Tag Archives: Proton

Revealing Proton Size: New Insights into the Fundamental Particle

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Vacuum chamber used to measure electronic transitions in atomic hydrogen, aiding in estimating proton size.

Axel Beyer/MPQ

Newly acquired data reveals the true size of the proton, marking a significant milestone in particle physics. Over 15 years ago, a surprising experiment reshaped our understanding of this subatomic particle’s fundamental properties.

Protons are essential constituents of matter, and until 2010, our comprehension of their structure seemed complete. We recognized that protons consist of three quarks, but uncertainties about their size lingered.

Recent investigations involving exotic hydrogen atoms suggest that protons may actually be 4% smaller than previously thought. Research teams are now tirelessly exploring sources of error and theories that might illuminate the proton radius puzzle. In 2019, an additional experiment reinforced indications that the proton’s size had been overestimated.

Excitingly, the confusion surrounding proton size appears to be resolved through two complementary experiments, which convincingly support the idea of smaller protons. Their findings indicate that the proton’s radius is approximately 0.84 femtometers—an astonishing measurement, less than one millionth of a meter.

As physicist Dylan Yost from Colorado State University explains, “Reviewing the data makes you reconsider the betting odds on the proton’s radius. These measurements significantly bolster our understanding.”

To ascertain this new radius, both research teams focused their efforts on hydrogen atoms, which consist of one proton and one electron. The electromagnetic interaction between these oppositely charged particles is influenced by the proton’s size, allowing researchers to deduce its dimensions by observing electron energy transitions.

Using lasers, the teams manipulated electrons in hydrogen atoms, measuring three previously unrecorded energy transitions.

The calculated proton radius not only aligned with each other but also confirmed the crucial 2010 measurements. As physicist Lothar Meisenbacher from the University of California, Berkeley noted, “It’s extremely unlikely that this proton radius puzzle persists.”

Conducting these experiments was no small feat. The teams placed hydrogen atoms in complete vacuum environments, utilized expensive lasers, and meticulously calibrated their equipment. While data collection might take weeks, it often requires years to eliminate potential disturbances and errors, according to Meisenbacher.

Yet, if multiple experiments produce comparable results, diversity in methodologies can serve as an advantage, ensuring that equipment-specific errors do not skew findings. Juan Rojo from Vrije Universiteit Amsterdam emphasizes that “the proton’s radius is a universal property, and consistent results across different approaches enhance credibility.”

Understanding proton size is vital for refining theories about potential new particles, as noted by Yost. The recent MPQ experiment has accurately tested existing theories, such as quantum electrodynamics, with a precision of 0.5 parts per million. Although no discrepancies with predicted outcomes emerged, the research lays the groundwork for future explorations in particle physics.

While high-energy colliders seek heavier particles, these precise hydrogen atom studies interrogate for lighter, hidden particles. “With a clearer understanding of proton size, we can now ask, what constraints can we establish for new physics?” concludes Yost.

Topics:

  • particle physics/
  • quantum physics

Source: www.newscientist.com

CERN Physicists Uncover Heavier Proton Relative in Groundbreaking Discovery

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CERN’s Large Hadron Collider (LHC) physicists, through the LHCb experiment, have unveiled a groundbreaking deuteron-like particle known as Ξcc⁺. This remarkable particle, composed of two charm quarks and one down quark, offers scientists a novel means to explore the formidable forces binding the fundamental constituents of matter.

Artist’s impression of the double charm baryon Ξcc⁺ containing two charm quarks and one down quark. Image credit: CERN.

Quarks, the fundamental building blocks of matter, exist in six distinct flavors: up, down, charm, strange, top, and bottom.

Typically, quarks combine in pairs or groups of three to form mesons and baryons. While protons are stable, most hadrons (mesons and baryons) are fleeting, vanishing almost immediately upon creation, making detection a challenge.

To facilitate their production, high-energy particles are collided within machines like the LHC.

These unstable hadrons decay rapidly, yet the resultant more stable particles can be detected, enabling scientists to infer the properties of the original particles.

With this discovery, the total count of hadrons identified in LHC experiments has risen to 80.

“This marks the first new particle identified following the LHCb detector upgrades completed in 2023, and it is the second baryon discovered that features two heavy quarks, echoing the initial observation made nearly a decade ago,” stated LHCb spokesperson Dr. Vincenzo Vagnoni.

“The implications of this result will aid theorists in testing quantum chromodynamics models, enhancing our understanding of strong forces that unify quarks to form conventional baryons and mesons, as well as more exotic structures like tetraquarks and pentaquarks.”

In 2017, the LHCb team reported a similar particle containing two charm quarks and an up quark, which differs from the newly discovered particle solely by having a down quark.

Despite their similarities, the predicted lifetimes for the new particles are up to six times shorter than their counterparts due to intricate quantum effects, complicating their observation.

By scrutinizing data from proton-proton collisions captured by the LHCb detector during the LHC’s third operation phase, physicists confirmed a new baryon with a statistical significance of 7 sigma, surpassing the 5 sigma threshold needed for a discovery claim.

“This significant milestone exemplifies how LHCb’s unique capabilities contribute to its success,” remarked CERN Director-General Mark Thomson.

“This highlights the direct link between experimental upgrades at CERN and the new discoveries, paving the way for the pioneering science anticipated from the High-Luminosity LHC.”

“These accomplishments were made possible due to the extraordinary performance of CERN’s accelerator complex and the unwavering commitment of the scientists involved in the LHCb experiment.”

Source: www.sci.news

Scientists uncover mysteries of quantum entanglement in proton particles

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Physicists have discovered a new way to look inside protons using data from smashups of high-energy particles. Their approach uses quantum information science to map how the tracking of particles flowing from electron-proton collisions is affected by quantum entanglement inside the protons. As a result, it became clear that quarks and gluons, the basic building blocks of the proton’s structure, are affected by so-called quantum entanglement.

Data from past proton-electron collisions provide strong evidence that proton quarks and gluon oceans are entangled, which plays a key role in strong force interactions. There is a possibility that there are. Image credit: Valerie Lentz / Brookhaven National Laboratory.

“Until we did this work, no one had observed the internal entanglement of protons in experimental high-energy collision data,” said Brookhaven Laboratory physicist Zhoudunming (Kong) Tu. states.

“For decades, we have had the traditional view of the proton as a collection of quarks and gluons, and we have had many questions about how the quarks and gluons are distributed within the proton, so-called single particles. The focus has been on understanding the nature of

“Now that we have evidence that quarks and gluons are entangled, this situation has changed. We have a much more complex and dynamic system.”

“This latest paper further deepens our understanding of how entanglement affects the structure of protons.”

“Mapping the entanglement between quarks and gluons inside the proton provides insight into other complex questions in nuclear physics, such as how parts of the larger nucleus affect the proton’s properties. There is a possibility that

“This will be one of the focuses of future experiments at the Electron-Ion Collider (EIC), a nuclear physics research facility scheduled to open at Brookhaven Laboratory in the 2030s.”

In their study, Dr. Tu and his colleagues used the language and equations of quantum information science to predict how entanglement would affect particles flowing from collisions between electrons and protons.

Such collisions are a common approach to probing the structure of protons, most recently performed at the Hadron Electron Ring Accelerator (HERA) particle collider in Hamburg, Germany, from 1992 to 2007, and were used to investigate the future EIC. Experiments are also planned.

The equation predicts that if quarks and gluons are entangled, it can be revealed from the entropy of the collision, or disorder.

“Think of a child’s cluttered bedroom with laundry and other things strewn about. Entropy is very high in that cluttered room,” Dr. Tu said.

Calculations show that protons with maximally entangled quarks and gluons (high “entanglement entropy”) should produce a large number of particles with a “random” distribution (high entropy).

“For maximally entangled quarks and gluons, a simple relationship exists that predicts the entropy of particles produced in high-energy collisions,” says the theory, which is affiliated with both Brookhaven Institute and Stony Brook University. said Dr. Dmitri Kharziyev of the house. .

“In our paper, we used experimental data to test this relationship.”

The scientists started by analyzing data from proton-proton collisions at CERN’s Large Hadron Collider, but they also wanted to look at “cleaner” data produced by electron-proton collisions. .

Physicists have cataloged detailed information from data recorded from 2006 to 2007, including how particle production and distributions change, as well as a wide range of other information about the collisions that produced these distributions. It became.

When we compared the HERA data with the entropy calculations, the results were in perfect agreement with our predictions.

These analyzes, including the latest results on how the particle distribution changes at different angles from the point of collision, provide strong evidence that quarks and gluons inside the proton are maximally entangled .

“Unraveling the entanglement between quarks and gluons reveals the nature of their strong force interactions,” Dr. Kharziyev said.

“It could provide further insight into what confines quarks and gluons inside protons, one of the central questions in nuclear physics investigated at the EIC.”

“Maximum entanglement inside the proton appears as a result of strong interactions that produce large numbers of quark-antiquark pairs and gluons.”

of the team work appear in the diary Report on advances in physics.

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Martin Henczynski others. 2024. QCD evolution of entanglement entropy. Progressive member. physics 87, 120501; doi: 10.1088/1361-6633/ad910b

This article is based on a press release provided by Brookhaven National Laboratory.

Source: www.sci.news