Article
Multidisciplinary Sciences
Reinhard Alkofer
Summary: Dynamical chiral symmetry breaking (D & chi;SB) is an important concept in understanding hadron physics, particularly the generation of constituent quark masses. However, when considering higher n-point functions, the role of the quark-gluon vertex becomes more complex, as it both signals and drives D & chi;SB. Recent results suggest that D & chi;SB in QCD is located close to the critical point, making it a delicate effect.
Article
Astronomy & Astrophysics
Marcela Pelaez, Urko Reinosa, Julien Serreau, Matthieu Tissier, Nicolas Wschebor
Summary: By introducing an approximation scheme, we are able to incorporate the realistic running of parameters and study the unquenched gluon and ghost propagators to a first nontrivial order, allowing for a more stringent test of our approach with available lattice data. Our results for various two-point functions compare well with lattice data, while the model parameters are strongly constrained.
Article
Astronomy & Astrophysics
L. Albino, A. Bashir, A. J. Mizher, A. Raya
Summary: This study investigates the effects of a refined electron-photon vertex on the dynamical breaking of chiral symmetry in reduced quantum electrodynamics. The constructed educated ansatz for the vertex satisfies the required discrete symmetries and reproduces its perturbative limit in the weak coupling regime. The dynamically generated electron mass and its dependence on electromagnetic coupling are found to follow Miransky scaling law.
Article
Astronomy & Astrophysics
D. Fiorentini, D. R. Junior, L. E. Oxman, G. M. Simoes, R. F. Sobreiro
Summary: Based on a new procedure, it is argued that Singer's theorem suggests the existence of a Yang-Mills ensemble, with gauge fields mapped into an auxiliary field space to determine sectors labeled by center vortices. The study provides examples of configurations belonging to different sectors, discusses the importance of non-Abelian degrees of freedom, and shows that the examples are free from Gribov copies.
Article
Astronomy & Astrophysics
Pianpian Qin, Zhan Bai, Muyang Chen, Si-xue Qin
Summary: This paper investigates the in-hadron condensates for flavor-symmetric mesons in pseudoscalar and vector channels within the Dyson-Schwinger equations framework. The efficiency of the in-hadron condensates in describing the effects of dynamical chiral symmetry breaking is confirmed from both global and structural perspectives. Partial wave analysis suggests that pi(1300) is a radial excitation dominated by s waves, while further studies are needed for rho(1450) beyond the investigated truncation. This work provides new insights into the studies of hadron properties using partial wave analysis for in-hadron condensates.
Article
Physics, Nuclear
Aftab Ahmad
Summary: This study explores the effects of external electric and magnetic fields on the phase transitions in QCD, focusing on chiral symmetry breaking/restoration and confinement/deconfinement. Using a unified formalism based on Schwinger-Dyson equations and vector-vector contact interaction models, the study identifies various phenomena such as magnetic catalysis, electric chiral rotation, and inverse electric/magnetic catalysis in different field conditions at finite temperature. The findings are consistent with predictions from lattice simulations and effective models in QCD.
Article
Astronomy & Astrophysics
Fei Gao, Joannis Papavassiliou, Jan M. Pawlowski
Summary: In this study, a comprehensive investigation of the quark sector of 2 + 1 flavor QCD was conducted using a self-consistent treatment of the Schwinger-Dyson equations for the quark propagator and the full quark-gluon vertex. The hierarchy among the vertex form factors was established, with only three dominant ones identified. The quark propagator components obtained from this approach showed excellent agreement with results from other methods and simulations, demonstrating the versatility and reliability of the present approach.
Article
Astronomy & Astrophysics
Lei Chang, Minghui Ding
Summary: It is found that the rainbow approximation is suitable for the gap equation, while the ladder approximation and modified-ladder approximation are effective truncation schemes for the Bethe-Salpeter equation. When studying the pion, it is observed that the pion mass and decay constant are equivalent in both the ladder and modified-ladder approximations, despite apparent differences in Bethe-Salpeter amplitudes. The justification for the modified-ladder approximation is examined using the Gell-Mann-Oakes-Renner relation.
Article
Astronomy & Astrophysics
Chen Chen, Christian S. Fischer, Craig D. Roberts, Jorge Segovia
Summary: This study presents a continuum quark + diquark approach to solve the nucleon bound-state problem in relativistic quantum field theory and provides parameter-free predictions for the nucleon axial and induced pseudoscalar form factors. By constructing the necessary couplings between the external current and the building blocks of the nucleon consistently, the partial conservation of the axial-vector current and the associated Goldberger-Treiman relation are satisfied. The results show accurate descriptions of the pointwise behavior of the axial form factor and reliable estimates of the pseudoscalar form factor and pion-nucleon coupling constant.
Article
Physics, Nuclear
Yin-Zhen Xu, Si-Xue Qin, Hong-Shi Zong
Summary: We study chiral symmetry restoration by analyzing the thermal properties of QCD's(pseudo-) Goldstone bosons, such as the pion. The properties of the mesons are obtained from the spectral densities of mesonic imaginary-time correlation functions. In the chiral limit, the pion and its partner sigma degenerate at the critical temperature. At temperatures greater than or similar to Tc, the pion dissociates rapidly, indicating the deconfinement phase transition. Beyond the chiral limit, the pion dissociation temperature can be used to define the pseudo-critical temperature of the chiral phase crossover, which is consistent with the maximum point of chiral susceptibility. A similar analysis for kaon and pseudoscalar s (s) over bar suggests that heavy mesons may survive above Tc.
Article
Astronomy & Astrophysics
Ling-feng Chen, Zhan Bai, Fei Gao, Yu-xin Liu
Summary: By solving the Dyson-Schwinger equations and analyzing the resulting mass function, the study computes the quark condensate beyond the chiral limit with a cutoff independent definition. The well-defined condensate is then analyzed for its evolution and susceptibility with the current quark mass, showing a critical mass at about QCD that defines a transition boundary for internal hadron dynamics.
Article
Astronomy & Astrophysics
A. C. Aguilar, C. O. Ambrosio, F. De Soto, M. N. Ferreira, B. M. Oliveira, J. Papavassiliou, J. Rodriguez-Quintero
Summary: In this study, the dynamics of the ghost sector in quenched QCD in the Landau gauge have been investigated using large-volume lattice simulations as key inputs. The results show excellent agreement between numerical treatments and lattice data, indicating a high level of consistency in both physical concepts and computational schemes.
Article
Materials Science, Multidisciplinary
Pei-Lin Yin, Heng Chen, Jing Yu
Summary: In this work, we quantitatively explore the effects of a finite gauge boson mass on dynamical mass generation and the chiral phase transition in thermal QED3. By numerically solving the Dyson-Schwinger equations considering the wave function renormalization and the spatial part of the boson propagator, we compute the chiral condensate and some thermodynamic quantities. The results indicate that the wave function renormalization and the spatial part of the boson propagator are crucial for the numerical solutions and the critical temperature value, and that the chiral phase transition is a second order one. Furthermore, the decrease in critical temperature with increasing gauge boson mass confirms the weakening of fermion interactions and the suppression of dynamical mass generation.
RESULTS IN PHYSICS
(2023)
Article
Astronomy & Astrophysics
Zanbin Xing, Khepani Raya, Lei Chang
Summary: The study focuses on the symmetry-preserving treatment of mesons by establishing a connection between the quark gap equation and meson Bethe-Salpeter equation. By utilizing vector and axial-vector Ward-Green-Takahashi identities, a two-body Bethe-Salpeter kernel is constructed to analyze the structure of the quark-photon vertex and various properties of rho mesons.
Article
Astronomy & Astrophysics
Chao-Hsiang Sheu, Mikhail Shifman
Summary: The study investigates the pattern of chiral symmetry breaking in the R3 x S1 L model and derives the implications for R4 physics using a double-trace deformation. The stability of center-symmetric vacua is ensured. By analyzing the instanton-monopole operators, the existence of adjoint chiral condensate in R4 is confirmed, along with the spontaneous breaking of the SUoNcTHORN gauge symmetry.
Article
Physics, Multidisciplinary
Daniele Binosi
Summary: Emergent Hadron Mass (EHM) is a mechanism that explains the masses of hadrons and is intimately connected to their origin or confinement. EHM has become a key research focus for understanding strong interactions, utilizing Dyson-Schwinger equations for investigation.
Article
Astronomy & Astrophysics
Lei Chang, Fei Gao, Craig D. Roberts
Summary: This article uses an algebraic Ansatz to calculate the proton's wave function and distribution functions, and compares it with the pion. The findings suggest some factors that may explain the differences in proton properties.
Article
Physics, Nuclear
Zhu-Fang Cui, Daniele Binosi, Craig D. Roberts, Sebastian M. Schmidt
Summary: Radii are simple Poincare-invariant properties associated with hadrons and light nuclei. Recent measurements and analyses have shown uncertainties and imprecisions in the radii of the proton, pion, kaon, and deuteron. The statistical Schlessinger point method (SPM), independent of practitioner-induced bias, provides an objective expression of the information contained in any data and is applicable to diverse systems and observables.
Article
Astronomy & Astrophysics
Ya Lu, Lei Chang, Khepani Raya, Craig D. Roberts, Jose Rodriguez-Quintero
Summary: This study uses consistent determination of valence distribution functions (DFs) for proton and pion at the same hadron scale, and presents a unified prediction for all DFs including valence, glue, and four-flavour-separated sea. The results show that while identifiable parton classes carry the same hadron light-front momentum fractions for both proton and pion at any scale, the behavior of DFs is strongly dependent on the hadron.
Article
Astronomy & Astrophysics
F. Pinto-Gomez, F. De Soto, M. N. Ferreira, J. Papavassiliou, J. Rodriguez-Quintero
Summary: We present new results for the three-gluon vertex obtained from a large-scale lattice simulation in the Landau gauge. The simulation evaluates the transversely projected vertex using a special tensorial basis, with form factors parametrized in terms of Bose-symmetric variables. Interestingly, the form factors primarily depend on a single kinematic variable, the sum of the squares of the three incoming four-momenta. This property, known as planar degeneracy, allows for a simplified and compact description of the data, suitable for future numerical applications. Confirming this property through a detailed study of specific configurations, we find that a semi-perturbative analysis accurately reproduces the lattice findings when a gluon mass is included to eliminate spurious divergences. (c) 2023 Published by Elsevier B.V. This is an open access article under the CC BY license (http:// creativecommons .org /licenses /by /4 .0/). Funded by SCOAP3.
Article
Astronomy & Astrophysics
Daniele Binosi, Alessandro Pilloni, Ralf-Arno Tripolt
Summary: In this study, a model-independent reconstruction method is applied to experimental data to identify complex poles of overlapping resonances. The algorithm utilizes the Schlessinger Point Method and interpolates data points using a continued-fraction expression. The statistical uncertainties of experimental data are propagated with resampling. The feasibility of the method is demonstrated by applying it to the S-wave J/ψ -> γg0g0 decay, where the f0(1500), f0(1710), and f0(2020) scalar states are identified from BESIII data. The results are in reasonable agreement with recent studies, indicating the potential of the proposed method as a model-independent alternative for determining resonance poles solely based on available experimental data.
Article
Astronomy & Astrophysics
A. C. Aguilar, F. De Soto, M. N. Ferreira, J. Papavassiliou, F. Pinto-Gomez, C. D. Roberts, J. Rodriguez-Quintero
Summary: Continuum and lattice analyses have discovered a mass-scale in the gluon two-point Schwinger function, indicating the presence of a Schwinger mechanism for gauge boson mass generation in quantum chromodynamics (QCD). By using numerical simulations of lattice-regularised QCD, the researchers established with high confidence the existence of a dynamically-generated, massless, colour-carrying, scalar gluon+gluon correlation, confirming the conjectured origin of the gluon mass scale.
Article
Astronomy & Astrophysics
Zhu-Fang Cui, Daniele Binosi, Craig D. Roberts, Sebastian M. Schmidt, D. N. Triantafyllopoulos
Summary: Theory suggests that the t-channel exchange of odderon may generate differences between pp and pp over bar cross-sections. Through robust comparisons using a mathematical approach, we find significant differences between pp and pp over bar elastic differential cross-sections. Combining these results with other experiment-theory comparisons, we obtain a significant signal for the existence of odderon at the (4.0 - 5.2)sigma level.
Review
Astronomy & Astrophysics
Mauricio Narciso Ferreira, Joannis Papavassiliou
Summary: In this work, we review some significant progress in the investigation of the QCD gauge sector using the continuum Schwinger function methods and lattice simulations. These non-perturbative phenomena, such as the generation of a gluon mass, taming of the Landau pole, stabilization of the gauge coupling, and infrared suppression of the three-gluon vertex, play a crucial role in maintaining the internal consistency of the theory.
Article
Astronomy & Astrophysics
Zanbin Xing, Minghui Ding, Lei Chang
Summary: We present a novel approach to calculate the gravitational form factor of pion using the ladder approximation of the Bethe-Salpeter equation with contact interactions. A key aspect of this approach is the symmetry-preserving treatment of the dressed pi pi amplitude, which reveals the contributions from intrinsic quarks and bound states, the latter being essential for the D-term of pion in the soft-pion limit. The method we propose in this study can be applied to numerous processes of significance in physics.
Article
Astronomy & Astrophysics
Zanbin Xing, Lei Chang
Summary: This work proposes a symmetry preserving regularization procedure for the contact interaction model. This regularization follows consistency conditions to maintain gauge symmetry. Proofs for preserving the Ward-Takahashi identities are provided, and loop integrals are systematically computed. Application examples of kaon electromagnetic form factor and Kl3 transition form factor demonstrate self-consistent results. The proposed regularization properly handles divergences, allowing more focus on physical discussions.
Article
Physics, Particles & Fields
A. C. Aguilar, M. N. Ferreira, D. Ibanez, B. M. Oliveira, J. Papavassiliou
Summary: In this study, we show through explicit calculations that the same distinct realization of the Slavnov-Taylor identity persists in the case of the background three-gluon vertex. The analysis is carried out at the level of the exact Schwinger-Dyson equation for this vertex, without any truncations or simplifying assumptions. The final result is obtained through extensive cancellations, without the need for explicit integrations. Additionally, we highlight that background Ward identities can be obtained by replacing derivatives of propagators with zero-momentum background-gluon insertions, similar to standard properties of Abelian gauge theories. Finally, we briefly discuss potential applications of these results.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Physics, Particles & Fields
A. C. Aguilar, M. N. Ferreira, B. M. Oliveira, J. Papavassiliou
Summary: In this study, we investigate a special Schwinger-Dyson equation in the context of a pure SU(3) Yang-Mills theory using the background field method. We focus on the vertex that describes the interaction between two background gluons and a ghost-antighost pair. By exploiting the background gauge invariance, we find that this vertex satisfies a simple Slavnov-Taylor identity that is unaffected by the ghost sector. In the limit where all momenta vanish, we obtain the exact form of this vertex from the corresponding Ward identity. Moreover, we demonstrate that this special result can be reproduced using the Schwinger-Dyson equation, taking advantage of Taylor's theorem and the specific relations in the background field method. This information allows us to determine the truncation error associated with two different truncation schemes and assess the potential benefit of using lattice data for the ghost dressing function.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Physics, Particles & Fields
B. Acharya, J. Alexandre, P. Benes, B. Bergmann, S. Bertolucci, A. Bevan, R. Bhattacharyya, H. Branzas, P. Burian, M. Campbell, S. Cecchini, Y. M. Cho, M. de Montigny, A. De Roeck, J. R. Ellis, M. ElSawy, M. Fairbairn, D. Felea, M. Frank, J. Hays, A. M. Hirt, P. Q. Hung, J. Janecek, M. Kalliokoski, A. Korzenev, D. H. Lacarrere, C. Leroy, G. Levi, A. Lionti, A. Margiotta, R. Maselek, A. Maulik, N. Mauri, N. E. Mavromatos, E. Musumeci, M. Mieskolainen, L. Millward, V. A. Mitsou, R. Orava, I Ostrovskiy, P-P Ouimet, J. Papavassiliou, B. Parker, L. Patrizii, G. E. Pavalas, J. L. Pinfold, L. A. Popa, V Popa, M. Pozzato, S. Pospisil, A. Rajantie, R. Ruiz de Austri, Z. Sahnoun, M. Sakellariadou, K. Sakurai, A. Santra, S. Sarkar, G. Semenoff, A. Shaa, G. Sirri, K. Sliwa, R. Soluk, M. Spurio, M. Staelens, M. Suk, M. Tenti, V Togo, A. Upreti, V. Vento, O. Vives
Summary: This study presents a search for highly electrically charged objects and magnetic monopoles using data collected by the MoEDAL detector at the LHC. The results provide constraints on the properties of these objects, such as their mass and charge.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Astronomy & Astrophysics
A. C. Aguilar, M. N. Ferreira, J. Papavassiliou
Summary: This study presents a detailed derivation of the non-Abelian Ward identity obeyed by the pole-free part of the three-gluon vertex in the soft gluon limit, and determines the displacement that the onset of the Schwinger mechanism produces to the standard result. The results obtained through two independent methods are in excellent coincidence, providing a self-consistency check for the entire approach. The statistical significance of the resulting signal is estimated to be 3 standard deviations compared to the null hypothesis.
Article
Astronomy & Astrophysics
Nelson R. F. Braga, Octavio C. Junqueira
Summary: This study investigates the influence of rotation on the transition temperature of strongly interacting matter produced in non-central heavy ion collisions. By using a holographic description of an AdS black hole, the authors extend the analysis to the more realistic case where the matter spreads over a region around the rotational axis. The results show the coexistence of confined and deconfined phases and are consistent with the concept of local temperature in rotating frames developed by Tolman and Ehrenfest.
Article
Astronomy & Astrophysics
Bing Sun, Jiachen An, Zhoujian Cao
Summary: This paper investigates the effect of gravitational constant variation on the propagation of gravitational waves. By employing two analytical methods, the study finds that variations in the gravitational constant result in amplitude and phase corrections for gravitational waves, and the time variation of the gravitational constant can be constrained through the propagation of gravitational waves.
Article
Astronomy & Astrophysics
Abdellah Touati, Zaim Slimane
Summary: This letter presents the first study of Hawking radiation as a tunneling process within the framework of non-commutative gauge theory of gravity. The non-commutative Schwarzschild black hole is reconstructed using the Seiberg-Witten map and the star product. The emission spectrum of outgoing massless particles is computed using the quantum tunneling mechanism. The results reveal pure thermal radiation in the low-frequency scenario, but a deviation from pure thermal radiation in the high-frequency scenario due to energy conservation. It is also found that noncommutativity enhances the correlations between successively emitted particles.
Article
Astronomy & Astrophysics
Shahar Hod
Summary: The travel times of light signals between two antipodal points on a compact star's surface are calculated for two different trajectories. It is shown that, for highly dense stars, the longer trajectory along the surface may have a shorter travel time as measured by asymptotic observers. A critical value of the dimensionless density-area parameter is determined for constant density stars to distinguish cases where crossing through the star's center or following a semi-circular trajectory on the surface has a shorter travel time as measured by asymptotic observers.
