Pub Date : 2002-03-01DOI: 10.1556/APH.16.2002.1-4.37
H. C. Wu, M. Aristizábal, W. Ponce
This work studies the relevance of nuclear structure in the nonmesonic weak decay of Λ-hypernuclei, with the mechanism of ΛN → NN transition being restricted to one pion exchange (OPE) only. As an application, for the hypernucleus Λ 12 C a comparison between the L-S coupling and the j-j coupling gives an estimate of the range of nuclear structure effects. A considerable dependence is found of the total decay rate and the ratio Г n /qG p on the single particle properties of nuclear models. The possible contribution from the ΔI = 3/2 channel is investigated in a phenomenological manner.
本文研究了Λ-hypernuclei非介子弱衰变中核结构的相关性，其中ΛN→NN跃迁机制仅限于一次介子交换(OPE)。作为一个应用，对于超核Λ 12c, L-S耦合和j-j耦合的比较给出了核结构效应范围的估计。发现总衰变率和比值Г n /qG p与核模型的单粒子性质有相当大的关系。以现象学的方式研究了ΔI = 3/2通道的可能贡献。
{"title":"Is nuclear structure relevant to non-mesonic hypernuclear weak decay?","authors":"H. C. Wu, M. Aristizábal, W. Ponce","doi":"10.1556/APH.16.2002.1-4.37","DOIUrl":"https://doi.org/10.1556/APH.16.2002.1-4.37","url":null,"abstract":"This work studies the relevance of nuclear structure in the nonmesonic weak decay of Λ-hypernuclei, with the mechanism of ΛN → NN transition being restricted to one pion exchange (OPE) only. As an application, for the hypernucleus Λ 12 C a comparison between the L-S coupling and the j-j coupling gives an estimate of the range of nuclear structure effects. A considerable dependence is found of the total decay rate and the ratio Г n /qG p on the single particle properties of nuclear models. The possible contribution from the ΔI = 3/2 channel is investigated in a phenomenological manner.","PeriodicalId":7004,"journal":{"name":"Acta Physica Hungarica","volume":"34 1","pages":"347-358"},"PeriodicalIF":0.0,"publicationDate":"2002-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79709983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-03-01DOI: 10.1556/APH.16.2002.1-4.16
A. Ayala, E. Cuautle, Luis Manuel Monta o, G. Herrera
We study the polarization of Λ0’s produced in ultrarelativistic heavy-ion collisions. We argue that when the density of participants in the reaction is below the critical value for the production of a Quark-Gluon Plasma (QGP), recombination processes dominate the Λ0 production cross section and hence, Λ0’s are polarized. However, when the density of participants is above the critical value for QGP formation, coalescence processes dominate Λ0 production, giving rise to a reduction in the Λ0 polarization. For densities below the critical density for QGP production, we describe Λ0 polarization in terms of the DeGrand-Miettinen model and correct for the effects introduced by multiple scattering of the produced Λ0 within the nuclear environment.
{"title":"Λ0 polarization in ultrarelativistic nucleus-nucleus collisions","authors":"A. Ayala, E. Cuautle, Luis Manuel Monta o, G. Herrera","doi":"10.1556/APH.16.2002.1-4.16","DOIUrl":"https://doi.org/10.1556/APH.16.2002.1-4.16","url":null,"abstract":"We study the polarization of Λ0’s produced in ultrarelativistic heavy-ion collisions. We argue that when the density of participants in the reaction is below the critical value for the production of a Quark-Gluon Plasma (QGP), recombination processes dominate the Λ0 production cross section and hence, Λ0’s are polarized. However, when the density of participants is above the critical value for QGP formation, coalescence processes dominate Λ0 production, giving rise to a reduction in the Λ0 polarization. For densities below the critical density for QGP production, we describe Λ0 polarization in terms of the DeGrand-Miettinen model and correct for the effects introduced by multiple scattering of the produced Λ0 within the nuclear environment.","PeriodicalId":7004,"journal":{"name":"Acta Physica Hungarica","volume":"23 1","pages":"141-152"},"PeriodicalIF":0.0,"publicationDate":"2002-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83295742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-03-01DOI: 10.1556/aph.16.2002.1-4.12
J. Rapaport
The measurement of complete sets of spin transfer coefficients in nuclear transitions, induced via charge-exchange (((vec p, vec n))) reactions at intermediate energies, is a unique form of separating the spin-dependent and spin-independent contributions to the differential cross section. The two components of the spin-dependent contribution, the spin-longitudinal and spin-transverse components may equally be separated. This is extremely important in cases where the target nuclei has a non-integer ground state spin. In this study and as an example of the above, we present differential cross section and complete set of polarization transfer coefficients obtained in the ((^{13} C(vec p, vec n))) 13N reaction studied at angles between 0° and 33° and at 197 MeV incident proton energy. Polarization transfer coefficients are used to obtain the fraction of the Gamow-Teller (GT) component in the mirror ground state transition, which is a combination of the spin-independent Fermi (F) and spin-dependent GT components. Data are also presented for the transition to the first excited state in 13N at 2.34 MeV. This is a (1/2)− → (1/2)+ transition and the cross section is an incoherent admixture of ΔJ π = 1− and ΔJ π = 0− components. The complete set of polarization transfer coefficients are used to obtain differential cross section data for both components. The empirical results are compared with Distorted Wave Impulse Approximation calculations, DWIA.
{"title":"Spin Transfer Measurements in $(vec{p},vec{n})$ Reactions","authors":"J. Rapaport","doi":"10.1556/aph.16.2002.1-4.12","DOIUrl":"https://doi.org/10.1556/aph.16.2002.1-4.12","url":null,"abstract":"The measurement of complete sets of spin transfer coefficients in nuclear transitions, induced via charge-exchange (((vec p, vec n))) reactions at intermediate energies, is a unique form of separating the spin-dependent and spin-independent contributions to the differential cross section. The two components of the spin-dependent contribution, the spin-longitudinal and spin-transverse components may equally be separated. This is extremely important in cases where the target nuclei has a non-integer ground state spin. In this study and as an example of the above, we present differential cross section and complete set of polarization transfer coefficients obtained in the ((^{13} C(vec p, vec n))) 13N reaction studied at angles between 0° and 33° and at 197 MeV incident proton energy. Polarization transfer coefficients are used to obtain the fraction of the Gamow-Teller (GT) component in the mirror ground state transition, which is a combination of the spin-independent Fermi (F) and spin-dependent GT components. Data are also presented for the transition to the first excited state in 13N at 2.34 MeV. This is a (1/2)− → (1/2)+ transition and the cross section is an incoherent admixture of ΔJ π = 1− and ΔJ π = 0− components. The complete set of polarization transfer coefficients are used to obtain differential cross section data for both components. The empirical results are compared with Distorted Wave Impulse Approximation calculations, DWIA.","PeriodicalId":7004,"journal":{"name":"Acta Physica Hungarica","volume":"4 1","pages":"105-111"},"PeriodicalIF":0.0,"publicationDate":"2002-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76309777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-03-01DOI: 10.1556/APH.16.2002.1-4.21
E. Smith
Hybrid mesons are produced when the gluonic degrees of freedom are excited within normal mesons. A large fraction of these gluonic excitations can be identified using unique combinations of spin, parity and charge conjugation (J PC ) quantum numbers which are not allowed for ordinary (qbar q) bound states. Photon beams are expected to be particularly favorable for the production of such states, which are required by the quark confining mechanism of QCD. Mapping out the spectrum and decay modes of these hybrid mesons is the necessary first step in understanding the nature of confinement. Plans are underway at Jefferson Lab to upgrade the energy of the electron accelerator to 12 GeV. With 12 GeV electrons, a 9 GeV linearly polarized photon beam will be produced using the coherent bremsstrahlung technique. Along with this energy upgrade, a hermetic detector housed in new experimental hall (Hall D) will be used to collect data on photoproduced mesons with unprecedented statistics.
{"title":"Searching for gluonic excitations —The Hall D project at Jlab","authors":"E. Smith","doi":"10.1556/APH.16.2002.1-4.21","DOIUrl":"https://doi.org/10.1556/APH.16.2002.1-4.21","url":null,"abstract":"Hybrid mesons are produced when the gluonic degrees of freedom are excited within normal mesons. A large fraction of these gluonic excitations can be identified using unique combinations of spin, parity and charge conjugation (J PC ) quantum numbers which are not allowed for ordinary (qbar q) bound states. Photon beams are expected to be particularly favorable for the production of such states, which are required by the quark confining mechanism of QCD. Mapping out the spectrum and decay modes of these hybrid mesons is the necessary first step in understanding the nature of confinement. Plans are underway at Jefferson Lab to upgrade the energy of the electron accelerator to 12 GeV. With 12 GeV electrons, a 9 GeV linearly polarized photon beam will be produced using the coherent bremsstrahlung technique. Along with this energy upgrade, a hermetic detector housed in new experimental hall (Hall D) will be used to collect data on photoproduced mesons with unprecedented statistics.","PeriodicalId":7004,"journal":{"name":"Acta Physica Hungarica","volume":"95 1","pages":"187-192"},"PeriodicalIF":0.0,"publicationDate":"2002-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85376139","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-03-01DOI: 10.1556/APH.16.2002.1-4.6
M. Ichimura, K. Kawahigashi
We report an evidence for the precursor phenomena of the pion condensation, which is found in the enhancement of the spin longitudinal cross sections ID q of the quasielastic 12C, (^{40} Ca(vec p, vec n)), reactions at the incident energy 494 and 346 MeV around the momentum transfer q ≈ q c , the critical momentum of the pion condensation. We utilized the distorted wave impulse approximation incorporated with the continuum random phase approximation. We adjusted the Landau-Migdal parameters, g′ NN and g′ NΔ, and obtained g′ NN ≈ 0.6–0.7 and g′ N Δ ≈ 0.3–0.4, which are consistent with those obtained from the energy of the Gamov-Teller giant resonance and the quenching factor of the Gamov-Teller sum rule.
{"title":"Enhancement of pionic modes in the quasielastic region","authors":"M. Ichimura, K. Kawahigashi","doi":"10.1556/APH.16.2002.1-4.6","DOIUrl":"https://doi.org/10.1556/APH.16.2002.1-4.6","url":null,"abstract":"We report an evidence for the precursor phenomena of the pion condensation, which is found in the enhancement of the spin longitudinal cross sections ID q of the quasielastic 12C, (^{40} Ca(vec p, vec n)), reactions at the incident energy 494 and 346 MeV around the momentum transfer q ≈ q c , the critical momentum of the pion condensation. We utilized the distorted wave impulse approximation incorporated with the continuum random phase approximation. We adjusted the Landau-Migdal parameters, g′ NN and g′ NΔ, and obtained g′ NN ≈ 0.6–0.7 and g′ N Δ ≈ 0.3–0.4, which are consistent with those obtained from the energy of the Gamov-Teller giant resonance and the quenching factor of the Gamov-Teller sum rule.","PeriodicalId":7004,"journal":{"name":"Acta Physica Hungarica","volume":"64 1","pages":"45-52"},"PeriodicalIF":0.0,"publicationDate":"2002-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87777790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-01-01DOI: 10.1556/APH.15.2002.1-2.4
I. Angeli
An empirical relation is established between Barrett equivalent radii Rk,α and rms charge radii 1/2 based on the results of model-independent and Fermi model analyses of 2p → 1s transitions in muonic atoms. This relation follows simple Z dependence, and can be usefully applied to derive rms radii 1/2 or differences δAA′ 1/2 in cases where only Rk,α data or isotope shifts δAA′ Rk,α are published. The atomic number dependence of the Barrett parameters k(Z) and α(Z) is also given by empirical formulae. It is shown that the Barrett moment can be expanded in a sum of integer moments (m ≥ 2) using an effective exponential parameter αeff(Z). The moments and isotopic differences δ of the two-parameter Fermi distribution expressed in terms of the parameters c and a are given in the Appendix for m = 1 – 10.
{"title":"Barrett moments and rms charge radii","authors":"I. Angeli","doi":"10.1556/APH.15.2002.1-2.4","DOIUrl":"https://doi.org/10.1556/APH.15.2002.1-2.4","url":null,"abstract":"An empirical relation is established between Barrett equivalent radii Rk,α and rms charge radii 1/2 based on the results of model-independent and Fermi model analyses of 2p → 1s transitions in muonic atoms. This relation follows simple Z dependence, and can be usefully applied to derive rms radii 1/2 or differences δAA′ 1/2 in cases where only Rk,α data or isotope shifts δAA′ Rk,α are published. The atomic number dependence of the Barrett parameters k(Z) and α(Z) is also given by empirical formulae. It is shown that the Barrett moment can be expanded in a sum of integer moments (m ≥ 2) using an effective exponential parameter αeff(Z). The moments and isotopic differences δ of the two-parameter Fermi distribution expressed in terms of the parameters c and a are given in the Appendix for m = 1 – 10.","PeriodicalId":7004,"journal":{"name":"Acta Physica Hungarica","volume":"94 1","pages":"87-102"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76434906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-01-01DOI: 10.1556/APH.15.2002.1-2.8
A. El-Naghy, M. Mohery, K. Gad
A statistical bond-percolation model for the fragmentation has been applied to the proton-induced reactions assuming a lattice structure to the prefragment nucleus and using the Monte Carlo technique to determine the bond to be broken. The model succeeded to reproduce the essential features of the mass yield curves for the p-Cu reaction at 3.9 GeV and to describe qualitatively the charge and the multiplicity distributions of the projectile fragments for the 28Si interactions with the quasi-free emulsion nucleon at 3.7 AGeV.
{"title":"The percolation mechanism for fragmentation of nuclei using Monte Carlo technique","authors":"A. El-Naghy, M. Mohery, K. Gad","doi":"10.1556/APH.15.2002.1-2.8","DOIUrl":"https://doi.org/10.1556/APH.15.2002.1-2.8","url":null,"abstract":"A statistical bond-percolation model for the fragmentation has been applied to the proton-induced reactions assuming a lattice structure to the prefragment nucleus and using the Monte Carlo technique to determine the bond to be broken. The model succeeded to reproduce the essential features of the mass yield curves for the p-Cu reaction at 3.9 GeV and to describe qualitatively the charge and the multiplicity distributions of the projectile fragments for the 28Si interactions with the quasi-free emulsion nucleon at 3.7 AGeV.","PeriodicalId":7004,"journal":{"name":"Acta Physica Hungarica","volume":"13 6","pages":"155-171"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72576915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-01-01DOI: 10.1556/APH.15.2002.1-2.6
W. Nörenberg, E. Nikonov, Y. Ivanov
The collective motion of nucleons from high-energy heavy-ion collisions is analyzed within a relativistic two-fluid model for different equations of state (EoS). As function of beam energy the theoretical slope parameter F y of the differential directed flow is in good agreement with experimental data, when calculated for the QCD-consistent EoS described by the statistical mixed-phase model. Within this model, which takes the deconfinement phase transition into account, the excitation function of the directed flow (P x ) turns out to be a smooth function in the whole range from SIS till SPS energies. This function is close to that for pure hadronic EoS and exhibits no minimum predicted earlier for a two-phase bag-model EoS. Attention is also called to a possible formation of nucleon antiflow (F y < 0) at energies ≳ 100 A·GeV.
{"title":"Directed flow of baryons from high-energy heavy-ion collisions","authors":"W. Nörenberg, E. Nikonov, Y. Ivanov","doi":"10.1556/APH.15.2002.1-2.6","DOIUrl":"https://doi.org/10.1556/APH.15.2002.1-2.6","url":null,"abstract":"The collective motion of nucleons from high-energy heavy-ion collisions is analyzed within a relativistic two-fluid model for different equations of state (EoS). As function of beam energy the theoretical slope parameter F y of the differential directed flow is in good agreement with experimental data, when calculated for the QCD-consistent EoS described by the statistical mixed-phase model. Within this model, which takes the deconfinement phase transition into account, the excitation function of the directed flow (P x ) turns out to be a smooth function in the whole range from SIS till SPS energies. This function is close to that for pure hadronic EoS and exhibits no minimum predicted earlier for a two-phase bag-model EoS. Attention is also called to a possible formation of nucleon antiflow (F y < 0) at energies ≳ 100 A·GeV.","PeriodicalId":7004,"journal":{"name":"Acta Physica Hungarica","volume":"48 1","pages":"117-130"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86127993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-08-01DOI: 10.1556/APH.15.2002.1-2.7
A. E. Naghy, S. Abdel-Aziz, S. Abou-Steit
The characteristics of the nucleus-nucleus collisions at high energy for the interactions of 1H, 4He, 12C, 16O, 22Ne, 28Si and 32S with emulsion at momentum (4.1 – 4.5) AGeV/c have been investigated. It has been found that the multiplicity distributions of the different emitted particles and their average values can be described by the modified cascade evaporation model. The model reproduces satisfactorily the multiplicity distributions of the shower, grey and black particles and the correlations between their multiplicities. It has been seen that the number of the produced shower particles increases with the increase of the projectile mass number. From the correlation between the average multiplicity of the evaporation particles and the number of the produced particles, it was found that a phase transition in the target system may occur. The calculated pseudo-rapidity distributions of the produced shower particles are typically Gaussian shaped in the mid-rapidity region and agree well with the experimental data. Also, the angular distributions of the grey and black particles have been investigated. The angular distributions of the grey particles show a universal shape independent of the type of projectile. The angular distributions of the black particles are nearly isotropic with a small asymmetry in the forward direction. The modified cascade evaporation model, reproduces the general characteristics of the nucleus-nucleus interactions and gives an explanation for the multiparticle production process.
{"title":"Comparative study for nucleus-nucleus interactions and modified cascade evaporation model at (4.1 – 4.5) AGeV/c","authors":"A. E. Naghy, S. Abdel-Aziz, S. Abou-Steit","doi":"10.1556/APH.15.2002.1-2.7","DOIUrl":"https://doi.org/10.1556/APH.15.2002.1-2.7","url":null,"abstract":"The characteristics of the nucleus-nucleus collisions at high energy for the interactions of 1H, 4He, 12C, 16O, 22Ne, 28Si and 32S with emulsion at momentum (4.1 – 4.5) AGeV/c have been investigated. It has been found that the multiplicity distributions of the different emitted particles and their average values can be described by the modified cascade evaporation model. The model reproduces satisfactorily the multiplicity distributions of the shower, grey and black particles and the correlations between their multiplicities. It has been seen that the number of the produced shower particles increases with the increase of the projectile mass number. From the correlation between the average multiplicity of the evaporation particles and the number of the produced particles, it was found that a phase transition in the target system may occur. The calculated pseudo-rapidity distributions of the produced shower particles are typically Gaussian shaped in the mid-rapidity region and agree well with the experimental data. Also, the angular distributions of the grey and black particles have been investigated. The angular distributions of the grey particles show a universal shape independent of the type of projectile. The angular distributions of the black particles are nearly isotropic with a small asymmetry in the forward direction. The modified cascade evaporation model, reproduces the general characteristics of the nucleus-nucleus interactions and gives an explanation for the multiparticle production process.","PeriodicalId":7004,"journal":{"name":"Acta Physica Hungarica","volume":"94 1","pages":"131-153"},"PeriodicalIF":0.0,"publicationDate":"2001-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90335066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2001-07-12DOI: 10.1556/APH.15.2002.3-4.21
M. Gai
GeV beams of light ions and electrons are used for creating a high flux of real and virtual photons, with which some problems in Nuclear Astrophysics are studied. GeV 8B beams are used to study the Coulomb dissociation of 8B and thus the 7Be(p,γ)8B reaction. This reaction is one of the major source of uncertainties in estimating the 8B solar neutrino flux and a critical input for calculating the 8B solar neutrino flux. The Coulomb dissociation of 8B appears to provide a viable method for measuring the 7Be(p,γ)8B reaction rate, with a weighted average of the RIKEN1, RIKEN2, GSI1 and MSU published results of S 17(0)=18.9±1.0 eV-b. This result, however, does not include a theoretical error estimated to be ±10%. GeV electron beams on the other hand, are used to create a high flux of real and virtual photons at TUNL-HIGS and MIT-Bates, respectively, and we discuss two new proposals to study the 12C(α,γ)16O reaction with real and virtual photons. The 12C(α,γ)16O reaction is essential for understanding Type II and Type Ia supernova. It is concluded that virtual and real photons produced by GeV light ions and electron beams are useful for studying some problems in Nuclear Astrophysics.
{"title":"KeV astrophysics with GeV beams; blazing a new trail on the summit of Nuclear Astrophysics","authors":"M. Gai","doi":"10.1556/APH.15.2002.3-4.21","DOIUrl":"https://doi.org/10.1556/APH.15.2002.3-4.21","url":null,"abstract":"GeV beams of light ions and electrons are used for creating a high flux of real and virtual photons, with which some problems in Nuclear Astrophysics are studied. GeV 8B beams are used to study the Coulomb dissociation of 8B and thus the 7Be(p,γ)8B reaction. This reaction is one of the major source of uncertainties in estimating the 8B solar neutrino flux and a critical input for calculating the 8B solar neutrino flux. The Coulomb dissociation of 8B appears to provide a viable method for measuring the 7Be(p,γ)8B reaction rate, with a weighted average of the RIKEN1, RIKEN2, GSI1 and MSU published results of S 17(0)=18.9±1.0 eV-b. This result, however, does not include a theoretical error estimated to be ±10%. GeV electron beams on the other hand, are used to create a high flux of real and virtual photons at TUNL-HIGS and MIT-Bates, respectively, and we discuss two new proposals to study the 12C(α,γ)16O reaction with real and virtual photons. The 12C(α,γ)16O reaction is essential for understanding Type II and Type Ia supernova. It is concluded that virtual and real photons produced by GeV light ions and electron beams are useful for studying some problems in Nuclear Astrophysics.","PeriodicalId":7004,"journal":{"name":"Acta Physica Hungarica","volume":"3 1","pages":"391-400"},"PeriodicalIF":0.0,"publicationDate":"2001-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89219020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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