Search results for "Interaction"
showing 10 items of 5710 documents
Experimental results on the electroweak interaction
1999
Recent results from the four experiments ALEPH, DELPHI, L3 and OPAL at the Large Electron-Positron collider, LEP at CERN, and by the SLD collaboration at the Stanford Linear Collider, SLC, are reviewed. Analyses from an integrated luminosity of about 150 pb− recorded by each experiment at LEP, taken at different centre-of-mass energies within ±3 GeV around the peak of the Z resonance during the years 1989 to 1995 are available now. Repeated accurate calibrations of the beam energy lead to precise measurements of the mass and of the total width of the Z boson. These results are complemented by measurements at the Z resonance with polarised beams at Stanford. First results from an integrated …
Top quark decay in the Aligned two-Higgs-doublet Model
2015
AbstractWe compute the one loop right and left anomalous tensor couplings (gR and gL, respectively) for the top quark, in the aligned two-Higgs-doublet model. They are the magnetic-like couplings in the most general parameterization of the tbW vertex. We find that the aligned two-Higgs doublet model, that includes as particular cases some of the most studied extensions of the Higgs sector, as Type I and II 2HDM, introduces new electroweak contributions and provides theoretical predictions that are very sensitive to both new scalar masses and the neutral scalar mixing angle. The model can account for new CP violation effects via the introduction of complex alignment parameters that have impo…
Combination of searches for anomalous top quark couplings with 5.4 fb−1 of pp¯ collisions
2012
We present measurements of the tWb coupling form factors using information from electroweak single top quark production and from the helicity of W bosons from top quark decays in t (t) over bar events. We set upper limits on anomalous tWb coupling form factors using data collected with the DO detector at the Tevatron p (p) over bar collider corresponding to an integrated luminosity of 5.4 fb(-1).
Semicontact three-body interaction for nuclear density functional theory
2015
International audience; To solve difficulties related to the use of nuclear density functional theory applied in its beyond-mean-field version, we introduce a semicontact three-body effective interaction. We show that this interaction is a good candidate to replace the widely used density-dependent effective interaction. The resulting new functionals are able to describe symmetric, neutron, polarized, and neutron polarized nuclear matter as well as the effective mass properties simultaneously.
Spectroscopy on the proton drip-line: Probing the structure dependence of isospin nonconserving interactions
2014
J. Henderson et al. ; 4 pags. ; 4 figs. ; PACS number(s): 21.10.Re, 21.60.Cs, 23.20.Lv, 27.50.+e
Hyperfine structure studies in the 6s 6p3P2-level of barium
1991
The hfs of the3P2 state of the 6s 6p configuration of atomic barium has been determined for137Ba, applying the collinear fast-beam laser spectroscopy. The data fill the last gap in the experimental information on low lying 6s2, 6s 6p, 6s 5d and 6p 5d configurations of this alcaline earth system. The results are analyzed in terms for the existing semi-empirical modified Breit-Wills theory (MBWT), working with two basic wave functions, as well as by an extension to six-component wave functions of inclusion of configuration interaction. The semi-empirical approaches lead to a consistent description of the different hyperfine structures; they are compared with the results from recent ab initio …
Weak-interaction and nuclear-structure aspects of nuclear double beta decay
1998
Abstract Weak-interaction and nuclear-structure aspects of double beta decay are reviewed. Starting from effective electroweak lagrangians, decay rates for the two-neutrino and neutrinoless modes of the nuclear double beta decay transitions are defined and second-order perturbative expressions for the nuclear decay amplitudes are given. Nuclear matrix elements of the relevant operators are presented, as extracted from data and from shell-model and QRPA calculations as well as from other theoretical approximations. The analysis is performed both for the two-neutrino and neutrinoless modes of the decay. The expressions for ground-state-to-ground-state and ground-state-to-excited-state transit…
Challenges for solid state detectors tracking detectors in nuclear physics experiments at FAIR
2007
The compelling scientific goals of future nuclear physics experiments demand significant advances in detector technology. Nuclear physics opportunities at future facility FAIR have never been so bright, but the detector challenges must be met. With the essential questions concerning nuclear structure and dynamics, nuclear astrophysics, limits of nuclear stability, tests of fundamental interactions and symmetries all being realistic targets of studies of exotic nuclei, detector development efforts are strongly motivated. Several examples of developments for future fixed target experiments as well as experiments at storage ring are outlined.
Electroweak effects in the extraction of the CKM angle γ from B→Dπ decays
2015
The angle γ of the standard CKM unitarity triangle can be determined from tree-level B-meson decays essentially without hadronic uncertainties. We calculate the second-order electroweak corrections for the B→Dπ modes and show that their impact on the determination of γ could be enhanced by an accidental cancellation of poorly known hadronic matrix elements. However, we do not expect the resulting shift in γ to exceed |δγDπ/γ|≲O(10−4).
Brownian dynamics simulations with hard-body interactions: Spherical particles
2012
A novel approach to account for hard-body interactions in (overdamped) Brownian dynamics simulations is proposed for systems with non-vanishing force fields. The scheme exploits the analytically known transition probability for a Brownian particle on a one-dimensional half-line. The motion of a Brownian particle is decomposed into a component that is affected by hard-body interactions and into components that are unaffected. The hard-body interactions are incorporated by replacing the affected component of motion by the evolution on a half-line. It is discussed under which circumstances this approach is justified. In particular, the algorithm is developed and formulated for systems with spa…