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1.
In [V.E. Viola et al., Phys. Rev. Lett. 93 (2004) 132701, D.S. Bracken et al., Phys. Rev. C 69 (2004) 034612] the observed decrease in spectral peak energies of IMFs emitted from hot nuclei was interpreted in terms of a breakup density that decreased with increasing excitation energy. Subsequently, Raduta et al. [Ad. Raduta et al., Phys. Lett. B 623 (2005) 43] performed MMM simulations that showed decreasing spectral peaks could be obtained at constant density. In this Letter we point out that this apparent inconsistency is due to a selective comparison of theory and data that overlooks the evolution of the fragment multiplicities as a function of excitation energy. 相似文献
2.
Bearden IG Beavis D Besliu C Blyakhman Y Budick B Bøggild H Chasman C Christensen CH Christiansen P Cibor J Debbe R Enger E Gaardhøje JJ Hagel K Hansen O Holm A Holme AK Ito H Jakobsen E Jipa A Jørdre JI Jundt F Jørgensen CE Karabowicz R Keutgen T Kim EJ Kozik T Larsen TM Lee JH Lee YK Løvhøiden G Majka Z Makeev A McBreen B Mikelsen M Murray M Natowitz J Nielsen BS Norris J Olchanski K Olness J Ouerdane D Płaneta R Rami F Ristea C Röhrich D Samset BH Sandberg D Sanders SJ Sheetz RA Staszel P 《Physical review letters》2002,88(20):202301
We present charged-particle multiplicities as a function of pseudorapidity and collision centrality for the 197Au+197Au reaction at square root[s(NN)] = 200 GeV. For the 5% most central events we obtain dN(ch)/deta/(eta = 0) = 625+/-55 and N(ch)/(-4.7< or =eta < or =4.7) = 4630 +/- 370, i.e., 14% and 21% increases, respectively, relative to square root[s(NN)] = 130 GeV collisions. Charged-particle production per pair of participant nucleons is found to increase from peripheral to central collisions around midrapidity. These results constrain current models of particle production at the highest RHIC energy. 相似文献
3.
M.N. Namboodiri P. Gonthier H. Ho J.B. Natowitz R. Eggers L. Adler P. Kasiraj C. Cerruti A. Chevarier N. Chevarier A. Demeyer 《Nuclear Physics A》1981,367(2):313-332
The emission of H and He isotopes in the reactions of 120 MeV 20Ne with 27A1 has been studied using light particle-heavy ion coincidence measurements. The energy spectra and angular correlations of the light particles emitted in coincidence with products of agree well with the predictions of the statistical model applied to the decay of the compound nucleus 47V. Results on α-particle emission associated with deep inelastic reactions leading to carbon and oxygen products are also reported. 相似文献
4.
K.A. Geoffroy J.B. Natowitz R. Eggers P. Kasiraj M.N. Namboodiri 《Nuclear Physics A》1978,302(1):333-342
The emission of prompt γ-radiation in the de-excitation of the products of the reactions of 120 MeV 20Ne with 27Al has been studied. Three NaI detectors placed at angles of 35°, 90° and 145° to the direction of the 20Ne beam were used to detect γ-rays in coincidence with reaction products having 6 ≦ Z ≦ 20, detected in a counter telescope. Data were obtained with the counter telescope in the same plane, as well as in a plane perpendicular to the plane defined by the beam and the NaI detectors. The average multiplicities 〈Mγ〉, average energies 〈Eγ〉, primary γ-ray energy spectra and the variation of 〈Mγ〉 and 〈Eγ〉 with angle of observation and kinetic energy of the detected products are presented and discussed in terms of the dominant reaction mechanisms. 相似文献
5.
Breakup densities of hot 197Au-like residues have been deduced from the systematic trends of Coulomb parameters required to fit intermediate-mass-fragment kinetic-energy spectra. The results indicate emission from nuclei near normal nuclear density below an excitation energy E(*)/A less, similar 2 MeV, followed by a gradual decrease to a near-constant value of rho/rho(0) approximately 0.3 for E(*)/A greater, similar 5 MeV. Temperatures derived from these data with a density-dependent Fermi-gas model yield a nuclear caloric curve that is generally consistent with those derived from isotope ratios. 相似文献
6.
J. B. Natowitz S. Leray R. Lucas C. Ngô E. Tomasi C. Volant 《Zeitschrift für Physik A Hadrons and Nuclei》1986,325(4):467-474
A simple formula based on leading particle models of nucleon-nucleon collisions is used to evaluate the average momentum transfer in central heavy ion collisions at energies from 20 to 150 MeV/u. This formula, which reproduces a number of the features of the observed systematics, offers a straightforward explanation for the approximate universality of fractional linear momentum transfer as a function of velocity, the dependence of fractional momentum transfer on target mass and the greater fractional momentum transfer of the proton as compared to heavy ion projectiles. 相似文献
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8.
Bearden IG Beavis D Besliu C Blyakhman Y Budick B Bøggild H Chasman C Christensen CH Christiansen P Cibor J Debbe R Enger E Gaardhøje JJ Germinario M Hagel K Hansen O Holm A Holme AK Ito H Jakobsen E Jipa A Jundt F Jørdre JI Jørgensen CE Karabowicz R Keutgen T Kim EJ Kozik T Larsen TM Lee JH Lee YK Løvhøiden G Majka Z Makeev A McBreen B Mikelsen M Murray M Natowitz J Nielsen BS Norris J Olchanski K Olness J Ouerdane D Płaneta R Rami F Ristea C Röhrich D Samset BH Sandberg D Sanders SJ 《Physical review letters》2003,90(10):102301
We present ratios of the numbers of charged antihadrons to hadrons (pions, kaons, and protons) in Au+Au collisions at sqrt[s(NN)]=200 GeV as a function of rapidity in the range y=0-3. While the ratios at midrapidity are approaching unity, the K(-)/K(+) and p;/p ratios decrease significantly at forward rapidities. An interpretation of the results within the statistical model indicates a reduction of the baryon chemical potential from mu(B) approximately 130 MeV at y=3 to mu(B) approximately 25 MeV at y=0. 相似文献
9.
U. Milkau M. L. Begemann-Blaich E. -M. Eckert G. Imme P. Kreutz A. Kühmichel M. Lattuada U. Lynen C. Mazur W. F. J. Müller J. B. Natowitz C. Ngô J. Pochodzalla G. Raciti M. Ribrag H. Sann W. Trautmann R. Trockel 《Zeitschrift für Physik A Hadrons and Nuclei》1993,346(3):227-236
Inclusive cross sections of intermediate mass fragments from the reaction84Kr+197Au atE/A=35 MeV were measured over the range 8°≦Θ lab≦70° with a low detection threshold. A moving-source parameterization was used to fit the double-differential cross sections. The integrated cross section for fragment production exceeds the total reaction cross section thus indicating a large probability for multi-fragment processes. The deduced large temperature parameters can be explained by assuming emission from a rotating source. From the comparison to reactions with12C and40Ar projectiles at E/A=30 MeV a systematics of inclusive fragment production as a function of the projectile mass is obtained. 相似文献
10.
M. Berlanger B. Borderie D. Chapoulard C. Gerschel F. Hanappe J. Kuzminski J. Natowitz C. Ngô N. Perrin B. Tamain 《Nuclear Physics A》1982,388(1):187-204
For the Cu + Au 400 MeV system γ-ray multiplicities have been measured. The mean value of the transferred angular momentum, the variances, and the repartition of angular momentum between the fragments have been deduced. It is shown that, early in the reaction the building up of angular momentum is a very fast process. For longer times, additional angular momentum is induced in the fragments. The excitation of collective modes can account for this effect. The properties of such modes have been analysed. 相似文献