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1. $$\omega \rightarrow 3\pi $$ and $$\omega \pi ^{0}$$ transition form factor revisited

   https://doi.org/10.1140/epjc/s10052-020-08576-6  

   Albaladejo, M.; Danilkin, I.; Gonzàlez-Solís, S.; Winney, D.; Fernández-Ramírez, C.; Blin, A. N.; Mathieu, V.; Mikhasenko, M.; Pilloni, A.; Szczepaniak, A. (December 2020, The European Physical Journal C)

   null (Ed.)

   Abstract In light of recent experimental results, we revisit the dispersive analysis of the $$\omega \rightarrow 3\pi $$ ω → 3 π decay amplitude and of the $$\omega \pi ^0$$ ω π 0 transition form factor. Within the framework of the Khuri–Treiman equations, we show that the $$\omega \rightarrow 3\pi $$ ω → 3 π Dalitz-plot parameters obtained with a once-subtracted amplitude are in agreement with the latest experimental determination by BESIII. Furthermore, we show that at low energies the $$\omega \pi ^0$$ ω π 0 transition form factor obtained from our determination of the $$\omega \rightarrow 3\pi $$ ω → 3 π amplitude is consistent with the data from MAMI and NA60 experiments. 

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2. Measurement of νˉμ\bar{\nu}_{\mu}νˉμ​ Charged-Current Single π−\pi^{-}π− Production on Hydrocarbon in the Few-GeV Region using MINERvA

   T. Le (September 2019, Physical review)

   The antineutrino scattering channel ¯νμCH→μ+π−X (nucleon(s)) is analyzed in the incident energy range 1.5 to 10 GeV using the MINERvA detector at Fermilab. Differential cross sections are reported as functions of μ+ momentum and production angle, π− kinetic energy and production angle, and antineutrino energy and squared four-momentum transfer. Distribution shapes are generally reproduced by simulations based on the GENIE, NuWro, and GiBUU event generators, however GENIE (GiBUU) overestimates (underestimates) the cross section normalizations by 8% (10%). Comparisons of data with the GENIE-based reference simulation probe conventional treatments of cross sections and pion intranuclear rescattering. The distribution of nontrack vertex energy is used to decompose the signal sample into reaction categories, and cross sections are determined for the exclusive reactions μ+π−n and μ+π−p. A similar treatment applied to the published MINERvA sample ¯νμCH→μ+π0X[nucleon(s)] has determined the μ+π0n cross section, and the latter is used with σ(π−n) and σ(π−p) to carry out an isospin decomposition of ¯νμ-induced CC(π). The ratio of magnitudes and relative phase for isospin amplitudes A3 and A1 thereby obtained are: R¯ν=0.99±0.19 and ϕ¯ν=93°±7°. Our results are in agreement with bubble chamber measurements made four decades ago. 

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3. Search for the doubly charmed baryon $$ {\varXi}_{cc}^{+} $$ in the $$ {\varXi}_c^{+}{\pi}^{-}{\pi}^{+} $$ final state

   https://doi.org/10.1007/JHEP12(2021)107  

   Aaij, R.; Abdelmotteleb, A. S.; Abellán Beteta, C.; Ackernley, T.; Adeva, B.; Adinolfi, M.; Afsharnia, H.; Agapopoulou, C.; Aidala, C. A.; Aiola, S.; et al (December 2021, Journal of High Energy Physics)

   A bstract A search for the doubly charmed baryon $$ {\varXi}_{cc}^{+} $$ Ξ cc + is performed in the $$ {\varXi}_c^{+}{\pi}^{-}{\pi}^{+} $$ Ξ c + π − π + invariant-mass spectrum, where the $$ {\varXi}_c^{+} $$ Ξ c + baryon is reconstructed in the pK − π + final state. The study uses proton-proton collision data collected with the LHCb detector at a centre- of-mass energy of 13 TeV, corresponding to a total integrated luminosity of 5.4 fb − 1 . No significant signal is observed in the invariant-mass range of 3.4–3.8 GeV/ c 2 . Upper limits are set on the ratio of branching fractions multiplied by the production cross-section with respect to the $$ {\varXi}_{cc}^{++} $$ Ξ cc + + → ( $$ {\varXi}_c^{+} $$ Ξ c + → pK − π + ) π + decay for different $$ {\varXi}_{cc}^{+} $$ Ξ cc + mass and lifetime hypotheses in the rapidity range from 2.0 to 4.5 and the transverse momentum range from 2.5 to 25 GeV/ c . The results from this search are combined with a previously published search for the $$ {\varXi}_{cc}^{+} $$ Ξ cc + → $$ {\varLambda}_c^{+} $$ Λ c + K − π + decay mode, yielding a maximum local significance of 4.0 standard deviations around the mass of 3620 MeV/ c 2 , including systematic uncertainties. Taking into account the look-elsewhere effect in the 3.5–3.7 GeV/ c 2 mass window, the combined global significance is 2.9 standard deviations including systematic uncertainties. 

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4. Interplay of hidden orbital order and superconductivity in CeCoIn5

   https://doi.org/10.1038/s41467-023-38760-7  

   Chen, Weijiong; Neerup Breiø, Clara; Massee, Freek; Allan, Milan P.; Petrovic, ‪Cedomir; Davis, J. C.; Hirschfeld, Peter J.; Andersen, Brian M.; Kreisel, Andreas (December 2023, Nature Communications)

   Abstract Visualizing atomic-orbital degrees of freedom is a frontier challenge in scanned microscopy. Some types of orbital order are virtually imperceptible to normal scattering techniques because they do not reduce the overall crystal lattice symmetry. A good example is d xz / d yz (π,π) orbital order in tetragonal lattices. For enhanced detectability, here we consider the quasiparticle scattering interference (QPI) signature of such (π,π) orbital order in both normal and superconducting phases. The theory reveals that sublattice-specific QPI signatures generated by the orbital order should emerge strongly in the superconducting phase. Sublattice-resolved QPI visualization in superconducting CeCoIn 5 then reveals two orthogonal QPI patterns at lattice-substitutional impurity atoms. We analyze the energy dependence of these two orthogonal QPI patterns and find the intensity peaked near E  = 0, as predicted when such (π,π) orbital order is intertwined with d -wave superconductivity. Sublattice-resolved superconductive QPI techniques thus represent a new approach for study of hidden orbital order. 

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5. QCD Predictions for Physical Multimeson Scattering Amplitudes

   https://doi.org/10.1103/6nql-yrhw  

   Dawid, Sebastian M; Draper, Zachary T; Hanlon, Andrew D; Hörz, Ben; Morningstar, Colin; Romero-López, Fernando; Sharpe, Stephen R; Skinner, Sarah (July 2025, Physical Review Letters)

   We use lattice QCD calculations of the finite-volume spectra of systems of two and three mesons to determine, for the first time, three-particle scattering amplitudes with physical quark masses. Our results are for combinations of π+ and K+, at a lattice spacing a=0.063 fm, and in the isospin-symmetric limit. We also obtain accurate results for maximal-isospin two-meson amplitudes, with those for ${\pi }^{+}{K}^{+}$and $2K^{+}$being the first determinations at the physical point. Dense lattice spectra are obtained using the stochastic Laplacian-Heaviside method, and the analysis leading to scattering amplitudes is done using the relativistic finite-volume formalism. Results are compared to chiral perturbation theory and to phenomenological fits to experimental data, finding good agreement. 

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