Search results for "Approx"
showing 10 items of 922 documents
Role of theN*(1535)resonance and theπ−p→KYamplitudes in the OZI forbiddenπN→ϕNreaction
2008
We study the $\ensuremath{\pi}N\ensuremath{\rightarrow}\ensuremath{\phi}N$ reaction close to the $\ensuremath{\phi}N$ threshold within the chiral unitary approach, by combining the ${\ensuremath{\pi}}^{\ensuremath{-}}p\ensuremath{\rightarrow}{K}^{+}{\ensuremath{\Sigma}}^{\ensuremath{-}},{\ensuremath{\pi}}^{\ensuremath{-}}p\ensuremath{\rightarrow}{K}^{0}{\ensuremath{\Sigma}}^{0}$, and ${\ensuremath{\pi}}^{\ensuremath{-}}p\ensuremath{\rightarrow}{K}^{0}\ensuremath{\Lambda}$ amplitudes with the coupling of \ensuremath{\phi} to the $K$ components of the final states of these reactions via quantum loops. We obtain good agreement with experiment when the dominant ${\ensuremath{\pi}}^{\ensuremath{…
Gamow-Teller transitions in theA=40isoquintet of relevance for neutrino captures inAr40
2014
Background: The Gamow-Teller response of $^{40}\mathrm{Ar}$ is important for the use of liquid argon as a medium for neutrino detection. An ambiguity about the Gamow-Teller strength for the excitation of ${1}^{+}$ states at 2290 and 2730 keV in $^{40}\mathrm{K}$ results in a significant uncertainty for neutrino capture rates. This ambiguity is caused by the large discrepancy observed between strengths extracted from $^{40}\mathrm{Ar}$($p$, $n$) charge-exchange data and the transition strengths for the analog transitions studied in the $\ensuremath{\beta}$ decay of $^{40}\mathrm{Ti}$.Purpose: This study was aimed at resolving the ambiguity between the results from the $^{40}\mathrm{Ar}$($p$,…
Measurements of cross section of e+e−→pp¯π0 at center-of-mass energies between 4.008 and 4.600 GeV
2017
Based on e(+)e(-) annihilation data samples collected with the BESIII detector at the BEPCII collider at 13 center-of-mass energies from 4.008 to 4.600 GeV, measurements of the Born cross section o ...
Electron capture decay of116Inand nuclear structure of doubleβdecays
1998
Quasiparticle-random-phase-approximation (QRPA) calculations of double $\ensuremath{\beta}$ decays have not been able to reproduce data in the $A=100$ system. We propose the $A=116$ system---because of its smaller deformation---as a simpler system to test QRPA calculations. We present results of two experiments we performed, which determine the electron-capture-decay branch of ${}^{116}\mathrm{In}$ to be $(2.27\ifmmode\pm\else\textpm\fi{}0.63)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2}%$, from which we deduce $\mathrm{log}{ft=4.39}_{\ensuremath{-}0.15}^{+0.10}$. We present QRPA calculations and compare their predictions to experimental data. Finally we use these calculations to…
Double beta decay versus cosmology: Majorana CP phases and nuclear matrix elements
2004
We discuss the relation between the absolute neutrino mass scale, the effective mass measured in neutrinoless double beta decay, and the Majorana CP phases. Emphasis is placed on estimating the upper bound on the nuclear matrix element entering calculations of the double beta decay half life. Consequently, one of the Majorana CP phases can be constrained when combining the claimed evidence for neutrinoless double beta decay with the neutrino mass bound from cosmology.
Total and inelastic cross sections at LHC ats=7 TeVand beyond
2011
We discuss expectations for the total and inelastic cross sections at LHC CM energies $\sqrt{s}=7\text{ }\text{ }\mathrm{TeV}$ and 14 TeV obtained in an eikonal minijet model augmented by soft gluon ${k}_{t}$-resummation, which we describe in some detail. We present a band of predictions which encompass recent LHC data and suggest that the inelastic cross section described by two-channel eikonal models include only uncorrelated processes. We show that this interpretation of the model is supported by the LHC data.
Magnetic dipole moment of theΔ+(1232)from theγp→γπ0preaction
2001
The $\ensuremath{\gamma}\stackrel{\ensuremath{\rightarrow}}{p}\ensuremath{\gamma}{\ensuremath{\pi}}^{0}p$ reaction in the $\ensuremath{\Delta}(1232)$-resonance region is investigated as a method to access the ${\ensuremath{\Delta}}^{+}(1232)$ magnetic dipole moment. The calculations are performed within the context of an effective Lagrangian model containing both the $\ensuremath{\Delta}$-resonant mechanism and a background of nonresonant contributions to the $\ensuremath{\gamma}\stackrel{\ensuremath{\rightarrow}}{p}\ensuremath{\gamma}{\ensuremath{\pi}}^{0}p$ reaction. Results are shown both for existing and forthcoming $\ensuremath{\gamma}\stackrel{\ensuremath{\rightarrow}}{p}\ensuremath{\…
Systematic study of neutrinoless double beta decay to excited 0+ states
2003
Abstract A systematic study of neutrinoless double beta (0 νββ ) decay to excited 0 + states, described as monopole-vibrational states or as composed of two collective quadrupole-phonon states, has been performed. Both double β − and double β + /EC decays have been analyzed within the framework of the multiple commutator model (MCM) by using a realistic nuclear many-body Hamiltonian and realistic mean-field single-particle bases. It is found that the associated 0 νββ -decay transitions are suppressed relative to the decay to the final ground state both by the available phase space and especially by the smallness of the involved transition matrix elements. For completeness, also the double β…
Observation of ${{e^+e^- \rightarrow D_s^+} \overline{ D}^{\bf (*)0} {K^-}}$ and study of the P -wave ${{D_s}}$ mesons
2018
Studies of $e^+e^- \to D_s^+ \overline{D}{}^{(*)0}K^-$ and the $P$-wave charmed-strange mesons are performed based on an $e^+e^-$ collision data sample corresponding to an integrated luminosity of 567 pb$^{-1}$ collected with the BESIII detector at $\sqrt{s}= 4.600$ GeV. The processes of $e^+e^-\to D_s^+ \overline{D}{*}^{0} K^-$ and $D_s^+ \overline{D}{}^{0} K^-$ are observed for the first time and are found to be dominated by the modes $D_s^+ D_{s1}(2536)^-$ and $D_s^+ D^*_{s2}(2573)^-$, respectively. The Born cross sections are measured to be $\sigma^{B}(e^+e^-\to D_s^+ \overline{D}{*}^{0} K^-) = (10.1\pm2.3\pm0.8) pb$ and $\sigma^{B}(e^+e^-\to D_s^+ \overline{D}{}^{0} K^-) = (19.4\pm2.3\…
Precise determination of resonance pole parameters through Pad\'e approximants
2014
In this work, we present a precise and model--independent method to extract resonance pole parameters from phase-shift scattering data. These parameters are defined from the associated poles in the second Riemann sheet, unfolded by the analytic continuation to the complex pole using Pad\'e approximants. Precise theoretical parameterizations of pion-pion scattering phase shifts based on once-- and twice-- subtracted dispersion relations are used as input, whose functional form allows us to show the benefit and accuracy of the method. In particular, we extract from these parametrization the pole positions of the $f_0(500)$ at $\sqrt{s}=(453\pm 15) - i(297 \pm 15)$ MeV, the $\rho(770)$ at $\sq…