K. Shchelina

A group of Early-Career Researchers (ECRs) has been given a mandate from the European Committee for Future Accelerators (ECFA) to debate the topics of the current European Strategy Update (ESU) for Particle Physics and to summarise the outcome in a brief document [1]. A full-day debate with 180 delegates was held at CERN, followed by a survey collecting quantitative input. During the debate, the ECRs discussed future colliders in terms of the physics prospects, their implications for accelerator and detector technology as well as computing and software. The discussion was organised into several topic areas. From these areas two common themes were particularly highlighted by the ECRs: sociological and human aspects; and issues of the environmental impact and sustainability of our research.

The process $pp → pμ^{+} μ^{−}$ $p^{∗}$ has been observed at the LHC for dimuon masses larger than 110 GeV in $pp$ collisions at $\sqrt{s}$ = 13 TeV. Here $p^{(∗)}$ indicates the second proton is undetected, and either remains intact or dissociates into a low-mass state $p^{∗}$. The scattered proton has been measured in the CMS-TOTEM Precision Proton Spectrometer (CT-PPS). The spectrometer operated for the first time in 2016, collecting $∼10fb^{−1}$ of data in regular, high-luminosity fills. The procedure for detector alignment, optics corrections, and data analysis including background estimate are described. The present data constitute the first evidence of this process at such masses. They also demonstrate that CT-PPS performs as expected.