Full speed ahead Layout of the SHiP experiment, with the target on the left and the experiment in the ECN3 hall. Credit: SHiP collaboration.

In a significant step forward for particle physics, CERN’s Research Board recently approved the SHiP (Search for Hidden Particles) experiment, slated to begin commissioning and operations in 2031. SHiP aims to explore "hidden sectors" by searching for potential new particles and interactions that could reshape our understanding of the universe.

Despite the success of the Standard Model, several mysteries remain, such as dark matter, neutrino masses, and cosmic baryon asymmetry. Hidden sectors, consisting of particles that interact very feebly with the Standard Model particles, could provide answers. Conceived in 2013, SHiP will use high-intensity proton beams from CERN's Super Proton Synchrotron (SPS) accelerator to investigate these elusive sectors, focusing on particles with masses from MeV to several GeVs.

Professor Golutvin, spokesperson of the SHiP experiment, stated: “The approval of SHiP marks a new era in the search for hidden sector particles. SHiP has the unique possibility to solve several of the major problems of the Standard Model of particle physics by discovering particles that have never been seen before.”

SHiP will employ a beam-dump configuration to produce a vast quantity of photons, charm hadrons, and beauty hadrons. Its sensitivity lies in its ability to efficiently suppress the backgrounds from ordinary particles and reconstruct and identify the decay modes of the new particles fully. SHiP will also search for light-dark matter by detecting the recoil of atomic electrons or nuclei. Additionally, its optimization for studying tau neutrinos and neutrino-induced charm production will enhance our understanding of these fundamental particles.

Strategically sharing beam time with other fixed-target experiments and the LHC, SHiP expects around 6 x 10²⁰ protons on target over 15 years. The facility's layout has been informed by recent optimization studies, featuring two sections: the scattering and neutrino detector, and the hidden-sector decay spectrometer.

Instead of colliding particles together as most current experiments do, the new Search for Hidden Particles (SHiP) experiment will crash them into a large block of material, smashing all the particles into smaller bits. The diagram below illustrates why this 'fixed target' approach is more effective. (Credits: BBC research).

Next Steps: From Concept to Reality

Following approval, the SHiP collaboration's immediate focus shifts to developing detailed technical design reports (TDRs). Key components like the proton target, designed to withstand 2.6 MJ of energy every 7.2 seconds, and an active muon shield to reduce background, will receive special attention, says senior CERN physicist and project leader of SHiP, Dr. Richard Jacobsson. “With sufficient funding, the TDR phase will last about three years, followed by construction. Barring delays, the facility's commissioning is projected for the end of 2030, with the detector operational in 2031. This timeline allows a year and a half of data collection before the next long shutdown of CERN's accelerator complex in the current accelerator schedule. I'm delighted that CERN has recognized the potential of this experiment to transform the landscape of particle physics and has agreed to build the facility needed for the experiment.”

The Future of Hidden Sector Exploration

The decision to proceed with SHiP follows extensive deliberations within CERN's scientific community in which SHiP's broad scope and unique potential to unlock new chapters in our understanding of the universe's fundamental building blocks and the forces that govern their behavior gave it the edge.

European scientists are also gearing up to explore "ghost particles" like neutrinos in unprecedented detail. This aligns with SHiP's goals of studying neutrino interactions, in particular of tau neutrinos, crucial for shedding light on the enigmatic properties of these particles.

As the SHiP experiment progresses, it aims to significantly contribute to particle physics, offering insights that could redefine our understanding of the universe's hidden components.Pushing the boundaries of known physics, SHiP not only promises to unearth answers to longstanding questions but also to pose new questions that could drive the next generation of research. With every discovery, SHiP will pave the way for future explorations, potentially leading to a new era where the invisible becomes visible and the unknown becomes known. The scientific community eagerly awaits the revelations SHiP will bring, standing on the brink of discoveries that could reshape the very foundation of physics.