Virtual Meson Cloud of the Nucleon and Intrinsic Strangeness and Charm

Paiva, S.; Nielsen, M.; Navarra, F. S.; Durães, F. O.; Barz, Ligia Liani

doi:10.1142/s0217732398002886

Cited by 58 publications

(51 citation statements)

References 25 publications

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“…considerably smaller than the prediction of Paiva et al [109] as well as other earlier theoretical predictions [104,107] although the result is similar to that of Ref. [112].…”

Section: S/s Asymmetrysupporting

confidence: 89%

“…The difference between the s and s distributions determined by the CCFR collaboration [22] has been studied in the context of meson cloud models [109,110,111,112] and has been modeled by gluon splitting into s and s quarks with different effective masses [107]. Meson cloud models tend to produce larger differences between s(x) and s(x) than can be accommodated by the data, leading Ji and Tang to suggest that the strange sea is highly localized [107].…”

Section: Strange Sea Summarymentioning

confidence: 99%

“…This led to the speculation that charm could be generated in the sea by a higher-twist mechanism. Two nonperturbative models of charm in the sea are discussed here, intrinsic charm [114] and the meson cloud model [109,124].…”

Section: Nonperturbative Heavy Quarksmentioning

confidence: 99%

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Physics of the Nucleon Sea Quark Distributions

Vogt¹

2000

Progress in Particle and Nuclear Physics

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Sea quark distributions in the nucleon have naively been expected to be generated perturbatively by gluon splitting. In this case, there is no reason for the light quark and anti-quark sea distributions to be different. No asymmetries in the strange or heavy quark sea distributions are predicted in the improved parton model. However, recent experiments have called these naive expectations into question. A violation of the Gottfried sum rule has been measured in several experiments, suggesting that u < d in the proton. Additionally, other measurements, while not definitive, show that there may be an asymmetry in the strange and anti-strange quark sea distributions. These effects may require nonperturbative explanations. In this review we first discuss the perturbative aspects of the sea quark distributions. We then describe the experiments that could point to nonperturbative contributions to the nucleon sea. Current phenomenological models that could explain some of these effects are reviewed.

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“…considerably smaller than the prediction of Paiva et al [109] as well as other earlier theoretical predictions [104,107] although the result is similar to that of Ref. [112].…”

Section: S/s Asymmetrysupporting

confidence: 89%

Section: Strange Sea Summarymentioning

confidence: 99%

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Physics of the Nucleon Sea Quark Distributions

Vogt¹

2000

Progress in Particle and Nuclear Physics

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“…However, a purely perturbative, extrinsic, treatment for the heavy quarks might not be adequate; several models indeed postulate a non-perturbative, intrinsic, heavy quark component e.g. light-cone [2,3] and meson cloud models [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Intrinsic bottom and its impact on heavy new physics at the LHC

Lyonnet

2016

EPJ Web of Conferences

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Abstract. Heavy quark parton distribution functions (PDFs) play an important role in several Standard Model and New Physics processes. Most analyses rely on the assumption that the charm and bottom PDFs are generated perturbatively by gluon splitting and do not involve any non-perturbative degrees of freedom. On the other hand, non-perturbative, intrinsic heavy quark parton distributions have been predicted in the literature. We demonstrate that to a very good approximation the scale-evolution of the intrinsic heavy quark content of the nucleon is governed by non-singlet evolution equations. This allows to analyze the intrinsic heavy quark distributions without having to resort to a full-fledged global analysis of parton distribution functions. We exploit this freedom to model intrinsic bottom distributions which are so far missing in the literature. We estimate the impact of the non-perturbative contribution to the charm and bottom-quark PDFs and on several important parton-parton luminosities at the LHC.

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“…In the model proposed by Brodsky, Hoyer, Peterson and Sakay (BHPS) [11], the creation of the Q Q pair was studied in detail (for a discussion of other models for the IHQ see Refs. [12][13][14][15]). It was assumed that the nucleon light cone wave function has higher Fock states, the first one being |qqq Q Q>.…”

mentioning

confidence: 99%

Phenomenological implications of the intrinsic charm in the Z boson production at the LHC

Bailas

Gonçalves

2016

Eur. Phys. J. C

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In this paper we study the Z , Z + jet, Z + c, and Z + c+ jet production in pp collisions at the LHC considering different models for the intrinsic charm content of the proton. We analyze the impact of the intrinsic charm in the rapidity and transverse momentum distributions for these different processes. Our results indicated that differently from the other processes, the Z +c cross section is strongly affected by the presence of the intrinsic charm. Moreover, we propose the analysis of the ratiosand we demonstrate that these observables can be used as a probe of the intrinsic charm.A complete knowledge of the partonic structure of the hadrons is fundamental to make predictions for the Standard Model and to beyond Standard Model processes at hadron colliders. Since the early days of the parton model and of the first deep inelastic scattering (DIS) experiments, determining the precise form of the quark and gluon distributions of the nucleon has been a major goal of high energy hadron physics. Over the last 40 years huge progress has been achieved. In particular, data from HERA have dramatically improved our knowledge as regards the small-x behavior of the parton distributions functions (PDFs) [1]. Another important improvement has occurred to our knowledge for the heavy quark contribution to the proton structure [2]. In the last years several groups have proposed different schemes to determine these distributions considering that the heavy quark component in PDFs can be perturbatively generated by gluon splitting (see e.g. [3]). This component is usually denoted the extrinsic heavy quark component. Moreover, the possibility of an intrinsic component has been studied in detail and included in the recent versions of the PDF parametrizations [4][5][6][7]. The hypothesis of intrinsic heavy quarks (IHQ) is a a e-mails: barros@ufpel.edu.br;victor.goncalves@thep.lu.se natural consequence of the quantum fluctuations inherent to Quantum Chromodynamics (QCD) and amounts to assuming the existence of a QQ (Q = c, b, t) as a non-perturbative component in the hadron wave function. A comprehensive review of the main characteristics of the IHQ models can be found in [8][9][10]. In the model proposed by Brodsky, Hoyer, Peterson and Sakay (BHPS) [11], the creation of the Q Q pair was studied in detail (for a discussion of other models for the IHQ see Refs. [12][13][14][15]). It was assumed that the nucleon light cone wave function has higher Fock states, the first one being |qqq Q Q>. The probability of finding the nucleon in this configuration was given by the inverse of the squared invariant mass of the system. Because of the heavy quark mass, this probability as a function of the quark fractional momentum, P(x), is very hard, as compared to the one obtained through the DGLAP evolution. Although this model predicts the x dependence of the intrinsic components, its normalization should be constrained by fitting the experimental data and still is an open question. In particular, two recent global analysis of the PDFs [5,...

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Virtual Meson Cloud of the Nucleon and Intrinsic Strangeness and Charm

Cited by 58 publications

References 25 publications

Physics of the Nucleon Sea Quark Distributions

Physics of the Nucleon Sea Quark Distributions

Intrinsic bottom and its impact on heavy new physics at the LHC

Phenomenological implications of the intrinsic charm in the Z boson production at the LHC

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