Search results for "scattering [electron hadron]"
showing 10 items of 654 documents
Electron Angular Distribution in Laser-Assisted X-ray Photoeffect
1981
Calculations are reported of the differential cross section of the laser-assisted X-ray photoeffect from K shells showing that drastic changes occur in the shape of the ejected-electron angular distribution when laser photons are exchanged during the ionisation. This process appears well suited to the study of laser effects and multiphoton exchanges in laser-assisted atomic collisions.
Astrophysical S-factor for the $^{2}H(ρ,γ)^{3}$ He reaction at big-bang nucleosynthesis energies
2020
10th European Summer School on Experimental Nuclear Astrophysics , Catania, Italy, 16 Jun 2019 - 23 Jun 2019; The European physical journal / Web of Conferences 227, 02015 (2020). doi:10.1051/epjconf/202022702015
Threshold Neutral Pion Photoproduction on the Proton
2015
The neutral pion photoproduction on the proton near threshold has a very small scattering cross section when compared to the charged channels, which in ChPT is explained by strong cancellations between the lowest order pieces. Therefore it is very sensitive to higher-order corrections of chiral perturbation theory. We perform a fully covariant calculation up to chiral order p^3 and we investigate the effect of the inclusion of the Delta(1232) resonance as an explicit degree of freedom. We show that the convergence improves, leading to a much better agreement with data at a wide range of energies.
Top-quark mass measurements using jet rates at LHC
2013
This work presents a new method to measure the top-quark mass in hadronic collisions[1]. The method uses the sensitivity of the tt̄ + 1-jet production on the top-quark mass. In detail we study the ℛ distribution defined as the tt̄ + 1-jet normalized cross section differential in the invariant mass of the total system and calculated at NLO accuracy. We prove that the ℛ distribution has a high sensitivity to the top-quark mass. Furthermore we investigate and quantify the impact of the dominant theoretical and experimental uncertainties. The results obtained show, that the method has the potential to be competitive in precision with established approaches and allows a complementary measurement…
A sampling method for detecting buried objects using electromagnetic scattering
2005
We consider a simple (but fully three-dimensional) mathematical model for the electromagnetic exploration of buried, perfect electrically conducting objects within the soil underground. Moving an electric device parallel to the ground at constant height in order to generate a magnetic field, we measure the induced magnetic field within the device, and factor the underlying mathematics into a product of three operations which correspond to the primary excitation, some kind of reflection on the surface of the buried object(s) and the corresponding secondary excitation, respectively. Using this factorization we are able to give a justification of the so-called sampling method from inverse scat…
Electron Emission of Pt: Experimental Study and Comparison With Models in the Multipactor Energy Range
2016
Experimental data of secondary emission yield (SEY) and electron emission spectra of Pt under electron irradiation for normal incidence and primary energies lower than 1 keV are presented. Several relevant magnitudes, as total SEY, elastic backscattering probability, secondary emission spectrum, and backscattering coefficient, are given for different primary energies. These magnitudes are compared with theoretical or semiempirical formulas commonly used in the related literature.
Understanding seismic path biases and magmatic activity at Mount St Helens volcano before its 2004 eruption
2020
SUMMARY In volcanoes, topography, shallow heterogeneity and even shallow morphology can substantially modify seismic coda signals. Coda waves are an essential tool to monitor eruption dynamics and model volcanic structures jointly and independently from velocity anomalies: it is thus fundamental to test their spatial sensitivity to seismic path effects. Here, we apply the Multiple Lapse Time Window Analysis (MLTWA) to measure the relative importance of scattering attenuation vs absorption at Mount St Helens volcano before its 2004 eruption. The results show the characteristic dominance of scattering attenuation in volcanoes at lower frequencies (3–6 Hz), while absorption is the primary atte…
Investigating the nature of light scalar mesons with semileptonic decays of D mesons
2015
We study the semileptonic decays of $D_{s}^{+}$, $D^{+}$, and $D^{0}$ mesons into the light scalar mesons [$f_{0} (500)$, $K_{0}^{\ast} (800)$, $f_{0} (980)$, and $a_{0}(980)$] and the light vector mesons [$\rho (770)$, $\omega (782)$, $K^{\ast} (892)$, and $\phi (1020)$]. With the help of a chiral unitarity approach in coupled channels, we compute the branching fractions for scalar meson processes of the semileptonic $D$ decays in a simple way. Using current known values of the branching fractions, we make predictions for the branching fractions of the semileptonic decay modes with other scalar and vector mesons. Furthermore, we calculate the $\pi ^{+} \pi ^{-}$, $\pi \eta$, $\pi K$, and $…
Combined D0 measurements constraining theCP-violating phase and width difference in theBs0system
2007
We combine the D0 measurement of the width difference between the light and heavy B-s(0) mass eigenstates and of the CP-violating mixing phase determined from the time-dependent angular distributions in the B-s(0)-> J/psi phi decays along with the charge asymmetry in semileptonic decays also measured with the D0 detector. With the additional constraint from the world average of the flavor-specific B-s(0) lifetime, we obtain Delta Gamma(s)equivalent to(Gamma(L)-Gamma(H))=0.13 +/- 0.09 ps(-1) and vertical bar phi(s)vertical bar=0.70(-0.47)(+0.39) or Delta Gamma(s)=-0.13 +/- 0.09 ps(-1) and vertical bar phi(s)vertical bar=2.44(-0.39)(+0.47). The data sample corresponds to an integrated luminos…
Semileptonic decays ofBcmesons into charmonium states in a relativistic quark model
2005
We use the framework of a relativistic constituent quark model to study the semileptonic transitions of the ${B}_{c}$ meson into $(\overline{c}c)$ charmonium states where $(\overline{c}c)={\ensuremath{\eta}}_{c}(^{1}S_{0})$, $J/\ensuremath{\psi}(^{3}S_{1})$, ${\ensuremath{\chi}}_{c0}(^{3}P_{0})$, ${\ensuremath{\chi}}_{c1}(^{3}P_{1})$, ${h}_{c}(^{1}P_{1})$, ${\ensuremath{\chi}}_{c2}(^{3}P_{2})$, $\ensuremath{\psi}(^{3}D_{2})$. We compute the ${q}^{2}$ dependence of all relevant form factors and give predictions for their semileptonic ${B}_{c}$ decay modes including also their $\ensuremath{\tau}$ modes. We derive a formula for the polar angle distribution of the charged lepton in the $(l{\ens…