Search arXiv⌕ Search

arXiv subjects

Vincent Mathieu

Publications and source records attributed to Vincent Mathieu.

At least 19 recordsLinked to original sources
arXiv2026

First determination of vector and tensor couplings from polarized $\pi\Delta$ photoproduction

The couplings between hadrons encode the dynamics of quantum chromodynamics. While many couplings can be calculated from decay widths, in some cases the decays are kinematically forbidden and hence are not directly accessible. We use a Regge framework to determine these couplings from high-energy polarized scattering processes. We apply this to the $\pi\Delta$ photoproduction that was recently studied at GlueX and provide the first determination of the complete set of $N\Delta$ couplings to $\rho$, $b_1$, and $a_2$.

hep-ph↗
arXiv2026

Finite-volume analysis of the $H$-dibaryon including left-hand-cut effects

We implement the finite-volume $N/D$ representation to study two-baryon interactions from lattice QCD data. We include the left-hand cut induced by one-pion exchange in this formalism, and study the $H$-dibaryon at the SU(3)$_\text{F}$-symmetric point, with a pion mass around $417$ MeV. The $N/D$ formalism is then compared to the L\"uscher quantization condition, used to describe the same system via effective-range expansions. The results show a mild but statistically significant effect produced by the inclusion of the left-hand cut, especially on the binding energy of the $H$-dibaryon.

hep-lat↗
arXiv2026

Mechanisms of high energy polarized photoproduction of $\pi^{-}\Delta^{++}$

We present an amplitude analysis of high-energy polarized photoproduction of $\pi^-\Delta^{++}$ within a Regge exchange framework. A Regge amplitude model incorporating $\pi$, $\rho$, $b_1$, and $a_2$ trajectory exchanges is fit simultaneously to spin density matrix elements measured by the GlueX experiment at photon energies of $E_\gamma = 8.2$--$8.8$ GeV and differential cross section data from SLAC. By including SDME data, the fit constrains not only the magnitudes but also the relative phases of the helicity amplitudes. The results confirm the dominance of pion exchange at small momentum transfer, while natural parity exchanges become significant at larger $t$. We analytically continue the $s$-channel amplitude to the $t$-channel, taking care of the kinematical singularities, and isolate the dynamical residues at the meson poles. The extracted $\pi N\Delta$ coupling constant is found to be consistent with the value obtained from the decay width of the $\Delta(1232)$. For the $\rho N\Delta$, $b_1 N\Delta$, and $a_2 N\Delta$ vertices, first extractions of the relevant coupling constants are provided.

hep-ph↗
arXiv2025

High-energy $\eta^{(\prime)}\pi$ photoproduction and the nature of exotic waves

The observation of hybrid mesons in photoproduction experiments can provide essential insight into the inner workings of quantum chromodynamics in the strong coupling regime. In particular, the study of final $\eta^{(\prime)}\pi$ states is of great interest due to the presence of the lowest lying hybrid candidate with manifestly exotic quantum numbers, the $\pi_1(1600)$. In this work, a double-vector exchange model with Reggeized $\rho$ and $\omega$ trajectories is developed to describe the photoproduction of $\eta^{(\prime)}\pi$ in the high-mass region. Results are presented for the differential cross sections and forward-backward asymmetries in the energy region of interest to the GlueX experiment. The model contains no free parameters, and reproduces the magnitude and $t$-dependence of existing CLAS data at $E_\gamma=5$\gev. The model predicts a stronger asymmetry in the $\eta^\prime \pi$ channel than in the $\eta \pi$ channel, consistent with what has previously been observed in pion beam experiments. This suggests that the sizeable production of exotic odd waves in $\eta'\pi$ is not necessarily related to the presence of gluon-rich environments. Confirmation of these predicted asymmetries from forthcoming GlueX data would enable further predictions of the low-energy spectrum.

hep-ph↗
arXiv2025

Elliptical Polarization in Partial Wave Analysis of Two Spinless Meson Photoproduction

Mathematical ambiguities in partial-wave analysis present a significant challenge to the extraction of resonance properties in hadronic reactions. Recent work has shown that while linear photon polarization can resolve continuous ambiguities in the photoproduction of two pseudoscalar mesons, a final complex conjugate ambiguity remains. In this work, we extend the partial-wave formalism to include circular and elliptical photon polarization. We demonstrate that the additional constraints provided by circularly polarized observables, which are sensitive to the imaginary parts of bilinear amplitude products, are sufficient to remove remaining mathematical ambiguities, yielding an improved partial-wave solution. Furthermore, we show that the resulting overconstrained system allows for a novel application: using the reaction dynamics themselves as a polarimeter. Using recent high-statistics data on rho(770) photoproduction from the GlueX experiment, we illustrate the viability of this technique in determining the degrees of beam polarization from the data. These results will benefit the next generation of photoproduction experiments at facilities such as Jefferson Lab and the future Electron-Ion Collider.

hep-ph↗
arXiv2025

Two- and Three-gluon Glueballs within the Helicity Formalism

Both positive and negative charge conjugation glueball spectra are computed with a constituent gluon approach. We first compute the spectrum of the Hamiltionian describing two-gluon bound states having $C=+$, before tackling the three-gluon bound states having $C=-$. We review the construction of two and three particle helicity states in order to build totally symmetric wave functions for our glueball states. In the literature, two different couplings schemes are used to build three particles states. We derive for the first time the relation between these two three-body state definitions. The glueball spectra are compared with those obtained from quantum chromodynamics simulations on a lattice. The two-gluon glueball spectra show a good agreement with the constituent approach and the numerical lattice simulations. The three-gluon spectrum is in overall agreement with the masses observed on the lattice but also predicts additional low-lying states.

hep-ph↗
arXiv2024

One Million Quality Factor Integrated Ring Resonators in the Mid-Infrared

We report ring resonators on a silicon germanium on silicon platform operating in the mid-infrared wavelength range around 3.5 - 4.6 {\mu}m with quality factors reaching up to one million. Advances in fabrication technology enable us to demonstrate such high Q-factors, which put silicon germanium at the forefront of mid-infrared integrated photonic platforms. The achievement of high Q is attested by the observation of degeneracy lifting between clockwise (CW) and counter-clockwise (CCW) resonances, as well as optical bistability due to an efficient power buildup in the rings.

physics.optics↗
arXiv2024

Towards a unified description of hadron scattering at all energies

The construction of general amplitudes satisfying symmetries and $S$-matrix constraints has been the primary tool in studying the spectrum of hadrons for over half a century. In this work, we present a new parameterization, which can fulfill many expectations of $S$-matrix and Regge theory and connects the essential physics of hadron scattering in the resonance region and in asymptotic limits. In this construction, dynamical information is entirely contained in Regge trajectories that generalize resonance poles in the complex energy plane to moving poles in the angular momentum plane. We highlight the salient features of the model, compare with existing literature on dispersive and dual amplitudes, and benchmark the formalism with an initial numerical application to the $\rho$ and $\sigma/f_0(500)$ mesons in $\pi\pi$ scattering.

hep-ph↗
arXiv2024

Revisiting gauge invariance and Reggeization of pion exchange

The Reggeized pion is expected to provide the main contribution to the forward cross section in light meson photoproduction reactions with charge exchange at high energies. We discuss the Reggeization of pion exchange in charged pion photoproduction with an emphasis on consistency with current conservation. We show that the gauge-invariant amplitude for the exchange of a particle with generic even spin $J\geq 2$ in the $t$-channel is analytic at $J=0$, and that it can be interpreted in terms of the nucleon electric current. This enables us to reconcile the dynamics in the $s$- and $u$-channel, which involves also nucleon exchanges, with the amplitude expressed in terms of $t$-channel partial waves, as required by Regge theory.

hep-ph↗
arXiv2024

Studying $\pi^+\pi^-$ photoproduction beyond Pomeron exchange

Forward photoproduction of $\pi^+\pi^-$ pairs with invariant mass of the order of $m_\rho\sim 770$ MeV is traditionally understood to be produced via Pomeron exchange. Based on a detailed analysis of the CLAS photoproduction data, it is shown that the dynamics of two-pion photoproduction for $|t|\gtrsim 0.5$ GeV$^2$ cannot be explained by Pomeron exchange alone. This motivates the development of a new theoretical model of two-pion photoproduction which incorporates both two-pion and pion-nucleon resonant contributions. After fitting free parameters, the model provides an excellent description of the low moments of the angular distribution measured at CLAS, and enables an assessment of the relative contributions of particular production mechanisms and an interpretation of the various features of the data in terms of these mechanisms.

hep-ph↗
arXiv2023

Studying the production mechanisms of light meson resonances in two-pion photoproduction

A theoretical model of two-pion photoproduction is presented. The model encodes the prominent $\rho(770)$ resonance and the expected leading background contribution coming from the Deck mechanism. To validate the model, angular moments are computed and compared with the CLAS dataset. After fitting a number of free parameters, the model provides a good description of the data.

hep-ph↗
arXiv2023

The case for an EIC Theory Alliance: Theoretical Challenges of the EIC

We outline the physics opportunities provided by the Electron Ion Collider (EIC). These include the study of the parton structure of the nucleon and nuclei, the onset of gluon saturation, the production of jets and heavy flavor, hadron spectroscopy and tests of fundamental symmetries. We review the present status and future challenges in EIC theory that have to be addressed in order to realize this ambitious and impactful physics program, including how to engage a diverse and inclusive workforce. In order to address these many-fold challenges, we propose a coordinated effort involving theory groups with differing expertise is needed. We discuss the scientific goals and scope of such an EIC Theory Alliance.

hep-ph↗
arXiv2022

Snowmass white paper: Need for amplitude analysis in the discovery of new hadrons

We highlight the need for the development of comprehensive amplitude analysis methods to further our understanding of hadron spectroscopy. Reaction amplitudes constrained by first principles of $S$-matrix theory and by QCD phenomenology are needed to extract robust interpretations of the data from experiments and from lattice calculations.

hep-ph↗
arXiv2022

Hadron Spectroscopy in Photoproduction

Recent decades have seen a resurge of interest in hadron spectroscopy, driven by new, high-luminosity experiments which have identified many new hadrons, both expected and unexpected. The large number of unexpected hadrons suggest contributions from additional quark and gluonic degrees of freedom to the hadronic spectrum beyond the basic quark model. Photoproduction has emerged as an attractive process to study hadron spectroscopy, due to the range of states accessible in new and planned experimental facilities, complimentary kinematics to other experiments where rescattering effects near thresholds are reduced, and advances in our theoretical understanding of these reactions. This white paper reviews the prospects for hadron spectroscopy from three major existing and proposed facilities: the current GlueX experiment, the planned Electron-Ion Collider, and a proposed JLab 24 GeV upgrade.

hep-ex↗
arXiv2021

Novel approaches in Hadron Spectroscopy

The last two decades have witnessed the discovery of a myriad of new and unexpected hadrons. The future holds more surprises for us, thanks to new-generation experiments. Understanding the signals and determining the properties of the states requires a parallel theoretical effort. To make full use of available and forthcoming data, a careful amplitude modeling is required, together with a sound treatment of the statistical uncertainties, and a systematic survey of the model dependencies. We review the contributions made by the Joint Physics Analysis Center to the field of hadron spectroscopy.

hep-ph↗
arXiv2019

Double Polarization Observables in Pentaquark Photoproduction

We investigate the properties of the hidden charm pentaquark-like resonances first observed by LHCb in 2015, by measuring the polarization transfer KLL between the incident photon and the outgoing proton in the exclusive photoproduction of J/psi near threshold. We present a first estimate of the sensitivity of this observable to the pentaquark photocouplings and hadronic branching ratios, and extend our predictions to the case of initial state helicity correlation ALL, using a polarized target. These results serve as a benchmark for the SBS experiment at Jefferson Lab, which proposes to measure for the first time the helicity correlations ALL and KLL in J/psi exclusive photoproduction, in order to determine the pentaquark photocouplings and branching ratios.

hep-ph↗
arXiv2018

Studying the Pc(4450) resonance in J/psi photoproduction off protons

The LHCb has reported the observation of a resonancelike structure, the Pc(4450), in the J/psi p invariant masses. In our work, we discuss the feasibility of detecting this structure in J/psi photoproduction, e.g. in the measurements that have been approved for the experiments in Hall A/C and in Hall B with CLAS12 at JLab. Also the GlueX Collaboration has already reported preliminary results. We take into account the experimental resolution effects, and perform a global fit to world J/psi photoproduction data in order to study the possibility of observing the Pc(4450) signal in future JLab data. We present a first estimate of the upper limit for the branching ratio of the Pc(4450) into the J/psi p channel, and we study the angular distributions of the differential cross sections. This will shed light on the nature and couplings of the Pc(4450) structure in the future photoproduction experiments.

hep-ph↗