125436491
Study of xi(2230) produced in J/psi radiative decay process
The processes e(+) + e(-) --> J / psi --> + X, X --> p (p) over bar are discussed using the generalized moment analysis method. The moment expressions of the above processes are given. And they are used to determine the spin of the resonance X decaying to p (p) over bar. The helicity amplitude ratios of the above processes in terms of moment expressions are also given.
121187481
A test of the glueball theory for the ξ(2230)
Abstract The possibility that the ξ(2230) is considered as a glueball is discussed in the framework of a nonrelativistic potential model [D. Robson, Nucl. Phys. B 130 (1977) 328] of the glueball with massive constituent gluons by using the experimental data from the Mark III Collaboration. The ratios of the helicity amplitude are calculated. The results are that the theoretical values cannot be consistent with the data if the ξ(2230) is a 2 ++ glueball in a pure S wave and the theoretical values are in excellent agreement with the data if the ξ(2230) is a 2 ++ glueball in a mixture between the S wave and two D waves or a 4 ++ glueball in a pure D wave.
45380547
Glueball components of the meson f2(1270).
It is shown that in order to explain the ratios {ital x} and {ital y} of the helicity amplitudes for the process {ital J}/{psi}{r arrow}{gamma}+{ital f}{sub 2}(1270) and the experimental datum {ital R}={ital B}({psi}{prime}({bold 3685}){r arrow}{gamma}+{bold f}{sub {bold 2}}({bold 1270}))/{ital B}({ital J}/{psi}{r arrow}{gamma}+{ital f}{sub {bold 2}}({bold 1270})) =(9{plus minus}3)% in terms of the mixture between the meson {ital f}{sub 2}(1270) and a 2{sup ++} glueball, two {ital D}-wave components have to be considered in addition to the {ital S}-wave component of the 2{sup ++} glueball.
18519588
On the mass relation of a meson nonet
It is pointed out that the omission of the effects of the transition between quarkonia or the assumption that the transition between quarkonia is flavor-independent would result in the inconsistent results for the pseudoscalar meson nonet. It is emphasized that the mass relation of the non-ideal mixing meson nonets should incorporate the effects of the flavor-dependent transition between quarkonia. The new mass relations of a meson nonet axe presented.
18104286
MODIFICATION OF KAWAI MODEL ABOUT THE MIXING OF THE PSEUDOSCALAR MESONS
The Kawai model describing the glueball–quarkonia mixing is modified. The mixing of η, η′ and η(1410) is re-investigated based on the modified Kawai model. The glueball–quarkonia content of the three states is determined from a fit to the data of the electromagnetic decays involving η, η′. Some predictions about the electromagnetic decays involving η(1410) are presented.
119699165
STUDY ON HADRONIC DECAY OF THE LOWEST LYING GLUEBALLS WITH JPC=even++ TO TWO PSEUDOSCALAR MESONS
Taking into account the possible glueball component in the final state mesons, we investigate the hadronic decay modes of the lowest lying glueballs (G) with JPC=even++ to two pseudoscalar mesons (PP). The naive estimations of $\frac{\tilde\Gamma(G\rightarrow PP)}{\tilde\Gamma(G\rightarrow K\bar K)}$ for scalar and tensor glueballs are given.
119220125
Can spacetime curvature induced corrections to Lamb shift be observable?
A bstractThe Lamb shift results from the coupling of an atom to vacuum fluctuations of quantum fields, so corrections are expected to arise when the spacetime is curved since the vacuum fluctuations are modified by the presence of spacetime curvature. Here, we calculate the curvature-induced correction to the Lamb shift outside a spherically symmetric object and demonstrate that this correction can be remarkably significant outside a compact massive astrophysical body. For instance, for a neutron star or a stellar mass black hole, the correction is ~ 25% at a radial distance of 4GM/c2, ~ 16% at 10GM/c2 and as large as ~ 1.6% even at 100GM/c2, where M is the mass of the object, G the Newtonian constant, and c the speed of light. In principle, we can look at the spectra from a distant compact super-massive body to find such corrections. Therefore, our results suggest a possible way of detecting fundamental quantum effects in astronomical observations.
16705538
PQCD study of the BSL and nc controversy in inclusive B decays
We calculate the semileptonic branching fraction and charm yield from inclusive $B$ decays using the formalism of perturbative QCD. For nonleptonic decays, we employ the modified factorization theorem, in which Wilson coefficients evolve with the characteristic scales of the decay modes. It is found that the decay rate of the single-charm mode $\stackrel{\ensuremath{\rightarrow}}{b}c\ifmmode \bar{u}\else \={u}\fi{}d$ is enhanced, and a lower ${B}_{\mathrm{SL}}$ is obtained without increasing ${n}_{c}.$ This conclusion differs from the usual one, where the $\stackrel{\ensuremath{\rightarrow}}{b}c\overline{c}s$ mode is increased. Our result for the $B$ meson lifetime is also consistent with the data.
119198751
Minimal flavor violation in the lepton sector of the Randall–Sundrum model
Abstract We propose a realization of Minimal Flavor Violation in the lepton sector of the Randall–Sundrum model. With the MFV assumption, the only source of flavor violation are the 5 D Yukawa couplings, and the usual two independent sources of flavor violation are related. In the limit of massless neutrinos, the bulk mass matrices and 5 D Yukawa matrices are simultaneously diagonalized, and hence the absence of FCNCs. In the case of massive neutrinos, the contributions to FCNCs in the charged lepton sector are highly suppressed, due to the smallness of neutrino masses. In addition, the MFV assumption also allows suppressing one-loop charged current contributions to flavor changing processes by reducing the size of the Yukawa couplings, which is not possible in the generic anarchical case. We found that the first KK mass scale as low as ∼ 3 TeV can be allowed. In both cases, we present a set of numerical results that give rise to realistic lepton masses and mixing angles. Mild hierarchy in the 5 D Yukawa matrix of O ( 25 ) in our numerical example is required to be consistent with two large and one small mixing angles. This tuning could be improved by having a more thorough search of the parameter space.
118968256
Determination of the HQET parameters from the B ---> X(s) gamma decay
We combine the resummations for radiative corrections and for the heavy quark expansion to study the inclusive radiative decay $B \to X_s\gamma$. The infrared renormalon ambiguity is also taken into account. Including both theoretical and experimental uncertainties, we determine the allowed domain for the HQET parameters ${\bar \Lambda}$ and $\lambda_1$ centered at ${\bar \Lambda}=0.65$ GeV and $\lambda_1=-0.71$ GeV$^2$.
119222434
Quantum Modifications to Gravity Waves in de Sitter Spacetime
We treat a model in which tensor perturbations of de Sitter spacetime, represented as a spatially flat model, are modified by the effects of the vacuum fluctuations of a massless conformally invariant field, such as the electromagnetic field. We use the semiclassical theory of gravity with the expectation value of the conformal field stress tensor as a source. We first study the stability of de Sitter spacetime by searching for growing, spatially homogeneous modes, and conclude that it is stable within the limits of validity of the semiclassical theory. We next examine the modification of linearized plane gravity waves by the effects of the quantum stress tensor. We find a correction term which is of the same form as the original wave, but displaced in phase by {pi}/2, and with an amplitude which depends upon an initial time. The magnitude of this effect is proportional to the change in scale factor after this time. We discuss alternative interpretations of this time, but pay particular attention to the view that this is the beginning of inflation. So long as the energy scale of inflation and the proper frequency of the mode at the beginning of inflation are well below the Planckmore » scale, the fractional correction is small. However, modes which are trans-Planckian at the onset of inflation can undergo a significant correction. The increase in amplitude can potentially have observable consequences through a modification of the power spectrum of tensor perturbations in inflationary cosmology. This enhancement of the power spectrum depends upon the initial time, and is greater for shorter wavelengths.« less