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对60AGeV^16O诱发乳胶核反应射弹α碎片的发射进行了研究,得到α射弹碎片多重数分布服从KNO标度无关性。在边缘作用下,α射弹碎片的产生与靶核碎片的产生存在线性关联,靶核碎片平均多重数随α射弹碎片数的增加线性减小,它可以很好地利用核作用几何模型来解释。 相似文献
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对60 A GeV16O在原子核乳胶中的电磁离解现象首次进行了高统计的研究,得到电磁离解截面随束流能量的增加而增加,射弹碎片电荷分布和200 A GeV16O在乳胶中电磁离解的电荷分布一致,但电荷为3≤Z≤5的射弹碎片的发射概率低于200 A GeV能区,这些特点和Weiszacker和Williams的经典电磁理论模型计算结果一致.60 A GeV16O电磁离解下各反应道出现的概率和200 A GeV能区结果基本一致,但同14.6 A GeV能区的结果不同,在60 A GeV能区16O电磁离解主要是由电偶及电四激发引起的巨偶极和巨四极共振及准氘核效应过程所致,这一点可以通过电磁离解下质子的多重数分布得到定性解释.电磁离解下α射弹碎片的分布同非弹核作用下α碎片的分布规律不同,说明α碎片的产生机制不同. 相似文献
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对60 A GeV16O在原子核乳胶中的电磁离解现象首次进行了高统计的研究,得到电磁离解截面随束流能量的增加而增加,射弹碎片电荷分布和200 A GeV16O在 乳胶中电磁离解的电荷分布一致,但电荷为3≤Z≤5的射弹碎片的发射概率低于200 A GeV能 区,这些特点和Weiszacker和Williams的经典电磁理论模型计算结果一致.60 A GeV16 O电磁离解下各反应道出现的概率和200 A GeV能区结果基本一致,但同14.6
关键词:
电磁离解
射弹碎片
碎裂 相似文献
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报道30MeV/u40Ar+159Tb反应中碎片碎片关联函数的实验结果.利用三体弹道模型从关联函数提取了中等质量碎片发射时间.中等质量碎片的平均发射时间随碎片能量而变化,从低能时的约500fm/c下降至高能时的约100fm/c.中等质量碎片发射时间随束流能量的升高而下降,表明随着束流能量的升高中等质量碎片发射机制逐渐从相继两体衰变向多重碎裂发射过渡.对于40Ar+159Tb反应,此过渡能区在35—45MeV/u之间 相似文献
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We present in analytic form the O(alphas5) correction to the H-->gg partial width of the standard-model Higgs boson with an intermediate mass MH<2Mt. Its knowledge is useful because the O(alphas4) correction is sizable (around 20%). For MH=120 GeV, the resulting QCD correction factor reads 1+(215/12)alphas(5)(MH)/pi+152.5[alphas(5)(MH)/pi]2+381.5[alphas(5)(MH)/pi]3 approximately 1+0.65+0.20+0.02. The new four-loop correction increases the total Higgs-boson hadronic width by a small amount of order 1 per thousand and stabilizes significantly the residual scale dependence. 相似文献
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Using recently developed methods for the evaluation of five-loop amplitudes in perturbative QCD, corrections of order alphas4 for the nonsinglet part of the cross section for electron-positron annihilation into hadrons and for the decay rates of the Z boson and the tau lepton into hadrons are evaluated. The new terms lead to a significant stabilization of the perturbative series, to a reduction of the theory uncertainly in the strong coupling constant alphas, as extracted from these measurements, and to a small shift of the central value, moving the two central values closer together. The agreement between two values of alphas measured at vastly different energies constitutes a striking test of asymptotic freedom. Combining the results from Z and tau decays we find alphas(MZ)=0.1198+/-0.0015 as one of the most precise and presently only result for the strong coupling constant in order alphas4. 相似文献
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We present in analytic form the matching conditions for the strong-coupling constant alphas(nf) (mu) at the flavor thresholds to four loops in the modified minimal-subtraction scheme. Taking into account the present knowledge on the coefficient beta4 of the Callan-Symanzik beta function of quantum chromodynamics, we thus derive a five-loop formula for alphas(nf) (mu) together with appropriate relationships between the asymptotic scale parameters Lamda(nf) for different numbers of flavors nf. 相似文献
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L. Krlín 《Czechoslovak Journal of Physics》1993,43(1):43-49
The paper brings analytical estimates of induced radial diffusion of alphas and ions, caused by their interaction with lower hybrid and fast waves. 相似文献
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The emission of projectile fragments alpha has been studied in 84Kr interactions with nuclei of the nuclear emulsion detector composition at relativistic energy below 2 GeV per nucleon. The
angular distribution of projectile fragments alpha in terms of transverse momentum could not be explained by a straight and
clean-cut collision geometry hypothesis of Participant — Spectator (PS) Model. Therefore, it is assumed that projectile fragments
alpha were produced from two separate sources that belong to the projectile spectator region differing drastically in their
temperatures. It has been clearly observed that the emission of projectile fragments alpha are from two different sources.
The contribution of projectile fragments alpha from contact layer or hot source is a few percent of the total emission of
projectile fragments alphas. Most of the projectile fragments alphas are emitted from the cold source. 相似文献
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R. Billerey C. Cerruti A. Chevarier N. Chevarier B. Cheynis A. Demeyer 《Zeitschrift für Physik A Hadrons and Nuclei》1979,292(3):293-299
Angular correlations between charged reaction products have been measured for the reaction14N+27A1 at 70 and 100 MeV. Light particle evaporation from the heavy recoil is shown to be the dominant process. In addition, however fast alphas are observed for all reaction channels. From the three-body kinematics we conclude that these alphas are emitted from the contact zone between the two heavy ions. A comparison of the results forE Lab=70 and 100 MeV excludes an explanation of this process by the recently suggested “Piston” or “hot-spot” models. 相似文献
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Detectors for recording alphas from fusions in D2–T2 gas targets require protection against diffusion of tritium into the detector medium. Tests have been carried out on surface barrier detectors to determine the feasibility of using thin coatings of oxide and metal for this purpose. The results show that a layer of 0.5 m aluminium oxide plus 0.2 m gold provides effective protection for at least 280 h, without impairing the transmission of 2 MeV alphas into the detector. Tests of an alternative detector, a phoswich of thin film plastic and lithium-glass scintillators, are also described. 相似文献
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G. M. Chernov 《Radiation measurements》1995,25(1-4):269-270
The search for and study of the coherent dissociation reaction 16O → 4 have been made at 4.5 GeV/c per nucleon in emulsion. The momentum and correlation characteristics of alphas cannot be described by the statistical model of prompt fragmentation. The decay “temperature” is considerably smaller than one for the usual multifragmentation of relativistic projectiles. 相似文献
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齐昌伟 《核聚变与等离子体物理》1993,13(2):62-64
在稳态托卡马克堆的燃烧阶段,当感应电流下降后,新经典输运产生的自举电流便成为维持稳定电流的最好手段。本文根据α粒子新经典自举电流的最新结果,计算了感应电流消失阶段,稳态堆中α粒子、电子和离子的自举电流。 相似文献
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T Madhusoodhanan Samit Mandal MP Sathyavathiamma Ramani NG Puttaswamy TS Mudhole A Mandal DK Avasthi R Shyam SK Datta 《Pramana》1999,53(3):541-544
The inclusive and exclusive measurements were carried out for 7Li projectile breakup on 27Al target at 48 MeV. In the inclusive data we have observed a broad peak around the beam velocity for alphas and tritons.
The exclusive data for alpha-triton coincidences show good agreement with the post-form DWBA theory of breakup reactions. 相似文献