On the morning of 19 August 2026, a lecture in the 【NanGaoShi·Physics Seminar】, hosted by the School of Physical Science and Technology at Nanjing Normal University, was held in Meeting Room 437 of Xingjian Building. Guillelmo Gomez-Ceballos, Physics Coordinator of the CMS experiment at CERN and Principal Research Scientist at the Massachusetts Institute of Technology (MIT), was invited to deliver an academic talk entitled "Physics with CMS Run 3 Data". The seminar was chaired by Professor Kai Yi of the School and attended by faculty members, graduate students, and undergraduate students from the School of Physical Science and Technology.

At the beginning of the lecture, Gomez-Ceballos introduced the CMS (Compact Muon Solenoid) experiment, one of the flagship multipurpose experiments at the Large Hadron Collider (LHC). He outlined its broad physics program, which encompasses precision measurements of the Standard Model, searches for new physics, Higgs boson and flavor physics, as well as studies of heavy-ion collisions. With the continued accumulation and analysis of Run 3 data, CMS has entered an important new phase of its physics program.

Discussing trigger and data-acquisition strategies, Gomez-Ceballos highlighted the ways in which CMS is extending its physics reach in proton-proton collisions. He explained that the CMS trigger strategy is built around three complementary approaches, the standard physics stream, the Parking stream, and the Scouting stream, which together allow the experiment to record and study events that would otherwise be inaccessible, particularly at low transverse momentum. Drawing on his experience with the CMS data-acquisition system, he emphasized that these evolving trigger and data-taking strategies have enabled CMS to collect a Run 3 dataset substantially larger than that accumulated during Run 2.

The lecture then covered recent developments in flavor and heavy-ion physics. In flavor physics, Gomez-Ceballos highlighted CMS measurements of CP violation in D->pipi and D->KK decays using Parking-stream data, as well as recent studies of the fully charmed tetraquark family. Using both Run 2 and Run 3 data, CMS has performed detailed studies of the X(6600), X(6900), and X(7100) structures, establishing evidence for all three states and studying their interference. In heavy-ion physics, he discussed CMS observations of significant high-pT particle-yield suppression in small collision systems, including oxygen-oxygen (OO) and neon-neon (NeNe) collisions, providing new experimental information relevant to the study of the quark-gluon plasma (QGP).

In the area of Higgs boson physics, Gomez-Ceballos reviewed recent CMS results on precision measurements of Higgs properties, searches for rare Higgs decays, and studies of di-Higgs production. Among the topics discussed were constraints on the Higgs-charm coupling, differential cross-section measurements of H->ZZ->4l, and the CMS-ATLAS combination of non-resonant di-Higgs production. He emphasized the growing role of machine-learning techniques in improving the sensitivity and precision of Higgs measurements, noting that these developments are opening a new era of precision Higgs physics.

He also highlighted the rapidly increasing pace of CMS publications. With Run 2 analyses continuing to reach completion while the first Run 3 results are emerging, the Collaboration is now entering an especially productive period. Although Run 3 data taking is approaching its conclusion, the physics exploitation of the dataset is only beginning, with many important measurements and searches expected over the coming years.

In the final part of the lecture, Gomez-Ceballos outlined the CMS upgrade program for the High-Luminosity LHC (HL-LHC). Looking ahead, he emphasized that CMS will continue to play a leading role in precision tests of the Standard Model, searches for physics beyond the Standard Model, flavor physics, and heavy-ion physics, providing a unique experimental platform for exploring the fundamental laws of nature.

The lecture was followed by a lively discussion between the speaker and faculty and students. Questions covered a wide range of topics, including the CMS trigger strategy, the applications of Parking-stream data, searches for invisible Higgs decays, and studies of B->mumu. The seminar provided participants with a broad overview of the latest physics results from CMS and the opportunities offered by the Run 3 dataset, while also opening new avenues for academic exchange and collaboration.

Following the seminar, Professor Kai Yi's CMS research group held an internal discussion session with Gomez-Ceballos. Members of the group presented updates on several ongoing physics analyses and discussed key issues arising in their work. For each analysis, he provided targeted and constructive suggestions, drawing on his broad experience across the CMS physics program and his perspective as Physics Coordinator. He also shared with faculty members and students reflections from his own academic career, including experiences and lessons related to personal development, research choices, and career planning.

The discussion provided valuable scientific and career perspectives for the group and further strengthened the exchange between the Nanjing Normal University CMS research team and the broader CMS physics coordination. The visit also created new opportunities for continued academic interaction and future collaboration.

Speaker biography:

Guillelmo Gomez-Ceballos is a Spanish physicist and Principal Research Scientist at the Massachusetts Institute of Technology (MIT). He currently serves as Physics Coordinator of the CMS experiment at CERN, where he oversees the Collaboration's broad scientific and physics analysis program. His research focuses on precision tests of the Standard Model, Higgs boson physics, electroweak interactions, and searches for physics beyond the Standard Model. Over the course of his career, he has played leading roles in CMS physics analysis, detector operations, and the scientific coordination of the Collaboration, contributing to both its research program and its long-term scientific strategy.