. Long enough that the standing chair of the division does not have connection to older activities. Present webpages of the division go down in history to 1997 when the activities of the division were reactivated after “a few years of silence”. Perhaps we should collect the history of the division in a bit more detail? Nevertheless, we are one of the active divisions inside the FPS!

In past few years, the traditional Particle Physics Day -meeting has underwent a renewal. We used to arrange the meeting either in Helsinki or Jyväskylä campus. However, participants gave feedback that local people – understandably – tended to escape to offices during the breaks to take care of small running matters and prioritize talks that have direct relevance to own work. This did not promote discussions or interaction, particularly among younger academicians that did not know each other beforehand. To embrace the communication, the 2017 edition of the Particle physics day was arranged in Hotel Arthur instead of Kumpula campus in Helsinki. The experience was good, and the event has ever since been arranged in hotel conference premises, alternating between Jyväskylä and Helsinki, apart from 2020, when covid-19 pandemic forced us to have a virtual event.

However, the feeling of haste remained in the events. About half of the participants took an early morning train and rushed back home with the afternoon train. It was hard to accommodate all the talks, and the discussion time remained limited. As I remember, moving from campuses to hotels triggered more serious discussions on having a two-day event instead. After a couple of years of pondering, the idea on two-day event was now realized on November 27-28^th 2024 at the Lammi research station. Total of 60 people participated at least for one day, and 56 stayed overnight at Lammi.

The ongoing European Particle Physics Strategy Update (EPPSU) provided a good opportunity to build the two-day program to Lammi. We started the first day hearing four talks that aimed to initialize discussions sessions on EPPSU. Katri Huitu gave an overview of the EPPSU process, Panja Luukka talked from perspective of the European Committee for Future Accelerators (ECFA) and CERN’s Detector Research and Development (DRD) programs, Kenneth Österberg presented the Future Circular Collider (FCC) that CERN has chosen its future flagship project, and Petja Paakkinen and Mikael Myllymäki brough to discussion thoughts from the Early Career Researcher (ECR) community. After the opening presentation, participants were randomly divided into four groups that circulated in tables hosted by the speakers. Finally, after the coffee break, the table discussions were summarized, and we had an open mic among all the participants. As we dedicated the whole first day to this process, we hope that relevant people got a plenty of input to the strategy preparation, and everybody was able to express their opinion and viewpoint.

The first day ended to the division meeting, dinner, and sauna. The Lammi lakeside sauna was spacious and gave an opportunity to swim in the lake, that few brave participants indeed did! Some snacks and beverages were served and people relaxed at the calm evening. The sauna, however, was not as inclusive as the organizers hoped. There wasn’t a separate dressing room, but instead only one large common area. There was only one hot room that also had to be shared with all participants. Hence the environment did not provide privacy, and some participants were not comfortable with the premises. At this point, people divided into sauna and to a common room in the dormitory. After the sauna time was over, remaining people gathered into the common room for chatting and frying sausages at the fireplace, but at this point some had already withdrawn to the rooms. Should we return to Lammi again, one might consider if there are alternatives for the evening program.

The second day resembled a traditional Particle physics day we are used to. The main difference was that we could start earlier and add one session which in turn enabled longer presentations and timetable was not as hectic as it has been. Fortunately, only one presentation had to be cancelled due to a seasonal flue, and this slot was taken by a researcher from the station, who gave a very interesting overview of the activities in Lammi.

Should we make the two-day event as a new norm? This is the question to be answered. We collected feedback from the participants and fortunately many answered the survey. If we choose to have two-day events also in future, one can consider alternative ways to utilize the available time, if a topic for an extensive discussion is not found. Of course, we still need to collect a summary on the expenses. Preliminary it seems that two-day event in a university research station is not necessarily (clearly) more expensive for the projects compared to a one-day event in a hotel. While one-day event at campus would be the cheapest option, the benefits from allocation of some project resources seem indisputable.

I have had a pleasure to serve as a chair of the division for the past three years, added with some more years in the board. Hence it is my time to step down from the position, in accordance with the division rules stating that no individual should chair more than three years. The new board of the division is, in alphabetical order following the first name, Erik Brücken, Hanna Lempiäinen, Henning Kirschenmann, Ilkka Helenius, Matti Heikinheimo, and Pyry Runko. The new board will select among themselves the chair and secretary, who will be officially endorsed during the next Physics Days in Oulu in March 2025. I am looking forward participating to 2025 Particle physics day(s), no matter the exact choices the new board makes on the arrangements!

Sami Räsänen