Gravitational anomalies

It is shown that in certain parity-violating theories in 4k+2 dimensions, general covariance is spoiled by anomalies at the one-loop level. This occurs when Weyl fermions of $\text{spin}\text{-}\text{1}\text{2}\text{or}\text{-3}\text{2}$ or self-dual antisymmetric tensor fields are coupled to gravity. (For Dirac fermions there is no trouble.) The conditions for anomaly cancellation between fields of different spin is investigated. In six dimensions this occurs in certain theories with a fairly elaborate field content. In ten dimensions there is a unique theory with anomaly cancellation between fields of different spin. It is the chiral n = 2 supergravity theory, which is the low-energy limit of one of the superstring theories. Beyond ten dimensions there is no way to cancel anomalies between fields of different spin.     

Test of the Zweig rule in π−p interactions at 19 GeV/c

We have observed φ production in π^?p interactions at 19 GeV/c with (44±10) events in the final state φπ⁺π^?π^?p and (45±9) events in φK⁺K^?π^?p. The production ratios φπ⁺π^?π^?p/ωπ⁺π^?π^?p ≈ 0.005 and φK⁺K^?π^?p/?°K⁺K^?π^?p ≈ 0.45 agree with Zweig-rule expectations.     

A study of hadronic decays of the ϒ′

We present a detailed study of the decays ?′ → π⁺π^?? and ?′ → π⁰π⁰?, where the ? decays subsequently to e⁺e^? or μ⁺μ^?. The results are obtained from a sample of 146 000 ?′ decays observed with the CUSB detector at the Cornell Electron Storage Ring. We derive branching fractions of (18.9 ± 2.6)% for ?′ → π′π^?? and (10.3 ± 2.3)% for ?′ → π⁰π⁰?, and determined partial widths for these decays. Invariant mass and angular distributions of both the π⁺π^? and π⁰π⁰ systems are presented. We also set a limit on the branching fraction for ?′ → η? of less than 0.2% at the 90% confidence level.     

Experimental proof of the existence of the A1 meson

In partial wave analyses of the (π^?π^?π⁺) system, substantial shape changes of the 1⁺S (?π) intensity as a function of t, and relative phase changes of ≈ 90°, provide compelling evidence for a resonant A₁ of mass ≈ 1280 MeV and width ≈ 300 MeV.     

Nuclear spin of a new isomer in 119Cs and magnetic moment of 120Cs evidence for strongly deformed nuclear shapes of the light cesium isotopes

The nuclear spin, $\text{I =}\text{3}\text{2}$, of a new isomer in ¹¹⁹Cs and the magnetic moment, μ_I = 3.92(5) n.m., of ¹²⁰Cs have been determined in on-line ABMR experiments at the ISOLDE facility, CERN. The experimental data give evidence for strongly deformed nuclear shapes of the light cesium isotopes.     

Observation of antideuteron production in electron-positron annihilation at 10 GeV center of mass energy

The production of antideuterons has been observed in electron-positron annihilations at center-of-mass energies around 10 GeV. Antideuterons have been identified unambiguously by their energy loss in the drift chamber, their time-of-flight and the pattern of their energy deposition in the shower counters of the ARGUS detector. The production rate in the momentum range (0.6?1.8) GeV/c is (1.6_?0.7^+1.0) × 10^?5 per hadronic event.     

First observation of K X-rays from pp atoms

K and L series X-rays have been observed from p$\text{p}$ atoms formed in hydrogen gas at NTP in association with annihilations into neutral particles. The total K X-ray yield is (6.5 ± 3.2) × 10^?3 per stopped antiproton. A model-dependent fit of the K X-ray spectrum gives a K_α energy of 8.9±0.3 keV, corresponding to a strong interaction shift of (?0.5±0.3) keV.     

Diffractive production of 3π states at 63 and 94 GeV

Diffractive production of the 3π system has been studied at 63 and 94 GeV using a two magnet spectrometer with high, uniform acceptance. The total number of events used in the analysis is ～600 000. The A₂ meson is shown to be diffractively produced. The existence of a resonant component in both the 1⁺ and 2^? enhancements is established and resonance parameters for the corresponding A₁ and A₃ mesons are given. There are several indications in the data of states which would correspond to radial excitations in the quark model.     

Electroproduction of π+ mesons in the resonance region

Results on the reaction ep→e′nπ⁺ are presented in the mass range 1.355 ?W ?1.775 GeV at q₂=1GeV² and in the range 1.415 ? W ? 1.595 GeV at q²=0.6 GeV². From the angular distribution of the π⁺ meson the polarization terms σ_u + ?σ_L, σ_p and σ_I have been determined in the range of production angles 0 <θ_π⁺ ?63°     

A possible connection between the attenuations of the Coriolis interaction and the recoil term

The data require an appreciable attenuation of the recoil term in the particle-rotor model hamiltonian. This fact may be related to the necessity of attenuating the Coriolis interaction.     

Momentum transfer and product kinetic energies in the interaction of silver with 86 MeVA12C

Mean kinetic properties of target fragments have been derived from thick target-thick catcher recoil data in a study of the interaction of silver with $\text{86}\text{MeV}\text{A}$¹²C ions. The $\text{F}\text{B}$-ratios reach maximum values of ≈ 200, showing that the angular distributions in the laboratory system are strongly forward peaked. Heay products (A?70) are found to be produced in a normal spallation reaction. However, it is suggested that products found in the mass region A≈60 are to a large fraction binary fission products.     

3π resonances in 2− partial waves

The J^PC = 2^?+ partial wave intensities and their large phase changes prove the resonant nature of the A₃ meson (mass ≈ 1670 MeV, width ≈ 210 MeV). The decay modes are f⁰π, ?⁰π, and ?⁰π. Evidence is found for a further 2^? enhancement.     

Inclusive φ-meson production in 93 and 63 GeV hadron interactions

The inclusive reactions h+p→φ+X, (h=π^±,,K^±,p^±), are studied for 0?x_F?0.3 and p⊥ ? 1 GeV at 93 and and 63 GeV incident momentum. Differential cross sections dσ/dp_⊥² anddσ/dx_F are presented and are compared with predictions of the naive parton model.     

The reaction 16O(6Li,d)20Ne at 75 MeV

The angular distributions of the reaction ¹⁶O(⁶Li, d)²⁰Ne at 75 MeV for transitions to members of the ground state band are well fitted by exact finite-range DWBA calculations assuming a direct α-cluster transfer and yield spectroscopic factors in good agreement with shell-model predictions.     

The N = Z nuclide 74Rb with T,Iπ = 1, 0+

Improved experimental techniques have permitted the observation of the new nuclide ⁷⁴Rb with a half-life of 64.9 ± 0.5 ms, which represents the heaviest self-conjugate nucleus detected until now. The absenceof along-lived isomer indicates that the T = 0 state of ⁷⁴Rb lies a bove the T = 1 state. An upper limit of 10^?3 relative top ⁷⁴Rb can be placed on the yield of the (unobserved) mirror nucleus ⁷³Rb, and it appears likely that the limit of particle stability has been reached. The half-life of ⁷⁵Rb is 17.0 ± 1.0 s.     

A2 meson production at high energies in the reaction π−p→π−π−π+p

The A₂ meson is studied in the decay mode ?⁰π^? using partial wave analyses of 600 000 events from the reaction π^?p→π^?π^?π⁺p at 63 and 94 GeV incident momentum. Common production mechanisms are indicated for this resonance and diffractive 1⁺ and 2^? components.     

A study of trimuon events in 280 GeV muon interactions

In 280 GeV μ⁺ iron interactions the inelastic production of muon pairs has been observed in excess of QED processes. For energies greater than 20 GeV deposited in the target calorimeter the interactions are found to be mainly hadronic. Cross sections are presented for this process in the mass range 1?2.5 GeV/c² and in the kinematic regions covered by the apparatus acceptance. The data are in good agreement with a photon-gluon fusion model for charmed particle production.     

Transverse momentum of charged hadrons observed in deep inelastic muon scattering

The transverse momenta of charged hadrons produced in high energy muon-proton scattering have been studied. The average squared transverse momentum 〈p²_⊥〉 shows a strong dependence on z = E_h/v characteristic of intrinsic momentum effects and a significant rise as a function of s = W². The W², q², x and z dependences of the data are compared with the predictions of a perturbative QCD model.     

Decay of PSI and upsilon into a lepton pair and gluons

We calculate the decay of a heavy vector quarkonium state into a lepton pair and two gluon jets, in lowest order QCD. We present branching ratios, and the lepton pair spectrum as a function of its invariant mass, and of the missing mass recoiling against it.     

Interaction of the K0-K0 system with external fields

The energy-dependence of the $\text{K}{}^0\text{-}\text{K}{}^0$ parameters Δm, τ_S and η_+? suggested by Fermilab regeneration data is analyzed phenomenologically. Such variations with energy can arise from the interaction of the kaons with an external field or medium, and several specific examples are studied in detail.