Flavor-singlet axial charge of the nucleon and anomalous Ward identity

1992 ◽  
Vol 281 (1-2) ◽  
pp. 141-147 ◽  
Author(s):  
Keh-Fei Liu
Keyword(s):  
Ward Identity ◽  
Axial Charge ◽  
Anomalous Ward Identity

scholarly journals Baryons and chiral symmetry

2017 ◽  
Vol 26 (01n02) ◽  
pp. 1740016 ◽  
Author(s):  
Keh-Fei Liu
Keyword(s):  
Chiral Symmetry ◽  
Ward Identity ◽  
Effective Theory ◽  
Roper Resonance ◽  
Lattice Calculation ◽  
The Third ◽  
Quark Spin ◽  
Quark Orbital Angular Momentum ◽  
Anomalous Ward Identity

The relevance of chiral symmetry in baryons is highlighted in three examples in the nucleon spectroscopy and structure. The first one is the importance of chiral dynamics in understanding the Roper resonance. The second one is the role of chiral symmetry in the lattice calculation of [Formula: see text] term and strangeness. The third one is the role of chiral [Formula: see text] anomaly in the anomalous Ward identity in evaluating the quark spin and the quark orbital angular momentum. Finally, the chiral effective theory for baryons is discussed.

scholarly journals Strange and charm quark spins from the anomalous Ward identity

2017 ◽  
Vol 95 (11) ◽  
Author(s):  
Ming Gong ◽  
Yi-Bo Yang ◽  
Jian Liang ◽  
Andrei Alexandru ◽  
Terrence Draper ◽  
...  
Keyword(s):  
Ward Identity ◽  
Charm Quark ◽  
Anomalous Ward Identity

scholarly journals Superfluids as higher-form anomalies

2020 ◽  
Vol 8 (3) ◽  
Author(s):  
Luca Delacrétaz ◽  
Diego Hofman ◽  
Grégoire Mathys
Keyword(s):  
Phase Transitions ◽  
Ward Identity ◽  
Goldstone Boson ◽  
Hydrodynamic Theory ◽  
Hydrodynamic Equations ◽  
Starting Point ◽  
Alternative Characterization ◽  
Superfluid Hydrodynamics ◽  
Anomalous Ward Identity

We recast superfluid hydrodynamics as the hydrodynamic theory of a system with an emergent anomalous higher-form symmetry. The higher-form charge counts the winding planes of the superfluid - its constitutive relation replaces the Josephson relation of conventional superfluid hydrodynamics. This formulation puts all hydrodynamic equations on equal footing. The anomalous Ward identity can be used as an alternative starting point to prove the existence of a Goldstone boson, without reference to spontaneous symmetry breaking. This provides an alternative characterization of Landau phase transitions in terms of higher-form symmetries and their anomalies instead of how the symmetries are realized. This treatment is more general and, in particular, includes the case of BKT transitions. As an application of this formalism we construct the hydrodynamic theories of conventional (0-form) and 1-form superfluids.

scholarly journals Quark spins and anomalous Ward identity

2018 ◽  
Vol 98 (7) ◽  
Author(s):  
Jian Liang ◽  
Yi-Bo Yang ◽  
Terrence Draper ◽  
Ming Gong ◽  
Keh-Fei Liu ◽  
...  
Keyword(s):  
Ward Identity ◽  
Anomalous Ward Identity

scholarly journals COMMENTS ON THE VACUUM ORIENTATIONS IN QCD

1992 ◽  
Vol 07 (33) ◽  
pp. 3147-3154 ◽  
Author(s):  
ZHENG HUANG ◽  
K.S. VISWANATHAN ◽  
DAN-DI WU
Keyword(s):  
Symmetry Breaking ◽  
Chiral Symmetry ◽  
Ward Identity ◽  
Chiral Symmetry Breaking ◽  
Dynamical Chiral Symmetry Breaking ◽  
Qcd Vacuum ◽  
Quark Field ◽  
Definition Of ◽  
Anomalous Ward Identity ◽  
Vacuum Alignment

We study the QCD vacuum orientation angles in correlation with the strong CP phases. A vacuum alignment equation of the dynamical chiral symmetry breaking is derived based on the anomalous Ward identity. It is emphasized that a chiral rotation of the quark field causes a change of the vacuum orientation and a change in the definition of the light pseudoscalar generators. As an illustration of the idea, η→2π decays are carefully studied in different chiral frames.

scholarly journals Quark and Glue Components of the Proton Spin from Lattice Calculation

2016 ◽  
Vol 40 ◽  
pp. 1660005 ◽  
Author(s):  
Keh-Fei Liu
Keyword(s):  
Angular Momentum ◽  
Orbital Angular Momentum ◽  
Ward Identity ◽  
Proton Spin ◽  
Lattice Calculation ◽  
Quark Spin ◽  
The Status ◽  
Quark Orbital Angular Momentum ◽  
Spin Crisis ◽  
Anomalous Ward Identity

The status of lattice calculations of the quark spin, the quark orbital angular momentum, the glue angular momentum and glue spin in the nucleon is summarized. The quark spin calculation is recently carried out from the anomalous Ward identity with chiral fermions and is found to be small mainly due to the large negative anomaly term which is believed to be the source of the ‘proton spin crisis’. We also present the first calculation of the glue spin at finite nucleon momenta.

scholarly journals Covariant phase space and soft factorization in non-Abelian gauge theories

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Temple He ◽  
Prahar Mitra
Keyword(s):  
Phase Space ◽  
Ward Identity ◽  
Gauge Theories ◽  
Minkowski Spacetime ◽  
Soft Gluon ◽  
Careful Study ◽  
Abelian Gauge ◽  
Gauge Sector ◽  
Vacuum States ◽  
The One

Abstract We perform a careful study of the infrared sector of massless non-abelian gauge theories in four-dimensional Minkowski spacetime using the covariant phase space formalism, taking into account the boundary contributions arising from the gauge sector of the theory. Upon quantization, we show that the boundary contributions lead to an infinite degeneracy of the vacua. The Hilbert space of the vacuum sector is not only shown to be remarkably simple, but also universal. We derive a Ward identity that relates the n-point amplitude between two generic in- and out-vacuum states to the one computed in standard QFT. In addition, we demonstrate that the familiar single soft gluon theorem and multiple consecutive soft gluon theorem are consequences of the Ward identity.

scholarly journals Infinite-dimensional fermionic symmetry in supersymmetric gauge theories

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Thomas T. Dumitrescu ◽  
Temple He ◽  
Prahar Mitra ◽  
Andrew Strominger
Keyword(s):  
Ward Identity ◽  
Gauge Theories ◽  
Soft Photon ◽  
Supersymmetric Gauge Theories ◽  
Null Infinity ◽  
Infinite Dimensional ◽  
Charged Matter ◽  
Gauge Symmetries ◽  
Supersymmetric Gauge

Abstract We establish the existence of an infinite-dimensional fermionic symmetry in four-dimensional supersymmetric gauge theories by analyzing semiclassical photino dynamics in abelian $$ \mathcal{N} $$ N = 1 theories with charged matter. The symmetry is parametrized by a spinor-valued function on an asymptotic S2 at null infinity. It is not manifest at the level of the Lagrangian, but acts non-trivially on physical states, and its Ward identity is the soft photino theorem. The infinite-dimensional fermionic symmetry resides in the same $$ \mathcal{N} $$ N = 1 supermultiplet as the physically non-trivial large gauge symmetries associated with the soft photon theorem.

scholarly journals Celestial superamplitude in $$ \mathcal{N} $$ = 4 SYM theory

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Hongliang Jiang
Keyword(s):  
Field Theory ◽  
Conformal Field Theory ◽  
Scattering Amplitudes ◽  
Momentum Space ◽  
Ward Identity ◽  
Yang Mills ◽  
Conformal Field ◽  
New Perspective ◽  
Celestial Sphere

Abstract Celestial amplitude is a new reformulation of momentum space scattering amplitudes and offers a promising way for flat holography. In this paper, we study the celestial amplitudes in $$ \mathcal{N} $$ N = 4 Super-Yang-Mills (SYM) theory aiming at understanding the role of superconformal symmetry in celestial holography. We first construct the superconformal generators acting on the celestial superfield which assembles all the on-shell fields in the multiplet together in terms of celestial variables and Grassmann parameters. These generators satisfy the superconformal algebra of $$ \mathcal{N} $$ N = 4 SYM theory. We also compute the three-point and four-point celestial super-amplitudes explicitly. They can be identified as the conformal correlation functions of the celestial superfields living at the celestial sphere. We further study the soft and collinear limits which give rise to the super-Ward identity and super-OPE on the celestial sphere, respectively. Our results initiate a new perspective of understanding the well-studied $$ \mathcal{N} $$ N = 4 SYM amplitudes via 2D celestial conformal field theory.

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