Article
Physics, Multidisciplinary
Matteo Fael, Fabian Lange, Kay Schoenwald, Matthias Steinhauser
Summary: This article calculates the three-loop nonsinglet corrections to the photon-quark form factors, considering the virtuality of the photon and the quark mass. By combining the method of differential equations with expansions around regular and singular points, the results for the form factors are obtained with an accuracy of about eight to twelve digits in the whole kinematic range.
PHYSICAL REVIEW LETTERS
(2022)
Article
Astronomy & Astrophysics
J. Bluemlein, A. De Freitas, P. Marquard, N. Rana, C. Schneider
Summary: This study describes the quarkonic contributions to the three-loop heavy-quark form factors for vector, axial-vector, scalar, and pseudoscalar currents. These contributions can be solved analytically and expressed using various mathematical tools. By matching the expansions at the singularities and using differential equations, infinite series expansions for the form factors can be obtained. Some of the expansion coefficients can be determined analytically in terms of multiple zeta values and can be simplified into simpler mathematical expressions by resumming the infinite series. This analytical approach provides a deeper understanding of the massive form factors beyond numerical evaluation.
Article
Astronomy & Astrophysics
A. F. Krutov, V. E. Troitsky
Summary: In this study, we use a version of instant-form relativistic quantum mechanics to calculate the gravitational form factors of the pion, taking into account the gravitational structure of constituent quarks. The results show that the form factors are almost insensitive to the type of quark wave function model, similar to the case of the pion electromagnetic form factor.
Article
Astronomy & Astrophysics
Constantia Alexandrou, Simone Bacchio, Ian Cloet, Martha Constantinou, Joseph Delmar, Kyriakos Hadjiyiannakou, Giannis Koutsou, Colin Lauer, Alejandro Vaquero
Summary: We calculated the scalar, vector, and tensor form factors for the pion and kaon in lattice QCD. By using different parametrizations, we extracted the properties of the scalar, vector, and tensor and compared the differences between the pion and kaon form factors.
Article
Astronomy & Astrophysics
Laurence J. Cooper, Christine T. H. Davies, Matthew Wingate
Summary: We present the first lattice QCD calculations of weak matrix elements and analyze several decays. The results provide important parameters for these decays.
Article
Astronomy & Astrophysics
Parada T. P. Hutauruk, Seung-il Nam
Summary: This paper investigates the gluon and valence quark distributions in the pion and kaon in nuclear medium as well as in vacuum, finding that the medium gluon and valence-quark distributions for the kaon increase significantly with respect to the densities. The vacuum gluon distribution for the kaon is smaller than that for the pion, consistent with other theoretical predictions up to the saturation density in nuclear medium.
Article
Astronomy & Astrophysics
Mingyang Yang, Ping Wang
Summary: In this study, the sea quark contributions to the electromagnetic form factors of Sigma baryons were investigated using nonlocal chiral effective theory. The calculations involved both octet and decuplet intermediate states. It was found that G(Sigma-)(u) and G(Sigma+)(d) are significantly larger than the strange form factors of nucleons, making them priority observables for examining sea quark contributions to baryon structure. The determination of the sign of these pure sea quark contributions is expected to be less challenging in lattice simulations. Additionally, the comparison of the light sea quark form factors in Sigma(0), which are identical, with those in protons provides meaningful insights and references for further research.
Article
Physics, Particles & Fields
Shan Cheng, Yao-hui Ju, Qin Qin, Fu-sheng Yu
Summary: This study calculates the QCD LCSRs of D-s*->phi helicity form factors and discusses the potential of discovering exclusive D-s* weak decays. The results show that these channels are promising for the first experimental observation of weak decays of a vector meson, providing a new playground for precision test of the standard model.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Astronomy & Astrophysics
Jung-Min Suh, Hyun-Chul Kim
Summary: In this study, the axial-vector transition form factors of the lowest-lying singly heavy baryons are investigated using the chiral quark-soliton model. Numerical results are presented and compared with experimental data.
Article
Astronomy & Astrophysics
X. Y. Liu, A. Limphirat, K. Xu, Z. Zhao, K. Khosonthongkee, Y. Yan
Summary: We study the axial transition form factors GB'B'A(Q2) and the axial charges gB'B' A of the octet baryons in the perturbative chiral quark model with the inclusion of both ground and excited states in the intermediate quark propagators. The results from the perturbative chiral quark model are in good agreement with experimental data and lattice-QCD values. The study reveals that the dipolelike behavior of GB'B'A(Q2) is primarily caused by the three-quark core, with the contribution from the meson cloud and excited-state quark propagator being limited.
Article
Physics, Multidisciplinary
S. A. Franchino-Vinas
Summary: In this article, we study the resummed expressions for the trace of a Laplace operator's heat-kernel with a potential and Dirichlet semitransparent boundary conditions on a surface in flat space. We derive resummed expressions that correspond to the first and second order expansion of the heat-kernel. These results are applied to calculate the bulk and surface form factors of a scalar quantum field theory in four dimensions with a Yukawa coupling to a background. Furthermore, we explore the connection between the heat-kernels for Dirichlet semitransparent, Dirichlet, and Robin boundary conditions.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2023)
Article
Physics, Particles & Fields
Yu-Ji Shi, Chien-Yeah Seng, Feng-Kun Guo, Bastian Kubis, Ulf-G Meissner, Wei Wang
Summary: This study provides a comprehensive analysis of form factors for two light pseudoscalar mesons induced by scalar, vector, and tensor quark operators. By combining unitarized chiral perturbation theory and dispersion relations, it updates existing results and explores previously unstudied areas, particularly focusing on the two-meson tensor form factors within unitarized chiral perturbation theory. The applications of these form factors for low-energy phenomena and in searches for physics beyond the Standard Model are also discussed.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Physics, Nuclear
Z. Y. Gao, P. Wang, M. Y. Yang
Summary: The nonlocal chiral effective theory is used to study the electromagnetic and strange form factors of nucleons, including bubble and tadpole diagrams in the calculation. The electromagnetic form factors are close to the results without the contributions of bubble and tadpole diagrams as long as the low energy constants c(1) and c(2) are properly chosen, while the magnitudes of strange form factors become larger. The electromagnetic form factors are in good agreement with experimental results, whereas the magnitudes of strange form factors are larger than lattice data.
Article
Astronomy & Astrophysics
G. Martinelli, S. Simula, L. Vittorio
Summary: This study provides the first nonperturbative determination of the hadronic susceptibilities that constrain the form factors in the semileptonic B -> D-(*())l nu(l) transitions. By evaluating moments of suitable two-point correlation functions obtained on the lattice, the study calculates the longitudinal and transverse susceptibilities of vector and axial-vector polarization functions at different pion masses and lattice spacings. The physical values of the scalar, vector, pseudoscalar, and axial susceptibilities are obtained using the Extended Twisted Mass Collaboration (ETMC) ratio method.
Article
Astronomy & Astrophysics
Matteo Fael, Fabian Lange, Kay Schoenwald, Matthias Steinhauser
Summary: In this study, we investigate quantum chromodynamics with external currents and compute three-loop corrections with massive quarks taken into account. We develop a seminumerical method that combines expansions and matching in order to improve precision across the entire kinematic range. Our results are presented as a combination of series expansions and interpolation functions, making them easily applicable in practical scenarios.
Article
Physics, Nuclear
G. Ramalho
EUROPEAN PHYSICAL JOURNAL A
(2019)
Article
Astronomy & Astrophysics
J. J. Cobos-Martinez, K. Tsushima, G. Krein, A. W. Thomas
Article
Physics, Multidisciplinary
K. Tsushima
Summary: This study investigates the magnetic moments of baryons with nonzero light quarks in symmetric nuclear matter using the QMC model, and evaluates medium modifications of the magnetic moments. The results show that the QMC model aligns well with experimental data.
PROGRESS OF THEORETICAL AND EXPERIMENTAL PHYSICS
(2022)
Article
Astronomy & Astrophysics
G. Ramalho
Summary: Complete calculations of the electromagnetic form factors of the Omega(-) have been presented in both spacelike and timelike regions. The analyses are conducted within the covariant spectator quark model, and the results are compared with lattice QCD data and experimental data from CLEO. The impact of large-Q(2) correlations and possible solutions are also examined.
Article
Astronomy & Astrophysics
G. Ramalho
Article
Astronomy & Astrophysics
G. Ramalho, M. T. Pena
Article
Astronomy & Astrophysics
G. Ramalho, M. T. Pena, K. Tsushima
Article
Astronomy & Astrophysics
G. Ramalho
Article
Astronomy & Astrophysics
Parada T. P. Hutauruk, J. J. Cobos-Martinez, Yongseok Oh, K. Tsushima
Article
Astronomy & Astrophysics
S. X. Nakamura, K. Tsushima
Article
Astronomy & Astrophysics
G. Ramalho, J. P. B. C. de Melo, K. Tsushima
Article
Astronomy & Astrophysics
K. Tsushima
Article
Physics, Nuclear
Parada T. P. Hutauruk, Yongseok Oh, K. Tsushima
