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11.
R E Marshak 《Pramana》1988,31(1):9-39
This retrospective paper traces the conceptual evolution of two theories in which the author was involved—the two-meson theory
(with H A Bethe) in 1947 and the universal (V-A) theory of weak interactions (with E C G Sudarshan) in 1957—into the present-day standard model of particle interactions.
Part 1 is entitled ‘From the pion to QCD and pseudo-Goldstone bosons” and Part 2 “From the muon and neutrino to QFD and chiral
anomalies’.
Adapted from two lectures delivered at the University of Rochester in October, 1987. 相似文献
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Longley NP Bode CR Border PM Courant H DeMuth DM Gray RN Johns K Kasahara SM Lowe MJ Marshak ML Miller WH Mualem L Peterson EA Roback DM Ruddick K Schmid DJ Schub MH Shupe MA Vassiliev V Villaume G Werkema SJ Ayres DS Fields TH Gallagher HM Goodman MC Lopez FV May EN Price LE Seidlein RV Thron JL Trost H Uretsky JL Allison WW Barr GD Brooks CB Cobb JH Giller GL Stassinakis A Thomson MA West N Wielgosz U Alner GJ Cockerill DJ Cotton RJ Garcia-Garcia C Litchfield PJ Pearce GF Ewen B Kafka T 《Physical review D: Particles and fields》1995,52(5):2760-2765
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M. Zielinski D. Berg C. Chandlee S. Cihangir T. Ferbel J. Huston T. Jensen F. Lobkowicz T. Ohshima P. Slattery P. Thompson B. Collick S. Heppelmann M. Marshak E. Peterson K. Ruddick A. Jonckheere C. A. Nelson Jr. 《Zeitschrift fur Physik C Particles and Fields》1986,31(4):545-548
Using data on coherent production of π+π+π- systems in π+ collisions with nuclei we exclude the existence ofJ PC=1?+,I=1, exotic hybrid mesons with masses below 1.5 GeV and widths greater than 20 MeV, provided that their primary coupling is to πρ systems. Hybrid states with just such properties have recently been predicted from arguments based on QCD sum rules. Our experimental limit is based on Primakoff production of these states, and on an argument using vector dominance to relate their radiative widths to πρ channels. There has been increasing interest of late in the existence of hybrid states, which, in the case of mesons, contain a valence gluon in addition to aq \(\bar q\) pair in a color-octet state [1–5]. The pursuit of spectroscopic gluon degrees of freedom has been strongly motivated by the general QCD picture of hadrons, as well as by many specific calculations based on QCD sum rules, lattice simulations, and more phenomenological approaches such as QCD-bag models. Although much effort, both thoretical and experimental, has been devoted to the spectroscopy of glueballs, for which several candidates exist [6], it has also been realized that hybrid states may be as amenable to discovery, and perhaps less ambiguous to interpretation. 相似文献
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Conclusion In conclusion we suggest that nuclear orientation is a useful technique for determining nuclear spin structures. For a known hyperfine interaction atomic magnetic structures may also be deduced. Measurements on antiferromagnets and the rare earth magnet holmium demonstrate the method, although in the latter case the turn angle cannot be determined because of the limitation of L2 radiation. These experiments show that nuclear orientation can at least complement neutron diffraction and at best furnish information about magnetic structure when the latter technique is not applicable. We intend to study other rare earth magnets and more complicated antiferromagnetic structures. 相似文献
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We seek an interpretation of the U(1) part of the electroweak symmetry group in terms of the quantum number B ? L. We show that the electroweak symmetry group, for which U(1) can be interpreted as a local B ? L symmetry, is the left-right symmetry group SU(2)L × SU(2)R × U(1)L+R. The equating of UL+R(1) to UB?L(1) should lead to physical consequences which are not shared by standard gauge theory. B ? L may also help to explain the inversion of quark and lepton mass spectra. 相似文献
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Hirsekorn KF Veige AS Marshak MP Koldobskaya Y Wolczanski PT Cundari TR Lobkovsky EB 《Journal of the American Chemical Society》2005,127(13):4809-4830
Olefin complexes (silox)(3)M(ole) (silox = (t)Bu(3)SiO; M = Nb (1-ole), Ta (2-ole); ole = C(2)H(4), C(2)H(3)Me, C(2)H(3)Et, C(2)H(3)C(6)H(4)-p-X (X = OMe, H, CF(3)), C(2)H(3)(t)Bu, (c)C(5)H(8), (c)C(6)H(10), (c)C(7)H(10) (norbornene)) rearrange to alkylidene isomers (silox)(3)M(alk) (M = Nb (1=alk), Ta (2=alk); alk = CHMe, CHEt, CH(n)Pr, CHCH(2)C(6)H(4)-p-X (X = OMe, H, CF(3) (Ta only)), CHCH(2)(t)Bu, (c)C(5)H(8), (c)C(6)H(10), (c)C(7)H(10) (norbornylidene)). Kinetics and labeling experiments suggest that the rearrangement proceeds via a delta-abstraction on a silox CH bond by the beta-olefin carbon to give (silox)(2)RM(kappa(2)-O,C-OSi(t)Bu(2)CMe(2)CH(2)) (M = Nb (4-R), Ta (6-R); R = Me, Et, (n)Pr, (n)Bu, CH(2)CH(2)C(6)H(4)-p-X (X = OMe, H, CF(3) (Ta only)), CH(2)CH(2)(t)Bu, (c)C(5)H(9), (c)C(6)H(11), (c)C(7)H(11) (norbornyl)). A subsequent alpha-abstraction by the cylometalated "arm" of the intermediate on an alpha-CH bond of R generates the alkylidene 1=alk or 2=alk. Equilibrations of 1-ole with ole' to give 1-ole' and ole, and relevant calculations on 1-ole and 2-ole, permit interpretation of all relative ground and transition state energies for the complexes of either metal. 相似文献
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We have conducted a search for globally supersymmetric preon models with gauged colour-flavour symmetries. Theories with both
two- and three-preon composites, and colour-flavour groups from E6 down to the standard model, are examined under the following conditions: asymptotically-free metacolour, anomaly-free gauged
symmetries, and Pauli principle obeyed. It is found that there are no models with three or more supersymmetric families. If
supersymmetry is broken, one model with four families emerges. The purely fermionic preon theories can also be considered
as the light sector of a chiral supersymmetric theory, with supersymmetry breaking at the preon level. 相似文献
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