Novel algebraic methods are applied to quarkonium spectrum in the unquenched quark model, which incorporates the coupling between $Q\bar Q$ and $(Q\bar q)(q\bar Q)$ degrees of freedom. Working in the discrete position basis, the calculation of matrix elements simplifies considerably in comparison to other approaches, leading not only to improvements in computational efficiency, but also more...
One of the greatest unsolved mysteries of modern physics is the observation of invisible yet gravitationally attractive dark matter. The dark photon $A^\prime$ is a proposed new U(1) gauge boson that offers a unique vector portal between the Standard Model and the dark sector.
This poster presents a new, ongoing search at BESIII for the creation and visible decay of a massive dark photon via...
We plan to perform missing-mass spectroscopy of deeply bound pionic Xe atoms using an inverse kinematics reaction. So far, the (d, ${}^{3}$He) reaction in normal kinematics has been employed to measure excitation-energy spectra of pionic states in Sn and Pb isotopes [1−5]. In the new experiment, we adopt, for the first time, the inverse-kinematics (${}^{136}$Xe, ${}^{3}$He) reaction for the...
Axions as dark matter candidates may be produced via an infrared freeze-in mechanism from heavy meson decays in the early universe. In this scenario, higher-order corrections to the axion production rate contain infrared divergences. We demonstrate how holomorphic cutting rules, together with the Kinoshita-Lee-Nauenberg theorem, allow one to identify the minimal set of contributions required...
Using a symmetry-preserving truncation of the quantum field equations describing hadron properties, parameter-free predictions are delivered for pion and kaon elastic electromagnetic form factors, $F_{P=\pi,K}$, thereby unifying them with kindred results for nucleon elastic electromagnetic form factors.
Regarding positive-charge states, the analysis stresses that the presence of scaling...
Orbital angular momentum (OAM) is not a Poincar\'e invariant quantity; so, its value is observer dependent. Notwithstanding that, in quantum chromodynamics, a Poincar\'e-invariant theory, OAM is part of every hadron wave function. Using continuum Schwinger function methods, we elucidate both the subjective character of in-hadron OAM and expose some of its impacts on pion and kaon structure...
We investigate axion-meson mixing and its consequences for low-energy scattering and decay processes within the framework of Chiral Perturbation Theory ($\chi PT$). Starting from the most general effective Lagrangian, we derive mixing terms between a general axion-like-particle (ALP) and light pseudoscalar mesons and compute their impact on 4-body, axion-meson amplitudes, including isospin...
We study the effect of a finite volume for pion-pion scattering within Chiral Perturbation Theory (ChPT) and the Inverse Amplitude Method (IAM) in a box for different boost's. Our full ChPT calculation takes into account the discretization not only in the $s$-channel loops but also in the $t,u$- channels and tadpole contributions. Hence, not only the unitarity right-hand cut but also the...
Renewed interest in the structure and internal properties of quarkonia and quarkonium-like states has prompted further investigation. We will analyse the radiative transitions of specific $Q \bar Q$ states within the light-front wave function framework. Particular attention is given to higher excited states, which may provide insight into possible exotic states. Our model applies the Melosh...
One or two $D_0^*$ resonances with strangeness $S=0$, isospin $I=1/2$ dynamically generated in pseudo-scalar meson octet and heavy mesons scattering are still a puzzle. In this talk, I will present that there are two $D_0^*$ resonances generated by ChPT up to NLO. The LECs of the interaction are constrained by the energy levels simulated by LQCD in $(S,I)=(0,1/2)$, $(1,0)$, $(-1,0)$, and...
The High-Acceptance Di-Electron Spectrometer (HADES) operates at the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt with pion, proton and heavy-ion beams provided by the synchrotron SIS-18 [1]. In February 2022, the HADES collaboration conducted measurements with proton beam at 4.5 GeV kinetic energy using the upgraded setup within the FAIR-Phase0 program collecting statistics of 6...
In this investigation we show that, similarly to the low density nuclear liquid-gas phase transition, thermodynamic instabilities and, consequently, a pure hadronic phase transition can occur in regime of finite temperature and dense baryon matter. The analysis is performed by means of an effective relativistic mean-field model with the inclusion of hyperons, Δ-isobars, and the lightest...
Studies of the axial-vector $f_1(1285)$ meson production at near threshold energies with HADES is particularly interesting because of its production mechanism. It involves vector meson fusion VV $(\rho\rho, \omega\omega)\rightarrow f_1$ which provide information about the $\rho\rho f_1$ and $ \omega\omega f_1$ coupling constants. This in turn is very important for calculations of hadronic...
The study of the baryon-baryon interaction is a basic tool to investigate the strong interaction. Especially in the strangeness $S = -2$ sector the available data are strongly limited. Most studies in this field were devoted to the search for the $H$-particle, a $(B = 2, S = -2)$ system with the quark configuration $(uuddss)$ first proposed by Jaffe [1]. Experimentally, $S = -2$ baryonic...
High-energy nuclear collisions provide important information on the characteristics of strongly interacting matter at extreme temperatures and densities. Among the most used experimental observables that provides valuable insight into the system dynamics and the kinetic freeze-out stage are the transverse momentum spectra of the produced particles. We present a study of the mean transverse...
The production of $\eta\pi$ and $\eta^\prime\pi$ has been studied by COMPASS using a ${190}{\,\text{GeV}/c}$ pion beam from CERN SPS. The corresponding partial-wave decompositions (PWD) show a pronounced peak in the exotic $J^{PC}=1^{-+}$ $P$-wave at around ${1.4}{\,\text{GeV}/c^2}$ in the $\eta\pi$ channel and around ${1.65}{\,\text{GeV}/c^2}$ in the $\eta^\prime\pi$ channel. In the $\eta\pi$...
We present two recently patented methods for estimating hadron
beam energy and energy spread. The measurement data supporting these
methods were acquired at The Henryk Niewodniczanski Institute of Nuclear
Physics Polish Academy of Science in Krakow. The collected datasets from
C-230 at Cyclotron Center Bronowice (CCB) and cyclotron AIC-144
demonstrate the practical effectiveness of the...
