scholarly journals CONSTITUENT QUARKS AND THE SPIN OF THE PROTON

2009 ◽  
Vol 24 (27) ◽  
pp. 2167-2174 ◽  
Author(s):  
H. FRITZSCH ◽  
G. ELDAHOUMI
Keyword(s):  
Internal Structure ◽  
Bound States ◽  
Spin Structure ◽  
Constituent Quark ◽  
Valence Quark

The constituent quarks are interpreted as bound states, which have an internal structure. The quark distributions of the proton are related to those of the constituent quarks. The experiments support this hypothesis. Likewise the spin structure of the proton is related to the spin structure of the constituent quarks. We find that about 30% of the spin of a constituent quark is given by the valence quark, and 70% are provided by the gluons.

scholarly journals LEADING EFFECTS IN HADROPRODUCTIONS OF ΛcAND D FROM CONSTITUENT QUARK–DIQUARK CASCADE PICTURE

2004 ◽  
Vol 19 (04) ◽  
pp. 599-611 ◽  
Author(s):  
TSUTOMU TASHIRO ◽  
SHIN-ICHI NAKARIKI ◽  
HUJIO NODA ◽  
KISEI KINOSHITA ◽  
SHUXIN LAN
Keyword(s):  
Constituent Quark ◽  
Valence Quark ◽  
Cascade Model

We discuss the hadroproductions of Λc, [Formula: see text], D and [Formula: see text] in the framework of the constituent quark–diquark cascade model taking into account the valence quark annihilation. The spectra of Λcand [Formula: see text] in pA, Σ-A and π-A collisions are well explained by the model using the values of parameters used in hadroproductions of D and [Formula: see text]. It is shown that the role of valence diquark in the incident baryon is important for [Formula: see text] productions as well as for Λcproduction.

scholarly journals NEUTRON SPIN STRUCTURE STUDY AT JEFFERSON LAB HALL A

2003 ◽  
Vol 18 (08) ◽  
pp. 1153-1160
Author(s):  
JIAN-PING CHEN
Keyword(s):  
Spin Structure ◽  
Spin Asymmetry ◽  
Valence Quark ◽  
Structure Study ◽  
Precision Measurements ◽  
Neutron Spin ◽  
Higher Twist Effects ◽  
Jefferson Lab ◽  
Neutron Spin Structure ◽  
Bjorken X

With a high-intensity highly-polarized 6 GeV electron beam, and a high-density polarized 3 He target, we have carried out a number of experiments to study the neutron spin structure at Hall A in Jefferson Lab. Taking advantage of the high luminosity of Jefferson Lab, we completed two inclusive deep-inelastic-scattering experiments this summer. In the first precision measurements were made of the spin asymmetry [Formula: see text] in the valence quark (high Bjorken x) region, and in the second higher-twist effects were studied via precision measurements of [Formula: see text]. Physics motivation and preliminary results from the first experiment will be presented and discussed. I will also present nearly final results from an earlier experiment, which measured the generalized GDH sum for the neutron in the Q 2 range of 0.1 to 1 GeV 2. Planned near-term experiments will be briefly discussed.

scholarly journals ANTI-HYPERON POLARIZATION IN pA AND Σ-A COLLISIONS AND INTRINSIC ANTIDIQUARK STATE IN INCIDENT BARYON

2012 ◽  
Vol 21 (01) ◽  
pp. 1250001
Author(s):  
HUJIO NODA ◽  
TSUTOMU TASHIRO ◽  
SHIN-ICHI NAKARIKI
Keyword(s):  
Constituent Quark ◽  
Valence Quark ◽  
Cascade Model ◽  
The Other ◽  
Other Hand ◽  
Incident Nucleon

We discuss the relation between the polarization of inclusively produced (anti)hyperons and the incident baryon states in the framework of the constituent quark–diquark cascade model. We assume that there is an intrinsic diquark–antidiquark state in the incident baryon, in which the intrinsic diquark immediately fragments into a non-leading baryon and the antidiquark behaves as a valence constituent. It is also assumed that the valence (anti)diquark in the incident nucleon tends to combine selectively with a spin-down sea quark and, on the other hand, the spin-up valence quark in the projectile is chosen by a sea (anti)diquark in preference to the spin-down valence quark. It is found that the incident spin-1/2 baryon is mainly composed of a spin-0 valence diquark and a valence quark, and contains an intrinsic diquark–antidiquark state with a probability of about 7%.

UNPOLARIZED NUCLEON STRUCTURE FUNCTIONS IN THE NAMBU-JONA-LASINIO CHIRAL SOLITON MODEL

1996 ◽  
Vol 11 (38) ◽  
pp. 3021-3034 ◽  
Author(s):  
H. WEIGEL ◽  
L. GAMBERG ◽  
H. REINHARDT
Keyword(s):  
Constituent Quark ◽  
Valence Quark ◽  
Parton Model ◽  
Structure Functions ◽  
Nucleon Structure ◽  
Quark Masses ◽  
Model Interpretation ◽  
Chiral Soliton ◽  
Quark Level ◽  
Chiral Soliton Model

We study nucleon structure functions within the bosonized Nambu-Jona-Lasinio model where the nucleon emerges as a chiral soliton. As examples we present the unpolarized structure functions for the νp and [Formula: see text] scattering and discuss the Gottfried sum rule in the valence quark approximation. This approximation is justified for moderate constituent quark masses (~ 400 MeV) as the valence quark level dominates the predictions of nucleon properties. We find that these structure functions are well localized in the interval 0≤x Bj ≤1 permitting a parton model interpretation.

scholarly journals Doubly charmed multibaryon systems

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
H. Garcilazo ◽  
A. Valcarce
Keyword(s):  
Quark Model ◽  
Bound States ◽  
Constituent Quark ◽  
Constituent Quark Model ◽  
Heavy Quarks ◽  
Separation Energy ◽  
Quantum Numbers ◽  
Body State

Abstract We study two- and three-baryon systems with two units of charm looking for possible bound states or resonances. All two-baryon interactions are consistently derived from a constituent quark model tuned in the light-flavor hadron phenomenology: spectra and interactions. The presence of the heavy quarks makes the two-body interactions simpler than in the light-flavor sector. Our results show a narrow two-body resonance with quantum numbers $$(I,J^P)=(0,0^+)$$(I,JP)=(0,0+). It is located 6.2 MeV below the $$\Sigma _c\Sigma _c$$ΣcΣc threshold and has a width of 4.7 MeV. The foregoing two-body state contributes to generate a $$N \Sigma _c\Sigma _c$$NΣcΣc resonance with quantum numbers $$(I,J^P)=(1/2,1/2^+)$$(I,JP)=(1/2,1/2+) and a separation energy of 0.2 MeV.

HYPERON POLARIZATION IN QUARK-DIQUARK CASCADE MODEL

2007 ◽  
Vol 16 (07n08) ◽  
pp. 2344-2349
Author(s):  
TSUTOMU TASHIRO ◽  
HUJIO NODA ◽  
SHIN-ICHI NAKARIKI ◽  
KAZUMI FUKUMA
Keyword(s):  
Wave Function ◽  
Constituent Quark ◽  
Valence Quark ◽  
Cascade Model ◽  
Proton Proton ◽  
Particle Effect ◽  
Quantization Axis ◽  
Leading Particle

We relate the hyperon polarizations in proton-proton and proton-nucleus collisions to the leading particle effect and use the constituent quark-diquark cascade model with SU(6) wave function. We assume that the quantization axis is characterized by the production normal of the leading baryon of the most massive cascade chain and the incident valence diquark tends to pick up a spin down sea quark or conversely a sea diquark preferentially combines with the spin up incident valence quark to form a leading baryon as compared with the spin down valence quark.

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