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3 weeks ago | 
home.cern | Ana M. Lopes
The LHCb experiment has taken a leap in precision physics at the Large Hadron Collider (LHC). In a new paper submitted to Physical Review Letters, the LHCb collaboration reports the first dedicated measurement of the Z boson mass at the LHC, using data from high-energy collisions between protons recorded in 2016 during the collider’s second run. The Z boson is a massive, electrically neutral particle that mediates the weak nuclear force – one of nature’s fundamental forces.
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1 month ago | 
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Have you ever wondered what it would be like to build a brand new world on an exoplanet? Students have the opportunity to do exactly that with IdeaSquare Planet (i2Planet), a novel teaching methodology designed to encourage creativity and foster the development of systems. IdeaSquare, the innovation space at CERN, has developed the i2Planet programme in connection with the UN Sustainable Development Goals. It starts off with students partaking in a scenario in which humans have to establish their existence on a new “planet Y”. The students, who have been split into interdisciplinary teams, have to solve specific challenges for their settlements. The second half of the programme brings them back to our home planet, where the teams apply their ideas to a real-world context, focusing on current challenges, such as droughts and accessible healthcare. The goal is purely educational: preparing students for their future roles as changemakers. Through the programme, the students are equipped with the skills to tackle complex challenges under high uncertainty, make informed decisions and assumptions and develop fast and complex decision-making skills. With 255 students having taken part in 13 pilot programmes over the last two years, i2Planet is now a flagship programme at IdeaSquare. In this period, students were able to come up with innovative ideas to address current challenges. For example, an interdisciplinary team made up of engineers, lawyers, designers, physicists, business managers and many others had an innovative idea to tackle plastic pollution: cultivating plastic-eating bacteria to get rid of plastic waste. During the pilot programme, sustainability was not the only issue considered by the students who took part. Other teams had original proposals on how to deal with law enforcement and how to provide clean water, preventing droughts by humidifying the ecosystem using lianas. I2Planet is open to universities across Europe and beyond and is designed for students at master’s level. If you are an educator interested in participating in the programme, please contact [email protected].
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2 months ago | 
home.cern | Naomi Dinmore
Quantum entanglement is a fascinating phenomenon where two particles’ states are tied to each other, no matter how far apart the particles are. In 2022, the Nobel Prize in Physics was awarded to Alain Aspect, John F. Clauser and Anton Zeilinger for groundbreaking experiments involving entangled photons. These experiments confirmed the predictions for the manifestation of entanglement that had been made by the late CERN theorist John Bell.
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Mar 28, 2025 | 
home.cern | Alex Epshtein
In late 2023, Wojciech Brylinski was analysing data from the NA61/SHINE collaboration at CERN for his thesis when he noticed an unexpected anomaly – a strikingly large imbalance between charged and neutral kaons in argon–scandium collisions. He found that, instead of being produced in roughly equal numbers, charged kaons were produced 18.4% more often than neutral kaons.
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Feb 5, 2025 | 
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During the inauguration of the International Year of Quantum Science and Technology on 4 February, Simona-Mirela Miculescu, President of the 42nd session of the General Conference of UNESCO, mentioned CERN in her opening remarks as an example of science diplomacy and international collaboration. (Image: Alexia Yiannouli/CERN) The United Nations has declared 2025 the International Year of Quantum Science and Technology (IYQ). Kicking off about 100 planned events worldwide was an opening ceremony on 4 February at the UNESCO headquarters in Paris. Enrica Porcari, Head of CERN’s Information Technology department, attended the opening ceremony: “What matters is how much the planned initiatives will move the needle towards a broader public awareness about the profound implications that quantum science and technology already have and, most importantly, will soon have on society.” The CERN-based Open Quantum Institute (OQI) is a participating partner in the IYQ and a leading project coordinator for key events around Geneva throughout the year. Quantum is also the central theme for CERN’s 2025 public events season in CERN Science Gateway, supported by the CERN & Society Foundation. The public events season begins with De Temps en Temps on 11 February, the International Day of Women and Girls in Science. Physicist Yasmine Amhis from the LHCb experiment and the DoniSSi string quartet invite you to explore the mysteries of time in all its facets. Find out more and register here: https://indico.cern.ch/e/detempsentemps and discover the full programme here: https://visit.cern/events.
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Dec 4, 2024 | 
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In a paper published today in the journal Nature, the CLOUD collaboration at CERN reveals a new source of atmospheric aerosol particles that could help scientists to refine climate models. Aerosols are microscopic particles suspended in the atmosphere that arise from both natural sources and human activities. They play an important role in Earth’s climate system because they seed clouds and influence their reflectivity and coverage. Most aerosols arise from the spontaneous condensation of molecules that are present in the atmosphere only in minute concentrations. However, the vapours responsible for their formation are not well understood, particularly in the remote upper troposphere. The CLOUD (Cosmics Leaving Outdoor Droplets) experiment at CERN is designed to investigate the formation and growth of atmospheric aerosol particles in a controlled laboratory environment. CLOUD comprises a 26 m3 ultra-clean chamber and a suite of advanced instruments that continuously analyse its contents. The chamber contains a precisely selected mixture of gases under atmospheric conditions, into which secondary beams of charged pions are fired from CERN’s Proton Synchrotron to mimic the influence of galactic cosmic rays. “High concentrations of aerosol particles have been observed high over the Amazon rainforest for the past twenty years, but their source has remained a puzzle until now,” says CLOUD spokesperson Jasper Kirkby. “Our latest study shows that the source is isoprene emitted by the rainforest and lofted in deep convective clouds to high altitudes, where it is oxidised to form highly condensable vapours. Isoprene represents a vast source of biogenic particles in both the present-day and pre-industrial atmospheres that is currently missing in atmospheric chemistry and climate models.” Isoprene is a hydrocarbon containing five carbon atoms and eight hydrogen atoms. It is emitted by broad-leaved trees and other vegetation and is the most abundant non-methane hydrocarbon released into the atmosphere. Until now, isoprene’s ability to form new particles has been considered negligible. The CLOUD results change this picture. By studying the reaction of hydroxyl radicals with isoprene at upper tropospheric temperatures of −30 °C and −50 °C, the collaboration discovered that isoprene oxidation products form copious particles at ambient isoprene concentrations. This new source of aerosol particles does not require any additional vapours. However, when minute concentrations of sulphuric acid or iodine oxoacids were introduced into the CLOUD chamber, a 100-fold increase in the aerosol formation rate was observed. Although sulphuric acid derives mainly from anthropogenic sulphur dioxide emissions, the acid concentrations used in CLOUD can also arise from natural sources. In addition, the team found that isoprene oxidation products drive rapid growth of particles to sizes at which they can seed clouds and influence the climate – a behaviour that persists in the presence of nitrogen oxides produced by lightning at upper-tropospheric concentrations. After continued growth and descent to lower altitudes, these particles may provide a globally important source for seeding shallow continental and marine clouds, which influence Earth’s radiative balance (the amount of incoming solar radiation compared to outgoing longwave radiation). “This new source of biogenic particles in the upper troposphere may impact estimates of Earth's climate sensitivity, since it implies that more aerosol particles were produced in the pristine pre-industrial atmosphere than previously thought,” adds Kirkby. “However, until our findings have been evaluated in global climate models, it’s not possible to quantify the effect.” The CLOUD findings are consistent with aircraft observations over the Amazon, as reported in an accompanying paper in the same issue of Nature. Together, the two papers provide a compelling picture of the importance of isoprene-driven aerosol formation and its relevance for the atmosphere. Since it began operation in 2009, the CLOUD experiment has unearthed several mechanisms by which aerosol particles form and grow in different regions of Earth’s atmosphere. “In addition to helping climate researchers to understand the critical role of aerosols in Earth’s climate, the new CLOUD result demonstrates the rich diversity of CERN’s scientific programme and the power of accelerator-based science to address societal challenges,” says CERN Director for Research and Computing, Joachim Mnich. Isoprene from forests is efficiently transported at night by deep convective clouds into the upper troposphere. During daylight, the isoprene that has accumulated overnight, together with daytime-convected isoprene, reacts with hydroxyl radicals and NOx from lightning to produce oxygenated isoprene organic molecules. These combine with trace amounts of acids to produce high particle concentrations at temperatures below −30 °C. The newly formed particles grow rapidly over several hours and days while following the descending air masses. This mechanism may provide an extensive source of cloud condensation nuclei for shallow continental and marine clouds, which influence Earth’s radiative balance. Further material: Infographic Photo collection Video collection
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Nov 28, 2024 | 
home.cern | Fabiola Gianotti
Geneva, 28 November 2024. CERN, in partnership with the Republic and Canton of Geneva and the City of Geneva, announces the launch of the Resonance residency programme. Artists who are based in Geneva and interested in science and technology are invited to apply. The Resonance residency is a unique opportunity for an artist to embark on a fully funded two-month residency at CERN in 2025.
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Nov 6, 2024 | 
home.cern | Fabiola Gianotti
At the beginning of the year, in order to make our ethics-related framework more easily accessible, the HR department grouped all the relevant information and resources under a single point of reference at https://hr.web.cern.ch/ethics. To go further and ensure that every CERN staff member is aware of the guidelines of our ethical framework, the HR department has developed an e-learning course titled “Ethics at CERN”, now available in English and French on the CERN Learning Hub.
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Nov 6, 2024 | 
home.cern | Fabiola Gianotti
Voir en français Help protect yourself and others on the road by making visibility a priority As winter approaches, shorter days and bad weather mean reduced visibility for everyone on the road. Whether you're cycling, walking or driving, it’s crucial to remember the principle of "see and be seen". It isn’t just about looking out for yourself; it’s about respecting and being mindful of all road users, ensuring that everyone reaches their destination safely.
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Nov 6, 2024 | 
home.cern | Fabiola Gianotti
Check out this curated list of upcoming events for the CERN community 11–15 Nov | Physics | 4/3-006 | TH Institute | EN Light ion collisions at the LHC bringing together theorists, experimentalists and accelerator physicists 19 Nov 14:00 | At CERN | Main Auditorium | LGBTQ+@CERN | EN LGBTQ+ in STEM Day – Colloquium and Cupcakes 21 Nov 14:00 | Knowledge Sharing | CERN Library | Archives, Library and Open Science events | EN The Voice of Science – Meet Dr Claire Malone 6 Dec 13:30 | Knowledge...