Large Hadron Collider search rules out quantum black holes with certain properties

Physicists at UC Santa Barbara have extended the search for microscopic black holes created within the Large Hadron Collider, demonstrating a novel method for detecting new particles beyond simply finding the target itself. While evidence of these fleeting objects remains elusive, researchers emphasize that even a negative result yields valuable scientific knowledge. “It’s not a dead-end,” said Danyi Zhang, a graduate student researcher at the Incandela Lab. This work addresses a long-standing discrepancy between the observed energy scale of the universe and the fundamental Planck scale, guiding future theoretical development and experimental searches at CERN. LHC Extends Search for Quantum Black Holes The Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider has broadened the scope of searches for microscopic black holes, establishing a new methodology applicable to identifying any novel particle, not solely black holes. This expanded search, detailed in Progress in High Energy Physics, has ruled out the existence of quantum black holes with specific characteristics, signifying valuable scientific knowledge even in the absence of detection.

The team’s work establishes concrete limits on theoretical possibilities, shifting the focus of future investigations. This investigation stems from a decades-old hypothesis suggesting that, given sufficient energy and the potential existence of extra spatial dimensions, a concept integral to string theory, the LHC could momentarily generate quantum black holes during proton-proton collisions. Though these black holes would decay almost instantly, physicists theorized their decay patterns could be detectable, prompting initial searches by the ATLAS and CMS collaborations. With significantly larger datasets now available, researchers aimed to extend these searches to higher energy ranges, increasing the probability of detection should these fleeting objects exist. “If you want to describe things that are small, you go to quantum field theory. We have the Standard Model to describe all the particles, and it performs exceptionally well in practice. And when you go to the very, very big you have general relativity that would describe how big and massive objects behave,” explained Tamas Vami, a researcher involved in the study. Reconciling these two pillars of modern physics drives the search for quantum black holes. The methodology employed by Vami and Zhang differs from typical “black box” machine learning approaches, offering a supervised method that allows researchers to examine the underlying mathematical principles driving the results. This transparency helps validate findings and understand the limits of the search. The Planck scale, representing a fundamental energy level, remains significantly higher than the energies currently observable within the universe, and theorists posit that new physics detectable at the LHC could bridge this gap. The current search, while yielding no evidence of quantum black holes, actively narrows the range of possibilities for these theoretical particles. “They predict a whole range of places a particle could be hiding. [Our] search clears out part of that range and says ‘not here,’ and over time the map of where new physics could still be, shrinks,” Zhang explained.

The team’s findings are not a setback, but rather a refinement of the search parameters, guiding future theoretical development and experimental design. “It’s not a dead-end,” Zhang added. CERN’s commitment to pushing the boundaries of particle physics is bolstered by its expanding involvement in quantum technology. The CERN Quantum Technology Initiative, launched in 2020, explores how quantum computing can accelerate data analysis and simulation. This initiative includes partnerships with companies like IBM Quantum and Google Quantum AI, using their expertise to tackle the computational challenges inherent in analyzing LHC data. CERN’s collaboration with Qilimanjaro Quantum Tech promotes global access to quantum computing resources. This connection between particle physics and quantum technology is exemplified by recent work where Atlas Technologies assisted Oxford physicists in tracking entanglement in Z bosons produced at the LHC, demonstrating the growing interplay between these fields. Steven Giddings, a physics theorist, notes that “You form a black hole, and it immediately disintegrates. But it has a very spherical decay signature, lots of things going in all directions.” Theorists will continue to generate ideas, but experimental data remains essential for progress. They wouldn’t stick around very long – if you made one, it would disintegrate immediately. Steven Giddings, UCSB physics theorist Extra Dimensions & Potential for Microscopic Black Hole Formation Researchers assessed the summed energy of decay products to identify potential signals, a method applicable to a broader range of theoretical physics investigations. “So we basically just take the energy of these particles that are decay products of whatever was created in the collision and sum them together. And if the sum is large enough, we can say that this is the region where we are likely to find the signal,” explained an investigator involved in the analysis.

The team’s findings establish a concrete exclusion limit, demonstrating that quantum black holes possessing specific characteristics are unlikely to exist within the energy range explored, and, by extension, constrain certain theoretical models proposing extra spatial dimensions. CMS Sphericity Analysis Detects Black Hole Decay Signatures Researchers found no evidence of black hole creation within the analyzed data, but the refined search parameters represent a valuable constraint on theoretical models positing extra spatial dimensions.

The team’s analysis leveraged the immense energy generated by proton-proton collisions at the LHC, probing distances as small as 10-20 meters, a scale comparable to the size of an atom relative to a human. “At the LHC, we’re colliding particles at extremely high energies, which corresponds to tiny distance scales,” explained Incandela, highlighting the collider’s capacity to explore physics at unprecedented scales. The search focused on identifying highly spherical decay signatures, predicted as a characteristic of disintegrating quantum black holes, where energy is released in all directions. Planck Scale & Hierarchy Problem Motivate LHC Black Hole Search This exclusion isn’t a setback, but a valuable constraint on theories proposing extra dimensions as a solution to the hierarchy problem, the question of why gravity is so much weaker than other fundamental forces. As with microscopy, higher energies allow probing of smaller distances, and the LHC’s reach now defines a lower bound on the scale of these potential dimensions. The methodology employed in this search extends beyond the initial target of black hole detection, representing a novel approach applicable to a wider range of particle physics investigations. Unlike “black box” machine learning algorithms, the team utilized a supervised method, allowing for detailed examination of the underlying mathematics driving the results. “So what do you need to make a black hole? Well, you have to compress some energy into a really small volume,” explained a researcher, highlighting the extreme conditions required for such events. We developed the idea of the phase space between events, which can be combined with SVM to help the search.

Nathaniel Craig The researchers documented a search for these configurations alongside the black hole hunt, demonstrating the versatility of their phase-space distance tool, a method for identifying unusual decay signatures. “They wouldn’t stick around very long — if you made one, it would disintegrate immediately,” a researcher noted, describing the fleeting nature of these theoretical phenomena. The implications of these negative results are significant for theorists. While the absence of black holes at the LHC doesn’t invalidate the search for new physics, it does force a reevaluation of existing models. According to one estimate, creating even the smallest, microgram-sized black holes would require particle collisions a million billion times more energetic than those currently achievable at the LHC. “Basically, the gravitational force gets stronger, faster, as you go to shorter distances,” explained a researcher, outlining the challenges of probing these extreme energy scales. CERN was founded in 1954 and headquartered in Geneva, Switzerland, and currently employs over 17,000 scientists and engineers from 113 countries. The CERN openlab collaborates with technology companies like Qilimanjaro Quantum Tech, IBM Quantum, and Google Quantum AI on quantum algorithm development for high-energy physics. “Had we found evidence, we could have begun to directly study quantum gravity,” said a researcher, emphasizing the potential payoff of this research. The process both forces better ideas and affects the design of new experiments and detectors, ensuring that the pursuit of knowledge continues even in the face of elusive phenomena. So what do you need to make a black hole? Well, you have to compress some energy into a really small volume. Giddings, referring to those massive voids in spacetime, areas of extreme gravity that can eat whole Null Result Refines Limits on Quantum Black Hole Properties This approach, utilizing a phase-space distance tool, allows researchers to efficiently map and exclude regions where potential particles could exist, even in the absence of direct observation. Researchers initially focused on the classical behavior of black holes, massive voids in spacetime, but shifted attention to the potential for quantum black holes arising from these collisions and undiscovered extra dimensions. The LHC’s capability to probe distances as small as 10-20 meters, achieved through extremely high-energy collisions, was important to this investigation. This ability to examine such minute scales offered the theoretical possibility of spacetime folding upon itself, creating a quantum black hole. While initial concerns regarding the safety of these collisions were addressed through comparisons with cosmic ray interactions, the search continued, driven by the potential to unify all known fundamental forces. This transparency is particularly important as the search extends to address the hierarchy problem, a long-standing discrepancy between the gravitational force and other fundamental forces. The findings also provide valuable constraints on theoretical models, guiding future research and narrowing the range of possibilities. “We will be putting constraints on what theories can be true,” said a researcher. This investment extends beyond accelerating existing analyses, with CERN also transferring its expertise in superconducting magnet technology, refined over decades of building particle accelerators, to the development of superconducting qubits. “The best guide is experimental data, and that’s what we’d really like to have,” said a researcher, emphasizing the importance of empirical evidence in tackling “the most profound problem in theoretical physics.” The work at the LHC, pushing the boundaries of the Standard Model, continues to refine our understanding of the universe and its fundamental components. Had we found evidence, we could have begun to directly study quantum gravity. Tamas Vami, a researcher in the Compact Muon Solenoid (CMS) experiment who is conducting his postdocto Even without detecting these fleeting objects, the process forces refinement of existing models and informs the design of future experiments. According to one theorist, achieving the energies necessary to create even microgram-sized black holes, a million billion times the current LHC’s capacity, would require a significant leap in technology. “Theorists will continue to generate ideas and maybe we will do better in figuring things out without experimental data, but it will be difficult,” he said, acknowledging the crucial role of ongoing experimentation in unraveling the mysteries of the universe.

The team’s work, published in Progress in High Energy Physics, underscores the value of negative results in the scientific process, providing critical constraints on theoretical possibilities and guiding the search for new physics beyond the Standard Model. People were more focused on the classical behavior of black holes. Giddings, referring to those massive voids in spacetime, areas of extreme gravity that can eat whole Source: https://news.ucsb.edu/2026/022819/physicists-extend-search-quantum-black-holes-lhc More like thisQuantum Research NewsNew Quantum Spintronics Center Launches with German-Korean TiesQuantum Research NewsTemperature has less impact on this hBN qubit’s stabilityPhysicsNew magnets aim to meet positron demands of 91km colliderPhysicsFQXi finds Schrödinger’s cat in a box models quantum events in spacetimeStay currentSee today’s quantum computing news on Quantum Zeitgeist for the latest breakthroughs in qubits, hardware, algorithms, and industry deals. Tags: