Search results for "DECAY"
showing 10 items of 2087 documents
γ-ray and decay spectroscopy of194,195,196At
2013
Excited states of ${}^{195}$At have been studied by means of in-beam $\ensuremath{\gamma}$-ray spectroscopy and the recoil-decay tagging technique. A strongly coupled rotational band feeding the $\ensuremath{\alpha}$-decaying $7/{2}^{\ensuremath{-}}$ state via unobserved transitions was identified. This band is presumably built on the oblate proton ${I}^{\ensuremath{\pi}}=13/{2}^{+}$ state. Confirming earlier measurements, $\ensuremath{\alpha}$ decays from the $1/{2}^{+}$ and $7/{2}^{\ensuremath{-}}$ states were observed. Additionally, an $E3$ branch competing with the $\ensuremath{\alpha}$ decay of the $7/{2}^{\ensuremath{-}}$ state was inferred. Also $\ensuremath{\alpha}$ decays of the od…
Nonlocality in superconducting microstructures
2001
We discuss experimental evidence of nonlocality in electron transport of small structures. It is shown that for superconductors reasonable agreement with experiment can be achieved by assuming exponential decay of the nonlocal interaction ∝ exp(—Lξ), where L is the distance between the interacting points and ξ is the correlation length. ξ is associated with the Ginzburg - Landau coherence length ξGL.
Improved measurement of the CKM angleγinB∓→D(*)K(*)∓decays with a Dalitz plot analysis ofDdecays toKS0π+π−andKS0K+K−
2008
We report on an improved measurement of the Cabibbo-Kobayashi-Maskawa CP-violating phase {gamma} through a Dalitz plot analysis of neutral D meson decays to K{sub s}{sup 0}{pi}{sup +}{pi}{sup -} and K{sub s}{sup 0}K{sup +}K{sup -} produced in the processes B{sup {-+}} {yields} DK{sup {-+}}, B{sup {-+}} {yields} D* K{sup {-+}} with D* {yields} D{pi}{sup 0}, D{gamma}, and B{sup {-+}} {yields} DK*{sup {-+}} with K8{sup {-+}} {yields} K{sub S}{sup 0}{pi}{sup {-+}}. Using a sample of 383 million B{bar B} pairs collected by the BABAR detector, we measure {gamma} = (76 {+-} 22 {+-} 5{+-} 5){sup o} (mod 180{sup o}), where the first error is statistical, the second is the experimental systematic unc…
Improved measurement of theB 0 andB + meson lifetimes
1996
The lifetimes of the B 0 and B + mesons have been measured with the Aleph detector at LEP, using approximately 3 million hadronic Z decays collected in the period 1991 1994. In the first of three methods, semileptonic decays of B 0 and B + mesons were partially reconstructed by identifying events containing a lepton with an associated D*- orbar D^0 meson. The second method used fully reconstructed B 0 and B + mesons. The third method, used to measure the B 0 lifetime, employed a partial reconstruction technique to identify B 0→ D*- π + X decays. The combined results are begin{gathered} tau _0 = 1.55 ± 0.06 ± 0.03 ps, \ tau _ + = 1.58 ± 0.09 ± 0.03 ps, \ tfrac{{tau _ + }}{{tau _0 }} = 1.03 ±…
Calibration of the NEXT-White detector using 83m Kr decays
2018
The NEXT-White (NEW) detector is currently the largest radio-pure high-pressure xenon gas time projection chamber with electroluminescent readout in the world. It has been operating at Laboratorio Subterr'aneo de Canfranc (LSC) since October 2016. This paper describes the calibrations performed using 83mKr decays during a long run taken from March to November 2017 (Run II). Krypton calibrations are used to correct for the finite drift-electron lifetime as well as for the dependence of the measured energy on the event transverse position which is caused by variations in solid angle coverage both for direct and reflected light and edge effects. After producing calibration maps to correct for …
Neutrinoless double beta decay with 82 SeF 6 and direct ion imaging
2018
We present a new neutrinoless double beta decay concept: the high pressure selenium hexafluoride gas time projection chamber. Combining techniques pioneered in high pressure xenon gas such as topological discrimination, with the high Q-value afforded by double beta decay isotope $^{82}$Se, a promising new detection technique is outlined. Lack of free electrons in SeF$_6$ mandates the use of an ion TPC. The microphysics of ion production and drift, which have many nuances, are explored. Background estimates are produced suggesting such a detector may achieve background indices of better than 1 count per ton per year in the region of interest at the 100~kg scale, and still better at the ton-s…
Direct Bound on the Total Decay Width of the Top Quark inpp¯Collisions ats=1.96 TeV
2009
We present the first direct experimental bound on the total decay width of the top quark, Gamma(t), using 955 pb(-1) of the Tevatron's p (p) over bar collisions recorded by the Collider Detector at Fermilab. We identify 253 top-antitop pair candidate events. The distribution of reconstructed top quark mass from these events is fitted to templates representing different values of the top quark width. Using a confidence interval based on likelihood-ratio ordering, we extract an upper limit at 95% C.L. of Gamma(t) < 13.1 GeV for an assumed top quark mass of 175 GeV/c(2).
Model-independent measurement of the W-boson helicity in top-quark decays at D0.
2008
Made available in DSpace on 2022-04-28T20:37:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-02-14 Science and Technology Facilities Council We present the first model-independent measurement of the helicity of W bosons produced in top quark decays, based on a 1fb-1 sample of candidate tt̄ events in the dilepton and lepton plus jets channels collected by the D0 detector at the Fermilab Tevatron pp̄ Collider. We reconstruct the angle θ* between the momenta of the down-type fermion and the top quark in the W boson rest frame for each top quark decay. A fit of the resulting cos θ* distribution finds that the fraction of longitudinal W bosons f0=0.425±0.166(stat)±0.102(syst) and the f…
Fission fragment angular distributions in the capture reactions 50Ti, 56Fe + 208Pb
2008
The analysis of %-ray mult ip l ic i t ies measured I in coincidence with capture fission events in reactions of 26Mg through 54Cr, 58Fe, and 64Ni with 208pb in terms of Ko and~eff revealed1 that the resulting values of ~ /~e f f were rather independent of for a given system and, in a compound nucleus picture, were more in agreement with the 'shape of the non-rotating saddle than with the actually expected rotating saddle I f non-compound systenmhave to be considered these values of ~/J~ff__ shapes. suggested at least that the captured systems near the turning point from the inward radial motion to symmetric fragmentation had reached a remarkable compactness.
Underlying A_4 Symmetry for the Neutrino Mass Matrix and the Quark Mixing Matrix
2002
The discrete non-Abelian symmetry $A_4$, valid at some high-energy scale, naturally leads to degenerate neutrino masses, without spoiling the hierarchy of charged-lepton masses. Realistic neutrino mass splittings and mixing angles (one of which is necessarily maximal and the other large) are then induced radiatively in the context of softly broken supersymmetry. The quark mixing matrix is also calculable in a similar way. The mixing parameter $U_{e3}$ is predicted to be imaginary, leading to maximal CP violation in neutrino oscillations. Neutrinoless double beta decay and $\tau \to \mu \gamma$ should be in the experimentally accessible range.