We compute the rate for diffractive ϕ electro-production using the Color Glass Condensate dipole ... more We compute the rate for diffractive ϕ electro-production using the Color Glass Condensate dipole model. The model parameters are obtained from fits to the most recent combined HERA data on inclusive deep inelastic scattering. As for the ϕ meson, we use an AdS/QCD holographic light front wavefunction. Our predictions are compared to the available data collected at the HERA collider.
Proceedings of XXIV International Workshop on Deep-Inelastic Scattering and Related Subjects — PoS(DIS2016)
We predict the cross-section for diffractive φ electroproduction within the dipole model, using a... more We predict the cross-section for diffractive φ electroproduction within the dipole model, using a holographic meson wavefunction for the φ. For the dipole crosssection, we use the Color Glass Condensate dipole model whose parameters are fitted to the latest 2015 combined HERA data on Deep Inelastic Scattering. Choosing a strange quark mass of 0.14 GeV, we find good agreement with the available data.
Proceedings of Light Cone 2010: Relativistic Hadronic and Particle Physics — PoS(LC2010)
The electromagnetic form factors are the most fundamental quantities to describe the internal str... more The electromagnetic form factors are the most fundamental quantities to describe the internal structure of the nucleon and the shape of a spatially extended particle is determined by its intrinsic quadrupole moment which is first order moment of the charge density operator. With some experimental indications of a deformed nucleon, we have calculated the intrinsic quadrupole moment of the octet and decuplet baryons in the framework of chiral constituent quark model χCQM which is quite successful in explaining some of the important baryon properties in the nonperturbative regime.
We investigate the gravitational form factors (GFFs) and the longitudinal momentum densities (p +... more We investigate the gravitational form factors (GFFs) and the longitudinal momentum densities (p + densities) for proton in a light-front quark-diquark model. The light-front wave functions are constructed from the soft-wall AdS/QCD prediction. The contributions from both the scalar and the axial vector diquarks are considered here. The results are compared with the consequences of a parametrization of nucleon generalized parton distributions (GPDs) in the light of recent MRST measurements of parton distribution functions (PDFs) and a soft-wall AdS/QCD model. The spatial distribution of angular momentum for up and down quarks inside the nucleon has been presented. At the density level, we illustrate different definitions of angular momentum explicitly for an up and down quark in the light-front quark-diquark model inspired by AdS/QCD.
We use an anti-de Sitter/quantum chromodynamics holographic light-front wave function for the ρ a... more We use an anti-de Sitter/quantum chromodynamics holographic light-front wave function for the ρ and ϕ mesons, in conjunction with the color glass condensate dipole cross section whose parameters are fitted to the most recent 2015 high precision HERA data on inclusive deep inelastic scattering, in order to predict the cross sections for diffractive ρ and ϕ electroproduction. Our results suggest that the holographic meson light-front wave function is able to give a simultaneous description of ρ and ϕ production data provided we use a set of light quark masses with m u;d < m s ≈ 0.14 GeV.
We revisit the model for parametrization of momentum dependence of nucleon generalized parton dis... more We revisit the model for parametrization of momentum dependence of nucleon generalized parton distributions in the light of recent MRST measurements of parton distribution functions [1]. Our parametrization method with minimum set of free parameters give a sufficiently good description of data for Dirac and Pauli electromagnetic form factors of proton and neutron at small and intermediate values of momentum transfer. We also calculate the GPDs for up and down quark by decomposing the electromagnetic form factors for nucleon using the charge and isospin symmetry and also study the evolution of GPDs to a higher scale. We further investigate the transverse charge densities for both the unpolarized and transversely polarized nucleon and compare our results with the Kelly's distribution.
We compute the rate for diffractive φ electro-production using the Color Glass Condensate dipole ... more We compute the rate for diffractive φ electro-production using the Color Glass Condensate dipole model. The model parameters are obtained from fits to the most recent combined HERA data on inclusive deep inelastic scattering. As for the φ meson, we use an AdS/QCD holographic light front wavefunction. Our predictions are compared to the available data collected at the HERA collider.
The electromagnetic form factors have attracted lot of theoretical and experimental attention rec... more The electromagnetic form factors have attracted lot of theoretical and experimental attention recently as they encode extensive information on the internal structure of the hadron. An understanding of the form factors is necessary to describe the strong interactions as they are sensitive to the pion cloud and provide a test for the QCD inspired effective field theories based on the chiral symmetry. In view of the very exciting recent developments in the field, we propose to apply the techniques of chiral constituent quark model to measure the electromagnetic form factors of the nucleon.The results obtained are comparable to the latest experimental studies and also show improvement over some theoretical interpretations.
The weak decays of charmed baryon multiplets into ground state baryons and mesons are investigate... more The weak decays of charmed baryon multiplets into ground state baryons and mesons are investigated using current algebra technique. Some of the interesting results on the partial decays= rates and the asymmetry parameters for the ∆C=∆S=-1 mode are calculated and consequences discussed.
We incorporate the perturbative evolution effects in the generalized parton distributions (GPDs) ... more We incorporate the perturbative evolution effects in the generalized parton distributions (GPDs) calculated in effective light-front quark model for the nucleon. The perturbative effects enters into formalism through the evolution of GPDs according to the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi-like (DGLAP) equation. We obtain the evolved GPDs in the momentum space and transverse impact parameter space. We observe that combining the light front quark model with the perturbative evolution effects, give the effective model for studying the phenomenological GPDs.
The effects of nonperturbatively generated "quark sea" have been investigated to determine the fl... more The effects of nonperturbatively generated "quark sea" have been investigated to determine the flavor structure of the octet baryons. The chiral constituent quark model (χCQM), which is known to provide a satisfactory explanation of the proton spin and related issues in the nonperturbative regime, is able to explain the qualitative generation of the requisite amount of quark sea. The importance of quark sea has been studied at different values of the Bjorken scaling variable x by including it phenomenologically in the sea quark distribution functions. The results for the quark sea asymmetries liked(x) −ū(x), d(x)/ū(x) and Gottfried integral for the octet baryons strengthen the significance of quark sea at lower values of x.
We have calculated the strangeness contribution to the magnetic moments of the nucleon and $\Delt... more We have calculated the strangeness contribution to the magnetic moments of the nucleon and $\Delta$ decuplet baryons in the chiral constituent quark model with configuration mixing ($\chi$CQM$_{{\rm config}}$) which is known to provide a satisfactory explanation of the proton spin crisis and related issues. Our results are consistent with the recent experimental observations.
The magnetic moments of the negative parity octet resonances with spin {1/2}: $N^*$(1535), $N^*$(... more The magnetic moments of the negative parity octet resonances with spin {1/2}: $N^*$(1535), $N^*$(1650), $\Sigma^*$(1620), and $\Xi^*$(1690) have been calculated within the framework of the chiral constituent quark model. In this approach, the presence of the polarized $q\bar{q}$ pairs (or the meson cloud, in other words) is considered by using the Lagrangian for Goldstone boson emission from the constituent quarks. Further, the explicit contributions coming from the spin and orbital angular momentum, including the effects of the configurations mixing between the states with different spins, are obtained. The motivation for these calculations comes from the recent interest in experimental measurement of the magnetic moment of the ${S_{11}(1535)}$ resonance and of similar calculations being done within lattice quantum chromodynamics approaches. Our results can be compared with those expected to come from these sources.
We present a numerical analysis of helicity independent nucleon generalized parton distributions ... more We present a numerical analysis of helicity independent nucleon generalized parton distributions (GPDs) using the known formalism based on inclusion of higher Fock states in the soft-wall approach of the anti-de Sitter/QCD model. We calculate the momentum space GPDs by matching the electromagnetic form factors in the AdS model to the sum rules in QCD. We investigate their Mellin moments, transverse impact parameter GPDs, transverse mean square radius, and transverse width. We further extend this work to investigate the charge and anomalous magnetization densities for both unpolarized and transversely polarized nucleons. A comparison of results on density functions with phenomenological parametrization is also presented.
The electromagnetic form factors are the most fundamental quantities to describe the internal str... more The electromagnetic form factors are the most fundamental quantities to describe the internal structure of the nucleon and the shape of a spatially extended particle is determined by its intrinsic quadrupole moment which can be related to the charge radii. We have calculated the electromagnetic form factors, nucleon charge radii and the intrinsic quadrupole moment of the nucleon in the framework of chiral constituent quark model. The results obtained are comparable to the latest experimental studies and also show improvement over some theoretical interpretations.
The magnetic moments of spin 1 2 + and spin 3 2 + charmed baryons have been calculated in chiral ... more The magnetic moments of spin 1 2 + and spin 3 2 + charmed baryons have been calculated in chiral constituent quark model (χCQM). The effects of configuration mixing and quark masses have also been investigated. The results are not only in good agreement with existing experimental data but also show improvement over other phenomenological models.
The charge radii of the octet and decuplet baryons have been calculated in the framework of chira... more The charge radii of the octet and decuplet baryons have been calculated in the framework of chiral constituent quark model (χCQM) using a general parameterization (GP) method. Our results are comparable with the latest experimental studies as well as with other phenomenological models. The effects of SU(3) symmetry breaking and GP parameters pertaining to the one-, twoand three-quark contributions have also been investigated in detail.
The chiral constituent quark model (χCQM) has been extended to calculate the flavor structure of ... more The chiral constituent quark model (χCQM) has been extended to calculate the flavor structure of the nucleon through the meson-nucleon sigma terms which have large contributions from the quark sea and are greatly affected by chiral symmetry breaking and SU(3) symmetry breaking. The hidden strangeness component in the nucleon has also been investigated and its significant contribution is found to be consistent with the recent available experimental observations.
We compute the rate for diffractive ϕ electro-production using the Color Glass Condensate dipole ... more We compute the rate for diffractive ϕ electro-production using the Color Glass Condensate dipole model. The model parameters are obtained from fits to the most recent combined HERA data on inclusive deep inelastic scattering. As for the ϕ meson, we use an AdS/QCD holographic light front wavefunction. Our predictions are compared to the available data collected at the HERA collider.
Proceedings of XXIV International Workshop on Deep-Inelastic Scattering and Related Subjects — PoS(DIS2016)
We predict the cross-section for diffractive φ electroproduction within the dipole model, using a... more We predict the cross-section for diffractive φ electroproduction within the dipole model, using a holographic meson wavefunction for the φ. For the dipole crosssection, we use the Color Glass Condensate dipole model whose parameters are fitted to the latest 2015 combined HERA data on Deep Inelastic Scattering. Choosing a strange quark mass of 0.14 GeV, we find good agreement with the available data.
Proceedings of Light Cone 2010: Relativistic Hadronic and Particle Physics — PoS(LC2010)
The electromagnetic form factors are the most fundamental quantities to describe the internal str... more The electromagnetic form factors are the most fundamental quantities to describe the internal structure of the nucleon and the shape of a spatially extended particle is determined by its intrinsic quadrupole moment which is first order moment of the charge density operator. With some experimental indications of a deformed nucleon, we have calculated the intrinsic quadrupole moment of the octet and decuplet baryons in the framework of chiral constituent quark model χCQM which is quite successful in explaining some of the important baryon properties in the nonperturbative regime.
We investigate the gravitational form factors (GFFs) and the longitudinal momentum densities (p +... more We investigate the gravitational form factors (GFFs) and the longitudinal momentum densities (p + densities) for proton in a light-front quark-diquark model. The light-front wave functions are constructed from the soft-wall AdS/QCD prediction. The contributions from both the scalar and the axial vector diquarks are considered here. The results are compared with the consequences of a parametrization of nucleon generalized parton distributions (GPDs) in the light of recent MRST measurements of parton distribution functions (PDFs) and a soft-wall AdS/QCD model. The spatial distribution of angular momentum for up and down quarks inside the nucleon has been presented. At the density level, we illustrate different definitions of angular momentum explicitly for an up and down quark in the light-front quark-diquark model inspired by AdS/QCD.
We use an anti-de Sitter/quantum chromodynamics holographic light-front wave function for the ρ a... more We use an anti-de Sitter/quantum chromodynamics holographic light-front wave function for the ρ and ϕ mesons, in conjunction with the color glass condensate dipole cross section whose parameters are fitted to the most recent 2015 high precision HERA data on inclusive deep inelastic scattering, in order to predict the cross sections for diffractive ρ and ϕ electroproduction. Our results suggest that the holographic meson light-front wave function is able to give a simultaneous description of ρ and ϕ production data provided we use a set of light quark masses with m u;d < m s ≈ 0.14 GeV.
We revisit the model for parametrization of momentum dependence of nucleon generalized parton dis... more We revisit the model for parametrization of momentum dependence of nucleon generalized parton distributions in the light of recent MRST measurements of parton distribution functions [1]. Our parametrization method with minimum set of free parameters give a sufficiently good description of data for Dirac and Pauli electromagnetic form factors of proton and neutron at small and intermediate values of momentum transfer. We also calculate the GPDs for up and down quark by decomposing the electromagnetic form factors for nucleon using the charge and isospin symmetry and also study the evolution of GPDs to a higher scale. We further investigate the transverse charge densities for both the unpolarized and transversely polarized nucleon and compare our results with the Kelly's distribution.
We compute the rate for diffractive φ electro-production using the Color Glass Condensate dipole ... more We compute the rate for diffractive φ electro-production using the Color Glass Condensate dipole model. The model parameters are obtained from fits to the most recent combined HERA data on inclusive deep inelastic scattering. As for the φ meson, we use an AdS/QCD holographic light front wavefunction. Our predictions are compared to the available data collected at the HERA collider.
The electromagnetic form factors have attracted lot of theoretical and experimental attention rec... more The electromagnetic form factors have attracted lot of theoretical and experimental attention recently as they encode extensive information on the internal structure of the hadron. An understanding of the form factors is necessary to describe the strong interactions as they are sensitive to the pion cloud and provide a test for the QCD inspired effective field theories based on the chiral symmetry. In view of the very exciting recent developments in the field, we propose to apply the techniques of chiral constituent quark model to measure the electromagnetic form factors of the nucleon.The results obtained are comparable to the latest experimental studies and also show improvement over some theoretical interpretations.
The weak decays of charmed baryon multiplets into ground state baryons and mesons are investigate... more The weak decays of charmed baryon multiplets into ground state baryons and mesons are investigated using current algebra technique. Some of the interesting results on the partial decays= rates and the asymmetry parameters for the ∆C=∆S=-1 mode are calculated and consequences discussed.
We incorporate the perturbative evolution effects in the generalized parton distributions (GPDs) ... more We incorporate the perturbative evolution effects in the generalized parton distributions (GPDs) calculated in effective light-front quark model for the nucleon. The perturbative effects enters into formalism through the evolution of GPDs according to the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi-like (DGLAP) equation. We obtain the evolved GPDs in the momentum space and transverse impact parameter space. We observe that combining the light front quark model with the perturbative evolution effects, give the effective model for studying the phenomenological GPDs.
The effects of nonperturbatively generated "quark sea" have been investigated to determine the fl... more The effects of nonperturbatively generated "quark sea" have been investigated to determine the flavor structure of the octet baryons. The chiral constituent quark model (χCQM), which is known to provide a satisfactory explanation of the proton spin and related issues in the nonperturbative regime, is able to explain the qualitative generation of the requisite amount of quark sea. The importance of quark sea has been studied at different values of the Bjorken scaling variable x by including it phenomenologically in the sea quark distribution functions. The results for the quark sea asymmetries liked(x) −ū(x), d(x)/ū(x) and Gottfried integral for the octet baryons strengthen the significance of quark sea at lower values of x.
We have calculated the strangeness contribution to the magnetic moments of the nucleon and $\Delt... more We have calculated the strangeness contribution to the magnetic moments of the nucleon and $\Delta$ decuplet baryons in the chiral constituent quark model with configuration mixing ($\chi$CQM$_{{\rm config}}$) which is known to provide a satisfactory explanation of the proton spin crisis and related issues. Our results are consistent with the recent experimental observations.
The magnetic moments of the negative parity octet resonances with spin {1/2}: $N^*$(1535), $N^*$(... more The magnetic moments of the negative parity octet resonances with spin {1/2}: $N^*$(1535), $N^*$(1650), $\Sigma^*$(1620), and $\Xi^*$(1690) have been calculated within the framework of the chiral constituent quark model. In this approach, the presence of the polarized $q\bar{q}$ pairs (or the meson cloud, in other words) is considered by using the Lagrangian for Goldstone boson emission from the constituent quarks. Further, the explicit contributions coming from the spin and orbital angular momentum, including the effects of the configurations mixing between the states with different spins, are obtained. The motivation for these calculations comes from the recent interest in experimental measurement of the magnetic moment of the ${S_{11}(1535)}$ resonance and of similar calculations being done within lattice quantum chromodynamics approaches. Our results can be compared with those expected to come from these sources.
We present a numerical analysis of helicity independent nucleon generalized parton distributions ... more We present a numerical analysis of helicity independent nucleon generalized parton distributions (GPDs) using the known formalism based on inclusion of higher Fock states in the soft-wall approach of the anti-de Sitter/QCD model. We calculate the momentum space GPDs by matching the electromagnetic form factors in the AdS model to the sum rules in QCD. We investigate their Mellin moments, transverse impact parameter GPDs, transverse mean square radius, and transverse width. We further extend this work to investigate the charge and anomalous magnetization densities for both unpolarized and transversely polarized nucleons. A comparison of results on density functions with phenomenological parametrization is also presented.
The electromagnetic form factors are the most fundamental quantities to describe the internal str... more The electromagnetic form factors are the most fundamental quantities to describe the internal structure of the nucleon and the shape of a spatially extended particle is determined by its intrinsic quadrupole moment which can be related to the charge radii. We have calculated the electromagnetic form factors, nucleon charge radii and the intrinsic quadrupole moment of the nucleon in the framework of chiral constituent quark model. The results obtained are comparable to the latest experimental studies and also show improvement over some theoretical interpretations.
The magnetic moments of spin 1 2 + and spin 3 2 + charmed baryons have been calculated in chiral ... more The magnetic moments of spin 1 2 + and spin 3 2 + charmed baryons have been calculated in chiral constituent quark model (χCQM). The effects of configuration mixing and quark masses have also been investigated. The results are not only in good agreement with existing experimental data but also show improvement over other phenomenological models.
The charge radii of the octet and decuplet baryons have been calculated in the framework of chira... more The charge radii of the octet and decuplet baryons have been calculated in the framework of chiral constituent quark model (χCQM) using a general parameterization (GP) method. Our results are comparable with the latest experimental studies as well as with other phenomenological models. The effects of SU(3) symmetry breaking and GP parameters pertaining to the one-, twoand three-quark contributions have also been investigated in detail.
The chiral constituent quark model (χCQM) has been extended to calculate the flavor structure of ... more The chiral constituent quark model (χCQM) has been extended to calculate the flavor structure of the nucleon through the meson-nucleon sigma terms which have large contributions from the quark sea and are greatly affected by chiral symmetry breaking and SU(3) symmetry breaking. The hidden strangeness component in the nucleon has also been investigated and its significant contribution is found to be consistent with the recent available experimental observations.
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Papers by Neetika sharma