A study of the reactions KN→Σ(1385)π between 0.6 and 1.2 GeV/c

An energy-dependent partial-wave analysis of the reaction $\text{K}\text{N}\text{→Σ(1385)π}$ has been performed in the energy region lying between 1.65 and 1.85 GeV. The resonant amplitudes of seven well known Y¹ resonances have been determined, and used to compute the corresponding (8) ? (10) SU (3) coupling constants.     

New measurement of (g−2) of the Muon

The g-factor anomaly, a≡(g?2)/2, has been measured for μ⁺ in the new Muon Storage Ring at CERN. The result is a = (1 165 895 ± 27) × 10^?9. This is (13 ± 29) × 10^?9 below the theoretical value which includes sixth-order QED terms and a hadronic contribution of (73 ± 10) × 10^?9.     

The anomalous magnetic moment of positive and negative muons

The anomalous g-factor a ≡ (g?2)/2 has been measured for muons of both charges in the Muon Storage Ring at CERN. The two results, a_μ⁺ = 1165910(12) × 10^?9 and a_μ^? = 1165936(12) × 10^?9, are in good agreement with each other, and combine to give a mean a_μ = 1165922(9) × 10^?9, which is very close to the most recent theoretical prediction 1165921(10) × 10^?9. For the experimental results, the total statistical and systematic error is given. The measurements thus confirm the remarkable QED calculation plus hadronic contribution, and serve as a precise verification of the CPT theorem for muons.     

Observation of the muonic decay of the charged intermediate vector boson

Muons of high transverse momentum p^μ_T have been observed in the large drift chambers surrounding the UA1 detector at the CERN 540 GeV pp? collider. For an integrated luminosity of 108 nb^?1, 14 isolated muons have been found with p_T > 15 GeV/c. They are correlated with a large imbalance in total transverse energy, and show a kinematic behaviour consistent with the muonic decay of the Intermediate Vector Boson W^± of weak interactions. The partial cross section is in agreement with previous measurements for electronic decays and with muon-electron universality. The W mass is determined to be m_W = 81⁺⁶_?7 GeV/c².     

Comparison of three-jet and two-jet cross sections in pp̄ collisions at the CERN SPS pp̄ collider

Results are presented on two-jet and three-jet cross sections, measured in the UA1 experiment at the CERN Super Proton Synchrotron (SPS) pp? Collider, at the highest available subprocess cms energies ($\text{s}\text{?}\text{>150}\text{GeV}$). Precise measurements of the two-jet angular distribution are consistent with previous results but show significant scale-breaking effects. The three-jet Dalitz plot and the three-jet angular distributions show evidence for final- and initial-state bremsstrahlung processes, in agreement with the leading-order QCD predictions. A comparison of the yield of wide-angle three-jet events with the yield of two-jet events at smaller scattering angles gives for the strong interaction coupling constant: $\text{α}{}_{\mathrm{<mtext>s</mtext>}}\text{(}\text{K}{}_{\mathrm{3J}}\text{K}{}_{\mathrm{2J}}\text{)=0.16±0.02±0.03}$ at Q²≈4000 GeV², where the factor $\text{K}{}_{\mathrm{3J}}\text{K}{}_{\mathrm{2J}}$ may plausibly be assumed to be close to unity.     

Evidence for the Bφ decay mode of the ω(1670)

Backward production of ω(1670) is observed in the reactions K^?p→φ⁺φ^?ω⁰Λ⁰ and K^?p→φ⁺φ^?φ⁰φ⁰ for |U'_Λ|<1.0 GeV². The cross section for the ω(1670) →φ⁺φ^?ω⁰ decay mode is 1.90±0.35 μb for 8.25 GeV/c incident K^?. Evidence is presented for the importance of the sequential decay, ω(1670) → Bφ → ωφφ with a branching ratio ω(1670) → Bφ/all ω(1670) → ωφφ=1.0±_0.25^0.00.     

Path integrals over the group manifolds

Particle motion in the SU(2) manifold is quantized by path integrals. It is shown that the Poschl-Teller, Wood-Saxon, and Rosen-Morse potentials are solved by relating their propagators to the path integrations over the SU(2) manifold. Examples with some other groups are mentioned.     

Path integrals and linear canonical transformations

For a system withN bosonic or fermionic degrees of freedom I calculate the coherent state propagator, i.e. the matrix element between coherent states of the evolution operator, for a general quadratic Hamiltonian plus a source term, using the holomorphic form of the path integral. The analysis and the result obtained are used to discuss the transformation properties of the path integral for linear canonical transformations (Bogoliubov-Valatin trfs), a preliminary to the formulation of a geometric theory of path integral quantization.

     

Closed path integrals and the quantum action

We suggest a closed form expression for the path integral of quantum transition amplitudes. We introduce a quantum action with parameters different from the classical action. We present numerical results for the harmonic oscillator with weak perturbation, the quartic potential, and the double well potential. The quantum action is relevant for quantum chaos and quantum instantons.     

Experimental tests of the factorisation of Regge trajectories in the proton fragmentation region

We present double differential cross sections for the reactions K^? + p → π^± + anything at 8.25 GeV/c. Using published data for reactions K⁺ + p→ π^? + anything and p + p → π⁺ anything we predict the differential cross sections for γ + p → π^? + anything, π^? + p → π^? + anything and π^? + p → π⁺ + anything in the target fragmentation region based on factorisation of the pomeron and Regge trajectories. Our predictions agree with the experimental data and support the hypothesis of factorisation of the Regge trajectories in the target fragmentation region.     

Path integrals for the quantum microcanonical ensemble

Path integral representations for the quantum microcanonical ensemble are presented. In the quantum microcanonical ensemble, two operators are of primary interest. First, rhoinsertion mark=delta(E-Hinsertion mark) corresponds to the microcanonical density matrix and can be used to calculate expectation values. Second, Ninsertion mark=Theta(E-Hinsertion mark) can give the number of states with energy E(n) and Theta(x,x('),E)=. A path integral formalism leads to exact integral representations for Omega(x,x('),E) and Theta(x,x('),E). We present both phase space and configuration space forms. For simple systems, such as the free particle and harmonic oscillator, exact solutions are possible. For more complicated systems, expansion schemes or numerical evaluations are required. A perturbative calculation and numerical integration results are presented for the quantum anharmonic oscillator.     

Search for a ΔΔ(1236) component of the deuteron

The dp → nnpπ⁺, dp → ppnπ⁰ and dp → pppπ^- reactions at 3.33 GeV/c deuteron momentum on the proton target were studied in order to search for a ΔΔ configuration in the deuteron. The frequent backward emission of the (pπ⁺), (nπ^o) and (pπ^?) systems in the deuteron rest frame was observed. The origin of the effect was analysed from the point of view of a possible ΔΔ admixture in the deuteron wave function. Some other sources which may contribute to the signal are indicated.     

The Weiss variation of the gravitational action

The Weiss variational principle in mechanics and classical field theory is a variational principle which allows displacements of the boundary. We review the Weiss variation in mechanics and classical field theory, and present a novel geometric derivation of the Weiss variation for the gravitational action: the Einstein–Hilbert action plus the Gibbons–Hawking–York boundary term. In particular, we use the first and second variation of area formulas (we present a derivation accessible to physicists in an “Appendix”) to interpret and vary the Gibbons–Hawking–York boundary term. The Weiss variation for the gravitational action is in principle known to the Relativity community, but the variation of area approach formalizes the derivation, and facilitates the discussion of time evolution in General Relativity. A potentially useful feature of the formalism presented in this article is that it avoids an explicit 3 \(+\) 1 decomposition in the bulk spacetime.     

Measurement of the polarization in the forward peak of π−p→K0λ at 5 GeV/c

The π^?p→K⁰λ polarization has been measured at 5 GeV/c in the range 0<?t<1.4 (GeV/c)². The polarization is small for ?t?0.4 (GeV/c)², becoming negative at the higher values of ?t.     

Finite-energy corrections and multiplicity fluctuations according to the Gottfried model of hadron-nucleus interactions

Finite-energy corrections and multiplicity fluctuations are considered in the Gottfried model for hadron-nucleus high-energy interactions. The results are that there are appreciable corrections at Serpukhov-NAL energies, such that the Gottfried parameter is ν = 0.25–0.27 instead of, e.g., ν = 0.38, in better agreement with presently available experimental results for proton-nucleus collisions. Further, the sensitivity of the model to some of the input parameters results in appreciable fluctuations in multiplicity, the multiplicity distribution of the part stemming from repeated collisions inside the nucleus being at least as broad as a Poisson distribution.     

Path integrals with arbitrary generators and the eigenfunction problem

We generalize the path integral formalism of quantum mechanics to include the use of arbitrary infinitesimal generators, thus providing explicit expressions for solutions of a wide class of differential equations. In particular, we develop a method of calculating the eigenfunctions of a large class of operators.     

Path integrals, the ABL rule and the three-box paradox

The three-box problem is analysed in terms of virtual pathways, interference between which is destroyed by a number of intermediate measurements. The Aharonov-Bergmann-Lebowitz (ABL) rule is shown to be a particular case of Feynman's recipe for assigning probabilities to exclusive alternatives. The ‘paradoxical’ features of the three box case arise in an attempt to attribute, in contradiction to the uncertainty principle, properties pertaining to different ensembles produced by different intermediate measurements to the same particle. The effect can be mimicked by a classical system, provided an observation is made to perturb the system in a non-local manner.     

A measurement of single electrons,electron pairs,and associated phenomena,in proton-proton collisions at the CERN ISR

Measurements of single-electron production in proton-proton collisions at the CERN ISR are presented for five centre-of-mass energies √s = 23.5, 30.6, 44.8, 52.7, and 62.4 GeV. The invariant cross sections for single electrons with transverse momenta of 0.60 to 4.7 GeV/c are given. Measurements of electron-positron pairs and measurements of charged hadrons produced in association with the single electrons, are also reported.     

More precise definition of the Gibbons-Hawking gravitational action

Hilbert and Einstein gravitational actions are compared to the Gibbons-Hawking action with the surface term. The equivalence principle is considered as an argument in favor of the choice of physical vacuum type and the choice of the action without the second derivatives of the tetrad potential, which coincides with the Hilbert action at weak Lorentz calibration of the tetrad: the co-closedness of one 1-form of the general tetrad expansion. The Gibbons-Hawking action is freed from the term artificially introduced by them, which limits its applicability in the general case.     

Path integrals on symmetric spaces and group manifolds

Invariant path integrals on symmetric and group spaces are defined in terms of a sum over the paths formed by broken geodesic segments. Their evaluation proceeds by using the mean value properties of functions over the geodesic and complex radius spheres. It is shown that on symmetric spaces the invariant path integral gives a kernel of the Schrödinger equation in terms of the spectral resolution of the zonal functions of the space. On compact group spaces the invariant path integral reduces to a sum over powers of Gaussian-type integrals which, for a free particle, yields the standard Van Vleck-Pauli propagator. Explicit calculations are performed for the case ofSU(2) andU(N) group spaces.