2023/05/18 by А. Туміно, G. G. Rapisarda, M. La Cognata +13 · 1 voice
Physics and Astronomy · #Nuclear physics research studies #Quantum Chromodynamics and Particle Interactions #Atomic and Molecular Physics
paper · pdf · doi:10.1038/s42005-023-01221-0
openalex publication_date 2023/05/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/23
Abstract The Coulomb-free 1 S 0 proton-proton ( p - p ) scattering length relies heavily on numerous and distinct theoretical techniques to remove the Coulomb contribution. Here, it has been determined from the half-off-the-energy-shell p - p scattering cross section measured at center-of-mass energies below 1 MeV using the quasi-free p + d → p + p + n reaction. A Bayesian data-fitting approach using the expression of the s-wave nucleon-nucleon scattering cross section returned a p - p scattering length app=-18.17-0.58+0.52| stat± 0.01syst <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mrow> <mml:mi>a</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>p</mml:mi> <mml:mi>p</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:mo>−</mml:mo> <mml:mn>18.1</mml:mn> <mml:msubsup> <mml:mrow> <mml:mn>7</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.58</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.52</mml:mn> </mml:mrow> </mml:msubsup> <mml:msub> <mml:mrow> <mml:mo>∣</mml:mo> </mml:mrow> <mml:mrow> <mml:mi>s</mml:mi> <mml:mi>t</mml:mi> <mml:mi>a</mml:mi> <mml:mi>t</mml:mi> </mml:mrow> </mml:msub> <mml:mo>±</mml:mo> <mml:mn>0.0</mml:mn> <mml:msub> <mml:mrow> <mml:mn>1</mml:mn> </mml:mrow> <mml:mrow> <mml:mi>s</mml:mi> <mml:mi>y</mml:mi> <mml:mi>s</mml:mi> <mml:mi>t</mml:mi> </mml:mrow> </mml:msub> </mml:math> fm and effective range r 0 = 2.80 ± 0.05 s t a t ± 0.001 s y s t fm. A model based on universality concepts has been developed to interpret this result. It accounts for the short-range interaction as a whole, nuclear and residual electromagnetic, according to what the s-wave phase-shift δ does in the description of low-energy nucleon-nucleon scattering data. We conclude that our parameters are representative of the short-range physics and propose to assess the charge symmetry breaking of the short-range interaction instead of just the nuclear interaction. This is consistent with the current understanding that the charge dependence of nuclear forces is due to different masses of up-down quarks and their electromagnetic interactions. This achievement suggests that these properties have a lesser than expected impact in the context of the charge symmetry breaking.