共查询到20条相似文献,搜索用时 187 毫秒
1.
S. de Barros S. D. de Magalhães H. Wolf J. Barreto J. Eichler N. Lisbona I. O. de Souza D. M. Vianna 《Zeitschrift für Physik A Hadrons and Nuclei》1986,323(1):101-104
The excitation function for the fission isomer240mPu produced in the reaction of238U with α particles, has been measured at laboratory incident energies ranging from 20.1 to 27.3 MeV. A value of 3.8 ?0.4 +0.6 ns was obtained for the half-life of240mPu. The results are compared with other measurements performed using different experimental methods. 相似文献
2.
GAO CHUNG-SHOU 《中国物理C(英文版)》1979,3(4):518-522
In this note we propose that the electromagnetic self energy of lepton may beconnected with quantum number n by( (δm)/m)=(1/(2π))n-b ,in which b is a constant.Wefnrther propose that the cut-off value of momentum M is connected with gravitationalconstant κ and fine structure constant α by M=(1/√κ)αe-1-b.So we obtainthe mass formula of charged leptons M=(1/√κ)α exp{-3/4-b-(1/3α)n-b}.By using the masses of e- and μ- and the value of a as in put,we get the calculatedvalues of κ=(6.67231±0.00026)×10-8cm3g-1sec-2and mr=(1782.306±0.078)MeVwhich agree very well with experimental values κ=(6.6720±0.0041)×10-8cm3g-1sec-2 and mτ=(1782-4+3)MeV respectively.The mass of the fourth charged leptonpredicted by the formula should be m=(11725.47±0.51)MeV,which can be checkedby experiments in the near future.We also discuss briefly the proposed formula andthe obtained results. 相似文献
3.
Excitation curves for the reaction 27Al(n,α)24Na,46Ti(n,p)46Sc,48Ti(n,p)48Sc,51V(n,α)48Sc and 127I(n,2n)126I have been measured by the activation method in the4.5—18.3 MeV energy region.The cross section for the reactio 27Al(n,α)24Na was determined at 14.61±0.20 MeV.The measurement of neutron flux was performed using the associated particle method.The cross sections for other reactions were de-termined relative to the measured 27Al(n,α)24Na cross section.The resulting activities were measured employing a calibrated NaI(TI)scintillation counter.The values obtained were 117.5±3.0 mb,291.4±14.0mb,63.7±3.2 mb,16.8±0.9mb and 1656±68 mb respectively.A brief comparison with existing data was made. 相似文献
4.
FENG XiChen GUO YingXiang ZHOU XiaoHong LEI XiangGuo HUANG WenXue HE JianJun ZHU ShaoFei LIU Zhong ZHANG YuHu LUO YiXiao WEN ShuXian YUAN GuanJun WU XiaoGua 《中国物理C(英文版)》2000,24(4):359-363
The high-spin states of 206At have been studied in the 197An (12C, 3n)206At reaction at 12C energies from 60 to 80 MeV using technique of in-beam γ-ray spectroscopy. Measurements of Tray excitation functions, γ-γ-t coincidences, and y-ray angular distributions were performed. A level scheme for 206At, including a 10- isomer with a measured half-life of 908±400 ns, was established for the first the. The characteristics of the 10- isomers in doubly edd 206At nuclei were stressed. 相似文献
5.
A subnanosecond fission isomer has been found in 238Pu by means of a new fission-inflight technique. An isomer with a longer half-life reported previously in the same nucleus has been detected simultaneously. The half-lives are 0.5 ± 0.2 ns and 5 ± 2 ns respectively. Excitation functions show that the two isomers are separated by 1.3 ± 0.3 MeV, the short-lived isomer having the lowest excitation energy. It is assigned as the ground state while the 5 ns state is interpreted as a quasiparticle state in the second potential well. The difference of 1.3 MeV in excitation energy defines within the uncertainty the neutron energy gap at the isomeric deformation. 相似文献
6.
BES Collaboration 《中国物理C(英文版)》1996,20(2):97-106
Two processes ψ(2S)→π+π-J/ψ,J/ψ→1+1- and J/ψ→anything are carefully studied to get the J/ψ leptonic branching fractions with the ψ(2S)data at BES/BEPC.The results are B(J/ψ→e+e-)=(5.90±0.07±0.16)% and B(J/ψ→μ+μ-)=(5.96 ±0.08±0.16)%,and Be/Bμ is estimated to be 0.990±0.018±0.024.Assuming Be=Bμ,the leptonic branching fraction of the J/ψ is B(J/ψ→1+1-)=(5.93±0.05 ± 0. 16 )%.This result is used to estimate the QCD scale factor ∧(nf/MS) and the strong coupling constant αs. 相似文献
7.
A SENSITIVE METHOD TO DISTINGUISH THE SPIN OF THE HEAVY LEPTON τ FROM ITS TWO BODY DECAY ENERGY SPECTRA 下载免费PDF全文
We point out that in e++e-→τ++τ- for spin 3/2 τ±the different helicity statesof τ±will possess different weights.When the beam energy is much larger than themass of τ,we argue that,in some renormalizable models,τ may even have only ±1/2 helieity states.Therefore,the two body d cay energy spectra will show a significantdifference from that of τ with spin 1/2.This provides us with a very sensitivemethod to distinguish the spin of τ. 相似文献
8.
During the bombardment of 14.8MeV neutron on natural wolfram samples a γ-ray with energy 291.7keV and halflife 5.17±0.03 sec is observed. From the experimental facts it is assumed that in addition to the two well known transition branches from the decay of 5.2 sec isomer in 138W there exists another 11/2+11/2[615]→5/2-3/2[512] isomeric (E3) transition. The hindrance factor of this new transition is calculated. It is well cosistent with the general empirical rule of k- forbidden isomeric transition. 相似文献
9.
CHENG YE-HAO GONG KUN ZHU GUANG-HUA YANG JIN-GANG DING XUN-LIANG CHEN RUI-GUANG JIANG CHENG-LIE 《中国物理C(英文版)》1979,3(5):624-638
The excitation functions of the 23Na(p,α0)20Neg·s.and the 23Na(p,α1)20Nelst reae-tion have been measured from Ep=1 to 2.5 MeV at θL=30°,150° and 30°,respectively.Around the resonance at 2.171 MeV,the excitation functions of the(p,α0)reactionhave been measured at 12 angles,then,some angular distributions have been obtained from these excitation functions.In addition,the angular distribution of the(p,α0)reaction for the resonance at 2.171 MeV has also been measured directly at energy ofthe resonance peak of the excitation function at 150°.For the resonance at 2.117MeV,the angular distribution have been measured at two energies,one at the energyof the resonance peak of the excitation function at 150°,another at the energy of thehalf maximum point of the resonance peak on the higher energy side.Around the re-sonance at 2.075 MeV,the excitation functions have been measured at 16 angles,andthe angular distribution has been obtained from three excitation functions.The an-gular distributions of the three resonances are not symmetric about 90°,and the posi-tions of the resonance peaks of these resonances varies with the angle of measurement.By means of the compound nucleus theory,discussions have been made for these non-solated resonances. 相似文献
10.
et al 《中国物理C(英文版)》2010,34(6):831-835
We present a study of the inclusive photon spectra from 5.9 million J/ψ decays collected with the KEDR detector at the VEPP-4M e+e- collider. We measure the branching fraction of radiative decay J/ψ→ηcγ, ηc width and mass. Our preliminary results are: M(ηc)=2979.4±1.5±1.9 MeV/c2, Γ(ηc) = 27.8±5.1±3.3 MeV, B(J/ψ→ηcγ)=(2.34±0.15±0.40)%.
相似文献11.
The cross section measurement for the reaction 56Fe(n, p)56Mn was made using the activation method from 12 MeV to 18 MeV. The absolute cross section was determined at 14.61±0.20 MeV, the value obtained was 108.0±2.7mb. The associated particle method was used to determine the absolute neutron flux and compared with the recoil proton telescope. The agreement between both methods appeared to be within 1—2%. The resulting 56Mn activity was measured by using a φ10×7.6cm NaI (Tl) scintillation counter. The counting efficiency of the counter was achieved by means of a standard 56Mn source calibrated by the 4πβ-γ coincidence method. The result measured was compared with existing data. 相似文献
12.
A search for γ-rays preceding isomeric fission in the reaction238U(α, 2n)240mPu yielded negative results. Upper limits are given for the number of unconverted photons per isomer formed. 相似文献
13.
XIE QU-BING 《中国物理C(英文版)》1979,3(5):530-540
By assuming that in a high energy hadronic collision process,N pairs of stratonsare produced together with gluons,the number of which is supposed to be propor-tional to the number of“bonds”between any two stratons,we are able to get a rela-tion between the Q-value and the number of pairs N:N=(α2+βQ)1/2-α.The average charged multiplicity〈nch〉theo is calculated,and is compared withthe experiments.The data of pp、π±p、K±p collisions all coincide with the theoreticalcurve in a wide range of energies.The deviation between the energy vs.chargedmultiplicity relations for meson-proton and proton-proton collision processes are ex-plained quantitatively.The average straton mass estimated from the theory is ingood agreement with that.given by other authors. 相似文献
14.
The B (M1) value of the l-forbidden M1 transition of 40Ca ±1 nuclei were calculatedwith the effective g-factors in 40Ca region. The results give a explanation of strong l-forbidden M1 transitions of 39K, 41K. A qualitative explanation for the reason of largedifference of B(M1) value of l-forbidden M1 transition between 39K, 41K and 39Ca, 41Cais given also. 相似文献
15.
The Technicolor(TC)O(αmt2/mw2)corrections to top pair production in high energy e+e- annihilation are calculated in the one generation TC model.The analytic expressions are given for the form factor, the renormalized matrix element and its square.Numerical examples are presented for the corrections to the total cross-section ,the forward-backward asymmetry AFB and the left-right asymmetry ALR.We found that the corrections can reach -12.3%, -3.3% and -11.7% to the observables,AFB and ALR respectively for the favorable parameter values.The level of these corrections might be achieved at the next-generation linear collider(NLC).It might open a window for testing TC theory. 相似文献
16.
THE VERTICAL INTEGRATED MOMENTUM SPECTRUM OF THE MUON WITH MOMENTUM LARGER THAN 4 GeV/c AT 3220m ABOVE SEA-LEVEL 下载免费PDF全文
JING GUI-RU HUO AN-XIANG YAN YU-KUI WANG LI-AN LI YAN-GUO SU DENG-JI MENG XIANG-CHENG YAO WEI-ZHONG ZHOU YIN-ZAO PENG SHAO-HUA WANG LI-HUI 《中国物理C(英文版)》1978,2(5):417-422
At an altitude of 3220 meters above sea level in Yunnan Province, we measured, by using a G-M counter-magnetic spectrometer, the vertical integratted momentum spectrum of the cosmic muon with momentum larger than 4 GeV/c. The spectrum obtained from this experiment is expressed by a power function in the form of I(>p)=Q (p+4)-1.86±0.06(cm-2·sr-1·s-1), where p is in GeV/c and Q is a constant. We also measured the charge ratio of muon in the 4—23 GeV/c momentum range. The result is Nμ/Nμ-=1.26±0.11. The error in the momentum measurement with spectrometer has been discussed and calculated. 相似文献
17.
THE MEASUREMENT OF THE EXCITATION FUNCTIONS OF ISOTOPES OF Fr AND At,PRODUCED IN THE BOMBARDMENT OF 12C ON 209Bi 下载免费PDF全文
Excitation functions for Fr and At isotopes produced in 12C on 209Bi had been measured in the energy range 60—72 MeV. It was quite obvious that 213Fr and 214Fr were formed by the reactions 209Bi (12C,4n) 217Ac and 209Bi (12C,3n) 218Ac following the a decay of the Ac isotopes respectively, and 214mFr was produced probably by compound nucleus evaporation of neutrons and an α particle, i.e. (12C, α 3n). 211At was mainly contributed by a multi-nucleon transfer reaction (e.g. 8Be transfer). The experimental data for neutron evaporation reaction were fitted by the Jackson formula. 相似文献
18.
The Cross Section Fluctuation of the Isotope Projectile-Like Fragments in the Dissipative Process of Reaction 19F+51V 下载免费PDF全文
Wang Qi Lu Jun Xu Hushan Li Songlin Zhu Yongtai Yin Xu Fan Enjie Zhang Yuhu Li Zhichang Zhao Kui Lu Xiuqin Hu Xiaoqing 《中国物理C(英文版)》1996,20(4):289-296
By using a detection system combining Time-of-Flight(TOF)method with(△E-E)technique,the excitation functions,the dependence of energy coherence widthΓon product mass A and the dependence of Γon the degree of freedom of neutron excess N/Z for some elements and their isotope products in the dissipative process of reaction 19F+51V at energies from 102.25MeV to 109.50 MeV(in 250 keV steps)were presented and discussed for the first time. 相似文献
19.
In this paper a unified electro-weak model for leptons based on the SU(3) gaugegroup is suggested by means of four kinds of realization for the generators of thegroup. For all low energy electro-weak processes, this model predicts the same resultsas the conventional Weinberg-Salam model does. The Weinberg angle is shown to be sin2θw=1/4 in a natural way. When the Higgs self potential respects a discrete symme-try Φ→-Φ, a new conserved quantum number called weak strangeness emerges fromthe model after spontaneous symmetry breaking. In the present model there existanother four heavy vector gauge bosons V± and U±± together with some heavyfermions and Higgs scalars, which have non vanishing weak strangeness quantumnumbers. These weak strange particles have no direct couplings with leptons. Theirexistence will not influence the low energy electro-weak processes. Nevertheless, theycan be produced in pairs in high energy collisions and the lightest of them should bestable if the conservation of weak strangeness is exact. The experimental implicationsand the possibility of violation of the conservation of weak strangeness are also dis-cussed. 相似文献
20.
YU SHOU-MIEN 《中国物理C(英文版)》1982,6(1):36-43
A relativistic equation of motion of a two particle system under the constraints pi2-mi2-U(x2)=0.(i=1,2), where U(x2) is an infinite spherical square well poten-tial, is applied to the SU(4) quark model of mesons. A set of linear mass relations areobtained. Instead of the linear relation between J and M2, the Regge trajectory ob-tained is a relation between pnl2 and M2, where ζnlπ are zeros of the spherical Besselfunctions. The new trajectory seems more satisfactory than the former one. 相似文献