Search results for "Decay"
showing 10 items of 2087 documents
Neutrino Physics at the Turn of the Millenium
1999
Recent solar & atmospheric nu-data strongly indicate need for physics beyond the Standard Model. I review the ways of reconciling them in terms of 3-nu oscillations. Though not implied by data, bi-maximal nu-mixing models emerge as a possibility. SUSY with broken R-parity provides an attractive way to incorporate it, opening the possibility of testing nu-anomalies at high- energy colliders such as the LHC or at the upcoming long-baseline or nu- factory experiments. Reconciling, in addition, the LSND hint requires a fourth, light sterile neutrino, nus. The simplest are the most symmetric scenarios, in which 2 of the 4 neutrinos are maximally-mixed and lie at the LSND scale, while the oth…
On the description of non-unitary neutrino mixing
2015
28 pages.- 8 figures.- typos corrected.- modified bounds on non-unitarity parameters.- new figs 3 and 4
The beta-decay of95Rb and97Rb
1983
Theβ-decay of 377 ms95Rb and 168ms97Rb has been thoroughly investigated by means ofγ-ray, conversion electron andβ-delayed neutron spectroscopy. More than 97% of theβ-decay to particle-bound states has been placed in level schemes of95Sr and97Sr. High-resolution neutron spectroscopic studies have allowed to extend the knowledge of the excitation spectra up to 9 MeV, respectively 10 MeV. The density of neutron-unbound levels in95Sr and97Sr has been derived from peak stripping analyses of the neutron spectra. Beta-strength functions (S β(E)) have been investigated in detail. They indicate that Gamow-Tellerβ-decay of both precursors is dominated by nuclear structure. The discovered pronounced …
Study of thef2(1270),f2′(1525),K¯2*(1430),f0(1370)andf0(1710)production fromψ(nS)andϒ(nS)decays
2015
Based on previous studies that support the important role of the ${f}_{2}(1270)$, ${f}_{2}^{\ensuremath{'}}(1525)$, and ${\overline{K}}_{2}^{*}(1430)$ resonances in the $J/\ensuremath{\psi}[\ensuremath{\psi}(2S)]\ensuremath{\rightarrow}\ensuremath{\phi}(\ensuremath{\omega})VV$ decays, we make an analysis of the analogous decays of $\mathrm{\ensuremath{\Upsilon}}(1S)$ and $\mathrm{\ensuremath{\Upsilon}}(2S)$, taking into account recent experimental data. In addition, we study the $J/\ensuremath{\psi}$ and $\ensuremath{\psi}(2S)$ radiative decays and we also made predictions for the radiative decay of $\mathrm{\ensuremath{\Upsilon}}(1S)$ and $\mathrm{\ensuremath{\Upsilon}}(2S)$ into $\ensurem…
Measurement oftt¯production in theτ+jetstopology usingpp¯collisions ats=1.96 TeV
2010
We present a measurement of the t (t) over bar production cross section multiplied by the branching ratio to tau lepton decaying semihadronically (tau(h)) plus jets, sigma(p (p) over bar -> t (t) over bar + X) center dot BR(t (t) over bar -> tau(h) + jets), at a center of mass energy root s = 1.96 TeV using 1 fb(-1) of integrated luminosity collected with the D0 detector. Assuming a top quark mass of 170 GeV, we measure sigma(t (t) over bar) center dot BR tau h (+ j) = 0.60(-0.22)(+0.23)(stat)(-0.14)(+0.15)(syst) +/- 0.04(lumi) pb. In addition, we extract the t (t) over bar production cross section using the t (t) over bar -> tau(h) + jets topology, with the result sigma(t (t) over bar) = 6…
First simultaneous measurement of the top quark mass in thelepton+jetsand dilepton channels at CDF
2009
We present a measurement of the mass of the top quark using data corresponding to an integrated luminosity of 1.9 fb{sup -1} of pp collisions collected at {radical}(s)=1.96 TeV with the CDF II detector at Fermilab's Tevatron. This is the first measurement of the top quark mass using top-antitop pair candidate events in the lepton+jets and dilepton decay channels simultaneously. We reconstruct two observables in each channel and use a nonparametric kernel density estimation technique to derive two-dimensional probability density functions from simulated signal and background samples. The observables are the top quark mass and the invariant mass of two jets from the W decay in the lepton+jets…
Measurement of theCP-violating phaseβsJ/ψϕinBs0→J/ψϕdecays with the CDF II detector
2012
We present a measurement of the \CP-violating parameter \betas using approximately 6500 $$\BsJpsiPhi$$ decays reconstructed with the CDF\,II detector in a sample of $$p\bar p$$ collisions at $$\sqrt{s}=1.96$$ TeV corresponding to 5.2 fb$$^{-1}$$ integrated luminosity produced by the Tevatron Collider at Fermilab. We find the \CP-violating phase to be within the range $$\betas \in [0.02, 0.52] \cup [1.08, 1.55]$$ at 68% confidence level where the coverage property of the quoted interval is guaranteed using a frequentist statistical analysis. This result is in agreement with the standard model expectation at the level of about one Gaussian standard deviation. We consider the inclusion of a po…
Measurement of the fraction oftt¯production via gluon-gluon fusion inpp¯collisions ats=1.96 TeV
2009
We present a measurement of the ratio of the tt production cross section via gluon-gluon fusion to the total tt production cross section in pp collisions at √s=1.96 TeV at the Tevatron. Using a data sample with an integrated luminosity of 955 pb-1 recorded by the CDF II detector at Fermilab, we select events based on the tt decay to lepton+jets. Using an artificial neural network technique we discriminate between tt events produced via qq annihilation and gg fusion, and find Gf=σ(gg→tt )/σ(pp →tt )<0.33 at the 68% confidence level. This result is combined with a previous measurement to obtain the most stringent measurement of this quantity by CDF to date, Gf=0.07-0.07+0.15.
Measurement of thett¯production cross section with anin situcalibration ofb-jet identification efficiency
2011
A measurement of the top-quark pair-production cross section in ppbar collisions at sqrt{s}=1.96 TeV using data corresponding to an integrated luminosity of 1.12/fb collected with the Collider Detector at Fermilab is presented. Decays of top-quark pairs into the final states e nu + jets and mu nu + jets are selected, and the cross section and the b-jet identification efficiency are determined using a new measurement technique which requires that the measured cross sections with exactly one and multiple identified b-quarks from the top-quark decays agree. Assuming a top-quark mass of 175 GeV/c^2, a cross section of 8.5+/-0.6(stat.)+/-0.7(syst.) pb is measured.
Beta decay studies with total absorption spectroscopy and the Lucrecia spectrometer at ISOLDE
2017
26 pags., 21 figs., tab. -- Open Access funded by Creative Commons Atribution Licence 3.0