The cross section for ee+ e- → π+ π- J/ψ between 3.8 and 5.5 GeV is measured with a 967 fb(-1) data sample collected by the Belle detector at or near the Υ(nS) (n = 1,2,…,5) resonances. The Y(4260) ...state is observed, and its resonance parameters are determined. In addition, an excess of π+ π- J/ψ production around 4 GeV is observed. This feature can be described by a Breit-Wigner parametrization with properties that are consistent with the Y(4008) state that was previously reported by Belle. In a study of Y(4260) → π+ π- J/ψ decays, a structure is observed in the M(π(±)J/ψ) mass spectrum with 5.2σ significance, with mass M = (3894.5 ± 6.6 ± 4.5) MeV/c2 and width Γ = (63 ± 24 ± 26) MeV/c2, where the errors are statistical and systematic, respectively. This structure can be interpreted as a new charged charmoniumlike state.
We present the first model-independent measurement of the absolute branching fraction of the Λ(c)(+) → pK(-)π(+) decay using a data sample of 978 fb(-1) collected with the Belle detector at the KEKB ...asymmetric-energy e(+)e(-) collider. The number of Λ(c)(+) baryons is determined by reconstructing the recoiling D((*)-) pπ(+) system in events of the type e(+)e(-) → D((*)-) pπ(+)Λ(c)(+). The branching fraction is measured to be B(Λ(c)(+) → pK(-)π(+)) = (6.84 ± 0.24(-0.27)(+0.21))%, where the first and second uncertainties are statistical and systematic, respectively.
Spontaneous Lorentz invariance violation (SLIV) realized through a nonlinear tensor field constraint Hμν2=±M2 (M is the proposed scale for Lorentz violation) is considered in tensor field gravity ...theory, which mimics linearized general relativity in Minkowski space–time. We show that such a SLIV pattern, due to which the true vacuum in the theory is chosen, induces massless tensor Goldstone modes some of which can naturally be associated with the physical graviton. When expressed in terms of the pure Goldstone modes, this theory looks essentially nonlinear and contains a variety of Lorentz and CPT violating couplings. Nonetheless, all SLIV effects turn out to be strictly canceled in all the lowest order processes considered, provided that the tensor field gravity theory is properly extended to general relativity (GR). So, as we generally argue, the measurable effects of SLIV, induced by elementary vector or tensor fields, are related to the accompanying gauge symmetry breaking rather than to spontaneous Lorentz violation. The latter appears by itself to be physically unobservable, only resulting in a non-covariant gauge choice in an otherwise gauge invariant and Lorentz invariant theory. However, while Goldstonic vector and tensor field theories with exact local invariance are physically indistinguishable from conventional gauge theories, there might appear some principal distinctions if this local symmetry were slightly broken at very small distances in a way that could eventually allow one to differentiate between them observationally.
We search for bottomonium states in Υ(2S) → (bb)γ decays with an integrated luminosity of 24.7 fb(-1) recorded at the Υ(2S) resonance with the Belle detector at KEK, containing (157.8±3.6)×10(6) ...Υ(2S) events. The (bb) system is reconstructed in 26 exclusive hadronic final states composed of charged pions, kaons, protons, and K(S)(0) mesons. We find no evidence for the state recently observed around 9975 MeV (X(bb)) in an analysis based on a data sample of 9.3×10(6) Υ(2S) events collected with the CLEO III detector. We set a 90% confidence level upper limit on the branching fraction BΥ(2S) → X(bb)γ × ∑(i)BX(bb) → h(i) < 4.9×10(-6), summed over the exclusive hadronic final states employed in our analysis. This result is an order of magnitude smaller than the measurement reported with CLEO data. We also set an upper limit for the ηb(1S) state of BΥ(2S) → ηb(1S)γ × ∑(i)Bηb(1S) → h(i) < 3.7×10(-6).
Simultaneous measurement of tritium and (14)C would provide an added tool for tracing organic compounds through environmental systems and is possible via beta energy spectroscopy of sample-derived ...methane in internal-source gas proportional counters. Since the mid-1960's atmospheric tritium and (14)C have fallen dramatically as the isotopic injections from aboveground nuclear testing have been diluted into the ocean and biosphere. In this work, the feasibility of simultaneous tritium and (14)C measurements via proportional counters is revisited in light of significant changes in both the atmospheric and biosphere isotopics and the development of new ultra-low-background gas proportional counting capabilities for small samples (roughly 50 cc methane). A Geant4 Monte Carlo model of a Pacific Northwest National Laboratory (PNNL) proportional counter response to tritium and (14)C is used to analyze small samples of two different methane sources to illustrate the range of applicability of contemporary simultaneous measurements and their limitations. Because the two methane sources examined were not sample size limited, we could compare the small-sample measurements performed at PNNL with analysis of larger samples performed at a commercial laboratory. These first results show that the dual-isotope simultaneous measurement is well matched for methane samples that are atmospheric or have an elevated source of tritium (i.e. landfill gas). However, for samples with low/modern tritium isotopics (rainwater), commercial separation and counting is a better fit.
We reconsider an alternative theory of QED with the photon as a massless vector Nambu–Goldstone boson and show that the underlying spontaneous Lorentz violation caused by the vector field vacuum ...expectation value, while being superficial in gauge invariant theory, becomes physically significant in QED with a tiny gauge non-invariance. This leads, through special dispersion relations appearing for charged fermions, to a new class of phenomena, which could be of distinctive observational interest in particle physics and astrophysics. They include a significant change in the GZK cutoff for UHE cosmic-ray nucleons, stability of high-energy pions and W bosons, a modification of nucleon beta decays, and some other ones.
The decay psi(2S) --> etaJ/psi is used to measure, for the first time, all prominent eta-meson branching fractions with the same experiment in the same dataset, thereby providing a consistent ...treatment of systematics across branching fractions. We present results for eta decays to gamma gamma, pi(+)pi(-)pi(0), 3pi(0), pi(+)pi(-)gamma and e(+)e(-)gamma, accounting for 99.9% of all eta decays. The precision of several of the branching fractions and their ratios is improved. Two channels, pi(+)pi(-)gamma and e(+)e(-)gamma, show results that differ at the level of three standard deviations from those previously determined.
We report here measurement of the cross section of e+e- → π+π-ψ ( 2S ) between 4.0 and 5.5 GeV, based on an analysis of initial state radiation events in a 980fb-1 data sample recorded with the Belle ...detector. The properties of the Y ( 4360 ) and Y ( 4660 ) states are determined. Fitting the mass spectrum of π+π-ψ ( 2S ) with two coherent Breit-Wigner functions, we discover two solutions with identical mass and width but different couplings to electron-positron pairs: MY ( 4360 ) = ( 4347±6±3 ) MeV / c2 , Γ Y ( 4360 ) = ( 103±9±5 ) MeV , MY ( 4660 ) = ( 4652±10±8 ) MeV / c2 , Γ Y ( 4660 ) = ( 68±11±1 ) MeV ; and B Y ( 4360 ) → π+π-ψ ( 2S ) · Γ Y ( 4360 ) e+e-= ( 10.9±0.6±0.7 ) eV and B Y ( 4660 ) → π+π-ψ ( 2S ) · Γ Y ( 4660 ) e+e-= ( 8.1±1.1±0.5 ) eV for one solution; or B Y ( 4360 ) → π+π-ψ ( 2S ) · Γ Y ( 4360 ) e+e-= ( 9.2±0.6±0.6 ) eV and B Y ( 4660 ) → π+π=ψ ( 2S ) · Γ Y ( 4660 ) e+e-= ( 2.0±0.3±0.2 ) eV for the other. Here, the first errors are statistical and the second systematic. Evidence for a charged charmoniumlike structure at 4.05GeV / c2 is observed in the π±ψ ( 2S ) intermediate state in the Y ( 4360 ) decays. decays.
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