Physicists believe they have solved proton size mystery

Recent studies have focused on the measurement of the proton’s radius, which has caused confusion in the scientific community. Several experiments have produced different results over the years. In 2010, an international team reported a value of 0.84 femtometers. This measurement led to a discrepancy in the understanding of the proton’s size, which is important in physics.

In 2013, the same team confirmed their finding through muon-based experiments, producing a similar measurement. Researchers later conducted a 2016 experiment with a heavier hydrogen isotope, which also supported the 2010 result. However, studies in 2017 and 2018 using regular hydrogen showed mixed results. The 2017 study matched the 2010 value, while the 2018 measurement suggested a larger size.

In 2019, scientists from York University aimed to clarify the conflicting results. They measured the proton’s radius using electrons and found a value of 0.833 femtometers, again aligning with the earlier finding.

Most recently, two studies used advanced techniques in vacuum chambers with lasers to examine hydrogen atoms. These studies confirmed that the proton has a radius of about 0.84 femtometers, consistent with the original 2010 measurement. As physicist Juan Rojo noted, the proton radius should be a universal property, and these papers provide different methods to reach the same conclusion.

How much do you know?

What value of the proton's radius did the international team report in 2010?

0.84 femtometers

0.833 femtometers

0.85 femtometers

0.8 femtometers

In what year did researchers conduct an experiment with a heavier hydrogen isotope?

2010

2013

2016

2018

What was the result of the 2018 measurement regarding the proton's radius?

It matched the 2010 value

It suggested a larger size

It was inconclusive

It confirmed the 2016 finding

Which university conducted research in 2019 to clarify conflicting results about the proton's radius?

Harvard University

Oxford University

York University

Stanford University

According to recent studies, what is the proton's radius confirmed to be?

0.84 femtometers

0.85 femtometers

0.82 femtometers

0.83 femtometers

What measurement technique did the most recent two studies use to examine hydrogen atoms?

Microscopy

Vacuum chambers with lasers

Ultrasound

Magnetic resonance

The 2010 measurement of the proton's radius was later adjusted in subsequent years.

True False

The measurements from 2017 and 2018 were consistent with each other.

True False

All experiments conducted from 2010 to 2019 produced different results.

True False

The measurement of 0.833 femtometers was reported by scientists from York University.

True False

Juan Rojo stated that the proton radius should be a variable property.

True False

The proton radius measurements have shown an overall agreement with the original findings.

True False

In 2010, an international team reported a proton radius value of femtometers.

The 2016 experiment used a heavier hydrogen isotope to support the result.

The 2018 measurement suggested a size compared to the earlier findings.

The 2019 measurements from York University aligned with the earlier finding of femtometers.

The recent studies used advanced techniques in vacuum chambers with to confirm the proton's radius.

Most measurements confirmed that the proton has a radius of about femtometers.

This question is required