Lower limit for heavy muon mass obtained from the data of the CERN neutrino experiment

A lower limit for the heavy muon (heavy lepton omega′^? which can have the same lepton number as omega^? and ν_omega) mass M_μ′ > 1.8 GeV at 90% confidence level is obtained with the help of the bubble chamber “Gargamelle” data in the CERN neutrino experiment. This limit should not be confused with the known limit for an M⁺ (heavy lepton M⁺ which can have the same lepton number as μ^? and ν_μ).     

Search for invisible decay of the Upsilon(1S)

We report results of a search for the invisible decay of the Upsilon(1S) via the Upsilon(3S)-->pi+ pi- Upsilon(1S) transition using a data sample of 2.9 fb-1 at the Upsilon(3S) resonance. The data were collected with the Belle detector at the KEKB asymmetric-energy e+ e- collider. No signal is found, and an upper limit for the branching fraction at the 90% confidence level is determined to be B(Upsilon(1S)-->invisible)<2.5 x 10(-3).     

Determination of an upper limit of the mass of the muonic neutrino from the pion decay in flight

An experiment has been performed to determine an upper limit on m_νμ from pion decay in flight in the forward direction. The kinematical analysis and the inherent calibrations lead to the result: 〈m_νμ²〉 = ?0.14 ± 0.20 (MeV/c²)² (68% CL), (90% CL).     

Lower limit on radius as a function of mass for neutron stars

A model-independent limit on neutron star radius as a function of mass based only on well-accepted principles is derived. We discuss our limit in connection with a recent interpretation of x-ray pulsations from SAX J1808.4-3658 as indicating a strange-star candidate, and show that this object can also be a normal neutron star, though one whose central core has very high density. The most plausible high-density phase of hadronic matter, which is also expected to be very compressible, is quark matter. So an alternative to the strange star interpretation of SAX J1808.4-3658 is that it is a hybrid neutron star.     

Weak interactions of a light gravitino: A lower limit on the gravitino mass from the decay ψ→gravitino + antiphotino

The massive gravitino of spontaneously-broken locally supersymmetric theories may well be very light, leading to a mixing between weak and gravitational interactions. Particularly interesting is the photon coupling to a gravitino-antiphotino pair, with a vertex factor ($\text{κ/m}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext><mtext>\surd 6</mtext>}}\text{) γ}{}^{\mathrm{\mu }}\text{q}{}^2$: a one-photon exchange with ordinary fermions is equivalent to a local four-fermion interaction. From the upper limit on the decay ψ → gravitino + antiphotino we get a lower limit ～ 10^?8 eV/c² on the gravitino mass.     

New limit on time-reversal violation in beta decay

We report the results of an improved determination of the triple correlation DP·(p(e)×p(v)) that can be used to limit possible time-reversal invariance in the beta decay of polarized neutrons and constrain extensions to the standard model. Our result is D=[-0.96±1.89(stat)±1.01(sys)]×10(-4). The corresponding phase between gA and gV is ?AV=180.013°±0.028° (68% confidence level). This result represents the most sensitive measurement of D in nuclear β decay.     

New limit on the neutrinoless betabeta decay of 130Te

We report the present results of CUORICINO, a search for neutrinoless double-beta (0nu betabeta) decay of 130Te. The detector is an array of 62 TeO2 bolometers with a total active mass of 40.7 kg. The array is cooled by a dilution refrigerator shielded from environmental radioactivity and energetic neutrons, operated at approximately 8 mK in the Gran Sasso Underground Laboratory. No evidence for (0nu betabeta) decay was found and a new lower limit, T(1/2)(0nu) > or = 1.8 x 10(24) yr (90% C.L.) is set, corresponding to [m(nu)] < or = 0.2 to 1.1 eV, depending on the theoretical nuclear matrix elements used in the analysis.     

A new limit on the orthomuon mass

Results of the CDHS group NC/CC measurements are used to obtain the 10.3 GeV lower limit on the orthomuon mass.     

Unitarity limit on the gaugino-gravitino mass ratio

The imposition of tree-level unitarity at all energies upto the Planck scale on the amplitude for the scattering of two gauge bosons into two gravitinos is shown to put an upper bound on the ratio between gaugino and gravitino masses. The absolute masses of the lightest gauge singlet scalar and pseudoscalar bosons are also bounded from above.