scholarly journals UA(1) SYMMETRY BREAKING AND THE SCALAR SECTOR OF QCD

2001 ◽  
Vol 16 (17) ◽  
pp. 3011-3024 ◽  
Author(s):  
M. NAPSUCIALE ◽  
S. RODRIGUEZ
Keyword(s):  
Symmetry Breaking ◽  
Chiral Symmetry ◽  
Vacuum Expectation ◽  
Spontaneous Breaking ◽  
Expectation Values ◽  
Qualitative And Quantitative ◽  
Quantitative Level ◽  
Pseudoscalar Mesons ◽  
Scalar Sector

It is shown that most of the unusual properties of the lowest lying scalar (and pseudoscalar) mesons can be understood, at the qualitative and quantitative level, on the basis of the breakdown of the UA(1) symmetry coupled to the vacuum expectation values of scalars by the spontaneous breaking of chiral symmetry.

Gauge hierarchies for chiral SU(N) × SU(N) groups

1976 ◽  
Vol 54 (16) ◽  
pp. 1660-1663 ◽  
Author(s):  
Shalom Eliezer
Keyword(s):  
Symmetry Breaking ◽  
Spontaneous Symmetry Breaking ◽  
Gauge Theories ◽  
Vacuum Expectation ◽  
Coupling Constants ◽  
Spontaneous Breaking ◽  
Text Representation ◽  
Algebraic Equations ◽  
Expectation Values ◽  
Special Case

We have presented a special case where a hierarchy of spontaneous breaking of the symmetries can be achieved in conventional gauge theories (i.e. the Higgs scalars are elementary bosons and the coupling constants of the quartic interactions are small). We break spontaneously the chiral group SU(N) × SU(N) with Higgs scalars transforming like the (N, [Formula: see text]) representation of SU(N) × SU(N). By minimizing the potential we obtain a set of algebraic equations of the type[Formula: see text]where ηj are the vacuum expectation values of the Higgs scalars and μi2 and Aij are parameters. In order to get a hierarchy of spontaneous symmetry breaking we obtain the condition det Aij = 0.

Chiral Symmetry

2019 ◽  
pp. 217-230
Author(s):  
Michael E. Peskin
Keyword(s):  
Symmetry Breaking ◽  
Spontaneous Symmetry Breaking ◽  
Chiral Symmetry ◽  
Goldstone Boson ◽  
Spontaneous Breaking ◽  
Quark Masses ◽  
Zero Mass ◽  
K Mesons ◽  
The Masses

This chapter introduces chiral symmetry, the extra symmetry that QCD acquires when the masses of quarks are set to zero. It introduces the concept of spontaneous symmetry breaking and explains the spontaneous breaking of chiral symmetry in QCD. It introduces the concept of a Goldstone boson, a particle that has zero mass as the result of spontaneous symmetry breaking, and explains how this concept explains properties of the pi and K mesons and allows us to determine the underlying values of the quark masses.

scholarly journals Right–right–left extension of the Standard Model

2016 ◽  
Vol 31 (19) ◽  
pp. 1650117 ◽  
Author(s):  
Gauhar Abbas
Keyword(s):  
Standard Model ◽  
Gauge Group ◽  
Vacuum Expectation ◽  
Expectation Values ◽  
Unique Pattern ◽  
Gauge Sector ◽  
Gauge Symmetries ◽  
The Standard Model ◽  
Higgs Fields ◽  
Scalar Sector

A right–right–left extension of the Standard Model is proposed. In this model, SM gauge group [Formula: see text] is extended to [Formula: see text]. The gauge symmetries [Formula: see text], [Formula: see text] are the mirror counterparts of the [Formula: see text] and [Formula: see text], respectively. Parity is spontaneously broken when the scalar Higgs fields acquire vacuum expectation values (VEVs) in a certain pattern. Parity is restored at the scale of [Formula: see text]. The gauge sector has a unique pattern. The scalar sector of the model is optimum, elegant and unique.

Chiral Symmetry Breaking and Pattern Formation in Two-Dimensional Films

1992 ◽  
Vol 292 ◽  
Author(s):  
Jonathan V. Selinger ◽  
Zhen-Gang Wang ◽  
Robijn F. Bruinsma
Keyword(s):  
Symmetry Breaking ◽  
Chiral Symmetry ◽  
Landau Theory ◽  
Chiral Symmetry Breaking ◽  
Orientational Order ◽  
Langmuir Monolayers ◽  
Spontaneous Breaking ◽  
Racemic Mixture ◽  
Two Dimensional ◽  
Freely Suspended

AbstractThin films of organic molecules, such as Langmuir monolayers and freely suspended smectic films, can exhibit a spontaneous breaking of chiral symmetry. This chiral symmetry breaking can occur through at least three possible mechanisms: (1) the relation between tilt order and bond-orientational order in a tilted hexatic phase, (2) a special packing of non-chiral molecules on a two-dimensional surface, and (3) phase separation of a racemic mixture. Because the chiral order parameter is coupled to variations in the direction of molecular tilt, chiral symmetry breaking leads to the formation of patterns in the tilt direction with one-dimensional or two-dimensional order. Using a Landau theory, we investigate these patterns and predict the critical behavior near the chiral symmetry breaking transition.

scholarly journals Temperature Dependence of the Axion Mass in a Scenario Where the Restoration of Chiral Symmetry Drives the Restoration of the UA(1) Symmetry

Universe ◽  
2019 ◽  
Vol 5 (10) ◽  
pp. 208 ◽  
Author(s):  
Davor Horvatić ◽  
Dalibor Kekez ◽  
Dubravko Klabučar
Keyword(s):  
Symmetry Breaking ◽  
Temperature Dependence ◽  
Chiral Symmetry ◽  
Quark Mass ◽  
Spontaneous Breaking ◽  
Axion Mass ◽  
Nonperturbative Qcd ◽  
Dynamical Breaking ◽  
Good Agreement

The temperature (T) dependence of the axion mass is predicted for T ′ s up to ∼ 2 . 3 × the chiral restoration temperature of QCD. The axion is related to the U A ( 1 ) anomaly. The squared axion mass m a ( T ) 2 is, modulo the presently undetermined scale of spontaneous breaking of Peccei–Quinn symmetry f a (squared), equal to QCD topological susceptibility χ ( T ) for all T. We obtain χ ( T ) by using quark condensates calculated in two effective Dyson–Schwinger models of nonperturbative QCD. They exhibit the correct chiral behavior, including the dynamical breaking of chiral symmetry and its restoration at high T. This is reflected in the U A ( 1 ) symmetry breaking and restoration through χ ( T ) . In our previous studies, such χ ( T ) yields the T-dependence of the U A ( 1 ) -anomaly-influenced masses of η ′ and η mesons consistent with experiment. This in turn supports our prediction for the T-dependence of the axion mass. Another support is a rather good agreement with the pertinent lattice results. This agreement is not spoiled by our varying u and d quark mass parameters out of the isospin limit.

scholarly journals A SIMPLE TOY MODEL FOR EFFECTIVE RESTORATION OF CHIRAL SYMMETRY IN EXCITED HADRONS

2006 ◽  
Vol 21 (25) ◽  
pp. 1939-1945 ◽  
Author(s):  
THOMAS D. COHEN ◽  
LEONID YA. GLOZMAN
Keyword(s):  
Symmetry Breaking ◽  
Chiral Symmetry ◽  
Chiral Symmetry Breaking ◽  
Salient Feature ◽  
Spontaneous Breaking ◽  
Small Correction

A simple solvable toy model exhibiting effective restoration of chiral symmetry in excited hadrons is constructed. A salient feature is that while physics of the low-lying states is crucially determined by the spontaneous breaking of chiral symmetry, in the high-lying states the effects of chiral symmetry breaking represent only a small correction. Asymptotically the states approach the regime where their properties are determined by the underlying unbroken chiral symmetry.

scholarly journals The EconomicalSU(3)C⊗SU(3)L⊗U(1)XModel

2008 ◽  
Vol 2008 ◽  
pp. 1-74 ◽  
Author(s):  
P. V. Dong ◽  
H. N. Long
Keyword(s):  
Gauge Boson ◽  
Vacuum Expectation ◽  
Mass Splitting ◽  
Lepton Number ◽  
Expectation Values ◽  
Gauge Bosons ◽  
Neutral Gauge Boson ◽  
Goldstone Bosons ◽  
The Standard Model ◽  
Scalar Sector

TheSU(3)C⊗SU(3)L⊗U(1)Xgauge model with minimal scalar sector, two Higgs triplets, is presented in detail. One of the vacuum expectation valuesuis a source of lepton-number violations and a reason for mixing among charged gauge bosons—the standard modelW±and the bilepton gauge bosonsY±, as well as among the neutral non-Hermitian bileptonX0and neutral gauge bosons—theZand the newZ′. An exact diagonalization of the neutral gauge boson sector is derived, and bilepton mass splitting is also given. Because of these mixings, the lepton-number violating interactions exist in both charged and neutral gauge boson sectors. Constraints on vacuum expectation values of the model are estimated andu≃𝒪(1)GeV,v≃vweak=246GeV, andω≃𝒪(1)TeV. In this model, there are three physical scalars, two neutral and one charged, and eight Goldstone bosons—the needed number for massive gauge bosons. The minimal scalar sector can provide all fermions including quarks and neutrinos consistent masses in which some of them require one-loop radiative corrections.

scholarly journals STRANGENESS AND CHIRAL SYMMETRY BREAKING

2011 ◽  
Vol 26 (04) ◽  
pp. 279-288 ◽  
Author(s):  
HARLEEN DAHIYA ◽  
NEETIKA SHARMA
Keyword(s):  
Symmetry Breaking ◽  
Chiral Symmetry ◽  
Significant Contribution ◽  
Constituent Quark ◽  
Chiral Symmetry Breaking ◽  
Quantitative Description ◽  
Constituent Quark Model ◽  
Matrix Elements ◽  
Qualitative And Quantitative

The implications of chiral symmetry breaking and SU(3) symmetry breaking have been studied in the chiral constituent quark model (χCQM). The role of hidden strangeness component has been investigated for the scalar matrix elements of the nucleon with an emphasis on the meson–nucleon sigma terms. The χCQM is able to give a qualitative and quantitative description of the "quark sea" generation through chiral symmetry breaking. The significant contribution of the strangeness is consistent with the recent available experimental observations.

Sign in / Sign up

Export Citation Format

Share Document