Hadron Spectra, Decays and Scattering Properties Within Basis Light Front Quantization

Abstract

We survey recent progress in calculating properties of the electron and hadrons within the Basis Light Front Quantization (BLFQ) approach. We include applications to electromagnetic and strong scattering processes in relativistic heavy ion collisions. We present an initial investigation into the glueball states by applying BLFQ with multigluon sectors, introducing future research possibilities on multi-quark and multi-gluon systems.Static and dynamic properties of the hadrons, including finite nuclei, are the foci of major theoretical and experimental efforts in the nuclear physics community. Interesting topics include the nonperturbative roles of the constituent quarks and gluons in the manifested phenomena such as the distribution of angular momenta, pileup of gluon distributions at low longitudinal momentum fractions, electromagnetic moments/transitions, emergence of exotic structures beyond the simple constituent models and diffractive production cross sections. Our BLFQ framework addresses these phenomena with a relativistic treatment of the Hamiltonian developed with input from the QCD Lagrangian supplemented by confining terms. We solve for the mass eigenstates and their light-front amplitudes in the Basis Light Front Quantization (BLFQ) approach [1; 2; 3]. The light front amplitudes bridge our theory with observables such as form factors, decay constants and those in time-dependent scattering processes [4; 5]. Specifically, our Hamiltonian framework allows the study of time-dependent phenomena using the time-dependent Basis Light Front Quantization (tBLFQ) approach. We gradually improve the tBLFQ results by replacing modeled background fields with those obtained directly from QCD.In this article we overview recent developments, expanding our report of last year [6], and survey prospects for the near future. For additional perspectives of recent research and future prospects in lightfront Hamiltonian theory, see Refs. [7; 8] and references therein. Basis Light-Front QuantizationThe non-perturbative solution of quantum field theory within the Hamiltonian framework has a rich history. Pioneering efforts addressed the mass eigenstate problem of the light-front Hamiltonian in the discretized plane-wave basis [9] called Discretized Light-Cone Quantization (DLCQ), whose application continues to the present [8]. In order to better address the conserved total angular momentum projection, to improve numerical convergence when confining interactions are present and to facilitate multi-fermion and multiboson applications, we introduced BLFQ by adapting successful methods from ab initio nuclear structure theory [1].We aim to solve the light-front mass eigenvalue problem expressed as,where the operatorsP + andP − are the longitudinal momentum (+) and the light-front quantized Hamiltonian (−), whileP ⊥ represents the transverse momentum. The invariant-mass (M ) spectrum and lightfront state vectors |ψ h result from diagonalizing Eq. 1 in a suitable matrix representation of the effective Hamiltonian. Expressing the state...

Spectroscopy of light ${{N^*}}$ baryons

“…We can also expect the new results from the analysis project like EBAC, Julich, SAID, MAID, etc. Many theoretical studies are the phenomenological tool to investigate the excited resonances of nucleons; various quark models [21][22][23][24][25][26][27][28], Basis Light Front Quantization (BLFQ) approach [29], BnGa partial wave analysis [30], chiral Lagrangian theory [31], Fadeev approach [32,33] Lattice QCD [34][35][36],etc.…”

All-charm tetraquark in front form dynamics

“…This important, but rather technical topic is described in more detail in the Appendix. Similar basis spaces restricted to include only color singlets have been implemented for a BLFQ treatment of glueballs with Fock spaces having up to six gluons [66].…”

Basis light-front quantization for a chiral nucleon-pion Lagrangian

“…BLFQ is a non-perturbative, ab initio method, which treats relativistic quantum field theory via the Hamiltonian approach within the light-front (LF) formalism. BLFQ has been shown to be a promising tool in a range of applications [5], such as the electron anomalous magnetic moment [6,7], the positronium spectrum [8], and the heavy quarkonium structure and radiative transitions [9][10][11][12][13]. More recently, BLFQ has been applied successfully to the properties of the light mesons [14], which are then extended to experimentrelevant scales by perturbative QCD evolution [15].…”