Search results for "SCALAR"

Antiproton over proton and K$^-$ over K$^+$ multiplicity ratios at high $z$ in DIS

2020

The $\bar{\rm p} $ over p multiplicity ratio is measured in deep-inelastic scattering for the first time using (anti-) protons carrying a large fraction of the virtual-photon energy, $z>0.5$. The data were obtained by the COMPASS Collaboration using a 160 GeV muon beam impinging on an isoscalar $^6$LiD target. The regime of deep-inelastic scattering is ensured by requiring $Q^2$ > 1 (GeV/$c$)$^2$ for the photon virtuality and $W > 5$ GeV/$c^2$ for the invariant mass of the produced hadronic system. The range in Bjorken-$x$ is restricted to $0.01 < x < 0.40$. Protons and antiprotons are identified in the momentum range $20 ��60$ GeV/$c$. In the whole studied $z$-region, the $\…

Muon capture in11B

1971

In this paper the partial-capture rates of muons in11B going to11Be(g.s.) and11Be (320 keV), as well as the hyperfine effect in the transition to11Be*, are studied. Comparing these results with the beta-decay of11Be and the electromagnetic transition11Be* →11Be, we can derive some conclusions on the nuclear structure of the bound states of11Be. We also discuss some possible experiences which can give information on the pseudoscalar form factor in weak interactions.

Studies of Light Pseudoscalar Mesons at BESIII

2014

Studies of light pseudoscalar mesons are an important aspect of the physics program pursued at BESIII. In this presentation recent results from η and η′ decays and the current status of the γγ physics program will be discussed.

Measurement of the decay rate and form factor parameter in the decay KL→e+e−γ

1999

Abstract The decay rate of the neutral K meson KL→e+e−γ has been measured with the NA48 detector at the CERN SPS. A total of 6864 events has been observed with an estimated background of 10 events. The branching ratio is Γ(KL→e+e−γ)/Γ(KL→all) = (1.06±0.02stat±0.02sys±0.04calc)×10−5. The parameter α K ∗ describing the relative strength of the two contributing amplitudes to this decay through intermediate pseudoscalar or vector mesons was measured to be α K ∗ =−0.36±0.06stat±0.02sys.

Measurement of the decay distribution of η′ → π+π−γ and evidence for the box anomaly

1997

Abstract The distribution of m ( π + π − ) in the decay η ′ → π + π − γ has been measured with the Crystal Barrel detector. The results are based on a total of 7392 observed η′ decays. The box anomaly constant is extracted from this and its value is found to agree well with theoretical expectations. The pseudoscalar nonet parameters ( f 1 , f 8 and θ PS ) are determined. Finally, we find that there is a problem of consistency between QCD and the standard VDM assumption.

Determination of the Pseudoscalar Decay Constant fDs+ via Ds+→μ+νμ

2020

NonleptonicKdecay rate in terms of spectral-function integrals: A short-distance approach

1977

In unified gauge theories of the weak and electromagnetic interactions it is shown that the matrix element for the decay ${K}_{S}^{0}\ensuremath{\rightarrow}2\ensuremath{\pi}$ can reliably be expressed in terms of integrals over spectral functions if (i) modified spectral-function sum rules of the Das, Mathur, and Okubo type are valid, or if (ii) the strong interactions are asymptotically free and the Glashow-Iliopoulos-Maiani mechanism holds. In these cases the contributions of the low-lying pseudoscalar and vector mesons to the spectral-function integrals suffice to account for the decay rate.

Measurement of the π0, η, η′ Transition Form Factors at BABAR

2013

Abstract Measurements of the transition form factors of the pseudoscalar mesons π 0 , η, η ′ have been carried out by the BABAR collaboration at the SLAC B-factory PEP-II. The form factors F ( Q 2 ) were measured in two-photon processes covering the kinematic range 4 GeV 2 Q 2 40 GeV 2 . For the π 0 form factor, results are significantly higher than predicted by Brodsky and Lepage assuming an asymptotic distribution amplitude. Data also suggest that the asymptotic regime of QCD is reached only at relatively high Q 2 . We also report on measurements of the η and η ′ transition form factors, which happen to feature a significantly different Q 2 behaviour than the one of the neutral pion.

Common fixed points for self mappings on compact metric spaces

2013

In this paper we obtain a result of existence of points of coincidence and of common fixed points for two self mappings on compact metric spaces satisfying a contractive condition of Suzuki type. We also present some examples to illustrate our results. Moreover, using the scalarization method of Du, we deduce a result of common fixed point in compact cone metric spaces.

Immersions of compact riemannian manifolds into a ball of a complex space form

1997

There are some classical theorems on non-immersibility of compact riemannian manifolds with sectional curvature bounded from above given by Tompkins, O’Neill, Chern, Kuiper and Moore (see [3], pages 221-226). More recently, attention has been paid to the case of immersions into a geodesic ball of a simply connected space form, and some conditions of non-immersibility in such a ball have been proved. In particular, estimates for the mean curvature of a complete immersion into a geodesic ball have been obtained by Jorge and Xavier [11] and a corresponding rigidity theorem for compact hypersurfaces has been proved by Markvorsen [14]. In this paper we give the Kahler analogs of the theorems of …