A High-Resolution Imaging of the Collinear Substructure of the Proton
Physicist Giacomo Magni investigated several fundamental questions about the proton, the most common object we experience in our world. Protons are, in fact, complex systems composed of tightly bound elementary particles: quarks and gluons. Their interaction belongs to the strongest forces in nature, making the proton a stable object from which we all exist. Understanding how these smaller components interact and distribute their energy within the proton is crucial for advancing our knowledge of particle physics.
In particular, the substructure of the proton becomes relevant during high-energy collisions, such as those at the Large Hadron Collider (LHC). This internal structure is described by Parton Distribution Functions (PDFs), which serve as the primary tool used in our research. PDFs describe how the energy of the proton is likely distributed among quarks and gluons. As such, PDFs are essential for interpreting data from LHC experiments and making predictions about particle behavior under extreme conditions. Like any physical quantity, PDFs are subject to uncertainties. These can impact our ability to identify new particles or verify existing theories, such as the Standard Model of particle physics.
Key Findings
- Approximate N3LO QCD PDFs: The researchers refine our knowledge of PDFs by accounting for suppressed effects and theoretical errors, which are often neglected but may be relevant in current and future LHC analyses.
- Intrinsic Charm: The researchers provide initial evidence of a non-vanishing intrinsic charm contribution to the proton structure. This phenomenon suggests that virtual charm quarks are present in low-energy protons and are not only generated at high energy.
- Polarized PDFs and Proton Spin: The researchers revisit the determination of spin-dependent PDFs. The study further suggests that quarks contribute only a fraction of the total proton spin, while the gluon contribution remains uncertain.
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