suneel kumar - Academia.edu (original) (raw)

Papers by suneel kumar

Research paper thumbnail of Influence of isospin dependent nuclear charge radii on fragmentation in heavy ion collisions

Nuclear Physics A, 2014

ABSTRACT We study the initialization effects via nuclear charge radii on fragmentation for the wh... more ABSTRACT We study the initialization effects via nuclear charge radii on fragmentation for the whole mass range of periodic table by taking isospin asymmetric nuclear reactions using Isospin dependent Quantum Molecular Dynamics (IQMD) model. Calculations are performed for three different isospin dependent nuclear charge radii parameterizations as well as for liquid drop model (LDM) radius. Our study reveals that there is a significant role of nuclear charge radii on fragmentation in heavy ion collisions at intermediate energies. The influence on fragmentation due to initialization via nuclear charge radii is more for heavier colliding nuclei compared to lighter colliding nuclei and this influence further reduces with increase in incident energy for lighter colliding nuclei and remains nearly constant for heavier colliding nuclei. Moreover, isospin dependent radius is more suitable to reproduce experimental findings of INDRA collaboration.

Research paper thumbnail of On the role of density-dependent symmetry energy and momentum dependent interactions in multi-fragmentation

Physics of Particles and Nuclei Letters, 2012

The fragmentation of projectile and spectator matter is studied at different incident energies us... more The fragmentation of projectile and spectator matter is studied at different incident energies using an isospin-dependent QMD model with reduced isospin dependent cross-section. The sensitivity of the production of fragments is analyzed using different parametrizations of density dependence of symmetry energy. We shall also highlight the collective response of the momentum dependent interactions(MDI) and symmetry energy towards the fragmentation of colliding nuclei at intermediate energies. PACS numbers: 25.70.-z, 25.75.Ld

Research paper thumbnail of Rapidity distribution as a probe for elliptical flow at intermediate energies

Central European Journal of Physics, 2011

Interplay between the spectator and participant matter in heavy-ion collisions is investigated wi... more Interplay between the spectator and participant matter in heavy-ion collisions is investigated within isospin dependent quantum molecular dynamics (IQMD) model in term of rapidity distribution of light charged particles. The effect of different types and size rapidity distributions is studied in elliptical flow. The elliptical flow patterns show important role of the nearby * Electronic address:

Research paper thumbnail of On the momentum distribution of particles participating in nuclear stopping

Pramana, 2014

ABSTRACT Nuclear stopping is studied as a function of incident energy and charge of the fragment ... more ABSTRACT Nuclear stopping is studied as a function of incident energy and charge of the fragment produced in central heavy-ion collisions (HIC) of AuAu and NiNi using stopping parameter VARXZ. Various momentum constraints were imposed to get better insight into the stopping. The comparison of measured and calculated values of stopping for protons reveals the significance of these constraints. Maximum stopping is obtained for the particles lying in the lowest range of the momentum distribution at all incident energies.

Research paper thumbnail of Impact of momentum dependent equation of state and isospin-dependent cross-section on the neutron-proton Pt-differential elliptic flow

Research paper thumbnail of Effect of density-dependent symmetry energy on nuclear stopping

Journal of Physics G-nuclear and Particle Physics - J PHYS G-NUCL PARTICLE PHYS, 2012

Research paper thumbnail of Numerical modeling of compression ignition engine: A review

Renewable and Sustainable Energy Reviews, 2013

Research paper thumbnail of Fragment production in 16O+80Br reaction within dynamical microscopic theory

Pramana, 2002

We analyze the formation of fragments in O·Br reaction at different incident energies between E A... more We analyze the formation of fragments in O·Br reaction at different incident energies between E A 50 MeV and 200 MeV. This study is carried out within the quantum molecular dynamics (QMD) model coupled with recently advanced simulated annealing clusterization algorithm (SACA). For comparison, we also use the conventional minimum spanning tree (MST) method. Our detailed study shows that the SACA can detect the final stable fragment configuration as early as 60 fm/c which is marked by a dip in the heaviest fragment. On the other hand, the MST method needs several hundred fm/c to identify the final stable distribution. A comparison of the charge distribution with experimental data shows that the SACA is able to reproduce the data very nicely whereas (as reported earlier) the MST method fails to break the spectator matter into intermediate mass fragments. Furthermore, our results with SACA method indicate the onset of multi-fragmentation around 75 MeV/A which is again in good agreement with experimental findings.

Research paper thumbnail of A comparative study of model ingredients: Fragmentation in heavy-ion collisions using quantum molecular dynamics model

Pramana, 2010

We aim to understand the role of NN cross-sections, equation of state as well as different model ... more We aim to understand the role of NN cross-sections, equation of state as well as different model ingredients such as width of Gaussian, clusterisation range and different clusterisation algorithms in multifragmentation using quantum molecular dynamics model. We notice that all model ingredients have sizable effect on the fragment pattern.

Research paper thumbnail of On the elliptic flow for nearly symmetric collisions and nuclear equation of state

Pramana, 2011

We present the results of elliptic flow for the collision of nearly symmetric nuclei ( ) using th... more We present the results of elliptic flow for the collision of nearly symmetric nuclei ( ) using the quantum molecular dynamics (QMD) model. General features of elliptic flow are investigated with the help of theoretical simulations. The simulations are performed at beam energies between 45 and 105 MeV/nucleon. A significant change can be seen from in-plane to out-of-plane elliptic flow of different fragments with incident energy. A comparison with experimental data is also made. Further, we show that elliptic flow for different fragments follows power-law dependence as given by the function C(A tot ) τ .

Research paper thumbnail of Optimizing the rapidity limit for nuclear stopping in intermediate energy heavy-ion collisions

Physics of Atomic Nuclei, 2013

ABSTRACT

Research paper thumbnail of Binary breakup: Onset of multifragmentation and vaporization in Ca-Ca collisions

Physical Review C, 1998

The incomplete fusion, onset of multifragmentation and vaporization is studied in Ca-Ca collision... more The incomplete fusion, onset of multifragmentation and vaporization is studied in Ca-Ca collisions at bombarding energies between 20–1000 A MeV and at impact parameters between b=0 and b max . The simulations of Ca-Ca are performed using the quantum molecular dynamics ( ...

Research paper thumbnail of Medium mass fragment production due to momentum dependent interactions

Physical Review C, 2008

The role of system size and momentum dependent effects are analyzed in multifragmenation by simul... more The role of system size and momentum dependent effects are analyzed in multifragmenation by simulating symmetric reactions of Ca+Ca, Ni+Ni, Nb+Nb, Xe+Xe, Er+Er, Au+Au, and U+U at incident energies between 50 MeV/nucleon and 1000 MeV/nucleon and over full impact parameter zones. Our detailed study reveals that there exist a system size dependence when reaction is simulated with momentum dependent interactions. This dependence exhibits a mass power law behavior.

Research paper thumbnail of Momentum dependent interactions and the asymmetry of the reaction: Multifragmentation as an example

Physical Review C, 2001

We discuss the importance of momentum dependent interactions in explaining the multifragmentation... more We discuss the importance of momentum dependent interactions in explaining the multifragmentation in asymmetric reactions by comparing the results with 16 O-induced emulsion data. The reactions are simulated within a quantum molecular dynamics model and the clusterization is ...

Research paper thumbnail of Model ingredients and multifragmentation in symmetric and asymmetric heavy ion collisions

Physical Review C, 2000

The relative role of the momentum-dependent interactions and larger nucleon-nucleon cross section... more The relative role of the momentum-dependent interactions and larger nucleon-nucleon cross section is discussed in multifragmentation using quantum molecular dynamical model. We find that the sensitivity of the larger cross section towards multifragmentation reduces in the ...

Research paper thumbnail of Impact parameter dependence of the disappearance of flow and in-medium nucleon-nucleon cross section

Physical Review C, 1998

The impact parameter dependence of the disappearance of directed transverse flow has been investi... more The impact parameter dependence of the disappearance of directed transverse flow has been investigated for 40 Arϩ 45 Sc reactions using the Michigan State University 4 Array upgraded with the High Rate Array ͑HRA͒. The energy at which collective transverse flow in the reaction plane disappears, the balance energy (E bal ), is found to increase approximately linearly as a function of impact parameter. Comparison of our measured values of E bal (b) shows agreement with predictions of Quantum Molecular Dynamics ͑QMD͒ model calculations.

Research paper thumbnail of Different nucleon-nucleon cross sections and multifragmentation

Physical Review C, 1998

We present a systematic study of the dependence of the fragment production on the nucleon-nucleon... more We present a systematic study of the dependence of the fragment production on the nucleon-nucleon cross section using the quantum molecular dynamics model as an event generator. We employ constant energy-dependent and in-medium cross sections. In our ...

Research paper thumbnail of Correlation between balance energy and transition energy for symmetric colliding nuclei

Physical Review C, 2011

... The theoretical re-sults are compared with the experimental data extracted by the INDRA, FOPI... more ... The theoretical re-sults are compared with the experimental data extracted by the INDRA, FOPI, and Plastic Ball Collaborations [5,6]. With the increase in the incident energy, the elliptical flow v2 changes from ... C 82, 024610 (2010); S. Kumar and S. Kumar, Pramana J. Phys. ...

Research paper thumbnail of Influence of charge asymmetry and isospin-dependent cross section on elliptical flow

Physical Review C, 2012

Using the isospin dependent quantum molecular dynamics model, we study the effect of charge asymm... more Using the isospin dependent quantum molecular dynamics model, we study the effect of charge asymmetry and isospin dependent cross-section on nuclear stopping and multiplicity of free nucleons and LMF's. Simulations were carried out for the reactions 124 X m + 124 X m , where m varies from 47 to 59 and for 40 Y n + 40 Y n , where n varies from 14 to 23. Our study shows that nuclear stopping as well as the production of LMF's depend strongly on the isospin of the cross-section.

Research paper thumbnail of Influence of charge asymmetry and isospin-dependent cross section on nuclear stopping

Physical Review C, 2011

Using the isospin dependent quantum molecular dynamics model, we study the effect of charge asymm... more Using the isospin dependent quantum molecular dynamics model, we study the effect of charge asymmetry and isospin dependent cross-section on nuclear stopping and multiplicity of free nucleons and LMF's. Simulations were carried out for the reactions 124 X m + 124 X m , where m varies from 47 to 59 and for 40 Y n + 40 Y n , where n varies from 14 to 23. Our study shows that nuclear stopping as well as the production of LMF's depend strongly on the isospin of the cross-section.

Research paper thumbnail of Influence of isospin dependent nuclear charge radii on fragmentation in heavy ion collisions

Nuclear Physics A, 2014

ABSTRACT We study the initialization effects via nuclear charge radii on fragmentation for the wh... more ABSTRACT We study the initialization effects via nuclear charge radii on fragmentation for the whole mass range of periodic table by taking isospin asymmetric nuclear reactions using Isospin dependent Quantum Molecular Dynamics (IQMD) model. Calculations are performed for three different isospin dependent nuclear charge radii parameterizations as well as for liquid drop model (LDM) radius. Our study reveals that there is a significant role of nuclear charge radii on fragmentation in heavy ion collisions at intermediate energies. The influence on fragmentation due to initialization via nuclear charge radii is more for heavier colliding nuclei compared to lighter colliding nuclei and this influence further reduces with increase in incident energy for lighter colliding nuclei and remains nearly constant for heavier colliding nuclei. Moreover, isospin dependent radius is more suitable to reproduce experimental findings of INDRA collaboration.

Research paper thumbnail of On the role of density-dependent symmetry energy and momentum dependent interactions in multi-fragmentation

Physics of Particles and Nuclei Letters, 2012

The fragmentation of projectile and spectator matter is studied at different incident energies us... more The fragmentation of projectile and spectator matter is studied at different incident energies using an isospin-dependent QMD model with reduced isospin dependent cross-section. The sensitivity of the production of fragments is analyzed using different parametrizations of density dependence of symmetry energy. We shall also highlight the collective response of the momentum dependent interactions(MDI) and symmetry energy towards the fragmentation of colliding nuclei at intermediate energies. PACS numbers: 25.70.-z, 25.75.Ld

Research paper thumbnail of Rapidity distribution as a probe for elliptical flow at intermediate energies

Central European Journal of Physics, 2011

Interplay between the spectator and participant matter in heavy-ion collisions is investigated wi... more Interplay between the spectator and participant matter in heavy-ion collisions is investigated within isospin dependent quantum molecular dynamics (IQMD) model in term of rapidity distribution of light charged particles. The effect of different types and size rapidity distributions is studied in elliptical flow. The elliptical flow patterns show important role of the nearby * Electronic address:

Research paper thumbnail of On the momentum distribution of particles participating in nuclear stopping

Pramana, 2014

ABSTRACT Nuclear stopping is studied as a function of incident energy and charge of the fragment ... more ABSTRACT Nuclear stopping is studied as a function of incident energy and charge of the fragment produced in central heavy-ion collisions (HIC) of AuAu and NiNi using stopping parameter VARXZ. Various momentum constraints were imposed to get better insight into the stopping. The comparison of measured and calculated values of stopping for protons reveals the significance of these constraints. Maximum stopping is obtained for the particles lying in the lowest range of the momentum distribution at all incident energies.

Research paper thumbnail of Impact of momentum dependent equation of state and isospin-dependent cross-section on the neutron-proton Pt-differential elliptic flow

Research paper thumbnail of Effect of density-dependent symmetry energy on nuclear stopping

Journal of Physics G-nuclear and Particle Physics - J PHYS G-NUCL PARTICLE PHYS, 2012

Research paper thumbnail of Numerical modeling of compression ignition engine: A review

Renewable and Sustainable Energy Reviews, 2013

Research paper thumbnail of Fragment production in 16O+80Br reaction within dynamical microscopic theory

Pramana, 2002

We analyze the formation of fragments in O·Br reaction at different incident energies between E A... more We analyze the formation of fragments in O·Br reaction at different incident energies between E A 50 MeV and 200 MeV. This study is carried out within the quantum molecular dynamics (QMD) model coupled with recently advanced simulated annealing clusterization algorithm (SACA). For comparison, we also use the conventional minimum spanning tree (MST) method. Our detailed study shows that the SACA can detect the final stable fragment configuration as early as 60 fm/c which is marked by a dip in the heaviest fragment. On the other hand, the MST method needs several hundred fm/c to identify the final stable distribution. A comparison of the charge distribution with experimental data shows that the SACA is able to reproduce the data very nicely whereas (as reported earlier) the MST method fails to break the spectator matter into intermediate mass fragments. Furthermore, our results with SACA method indicate the onset of multi-fragmentation around 75 MeV/A which is again in good agreement with experimental findings.

Research paper thumbnail of A comparative study of model ingredients: Fragmentation in heavy-ion collisions using quantum molecular dynamics model

Pramana, 2010

We aim to understand the role of NN cross-sections, equation of state as well as different model ... more We aim to understand the role of NN cross-sections, equation of state as well as different model ingredients such as width of Gaussian, clusterisation range and different clusterisation algorithms in multifragmentation using quantum molecular dynamics model. We notice that all model ingredients have sizable effect on the fragment pattern.

Research paper thumbnail of On the elliptic flow for nearly symmetric collisions and nuclear equation of state

Pramana, 2011

We present the results of elliptic flow for the collision of nearly symmetric nuclei ( ) using th... more We present the results of elliptic flow for the collision of nearly symmetric nuclei ( ) using the quantum molecular dynamics (QMD) model. General features of elliptic flow are investigated with the help of theoretical simulations. The simulations are performed at beam energies between 45 and 105 MeV/nucleon. A significant change can be seen from in-plane to out-of-plane elliptic flow of different fragments with incident energy. A comparison with experimental data is also made. Further, we show that elliptic flow for different fragments follows power-law dependence as given by the function C(A tot ) τ .

Research paper thumbnail of Optimizing the rapidity limit for nuclear stopping in intermediate energy heavy-ion collisions

Physics of Atomic Nuclei, 2013

ABSTRACT

Research paper thumbnail of Binary breakup: Onset of multifragmentation and vaporization in Ca-Ca collisions

Physical Review C, 1998

The incomplete fusion, onset of multifragmentation and vaporization is studied in Ca-Ca collision... more The incomplete fusion, onset of multifragmentation and vaporization is studied in Ca-Ca collisions at bombarding energies between 20–1000 A MeV and at impact parameters between b=0 and b max . The simulations of Ca-Ca are performed using the quantum molecular dynamics ( ...

Research paper thumbnail of Medium mass fragment production due to momentum dependent interactions

Physical Review C, 2008

The role of system size and momentum dependent effects are analyzed in multifragmenation by simul... more The role of system size and momentum dependent effects are analyzed in multifragmenation by simulating symmetric reactions of Ca+Ca, Ni+Ni, Nb+Nb, Xe+Xe, Er+Er, Au+Au, and U+U at incident energies between 50 MeV/nucleon and 1000 MeV/nucleon and over full impact parameter zones. Our detailed study reveals that there exist a system size dependence when reaction is simulated with momentum dependent interactions. This dependence exhibits a mass power law behavior.

Research paper thumbnail of Momentum dependent interactions and the asymmetry of the reaction: Multifragmentation as an example

Physical Review C, 2001

We discuss the importance of momentum dependent interactions in explaining the multifragmentation... more We discuss the importance of momentum dependent interactions in explaining the multifragmentation in asymmetric reactions by comparing the results with 16 O-induced emulsion data. The reactions are simulated within a quantum molecular dynamics model and the clusterization is ...

Research paper thumbnail of Model ingredients and multifragmentation in symmetric and asymmetric heavy ion collisions

Physical Review C, 2000

The relative role of the momentum-dependent interactions and larger nucleon-nucleon cross section... more The relative role of the momentum-dependent interactions and larger nucleon-nucleon cross section is discussed in multifragmentation using quantum molecular dynamical model. We find that the sensitivity of the larger cross section towards multifragmentation reduces in the ...

Research paper thumbnail of Impact parameter dependence of the disappearance of flow and in-medium nucleon-nucleon cross section

Physical Review C, 1998

The impact parameter dependence of the disappearance of directed transverse flow has been investi... more The impact parameter dependence of the disappearance of directed transverse flow has been investigated for 40 Arϩ 45 Sc reactions using the Michigan State University 4 Array upgraded with the High Rate Array ͑HRA͒. The energy at which collective transverse flow in the reaction plane disappears, the balance energy (E bal ), is found to increase approximately linearly as a function of impact parameter. Comparison of our measured values of E bal (b) shows agreement with predictions of Quantum Molecular Dynamics ͑QMD͒ model calculations.

Research paper thumbnail of Different nucleon-nucleon cross sections and multifragmentation

Physical Review C, 1998

We present a systematic study of the dependence of the fragment production on the nucleon-nucleon... more We present a systematic study of the dependence of the fragment production on the nucleon-nucleon cross section using the quantum molecular dynamics model as an event generator. We employ constant energy-dependent and in-medium cross sections. In our ...

Research paper thumbnail of Correlation between balance energy and transition energy for symmetric colliding nuclei

Physical Review C, 2011

... The theoretical re-sults are compared with the experimental data extracted by the INDRA, FOPI... more ... The theoretical re-sults are compared with the experimental data extracted by the INDRA, FOPI, and Plastic Ball Collaborations [5,6]. With the increase in the incident energy, the elliptical flow v2 changes from ... C 82, 024610 (2010); S. Kumar and S. Kumar, Pramana J. Phys. ...

Research paper thumbnail of Influence of charge asymmetry and isospin-dependent cross section on elliptical flow

Physical Review C, 2012

Using the isospin dependent quantum molecular dynamics model, we study the effect of charge asymm... more Using the isospin dependent quantum molecular dynamics model, we study the effect of charge asymmetry and isospin dependent cross-section on nuclear stopping and multiplicity of free nucleons and LMF's. Simulations were carried out for the reactions 124 X m + 124 X m , where m varies from 47 to 59 and for 40 Y n + 40 Y n , where n varies from 14 to 23. Our study shows that nuclear stopping as well as the production of LMF's depend strongly on the isospin of the cross-section.

Research paper thumbnail of Influence of charge asymmetry and isospin-dependent cross section on nuclear stopping

Physical Review C, 2011

Using the isospin dependent quantum molecular dynamics model, we study the effect of charge asymm... more Using the isospin dependent quantum molecular dynamics model, we study the effect of charge asymmetry and isospin dependent cross-section on nuclear stopping and multiplicity of free nucleons and LMF's. Simulations were carried out for the reactions 124 X m + 124 X m , where m varies from 47 to 59 and for 40 Y n + 40 Y n , where n varies from 14 to 23. Our study shows that nuclear stopping as well as the production of LMF's depend strongly on the isospin of the cross-section.