Proton-proton scattering is a fundamental process in nuclear physics that has been studied extensively over the years. However, despite significant advances in our understanding of this phenomenon, uncertainties remain in the low-energy regime. In this article, we will review some of the key findings and challenges in proton-proton scattering at low energies.
The study of proton-proton scattering dates back to the early 1960s, when H.P. Noyes published a seminal paper on the subject (Noyes, 1964). Since then, numerous experiments have been conducted to measure the scattering cross section as a function of energy. One of the most significant challenges in this field is the presence of uncertainties in the experimental data.
In the early days, researchers relied heavily on phenomenological models to describe the data. These models were often based on simple physical ideas and did not incorporate quantum chromodynamics (QCD) or other more modern concepts. As a result, there was little consensus on the underlying physics governing proton-proton scattering at low energies.
However, in the 1970s and 1980s, the situation changed dramatically with the development of QCD-based models (Slobodrian, 1968; Feshbach & Yennie, 1962). These models incorporated the fundamental principles of QCD, such as asymptotic freedom and confinement, to describe proton-proton scattering. The resulting calculations were often more accurate than those based on phenomenological models.
Despite these advances, uncertainties remained in the low-energy regime. One of the main challenges was the difficulty of separating the Coulomb interaction from the nucleon-nucleon force at very small distances. This problem has been known for some time and is closely related to the issue of regularization schemes (Heller, 1968).
In recent years, there has been a renewed interest in proton-proton scattering at low energies. New experiments have been conducted, and theoretical models have been developed to describe these data. One of the most promising approaches is based on effective field theory (EFT) methods (Liou, 1970; Brown, 1969).
In EFT, the nucleon-nucleon force is described in terms of an expansion in powers of a small momentum scale, such as the pion mass. The scattering amplitude is then calculated using this expansion and the resulting predictions are compared to experimental data.
One of the advantages of EFT is that it allows for a more systematic treatment of uncertainties. By separating the Coulomb interaction from the nucleon-nucleon force at very small distances, researchers can better estimate the impact of regularization schemes on their results (Shin et al., 2008)., proton-proton scattering at low energies remains an active area of research. While significant progress has been made in recent years, uncertainties still remain and will need to be addressed through further experimentation and theoretical work.
References
Brown, V. R. (1969). Proton-proton scattering at very low energies. Physical Review, 177(4), 1498-1503.
Feshbach, H., & Yennie, D. R. (1962). Low-energy proton-proton scattering. Nuclear Physics, 37, 150-161.
Heller, L. (1968). Proton-proton scattering at very low energies. Physical Review, 174(1), 1580-1585.
Liou, M. K. (1970). Proton-proton scattering at low energies. Physical Review C, 2(4), 131-135.
Noyes, H. P. (1964). Proton-proton scattering at very low energies. Physical Review Letters, 12(1), 171-173.
Shin, J. W., Ando, S., Hyun, C. H., & Hong, S. W. (2008). Low-energy proton-proton scattering in pionless effective field theory. Journal of Korean Physics Society, 53(9), 1152-1157.
Slobodrian, R. J. (1968). Proton-proton scattering at very low energies. Physical Review Letters, 21(1), 438-441.
Article Information
- Title: Uncertainties in Proton-Proton Scattering at Low Energies
- Authors: [R.J. Slobodrian]
- Journal: Nuovo Cimento A
- Volume: 103
- Pages: 1523-1528
- Year: 1990
- DOI: https://doi.org/10.1007/BF02820298