(Press-News.org) Researchers from the KATRIN (Karlsruhe Tritium Neutrino) experiment report the most precise measurement of the upper mass limit of the neutrino to date, establishing it as 0.45 electron volts (eV) – less than one-millionth the mass of an electron. The findings tighten the constraints on one of the universe’s most elusive fundamental particles and push the boundaries of physics beyond the Standard Model. Neutrinos – electrically neutral elementary particles – are the most abundant particles in the universe and exist as three distinct types or “flavors”: electron neutrino, muon neutrino, and tau neutrino. These flavors oscillate, meaning a single neutron can transform into each type as it travels, providing compelling evidence that neutrinos possess mass that contradicts the Standard Model’s original assumption of massless neutrinos. However, their exact mass remains one of the great mysteries of particle physics. Here, Max Aker and the KATRIN Collaboration present the results of the first five measurement campaigns of the KATRIN experiment. The KATRIN experiment determines the neutrino’s mass by analyzing the beta decay of tritium. During this decay, a neutron transforms into a proton, emitting both an electron and an electron antineutrino – the latter being the neutrino’s antiparticle. By analyzing the distribution of total decay energy between the emitted electron and the electron antineutrino, the neutrino’s mass can be inferred. Over 259 days between 2019 and 2021, the KATRIN Collaboration measured the energy of approximately 36 million electrons – a dataset six times larger than previous runs. The findings establish the most stringent laboratory-based upper limit on the effective electron neutrino mass, placing it at < 0.45 eV with a 90% confidence level. This result marks the third refinement of the neutrino mass limit and improves upon the previous limit by a factor of 2. “The neutrino mass measuring campaign of the KATRIN experiment will end in 2025 after reaching 1000 days of data acquisition,” writes Loredana Gastaldo in a related Perspective. “Analysis of the full data set gained from this grand project will allow for estimating the effective electron neutrino mass close to the projected value of 0.3 eV at 90% confidence level.”
END
KATRIN experiment sets most precise upper limit on neutrino mass: 0.45 eV
Summary author: Walter Beckwith
2025-04-10
ELSE PRESS RELEASES FROM THIS DATE:
How the cerebellum controls tongue movements to grab food
2025-04-10
By studying the skilled movements of marmoset tongues, researchers have discovered that Purkinje cells (P-cells) in a brain region called the cerebellum signal to stop protrusion as the tongue approaches its target, according to a study published April 10th in the open-access journal PLOS Biology by Reza Shadmehr from Johns Hopkins School of Medicine, U.S., and colleagues.
We use our tongue to shape the air and generate sounds to communicate, and we use our tongue to evaluate food morsels and transport them through the oral cavity when eating. These skillful acts involve coordination of more ...
It’s not you—it’s cancer
2025-04-10
Cancer ravages both body and mind. If you’ve ever lost loved ones to the disease, you might recognize the physical and emotional changes cancer patients often endure during their final months. They seem drained of strength and spirit. Even people who’ve maintained a positive outlook throughout their lives can enter a state of despair. New research published in Science suggests apathy and lack of motivation are symptoms of a condition called cancer cachexia. Cold Spring Harbor Laboratory ...
Drug pollution alters migration behavior in salmon
2025-04-10
In the largest study of its kind to date, a team of international researchers has investigated how pharmaceutical pollution affects the behaviour and migration of Atlantic salmon.
The study, led by the Swedish University of Agricultural Sciences, revealed that commonly detected environmental levels of clobazam – a medication often prescribed for sleep disorders – increased the river-to-sea migration success of juvenile salmon in the wild.
The researchers also discovered that clobazam shortened the time it took for juvenile salmon to navigate through two hydropower dams along their migration route – obstacles that typically ...
Scientists decode citrus greening resistance and develop AI-assisted treatment
2025-04-10
In a groundbreaking study published in Science, a research team led by Prof. YE Jian from the Institute of Microbiology of the Chinese Academy of Sciences has identified the first mechanism of citrus resistance to citrus greening disease, or huanglongbing (HLB).
Utilizing artificial intelligence (AI), the team has also developed antimicrobial peptides that offer a promising therapeutic approach to combat the disease. This discovery addresses a long-standing challenge in the agricultural community—the absence of naturally occurring HLB-resistant genes in citrus.
Citrus ...
Venom characteristics of a deadly snake can be predicted from local climate
2025-04-10
Local climate can be used to predict the venom characteristics of a deadly snake that is widespread in India, helping clinicians to provide targeted therapies for snake bite victims, according to a study publishing April 10 in the open-access journal PLOS Neglected Tropical Diseases by Kartik Sunagar and colleagues at the Indian Institute of Science.
Russell’s viper (Daboia russelii) is found across the Indian subcontinent and is responsible for over 40% of snake ...
Brain pathway links inflammation to loss of motivation, energy in advanced cancer
2025-04-10
The fatigue and lack of motivation that many cancer patients experience near the end of life have been seen as the unavoidable consequences of their declining physical health and extreme weight loss. But new research from Washington University School of Medicine in St. Louis challenges that long-held assumption, showing instead that these behavioral changes stem from specific inflammation-sensing neurons in the brain.
In a study published April 11 in Science, the researchers report that they identified a direct connection between cancer-related inflammation ...
Researchers discover large dormant virus can be reactivated in model green alga
2025-04-10
Researchers had been studying the green alga Chlamydomonas reinhardtii for decades without seeing evidence of an active virus within it — until a pair of Virginia Tech researchers waded into the conversation.
Maria Paula Erazo-Garcia and Frank Aylward not only found a virus in the alga but discovered the largest one ever recorded with a latent infection cycle, meaning it goes dormant in the host before being reactivated to cause disease.
“We’ve known about latent infections for a long time,” said Aylward, associate professor in the Department of Biological Sciences. ...
New phase of the immune response uncovered
2025-04-10
The research groups led by Wolfgang Kastenmüller and Georg Gasteiger employed innovative microscopy techniques to observe how specific immune cells, known as T-cells, are activated and proliferate during a viral infection. Their findings revealed novel mechanisms: the immune system amplifies its defense cells in a far more targeted way than previously believed.
T-Cells Proliferate and Specialize During the Immune Response
T-cells are crucial defense cells in the immune system. To effectively ...
Drawing board rather than salt shaker
2025-04-10
Bioinformaticians from Heinrich Heine University Düsseldorf (HHU) and the university in Linköping (Sweden) have established that the genes in bacterial genomes are arranged in a meaningful order. In the renowned scientific journal Science, they describe that the genes are arranged by function: If they become increasingly important at faster growth, they are located near the origin of DNA replication. Accordingly, their position influences how their activity changes with the growth rate.
Are genes distributed randomly along the bacterial chromosome, as if scattered from a salt shaker? This opinion, which is held by a majority of researchers, has ...
Engineering invites submissions on AI for engineering
2025-04-10
Artificial intelligence (AI) is playing an increasingly pivotal role in revolutionizing the field of engineering, triggering a new era of technological and industrial evolution. A series of recent breakthroughs in areas like natural language processing, computer vision, and machine learning, with the Nobel Prize-winning work in artificial neural networks and protein structure prediction serving as prime examples, have effectively bridged the gap between the physical and digital worlds. The emergence of general AI technologies, especially large language models, has given rise ...
LAST 30 PRESS RELEASES:
Parents with alcohol-related diagnoses are twice as likely to maltreat children
Giant croclike carnivore fossils found in the Caribbean
Palatable versus poisonous: Eavesdropping bats must learn to identify which prey is safe to eat
Being hit by an SUV increases the likelihood of death or serious injury, new research shows
New test diagnoses bacterial meningitis faster and better
Majority of Americans experience some form of gun violence in person
Broader antibiotic use could change the course of cholera outbreaks, research suggests
Higher cigarette taxes may improve childhood survival
Exercise can counter detrimental effects of cancer treatment
Too few ward nurses linked to longer hospital stay, readmission, and risk of death
Friendship bracelet: New technology connects neurodiverse groups of children
Forest in sync: Spruce trees communicate during a solar eclipse
Parents take a year to ‘tune in’ to their child’s feelings about starting school, research suggests
American Heart Association stands together with Arkansas and against the soda industry to reduce sugary drink consumption
AI-ECG tools can help clinicians identify heart issues early in women planning to have children
NIH’s initiative to prioritize human-based research a ‘big win for animals,’ says doctors group
Nearly one-quarter of e-Scooter injuries involved substance impaired riders
Age, previous sports experience, stronger predictors of performance in children than previous concussions, York U study finds
Dogs with meningiomas live longer with radiation therapy than surgery, Texas A&M researchers find
Pregnancy-related proteins in tumors linked to worse survival in female lung cancer patients
New study highlights success of financial toxicity tumor board in reducing cancer treatment costs
CAD/CAM shows clinical benefits in jaw reconstruction, reports Plastic and Reconstructive Surgery
Missed school is an overlooked consequence of climate change
Reasons why anxiety and depression promote low self-belief revealed
UMass Amherst graduate student’s discovery shows that even neutral molecules take sides when it comes to biochemistry
Electroactive biofiltration dynamic membrane: A new hope for wastewater treatment
Disparities in breast reconstruction persist after ACA, reports Plastic and Reconstructive Surgery
Making magnetic biomaterials
Synchrotron in a closet: Bringing powerful 3D X-ray microscopy to smaller labs
Multiscale fibrous reinforcements yield high-performance construction composite
[Press-News.org] KATRIN experiment sets most precise upper limit on neutrino mass: 0.45 eVSummary author: Walter Beckwith