Carlos Bertulani | Texas A&M University - Commerce (original) (raw)
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Papers by Carlos Bertulani
Acta Physica Polonica B, 2014
Phys Rev C, Feb 27, 2007
I show that the disintegration of weakly-bound nuclei and the ionization of weakly-bound atomic e... more I show that the disintegration of weakly-bound nuclei and the ionization of weakly-bound atomic electrons due to their interaction with leptons from beta decay is a negligible effect.
We study the efiect of the spreading widths on the excitation probabilities of the double giant d... more We study the efiect of the spreading widths on the excitation probabilities of the double giant dipole resonance. We solve the coupled-channels equations for the excitation of the giant dipole resonance and the double giant dipole resonance. TakingPb+Pbcollisions as example, we study the resulting efiect on the excitation amplitudes, and cross sections as a function of the width of the
We study the effect of the spreading widths on the excitation probabilities of the double giant d... more We study the effect of the spreading widths on the excitation probabilities of the double giant dipole resonance. We solve the coupled-channels equations for the excitation of the giant dipole resonance and the double giant dipole resonance. Taking Pb+Pb collisions as example, we study the resulting effect on the excitation amplitudes, and cross sections as a function of the width
Aps Meeting Abstracts, Apr 1, 2005
The S-factors (S17 for the radiative capture reaction p+^7 Be->^8B+γ are calculated using ab init... more The S-factors (S17 for the radiative capture reaction p+^7 Be->^8B+γ are calculated using ab initio no-core shell model (NCSM) overlap integrals with corrected asymptotics. Momentum distributions for the reactions ^8B (41 MeV/nucleon) + ^9Be->^7Be+X and ^8B (936 MeV/nucleon) + ^12C->^7Be+X have also been studied. A good description of both the experimental data of both the astrophysical S-factor and of the momentum distributions over a wide energy/momentum spectrum is obtained. The spectroscopic factors obtained with the NCSM wavefunctions are also shown to be in good agreement with the experimental data. Our studies support a value of S17 in agreement with recent Coulomb dissociation experiments, but which are slightly below the averaged values from direct capture experiments [1]. [1] W.C. Haxton, P.D. Parker, C.E. Rolfs, archive preprint nucl- th/0501020.
Progress of Theoretical Physics, Apr 1, 2010
The continuum-discretized coupled-channels (CDCC) method is used to study the breakup of weakly-b... more The continuum-discretized coupled-channels (CDCC) method is used to study the breakup of weakly-bound nuclei at intermediate energies collisions. For large impact parameters, the Eikonal CDCC (E-CDCC) method was applied. The effects of Lorentz contraction on the nuclear and Coulomb potentials have been investigated in details. Such effects tend to increase cross sections appreciably. We also show that, for loosely-bound nuclei, the contribution of the so-called close field is small and can be neglected.
Phys Rev C, 2002
At high energies a quark-gluon plasma is expected to be formed in heavy-ion collisions at the Rel... more At high energies a quark-gluon plasma is expected to be formed in heavy-ion collisions at the Relativistic Heavy-Ion Collider and the Large Hadron Collider. The theoretical description of these processes is directly associated to a complete knowledge of the details of medium effects in the nuclear gluon distribution. In this paper we analyze the possibility to constrain the behavior of this distribution considering peripheral heavy ion collisions. We reanalyze the photoproduction of heavy quarks for the deduction of the in-medium gluon distribution using three current parametrizations for this parton distribution. Moreover, we show that the elastic photoproduction of vector mesons is a potential process to probe the nuclear gluon distribution.
Eur Phys J a, 1988
The high flux of equivalent photons present in relativistic heavy ion collisions of two charges Z... more The high flux of equivalent photons present in relativistic heavy ion collisions of two charges Z 1 and Z 2 gives rise to the collision of two equivalent photons. The cross-sections for various processes are directly related to the corresponding γ- γ cross-sections. As compared to γ- γ physics being studied at e+ e- colliders, we find that high energy states will not be so easily accessible at the existing facilities, however, the enhancement factor ( Z 1 Z 2)2 in the expression for the cross section will provide very large photon fluxes for lower energies.
J Phys G Nucl Particle Phys, 1998
A new class of giant resonances in nuclei is discussed, i.e. giant resonances built on other gian... more A new class of giant resonances in nuclei is discussed, i.e. giant resonances built on other giant resonances. These resonances are observed with very large cross sections in relativistic heavy ion collisions. A great experimental and theoretical effort is underway to understand the reaction mechanism which leads to the excitation of these states in nuclei, as well as the better microscopic understanding of their properties, for example, strength, energy centroids, widths and anharmonicities.
Phys Rev C, 1992
We investigate the longitudinal and transverse momentum distributions of charged fragments origin... more We investigate the longitudinal and transverse momentum distributions of charged fragments originating from reactions with radioactive, neutron-rich beams. It is shown that the width of the narrow peak of the longitudinal momentum distribution is insensitive to the details of the collision and the size of the target nucleus. In contrast, the width of the peripheral region from which transversely moving particles originate is significantly narrowed via absorption of the outgoing neutrons. This diffractively broadens the width of their transverse momentum distribution, in a manner which depends on details of the collision, and so makes the transverse distribution less reliable than the longitudinal one for measuring the size of the original neutron halo.
Physical Review C Nuclear Physics, May 1, 2007
I show that the disintegration of weakly-bound nuclei and the ionization of weakly-bound atomic e... more I show that the disintegration of weakly-bound nuclei and the ionization of weakly-bound atomic electrons due to their interaction with leptons from β decay is a negligible effect.
Aps Division of Nuclear Physics Meeting Abstracts, Oct 1, 2004
A new method for treating breakup processes of rare isotope projectiles is presented. The scatter... more A new method for treating breakup processes of rare isotope projectiles is presented. The scattering wavefunctions are treated in the eikonal approximation whereas the intrinsic nuclear wavefunction is discretised to account for continuum-continuum couplings. It is shown that the method yields high accuracy and computational speed. Relativistic effects are included and shown to be crucial for reactions with radioactive beams at intermediate energies. The validity of this method is tested in reactions of relevance for rare isotope facilities.
Acta Physica Hungarica a Heavy Ion Physics, 2004
I discuss a few of the recent developments in nuclear reactions at very low energies with emphasi... more I discuss a few of the recent developments in nuclear reactions at very low energies with emphasis on the role of radioactive beam facilities.
Accurate nuclear reaction rates are needed for primordial nucleosynthesis and hydrostatic burning... more Accurate nuclear reaction rates are needed for primordial nucleosynthesis and hydrostatic burning in stars. The relevant reactions are extremely difficult to measure directly in the laboratory at the small astrophysical energies. In recent years direct reactions have been developed and applied to extract low-energy astrophysical S-factors. These methods require a combination of new experimental techniques and theoretical efforts, which are the subject of this presentation. In this talk I will discuss the role of continuum states and their mutual coupling in extracting the nuclear astrophysical information from experimental data carried out at radioactive beam facilities.
Few Body Systems, Jan 31, 2015
This is a brief review of few relevant topics on tunneling of composite particles and how the cou... more This is a brief review of few relevant topics on tunneling of composite particles and how the coupling to intrinsic and external degrees of freedom affects tunneling probabilities. I discuss the phenomena of resonant tunneling, different barriers seen by subsystems, damping of resonant tunneling by level bunching and continuum effects due to particle dissociation.
Journal of Physics G Nuclear and Particle Physics, Sep 1, 1999
We study the breakup of 9Li projectiles in high-energy (28.5 MeV/u) collisions with heavy nuclear... more We study the breakup of 9Li projectiles in high-energy (28.5 MeV/u) collisions with heavy nuclear targets (208Pb). The wavefunctions are calculated using a simple potential model for 9Li. A good agreement with the measured data is obtained with insignificant E2 contribution.
Phys Rev C, 1997
We critically discuss the recently developed quantum-mechanical equivalent photon spectrum by Ben... more We critically discuss the recently developed quantum-mechanical equivalent photon spectrum by Benesh et al. [Phys. Rev. C 54, 1404 (1996)]. We point out that the key point, the strong absorption in heavy ion collisions, is not treated adequately. Conclusions drawn from such a spectrum are invalid. Equivalent-photon spectra appropriate for heavy ions have been given before in quantal, as well as semiclassical versions, and were found to be very satisfactory.
Acta Physica Polonica B, 2014
Phys Rev C, Feb 27, 2007
I show that the disintegration of weakly-bound nuclei and the ionization of weakly-bound atomic e... more I show that the disintegration of weakly-bound nuclei and the ionization of weakly-bound atomic electrons due to their interaction with leptons from beta decay is a negligible effect.
We study the efiect of the spreading widths on the excitation probabilities of the double giant d... more We study the efiect of the spreading widths on the excitation probabilities of the double giant dipole resonance. We solve the coupled-channels equations for the excitation of the giant dipole resonance and the double giant dipole resonance. TakingPb+Pbcollisions as example, we study the resulting efiect on the excitation amplitudes, and cross sections as a function of the width of the
We study the effect of the spreading widths on the excitation probabilities of the double giant d... more We study the effect of the spreading widths on the excitation probabilities of the double giant dipole resonance. We solve the coupled-channels equations for the excitation of the giant dipole resonance and the double giant dipole resonance. Taking Pb+Pb collisions as example, we study the resulting effect on the excitation amplitudes, and cross sections as a function of the width
Aps Meeting Abstracts, Apr 1, 2005
The S-factors (S17 for the radiative capture reaction p+^7 Be->^8B+γ are calculated using ab init... more The S-factors (S17 for the radiative capture reaction p+^7 Be->^8B+γ are calculated using ab initio no-core shell model (NCSM) overlap integrals with corrected asymptotics. Momentum distributions for the reactions ^8B (41 MeV/nucleon) + ^9Be->^7Be+X and ^8B (936 MeV/nucleon) + ^12C->^7Be+X have also been studied. A good description of both the experimental data of both the astrophysical S-factor and of the momentum distributions over a wide energy/momentum spectrum is obtained. The spectroscopic factors obtained with the NCSM wavefunctions are also shown to be in good agreement with the experimental data. Our studies support a value of S17 in agreement with recent Coulomb dissociation experiments, but which are slightly below the averaged values from direct capture experiments [1]. [1] W.C. Haxton, P.D. Parker, C.E. Rolfs, archive preprint nucl- th/0501020.
Progress of Theoretical Physics, Apr 1, 2010
The continuum-discretized coupled-channels (CDCC) method is used to study the breakup of weakly-b... more The continuum-discretized coupled-channels (CDCC) method is used to study the breakup of weakly-bound nuclei at intermediate energies collisions. For large impact parameters, the Eikonal CDCC (E-CDCC) method was applied. The effects of Lorentz contraction on the nuclear and Coulomb potentials have been investigated in details. Such effects tend to increase cross sections appreciably. We also show that, for loosely-bound nuclei, the contribution of the so-called close field is small and can be neglected.
Phys Rev C, 2002
At high energies a quark-gluon plasma is expected to be formed in heavy-ion collisions at the Rel... more At high energies a quark-gluon plasma is expected to be formed in heavy-ion collisions at the Relativistic Heavy-Ion Collider and the Large Hadron Collider. The theoretical description of these processes is directly associated to a complete knowledge of the details of medium effects in the nuclear gluon distribution. In this paper we analyze the possibility to constrain the behavior of this distribution considering peripheral heavy ion collisions. We reanalyze the photoproduction of heavy quarks for the deduction of the in-medium gluon distribution using three current parametrizations for this parton distribution. Moreover, we show that the elastic photoproduction of vector mesons is a potential process to probe the nuclear gluon distribution.
Eur Phys J a, 1988
The high flux of equivalent photons present in relativistic heavy ion collisions of two charges Z... more The high flux of equivalent photons present in relativistic heavy ion collisions of two charges Z 1 and Z 2 gives rise to the collision of two equivalent photons. The cross-sections for various processes are directly related to the corresponding γ- γ cross-sections. As compared to γ- γ physics being studied at e+ e- colliders, we find that high energy states will not be so easily accessible at the existing facilities, however, the enhancement factor ( Z 1 Z 2)2 in the expression for the cross section will provide very large photon fluxes for lower energies.
J Phys G Nucl Particle Phys, 1998
A new class of giant resonances in nuclei is discussed, i.e. giant resonances built on other gian... more A new class of giant resonances in nuclei is discussed, i.e. giant resonances built on other giant resonances. These resonances are observed with very large cross sections in relativistic heavy ion collisions. A great experimental and theoretical effort is underway to understand the reaction mechanism which leads to the excitation of these states in nuclei, as well as the better microscopic understanding of their properties, for example, strength, energy centroids, widths and anharmonicities.
Phys Rev C, 1992
We investigate the longitudinal and transverse momentum distributions of charged fragments origin... more We investigate the longitudinal and transverse momentum distributions of charged fragments originating from reactions with radioactive, neutron-rich beams. It is shown that the width of the narrow peak of the longitudinal momentum distribution is insensitive to the details of the collision and the size of the target nucleus. In contrast, the width of the peripheral region from which transversely moving particles originate is significantly narrowed via absorption of the outgoing neutrons. This diffractively broadens the width of their transverse momentum distribution, in a manner which depends on details of the collision, and so makes the transverse distribution less reliable than the longitudinal one for measuring the size of the original neutron halo.
Physical Review C Nuclear Physics, May 1, 2007
I show that the disintegration of weakly-bound nuclei and the ionization of weakly-bound atomic e... more I show that the disintegration of weakly-bound nuclei and the ionization of weakly-bound atomic electrons due to their interaction with leptons from β decay is a negligible effect.
Aps Division of Nuclear Physics Meeting Abstracts, Oct 1, 2004
A new method for treating breakup processes of rare isotope projectiles is presented. The scatter... more A new method for treating breakup processes of rare isotope projectiles is presented. The scattering wavefunctions are treated in the eikonal approximation whereas the intrinsic nuclear wavefunction is discretised to account for continuum-continuum couplings. It is shown that the method yields high accuracy and computational speed. Relativistic effects are included and shown to be crucial for reactions with radioactive beams at intermediate energies. The validity of this method is tested in reactions of relevance for rare isotope facilities.
Acta Physica Hungarica a Heavy Ion Physics, 2004
I discuss a few of the recent developments in nuclear reactions at very low energies with emphasi... more I discuss a few of the recent developments in nuclear reactions at very low energies with emphasis on the role of radioactive beam facilities.
Accurate nuclear reaction rates are needed for primordial nucleosynthesis and hydrostatic burning... more Accurate nuclear reaction rates are needed for primordial nucleosynthesis and hydrostatic burning in stars. The relevant reactions are extremely difficult to measure directly in the laboratory at the small astrophysical energies. In recent years direct reactions have been developed and applied to extract low-energy astrophysical S-factors. These methods require a combination of new experimental techniques and theoretical efforts, which are the subject of this presentation. In this talk I will discuss the role of continuum states and their mutual coupling in extracting the nuclear astrophysical information from experimental data carried out at radioactive beam facilities.
Few Body Systems, Jan 31, 2015
This is a brief review of few relevant topics on tunneling of composite particles and how the cou... more This is a brief review of few relevant topics on tunneling of composite particles and how the coupling to intrinsic and external degrees of freedom affects tunneling probabilities. I discuss the phenomena of resonant tunneling, different barriers seen by subsystems, damping of resonant tunneling by level bunching and continuum effects due to particle dissociation.
Journal of Physics G Nuclear and Particle Physics, Sep 1, 1999
We study the breakup of 9Li projectiles in high-energy (28.5 MeV/u) collisions with heavy nuclear... more We study the breakup of 9Li projectiles in high-energy (28.5 MeV/u) collisions with heavy nuclear targets (208Pb). The wavefunctions are calculated using a simple potential model for 9Li. A good agreement with the measured data is obtained with insignificant E2 contribution.
Phys Rev C, 1997
We critically discuss the recently developed quantum-mechanical equivalent photon spectrum by Ben... more We critically discuss the recently developed quantum-mechanical equivalent photon spectrum by Benesh et al. [Phys. Rev. C 54, 1404 (1996)]. We point out that the key point, the strong absorption in heavy ion collisions, is not treated adequately. Conclusions drawn from such a spectrum are invalid. Equivalent-photon spectra appropriate for heavy ions have been given before in quantal, as well as semiclassical versions, and were found to be very satisfactory.