Search results for "hadron"
showing 10 items of 3505 documents
Probing shapes of very neutron deficientZ≈82 nuclei using the recoil-decay tagging method
1997
The JYFL gas-filled recoil separator, RITU, combined with efficient Ge-detector arrays has been employed in in-beam γ-ray studies of very neutron-deficient nuclei close to theZ=82 shell. Gamma-rays from nuclei produced at the few μb cross-section level have been detected.
Λ polarization in associated K+–Λ electro-production
1999
Abstract The result of a feasibility study to measure the Λ polarization in associated K + – Λ electro-production is presented. This measurement was performed in the experimental Hall C at Jefferson Lab. The scattered electron was detected in the HMS spectrometer, and the electro-produced kaon and the proton from the Λ → pπ − decay were both detected in the SOS spectrometer. This quantity is very sensitive to the elementary p ( e , e ′ K ) Λ process and gives information on resonance production, and Regge exchange, among others. The result presented was measured at Q 2 =1.50 (GeV/c) 2 and cos θ Kγ CM =14°. The limits of the Λ polarization, with respect to the p γ × p K axis, were found to b…
The three-spectrometer setup for (e,e'x) coincidence experiments at the Mainz microtron MAMI
1995
A setup of three high-resolution magnetic spectrometers has been built up as the central facility for the precise determination of electron scattering cross sections in coincidence with hadrons. The operational experiencies with two of the spectrometers, A and B, demonstrate that both spectrometers exceed the specifications. With A and B, a series of ( e, e′x ) coincidence experiments were successfully performed. The third spectrometer, C, will be ready for operation in late autumn 1994.
Strange quark mass from τ decays
2001
7 páginas, 3 figuras, 3 tablas.-- Comunicación presentada en el 6º International Workshop on Tau Lepton Physics (Tau00) celebrado del 18 al 21 de Septiembre de 2000 en Victoria (Canada).
A new measurement of the branching ratio of K(S) → γ γ
2000
Abstract The decay rate of KS → γγ has been measured with the NA48 detector at the CERN SPS. A total of 149 KS → γγ events have been observed. The branching ratio is determined to be (2.58±0.36(stat)±0.22(sys))×10−6.
Absorptive effects inK+Λphotoproduction on nucleons and nuclei
1989
Incorporating final state correlation effects, we have reinvestigated the ..gamma.. /sup 1/H..-->..K/sup +/..lambda.. elementary process. Our model not only resolves the persisting trouble of the small KN..lambda.. coupling constant, but also yields agreement with cross section data at higher energies. Using our amplitudes, we calculate angular distributions for the reaction /sup 16/O(..gamma..,K/sup +/)/sub ..lambda..//sup 16/N . While the forward cross section increases with increasing energy, the total cross section is almost constant from E/sub ..gamma../ = 1.2 GeV through 2 GeV, suggesting that rather low photon energies hold promise for exploration of hypernuclear excitations.
Gamow-Teller Transitions Starting from T[sub z] = +3∕2 Nucleus [sup 47]Ti
2011
Gamow‐Teller (GT) transitions are mediated by the στ operator. Owing to its simplicity and also its spin‐isospin nature, GT transitions play key roles in the studies of nuclear structure as well as astro‐nuclear processes. In violent neutrino‐induced reactions at the core‐collapse stage of type II supernovae, Gamow‐Teller (GT) transitions starting from stable as well as unstable pf‐shell nuclei play important roles. We study GT transitions starting from 47Ti in a high‐resolution (3He,t) charge‐exchange reactions at 0° and at an intermediate incident energy of 140 MeV/nucleon at Research Center for Nuclear Physics (RCNP), Osaka. Individual GT transitions up to high excitations were observed.…
Electromagnetic production of polarization in hypernuclei.
1991
The formation of polarized hypernuclei through kaon photoproduction is investigated in a distorted-wave impulse approximation approach. The polarization depends strongly on the model used to describe the elementary process. For one particular model and certain well populated states the amount of polarization may reach up to 50%. We present cross sections and polarizations for kaon photoproducton on $^{16}\mathrm{O}$, $^{28}\mathrm{Si}$, $^{56}\mathrm{Fe}$, and $^{89}\mathrm{Y}$ and demonstrate the sensitivity of polarization to distortion and nonlocal effects. More information on the elementary process is needed before the feasibility of such measurements can be established.
Experimental study ofβ-delayed proton decay ofAl23for nucleosynthesis in novae
2011
The $\ensuremath{\beta}$-delayed $\ensuremath{\gamma}$ and proton decay of $^{23}\mathrm{Al}$ has been studied with an alternative detector setup at the focal plane of the momentum achromat recoil separator MARS at Texas A University. We could detect protons down to an energy of 200 keV and determine the corresponding branching ratios. Contrary to results of previous $\ensuremath{\beta}$-decay studies, no strong proton intensity from the decay of the isobaric analog state (IAS) of the $^{23}\mathrm{Al}$ ground state at ${E}_{x}=7803$ keV in $^{23}\mathrm{Mg}$ was observed. Instead we assign the observed low-energy group ${E}_{p,\mathrm{c}.\mathrm{m}.}=206$ keV to the decay from a state that…
Gamow-Teller Transitions Studied in ([sup 3]He, t) Reaction and Analogous β decay
2010
Due to the simplicity of the στ operator that causes Gamow‐Teller (GT) transitions, they are the most popular nuclear weak process in the Universe. The GT transitions in pf‐shell nuclei, for example, starting from stable Tz = +1 and proton‐rich Tz = +1 nuclei, where Tz = (N−Z)/2, play important roles in the supernova‐explosion or rp‐process nucleosynthesis. In the β‐decay study of pf‐shell nuclei, half‐lives can be measured rather accurately. On the other hand, in a high‐resolution (3He, t) charge‐exchange reaction at 0°, individual GT transitions up to high excitations can be studied. In order to derive reliable GT transition strengths B(GT), we present a unique analysis that combines the …