- The CERN Large Hadron Collider (LHC) Forward Physics and Diffraction Working Group met at the Institute for Theoretical Physics (IFT, UAM–CSIC) in Madrid, from September 29 to October 2.
- Theoretical and experimental physicists from around the world discussed the latest advances, as well as new experiments, approaches, and technologies in view of the High-Luminosity LHC (HL-LHC) project, scheduled to begin operation in 2030.
- Research at the most fundamental limits of matter could lead to unexpected applications, such as the measurement of cosmic rays and even improved treatments for certain types of cancer.
By: Elisa Ramírez
Madrid, September 3, 2025.– The world’s most powerful particle accelerator, CERN’s Large Hadron Collider (LHC), is in the process of increasing its luminosity tenfold—that is, the number of collisions per second—in order to enhance its operational capacity. The so-called High-Luminosity Project will start operating in 2030, and both theoretical and experimental physicists are already joining forces to collaborate on the development of experiments with new approaches and technologies suited to the collider’s future potential.
The latest conference of one of the LHC’s ten working groups took place at the Institute for Theoretical Physics (IFT UAM–CSIC) in Madrid, to share the most recent advances in forward physics, which deals with small-angle scattering.
Christophe Royon, a renowned researcher at the University of Kansas and one of the group’s coordinators, explained the aim of the meeting: “It’s about starting to think about new measurements and, if necessary, new detectors for the High-Luminosity program. Although it will be fully developed in about 10 years, now is the time to discuss these ideas.”
With the new LHC era underway, Royon emphasizes that advances in electronics and computing that accompany the development of accelerator physics also find applications in other fields.
Christophe Royon, researcher at the University of Kansas. / IFT.
Unexpected Applications: from Cosmic Ray Measurement to Cancer Treatments
Research at the most fundamental limits of matter requires the development of increasingly powerful and precise technologies, which sometimes find applications that transcend particle detector physics and transform society. “A very well-known example is the web we all use today: it was born at CERN as a communication tool for researchers,” Royon recalls. The World Wide Web, the first website and web server, was created in 1989 by Tim Berners-Lee, then a scientist at the prestigious European laboratory in Geneva, Switzerland.
From his own research on detectors, Royon collaborates with CERN but also on applications ranging from cosmic ray measurement to new medical techniques. “The fast silicon detector we have been developing at the University of Kansas can be used to measure doses in external beam radiotherapy for cancer treatment,” he highlights.
This type of therapy targets photons, protons, or electrons at specific areas of the body where tumors are located. However, the doses administered are difficult to control. “It’s essential to know the doses delivered with a very intense and short-duration beam, such as one millisecond, but currently no one can perform this type of measurement. That’s why the detector we are developing would be very useful,” says Royon, who is collaborating in this line of research with the U.S. National Institutes of Health (NIH) and carrying out tests at the Texas Medical Center.
The Relevance of Forward Physics
The LHC Forward Physics and Diffraction Working Group is one of ten working groups of CERN’s LHC Physics Center (LCCP), whose goal is to provide a common discussion forum for theoretical and experimental researchers. Created in 2013 and currently coordinated by Lydia Beresford and Jesse Liu (ATLAS), Christophe Royon (CMS), and Murilo Rangel (LHCb), this group meets at least twice a year, once at CERN and once at international centers. This is the third time it has held one of its conferences in Madrid.
Agustín Sabio Vera, director of the IFT and a member of the group, clarifies what forward physics refers to: “It is a type of physics that explores a unique regime in high-energy collisions: the one in which the resulting particles emerge almost in the same direction as the beam, in the high-rapidity region.” And he highlights its significance: “The physical characteristics of this region provide an advantage for studying fundamental phenomena, from diffractive scattering and quantum chromodynamics dynamics at extreme energy scales to gluon saturation, all of which are of vital importance for both LHC and cosmic ray physics.”
For his part, Royon emphasizes the presence of this type of physics in experiments: “It is basically related to all detectors that are in the beam direction. For example, the four main LHC experiments, ATLAS, CMS, LHCb, and ALICE, as well as smaller additional experiments such as TOTEM.”