Person: Mathieu, Vincent
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First Name
Vincent
Last Name
Mathieu
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Físicas
Department
Física Teórica
Area
Física Teórica
Identifiers
8 results
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Item Three-body scattering: ladders and resonances(Journal of High Energy Physics, 2019) 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.Item Moments of angular distribution and beam asymmetries in ηπ0 photoproduction at GlueX(Physical Review D, 2019) 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.Item Dynamics in near-threshold J / ψ photoproduction(Physical Review D, 2023) Winney, D.; Fernández-Ramírez, C.; Pilloni, A.; Hiller Blin, A.N.; Albaladejo, M.; Bibrzycki, L.; Hammoud, N.; Liao, J.; Mathieu, Vincent; Montaña, G.; Perry, R.J.; Shastry, V.; Smith, W.A.; Szczepaniak, A.P.The study of J/ψ photoproduction at low energies has consequences for the understanding of multiple aspects of nonperturbative QCD, ranging from mechanical properties of the proton to the binding inside nuclei and the existence of hidden-charm pentaquarks. Factorization of the photon-cc¯ and nucleon dynamics or vector meson dominance are often invoked to justify these studies. Alternatively, open-charm intermediate states have been proposed as the dominant mechanism underlying J/ψ photoproduction. As the latter violates this factorization, it is important to estimate the relevance of such contributions. We analyze the latest differential and integrated photoproduction cross sections from the GlueX and J/ψ-007 experiments. We show that the data can be adequately described by a small number of partial waves, which we parametrize with generic models enforcing low-energy unitarity. The results suggest a non-negligible contribution from open-charm intermediate states. Furthermore, most of the models present an elastic scattering length incompatible with previous extractions based on vector meson dominance and thus call into question its applicability to heavy mesons. Our results indicate a wide array of physics possibilities that are compatible with present data and need to be disentangled.Item Interpretation of the LHCb P-c (4312)(+) Signal(Physical review letters, 2019) 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.Item π− p → η() π− p in the double-Regge region(The European Physical Journal C, 2021) 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 2.4Item Pole position of the a_1 (1260) from tau-decay(Physical review D, 2018) 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.Item Ambiguities in partial wave analysis of two spinless meson photoproduction(Physical Review D, 2023) Smith, W. A.; Glazier, D. I.; Mathieu, Vincent; Albaladejo, M.; Albrecht, M.; Baldwin, Z.; Fernandez-Ramirez, C.; Hammoud, N.; Mikhasenko, M.; Montaña, G.; Perry, R. J.; Pilloni, A.; Shastry, V.; Szczepaniak, A. P.; Winney, D.We describe the formalism to analyze the mathematical ambiguities arising in partial-wave analysis of two spinless mesons produced with a linearly polarized photon beam. We show that partial waves are uniquely defined when all accessible observables are considered, for a wave set which includes S and D waves. The inclusion of higher partial waves does not affect our results, and we conclude that there are no mathematical ambiguities in partial-wave analysis of two mesons produced with a linearly polarized photon beam. We present Monte Carlo simulations to illustrate our results.Item Equivalence of three-particle scattering formalisms(Physical Review D, 2019) 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.