The Exo(tic) Had(ron) Collaboration started in 2023 to explore all aspects of exotic hadron physics, from predictions within lattice QCD, through reliable extraction of their existence and properties from experimental data, to descriptions of their structure within phenomenological models.
News
Read allFirst observation of an exotic Reggeon
This newly submitted paper reports the first observation of an exotic Reggeon in high-energy scattering by the COMPASS experiment at CERN.
ExoHad researchers César Fernández Ramírez (UNED, co-PI), Giorgio Foti (Messina U., ExoHad PhD student), Nadine Hammoud (Barcelona U., ExoHad postdoc), Vincent Mahtieu (Barcelona U., co-PI), Gloria Montaña (Barcelona U., ExoHad postdoc), Robert J. Perry (MIT, ExoHad postdoc), Alessandro Pilloni (Messina U. & INFN Catania, co-PI), Arkaitz Rodas (ODU & JLab, Read more
First determination of vector and tensor couplings from polarized $\pi\Delta$ photoproduction
Coupling constants encode the underlying dynamics of the interacting hadrons and their determination forms a central goal of hadron physics. Many such couplings cannot be extracted from decay widths because the corresponding decays are kinematically forbidden.
Of these, the coupling of $N\Delta$ to mesons are of special interest due to their applications in a wide variety of studies. High-energy polarized photoproduction offers an alternative route, where these couplings appear as residues of Read more
Lattice QCD analysis of the H-dibaryon including left-hand-cut effects
Understanding exotic matter, composed of states that go beyond the conventional quark-antiquark and three-quark pictures, is a central goal of modern hadron physics. Lattice QCD offers a first-principles path to study these systems through finite-volume spectra, which can be related to scattering amplitudes. For several exotic candidates, long-range exchange mechanisms produce left-hand-cut branch points in the amplitudes close to the relevant energy region, requiring methods that incorporate Read more
Hidden-Strangeness Tetraquarks in the Dynamical Diquark Model
The dynamical diquark model describes multiquark exotic hadrons in terms of diquark components nucleated by heavy quarks, and successfully explains multiple features of hidden-charm and -bottom exotics. In a recent paper by Rich Lebed (ASU, co-PI) and Shahriyar Jafarzade (ASU, ExoHad postdoc), the model was applied to the marginally heavy case of hidden-strange states to probe whether mesons near 2 GeV with peculiar properties, such as $\phi(2170)$, $f_2(2340)$, and $X(2370)$, are possible Read more
Adjoint hadrons reveal the pattern of exotic hidden-heavy hadrons
An overarching explanation of exotic hadrons containing a heavy quark-antiquark pair has eluded the theoretical physics community for more than two decades. A recent study by Eric Braaten (OSU, co-PI) and Roberto Bruschini (OSU, ExoHad postdoc) points out that the pattern of these exotic hidden-heavy hadrons is largely determined by the spectrum of adjoint hadrons, which are the energy levels of quarks and gluons bound to a static color-octet source. The study explains exotic hidden-heavy Read more