共查询到20条相似文献,搜索用时 31 毫秒
1.
The QCD effects are shown to result at in a considerable increase of the νN cross section and modification of in comparison with scaling. At the QCD cross section is twice that of scaling. At the QCD structure functions of the nucleon acquire effective scaling behaviour. 相似文献
2.
Analog (fp)3 states preferentially excited in the and the reactions have been identified in the mass 43 mirror nuclei. A simple zero-range DWBA calculation made with a cluster form factor gives good agreement with the measured angular distributions, but spectroscopic strengths deduced for mirror levels do not agree. The 3p-0h states are excited with a rather uniform cross section not strongly correlated with spins. 相似文献
3.
F. Plouin J. Duflo L. Goldzahl G. Bizard F. Bonthonneau M. Cottereau J.L. Laville C. Le Brun F. Lefebvres J.C. Malherbe R. Regimbart 《Nuclear Physics A》1978,302(2):413-422
A significant production of the ABC effect is observed in the free nucleon reaction n+p → d+(mm)°, using a 1.88 GeV/c neutron beam. The complete deuterón momentum spectra produced in this inclusive experiment are measured at 0°, 4.5°, 7.5° and 10.5° (lab). The double differential cross sections , are compared with the predictions of two exchange models. 相似文献
4.
Multistep transfer contributions in inelastic heavy ion scattering are investigated in a coupled channels model for the reaction . We find that only the interference of the one- and two-step transfer contributions gives agreement with recent experimental results. This is interpreted as strong evidence for multistep processes in heavy ion scattering. 相似文献
5.
The cross section, vector analyzing power, and proton polarization have been measured for the ln = 0 reaction 116Sn(d, p)117Sn(g.s.) at 8.22 MeV. In addition, cross section and analyzing power data have been obtained at 8.22 MeV for and for 116Sn(d, p)117Sn leading to excited states of 117Sn at 0.159, 0.317, 1.020, 1.179, 1.308 and 1.497 MeV. The cross section and analyzing power for and for leading to the 1.294 MeV state of 116Sn have also been measured at 12.91 MeV. The data for 116Sn(d, p)117Sn(g.s.) have been used to separate the contributions to the analyzing power arising from spin-dependent forces in the proton and deuteron channels. A similar analysis is presented for an transition at 11 MeV. Optical-model analyses have been performed for the elastic scattering data. The reaction data have been compared with distorted-wave calculations in order to investigate the validity of various deuteron potentials, as well as to extract spectroscopic information. 相似文献
6.
P. Gregory D. Everett P. Grossmann P. Mason H. Muirhead G. Warren R. Carlsson G. Ekspong S.O. Holmgren S. Nilsson R. Stenbacka C. Walck 《Nuclear Physics B》1974,78(2):222-232
Relations have been derived between the invariant cross sections for various inclusive processes by assuming factorisation of the leading (pomeron) and non-leading (meson) trajectories. In this paper predictions for the invariant cross sections have been tested using data from interactions at 4.6 and 9.1 GeV/c.A large discrepancy between experiment and theory is apparent for the π? data: in the π+ case the discrepancy is less marked but still present. 相似文献
7.
The total cross section for the production of a muon pair of invariant mass Q2via the Drell-Yan mechanism and the Feynman xF differential cross section are calculated in QCD retaining all terms up to order αs(Q2. The calculations are performed using dimensional regularisation of the intermediary infrared and collinear singularities, but we present our results in a form independent of such details. The corrections to both these cross sections coming from radiative corrections to the lowest-order annihilation diagram are found to be large at present values of Q2 and S when the cross section is expressed in terms of parton densities derived from leptonproduction, for all Drell-Yan processes of practical interest. Numerical calculations are presented which show, for any reasonable parametrisation of the parton densities, that the neglect of higher-order terms in αs(Q2) is not justifiable. The quark-gluon diagrams on the other hand give small corrections in this order and are only important for PP scattering. 相似文献
8.
Yu.M. Antipov V.A. Bessubov N.P. Budanov Yu.P. Gorin S.P. Denisov S.V. Klimenko A.A. Lebedev Yu.V. Mikhailov A.I. Petrukhin S.A. Polovnikov V.N. Roinishvili D.A. Stoyanova F.A. Yotch 《Physics letters. [Part B]》1978,76(2):235-236
The differential cross sections and of inclusive J/ψ production by 43 GeV/c π? off Be, Cu and W nuclei have been measured. Fitting we observed the increase of α with pt2. 相似文献
9.
Yu.M. Shabelsky 《Nuclear Physics B》1978,132(5):491-508
The process of the hadron-nucleus interaction is considered in the framework of Glauber theory. A two-channel model is used for inelastic shadow corrections due to low-mass diffractive jets. It is shown that inelastic hadron-nucleus cross sections are connected with the cuts of a number of hadron-nucleon blobs in the elastic scattering amplitude. The relations derived between contributions to the absorptive part of the amplitude from cuts of different kinds satisfy the Abramovsky-Gribov-Kancheli rules up to a factor which is determined by the ratio of the inelastic and total hadron-nucleon cross sections. The inclusive spectrum in the central region is proportional to . The average charged multiplicity increases with A slower than due to energy conservation. The results obtained are in good agreement with experimental data on the average multiplicities and distributions of charged particles. 相似文献
10.
Results are presented of a 12 event/μb bubble-chamber experiment; the reactions discussed in detail are .The K1 (890)?p channel is dominated by the forward peak. The suggestion of flattering at cos θ = 1 is more pronounced in ; which is mainly natural-parity exchange. Pseudoscalar exchange contributes to ; this is more sharply peaked in t. The value of is somewhat larger than the upper limit from the dominant natural-parity exchange. There is significant structure in .The K1 (1420)?p channel is much more pronounced at 3.3 GeV/c than at 3.13 GeV/c, but is not markedly peripheral. The width of the K1 (1420) in the 3.3 GeV/c data is 42 ± 12 MeV/c2.The cross section for agrees with that expected from , assuming a single t-channel exchange. Our measured density matrix elements are consistent with a strong pseudoscalar exchange. 相似文献
11.
K. Moriyasu T. Burnett D. Holmgren H.J. Lubatti D. Rees G. Swider B. Yuldashiev K. Dziunikowska A. Eskreys K. Eskreys A. Gula D. Kisielewska H. Rudnicka P. Stopa W. Ko R.L. Lander J.S. Pearson D. Pellett A. Zieminski 《Nuclear Physics B》1978,137(4):377-389
Double-scattering effects are studied in π?d interactions at 360 GeV/c. The partial cross sections are presented. The double-scattering probability per πd collision is found to be . We have extracted the partial cross section XN of the double-scattering plus interference contributions, and find that XN obeys KNO scaling. The data are compared with various theoretical predictions. 相似文献
12.
I.O. Kulik 《Physics letters. A》1984,106(4):187-190
For metals with small electron and phonon mean free paths (alloys, deformed or amorphous materials), there exists a possibility of determining α2F(ω) by measuring the V dependence of or of wide (d ? 103 Å) point contacts (PC) and then inverting the linear equation relating these quantities to α2F(ω). The procedure is elaborated numerically and tested successfully for model electron-phonon interaction spectra. 相似文献
13.
T. Fujii T. Kondo F. Takasaki S. Yamada S. Homma K. Huke S. Kato H. Okuno I. Endo H. Fujii 《Nuclear Physics B》1977,120(3):395-422
The differential cross sections for γp→π+n from hydrogen and the ratios from deuterium were measured at nine c.m. angles between 30° and 150° for laboratory photon energies between 260 and 800 MeV. A magnetic spectrometer with three layers of scintillation hodoscope was used to detect charged π mesons. The cross section for γn→π?p was obtained as a product of and the ratio. The overall features in the cross sections of the two reactions, γp→π+n and γn→π?p, and in the ratios, , agree with predictions by Moorhouse, Oberlack and Rosenfeld, and Metcalf and Walker. An investigation of the possible existence of an isotensor current was made and a negative result was found. In detailed balance comparison with the new results on the inverse reaction π?p→γn, no apparent violation of time-reversal invariance was observed. 相似文献
14.
Two procedures are described to predict the selectivity of heavy-ion (HI) compound reactions for excitation of high spins. The applicability of statistical-model calculations in respect to yrast line effects is discussed. Contour diagrams of the total cross sections are derived, yielding the gradient and the p to “background” ratio of high-spin states as well as the “optimum Q-value” for any given HI compound reaction. The dependence of both the optimum Q-value and the shape of on the critical L-value at high bombarding energies can be used to determine Lcrit. This is demonstrated for the reaction . A rougher estimate of the selectivity is given by the “grazing-collision picture” which is based on a consideration of the angular momentum balance. Using the reactions 10B(12C, d), 12C(12C, d), 12C(14N, d), 11B(14N, p), 13C(14N, p), and 12C(14N, 6Li) as examples, the theoretical predictions are shown to be in excellent agreement with experiment, for bombarding energies ranging between 40 and 120 MeV. The possibility to predict the high-spin selectivity is the precondition for an application of HI compound reactions for investigations of yrast lines and converts this class of reactions into an outstanding means for spectroscopy of high-spin states in light nuclei. 相似文献
15.
A. Voros 《Nuclear Physics B》1980,165(2):209-236
We investigate the levels of the quartic oscillator () by means of the associated zeta function. By using several versions of the semiclassical approach, we prove exact results concerning the locations of the real zeros and of the poles of that function, the residues of which are essentially the coefficients of the semiclassical expansion of the Bohr-Sommerfeld quantization rule. We also compute the derivative of the zeta function at the origin, by relating it to the Fredholm determinant of the operator. These results translate as sum rules for the eigenvalues and thus are helpful for their precise computation, and a further analysis allows one to split them into separate rules for even and odd levels; the extension to higher anharmonic oscillators () is immediate. Finally we propose an asymptotic formula for large negative arguments of the zeta function, based on the nature and location of the complex singularities of the partition function of the operator . 相似文献
16.
G.W. Brandenburg W.B. Johnson D.W.G.S. Leith J.S. Loos J.A.J. Matthews F.C. Winkelmann R.J. Yamartino 《Physics letters. [Part B]》1973,44(3):305-309
Differential cross sections for center of mass scattering angles near 90° are presented for the reactions , and KL°p → KS°p in the momentum interval 1.0 to 7.5 GeV/c. The energy dependences of these cross sections are found to be equally well described by the parameterization: or . 相似文献
17.
R.E. Warner D.C. Martin G.C. Ball W.G. Davies A.J. Ferguson D. Horn 《Nuclear Physics A》1979,326(1):209-224
We have searched for double spectator pole events in the reaction , such that the deuteron from the projectile goes forward with the beam velocity while α or d from the target remains at rest. Triple coincidence studies of the reaction show such events, but with the 0° deuteron energy spectrum peaked at slightly higher velocities. Similar effects are seen in d-6Li double coincidence spectra from the single breakup reaction . Quasi-free inelastic scattering, where the d from the projectile receives no momentum transfer while the α excites the target to its first excited state, is also shown to be an important mechanism. 相似文献
18.
19.
K.M. Hartmann 《Nuclear Physics A》1978,305(1):279-292
The energy spectra and angular distributions observed in deep inelastic collisions (DIC) between heavy ions are usually ascribed to statistical fluctuations caused by the large excitation energies involved. We give arguments that fluctuations due to qiiantal effects may also be important and derive an expression for the double differential cross section (θ is the scattering angle, Q the energy loss) which contains only these latter fluctuations. The typical features observed are reproduced by the theory which, apart from an overall normalization factor, contains just one parameter. 相似文献
20.
H.G. Kirk R. Schulte P. Sixel M. Klein M. Walter M.J. Counihan D.J. Kocher P. Kostka P.K. Malhotra D.R.O. Morrison H. Saarikko K.L. Wernhard K.W.J. Barnham R.M. Eason D.P. Dallman F. Mandl M. Markytan 《Nuclear Physics B》1976,116(1):99-117
The inclusive production of K?1(890) and K?1(1420) is studied in K??p interactions at 10 and 16 GeV/c. At 10 GeV/c an enhancement in the () mass distribution is found at 1.74 GeV, but no clear signal is seen at 16 GeV/c. The fraction of coming from decay of the is large, being (50 ± 6)% and (45 ± 5)% at 10 and 16 GeV/c, respectively. The inclusive cross sections for K1?(890) and production are almost constant with energy from 8 to 32 GeV/c with values of 3.5 and 3.3 mb, respectively. The production cross section is studied as a function of transverse and longitudinal variables and found to derive mainly from fragmentation of the incident K? meson. The spectra of resulting from the decay of are studied. 相似文献