Journal articles: 'Four-quark condensates'

1

Eletsky, V. L. "Four-quark condensates at T≠0." Physics Letters B 299, no. 1-2 (January 1993): 111–14. http://dx.doi.org/10.1016/0370-2693(93)90890-t.

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2

Hong-Shi, Zong, and Sun Wei-Min. "Modified Approach for Calculating Four-Quark Condensates." Communications in Theoretical Physics 47, no. 2 (February 2007): 293–98. http://dx.doi.org/10.1088/0253-6102/47/2/021.

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3

Thomas, R., T. Hilger, and B. Kämpfer. "Four-quark condensates in nucleon QCD sum rules." Nuclear Physics A 795, no. 1-4 (November 2007): 19–46. http://dx.doi.org/10.1016/j.nuclphysa.2007.08.012.

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4

MOFFAT, J. W. "FINITE ELECTROWEAK THEORY WITHOUT A HIGGS PARTICLE." Modern Physics Letters A 06, no. 11 (April 10, 1991): 1011–21. http://dx.doi.org/10.1142/s0217732391001068.

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A unified electroweak theory is formulated using non-local field theory without including a Higgs particle. The W and Z gauge boson masses are induced from one-loop vacuum polarization graphs and the non-local weak scale is determined by the W boson mass and the Fermi constant to be Λw=424 GeV . The tree graphs for the gauge bosons are identical to those of the standard local electroweak theory, so any violation of locality occurs only at the quantum level for the finite loop graphs. The fermion masses are obtained from a four-Fermi interaction with a spontaneously broken vacuum based on the fermion condensate [Formula: see text]. The problem of severe fine tuning for the quark condensates in the standard local point field theory is avoided in our non-local field theory. The theory contains only the known particle spectrum of leptons, quarks, the anticipated top quark, the W and Z gauge bosons and the photon. The quark condensates could generate a spectrum of heavy vector bound states at an energy scale ~1−2 TeV .

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5

Thomas, R., T. Hilger, and B. Kämpfer. "Role of four-quark condensates in QCD sum rules." Progress in Particle and Nuclear Physics 61, no. 1 (July 2008): 297–303. http://dx.doi.org/10.1016/j.ppnp.2007.12.028.

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6

Hilger, T., T. Buchheim, B. Kämpfer, and S. Leupold. "Four-quark condensates in open-charm chiral QCD sum rules." Progress in Particle and Nuclear Physics 67, no. 2 (April 2012): 188–93. http://dx.doi.org/10.1016/j.ppnp.2011.12.016.

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7

Leupold, Stefan. "Factorization and non-factorization of in-medium four-quark condensates." Physics Letters B 616, no. 3-4 (June 2005): 203–7. http://dx.doi.org/10.1016/j.physletb.2005.04.046.

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8

Kartvelishvili, V. G., and M. V. Margvelashvili. "Pion parameters and four quark condensates from τ-decay data." Zeitschrift für Physik C Particles and Fields 55, no. 1 (March 1992): 83–88. http://dx.doi.org/10.1007/bf01558291.

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9

Khunjua, T. G., V. C. Zhukovsky, K. G. Klimenko, and R. N. Zhokhov. "Duality and Charged Pion Condensation in Chirally Asymmetric Dense Quark Matter in the Framework of an NJL2 Model." International Journal of Modern Physics: Conference Series 47 (January 2018): 1860093. http://dx.doi.org/10.1142/s2010194518600935.

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In this talk we present investigation of the phase structure of a (1+1)-dimensional quark model with four-quark interaction and in the presence of baryon ([Formula: see text]), isospin ([Formula: see text]) and chiral isospin ([Formula: see text]) chemical potentials. Spatially homogeneous and inhomogeneous (chiral density wave (for chiral condensate) and single wave (for charged pion condensate)) condensates are considered. It is established that in the large-[Formula: see text] limit ([Formula: see text] is the number of colored quarks) there exists a duality correspondence between the chiral symmetry breaking phase and the charged pion condensation (PC) one. The primary conclusion of this investigation is the fact that chiral isospin chemical potential generates charged pion condensation with non-zero baryon density in dense quark matter. Moreover, it is shown that inhomogeneous charged PC phase with nonzero baryon density is induced in the model by arbitrary small values of the chemical potential [Formula: see text] (for a rather large region of [Formula: see text] and [Formula: see text]).

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10

Fariborz, Amir H., and Renata Jora. "Examining a possible cascade effect in chiral symmetry breaking." Modern Physics Letters A 32, no. 02 (December 29, 2016): 1750008. http://dx.doi.org/10.1142/s0217732317500080.

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We examine a toy model and a cascade effect for confinement and chiral symmetry breaking which consists in several phase transitions corresponding to the formation of bound states and chiral condensates with different number of fermions for a strong group. We analyze two examples: regular quantum chromodynamics (QCD) where we calculate the “four quark” vacuum condensate and a preon composite model based on QCD at higher scales. In this context, we also determine the number of flavors at which the second chiral and confinement phase transitions occur and discuss the consequences.

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11

BIAN, JIAN-GUO, and TAO HUANG. "PSEUDOSCALAR DECAY CONSTANTS AND MASS SPECTRUM OF $q\bar q$ AND $Q\bar q$ SYSTEM IN QCD THEORY INVOLVING THE VACUUM CONDENSATES." Modern Physics Letters A 08, no. 07 (March 7, 1993): 635–45. http://dx.doi.org/10.1142/s0217732393000660.

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We present the results of a study of light-light and heavy-light quark bound states by solving the Bethe-Salpeter equation, in which the non-perturbative part of the kernel is calculated up to four dimensions vacuum condensates in QCD in the background fields. We believe that it is a good approximation to neglect higher dimension vacuum condensates since we only deal with the ground states for 0− mesons. Indeed, satisfactory results (spectrum and decay constants) are obtained with reasonable parameters. In particular, we get an approximate relation [Formula: see text] for the heavy-light quark mesons numerically.

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12

AFONIN, S. S. "RELATION BETWEEN QUARK AND GLUON CONDENSATES FROM QCD SUM RULES." International Journal of Modern Physics A 21, no. 32 (December 30, 2006): 6693–98. http://dx.doi.org/10.1142/s0217751x0603494x.

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It is shown that QCD sum rules in the planar limit lead to a certain relation between four important quantities: ρ-meson mass, weak π-meson decay constant, quark and gluon condensates. As a byproduct an explanation for the dominance of ρρ-decay for the f0(1370)-meson is proposed.

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13

Leupold, Stefan. "Four-quark condensates and chiral symmetry restoration in a resonance gas model." Journal of Physics G: Nuclear and Particle Physics 32, no. 11 (September 18, 2006): 2199–217. http://dx.doi.org/10.1088/0954-3899/32/11/013.

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14

MATHEUS, R. D., and M. NIELSEN. "X(3872) AS TETRAQUARKS IN QCD SUM RULES." International Journal of Modern Physics E 16, no. 09 (October 2007): 2906–9. http://dx.doi.org/10.1142/s0218301307008690.

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QCD spectral sum rules is used to test the nature of the meson X(3872), assumed to be an exotic four-quark [Formula: see text] state with JPC = 1++. For definiteness, the current proposed recently by Maiani et al1 is used, at leading order in αs, considering the contributions of higher dimension condensates. The value MX = (3.94 ± 0.17) GeV is found which is compatible, within the errors, with the experimental candidate X(3872). The uncertainties of our estimates are mainly due to the one from the c quark mass.

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15

Christos, GA. "Alternative Scheme of Spontaneous Chiral Symmetry Breaking." Australian Journal of Physics 39, no. 3 (1986): 347. http://dx.doi.org/10.1071/ph860347.

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We develop an alternative scheme of spontaneous chiral symmetry breaking which is characterized by four-quark condensates instead of (7jq),*O. In this scheme the Nambu-Goldstone bosons acquire a mass squared - m~uark' in comparison with mquark in the usual scheme. The quark mass ratios and the parameters of the scheme are determined by an application to the pseudoscalar nonet spectrum (including 'lT0_'Yj_'Yj' mixing). The decays Iji -+('lT0 , 'Yj, 'Yj}y and Iji' -+ 1ji('lT0 , 'Yj) are also considered. The results do not promote the alternative scheme.

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16

Bhattacharya, A., R. Ghosh, and B. Chakrabarti. "Meson and diquark condensates in the NJL model and the Fermi momentum." International Journal of Modern Physics A 31, no. 28n29 (October 19, 2016): 1645043. http://dx.doi.org/10.1142/s0217751x16450433.

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Quark–anti quark and diquark condensation have been investigated in the framework of the NJL model. The Pauli–Villars regularization scheme have been used for the investigation of meson condensation in three dimension whereas the four dimensional case has been studied using the Schwinger–Dyson equation considering the Hartree approximation. Diquark condensation in three and four dimension have also been studied considering the Pauli–Villars regularization scheme. Using the Fermi momentum [Formula: see text] of the particle as cut-off parameter, the gap energy/coherence length for meson condensation [Formula: see text] have been investigated whereas for diquark [Formula: see text] the critical gap energy/critical coherence length (the distance over which there would be no diquark condensation) have been extracted. The variation of the coherence length/gap energy with [Formula: see text] have also been investigated. The results are compared with exciting data. Some interesting observations are made.

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17

Wang, Qing, Yu-Ping Kuang, Yu-Ping Yi, and Tian-Fang Cai. "Calculation of the four-quark condensates in the QCD motivated Nambu-Jona-Lasinio model." Physics Letters B 336, no. 1 (September 1994): 70–76. http://dx.doi.org/10.1016/0370-2693(94)00983-x.

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18

LAVELLE, MARTIN, and MICHAEL OLESZCZUK. "THE OPERATOR PRODUCT EXPANSION OF THE QCD PROPAGATORS." Modern Physics Letters A 07, no. 39 (December 21, 1992): 3617–30. http://dx.doi.org/10.1142/s0217732392003049.

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We bring together for the first time the coefficients in covariant gauges of all the condensates of dimension four or less in the operator product expansion (OPE) of the quark, gluon and ghost propagators. It is stressed that contrary to general belief the condensates do not enter the OPE of the propagators in gauge-invariant combinations like [Formula: see text] and 〈G2〉. The results are presented in arbitrary dimension to lowest order in the light quark masses for the SU (Nc) internal symmetry group. All terms which, through the equations of motion, may be viewed as being effectively of order αs are included. The importance of the equations of motion if one is to fulfill the Slavnov-Taylor identities is demonstrated. We briefly consider the equivalent, but less complete, calculations in other gauges and give an overview of the status of the OPE of the QCD vertices. Finally we discuss what these non-perturbative structures tell us about the correct solutions of QCD and point out their significance for the Fourier acceleration technique as applied to lattice QCD.

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19

Albuquerque, R., S. Narison, F. Fanomezana, A. Rabemananjara, D. Rabetiarivony, and G. Randriamanatrika. "XYZ-like spectra from Laplace sum rule at N2LO in the chiral limit." International Journal of Modern Physics A 31, no. 36 (December 28, 2016): 1650196. http://dx.doi.org/10.1142/s0217751x16501967.

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We present new compact integrated expressions of QCD spectral functions of heavy-light molecules and four-quark [Formula: see text]-like states at lowest order (LO) of perturbative (PT) QCD and up to [Formula: see text] condensates of the Operator Product Expansion (OPE). Then, by including up to next-to-next leading order (N2LO) PT QCD corrections, which we have estimated by assuming the factorization of the four-quark spectral functions, we improve previous LO results from QCD spectral sum rules (QSSR), on the [Formula: see text]-like masses and decay constants which suffer from the ill-defined heavy quark mass. PT N3LO corrections are estimated using a geometric growth of the PT series and are included in the systematic errors. Our optimal results based on stability criteria are summarized in Tables 11–14 and compared, in Sec. 10, with experimental candidates and some LO QSSR results. We conclude that the masses of the [Formula: see text] observed states are compatible with (almost) pure [Formula: see text], [Formula: see text] molecule or/and four-quark states. The ones of the [Formula: see text], [Formula: see text] molecule/four-quark states are about 1.5 GeV above the [Formula: see text] mesons experimental candidates and hadronic thresholds. We also find that the couplings of these exotics to the associated interpolating currents are weaker than that of ordinary [Formula: see text] mesons [Formula: see text] and may behave numerically as [Formula: see text] (respectively [Formula: see text]) for the [Formula: see text], [Formula: see text] (respectively [Formula: see text], [Formula: see text]) states which can stimulate further theoretical studies of these decay constants.

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20

Fariborz, Amir H., A. Pokraka, and T. G. Steele. "Connections between chiral Lagrangians and QCD sum-rules." Modern Physics Letters A 31, no. 03 (January 18, 2016): 1650023. http://dx.doi.org/10.1142/s0217732316500231.

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In this paper, it is shown how a chiral Lagrangian framework can be used to derive relationships connecting quark-level QCD correlation functions to mesonic-level two-point functions. Crucial ingredients of this connection are scale factor matrices relating each distinct quark-level substructure (e.g. quark–antiquark, four-quark) to its mesonic counterpart. The scale factors and mixing angles are combined into a projection matrix to obtain the physical (hadronic) projection of the QCD correlation function matrix. Such relationships provide a powerful bridge between chiral Lagrangians and QCD sum-rules that are particularly effective in studies of the substructure of light scalar mesons with multiple complicated resonance shapes and substantial underlying mixings. The validity of these connections is demonstrated for the example of the isotriplet [Formula: see text] system, resulting in an unambiguous determination of the scale factors from the combined inputs of QCD sum-rules and chiral Lagrangians. These scale factors lead to a remarkable agreement between the quark condensates in QCD and the mesonic vacuum expectation values that induce spontaneous chiral symmetry breaking in chiral Lagrangians. This concrete example shows a clear sensitivity to the underlying [Formula: see text]-system mixing angle, illustrating the value of this methodology in extensions to more complicated mesonic systems.

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21

Morimoto, Masatoshi, Yasuhiko Tsue, João da Providência, Constança Providência, and Masatoshi Yamamura. "Hybrid stars from a three-flavor NJL model with two kinds of tensor condensates." International Journal of Modern Physics E 29, no. 10 (October 2020): 2050093. http://dx.doi.org/10.1142/s0218301320500937.

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To obtain the equation of state of quark matter and construct hybrid stars, we calculate the thermodynamic potential in the three-flavor Nambu–Jona-Lasinio model including the tensor-type four-point interaction and the Kobayashi–Maskawa–’t Hooft interaction. To construct the hybrid stars, it is necessary to impose the [Formula: see text] equilibrium and charge neutrality conditions on the system. It is shown that tensor condensed phases appear at large chemical potential. Under the possibility of the existence of the tensor condensates, the relationship between the radius and mass of hybrid stars is estimated.

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22

Albuquerque, R., S. Narison, D. Rabetiarivony, and G. Randriamanatrika. "XYZ-SU3 breakings from Laplace sum rules at higher orders." International Journal of Modern Physics A 33, no. 16 (June 7, 2018): 1850082. http://dx.doi.org/10.1142/s0217751x18500823.

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We present new compact integrated expressions of SU3 breaking corrections to QCD spectral functions of heavy–light molecules and four-quark [Formula: see text]-like states at lowest order (LO) of perturbative (PT) QCD and up to [Formula: see text] condensates of the Operator Product Expansion (OPE). Including next-to-next-to-leading order (N2LO) PT corrections in the chiral limit and next-to-leading order (NLO) SU3 PT corrections, which we have estimated by assuming the factorization of the four-quark spectral functions, we improve previous LO results for the [Formula: see text]-like masses and decay constants from QCD spectral sum rules (QSSR). Systematic errors are estimated from a geometric growth of the higher order PT corrections and from some partially known [Formula: see text] nonperturbative contributions. Our optimal results, based on stability criteria, are summarized in Tables 18–21 while the [Formula: see text] and [Formula: see text] channels are compared with some existing LO results in Table 22. One can note that, in most channels, the SU3 corrections on the meson masses are tiny: [Formula: see text] (respectively [Formula: see text]) for the [Formula: see text] (respectively [Formula: see text])-quark channel but can be large for the couplings ([Formula: see text]). Within the lowest dimension currents, most of the [Formula: see text] and [Formula: see text] states are below the physical thresholds while our predictions cannot discriminate a molecule from a four-quark state. A comparison with the masses of some experimental candidates indicates that the [Formula: see text] [Formula: see text] might have a large [Formula: see text] molecule component while an interpretation of the [Formula: see text] candidates as four-quark ground states is not supported by our findings. The [Formula: see text] [Formula: see text] and [Formula: see text] are compatible with the [Formula: see text], [Formula: see text] molecules and/or with the axial-vector [Formula: see text] four-quark ground state. Our results for the [Formula: see text], [Formula: see text] and for different beauty states can be tested in the future data. Finally, we revisit our previous estimates1 for the [Formula: see text] and [Formula: see text] and present new results for the [Formula: see text].

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23

Celenza, L. S., C. M. Shakin, Wei-Dong Sun, and J. Szweda. "Use of the Nambu–Jona-Lasino model in the calculation of the density dependence of four-quark condensates." Physical Review C 51, no. 2 (February 1, 1995): 937–49. http://dx.doi.org/10.1103/physrevc.51.937.

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24

Bang-Rong, Zhou. "Quark-Antiquark and Diquark Condensates in Vacuum in Two-Flavor Four-Fermion Interaction Models with Any Color Number N c." Communications in Theoretical Physics 51, no. 4 (April 2009): 700–706. http://dx.doi.org/10.1088/0253-6102/51/4/23.

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25

Bang-Rong, Zhou. "Erratum: Quark–Antiquark and Diquark Condensates in Vacuum in Two-Flavor Four-Fermion Interaction Models with Any Color Number N c [Commun. Theor. Phys. 51 (2009) 700]." Communications in Theoretical Physics 54, no. 3 (September 2010): 499. http://dx.doi.org/10.1088/0253-6102/54/3/24.

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26

HongShi, Zong, Lü XiaoFu, Zhao EnGuang, and Wang Fan. "Nonlocal Four-Quark Condensate and Vacuum Susceptibilities." Communications in Theoretical Physics 33, no. 4 (June 15, 2000): 687–90. http://dx.doi.org/10.1088/0253-6102/33/4/687.

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27

ZONG, HONG-SHI, DENG-KE HE, FENG-YAO HOU, and WEI-MIN SUN. "GENERAL FORMULA FOR THE FOUR-QUARK CONDENSATE AND VACUUM FACTORIZATION ASSUMPTION." International Journal of Modern Physics A 23, no. 10 (April 20, 2008): 1507–20. http://dx.doi.org/10.1142/s0217751x08039700.

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By differentiating the dressed quark propagator with respect to a variable background field, the linear response of the dressed quark propagator in the presence of the background field can be obtained. From this general method, using the vector background field as an illustration, we derive a general formula for the four-quark condensate [Formula: see text]. This formula contains the corresponding fully dressed vector vertex and it is shown that factorization for [Formula: see text] holds only when the dressed vertex is taken to be the bare one. This property also holds for all other types of four-quark condensate. By comparing this formula with the general expression for the corresponding vacuum susceptibility, it is found that there exists some intrinsic relation between these two quantities, which are usually treated as independent phenomenological inputs in the QCD sum rule external field approach. The above results are also generalized to the case of finite chemical potential and the factorization problem of the four-quark condensate at finite chemical potential is discussed.

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28

PAVEL, H. P., D. BLASCHKE, G. RÖPKE, and V. N. PERVUSHIN. "SQUEEZED GLUON CONDENSATE AND QUARK CONFINEMENT IN THE GLOBAL COLOR MODEL OF QCD." International Journal of Modern Physics A 14, no. 02 (January 20, 1999): 205–24. http://dx.doi.org/10.1142/s0217751x99000105.

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We discuss how the presence of a squeezed gluon vacuum might lead to quark confinement in the framework of the global color model of QCD. Using reduced phase space quantization of massive vector theory we construct a Lorentz-invariant and colorless squeezed gluon condensate and show that it induces a permanent, nonlocal quark interaction (delta-function in four-momentum space), which according to Munczek and Nemirovsky might lead to quark confinement. Our approach makes it possible to relate the strength of this effective confining quark interaction to the strength of the physical gluon condensate.

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29

Morimoto, Masatoshi, Yasuhiko Tsue, João da Providência, Constança Providência, and Masatoshi Yamamura. "Spontaneous magnetization under a pseudovector interaction between quarks in high density quark matter." International Journal of Modern Physics E 27, no. 04 (April 2018): 1850028. http://dx.doi.org/10.1142/s0218301318500283.

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Spontaneous magnetization and magnetic susceptibility originated from the pseudovector-type four-point interaction between quarks are calculated in quark matter with zero temperature and finite quark chemical potential by using the two-flavor Nambu–Jona-Lasinio model. It is shown that both the chiral condensate and spin polarized condensate coexist in a narrow region of the quark chemical potential. And then, it is also shown that, in this narrow region, the spontaneous magnetization appears. Also, the magnetic susceptibility due to quarks with the positive energy is evaluated in the spin polarized phase.

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30

Bertlmann, R. A., C. A. Dominguez, M. Loewe, M. Perrottet, and E. Rafael. "Determination of the gluon condensate and the four quark condensate via FESR." Zeitschrift für Physik C Particles and Fields 39, no. 2 (June 1988): 231–40. http://dx.doi.org/10.1007/bf01550999.

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31

Fariborz, Amir H., Renata Jora, Salah Nasri, and Joseph Schechter. "A hierarchy of the quark masses in a top condensate model with multiple Higgses." Modern Physics Letters A 29, no. 06 (February 28, 2014): 1450030. http://dx.doi.org/10.1142/s0217732314500308.

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We discuss the quark masses in a top condensate model where not only two quark but also four quark composite states may exist. We show that the presence of the top color group SU (3)1× SU (3)2 with the correct quark representations can justify even in the absence of the additional technicolor interactions a hierarchy of the quark masses where the light quarks masses have the same size, the charm and bottom masses are higher and similar and the top is the heaviest.

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32

FARIBORZ, AMIR H., RENATA JORA, and JOSEPH SCHECHTER. "GENERALIZED SIGMA MODEL DESCRIPTION OF THE LIGHT J = 0 MESONS." International Journal of Modern Physics A 20, no. 27 (October 30, 2005): 6178–88. http://dx.doi.org/10.1142/s0217751x05029204.

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Within a linear sigma model framework, possible mixing between two chiral nonets (a two quark nonet, and a four quark nonet) below 2 GeV is studied. Incorporating the U (1)A behavior of the underlying QCD, and working in the isospin invariant limit, the mass spectra of the I = 0, I = 1/2 and I = 1 pseudoscalars, and the I = 1/2 scalars are studied, and estimates of their quark content are presented. It is found, as expected, that the ordinary and the excited pseudoscalars generally have much less two and four quark admixtures compared to the respective scalars. As by-products, several quantities such as the four quark vacuum condensate, and the decay constant of excited states are predicted.

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33

HongShi, Zong, Lü XiaoFu, Wang Fan, Chang ChaoHsi, and Zhao EnGuang. "Calculation of Four-Quark Condensate Beyond Vacuum Saturation Approximation." Communications in Theoretical Physics 34, no. 3 (October 30, 2000): 563–66. http://dx.doi.org/10.1088/0253-6102/34/3/563.

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34

CHEN, LI-AN, and LONG-QING HE. "VECTOR AND AXIAL-VECTOR CORRELATORS AND THE FOUR-QUARK CONDENSATE." Modern Physics Letters A 26, no. 25 (August 20, 2011): 1887–96. http://dx.doi.org/10.1142/s0217732311036036.

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In this paper we calculate the difference between vector and axial-vector correlators with two different vertices: the bare vertex and the Ball–Chiu vertex (BC vertex) ansatz. Through the difference we compare the results drawn from the chiral sum rules. The leading nonzero contribution of the difference of the correlators in the ultraviolet identifies the four-quark condensate, which is the leading nonperturbative phenomenon in QCD. Also the pion decay constant can be drawn. For the quark propagator, we employ two different models. One is calculated in the framework of the rainbow-ladder approximation scheme in the Dyson–Schwinger approach. The other is the analytic fit employed in Ref. 1. Results show that the dressing effects of the vector and axial-vector vertices are very important.

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35

IVANOV, A. N., N. I. TROITSKAYA, and M. NAGY. "THE PROBLEM OF BOSONIZATION OF LOCAL FOUR-QUARK OPERATORS." International Journal of Modern Physics A 08, no. 20 (August 10, 1993): 3425–55. http://dx.doi.org/10.1142/s0217751x93001375.

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The problem of bosonization of standard local four-quark operators, by involving the penguin operator, with ΔI = 1/2 and ΔS = 1 selection rules, is studied. We show that the well-known Cronin's operator determined within the effective chiral Lagrangian approach with nonlinear realization of chiral SU (3) × SU (3) symmetry (so-called chiral perturbation theory at the hadronic level) can realize the hadronic level description of local four-quark operators with (V − A) × (V − A) quark structure only. Also, it is shown that any attempts to apply Cronin's operator for bosonization of the penguin operator, possessing (V − A) × (V + A) quark structure, are doomed to failure. The latter is explained by the inability of Cronin's operator to describe correctly the s-wave final-state interaction, which is very important for transitions governed by the penguin operator. The asymmetry of quark condensate is calculated. The sign of this asymmetry is opposite to that one assumed in the framework of QCD sum rules.

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36

MIRANSKY, V. A., MASAHARU TANABASHI, and KOICHI YAMAWAKI. "IS THE t QUARK RESPONSIBLE FOR THE MASS OF W AND Z BOSONS?" Modern Physics Letters A 04, no. 11 (June 10, 1989): 1043–53. http://dx.doi.org/10.1142/s0217732389001210.

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Based on the dynamical model having a large anomalous dimension γm≃2, we propose that the t quark condensate is responsible for the mass of W and Z bosons within the framework of the SU (3)C×SU(2)L×U(1)Y gauge theory (without Higgs) plus four-fermion interactions among quarks and leptons. This accounts for the largeness of the t quark mass mt without violating the weak-isospin relation [Formula: see text]. Quark/lepton mass matrices are obtained through the four-fermion interactions, which yields no serious flavor-changing neutral currents. The model predicts a [Formula: see text] composite scalar meson with a mass ≃2mt. A possibility for an unusual resolution of the strong CP problem is also suggested.

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37

Friesen, A. V., Yu L. Kalinovsky, and V. D. Toneev. "Vector interaction effect on thermodynamics and phase structure of QCD matter." International Journal of Modern Physics A 30, no. 16 (June 9, 2015): 1550089. http://dx.doi.org/10.1142/s0217751x1550089x.

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The two-flavor Polyakov-loop extended model is generalized by taking into account the effective four-quark vector-type interaction with the coupling strengths, which are endowed with a dependence on the Polyakov field Φ. The effective vertex generates entanglement interaction between the Polyakov loop and the chiral condensate. We investigate the influence of an additional quark vector interaction and the entanglement interaction on thermodynamics of a quark system and in particular on the location of the critical end-point at the given chemical potential or quark density. It is shown that the finite value of the singlet vector interaction strength G v improves the model agreement with the lattice data. The influence of the nonzero G v and entanglement on the thermodynamic observables and the curvature of the crossover boundary in the T – μ plane is also examined.

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Govaerts, J., L. J. Reinders, F. De Viron, and J. Weyers. "L = 1 mesons and the four-quark condensate in QCD sum rules." Nuclear Physics B 283 (January 1987): 706–22. http://dx.doi.org/10.1016/0550-3213(87)90294-x.

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MARGVELASHVILI, M. "THE ELECTROMAGNETIC MASS DIFFERENCE OF PIONS FROM QCD." International Journal of Modern Physics A 05, no. 04 (February 20, 1990): 747–53. http://dx.doi.org/10.1142/s0217751x90000337.

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It is shown that the two point functions of definite class can be calculated, at small spacelike momenta, as subtraction constants in the Borel transformed QCD sum rules. Using the results of current algebra and PCAC, we obtain three different sum rules for determination of the electromagnetic mass difference of pions. The result is in a good agreement with experiment, and confirms the standard value for the four-quark vacuum condensate.

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MITRA, A. N. "STRONG SU(2) BREAKING AND MASS SPLITTINGS IN PSEUDOSCALAR MESONS." International Journal of Modern Physics A 11, no. 29 (November 20, 1996): 5245–59. http://dx.doi.org/10.1142/s0217751x96002406.

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The mass splittings within the SU(2) multiplets of pseudoscalar mesons (π, K, D, B) are used as a laboratory to determine the mass difference between d and u quarks (current), through the simplest (two-point) quark-loop diagrams for the self-energies of the corresponding hadrons, together with the associated quark-condensate diagrams within the loops. The second-order e.m. correction is also calculated with a photon line joining the two opposite quark lines in the self-energy loop. The basic ingredient is a hadron–quark-vertex function generated from a vector-exchange-like (chirally invariant) four-fermion Lagrangian (with current quarks) under dynamical symmetry breaking (DχSB), precalibrated to spectroscopy and other important low-energy amplitudes. The results which are expressed as proportional to the u−d mass difference δc, but are otherwise free from any adjustable parameters, reproduce in a rather accurate way all the SU(2) mass differences (from kaon to bottom) with δc = 4.0 MeV, when all the three self-energy diagrams are included. The pion receives only e.m. contributions with a value 5.24 MeV.

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XUE, SHE-SHENG. "FINE-TUNING THE LOW-ENERGY PHYSICS." Modern Physics Letters A 15, no. 17 (June 7, 2000): 1089–98. http://dx.doi.org/10.1142/s021773230000133x.

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In this letter we discuss the problem of the extreme fine-tuning necessary to achieve the quark mass scale mt within the dynamical symmetry breaking of the phenomenological [Formula: see text] condensate model. Inspired by the vector-like phenomenon of chiral gauge theories at short distances, we postulate that the W±-gauge bosons possess a vector-like gauge coupling and contribute to the gap-equations of quark self-energy functions in the high-energy region. We find that the gap-equations of different charge sectors are coupled, and as a result the unnatural fine-tuning is overcome and the ratio of the top and bottom masses is related to the electric charge: [Formula: see text], provided the quadratic divergence is removed by setting the four-fermion coupling [Formula: see text].

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Islam, M. M., and R. J. Luddy. "Condensate-enclosed chiral-bag model of the proton and pp elastic scattering at LHC 13 TeV." Modern Physics Letters A 30, no. 39 (December 7, 2015): 1550218. http://dx.doi.org/10.1142/s0217732315502181.

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Our investigation of high energy [Formula: see text] and [Formula: see text] elastic scattering over the last ten years has led us to consider that the proton has three regions: (i) an outer region consisting of a quark–antiquark [Formula: see text] condensate ground state (also described as quark–antiquark outer cloud), (ii) an inner shell of topological (geometrical) baryonic charge of size [Formula: see text] 0.44 fm, and (iii) a core of size [Formula: see text] 0.2 fm, where the three valence quarks of a proton with baryonic charges are confined. The proton structure that has emerged leads to four main elastic scattering processes in [Formula: see text] scattering. The first process (which gives rise to diffraction scattering) is described by a profile function. The second process involves multiple [Formula: see text]-exchanges. The third process in [Formula: see text] scattering is quark–quark scattering via gluon–gluon interaction. The fourth process — which appears for the first time in our investigation of [Formula: see text] scattering — is a glancing collision at the boundary of a proton with that of the other proton. To describe quantitatively the four processes, their parameters have to be determined. For this purpose, we investigate: (i) [Formula: see text] 7 TeV [Formula: see text] measured by the TOTEM Collaboration and (ii) [Formula: see text] 1.96 TeV [Formula: see text] measured by the D0 Collaboration. Once the parameters are satisfactorily obtained, we calculate [Formula: see text] [Formula: see text] at 7 TeV and compare with the TOTEM data. We also calculate [Formula: see text] [Formula: see text] at 1.96 TeV and compare with the D0 data. We then predict [Formula: see text] elastic [Formula: see text] at 13 TeV which will soon be measured at LHC by the TOTEM Collaboration. This measurement will establish how well we have predicted the 13 TeV [Formula: see text] and determined the structure of the proton.

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Tawfik, Abdel Nasser, and Niseem Magdy. "On SU(3) Effective Models and Chiral Phase Transition." Advances in High Energy Physics 2015 (2015): 1–15. http://dx.doi.org/10.1155/2015/563428.

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Sensitivity of Polyakov Nambu-Jona-Lasinio (PNJL) model and Polyakov linear sigma-model (PLSM) has been utilized in studying QCD phase-diagram. From quasi-particle model (QPM) a gluonic sector is integrated into LSM. The hadron resonance gas (HRG) model is used in calculating the thermal and dense dependence of quark-antiquark condensate. We review these four models with respect to their descriptions for the chiral phase transition. We analyze the chiral order parameter, normalized net-strange condensate, and chiral phase-diagram and compare the results with recent lattice calculations. We find that PLSM chiral boundary is located in upper band of the lattice QCD calculations and agree well with the freeze-out results deduced from various high-energy experiments and thermal models. Also, we find that the chiral temperature calculated from HRG is larger than that from PLSM. This is also larger than the freeze-out temperatures calculated in lattice QCD and deduced from experiments and thermal models. The corresponding temperature and chemical potential are very similar to that of PLSM. Although the results from PNJL and QLSM keep the same behavior, their chiral temperature is higher than that of PLSM and HRG. This might be interpreted due the very heavy quark masses implemented in both models.

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HACKEL, M., M. FABER, H. MARKUM, and M. MÜLLER. "CHIRAL INTERFACE FOR QCD WITH DYNAMICAL FERMIONS." International Journal of Modern Physics C 03, no. 05 (October 1992): 961–70. http://dx.doi.org/10.1142/s0129183192000622.

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The free energy distribution across the interface of coexisting quark and hadron mat-ter is studied in the framework of lattice QCD. We calculate the interface tension α with the “differential method” for pure SU(3) gauge theory and in the presence of dynamical quarks with four flavors. Using lattices with spatial volume 82×16 it turns out that α is very small and compatible with zero. The chiral condensate indicates the same width of the domain wall as the Polyakov loop distribution and the other thermodynamical observables.

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Zschocke, S., O. P. Pavlenko, and B. Kämpfer. "In-medium spectral change of ω mesons as a probe of QCD four-quark condensate." Physics Letters B 562, no. 1-2 (June 2003): 57–62. http://dx.doi.org/10.1016/s0370-2693(03)00551-3.

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ARBUZOV, BORIS A., and IVAN V. ZAITSEV. "NONPERTURBATIVE SOLUTIONS IN THE ELECTROWEAK THEORY WITH $\bar t t$ CONDENSATE AND THE t-QUARK MASS." International Journal of Modern Physics A 26, no. 29 (November 20, 2011): 4945–58. http://dx.doi.org/10.1142/s0217751x11054784.

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We apply Bogoliubov compensation principle to the gauge electroweak interaction. The nontrivial solution of compensation equations for anomalous three-boson gauge invariant effective interaction uniquely defines its form-factor and parameters of the theory including value of gauge electroweak coupling [Formula: see text] in satisfactory agreement with the experimental value. A possibility of spontaneous generation of effective four-fermion interaction of heavy quarks is demonstrated. This interaction defines an equation for a scalar bound state of heavy quarks which serve as a substitute for the elementary scalar Higgs doublet. As a result we calculate the t-quark mass mt = 177 GeV in satisfactory agreement with the experimental value. The results strongly support idea of [Formula: see text] condensate as a source of the electroweak symmetry breaking. The approach predicts heavy composite Higgs scalar MH ≃ 1800 GeV .

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Johnson, Mikkel B., and Leonard S. Kisslinger. "Light-quark mesons and four-quark condensates at finite temperature." Physical Review D 61, no. 7 (February 24, 2000). http://dx.doi.org/10.1103/physrevd.61.074014.

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Drukarev, E. G., M. G. Ryskin, and V. A. Sadovnikova. "Role of the in-medium four-quark condensates reexamined." Physical Review C 86, no. 3 (September 6, 2012). http://dx.doi.org/10.1103/physrevc.86.035201.

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Thomas, R., S. Zschocke, and B. Kämpfer. "Evidence for In-Medium Changes of Four-Quark Condensates." Physical Review Letters 95, no. 23 (November 28, 2005). http://dx.doi.org/10.1103/physrevlett.95.232301.

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Kadavý, Tomáš, Karol Kampf, and Jiří Novotný. "OPE of Green functions of chiral currents." Journal of High Energy Physics 2020, no. 10 (October 2020). http://dx.doi.org/10.1007/jhep10(2020)142.

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Abstract In this paper, we investigate the high-energy behavior of two-point and three-point Green functions of the QCD chiral currents and densities using the framework of the operator product expansion in the chiral limit. In detail, we study the contributions of the quark, gluon, quark-gluon and four-quark condensates to all the relevant non-vanishing three-point correlators.

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Journal articles on the topic 'Four-quark condensates'

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