x-dependence of the quark distribution functions in the χCQMconfig

Dahiya, Harleen; Gupta, Madhur

doi:10.1140/epjc/s10052-007-0419-z

Cited by 22 publications

(26 citation statements)

References 55 publications

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“…In Figure 1, we show the strange antiquark distribution in the kaon, according to the present model, using the initial parameterizations given by Olness et al [6] and by Dahyia and Gupta [7]. The result is close to the parameterization for the kaon considered inRef.…”

Section: P(uud) -> A{uds) -\-K(us)supporting

confidence: 70%

“…In the work of Dahiya and Gupta [7], no strangeness asymmetry in the constituent quarks is assumed. They have used the strangeness distribution function FIGURE 1.…”

Section: P(uud) -> A{uds) -\-K(us)mentioning

confidence: 99%

“…They have used the strangeness distribution function FIGURE 1. The strange anti-quark distribution in the kaon, using the present approach with initial parameterizations of Olness et al [6] (solid-line) and Dahyia-Gupta [7] (dashed-line).…”

Section: P(uud) -> A{uds) -\-K(us)mentioning

confidence: 99%

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On the Kaon’ s̄ structure function from the strangeness asymmetry in the nucleon

Trevisan¹,

Mirez²,

Tomio³

et al. 2009

AIP Conference Proceedings

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Abstract. We propose a phenomenological approach based in the meson cloud model to obtain the strange quark structure function inside a kaon, considering the strange quark asymmetry inside the nucleon.Keywords: Kaon, strange quark, structure function, asymmetry PACS: 13.75. Jz, 11.30.Hv, 12.39.x, 14.65.Bt The experimental data from CCFR and NuTeV collaborations [1] show that the distribution function for strange and anti-strange quark are asymmetric. If we consider only gluon splitting processes, such asymmetry cannot be found, since the quarks generated by gluons should have the same momentum distribution. So, among the models that have been proposed (or considered) to explain the asymmetry, the most popular are based on meson clouds or A -K fluctuations [2,3]. By using this kind of model, we analyze the behavior of some parameterizations for the strange quark distribution s(x), in terms of the Bjorken scale x, and discuss how to estimate the structure function for a constituent quark in a Kaon.The strange quark distribution in the nucleon sea, as well as the distribution for u and d quarks, can be separated into perturbative and nonperturbative parts. The perturbative part, due to short range fluctuations of the gluon field, cannot contribute to the s -s asymmetry. So, the observed asymmetry is expected to result from nonperturbative processes, such as a meson-baryon configuration. In the meson-baryon configuration, there are processes where the nucleon oscillates to a baryon plus a meson, such as, p(uud) -> A.{uds) -\-K(us).For instance, the contribution to strange quark distribution comes from the valence s quark in the A and the s in the kaon. The phenomenological approach we consider here is the same one used in Ref.[4] to explain the u -d behavior. Instead of n + or n 0 , we have K + or K0. The formalism is explained in the following. As in [5] we describe the meson composed by a valence quark surrounded by a cloud of partons that is locally colorless and electrically neutral. But the cloud contains some of momentum of the constituent quark. So, the quark in our model have effective degrees of freedom with substructure. The structure function of the constituent quark/antiquark can be extracted

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Section: P(uud) -> A{uds) -\-K(us)supporting

confidence: 70%

“…In the work of Dahiya and Gupta [7], no strangeness asymmetry in the constituent quarks is assumed. They have used the strangeness distribution function FIGURE 1.…”

Section: P(uud) -> A{uds) -\-K(us)mentioning

confidence: 99%

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On the Kaon’ s̄ structure function from the strangeness asymmetry in the nucleon

Trevisan¹,

Mirez²,

Tomio³

et al. 2009

AIP Conference Proceedings

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“…The χCQM uses the effective interaction Lagrangian approach of the strong interactions where the effective degrees of freedom are the valence quarks and the internal Goldstone bosons (GBs) which are coupled to the valence quarks [22][23][24][25]. The χCQM successfully explains the "proton spin problem" [25], magnetic moments of octet and decuplet baryons including their transitions [26], account for the violation of Gottfried Sum Rule [27] and Coleman-Glashow sum rule, hyperon β decay parameters [28], strangeness content in the nucleon [29], magnetic moments of 1 2 − octet baryon resonances [30], magnetic moments of 1 2 − and 3 2 − Λ resonances [31], charge radii [32], quadrupole moment [33], etc.. The model is successfully extended to predict the important role played by the small intrinsic charm content in the nucleon spin in the SU(4) χCQM [34] and to calculate the magnetic moment and charge radii of spin 1 2 + and spin 3 2 + charm baryons including their radiative decays [35,36].…”

Section: Introductionmentioning

confidence: 99%

Axial-vector form factors for the low lying octet baryons in the chiral quark constituent model

Dahiya

Randhawa

2014

Phys. Rev. D

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We have calculated the axial-vector form factors of the low lying octet baryons (N , Σ, Ξ and Λ) in the chiral constituent quark model (χCQM). In particular, we have studied the implications of chiral symmetry breaking and SU(3) symmetry breaking for the singlet (g 0 A ) and non-singlet (g 3 A and g 8 A ) axial-vector coupling constants expressed as combinations of the spin polarizations at zero momentum transfer. The conventional dipole form of parametrization has been used to analyse the Q 2 dependence of the axial-vector form factors (G 0 A (Q 2 ), G 3 A (Q 2 ) and G 8 A (Q 2 )). The total strange singlet and non-singlet contents (G 0 s (Q 2 ), G 3 s (Q 2 ) and G 8 s (Q 2 )) of the nucleon determining the strange quark contribution to the nucleon spin (∆s) have also been discussed.

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“…The integral of the quark distribution functions [30] incorporating the strangeness content in the χCQM are expressed as [21,26] …”

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confidence: 99%

Spin and flavor strange quark content of the nucleon

Dahiya

Gupta

2008

Phys. Rev. D

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Several spin and flavor dependent parameters characterizing the strangeness content of the nucleon have been calculated in the chiral constituent quark model with configuration mixing (χCQM config ) which is known to provide a satisfactory explanation of the "proton spin crisis" and related issues. In particular, we have calculated the strange spin polarization ∆s, the strangeness contribution to the weak axial vector couplings ∆ 8 etc., strangeness contribution to the magnetic moments µ(p) s etc., the strange quark flavor fraction f s , the strangeness dependent quark flavor whereas a recent phenomenology study with lattice inputs [7] also predicts a very small value for the strange magnetic moment, µ(p) s = −0.046 ± 0.19µ N . In the naive constituent quark model (CQM) [8,9,10], µ(p) s is predicted to be zero. The broader question of contribution of strangeness in the nucleon has also been discussed by several authors recently [11]. It is widely recognized that a knowledge about the strangeness content of the nucleon would undoubtedly provide vital clues to the non-perturbative aspects of QCD.The existence of strangeness in the nucleon has been indicated in the context of low energy experiments [12,13] whereas it has been observed in the deep inelastic scattering (DIS) experiments [14,15,16,17]. In the context of DIS, the strange spin polarization of the nucleon [18] looks to be well established through the measurements of polarized structure functions of the nucleon [15,16,17]. Apart from the observations of DIS data regarding strangeness dependent spin polarization functions, several interesting facts have also been revealed regarding the quark flavor distribution functions in the DIS experiments.In particular, the NuSea Collaboration −0.053 . In the context of low energy experiments, the large pion-nucleon sigma term value [13] indicating non zero strange quark flavor fraction f s is also indicative of the presence of strange quarks in the nucleon although there is no consensus regarding the various mechanisms which can contribute to f s [20]. Therefore, the indications of the strange quark degree of freedom in DIS as well as low energy experiments provide a strong motivation to examine the strangeness 2 contribution to the nucleon thereby giving vital clues to the non-perturbative effects of QCD.One may think that the strangeness content of the nucleon perhaps can be obtained through the generation of "quark sea" perturbatively from the quark-pair production by gluons. However, this kind of "sea" is symmetric w.r.t.ū andd [21], negated by the observed value ofū −d asymmetry [19]. Therefore, one has to consider the "quark sea" produced by the non-perturbative mechanism. One such model which can yield an adequate description of the "quark sea" generation through the chiral fluctuations is the chiral constituent quark model (χCQM) [22] which is not only successful in giving a satisfactory explanation of "proton spin crisis" [23] but is also able to account for the violation of Gottfried Sum Rule [21,2...

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x-dependence of the quark distribution functions in the χCQMconfig

Cited by 22 publications

References 55 publications

On the Kaon’ s̄ structure function from the strangeness asymmetry in the nucleon

On the Kaon’ s̄ structure function from the strangeness asymmetry in the nucleon

Axial-vector form factors for the low lying octet baryons in the chiral quark constituent model

Spin and flavor strange quark content of the nucleon

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