Search results for "angular distribution"
showing 10 items of 89 documents
Elastische Streuung langsamer Elektronen an einem Bi-Atomstrahl
1968
The angular distribution of electrons elastically scattered by bismuth atoms has been investigated in the angular range from 30 to 155° and with electron energies between 5 and 1200 eV. Theoretical data, which are available for energies above 100 eV, are in good agreement with experiment.
Conceptual design and performance study for the first implementation of AGATA at the in-flight RIB facility of GSI
2012
Abstract The main objective of the Advanced GAmma Tracking Array (AGATA) is the investigation of the structure of exotic nuclei at the new generation of RIB facilities. As part of the preparatory phase for FAIR-NUSTAR, AGATA is going to be installed at the FRS fragmentation facility of the GSI centre for an experimental campaign to be performed in 2012 and 2013. Owing to its γ - ray tracking capabilities and the envisaged enhancement in resolving power, a series of in-flight γ - ray spectroscopy experiments are being planned. The present work describes the conceptual design of this first implementation of AGATA at GSI-FRS, and provides information about the expected performance figures. Acc…
Antiproton-proton annihilation at rest into KKπ0π0
1997
Abstract The annihilation channel p p →K + K − π 0 in liquid hydrogen at rest has been studied with the Crystal Barrel detector at LEAR. The measured branching ratio is: BR ( p p → K + K − π 0 )=(2.37±0.15)×10 −3 . A partial wave analysis shows that this reaction is dominated by the π (K K ) S , K K ∗ (892) and π φ (1020) intermediate states. Weak signals are observed for π a 2 (1320), π f 2 (1270), π f 2 ′(1525) and K(Kπ) S . A satisfactory description of the Dalitz plot requires the introduction of π (K K ) P intermediate states with at least one pole.
Winkelverteilungen elastisch an Edelgas-Atomstrahlen gestreuter Elektronen; Spinpolarisation eines an Argon gestreuten 40 eV-Elektronenstrahls
1967
The angular distribution of electrons scattered elastically by rare-gas atomic beams (He, Ne, Ar, Kr, Xe) has been investigated over the angular range from 20° to 155° and with electron energies between 5 eV and 1000 eV. The results are compared with theory. Only for energies above 300 eV the agreement is good. The angular dependence of polarization P(Θ) of electrons, elastically scattered by a beam of argon atoms, is measured in a double scattering experiment for an electron energy of 40 eV. Maximum degree of polarization measured isP=12.5% ± 2.5%.
Single-step link from yrast SD band in 143Eu
1997
A discrete γ-ray transition from the yrast SD band to the region of near-yrast discrete normal-deformed states has been identified in 143Eu. It has an energy of 3360.6 keV and an intensity corresponding to 3.2% of the full intensity of the SD band and feeds a nearly-spherical state above spin 352(+) and Ex=4947 keV. This agrees well with the picture of the decay out of the SD band gained previously from two-step links. The angular distribution analysis favours a stretched dipole character for the transition. Due to the complicated structure of the level scheme in the region of interest it has not been possible to place the transition exactly.
Measurement of the two neutrino double beta decay half-life of Zr-96 with the NEMO-3 detector
2010
Using 9.4 g of Zr-96 and 1221 days of data from the NEMO-3 detector corresponding to 0.031 kg yr, the obtained 2vbb decay half-life measurement is [2.35 +/- 0.14(stat) +/- 0.16(syst)] x 10^19 yr. Different characteristics of the final state electrons have been studied, such as the energy sum, individual electron energy, and angular distribution. The 2v nuclear matrix element is extracted using the measured 2vbb half-life and is 0.049 +/- 0.002. Constraints on 0vbb decay have also been set.
Measurements of branching fractions andCPasymmetries and studies of angular distributions forB→ϕϕKdecays
2011
We present branching fraction and CP asymmetry measurements as well as angular studies of B to phi phi K decays using 464 x 10^6 BBbar events collected by the BaBar experiment. The branching fractions are measured in the phi phi invariant mass range below the eta_c resonance (m_phiphi <2.85 GeV). We find B(B+ to phi phi K+) = (5.6 +/- 0.5 +/- 0.3) x 10^-6 and B(B0 to phi phi K0) = (4.5 +/- 0.8 +/- 0.3) x 10^-6, where the first uncertaintiy is statistical and the second systematic. The measured direct CP asymmetries for the B+- decays are A_CP = -0.10 +/- 0.08 +/- 0.02 below the eta_c threshold and A_CP = 0.09 +/- 0.10 +?- 0.02 in the eta_c resonance region (m_phiphi in [2.94,3.02] GeV). Ang…
Model-independent confirmation of theZ(4430)−state
2015
The decay $B^0\to \psi(2S) K^+\pi^-$ is analyzed using $\rm 3~fb^{-1}$ of $pp$ collision data collected with the LHCb detector. A model-independent description of the $\psi(2S) \pi$ mass spectrum is obtained, using as input the $K\pi$ mass spectrum and angular distribution derived directly from data, without requiring a theoretical description of resonance shapes or their interference. The hypothesis that the $\psi(2S)\pi$ mass spectrum can be described in terms of $K\pi$ reflections alone is rejected with more than 8$\sigma$ significance. This provides confirmation, in a model-independent way, of the need for an additional resonant component in the mass region of the $Z(4430)^-$ exotic sta…
Charged current weak electroproduction of the Delta resonance
1998
We study the weak production of $\ensuremath{\Delta}$ (i.e., ${e}^{\ensuremath{-}}+\stackrel{\ensuremath{\rightarrow}}{p}{\ensuremath{\Delta}}^{0}+{\ensuremath{\nu}}_{e}$ and ${e}^{+}+\stackrel{\ensuremath{\rightarrow}}{p}{\ensuremath{\Delta}}^{++}+{\overline{\ensuremath{\nu}}}_{e})$ in the intermediate energy range corresponding to the Mainz and TJNAF electron accelerators. The differential cross sections $\ensuremath{\sigma}(\ensuremath{\theta})$ are found to be of the order of ${10}^{\ensuremath{-}39}$ cm${}^{2}$/sr, over a range of angles which increases with energy. The possibility of observing these reactions with the high luminosities available at these accelerators, and studying the…
Study ofe+e−→pp¯via initial-state radiation atBABAR
2013
The e{sup +}e{sup -}{yields}pp cross section is determined over a range of pp masses, from threshold to 4.5 GeV/c{sup 2}, by studying the e{sup +}e{sup -}{yields}pp{gamma} process. The data set corresponds to an integrated luminosity of 232 fb{sup -1}, collected with the BABAR detector at the PEP-II storage ring, at an e{sup +}e{sup -} center-of-mass energy of 10.6 GeV. The mass dependence of the ratio of electric and magnetic form factors, G{sub E}/G{sub M}, is measured for pp masses below 3 GeV/c{sup 2}; its value is found to be significantly larger than 1 for masses up to 2.2 GeV/c{sup 2}. We also measure J/{psi}{yields}pp and {psi}(2S){yields}pp branching fractions and set an upper limi…