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1.
Last year Polyakov discovered the important role the trace anomaly plays in the relativistic string theory. This result means that one has to add counter terms to the string lagrangian
L=Lstring+CL1,
, where L1 contains a cosmological term and a term from the trace anomaly. In the conformal gauge we have
L1=LLiouville.
. We give a conventional GGRT treatment of this modified lagrangian for the bosonic string. Under the assumption that the exact quantization of Liouville's equation does not yield any additional anomalies, we show that relativistic invariance requires the constant C to be C = 26 ? D48π, in agreement with Polyakov's result. For D < 26 the string acquires longitudinal modes, and our calculations show explicitly how the longitudinal component of the string receives the degrees of freedom from the Liouville variable. Under the boundary conditions yielding the lowest value of the classical Liouville hamiltonian, the mass spectrum starts with a tachyon m2 = ?1α′, independent of D. The lowest-lying longitudinal excitation is m2 = 1α′. These results are semiclassical. It is shown that an exact quantization of Liouville's equation could remove the tachyon state when D < 26.  相似文献   

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Using a solution to the inverse scattering problem we have generated phase-equivalent separable potentials in the 1S0 and 3S1?3D1 states, which have nearly the same singlet UPA form factors and deuteron parameters (ED, PD, QD, AS and ADAS) as the Reid soft-core potential. We compare our results for the binding energy of the triton and the neutron-deuteron doublet scattering length with the corresponding values for the Reid soft-core potential.  相似文献   

4.
The potential V(z) = C9z9 ? C3z3 is a reasonable parametrization of the atom-surface interaction. We evaluate the discrete spectrum En of bound states for this potential with arbitrary coefficients C9 and C3. The resulting form in the WKB approximation is En = ?D [1 ? (n + l2)L]6, where L depends on the mass and D is the well depth. We find that the exact solution of the Schrödinger equation can be written in the same form, with n shifted slightly by an amount δn, which we calculate. The results are applied to the case of He near a NaF surface, in which the calculated eigenvalue spectrum agrees well with experimental values.  相似文献   

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6.
The electroreflectance of Si under uniaxial stress has been measured in the 3.0–4.0 eV region at 77 K. The results indicate that the dominant structure in this energy region is attributed to Λv3Λc1 (or Lv3′Lc1 transition. The deformation potentials of these bands are determined to be D11 = -7 ± 3 eV, D33 = 4 ± 1 eV and D51 = 5 ± 2 eV.  相似文献   

7.
We extend the technique of Cremmer et al. to couple arbitrary chiral multiplets with supersymmetric Yang-Mills interactions to N = 1 supergravity. We present the general form of the lagrangian and the detailed form of the scalar potential is spelled out. In the case of N chiral multiplets, “minimally” coupled to supergravity, we derive, in the absence of gauge interactions, a model-independent mass formula Supertrace M2 = ΣJ(?)2J(2J + 1)mJ2 = 2(N ? 1)m322, where m32 is the gravitino mass. A concrete example of the super Higgs effect involving N chiral multiplets is exhibited.  相似文献   

8.
The supercurrent anomalies of the supercurrent Sμ of the supersymmetric Yang-Mills theory in Wess-Zumino gauge are computed using the supersymmetric dimensional regulator of Siegel. It is shown that γμSμ=0 and ?μSμ≠0 in agreement with an earlier calculation based on the Adler-Rosenberg method. The problem of exhibiting the chiral anomaly and a regulator for local supersymmetry suggests that the interpretation of dimensional reduction in component language is incomplete.  相似文献   

9.
The apparent absence of the decay τ → ντν?1?, where ? = e or μ andνi is the spin-zero supersymmetric partner of νi, implies that the νi masses are sufficiently large that the decay is suppressed (assuming the supersymmetric partners exist). We give the resulting limits, which depend on the mass of the W? (the supersymmetric partner of the W) which mediates the decay, and on whether one or both ν is massive. These are the only experimental limits on ν masses.  相似文献   

10.
《Nuclear Physics B》2002,636(3):465-496
Two different kinds of interactions between a Zn-parafermionic and a Liouville field theory are considered. For generic values of n, the effective central charges describing the UV behavior of both models are calculated in the Neveu–Schwarz sector. For n=2 exact vacuum expectation values of primary fields of the Liouville field theory, as well as the first descendent fields are proposed. For n=1, known results for sinh-Gordon and Bullough–Dodd models are recovered whereas for n=2, exact results for these two integrable coupled Ising–Liouville models are shown to exchange under a weak–strong coupling duality relation. In particular, exact relations between the parameters in the actions and the mass of the particles are obtained. At specific imaginary values of the coupling and n=2, we use previous results to obtain exact information about: (a) integrable coupled models like Ising–Mp/p′, homogeneous sine-Gordon model SU(3)2 or the Ising–XY model, (b) Neveu–Schwarz sector of the Φ13 integrable perturbation of N=1 supersymmetric minimal models. Several non-perturbative checks are done, which support the exact results.  相似文献   

11.
The experimental evidence for the Pauli quantization obeyed by the Rydberg spectrum of rubidium, in crossed electric and magnetic fields, is reported. When the external field perturbation associated with Zeeman and linear Stark effects are of the same order but small compared to the Coulomb binding energy, the energy levels of the system are given by En,k = -R/n2 + ɡK (ω2L + ω2E)12, where K is an integer ωL, ωE the Larmor and linear Stark frequencies respectively.  相似文献   

12.
If KS1,Lis a K1 resonance decaying into KS,L (the short- and long-lived kaon) and a neutral system So of pions, one can isolate the C-even and C-odd, crossed-channel contributions to KN → K1N by using the reactions KLN → KS1, LN whether So is a C-eigenstate, or a mixture of C-even and C-odd states. Applications to the production of K1(890) and the Q-meson are discussed, and simple numerical predictions made for QS,L production. Q-production data indicate approximate t-channel helicity conservation for the ω and P' exchanges at vertices involving a spin change, in similarity to the belief for the pomeron. QS,L production data can give information also on Q-decays.  相似文献   

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The microwave spectrum of MnO3F has been remeasured and several corrections and new results have been obtained: B0 = 4129.141 MHz, DJ = 1.12 kHz, DJK = 1.87 kHz; α3B = 8.622, α5B = ? 11.994, α6B = 6.042, |q5| = 16.005, and |q6| = 8.456 MHz.  相似文献   

16.
Let 0 ?q(x) ∈L1,loc(Rm),m? 1.Consider the operatorT0 = ?Δ+q with domain consisting of all bounded measurable functions u(x), x ∈ Rm, having bounded support, for which the distribution ?Δu+qu belongs to L2(Rm). The main result of the paper is essential self-adjointness of T0 in L2(Rm). The proof is independent of a method due to Kato who recently established the self-adjointness of a maximal Schrödinger operator corresponding to such potential.  相似文献   

17.
The v = 1 ← 0 vibration-rotation bands of the NS radical in the X2Π12 and X2Π32 electronic states were observed by using a tunable diode laser. From the least-squares analysis the band origins were determined to be 1204.2755(12) and 1204.0892(19) cm?1, respectively, for X2Π12 and X2Π32. The rotational and centrifugal distortion constants and the internuclear distance in the X2Π electronic state were obtained as follows: Be = 0.775549(10) cm?1, De = 0.00000129(33) cm?1, and re = 1.49403(4) A?, with three standard deviations indicated in parentheses.  相似文献   

18.
The simplest four-quark SU(2) ? U(1) models with an anomally-free heavy lepton sector can have two charged heavy leptons and one or two neutral leprons. Such models also explain the rise in R (the ratio of hadronic to muon pair production in e+e? collisions). We study some consequences of different choices of leptonic numbers for L1 and L2. In particular, we derive, the leptonic decay width when several final-stae leptons are massive; the cross section for e+e?L1L2 production; the branching ratio for e+e?L2L2e3μ+missing energy.  相似文献   

19.
The implications of a Z4 horizontal symmetry model of flavor mixing for CP violation are studied in the framework of minimal SU(2)L × SU(2)R × U(1)B – L gauge theory. We show that CP violation in this model arises purely from right-handed currents. We also note that spontaneous breaking of CP symmetry requires a fine tuning of coupling parameters to the level of ≈ (MWLMWR)2, which can be avoided by the inclusion of one additional singlet Higgs field, of the kind recently introduced for other purposes.  相似文献   

20.
The discrepancies concerning the optical and microwave values of B0 and D0 for the X3Σg? state of O2 have been removed by a nonlinear least-squares fit to all of the lines of the O2, b 1Σg+-X 3Σg? Red Atmospheric bands recorded by Babcock and Herzberg (Astrophys. J., 108, 167, 1948). The resulting values for B0″ and D0″ are in excellent agreement with the Raman and microwave values. Improved values are determined for B1″, D1″, γ1″ (spin-rotation), and ?1″ (spin-spin). Both γv″ and ?v″ increase in magnitude from v″ = 0 to v″ = 1. Improved Dunham Yi0 and Yi1 expansion coefficients are determined for the b 1Σg+ state, from which the Rydberg-Klein-Rees potential is constructed.  相似文献   

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