Pions in nuclei, a probe of chiral symmetry restoration

Kienle, Paul; Yamazaki, T.

doi:10.1016/j.ppnp.2003.09.001

Cited by 78 publications

(54 citation statements)

References 58 publications

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Section: Pion Properties In Mediumcontrasting

confidence: 51%

“…As nuclear density increases, the in-medium pion decay constant f * π decreases, although the amount of the reduction may be larger than that calculated by the NJL model [20; 21]. However, in the treatment of the NJL model [20; 21], the decoupling of the time and space components of f * π is not clear with the presence of background matter, and may not directly be compared with our result, as well as the empirical value extracted from the pionic-atom experiment [18].In the following, we further discuss the in-medium "quark condensate" and the GMOR-like relation, just for an illustration. As we mentioned already, the present model is a light-front constituent quark model with the constituent quark mass of m q = 220 MeV in vacuum, and thus we cannot discuss the chiral limit (model limitation).…”

contrasting

confidence: 51%

“…[12]. Here, we note that the pion mass up to normal nuclear matter density is expected to be modified only slightly, where the modification δm π at nuclear density ρ = 0.17 fm −3 , averaged over the pion isospin states, is estimated as δm π ≃ +3 MeV [4;18;19;20;21]. Therefore, we approximate the effective pion mass in nuclear medium to be the same as in vacuum, m * π = m π , up to ρ = ρ 0 = 0.15 fm −3 , the maximum nuclear matter density treated.…”

Section: Pion Properties In Mediummentioning

confidence: 99%

Section: Pion Properties In Mediummentioning

confidence: 99%

“…As we mentioned already, the present model is a light-front constituent quark model with the constituent quark mass of m q = 220 MeV in vacuum, and thus we cannot discuss the chiral limit (model limitation). Keeping this point in mind, however, to get some idea, we simply write down the GMOR-like relation in vacuum and in medium, so that we try to compare the "quark condensate" value with that extracted experimentally [18]:Then, the ratio of the in-medium to vacuum quark condensates in the present approach may be estimated as,At normal nuclear matter density, ρ 0 (0.15 fm −3 ), the ratio gives ≃ 0.52 [12] (and also one can calculate by using the values listed in table 1, to be given next). This implies a larger reduction in "quark condensate" compared to the value 0.67 ± 0.06 extracted in Ref.…”

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confidence: 99%

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In-Medium Pion Valence Distribution Amplitude

Tsushima

Melo

2017

Few-Body Syst

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After a brief review of the quark-based model for nuclear matter, and some pion properties in medium presented in our previous works, we report new results for the pion valence wave function as well as the valence distribution amplitude in medium, which are presented in our recent article. We find that both the in-medium pion valence distribution and the in-medium pion valence wave function, are substantially modified at normal nuclear matter density, due to the reduction in the pion decay constant.Keywords In-medium pion properties · Form Factors · Distribution Amplitude IntroductionOne of the most exciting and challenging topics in hadronic physics is to study the modifications of hadron properties in nuclear medium, and to study how such modifications give impact on observables in medium. Since hadrons are composed of quarks, antiquarks and gluons, one can naturally expect that hadron internal structure would change when they are immersed in nuclear medium [1; 2; 3; 4; 5]. This question, becomes particularly interesting when it comes to that of pion. To be able to answer it, one first needs, simpler, effective quark-antiquark models of pion, which are successful in describing its properties in vacuum. Among such models, light-front constituent quark model has been very successful in describing the electromagnetic form factors, electromagnetic radii and decay constants of pion and kaon [6; 7; 8; 9; 10; 11]. Recent advances in experiments, indeed suggest to make it possible to access to the pion properties in a nuclear medium [3; 4; 5; 12; 13].Among the all hadrons, pion is the lightest, and it is believed as a Nambu-Goldstone boson, which is realized in nature emerged by the spontaneous breaking of chiral symmetry. This Nambu-Goldstone boson, pion, plays very important and special roles in hadronic and nuclear physics. However, because of its special properties, particularly the unusually light mass, it is not easy to describe the pion properties in medium as well as in vacuum based on naive quark models, even though such models can be successful in describing the other hadrons.Recently, we studied the properties of pion in nuclear medium [12; 13; 14], namely, the electromagnetic form factor, charge radius and weak decay constant, distribution amplitude (DA) by using a Below, we first briefly review the QMC model, the quark-based model of nuclear matter, to study the pion properties in medium. The QMC model was invented by Guichon [15] to describe the nuclear matter based on the quark degrees of freedom. The self-consistent exchange of the scalar-isoscalar σ and vector-isoscalar ω mean fields coupled directly to the relativistic confined quarks, are the key and novelty for the new saturation mechanism of nuclear matter. The model was extended to finite nuclei [16], and has successfully been applied for various nuclear and hadronic phenomena [3].The effective Lagrangian density for a uniform, spin-saturated, and isospin-symmetric nuclear system (symmetric nuclear matter) at the hadronic level is given...

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Section: Pion Properties In Mediumcontrasting

confidence: 51%

contrasting

confidence: 51%

Section: Pion Properties In Mediummentioning

confidence: 99%

Section: Pion Properties In Mediummentioning

confidence: 99%

mentioning

confidence: 99%

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In-Medium Pion Valence Distribution Amplitude

Tsushima

Melo

2017

Few-Body Syst

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New insight into nuclear structure from QCD

Thomas¹

2004

Ann. Phys.

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The natural building blocks of atomic nuclei within the framework of QCD are colorless clusters of quarks, with the quantum numbers of nucleons but with internal structure modified by the local mean scalar field. A key parameter of the nucleon in such an approach is the scalar polarizability, which characterizes the response of a nucleon to an applied scalar field. This response leads naturally to 3-, 4-and higher-body effective forces, each proportional to a higher power of the scalar polarizabilty. Recent progress on the important problem of chiral extrapolation of lattice QCD data suggests a way to estimate the scalar polarizability of the nucleon, with initial results consistent with successful phenomenlogical estimates. This may be seen as a first step in the struggle to derive nuclear structure from QCD itself.

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New insight into nuclear structure from QCD^*

Thomas

2004

Annalen der Physik

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The natural building blocks of atomic nuclei within the framework of QCD are colorless clusters of quarks, with the quantum numbers of nucleons but with internal structure modified by the local mean scalar field. A key parameter of the nucleon in such an approach is the scalar polarizability, which characterizes the response of a nucleon to an applied scalar field. This response leads naturally to 3‐, 4‐ and higher‐body effective forces, each proportional to a higher power of the scalar polarizabilty. Recent progress on the important problem of chiral extrapolation of lattice QCD data suggests a way to estimate the scalar polarizability of the nucleon, with initial results consistent with successful phenomenlogical estimates. This may be seen as a first step in the struggle to derive nuclear structure from QCD itself.

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Pions in nuclei, a probe of chiral symmetry restoration

Cited by 78 publications

References 58 publications

In-Medium Pion Valence Distribution Amplitude

In-Medium Pion Valence Distribution Amplitude

New insight into nuclear structure from QCD

New insight into nuclear structure from QCD^*

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Pions in nuclei, a probe of chiral symmetry restoration

Cited by 78 publications

References 58 publications

In-Medium Pion Valence Distribution Amplitude

In-Medium Pion Valence Distribution Amplitude

New insight into nuclear structure from QCD

New insight into nuclear structure from QCD*

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New insight into nuclear structure from QCD^*