Person: Mathieu, Vincent
Universidad Complutense de Madrid
Faculty / Institute
Now showing 1 - 6 of 6
- Publicationπ− p → η() π− p in the double-Regge region(Springer, 2021-07-23) Bibrzycki, Ł.; Fernández Ramírez, C.; Mathieu, Vincent; Mikhasenko, M.; Albaladejo, M.; Hiller Blin, A. N.; Pilloni, A.; Szczepaniak, A. P.The production of η(′)π pairs constitutes one of the golden channels to search for hybrid exotics, with explicit gluonic degrees of freedom. Understanding the dynamics and backgrounds associated to η(′)π production above the resonance region is required to impose additional constraints to the resonance extraction. We consider the reaction π−p→η(′)π−p measured by COMPASS. We show that the data in 2.4
- PublicationInterpretation of the LHCb P-c (4312)(+) Signal(American Physical Society, 2019-08-29) Fernández Ramírez, C.; Pilloni, A.; Albaladejo, M.; Jackura, A.; Mathieu, Vincent; Mikhasenko, M.; Silva Castro, J. A.; Szczepaniak, A. P.We study the nature of the new signal reported by LHCb in the J/psi p spectrum. Based on the S-matrix principles, we perform a minimum-bias analysis of the underlying reaction amplitude, focusing on the analytic properties that can be related to the microscopic origin of the P-c(4312)(+) peak. By exploring several amplitude parametrizations, we find evidence for the attractive effect of the Sigma(+)(c)(D) over bar (0) channel, which is not strong enough, however, to form a bound state.
- PublicationPole position of the a_1 (1260) from tau-decay(American Physical Society, 2018-11-28) Mikhasenko, M.; Pilloni, A.; Jackura, A.; Albadalejo, M.; Fernández Ramírez, César; Mathieu, Vincent; Nys, J.; Rodas Bilbao, Arkaitz; Ketzer, B.; Szczepaniak, Adam P.We perform an analysis of the three-pion system with quantum numbers J(PC) = 1(++) thornthorn produced in the weak decay of tau leptons. The interaction is known to be dominated by the axial meson alpha(1) (1260). We build a model based on approximate three-body unitary and fix the free parameters by fitting it to the ALEPH data on tau- -> pi(-)pi(+)pi(-)nu(tau) decay. We then perform the analytic continuation of the amplitude to the complex energy plane. The singularity structures related to the pi pi subchannel resonances are carefully addressed. Finally, we extract the alpha(1) (1260) pole position m(p)((a1(1260)) - i Gamma((a1(1260))(p) /2 with m(p)((a1(1260)) = (1209 +/- 4(-9)(+12)) MeV, Gamma((a1(1260))(p) = (576 +/- 11(-20)(+89)) MeV.
- PublicationThree-body scattering: ladders and resonances(Springer, 2019-08-14) Mikhasenko, M.; Wunderlich, Y.; Jackura, A.; Mathieu, Vincent; Pilloni, A.; Ketzer, B.; Szczepaniak, A.P.We discuss unitarity constraints on the dynamics of a system of three interacting particles. We show how the short-range interaction that describes three-body resonances can be separated from the long-range exchange processes, in particular the one-pion-exchange process. It is demonstrated that unitarity demands a specific functional form of the amplitude with a clear interpretation: the bare three-particle resonances are dressed by the initial- and final-state interaction, in a way that is consistent with the considered long-range forces. We postulate that the resonance kernel admits a factorization in the energy variables of the initial- and the final-state particles. The factorization assumption leads to an algebraic form for the unitarity equations, which is reminiscent of the well-known two-body-unitarity condition and approaches it in the limit of the narrow-resonance approximation.
- PublicationMoments of angular distribution and beam asymmetries in ηπ0 photoproduction at GlueX(APS Physics, 2019-08-17) Mathieu, Vincent; Albaladejo, M.; Fernández Ramírez, C.; Jackura, A.; Mikhasenko, M.; Pilloni, A.; Szczepaniak, A. P.In the search for exotic mesons, the GlueX Collaboration will soon extract moments of the ηπ0 angular distribution. In the perspective of these results, we generalize the formalism of moment extraction to the case in which the two mesons are produced with a linearly polarized beam and build a model for the reaction γ⃗p → ηπ0p. The model includes resonant S, P, and D waves in ηπ0, produced by natural exchanges. Moments of the ηπ0 angular distribution are computed with and without the P wave, to illustrate the sensitivity to exotic resonances. Although little sensitivity to the P wave is found in moments of even angular momentum, moments of odd angular momentum are proportional to the interference between the P wave and the dominant S and D waves. We also generalize the definition of the beam asymmetry for two mesons photoproduction and show that, when the meson momenta are perpendicular to the reaction plane, the beam asymmetry enhances the sensitivity to the exotic P wave.
- PublicationEquivalence of three-particle scattering formalisms(Springer, 2019-08-13) Jackura, A.; Dawid, S. M.; Fernández Ramírez, C.; Mathieu, Vincent; Mikhasenko, M.; Pilloni, A.; Sharpe, S. R.; Szczepaniak, A. P.In recent years, different on-shell 3 → 3 scattering formalisms have been proposed to be applied to both lattice QCD and infinite-volume scattering processes. We prove that the formulation in the infinite volume presented by Hansen and Sharpe in [M. T. Hansen and S. R. Sharpe, Phys. Rev. D 92, 114509 (2015).] and subsequently Briceño et al. in [R. A. Briceño, M. T. Hansen, and S. R. Sharpe, Phys. Rev. D 95, 074510 (2017).] can be recovered from the B -matrix representation, derived on the basis of S -matrix unitarity, presented by Mai et al. in [M. Mai, B. Hu, M. Döring, A. Pilloni, and A. Szczepaniak, Eur. Phys. J. A 53, 177 (2017).] and Jackura et al. in [A. Jackura, C. Fernández-Ramírez, V. Mathieu, M. Mikhasenko, J. Nys, A. Pilloni, K. Saldaña, N. Sherrill, and A. P. Szczepaniak (JPAC Collaboration), Eur. Phys. J. C 79, 56 (2019).] Therefore, both formalisms in the infinite volume are equivalent and the physical content is identical. Additionally, the Faddeev equations are recovered in the nonrelativistic limit of both representations.