共查询到20条相似文献,搜索用时 890 毫秒
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J. Kogut M. Stone H.W. Wyld S.H. Shenker J. Shigemitsu D.K. Sinclair 《Nuclear Physics B》1983,225(3):326-370
We study chiral symmetry breaking (χSB) in SU(2) lattice gauge theory with quarks in the , and l = 2 representations of the color group. We perform Monte Carlo evaluations of in the quenched approximation and extract the relevant length scales for χSB. We revise a previous estimate for the ratio between the chiral symmetry restoration temperatures for fundamental and adjoint quarks and obtain . Our results for the higher representations, , are consistent with Casimir scaling and give C2gmom2 ~ 4. Many aspects of our calculational method are explained in detail. The issues discussed include the relation between χSB in the quenched approximation and the spectrum of the Dirac operator, the flavor symmetries of euclidean staggered fermions, estimates of finite-size effects and the reliability of m → 0 extrapolations on finite lattices. 相似文献
3.
W. Braunschweig H.-U. Martyn H.G. Sander D. Schmitz W. Sturm W. Wallraff K. Berkelman D. Cords R. Felst E. Gadermann H. Hultschig P. Joos W. Koch U. Kötz H. Krehbiel D. Kreinick W.A. McNeely K.C. Moffeit S. Yamada 《Physics letters. [Part B]》1977,67(2):243-248
The three photon final state produced in e+e? collisions has been measured at the mass of the resonance using the nonmagnetic part of the double arm spectrometer DASP. The decays and πoγ were observed and their branching ratios are given. A four standard deviation signal was observed in the γγ mass spectrum at a mass of (2.83 ± 0.03) GeV. An upper limit is given for the direct decay . 相似文献
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K.S. Narain 《Nuclear Physics B》1984,243(1):131-156
The partition function in the multi-instanton background for the supersymmetric CPN?1 model is calculated and is shown to be supersymmetry invariant. This is used to calculate Green's function involving N pairs of , and this turns out to be independent of the positions. A possible interpretation is that the composite field acquires a vacuum expectation value. The results are in agreement with those obtained in the 1/N expansion. 相似文献
5.
The effect of virtual light quark loops on the chiral phase transition in lattice QCD with staggered fermions is investigated by employing the pseudo-fermion Monte Carlo method on a 63 × 2 lattice. The variation in the order parameter is found to become less sharp than the quenched case, indicating a second order chiral phase transitioon in the full theory. 相似文献
6.
Edward Witten 《Nuclear Physics B》1978,145(1):110-118
In the two-dimensional SU(N) Thirring model, the 1/N expansion seems to predict spontaneous breaking of the continuous chiral symmetry. This is impossible in two-dimensions. Reasoning along the lines of Berezinski, Kosterlitz and Thouless for the two-dimensional XY model, we argue that, in fact, rather than showing long-range order, vanishes in this model as |x|?1/N at large |x|. The 1/N expansion is, in fact, a rather good guide to the properties of this model. 相似文献
7.
W. Braunschweig H.-U. Martyn H.G. Sander D. Schmitz W. Sturm W. Wallraff K. Berkelman D. Cords R. Felst E. Gadermann B. Gittelman H. Hultschig P. Joos W. Koch U. Kötz H. Krehbiel D. Kreinick W.A. McNeely S. Yamada 《Physics letters. [Part B]》1976,63(4):487-490
Branching ratios have been determined for the decays of and ψ ′ into π+π?, K+K?, , π±?? and . Results on a search for other two body decays of and ψ′ are given. Also presented are values for the π and K from factors at . 相似文献
8.
Ikuo Ichinose 《Nuclear Physics B》1985,249(4):715-732
U(N) and SU(N) lattice QCD are considered. By using a method of the strong-coupling expansion, the effective lagrangian of hadrons is calculated up to the first order in 1/(g2N). For the Susskind lattice fermions, it is shown that chiral symmetry is spontaneously broken and as a result there appears the Nambu-Goldstone boson (pion). The fermion condensation 〈t>, the masses of hadrons and the pion decay constant are calculated and compared with the results of Monte Carlo (MC) simulations. In the strong-coupling region, our result of the order parameter 〈〉 coincides very well with that calculated by MC simulations. 相似文献
9.
J. Werle 《Physics letters. [Part B]》1977,71(2):357-359
Explicit solutions of a non-linear Dirac equation in the four-dimensional Minkowski space have been found. They are continuous eigenfunctions of spin , energy and parity, and are confined to the interior of a sphere of definite radius a, with no tails outside the sphere. They are called solitons in the paper though the name of spinor droplets or bags may be more appropriate. Because of the Lorentz covariance of the Dirac equations, arbitrarily moving solitons can be obtained from the rest system solutions by applying proper Lorentz transformations. 相似文献
10.
We study the Segal entropy of a normal state ψ on a W1-algebra with respect to a faithful normal semi-finite trace τ on and we give a unique characterization of this general entropy concept by means of some natural properties. 相似文献
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J Burmester L Criegee H.C Dehne K Derikum R Devenish G Flügge J.D Fox G Franke Ch Gerke G Horlitz Th Kahl G Knies M Rössler R Schmitz U Timm H Wahl P Waloschek K Wacker 《Physics letters. [Part B]》1977,68(3):283-286
We report on inclusive production of (3.1)-mesons observed in e+e?-annihilation in the energy range . After substraction of the radiative tail of the ψ(3.7) direct production of the (3.1) is found to be in the order of 0.1% of the total hadronic cross section. No enhancements are seen at and 4.4 GeV. The level is in agreement with expectations from violation of the Zweig-rule. 相似文献
12.
Takashi Okazaki Seiji Ōkubo Yūichi Hoshino Kanji Fujii 《Physics letters. [Part B]》1979,85(1):107-110
The validity of the assumption that decays into mesons proceed via ω, φ and ?0 poles followed by cascade decays is examined. is well reproduced by using and the B → ωπ helicity structure. The structure of OZI-violating transitions including the electromagnetic contribution is examined, and compared with the data on inclusive decay. 相似文献
13.
M.J. Corden J.D. Dowell D. Eastwood J. Garvey R.J. Homer M. Jobes I.R. Kenyon T. McMahon R.J. Vallance P.M. Watkins J.A. Wilson J. Gago M. Jung P. Sonderegger D. Treille P.L. Woodworth V. Eckardt J. Fent K.C.T.O. Sumorok 《Physics letters. [Part B]》1977,68(1):96-100
Measurements have been made of relative production cross sections of the by π±, K±, p and p? at 39.5 GeV/c incident on copper. production rates from π?, K? and p? are similar. The relative particle/anti-particle production cross sections for x>0 are , σ(K+)/σ(K?)=(0.85±0.5) and . The small p/p? cross section ratio disagrees with models of J/ψ production by gluon amalgamation. 相似文献
14.
After integration over the fermions in an SU(2) lattice gauge theory, the effective fermionic action may be expressed as a sum over all possible closed gauge field loops with corresponding weight factors. We approximate this sum and perform a Monte Carlo simulation of a coupled fermion-gauge system on a 44 lattice. We compare our results for 〈Seff〉 and for different values of the gauge field coupling β and fermion coupling κ with the free fermion theory on a lattice. 〈Seff〉 turns out to be quite small for . 相似文献
15.
We derive self-consistent solutions for Dirac particles coupled to constant SU(2) vector potentials. Such solutions can be identified as classical approximations to non-topological fermionic solitons. We discuss the stability of these states under quantum fluctuations. 相似文献
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In this article we apply a previously proposed defermionization method to the study of two-dimensional QED (massive Schwinger model). We find good evidence for the spontaneous breaking of axial symmetry, i.e., in the massless limit. 相似文献
17.
A value of or less for the ratio of the P level splittings in approximate agreement with the assignment of the states at 3.41, 3.50 and 3.55 to the 0++,and 2++ P-wave levels, is obtained with a short-range Coulomb (Lorentz vector) potential together with a long-range linear (Lorentz scalar) confining potential. The radiative transition widths Γ(ψ′ → 3.41 + γ), Γ(ψ′ → 3.50 + γ), Γ(χ′ → 3.55 + γ) are significantly smaller than those obtained in previous (one-channel) charmonium calculations. The best results were obtained by allowing the Coulomb coupling constant αs to have a momentum dependence suggested by asymptotic freedom formulae. 相似文献
18.
Edward Witten 《Nuclear Physics B》1978,142(3):285-300
We show that the two-dimensional model is, for N = 3, equivalent to the supersymmetric sine-Gordon equation, and for N = 4, equivalent to two decoupled sine-Gordon systems. In addition, we argue that the kinks of this model are isospinors, and we construct some of the higher conservation laws that are responsible for the exact solubility of this system. 相似文献
19.
W. Bartel P. Duinker J. Olsson D. Pandoulas P. Steffen J. Heintze G. Heinzelmann R.D. Heuer R. Mundhenke H. Rieseberg A. Wagner A.H. Walenta 《Physics letters. [Part B]》1977,68(5):489-504
The decay of J/ψ (3.1) into final states containing no charged particles has been studied experimentally. The partial decay width for the observed neutral decays is (470 ± 160) eV. The decay modes J/ψ → γη → 3γ and J/ψγη′ → 3γ are identified and the branching ratios , are derived. Upper limits for the decay modes J/ψ → γπ0 and J/ψ → γγ are given. 相似文献
20.
《Physics letters. [Part B]》1988,207(2):194-198
We argue that suppression observed recently in high energy oxygen-uranium collisions by the NA38 Collaboration at CERN need not imply that the quark-gluon plasma was produced. A considerable part of the effect may be caused by the disintegration of 's in collisions with dense hadronic matter (below the phase transition into quark-gluon plasma) produced simultaneously with in heavy ion interactions. 相似文献