Search results for "PARTICLE PHYSICS"
showing 10 items of 6826 documents
Elastic pion scattering on the deuteron in a multiple scattering model
1996
Pion elastic scattering on deuterium is studied in the KMT multiple scattering approach developed in momentum space. Using a Paris wave function and the same methods and approximations as commonly used in pion scattering on heavier nuclei excellent agreement with differential cross section data is obtained for a wide range of pion energies. Only for $T_{\pi}>250$ MeV and very backward angles, discrepancies appear that are reminiscent of disagreements in pion scattering on $^3$He, $^3$H, and $^4$He. At low energies the second order corrections have been included. Polarization observables are studied in detail. While tensor analyzing powers are well reproduced, vector analyzing powers exhibit…
An Appearance-Like Reactor Experiment To Measure Ue3
2004
Conventional reactor neutrino experiments are dissapearance experiments, and thus have less sensitivity to small mixing angles than appearance experiments do. It has been recently shown that future reactor neutrino experiments consisiting of a near and far detector are competitive with first-generation superbeams in order to determine sin^2{2 theta_{13}} down to 10^{-2}. We show that by using the antineutrino-electron elastic scattering at the near detector around the configuration where dsigma^{bar{\nu}_e}/dT presents a dynamical zero, an appearance-like experiment can be simulated, with a sensitivity comparable to the one achieved with the inverse beta-decay reaction in the far detector. …
Backward spin polarizabilityγπof the proton
2002
Using the Mainz $48\mathrm{cm}\ensuremath{\emptyset}\ifmmode\times\else\texttimes\fi{}64\mathrm{cm}$ NaI(Tl) detector and the segmented G\"ottingen recoil detector SENECA in coincidence, Compton scattering by the proton at ${\ensuremath{\theta}}_{\ensuremath{\gamma}}^{\mathrm{lab}}=136\ifmmode^\circ\else\textdegree\fi{}$ has been measured at MAMI (Mainz) in the energy range from 200 to 470 MeV. The new data confirm the previous observation that there is a systematic discrepancy between MAMI and LEGS (Brookhaven) data leading to different spin polarizabilities ${\ensuremath{\gamma}}_{\ensuremath{\pi}}=\ensuremath{-}38.7\ifmmode\pm\else\textpm\fi{}1.8$ and $\ensuremath{-}27.2\ifmmode\pm\else\…
The influence of the nuclear medium on inclusive electron and neutrino scattering off nuclei
2007
We present a model for inclusive electron and neutrino scattering off nuclei paying special attention to the influence of in-medium effects on the quasi-elastic scattering and pion-production mechanisms. Our results for electron scattering off Oxygen are compared to experimental data at beam energies ranging from 0.7-1.5 GeV. The good description of electron scattering serves as a benchmark for neutrino scattering.
Probing nonstandard neutrino-electron interactions with solar and reactor neutrinos
2009
Most neutrino mass extensions of the standard electroweak model entail non-standard interactions which, in the low energy limit, can be parametrized in term of effective four-fermion operators $\nu_\alpha \nu_\beta \bar f f $. Typically of sub-weak strength, $\epsilon_{\alpha \beta} G_F$, these are characterized by dimensionless coupling parameters, $\epsilon_{\alpha \beta}$, which may be relatively sizeable in a wide class of schemes. Here we focus on non-universal (NU) flavor conserving couplings ($\alpha = \beta$) with electrons ($f = e$) and analyse their impact on the phenomenology of solar neutrinos. We consistently take into account their effect both at the level of propagation where…
Search for Effects Beyond the Born Approximation in Polarization Transfer Observables ine→pElastic Scattering
2011
Intensive theoretical and experimental efforts over the past decade have aimed at explaining the discrepancy between data for the proton electric to magnetic form factor ratio, $$G_{E}/G_{M}$$, obtained separately from cross section and polarization transfer measurements. One possible explanation for this difference is a two-photon-exchange (TPEX) contribution. In an effort to search for effects beyond the one-photon-exchange or Born approximation, we report measurements of polarization transfer observables in the elastic $$H(\vec{e},e'\vec{p})$$ reaction for three different beam energies at a fixed squared momentum transfer $Q^2 = 2.5$ GeV$^2$, spanning a wide range of the virtual photon p…
The real part of the elastic-scattering amplitude at the $$S\bar ppS$$ and predictions at LHC and SSCand predictions at LHC and SSC
1994
A precise measurement of\(\bar pp\) elastic scattering in the Coulomb strong-interaction interference region was performed at the CERN\(S\bar ppS\) Collider at a centre-of-mass energy of 541 GeV. The ratio of the real-to-imaginary part of the forward elastic-scattering amplitude was found to be ρ=0.135±0.015. The slope of the exponential fall-off of the strong-interaction part was also measured to beb=15.5±0.1 GeV−2. Using this new result, an overall fit to the data on the total cross-section and on the real part for\(\bar pp\) and pp was performed using dispersion relations. Numerical predictions are presented for total cross-sections at LHC and SSC energies.
Dynamical zeros in neutrino-electron elastic scattering at leading order
1994
We show the existence of dynamical zeros in the helicity amplitudes for neutrino-electron elastic scattering at lowest order in the standard theory. In particular, the $\lambda=1/2$ non-flip electron helicity amplitude in the electron antineutrino process vanishes for an incident neutrino energy $E_{\nu}=m_{e}/(4sin^{2}\theta_{W})$ and forward electrons (maximum recoil energy). The rest of helicity amplitudes show kinematical zeros in this configuration and therefore the cross section vanishes. Prospects to search for neutrino magnetic moment are discussed.
Microscopic calculation of the LSP detection rates for the 71Ga, 73Ge and 127I dark-matter detectors
2004
Abstract We have investigated the nuclear-structure details of the cross sections for the elastic scattering of Lightest Supersymmetric Particles (LSPs) from the promising dark-matter detectors 71 Ga, 73 Ge and 127 I. The associated LSP detection sensitivities have been obtained by a folding procedure for several recently proposed SUSY models with different scalar and axial-vector characteristics. For the nuclear problem, a realistic microscopic Hamiltonian has been used within realistic model spaces. The diagonalization of this Hamiltonian has been done by using the Microscopic Quasiparticle–Phonon Model (MQPM), suitable for description of spectroscopic properties of medium-heavy and heavy…
Electroluminescence TPCs at the thermal diffusion limit
2019
Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAM