We use a version of the instant-form relativistic quantum mechanics of composite systems to obtain the gravitational form factors of the pion in a common approach to its electroweak and gravitational properties. In the preceding work [arXiv:2010.11640] we formulated the mathematical background, presented the principal scheme of calculation and testified the obtained qualitative results to satisfy the general constraints given by the principles of the theory of hadron structure. In the present work we give the detailed calculation of the gravitational form factors in large range of momentum transfer, their static limits and the slopes at zero value, the mean-square mass and mechanical radii of the pion. Now we take into account the qravitational structure of the constituent quarks. We show that the results are almost insensitive to the type of the model two-quark wave function in a close analogy to the case of the pion electromagnetic form factor. We present a correct calculation of the form factor $D$ and corresponding matrix element of the energy-momentum tensor, going beyond the scope of the modified impulse approximation. Most of the parameters that we use for the calculation had been fixed even earlier in our works on the pion electromagnetic form factors. The only free parameter is the $D$-term of the constituent quark, which we fix by fitting the result for the slope at zero of the normalized to pion $D$-term form factor $D$ of pion, to a choosen experimental value.
We extend our relativistic theory of electroweak properties of composite systems to describe simultaneously the gravitational form factors of hadrons. The approach is based on a version of the instant-form relativistic quantum mechanics and makes use of the modified impulse approximation. We exploit the general method of the relativistic invariant parametrizaton of local operators to write the energy-momentum tensor of a particle with an arbitrary spin. We use the obtained results to calculate the gravitational form factors of the pion assuming point-like constituent quarks. All but one parame…
Transition from a relativistic constituent-quark model to the quantum-chromodynamical asymptotics: a quantitative description of the pion electromagnetic form factor at intermediate values of the momentum transfer
Composite Hybrid Inflation : Primordial Black Holes and Stochastic Gravitational Waves
Sorbonne Université（索邦大学）；CNRS（法国国家科学研究中心）；Yonsei University（延世大学）；Université Claude Bernard Lyon 1（里昂第一大学）；IP2I（伊恩·皮埃尔·加朗物理研究所）；University of Johannesburg（约翰内斯堡大学）；Korea Institute for Advanced Study（韩国高等研究院）；Kavli Institute for the Physics and Mathematics of the Universe（卡弗里宇宙物理学和数学研究所）；The University of Tokyo（东京大学）；Tongji University（同济大学）
Double integral representation in the invariant masses of a composite system and nonperturbative calculation of the asymptotics of light-meson electromagnetic form factors
Samara State Technical University（萨马拉国立技术大学）；Lyceum 135 - basic school of the Russian Academy of Sciences（俄罗斯科学院第135中学）；D.V. Skobeltsyn Institute of Nuclear Physics, M.V. Lomonosov Moscow State University（莫斯科国立大学D.V.斯科别尔琴核物理研究所）
We investigate the possibility of charged pion condensation in the presence of parallel rotation and magnetic field within the Nambu--Jona-Lasinio model with quarks as the fundamental degrees of freedom. Previous study based on non-interacting Klein-Gordon theory for pions showed that the charged pions will undergo Bose-Einstein condensation under this circumstance [Y. Liu and I. Zahed, Phys. Rev. Lett. ${\bf 120}$, 032001 (2018)]. In this work, we take into account the internal quark structures of charged pions self-consistently through quark polarization loops in an interacting theory, i.e.,…
We study the electromagnetic form factors of the lowest-lying singly heavy baryons with spin 1/2 within the framework of the chiral quark-soliton model, focusing on the comparison with recent lattice data. To compare the present results quantitatively with the lattice data, it is essential to treat the pion mass as a variable parameter, i.e., to employ the unphysical values of the pion mass, which are used in lattice calculations. While the results with the physical value of the pion mass fall off faster than those from the lattice calculations as the momentum transfer increases, the extrapola…
We use the linear sigma model with quarks to find the magnetic field-induced modifications to the neutral pion mass at one-loop level. The magnetic field effects are introduced by using charged particle propagators in the presence of a magnetic background in the strong field regime. We show that when accounting for the effects of the magnetic field on the model couplings, the vacuum sigma field and the neutral pion self-energy, the neutral pion mass decreases monotonically as a function of the field strength. We find an excellent qualitative and quantitative agreement with recent lattice QCD c…
