̽��ֱ�� of Cambridge - neutrino

New results deal a blow to the theoretical sterile neutrino

sc604 — Fri, 29 Oct 2021 08:58:21 +0000

̽��ֱ��results were gathered by an international team at the MicroBooNE experiment in the United States, with leadership from a UK team including researchers from the ̽��ֱ�� of Cambridge.

̽��ֱ��two most likely explanations for anomalies that were seen in two previous physics experiments: one which suggests a sterile neutrino, and one which points at limitations in those experiments, have been ruled out by MicroBooNE.

̽��ֱ��fourth neutrino

For more than two decades, this proposed fourth neutrino has remained a promising explanation for anomalies seen in earlier physics experiments. In these previous experiments, neutrinos were observed acting in a way not explained by the Standard Model of Physics – the leading theory to explain the building blocks of the universe and everything in it.

Neutrinos are the most abundant particle with mass in our universe, but they rarely interact with other matter, making them hard to study. But these elusive particles seem to hold answers to some of the biggest questions in physics – such as why the universe is made up of more matter than antimatter.

A 170-ton neutrino detector the size of a bus was created to study these particles – and became known as MicroBooNE. ̽��ֱ��international experiment has close to 200 collaborators from 36 institutions in five countries, and is supported by the Science and Technology Facilities Council (STFC) in the UK.

Standard Model holds up

̽��ֱ��team used cutting-edge technology to record precise 3D images of neutrino events and examine particle interactions in detail. Four complementary analyses released by the international MicroBooNE collaboration, at the Fermi National Accelerator Laboratory (Fermilab), deal a blow to the fourth neutrino hypothesis.

All four analyses show no sign of the sterile neutrino, and instead the results align with the Standard Model. ̽��ֱ��data is consistent with what the Standard Model predicts: three kinds of neutrinos only. But the anomalies are real and still need to be explained. Crucially, MicroBooNE has also ruled out the most likely explanation to explain these anomalies without requiring new physics.

These results mark a turning point in neutrino research. With the evidence for sterile neutrinos becoming weaker, scientists are investigating other possibilities for anomalies in perceived neutrino behaviour.

“This result is incredibly exciting as it suggests something far more interesting than we expected is happening – it’s now our goal to find out what this could be,” said Dr Melissa Uchida, who leads the Neutrino Group at Cambridge’s Cavendish Laboratory.

“This heralds the start of a new era of precision for neutrino physics, in which we will deepen our understanding of how the neutrino interacts, how it impacted the evolution of the universe, and what it can reveal to us about physics beyond our current Standard Model of how the universe behaves at the most fundamental level,” said Professor Justin Evans from the ̽��ֱ�� of Manchester, co-spokesperson of the experiment.

“Cambridge has played an integral part in this experiment both through the software — the reconstruction algorithms that allow us to distinguish particles and their interactions in MicroBooNE and through the analysis itself,” said Uchida. “With half the data still to analyse and more exotic avenues to pursue, there is an exciting journey ahead.”

̽��ֱ��UK at MicroBooNE

̽��ֱ��UK has taken a leading role in MicroBooNE, leading the development of state-of-the-art pattern recognition algorithms, making world-leading contributions to the understanding of neutrino interactions in the argon, and bringing a broad range of expertise to these searches for the elusive sterile neutrinos.

UK universities involved in MicroBooNE are Manchester, Edinburgh, Cambridge, Lancaster, Warwick and Oxford.

Mission to understand neutrinos

With our understanding of neutrinos still incomplete, the UK through STFC has invested in a science programme to address these key science questions, as well as invest in new technologies.

̽��ֱ��UK government has already invested £79 million in the Deep Underground Neutrino Experiment, Long-Baseline Neutrino Facility (LBNF), and the new PIP-II accelerator, all hosted by Fermilab.

This investment has given UK scientists and engineers the chance to take leading roles in the management and development of the DUNE far detector, the LBNF neutrino beam targetry and PIP-II accelerator.

Professor Mark Thomson, Executive Chair of STFC and one of the first UK physicists to join MicroBooNE, said: “This much-awaited result is a significant step our understanding of neutrinos. This extremely challenging measurement is also important in that the MicroBooNE experiment used a new technology to record detailed images of individual neutrino interactions.

“ ̽��ֱ��successful use the liquid argon imaging technology is a major stepping stone towards DUNE.

“Once complete by the end of this decade, DUNE will use several detectors each of the size of an extra-deep Olympic swimming pool, but with liquid argon replacing the water, to measure the movements and behaviours of neutrinos.”

Adapted from an STFC press release.

Results from a global science experiment have cast doubt on the existence of a theoretical particle beyond the Standard Model.

Cindy Arnold, Fermilab

Teams prepare to move the MicroBooNE cryostat from DZero to the Liquid Argon Test Facility (LArTF), USA.

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

Yes

UK researchers awarded £30m for global science project to better understand matter and antimatter

sc604 — Tue, 10 Dec 2019 06:33:43 +0000

̽��ֱ�� ̽��ֱ�� of Cambridge will provide essential contributions to the DUNE experiment, a global science project that brings the scientific community together to work on trying to answer some of the biggest questions in physics.

DUNE (the Deep Underground Neutrino Experiment) is hosted by the United States Department of Energy’s Fermilab, and will be designed and operated by a collaboration of over 1,000 physicists from 32 countries.

̽��ֱ��project aims to advance our understanding of the origin and structure of the universe. It will study the behaviour of particles called neutrinos and their antimatter counterparts, antineutrinos. This could provide insight as to why we live in a matter-dominated universe while anti-matter has largely disappeared.

“DUNE has the unique potential to answer fundamental questions that overlap particle physics, astrophysics, and cosmology,” said Professor Stefan Söldner-Rembold of the ̽��ֱ�� of Manchester, who leads the international DUNE collaboration as one of its spokespeople.

̽��ֱ��investment, from UK Research and Innovation’s Science and Technology Facilities Council (STFC), is a four-year construction grant to 13 educational institutions, and to STFC’s Rutherford Appleton and Daresbury Laboratories. This grant, of £30m, represents the first of two stages to support the DUNE construction project in the UK which will run until 2026 and represent a total investment of £45m.

Various elements of the experiment are under construction across the world, with the UK taking a major role in contributing essential expertise and components to the experiment and facility. UK scientists and engineers will design and produce the principle detector components at the core of the DUNE detector, which will comprise four large tanks each containing 17,000 kg of liquid argon.

̽��ֱ��UK groups are also developing a high-speed data acquisition system to record the signals from the detector, together with the sophisticated software needed to interpret the data and provide the answers to the scientific questions.

“DUNE could help to change the way we understand the universe,” said Dr Melissa Uchida, who leads the neutrino group at Cambridge’s Cavendish Laboratory. “This announcement has allowed the UK to take a leading role in many aspects of the experiment, making the UK the biggest DUNE contributor outside the USA. Our group will deliver hardware and software, as well as calibration and analysis effort for DUNE and we are ready and excited to meet the challenges ahead.”

DUNE will also watch for supernova neutrinos produced when a star explodes, which will allow the scientists to observe the formation of neutron stars and black holes and will investigate whether protons live forever or eventually decay, bringing us closer to fulfilling Einstein’s dream of a grand unified theory.

̽��ֱ��other UK universities involved in the project are Birmingham, Bristol, Edinburgh, Imperial College London, Lancaster, Liverpool, Manchester, Oxford, Sheffield, Sussex, UCL and Warwick.

Cambridge researchers will receive funding as part of a £30m investment in the DUNE experiment, which has the potential to lead to profound changes in our understanding of the universe.

CERN

Inside ProtoDUNE at CERN

Yes

Cambridge scientist leading UK’s £65m scientific collaboration with US

sc604 — Thu, 21 Sep 2017 15:59:58 +0000

This week, UK Universities and Science Minister Jo Johnson signed the agreement with the US Energy Department to invest the sum in the Long-Baseline Neutrino Facility (LBNF) and the Deep Underground Neutrino Experiment (DUNE). DUNE will study the properties of mysterious particles called neutrinos, which could help explain more about how the universe works and why matter exists at all.

This latest investment is part of a long history of UK research collaboration with the US, and is the first major project of the wider UK-US Science and Technology agreement.

On signing the agreement in Washington DC, UK Science Minister, Jo Johnson said: “Our continued collaboration with the US on science and innovation is beneficial to both of our nations and through this agreement we are sharing expertise to enhance our understanding of many important topics that have the potential to be world changing.

“ ̽��ֱ��UK is known as a nation of science and technical progress, with research and development being at the core of our industrial strategy. By working with our key allies, we are maintaining our position as a global leader in research for years to come.”

“ ̽��ֱ��international DUNE collaboration came together to realise a dream of a game-changing program of neutrino science; today’s announcement represents a major milestone in turning this dream into reality,” said Professor Thomson. “This UK investment in fundamental science will enable us to deliver critical systems to the DUNE experiment and to provide new opportunities for the next generation of scientists to work at the forefront of science and technology.”

This investment is a significant step which will secure future access for UK scientists to the international DUNE experiment. Investing in the next generation of detectors, like DUNE, helps the UK to maintain its world-leading position in science research and continue to develop skills in new cutting-edge technologies.

̽��ֱ��UK’s Science and Technology Facilities Council (STFC) will manage the UK’s investment in the international facility, giving UK scientists and engineers the chance to take a leading role in the management and development of the DUNE far detector and the LBNF beam line and associated PIP-II accelerator development.

Accompanying Jo Johnson on the visit to the US, Chief Executive Designate at UK Research and Innovation, Sir Mark Walport said: “Research and innovation are global endeavours. Agreements like the one signed today by the United Kingdom and the United States set the framework for the great discoveries of the future, whether that be furthering our understanding of neutrinos or improving the accessibility of museum collections.

“Agreements like this also send a clear signal that UK researchers are outward looking and ready to work with the best talent wherever that may be. UK Research and Innovation is looking forward to extending partnerships in science and innovation around the world.”

DUNE will be the first large-scale US-hosted experiment run as a truly international project at the inter-governmental level, with more than 1,000 scientists and engineers from 31 countries building and operating the facility, including many from the UK. ̽��ֱ��US is meeting the major civil construction costs for conventional facilities, but is seeking international partners to design and build major elements of the accelerator and detectors. ̽��ֱ��total international partner contributions to the entire project are expected to be about $500M.

̽��ֱ��UK research community is already a major contributor to the DUNE collaboration, with 14 UK universities and two STFC laboratories providing essential expertise and components to the experiment and facility. This ranges from the high-power neutrino production target, the readout planes and data acquisitions systems to the reconstruction software.

Dr Brian Bowsher, Chief Executive of STFC, said:“This investment is a significant and exciting step for the UK that builds on UK expertise.

“International partnerships are the key to building these world-leading experiments, and the UK’s continued collaboration with the US, through STFC, demonstrates that we are the science partner of choice in such agreements.

“I am looking forward to seeing our scientists work with our colleagues in the US in developing this experiment and the exciting science which will happen as a result.”

One aspect DUNE scientists will look for is the differences in behaviour between neutrinos and their antimatter counterparts, antineutrinos, which could give us clues as to why we live in a matter-dominated universe – in other words, why we are all here, instead of having been annihilated just after the Big Bang. DUNE will also watch for neutrinos produced when a star explodes, which could reveal the formation of neutron stars and black holes, and will investigate whether protons live forever or eventually decay, bringing us closer to fulfilling Einstein’s dream of a grand unified theory.

̽��ֱ��DUNE experiment will attract students and young scientists from around the world, helping to foster the next generation of leaders in the field and to maintain the highly skilled scientific workforce worldwide.

̽��ֱ��Cambridge team is playing a leading role in the development of the advanced pattern recognition and computational techniques that will be needed to interpret the data from the vast DUNE detectors.

Other than Cambridge, the UK universities involved in the project are Birmingham, Bristol, Durham, Edinburgh, Imperial, Lancaster, Liverpool, UCL, Manchester, Oxford, Sheffield, Sussex and Warwick.

Adapted from an STFC press release.

̽��ֱ��UK is investing £65 million in a flagship global science project based in the United States that could change our understanding of the universe, securing the UK’s position as the international research partner of choice. Professor Mark Thomson from the ̽��ֱ�� of Cambridge’s Cavendish Laboratory has been the elected co-leader of the international DUNE collaboration since its inception and is the overall scientific lead of this new UK initiative.

This UK investment in fundamental science will enable us to deliver critical systems to the DUNE experiment and to provide new opportunities for the next generation of scientists to work at the forefront of science and technology.

Mark Thomson

MicroBooNE

Neutrino event in liquid argon

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

Yes

First evidence of ‘ghost particles’

sc604 — Mon, 02 Nov 2015 16:55:43 +0000

An international team of scientists at the MicroBooNE physics experiment in the US, including researchers from the ̽��ֱ�� of Cambridge, detected their first neutrino candidates, which are also known as 'ghost particles'. It represents a milestone for the project, involving years of hard work and a 40-foot-long particle detector that is filled with 170 tons of liquid argon.

Neutrinos are subatomic, almost weightless particles that only interact via gravity or nuclear decay. Because they don’t interact with light, they can’t be seen. Neutrinos carry no electric charge and travel through the universe almost entirely unaffected by natural forces. They are considered a fundamental building block of matter. ̽��ֱ��2015 Nobel Prize in physics was awarded for neutrino oscillations, a phenomenon that is of great important to the field of elementary particle physics.

“It’s nine years since we proposed, designed, built, assembled and commissioned this experiment,” said Bonnie Fleming, MicroBooNE co-spokesperson and a professor of physics at Yale ̽��ֱ��. “That kind of investment makes seeing first neutrinos incredible.”

Following a 13-week shutdown for maintenance, Fermilab’s accelerator complex near Chicago delivered a proton beam on Thursday, which is used to make the neutrinos, to the laboratory’s experiments. After the beam was turned on, scientists analysed the data recorded by MicroBooNE’s particle detector to find evidence of its first neutrino interactions.

Scientists at the ̽��ֱ�� of Cambridge have been working on advanced image reconstruction techniques that contributed to the ability to identify the rare neutrino interactions in the MicroBooNE data.

̽��ֱ��MicroBooNE experiment aims to study how neutrinos interact and change within a distance of 500 meters. ̽��ֱ��detector will help scientists reconstruct the results of neutrino collisions as finely detailed, three-dimensional images. MicroBooNE findings also will be relevant for the forthcoming Deep Underground Neutrino Experiment (DUNE), which will examine neutrino transitions over longer distances.

“Future neutrino experiments will use this technology,” said Sam Zeller, Fermilab physicist and MicroBooNE co-spokesperson. “We’re learning a lot from this detector. It’s important not just for us, but for the whole physics community.”

“This is an important step towards the much larger Deep Underground Neutrino Experiment (DUNE)”, said Professor Mark Thomson of Cambridge’s Cavendish Laboratory, co-spokesperson of the DUNE collaboration and member of MicroBooNE. “It is the first time that fully automated pattern recognition software has been used to identify neutrino interactions from the complex images in a detector such as MicroBooNE and the proposed DUNE detector.”

Adapted from a Fermilab press release.

Major international collaboration has seen its first neutrinos – so-called ‘ghost particles’ – in the experiment’s newly built detector.

This is an important step towards the much larger Deep Underground Neutrino Experiment (DUNE)

Mark Thomson

MicroBooNE

A neutrino event candidate in the MicroBooNE detector

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

Yes