Search results for "decay"
showing 10 items of 2087 documents
Evidence ofB+→τ+νdecays with hadronicBtags
2013
We present a search for the decay B+→τ+ν using 467.8×10^6 BB pairs collected at the Υ(4S) resonance with the BABAR detector at the SLAC PEP-II B-Factory. We select a sample of events with one completely reconstructed B- in the hadronic decay mode (B-→D(*)0X- and B-→J/ψX-). We examine the rest of the event to search for a B+→τ+ν decay. We identify the τ+ lepton in the following modes: τ+→e+νν , τ+→μ+νν , τ+→π+ν and τ+→ρ+ν . We find an excess of events with respect to the expected background, which excludes the null signal hypothesis at the level of 3.8σ (including systematic uncertainties) and corresponds to a branching fraction value of B(B+→τ+ν)=(1.83_(-0.49)^(+0.53)(stat)±0.24(syst))×10^(…
Measurement of the form factors in the decayD+→ωe+νeand search for the decayD+→ϕe+νe
2015
Using 2.92 fb(-1) of electron-positron annihilation data collected at a center-of-mass energy of root s = 3.773 GeV with the BESIII detector, we present an improved measurement of the branching fra ...
B-physics results from LEP
1996
Abstract The LEP collider continues to improve our knowledge and understanding of B-physics. Recent results are presented in the areas of B-hadron lifetimes, BB oscillations, B-spectroscopy and rare B-decays.
Fermion masses and the UV cutoff of the minimal realistic SU(5)
2006
We investigate the predictions for fermion masses in the minimal realistic non-supersymmetric SU(5) model with the Standard Model matter content. The possibility to achieve b-\tau unification is studied taking into account all relevant effects. In addition, we show how to establish an upper bound on the ultraviolet cutoff \Lambda of the theory which is compatible with the Yukawa couplings at the grand unified scale and proton decay. We find \Lambda \simeq 10^{17} GeV, to be considered a conservative upper bound on the cutoff. We also provide up-to-date values of all the fermions masses at the electroweak scale.
Seesaw scale, unification, and proton decay
2018
We investigate a simple realistic grand unified theory based on the $SU(5)$ gauge symmetry which predicts an upper bound on the proton decay lifetime for the channels $p \to K^+ \bar{\nu}$ and $p \to \pi^+ \bar{\nu}$, i.e. $\tau (p \to K^+ \bar{\nu}) \lesssim 3.4 \times 10^{35}$ and $\tau (p \to \pi^+ \bar{\nu}) \lesssim 1.7 \times 10^{34}$ years, respectively. In this context, the neutrino masses are generated through the type I and type III seesaw mechanisms, and one predicts that the field responsible for type III seesaw must be light with a mass below 500 TeV. We discuss the testability of this theory at current and future proton decay experiments.
WMAPing the Universe: Supersymmetry, Dark Matter, Dark Energy, Proton Decay and Collider Physics
2003
In this review we discuss constraints on minimal supersymmetric models of particle physics implied by the recent astrophysical observations of WMAP. Although the prospects of detecting supersymmetry increase and 90 percent of the available MSSM parameter space can safely be reached by the sensitivity of future colliders, nevertheless we pay particular emphasis on discussing regions of the appropriate phase diagrams, which -if realized - would imply that detection of supersymmetry, at least in the context of minimal models, could be out of colliders reach. We also discuss the importance of a precise determination of the radiative corrections to the muon anomalous magnetic moment, both theore…
Nuclear matrix elements for double beta decay in the QRPA approach: a critical review
2009
The calculation of nuclear matrix elements (NME) for double beta decay transitions (DBD) relies upon several approximations. The purpose of this note is to review some of these approximations, and their impact upon the NME. We shall present our results, which have been obtained in the framework of the proton-neutron quasiparticle random phase approximation (pnQRPA), and we shall focus on short range correlations, pairing, and symmetry effects.
Beta decay and isomer spectroscopy in the 132Sn region: New results from EURICA
2013
A. Jungclaus et al.; XX International School on Nuclear Physics, Neutron Physics and Applications (Varna2013); Open Access. 4 pags.; 1 fig.
β-decay measurements ofA≃ 70 − 110 r-process nuclei at the National Superconducting Cyclotron Laboratory
2011
The present paper reports on several r-process motivated β-decay experiments undertaken at the National Superconducting Cyclotron Laboratory. β-decay half-lives and β-delayed neutron-emission probabilities were measured for nuclei around the r-process A = 70–80 and A = 90 – 110 mass regions. The data are discussed on the basis of quasi-random phase approximation calculations. The emphasis is made on the impact of these data upon calculations of r-process abundances.
Neutrino mass, neutrinoless double electron capture and rare beta decays
2010
We present results of our theoretical calculations on three nuclei of interest from the neutrino-physics point of view: Firstly, we present the second-forbidden decay branch of 115In with the ultra-low Q value and theoretical open questions related to such decays. Secondly, we have calculated estimates for the half-lives of the single-beta decay channels of 96Zr and concluded that the possible contamination from those to the geochemical measurements of 96Zr double-beta-decay half-life is rather small. Thirdly, we have taken a look at the neutrinoless resonance double-electron-capture decay of 112Sn in the light of recent JYFLTRAP Q value measurements and discovered that the badly fulfilled …