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Topological fluids, the proton radius and art and science: the June 2021 issue of Physics World magazine is now out

01 Jun 2021 Matin Durrani

The June 2021 issue of Physics World includes a look at questions in physics that are taking a long time to solve

The June 2021 issue of Physics World magazine

Whether it’s the existence of the Higgs boson, dark matter or gravitational waves, some questions in physics just take an extraordinarily long time to settle. I’m sure you can think of your own examples, but the June 2021 issue of Physics World magazine looks at two particularly long-standing questions in physics.

First, Robert Crease summarizes the history of muon “g–2” experiments, which seek to measure g – the ratio of this particle’s magnetic moment to its spin. If g isn’t exactly 2, that could be a hint of “new physics”, yet despite five different versions of these experiments over the last 60 years, we’re still not sure.

Also in the issue, Edwin Cartlidge examines our attempts to measure the radius of the proton, which was traditionally done either by scattering electrons off it or carrying out spectroscopy of the hydrogen atom. An official value was first agreed in 2002, but a decade later, a new and more precise spectroscopy experiment on the muon found a proton radius 4% lower expected.

Quite why physicists settled on the lower value is the theme of the article. As the feature makes clear, it’s a messy process with various physicists redoing and refining experiments, arguing their case, and – ultimately – voting on the matter.

If you’re a member of the Institute of Physics, you can read the whole of Physics World magazine every month via our digital apps for iOSAndroid and Web browsers. Let us know what you think about the issue on TwitterFacebook or by e-mailing us at pwld@ioppublishing.org.

For the record, here’s a run-down of what else is in the issue.

• Publishers announce name-change policies – The introduction of trans-inclusive journal policies has been broadly welcomed, but some say that more needs to be done, as Juanita Bawagan reports

• Imposter intuition – Chanda Prescod-Weinstein explains that intuition in physics can be a social construct, one that is culturally embedded about who is normal and what is intuitive

• Towards a new equality narrative – Elizabeth Crilly, Alison Voice and Samantha Pugh say valuing and recognizing other sources of technical knowledge – rather than just pure scientific competence – can help to encourage more people from under-represented groups into physics

• Nothing ventured… – In the first of a series of articles about how to start and fund a fledgling business, James McKenzie examines the art of securing money from venture capitalists

• Muons and streetlights – Robert P Crease explains why the new measurement of “g–2” was just the latest in a series of such experiments that stretches back more than 60 years

• It’s topology, naturally – One of the hottest topics in solid-state physics is having a fluid makeover. As Jon Cartwright reports, the consequences of topological behaviours in fluid dynamics could be far-reaching for our understanding of the natural world and other complex systems, such as fusion tokamaks

• What does physics look like, and does it matter? – The conceptual worlds of physics have long inspired artists and thinkers across disciplines. Anna Starkey explores how different approaches to visualizing physics can open up the way that society thinks and feels about physics as an imaginative human endeavour

• Solving the proton puzzle – Why were so many physicists so wrong about the size of the proton for so long? As Edwin Cartlidge explains, the solution to this “proton radius puzzle” has as much to do with bureaucracy and politics as it does with physics

• Light at the end of the tunnel – David Appell reviews Lightspeed: the Ghostly Aether and the Race to Measure the Speed of Light by John Spence

• Learning from the impossible – Philip Ball reviews The Science of Can and Can’t by Chiara Marletto

• Reaching out to the stars – Luz Ángela García, a cosmology postdoc in Bogotá, Colombia, talks to Rob Lea about her journey into physics and astronomy as a woman from South America

• Ask me anything: Jim Al-Khalili – Careers advice from the physicist, communicator and broadcaster.

• A funny thing happened on my way to class – Joanne O’Meara on bringing humour to teaching.

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