Search results for " Couplings"
showing 10 items of 30 documents
Pinning down the strength function for ordinary muon capture on 100Mo
2019
Ordinary muon capture (OMC) on 100Mo is studied both experimentally and theoretically in order to access the weak responses in wide energy and momentum regions. The OMC populates states in 100Nb up to some 50 MeV in excitation energy. For the first time the associated OMC strength function has been computed and compared with the obtained data. The present computations are performed using the Morita-Fujii formalism of OMC by extending the original formalism beyond the leading order. The participant nuclear wave functions are obtained in extended no-core single-particle model space using the spherical version of proton-neutron quasiparticle random-phase approximation (pnQRPA) with two-nucleon…
Higgs-Inflaton Mixing and Vacuum Stability
2019
The quartic and trilinear Higgs field couplings to an additional real scalar are renormalizable, gauge and Lorentz invariant. Thus, on general grounds, one expects such couplings between the Higgs and an inflaton in quantum field theory. In particular, the (often omitted) trilinear coupling is motivated by the need for reheating the Universe after inflation, whereby the inflaton decays into the Standard Model (SM) particles. Such a coupling necessarily leads to the Higgs-inflaton mixing, which could stabilize the electroweak vacuum by increasing the Higgs self-coupling. We find that the inflationary constraints on the trilinear coupling are weak such that the Higgs-inflaton mixing up to ord…
Single intermediate vector boson production in e(+)e(-) collisions at root s=183 and 189 GeV
2001
The cross sections for the production of single charged and neutral intermediate vector bosons were measured using integrated luminosities of 52 pb-1 and 154 pb-1 collected by the experiment at centre-of-mass energies of 182.6 GeV and 188.6 GeV, respectively. The cross sections for the reactions were determined in limited kinematic regions. The results found are in agreement with the Standard Model predictions for these channels. © 2001 Elsevier Science B.V.
Observation of s-Channel Production of Single Top Quarks at the Tevatron
2014
We report the first observation of single-top-quark production in the s channel through the combination of the CDF and D0 measurements of the cross section in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV. The data correspond to total integrated luminosities of up to 9.7fb-1 per experiment. The measured cross section is σs=1.29-0.24+0.26pb. The probability of observing a statistical fluctuation of the background to a cross section of the observed size or larger is 1.8×10-10, corresponding to a significance of 6.3 standard deviations for the presence of an s-channel contribution to the production of single-top quarks. © 2014 American Physical Society.
Search for Supersymmetry with Gauge-Mediated Breaking in Diphoton Events with Missing Transverse Energy at CDF II
2010
8 páginas, 3 figuras.-- PACS numbers: 12.60.Jv, 13.85.Rm, 13.85.Qk, 14.80.Ly.-- CDF Collaboration: et al.
Measurement of trilinear gauge couplings in e(+)e(-) collisions at 161 GeV and 172 GeV
1998
Trilinear gauge boson couplings are measured using data taken by DELPHI at 161 GeV and 172 GeV, Values for WWV couplings (V = Z,gamma) are determined from a study of the reactions e(+)e(-) --> W+W- and e(+)e(-) --> We nu, using differential distributions from the WW final state in which one W decays hadronically and the other leptonically, and total cross,section data from other channels, Limits are also derived on neutral ZV gamma couplings from an analysis of the reaction e(+)e(-) --> gamma + invisible particles. (C) 1998 Elsevier Science B.V.
Constraints on anomalous QGC's in $e^{+}e^{-}$ interactions from 183 to 209 GeV
2004
The acoplanar photon pairs produced in the reaction e+ e- --> nu nubar gamma gamma are analysed in the 700 inverse nanobarns of data collected by the ALEPH detector at centre-of-mass energies between 183 and 209 GeV. No deviation from the Standard Model predictions is seen in any of the distributions examined. The resulting 95% C.L. limits set on the anomalous QGC's, az_0, az_c, aw_0 and aw_c, are -0.012 GeV**-2 < az_0/Lambda**2 < +0.019 GeV**-2, -0.041 GeV**-2 < az_c/Lambda**2 < +0.044 GeV**-2, -0.060 GeV**-2 < aw_0/Lambda**2 < +0.055 GeV**-2, -0.099 GeV**-2 < aw_c/Lambda**2 < +0.093 GeV**-2, where Lambda is the energy scale of the new Physics responsible for the anomalous couplings.
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…
Perturbative Treatment of the Evolution Operator Associated with Raman Couplings
2006
A novel perturbative treatment of the time evolution operator of a quantum system is applied to the model describing a Raman-driven trapped ion in order to obtain a suitable 'effective model'. It is shown that the associated effective Hamiltonian describes the system dynamics up to a certain transformation which may be interpreted as a 'dynamical dressing' of the effective model.
Measurement of trilinear gauge boson couplings WWV, (V Z,gamma) in e(+)e(-) collisions at 189 GeV
2001
Measurements of the trilinear gauge boson couplings WWgamma and WWZ are presented using the data taken by DELPHI in 1998 at a centre-of-mass energy of 189 GeV and combined with DELPHI data at 183 GeV. Values are determined for Delta(g_1^Z) and Delta(kappa_gamma), the differences of the WWZ charge coupling and of the WWgamma dipole coupling from their Standard Model values, and for lambda_gamma, the WWgamma quadrupole coupling. A measurement of the magnetic dipole and electric quadrupole moment of the W is extracted from the results for Delta(kappa_gamma) and lambda_gamma. The study uses data from the final states jjlv, jjjj, lX, jjX and gammaX, where j represents a quark jet, l an identifie…