共查询到20条相似文献,搜索用时 31 毫秒
1.
The axial anomaly is discussed from various points of view. Two consistent theories for a field interacting with gravity are considered: supergravity and a real quantized field in a classical gravitational background. The Feynman graph method, the zeta function regularization method, the point splitting method and the topological method all yield the same result for the latter theory, in agreement with that first found by Christensen and Duff. 相似文献
2.
We point out a limiting procedure which enables one to construct in supergravity theories non-gauge, linearized spin- fields with the aid of the supercovariantly constant spinors. We give an explicit application of the procedure for N = 2 supergravity. 相似文献
3.
P. Bosetti M. Deutschmann H. Grässler G. Otter H.H. Seyfert K. Böckmann J. Hofmann J. Lowsky G. Zobernig V.T. Cocconi T. Coghen V. Karimäki G. Kellner D.R.O. Morrison J. Zaorska 《Nuclear Physics B》1975,94(1):21-38
The production of is measured in π+p reactions at 16 GeV/c. The total strange particle cross section is found to be 4.0 ± 0.3 mb, about 20% of the inelastic cross section. Cross sections for single strange particles and for strange particle pairs are determined, both inclusively and as functions of the charged multiplicity. Relative production rates for different strange particle combinations are compared with the prediction of the isospin statistical model. Inclusive spectra for single particles are studied and it is found the KS0 are produced mostly in the forward hemisphere, most probably by fragmentation of the incident pion into . The Λ are mostly backwards, probably deriving from fragmentation of the proton into ΛK pairs. The tend to be produced forwards, but evidence is found for central production. Distributions in rapidity of the Λ particles from π+p interactions are compared in terms of the factorisation hypothesis. Results are given on the Λ transversal polarisation. 相似文献
4.
J. Bartke M. Deutschmann H.G. Kirk P. Sixel L. Becker H. Vogt R. Hartmann H. Plothow D. Kocher D.R.O. Morrison P. Porth K. Eskreys K. Olkiewicz K. Doroba T. Hofmokl 《Nuclear Physics B》1977,120(1):1-13
Interactions in which the baryon is emitted forwards in the c.m.s. are studied in 8 and 16 GeV/cπ+p collisions. These interactions are interpreted as representing baryon exchange. The properties of such off-shell N annihilation events are studied. It is found that the multiplicity distribution of the multi-pion system as a function of the effective mass for events with |upp| < 1 GeV2 is the same as for real annihilations. 相似文献
5.
M. Deutschmann R. Honecker K. Rumpf U. Kundt M. Walter U. Idschok R. Hartmann V.T. Cocconi T. Coghen S. Humble A. Kotański D.R.O. Morrison J. Figiel A. Guła P. Malecki B. Muryn L. Suszycki E. Leitner 《Nuclear Physics B》1975,85(1):31-38
The differential cross section for the charge-exchange process π+p → π0 (π+p) at 8, 16 and 23 GeV/c is presented for several regions of the π+p effective mass. It is found that the dip at t′ ≈ 0.6 (GeV/c)2 which is observed in the Δ(1236) mass band becomes a less pronounced structure in the higher mass regions. However, while the slope of the distributions in the near-forward direction decreases strongly with increasing π+p mass, there is no evidence that the observed structure moves to higher values of t′ as the π+p mass increases. These results are consistent with a Regge-exchange picture where the position of the dip is determined by the exchanged trajectory, but are inconsistent with a simple geometrical picture. 相似文献
6.
Raymond Critchley 《Physics letters. [Part B]》1978,78(4):410-412
The axial and trace anomalies for a real spin field interacting with a background gravitational field, as in simple supergravity, is computed. The axial anomaly result differs from that of Van Nieuwenhuizen and Vermaseren. 相似文献
7.
Excitation functions for 16O+p reactions have been measured with high energy resolution in the region of the first, second and seventh resonances in 17F at extreme backward angles. The observed resonance shapes have been analyzed with a single-level resonance formula taking the off-resonance spin-flip amplitude into account. The resonance parameters of the 17F first state studied with special emphasis are Ex = 11193.3 ± 2.3 keV, Γ = 200 ± 40 eV and Γp0 = 19 ± 3 eV. This result and other results are compared with previous studies and theoretical predictions. The comparison with data of the mirror nucleus 17O is discussed with respect to the observed charge asymmetry of the isospin-forbidden particle decay widths. 相似文献
8.
C. Evangelista B. Ghidini A. Palano V. Picciarelli G. Zito P. Mättig K. Müller E. Paul W. Rühmer B.R. French D.H. Miller W.A. Mitaroff C. Palazzi-Cerrina R. Strub A.S. Thompson P.L. Woodworth M. Edwards L. Pregernig 《Physics letters. [Part B]》1977,70(3):373-376
Inclusive production is studied in π?p interactions at 16 GeV/c with x? > 0.2. The is found to be pre-dominantly centrally produced with cross section for x? > 0.2 and compares closely to data on production in π+p interactions at the same energy. 相似文献
9.
M. Deutschmann G. Otter G. Rudolph L. Becker W. Lohmann E. Matthäus H.J. Schreiber G. Weigt V.T. Cocconi J.D. Hansen V. Karimäki D.R.O. Morrison D. Sotiriou P.J. Dornan B. Pollock P.R. Thornton D.J. Kocher P. Porth 《Nuclear Physics B》1974,81(1):1-17
Results on production in K?p → NKπ reactions at 16 GeV/c are presented. Total cross sections, differential cross sections and density matrix elements are determined. It is found that: (i) The cross section for K1?(890) p is consistent with containing two components, one due to natural parity exchange, falling slowly with increasing energy, the other, due to unnatural parity exchange, vanishing rapidly with increasing energy. For , the cross section decreases steadily as the energy increases. (ii) Natural spin-parity exchange dominates in the K1?(890) p channel, the unnatural exchange contribution being approximately (5±4)%. In , natural spin-parity exchange is only about (30±10)%. (iii) The reacton is dominated (95±5)% by isoscalar exchange. (iv) The effective trajectory involved in the I = 0 natural parity exchange is consistent with the ω-f trajectory. (v) Interference terms between exchanges with positive (f, πo,…) and negative (?o, ω,…) C-conjugation amount to (23±12) μb at 16 GeV/c. 相似文献
10.
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
11.
G. Perrin D. Lebrun J. Chauvin P. Martin P. De Santignon D. Eppel H.V. Geramb H.L. Yadav V.A. Madsen 《Physics letters. [Part B]》1977,68(1):55-57
Angular distributions for polarized proton inelastic scattering cross sections along with the analysing power for the reaction at Ep=42.5, 44.0 and 49.3 MeV have been measured. A semidirect reaction analysis augments the evidence for octupole giant resonance strength in the 30 to 50 MeV energy region. 相似文献
12.
13.
Supercurrents that provide irreducible off-shell representation of N-extended supersymmetry with maximum are constructed as bilinears of massless on-shell superfields. The corresponding prepotentials are derived and used to construct maximally gauge-invariant field theories with maximum . The construction of non-conformal theories using these irreducible field multiplets is discussed; in particular the superfield form of massive spin 1 is given for N = 2 and compensating fields are proposed for N = 4 Poincarésupergravity. We also show how the components of supercurrents may be simply obtained with the aid of the “tableaux calculus” and we work out in detail several N = 4 and N = 8 examples. 相似文献
14.
Supercovariant derivatives and supercovariant field strengths are used to put the fermionic equations of motion derived from supergravity theories in an elegant form. These results apply also to the SO(4) extended supergravity theory which is presented here. We discuss how to obtain more compact proofs of the invariance of the supergravity actions already known. In particular for the SO(2) theory a set of new auxilary fields is introduced which linearizes the equation of motion of the field. 相似文献
15.
H. Laven G. Otter G. Rudolph R. Klein H.J. Schreiber D.J. Kocher D.R.O. Morrison P. Schmid K.L. Wernhard R.M. Eason T.C. Bacon K.W.J. Barnham P.J. Dornan B. Pollock J. Macnaughton M. Markytan 《Nuclear Physics B》1977,127(1):43-56
The reactions (1) K?p → K+K?Λ and (2) have been studied on samples of 109 and 64 events, respectively, at 10 GeV/c and 125 and 69 events at 16 GeV/c, reasonably free from contaminations. The investigation of the first reaction uses also 84 events of the final state at 10 GeV/c. Analysis of the Van Hove plots indicates that the K+K?Λ and final states are produced by two main mechanisms: (i) a ΔQ = 0 process, with a strong diffractive component near threshold, involving the dissociations p → K+Λ in reaction (1) and in reaction (2) and (ii) a ΔQ = 1 process involving hypercharge exchange, and producing K+K? and systems in reactions (1) and (2), respectively, recoiling off the Λ. With increasing energy, this hypercharge exchange process decreases slowly when K+K? is produced, but fast where the production of , violating the Zweig rule, occurs. 相似文献
16.
The wavenumbers of the rotation-vibration lines of 14N16O are reported for the (2-0) and (3-0) bands. The full set of spectroscopic constants for the three bands (1-0), (2-0), and (3-0) has been determined with the method developed by Albritton, Schmeltekopf, and Zare for merging the results of separate least-squares fits. The vibrational constants ωe, ωexe, ωeye, and the vibrational dependence of the rotational constants have been deduced. The apparent spin-orbit constant and its centrifugal correction (including the spin-rotation constant) have a vibrational dependence of the following form: and ; the values of the constants in these two equations have been determined. 相似文献
17.
F.D. Becchetti P.R. Christensen V.I. Manko R.J. Nickles 《Physics letters. [Part B]》1973,43(4):279-283
The spectroscopic factors deduced from a finite-range DWBA analysis of the (16O, 15N) reaction show systematic discrepancies with those obtained from (τ,d), and (α,t) and (d,n) reactions depending on whether or . The results depend sensitively on the selection rules used, however. 相似文献
18.
H. Grässler R. Honecker H. Laven L. Becker R. Klein W. Lohmann H.J. Schreiber M.F. Hodous D.J. Kocher D.R.O. Morrison K.-L. Wernhard K.W.J. Barnham B. Pollock D.P. Dallman F. Mandl 《Nuclear Physics B》1978,136(3):386-400
A strong negative transverse polarization Pz is found for forward produced lambdas observed in 10 and 16 GeV/c K?p interactions. This indicates that exchanges of natural spin-parity are dominant in the production process. Using the polarization results, the distributions for natural and unnatural spin-parity exchanges are derived. For unnatural exchanges, a dip is observed at u′?0.3 GeV2, which can be explained as a nonsense-wrong-signature zero of the Nβ trajectory. The value of Pz for forward producted lambdas is constant with energy. This is in agreement with the triple-Regge model prediction, as is the fact that Pz is constant as a function of . The two non-transverse polarization components, Px and Py, have been measured and are found to be consistent with zero for all x values, unlike Pz. 相似文献
19.
W.A. Sterrenburg S. Brandenburg J.H. van Dijk A.G. Drentje M.B. Greenfield M.N. Harakeh H. Riezebos H. Sakai W. Segeth S.Y. van der Werf A. van der Woude 《Nuclear Physics A》1984,420(2):257-284
The nucleus 16F was studied via the 16O(3He, t) reaction at 81 MeV. Differential cross sections for many states were obtained and interpreted with DWBA calculations, using microscopic wave functions and an effective projectile-nucleon interaction. Proton decay to several states in 15O was observed and angular correlations for protons in coincidence with tritons detected at θ = 0° were measured. Several spin-parity assignments have been made. The distribution of isovector ΔL = 1 strength could be deduced. The analog of the giant dipole resonance ( is strongly excited. The magnetic quadrupole strength has two strong components, one low, at Ex = 0.424 MeV, and one high, at . Evidence is given for a proportionality between cross section and M2 strength for transitions to Jπ = 2? states, which possibly make the (3He, t) reaction a suitable tool for determining quantitatively isovector M2 (or Bij) strengths. 相似文献
20.
P.V. Chliapnikov P.A. Gorbunov S.A. Gumenyuk V.V. Kniazev B.A. Manyukov V.M. Perevoztchikov V.N. Riadovikov V.A. Uvarov M.L. Faccini-Turluer M. Loret L. Mosca H. Blumenfeld J. Laberrigue C. Dujardin F. Grard J. Skura R. Windmolders M. Csejthey-Barth M. Gysen 《Nuclear Physics B》1977,131(1):93-106
A study of the inclusive and semi-inclusive Λ and production in K+p interactions at 32 GeV/c is presented. The inclusive cross sections for Λ and amount to 0.78 ± 0.05 and 0.42 ± 0.04 mb thus showing a remarkable growth between 16 and 32 GeV/c with a factor of 1.7 for Λ and 2.8 for . Target and beam fragmentation processes are found to be dominant for Λ and production respectively with the following lower limits for the corresponding cross sections: and . Although the early scaling conditions are fulfilled for the Λ production in the target fragmentation region, and production in the beam fragmentation region, scaling is not observed between 16 and 32 GeV/c in the x and pT2 Feynman variables. The Λ production is found to be very similar in the K+p inclusive reaction at 32 GeV/c and in the semi-inclusive reaction at the same energy. The pair production cross section increases significantly in K+p interactions from 16 to 32 GeV/c where it reaches the value . The cross sections for Λ or produced in association with an identified proton are also given and discussed. 相似文献