Isoscalar mesons upon unbreaking of chiral symmetry

Denissenya, Mikhail; Glozman, L. Ya.; Lang, C. B.

doi:10.1103/physrevd.91.034505

Cited by 58 publications

(126 citation statements)

References 31 publications

Supporting

Mentioning

118

Contrasting

Order By: Relevance

“…However, it does not appear to explain the full pattern. In particular, one of the J=1 correlation functions (an SU(4) singlet channel) was observed to be nearly identical to others (in an SU(4) 15-plet) [2] even though this is "accidental" from the perspective of SU(4) [7]. In this paper a natural solution to this puzzle is explored: namely that the emergent symmetry group is larger than SU (4) (and contains SU(4) as a subgroup).…”

Section: Introductionmentioning

confidence: 94%

“…one in which correlation functions of sources connected to each other by chiral transformations are identical. Moreover, for most channels a plateau in the effective mass plot continues to exist after the removal of these modes [1][2][3][4][5][6] which may be interpreted as suggesting that reasonably well defined hadronic resonances survive the truncation. However, what was found when the correlation functions were calculated was totally unexpected: a set of identical correlation functions that was much larger than could be explained by chiral symmetry alone.…”

Section: Introductionmentioning

confidence: 99%

“…It was not introduced lightly [1,2,[4][5][6]. Rather, it was suggested to explain a totally unexpected phenomenon recently observed in lattice calculations of correlation functions with various sources including those with the quantum numbers of spin zero, spin one and spin two mesons and of baryons.…”

Section: Introductionmentioning

confidence: 99%

“…To begin let us review the lattice calculations and how they have been interpreted previously [1][2][3][4][5][6][7]. The calculations in question are of correlation functions for gaugeinvariant local sources associated with various quantum numbers.…”

Section: Introductionmentioning

confidence: 99%

“…Recent lattice gauge calculations [1][2][3][4][5][6][7] may have shed significant light on this relationship. These calculations are quite remarkable in that they suggest that in a regime where effects of chiral dynamics are turned off by hand (and thus confinement dynamics may be expected to dominate) a new symmetry emerges which is larger than any explicitly in the QCD lagrangian [1,2,[4][5][6][7]. The nature of this putative emergent symmetry is the subject of the present paper.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

On the nature of an emergent symmetry in QCD with low-lying Dirac modes removed

Cohen

2016

Phys. Rev. D

View full text Add to dashboard Cite

Remarkable symmetry properties appear to arise in lattice calculations of correlation functions in which the lowest-lying eigenmodes of the Dirac operator in quark propagators are removed by hand. The Banks-Casher relation ties the chiral condensate to the density of low lying modes; thus, it is plausible that removal of such modes could lead to a regime where spontaneous chiral symmetry breaking does not occur. Surprising, a pattern of identical correlation functions was observed that is larger than can be explained by a restoration of chiral symmetry. This suggests that a larger symmetry-one that is not present in the QCD lagrangian-emerges when these modes are removed. Previously it was argued that this emergent symmetry was SU(4). However, when the low-lying modes are removed, the correlation functions of sources in the SU(4) 15-plet of spin-1 mesons appear to coincide with the correlation function of the SU(4) singlet. A natural explanation for this is an emergent symmetry larger than SU(4). In this work, it is shown that there exists no continuous symmetry whose generators in the field theory are spatial integrals of local operators that can account for the full pattern of identical correlation functions unless the apparent coincidence of the singlet channel with the 15-plet is accidental.

show abstract

Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

On the nature of an emergent symmetry in QCD with low-lying Dirac modes removed

Cohen

2016

Phys. Rev. D

View full text Add to dashboard Cite

show abstract

Parity doubling as a tool for right-handed current searches

Gratrex

Zwicky

2018

J. High Energ. Phys.

View full text Add to dashboard Cite

The V-A structure of the weak interactions leads to definite amplitude hierarchies in exclusive heavy-to-light decays mediated by b → (d, s)γ and b → (d, s) ¯ . However, the extraction of right-handed currents beyond the Standard Model is contaminated by V-A long-distance contributions leaking into right-handed amplitudes. We propose that these quantum-number changing long-distance contributions can be controlled by considering the almost parity-degenerate vector meson final states by exploiting the opposite relative sign of left-versus right-handed amplitudes. For example, measuring the time-dependent rates of a pair of vector V (J P = 1 − ) and axial A(1 + ) mesons in B → (V, A)γ, up to an order of magnitude is gained on the theory uncertainty prediction, controlled by long-distance ratios to the righthanded amplitude. This renders these decays clean probes to null tests, from the theory side. referred to as short-distance (SD) contributions hereafter, obey exact algebraic relations, leading to accidental control in the SD part. However, sizeable tree-level four-quark operators with charm and up quarks, H eff ∼d L γ µ UŪ L γ µ b (U = u, c), induce genuine long-distance (LD) effects, which are more difficult to control. It was argued, based on studying the inclusivē B → X s γ decay, that such contaminations could be rather significant [12], whereas actual computations show smaller effects in exclusive channels [13][14][15][16][17].In this article, we show that these LD effects can be controlled by a symmetry that in turn also explains the smallness found in the concrete computation [13] quoted just above. The symmetry in question is the chiral restoration limit. The crucial point is that decays of opposite parity, such asB → ρ(1 −− )γ versusB → a 1 (1 ++ )γ, are opposite in sign in the righthanded amplitude between the exact SD and LD contributions (originating from the sizeable V-A part). 1 While decays of axial mesons have received some attention as complementary probes for RHC (e.g. [21-23]), we advocate that the combination of the two decay channels allows for a cleaner extraction of the relevant observables controlled by ratios of vector to axial LD amplitudes. In light-cone approaches, this necessitates axial vector meson distribution amplitudes (DAs) [24], whose symmetry relations with vector meson DAs can be studied rather systematically [25]. For a simplified discussion of the main ideas of this paper we refer the reader to [26].The paper is organised as follows. In section 2 it is shown, using the path integral, that the fraction of LD-over SD-RHC flips sign for parity doublers. In section 3, the parity doublers are listed (section 3.1), followed by a discussion of the sources of correction to the symmetry limit in section 3.2. Applications to the time-dependent rates ofB → (V, A)γ, a detailed breakdown ofB s → φ(f 1 )γ, and remarks on B → (V, A) ¯ are presented in sections 4.1, 4.2 and 4.3 respectively. The paper ends with conclusions in section 5, including comments on the experimental feasibility of...

show abstract

Classical interactions of the instanton-dyons with antidyons

Larsen

Shuryak

2016

Nuclear Physics A

View full text Add to dashboard Cite

Instanton-dyons, also known as instanton-monopoles or instanton-quarks, are topological constituents of the instantons at nonzero temperature and nonzero expectation value of $A_4$. While the interaction between instanton-dyons has been calculated to one-loop order by a number of authors, that for dyon-antidyon pairs remains unknown even at the classical level. In this work we are filling this gap, by solving the gradient flow equation on a 3d lattice. We start with two well separated objects. We find that, after initial rapid relaxation, the configurations follow "streamline" set of configurations, which is basically independent on the initial configurations used. In striking difference to instanton-antiinstanton streamlines, in this case it ends at a quasi-stationary configuration, with an abrupt drop to perturbative fields. We parameterize the action of the streamline configurations, which is to be used in future many-body calculations.Comment: 10 pages, 12 figure

show abstract

Isoscalar mesons upon unbreaking of chiral symmetry

Cited by 58 publications

References 31 publications

On the nature of an emergent symmetry in QCD with low-lying Dirac modes removed

On the nature of an emergent symmetry in QCD with low-lying Dirac modes removed

Parity doubling as a tool for right-handed current searches

Classical interactions of the instanton-dyons with antidyons

Contact Info

Product

Resources

About