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1. Towards the understanding of the genuine three-body interaction for p–p–p and p–p–$$\Lambda $$

   https://doi.org/10.1140/epja/s10050-023-00998-6  

   Acharya, S.; Adamová, D.; Adler, A.; Aglieri Rinella, G.; Agnello, M.; Agrawal, N.; Ahammed, Z.; Ahmad, S.; Ahn, S. U.; Ahuja, I.; et al (July 2023, The European Physical Journal A)

   Abstract Three-body nuclear forces play an important role in the structure of nuclei and hypernuclei and are also incorporated in models to describe the dynamics of dense baryonic matter, such as in neutron stars. So far, only indirect measurements anchored to the binding energies of nuclei can be used to constrain the three-nucleon force, and if hyperons are considered, the scarce data on hypernuclei impose only weak constraints on the three-body forces. In this work, we present the first direct measurement of the p–p–p and p–p– $$\Lambda $$ Λ systems in terms of three-particle correlation functions carried out for pp collisions at $$\sqrt{s} = 13$$ s = 13 TeV. Three-particle cumulants are extracted from the correlation functions by applying the Kubo formalism, where the three-particle interaction contribution to these correlations can be isolated after subtracting the known two-body interaction terms. A negative cumulant is found for the p–p–p system, hinting to the presence of a residual three-body effect while for p–p– $$\Lambda $$ Λ the cumulant is consistent with zero. This measurement demonstrates the accessibility of three-baryon correlations at the LHC. 

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2. Study of the p–p–K$$^{+}$$ and p–p–K$$^{-}$$ dynamics using the femtoscopy technique

   https://doi.org/10.1140/epja/s10050-023-01139-9  

   Acharya, S; Adamová, D; Adler, A; Aglieri_Rinella, G; Agnello, M; Agrawal, N; Ahammed, Z; Ahmad, S; Ahn, S U; Ahuja, I; et al (December 2023, The European Physical Journal A)

   Abstract The interactions of kaons (K) and antikaons ($$\mathrm {\overline{K}}$$ $\overline{K}$) with few nucleons (N) were studied so far using kaonic atom data and measurements of kaon production and interaction yields in nuclei. Some details of the three-body KNN and$$\mathrm {\overline{K}}$$ $\overline{K}$NN dynamics are still not well understood, mainly due to the overlap with multi-nucleon interactions in nuclei. An alternative method to probe the dynamics of three-body systems with kaons is to study the final state interaction within triplet of particles emitted in pp collisions at the Large Hadron Collider, which are free from effects due to the presence of bound nucleons. This Letter reports the first femtoscopic study of p–p–K$$^+$$ ${}^{+}$and p–p–K$$^-$$ ${}^{-}$correlations measured in high-multiplicity pp collisions at$$\sqrt{s}$$ $\sqrt{s}$= 13 TeV by the ALICE Collaboration. The analysis shows that the measured p–p–K$$^+$$ ${}^{+}$and p–p–K$$^-$$ ${}^{-}$correlation functions can be interpreted in terms of pairwise interactions in the triplets, indicating that the dynamics of such systems is dominated by the two-body interactions without significant contributions from three-body effects or bound states. 

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3. Coulomb-free 1S0 p − p scattering length from the quasi-free p + d → p + p + n reaction and its relation to universality

   https://doi.org/10.1038/s42005-023-01221-0  

   Tumino, Aurora; Rapisarda, Giuseppe G.; La Cognata, Marco; Oliva, Alessandro; Kievsky, Alejandro; Bertulani, Carlos A.; D’Agata, Giuseppe; Gattobigio, Mario; Guardo, Giovanni L.; Lamia, Livio; et al (May 2023, Communications Physics)

   Abstract The Coulomb-free¹S₀proton-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-shellp-pscattering cross section measured at center-of-mass energies below 1 MeV using the quasi-freep + d → p + p + nreaction. A Bayesian data-fitting approach using the expression of the s-wave nucleon-nucleon scattering cross section returned ap-pscattering length$${a}_{pp}=-18.1{7}_{-0.58}^{+0.52}{| }_{stat}\pm 0.0{1}_{syst}$$ $a_{pp}=-18.17_{-0.58}^{+0.52}{\mid }_{stat}\pm 0.01_{syst}$fm and effective ranger₀ = 2.80 ± 0.05_stat ± 0.001_systfm. 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-shiftδdoes 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. 

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4. A carbene-stabilized diphosphorus: a triple-bonded diphosphorus (PP) and a bis(phosphinidene) (P–P) transfer agent

   https://doi.org/10.1039/D4SC05091F  

   Yoon, Joseph S; Abdellaoui, Mehdi; Gembicky, Milan; Bertrand, Guy (October 2024, Chemical Science)

   The bis-monosubstituted aminocarbene-P₂adduct is a generator of P₂, under the classical triple-bonded form (PP), but it also acts as a bis(phosphinidene) (P–P) synthetic equivalent. 

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5. p -Euler equations and p -Navier–Stokes equations

   https://doi.org/10.1016/j.jde.2017.12.023  

   Li, Lei; Liu, Jian-Guo (April 2018, Journal of Differential Equations)