Is there a 2++ glueball at 1410 MeV?

A glueball component of theJ ^PC =2⁺⁺ q \(\bar q\) isoscalar states is discussed within a simple mass mixing model. As the third isoscalar necessarily present in theq \(\bar q\) ?gg mixing scheme we assumeG(1410) recently claimed by ACCMOR Collaboration in the π^? p→K _s ⁰ K _s ⁰ n data. The hypothesis is found to be compatible with the available experimental data, including two-photon decay widths and radiativeJ/ψ decays.     

Inclusive production ofK s 0 , K s 0 K s 0 andK *±(892) in\bar pp interactions at 3.0, 3.5, 4.0 and 4.5 GeV/c

InclusiveK _s ⁰ andK _s ⁰ K _s ⁰ production in \(\bar pp\) interactions at 3.0, 3.5, 4.0 and 4.5 GeV/c are studied. Cross sections ofK _s ⁰ , K _s ⁰ K _s ⁰ andK ^*±(892) are presented for each incident momentum. The production ofK _s ⁰ andK ^*±(892) through annihilation process is investigated. It is found that the annihilation process is dominant but decreases with incident momentum. The annihilation process is compared withe ⁺ e ^? interactions. Remarkable similarity between them is found in the \({{x_0 = 2E(K_s^0 )} \mathord{\left/ {\vphantom {{x_0 = 2E(K_s^0 )} {\sqrt s }}} \right. \kern-0em} {\sqrt s }}\) distribution. Events with two detectedK _s ⁰ 's are analyzed. The result shows theK _s ⁰ K _s ⁰ pairs are produced in the central region of c.m. system and there is a clearS ^* signal in theK _s ⁰ K _s ⁰ effective mass distribution.     

Mixing of intermediate bosons with Q\bar Q bound states

We discuss the effects of a close degeneracy between theZ ⁰ and vectorQ \(\bar Q\) bound states; large mixing effects can appear modifying mainly theQ \(\bar Q\) states (widths and couplings) and leading to curious structures inside theZ peak.     

On some properties of the neutron in the statistical model

Using the statistical model to arrive at |ψ(r)|² the square modulus of theS state wavefunction of the neutron, the electric dipole moment |d _n ^e | of the neutron as well as its baryon number violating lifetime have been estimated. The baryon asymmetry of the universe depending on |d _n ^e | has also been studied in this context.     

Demonstration of the origins of cooperativity within SU2×L 6 mapping over\left\{ {I\tilde H_\upsilon } \right\} Liouvillian carrier subspaces characterising the MQ-NMR cluster [A]6(L 6) and its\{ |kq\upsilon :[\tilde \lambda ] > > \} tensorial bases

The fundamental mappings over carrier subspace and substructures associated with \(\{ |kq\upsilon > > \} \) augmented spin algebras of Liouville space, and their mapping onto a subduced symmetry, are derived for [A]₆(L ₆) spin clusters within the combinatorial context of Rota-Cayley algebra over a field. Use of suitable lexical sets of combinatorialp-tuples (number partitions) over {|IM(M ₁?M _n )>}M, followed by the subsequent use ofL _n inner tensor product (ITP) algebra, allows the substructure of Liouville space to be derived. For SU2×L ₆ mapping over the simply-reducible \(\left\{ {I\tilde H_\upsilon } \right\}\) carrier subspaces, the \(D^k \left( {\tilde U} \right) \times \tilde \Gamma ^{\left[ {\tilde \lambda } \right]} \left( \upsilon \right)\) (L ₆) dual irreps, also arise as a consequence of the Liouville space recoupling termsv≡{k ₁?k _n } being distinct labels for \(\left\{ {I\tilde H_\upsilon } \right\}\) which are themselves amenible to combinatorial analysis within the concept of Rota-Cayley algebra. Hence, theL _n -induced symmetry aspects of multiquantum NMR density matrix formalisms and their dual \(\{ |kq\upsilon :[\tilde \lambda ] > > \} \) tensorial bases of spin cluster problems are derived and the nature of the cooperative, aspect between the individual symmetries comprising the duality is demonstrated, i.e. in the context of the operator bases of Liouville space. These practical arguments correlate, well with those based on an augmented boson pattern algebra derived from a Heisenburg algebra for superoperators, ?_±,?₀. An earlier, treatment of conventional Hilbert space SU2×L ₆ dualitycould only be realised in terms of standard SU2 boson algebra. Since the recoupling Rota-‘field’v for Liouville space is an explicit aspect of the dual mapping, a direct demonstration of cooperativity exists.     

Invariant states and conditional expectations of the anticommutation relations

The groupG of unitary elements of a maximal abelian von Neumann algebra on a separable, complex Hilbert spaceH acts as a group of automorphisms on the CAR algebraA(H) overH. It is shown that the set ofG-invariant states is a simplex, isomorphic to the set of regular probability measures on aw*-compact setS ofG-invariant generalized free states. The GNS Hilbert space induced by an arbitraryG-invariant state onA(H) supports a *-representation ofC(S); the canonical map ofA(H) intoC(S) can then be locally implemented by a normal,G-invariant conditional expectation.     

BFKL Pomeron in the reaction γ ⊥ * (Q 2)p→ρ ⊥ 0 p at large Q 2 and W

The reaction γ _⊥ ^* (Q ²)p→ρ _⊥ ⁰ p has been studied at large Q ² and W ²/Q ² and low momentum transfers to the nucleon, k _⊥ ² —that is, in the region where the Pomeron exchange mechanism is operative. At sufficiently large Q ², the Pomeron interacts with quarks occurring at small distances, whereby the hard component of the Pomeron is separated, so that the process is governed by the Pomeron of perturbative QCD (BFKL Pomeron). Our calculations indicate that, in vector-meson electroproduction at low k _⊥ ² , the perturbative regime cannot set in fast because, for Q ²≤100 GeV² and, accordingly, for W ²/Q ²≤10⁷, comparatively large distances of $\rho _{q\bar q} > 0.2$ fm are important.     

Further study of theE/f 1 (1420) meson in central production

We have studied the reactions \(({{\pi ^ + } \mathord{\left/ {\vphantom {{\pi ^ + } p}} \right. \kern-0em} p})p \to ({{\pi ^ + } \mathord{\left/ {\vphantom {{\pi ^ + } p}} \right. \kern-0em} p})(K\bar K\pi )p\) where the \(K\bar K\pi \) system is centrally produced, at 85 GeV/c and 300 GeV/c using the CERN Omega spectrometer. A spin-parity analysis of theK _S ⁰ K ^± π ^? system shows the presence of a strongJ ^PC=1⁺⁺ signal which we identify as theE/f ₁ (1420) meson. We also find evidence for the decayE/f ₁(1420)→K _S ⁰ K _S ⁰ π ⁰ which determines theC-parity of this state to be positive. Alternative explanations of the data have been tested and ruled out. Hence we obtain the quantum numbers of theE/f ₁ (1420) to beI ^G(J^PC)=0⁺(1⁺).     

The penetration parameter λ of the anomalousM1-conversion of the 482 keV transition in181Ta

Byγ- e _K ^? ande _K ^? -γ TDPAC measurements with the 133 keV–482 keV cascade of¹⁸¹Ta in a polycrystalline beryllium matrix theA ₂(e _K ^? )-coefficient of the 482 keV transition was determined as: A₂(482e _K ^? )=?0.095±0.015. The theoretical value is 6.0 times larger. A remeasurement of the E2/M1 mixing ratio of the same transition by integralγ- γ angular correlation measurements with a system of three 20 ccm Ge(Li)-detectors gave the result:δ(482)=4.96±0.25. Theα _K -coefficient was redetermined as:α _K (482)=0.0246±0.0018. From these data the penetration parameter:λ=157±11 is derived and compared with previously published values and theoretical estimates.     

Inclusive production ofK *(892) andΣ(1385) in\bar p p interactions at 3.6 GeV/c and a test of factorization hypothesis

We present a study of the inclusive production ofK ^*(892) and ∑^t+-(1385)+cc at 3.6 GeV/c from \(\bar p\) p interactions. The sensitivity of the exposure is 35.4 events/μb. Longitudinal and transverse momentum distributions are presented. The indirect production ofK _s ⁰ from parentK ^* and that of Λ's from parent Σ(1385) are studied. The shape of thex distribution of Λ's for \(p\xrightarrow{{\bar p}}\Lambda \) are calculated from \(p\xrightarrow{p}\Lambda \) and \(p\xrightarrow{{\pi ^ - }}\Lambda \) and compared with the experimental distributions. The difference of antiparticle production cross-section ofK _s ⁰ in the central region is compared with the expectation from Mueller-Regge formalism.     

Jets fromQ \bar Q P waves

We discuss angular distributions and some kinematic features for jets originating from the decay of orbitally excitedQ \(\bar Q\) states. These can be produced ine ⁺ e ^? storage rings via the radiative decay of the first radial excitedQ \(\bar Q\) vector meson. We further present the complete and explicit angular distribution for the cascade decaye ⁺ e ^? → 2³ S ₁ →γ ₁+³ P _j,³ P _j →γ ₂+1³ S ₁, 1³ S ₁ →μ ⁺ μ ^? in all casesj=0, 1, 2. These distributions serve as a test of the spinj of intermediate states inQ \(\bar Q\) systems. By the photon—gluon analogy they can successfully be applied to the jet process, too.     

Evidence for a newK * \bar K state at a mass of 1,530 MeV withIJ PC=01++ observed inK − p interactions at 4.2 GeV/c

Evidence is presented for a newK ^* \(\bar K\) +c.c. resonance with a mass of (1,526±6) MeV, a width of (107±15) MeV and quantum numbersIJ ^PC=01⁺⁺. We call itD′ meson. Initially it is observed as aK ^* \(\bar K\) +c.c. enhancement in the reactionsK ^? p→(K _s ⁰ K ^±π^?)Λ at 4.2 GeV/c. The isospin assignmentI=0 comes from its further observation in the reactionsK ^? p→(K _s ⁰ K ^±π^?)Σ ⁰ andK ^? p→(K _s ⁰ K ^±π^?)Σ(1,385)⁰ but not inK ^? p→(K ⁺ K ^?π^?)Σ⁺ orK ^? p→(K _s ⁰ K ^±π^?)Σ(1,385)⁺. A maximum likelihood analysis of the (K \(\bar K\) π) decay Dalitz plots in the reactionsK ^? p→(K _s ⁰ K ^±π^?) determines theJ ^PC of theD′ meson to be 1⁺⁺. A satisfactorySU(3) fit is obtained to a 1⁺⁺ nonet composed of theI-1A ₁, theI=1/2Q _A with theD(1,285) and theD′(1,526) as theI=0 members having a mixing angle close to the magic one.     

The mass gap for theP(φ)2 quantum field model with a strong external field

We consider theP(φ)₂ hamiltonian whose interaction density is given by $$\lambda P(\phi (x)) + \mu \phi (x)^k $$ wherek is odd and 1≦kP. For sufficiently large μ we show that there is a gap in the energy spectrum. In addition we obtain new regions of analyticity in λ and μ for the Schwinger functions and the pressure.     

Winkelkorrelationsmessungen an88Sr

The γγ ande _? ^KL γ directional correlations have been measured for the (898–1836) keV cascade in⁸⁸Sr following the decay of⁸⁸Y. The observed correlation coefficients areA ₂₂(γγ)=?0.0784±0.0042 andA ₂₂(e _? ^KL γ)=0.0102±0.0046. The γγ experiment is consistent with a mixing ratio δ(γ)=0.009±0.005 for the 898 keV transition. Using the result of thee _? ^KL γ experiment the most probable value of the ratio of the penetration matrix element to the normal γ-ray matrix element was determined to be η=0.03±0.30 showing a normal conversion process. This penetration parameter agrees with a hindrance factorH _W(E1)=2.1 · 10^?3 for theE1 transition.     

Theoretical studies of energy-energy correlation ine + e− annihilation

We calculate theO(α _s ² ) correction to the energy-energy corelation cross section ine ⁺ e^? annihilation using different resolution criteria in the limit of vanishing resolution cuts. We compare this in the back-to-back angular region with results of the logarithm approximation (LA) and deduce higher order corrections (beyondO(α _s ² )) from the LA formula. The final results are compared with recent TASSO data.     

The correlation between charge and energy flow within cascade models for quark and hadron jets

We consider the ratio \(\frac{{\Delta Q}}{{\Delta \varepsilon }}\) of the charge and energy fraction carried by particles in the angular interval ΔΩ with respect to the jet axis, where we assume a recursive scheme for the hadron cascade. A measurement of this ratio inep andvp collisions determines the quark chargeQ _q at any angle ΔΩ and ine ⁺ e ^?-annihilations alsoQ _q ⁴ can be obtained. In hadron hadron collisions this ratio discriminates in a very direct way between different production models. We consider the “stopping quark” model, the “two dual sheet” model, and finally a leading cluster model. More data on \(\frac{{\Delta Q}}{{\Delta \varepsilon }}\) would be desirable at higher energies in particular for meson beams.     

A simple idea in explaining the baryon production of\bar p p interactions by the quark framework

A simple idea about quark-quark or quark-diquark reaction mechanism is proposed to predict thex _F spectra in \(\bar p\) p interactions. Over a wide energy range, it is applied to the strange particle production in \(\bar p\) interactions and found that it reproduces well thex _F spectra of strange particleK _s ⁰ ,K ^*± ,Ε ⁰ andΣ ⁺(1385) productions, especially, including the leading effect in the case of strange baryonΕ ⁰,Σ ⁺(1385) productions.     

On the nature ofC(1480) resonance

The dynamic interpretation of theC(1480) resonance in the φπ⁰ mass spectrum is discussed in detail. It is shown thatC(1480) can result from a rare decay ρ′(1600)→φπ⁰ originating from OZI rule violation due to coherently amplified intermediate processes ρ′(1600)→ \(K*\bar K + \bar K*K\) →φπ⁰ in the region of logarithmic singularity. Some checks of this interpretation ofC(1480) are given. It is shown that one cannot describe the φπ⁰ data by a nonresonant amplitude π⁰ p→( \(K*\bar K + \bar K*K\) )n→φπ⁰ n with Regge parametrizedK andK ^* exchanges in the block π^?π⁺→ \(K*\bar K + \bar K*K\) →φπ⁰. The decays ρ′(1600)→ωπ⁰, \(K*\bar K + \bar K*K\) ? η are also discussed.