The study is an important step forward in our understanding of the fundamental laws of nature.
A new study conducted by Professor Chen Xurong of the Institute of Modern Physics of the Chinese Academy of Sciences reveals the secrets of the origin of the proton mass. The results, published in the journal Physical Review D on February 27, indicate that the effect of heavy quarks on the proton mass may be significantly larger than previously thought.
Nucleons made up of protons and neutrons form more than 99% of the observed mass of the universe. The mechanisms responsible for the mass of nucleons are closely related to such fundamental phenomena as the conformal anomaly, color charge restriction, and spontaneous symmetry breaking .
Therefore, the study of the nature of the mass of nucleons is of fundamental importance for understanding the structure of nucleons and the development of quantum chromodynamics. This area of research helps to shed light on some of the deeper questions of particle physics and the structure of matter. Understanding the fundamental mechanisms that shape the mass of protons and neutrons may open the door to new physics beyond the Standard Model.
Previously, it was assumed that the mass of quarks inside protons mainly comes from their constituent quarks: two upper quarks and one lower quark, while the contribution of other types of quarks was considered insignificant. However, recent studies suggest the possible presence of heavier types of quarks in protons, despite the lack of direct experimental evidence of their significant effect on the proton mass.
In the new study, having established a connection between the energy of the proton quantum anomaly and the total sigma term (including the contributions of light and heavy quarks to the proton mass), the scientists extracted the sigma term from experimental data using photoproduction of vector mesons at the threshold.
The results showed a significantly larger sigma-term of heavy quarks, approximately 337 MeV (dipole fit approach) and 455 MeV (exponential fit), which is 36-48% of the total proton mass (938 MeV). The statistical significance of the non-zero value (exponential fit) reached about seven standard deviations, which corresponds to a probability of 99.999999999744%.
In addition, the use of data from the two experimental groups and the Kolmogorov-Smirnov consensus testing method confirmed the compatibility of the sigma term extracted from both data sets.
This study opens up new perspectives for future studies of the origin of the proton mass. It provides new experimental data that can be used in future experiments at electron-ion colliders (EIC). The results show the importance of measuring the proton's structural functions for understanding the mechanisms of mass generation. The data also indicate that experiments at the EIC will be able to shed light on the role of gluons and quarks in proton mass formation. Overall, this is an important step forward in fundamental research of the proton structure and the origin of mass.
A new study conducted by Professor Chen Xurong of the Institute of Modern Physics of the Chinese Academy of Sciences reveals the secrets of the origin of the proton mass. The results, published in the journal Physical Review D on February 27, indicate that the effect of heavy quarks on the proton mass may be significantly larger than previously thought.
Nucleons made up of protons and neutrons form more than 99% of the observed mass of the universe. The mechanisms responsible for the mass of nucleons are closely related to such fundamental phenomena as the conformal anomaly, color charge restriction, and spontaneous symmetry breaking .
Therefore, the study of the nature of the mass of nucleons is of fundamental importance for understanding the structure of nucleons and the development of quantum chromodynamics. This area of research helps to shed light on some of the deeper questions of particle physics and the structure of matter. Understanding the fundamental mechanisms that shape the mass of protons and neutrons may open the door to new physics beyond the Standard Model.
Previously, it was assumed that the mass of quarks inside protons mainly comes from their constituent quarks: two upper quarks and one lower quark, while the contribution of other types of quarks was considered insignificant. However, recent studies suggest the possible presence of heavier types of quarks in protons, despite the lack of direct experimental evidence of their significant effect on the proton mass.
In the new study, having established a connection between the energy of the proton quantum anomaly and the total sigma term (including the contributions of light and heavy quarks to the proton mass), the scientists extracted the sigma term from experimental data using photoproduction of vector mesons at the threshold.
The results showed a significantly larger sigma-term of heavy quarks, approximately 337 MeV (dipole fit approach) and 455 MeV (exponential fit), which is 36-48% of the total proton mass (938 MeV). The statistical significance of the non-zero value (exponential fit) reached about seven standard deviations, which corresponds to a probability of 99.999999999744%.
In addition, the use of data from the two experimental groups and the Kolmogorov-Smirnov consensus testing method confirmed the compatibility of the sigma term extracted from both data sets.
This study opens up new perspectives for future studies of the origin of the proton mass. It provides new experimental data that can be used in future experiments at electron-ion colliders (EIC). The results show the importance of measuring the proton's structural functions for understanding the mechanisms of mass generation. The data also indicate that experiments at the EIC will be able to shed light on the role of gluons and quarks in proton mass formation. Overall, this is an important step forward in fundamental research of the proton structure and the origin of mass.
