On April 5, 2025, the CMS, LHCb, ALICE and ATLAS collaborations at the Large Hadron Collider at CERN were honored with the Breakthrough Prize in Fundamental Physics by the Breakthrough Prize Foundation. The prize is awarded to the four collaborations, which unite thousands of researchers from more than 70 countries, and concerns the papers authored based on LHC Run-2 data up to July 2024. It was received by the spokespersons who led the collaborations during that time. 

The prize was awarded to the collaborations for their “detailed measurements of Higgs boson properties confirming the symmetry-breaking mechanism of mass generation, the discovery of new strongly interacting particles, the study of rare processes and matter-antimatter asymmetry, and the exploration of nature at the shortest distances and most extreme conditions at CERN’s Large Hadron Collider”.

“I am extremely proud to see the extraordinary accomplishments of the LHC collaborations honoured with this prestigious Prize,” said Fabiola Gianotti, Director-General of CERN. “It is a beautiful recognition of the collective efforts, dedication, competence and hard work of thousands of people from all over the world who contribute daily to pushing the boundaries of human knowledge.”

Following consultation with the experiments’ management teams, the Breakthrough Prize Foundation will donate the $3 million Prize to the CERN & Society Foundation. The Prize money will be used to offer grants for doctoral students from the collaborations’ member institutes to spend research time at CERN, giving them experience in working at the forefront of science and new expertise to bring back to their home countries and regions.

Many current and past UMD physicists have contributed to the CMS and LHCb experiments. During run 2, Alberto Belloni was project leader for the CMS HCAL, and Sarah Eno was USCMS Collaboration board deputy chair. 

ATLAS and CMS are general-purpose experiments, which pursue the full programme of exploration offered by the LHC’s high-energy and high-intensity proton and ion beams. They jointly announced the discovery of the Higgs boson in 2012 and continue to investigate its properties.

"This prize recognises the collective vision and monumental effort of thousands of ATLAS collaborators worldwide", says ATLAS spokesperson Stephane Willocq. "Their talent and dedication, and the support of our public funding agencies, enabled the scientific breakthroughs that are being celebrated today. These results have transformed our understanding of the Universe at the most fundamental level.”

"CMS is deeply honoured to receive this prestigious prize,” said CMS spokesperson Gautier Hamel de Monchenault. “Through continuous innovation in exploiting the data from the Large Hadron Collider over the past fifteen years, the CMS collaboration is conducting a thorough characterisation of the Higgs boson, exploring the electroweak scale and beyond and probing the hot, dense state of nuclear matter that prevailed in the early Universe.”

ALICE studies quark-gluon plasma, a state of extremely hot and dense matter that existed in the first microseconds after the Big Bang, while LHCb explores minute differences between matter and antimatter, violation of fundamental symmetries and the complex spectra of composite particles (“hadrons”) made of heavy and light quarks, among other things.

“The ALICE collaboration is honoured to receive the Breakthrough Prize for the investigation of the properties of the hottest and densest matter available in a laboratory, quark-gluon plasma”, says ALICE spokesperson Marco Van Leeuwen. “The new grants funded through this prize will contribute to training the next generation of ALICE scientists.”

"The award of the 2025 Breakthrough Prize is a great honour for the LHCb collaboration. It underlines the importance of the many measurements made by the LHCb experiment in flavour physics and spectroscopy through the exploration of subtle differences between matter and antimatter and the discovery of several new heavy quark hadrons”, says LHCb spokesperson Vincenzo Vagnoni.

By performing these extraordinarily precise and delicate tests, the LHC experiments have pushed the boundaries of knowledge of fundamental physics to unprecedented limits. They will continue to do so with the upcoming upgrade of the Large Hadron Collider, the High-Luminosity LHC, which aims to ramp up the performance of the LHC, starting in 2030, in order to increase the potential for discoveries.

Original story: https://home.cern/news/press-release/knowledge-sharing/lhc-experiment-collaborations-cern-receive-breakthrough-prize

Post-doctoral Associate Stephen Sclafani has been selected for the American Physical Society’s Ceclia Payne-Gaposchkin Doctoral Dissertation Award, which recognizes doctoral thesis research in astrophysics and encourages effective written and oral presentation of research results. Steve Sclafani at the South Pole.

Members of the UMD group include Brian Clark, Kara Hoffman, Greg Sullivan, Erik Blaufuss, Michael Larson, Rachel Procter-Murphy, Aishwarya Vijai, Taylor St Jean, Shannon Gray, Ergis Shaini, Zoe Brunton, Rohan Panchwagh and Santiago Sued. 

More information about Sclafani's work can be found on the Drexel University College of Arts and Sciences website: https://drexel.edu/coas/news-events/news/2025/March/physics-alum-awarded-for-icecube-research/

On March 24, 2025 at the annual Rencontres de Moriond conference taking place in La Thuile, Italy, the LHCb collaboration at CERN reported a new milestone in our understanding of the subtle yet profound differences between matter and antimatter. In its analysis of large quantities of data produced by the Large Hadron Collider (LHC), the international team found overwhelming evidence that particles known as baryons, such as the protons and neutrons that make up atomic nuclei, are subject to a mirror-like asymmetry in nature’s fundamental laws that causes matter and antimatter to behave differently. The discovery provides new ways to address why the elementary particles that make up matter fall into the neat patterns described by the Standard Model of particle physics, and to explore why matter apparently prevailed over antimatter after the Big Bang.View of the LHCb experiment in its underground cavern (image: CERN) View of the LHCb experiment in its underground cavern (Credit: CERN)

First observed in the 1960s among a class of particles called mesons, which are made up of a quark–antiquark pair, the violation of “charge-parity (CP)” symmetry has been the subject of intense study at both fixed-target and collider experiments. While it was expected that the other main class of known particles – baryons, which are made up of three quarks – would also be subject to this phenomenon, experiments such as LHCb had only seen hints of CP violation in baryons until now.

“The reason why it took longer to observe CP violation in baryons than in mesons is down to the size of the effect and the available data,” explains LHCb spokesperson Vincenzo Vagnoni. “We needed a machine like the LHC capable of producing a large enough number of beauty baryons and their antimatter counterparts, and we needed an experiment at that machine capable of pinpointing their decay products. It took over 80 000 baryon decays for us to see matter–antimatter asymmetry with this class of particles for the first time.”

Particles are known to have identical mass and opposite charges with respect to their antimatter partners. However, when particles transform or decay into other particles, for example as occurs when an atomic nucleus undergoes radioactive decay, CP violation causes a crack in this mirror-like symmetry. The effect can manifest itself in a difference between the rates at which particles and their antimatter counterparts decay into lighter particles, which physicists can log using highly sophisticated detectors and data analysis techniques. 

The LHCb collaboration observed CP violation in a heavier, short-lived cousin of protons and neutrons called the beauty-lambda baryon Λ_b, which is composed of an up quark, a down quark and a beauty quark. First, they sifted through data collected by the LHCb detector during the first and second runs of the LHC (which lasted from 2009 to 2013 and from 2015 to 2018, respectively) in search of the decay of the Λ_b particle into a proton, a kaon and a pair of oppositely charged pions, as well as the corresponding decay of its antimatter counterpart, the anti-Λ_b. They then counted the numbers of the observed decays of each and took the difference between the two.

The analysis showed that the difference between the numbers of Λ_b and anti-Λ_b decays, divided by the sum of the two, differs by 2.45% from zero with an uncertainty of about 0.47%. Statistically speaking, the result differs from zero by 5.2 standard deviations, which is above the threshold required to claim an observation of the existence of CP violation in this baryon decay.

While it has long been expected that CP violation exists among baryons, the complex predictions of the Standard Model of particle physics are not yet precise enough to enable a thorough comparison between theory and the LHCb measurement.

Perplexingly, the amount of CP violation predicted by the Standard Model is many orders of magnitude too small to account for the matter–antimatter asymmetry observed in the Universe. This suggests the existence of new sources of CP violation beyond those predicted by the Standard Model, the search for which is an important part of the LHC physics programme and will continue at future colliders that may succeed it.

“The more systems in which we observe CP violations and the more precise the measurements are, the more opportunities we have to test the Standard Model and to look for physics beyond it,” says Vagnoni. “The first ever observation of CP violation in a baryon decay paves the way for further theoretical and experimental investigations of the nature of CP violation, potentially offering new constraints for physics beyond the Standard Model.”

The UMD members of the LHCb collaboration include professors Hassan Jawahery, Manuel Franco Sevilla and Phoebe Hamilton; postdoctoral associates Christos Hadjivasiliou, Lucas Meyer Garcia, and Parker Gardner; graduate research assistants Alex Fernez, Emily Jiang and Elizabeth Kowalczyk and undergraduate student Othello Gomes.

 “I congratulate the LHCb collaboration on this exciting result. It again underlines the scientific potential of the LHC and its experiments, offering a new tool with which to explore the matter–antimatter asymmetry in the Universe,” says CERN Director for Research and Computing, Joachim Mnich.