Search results for "coupling [Lambda(1520)]"
showing 10 items of 501 documents
Muon capture by a proton in heavy baryon chiral perturbation theory
1997
The matrix element for muon capture by a proton is calculated to O(p^3) within heavy baryon chiral perturbation theory using the new O(p^3) Lagrangian of Ecker and Mojzis. External nucleon fields are renormalized using the appropriate definition of the wave function renormalization factor Z_N. Our expression for Z_N differs somewhat from that found in existing literature, but is the one which is consistent with the Lagrangian we use and the one which ensures, within our approach, the nonrenormalization of the vector coupling as required by the conserved vector current. Expressions for the standard muon capture form factors are derived and compared to experimental data and we determine three…
νd→μ−Δ++nreaction and axial vectorN−Δcoupling
1999
The reaction $\ensuremath{\nu}\stackrel{\ensuremath{\rightarrow}}{d}{\ensuremath{\mu}}^{\ensuremath{-}}{\ensuremath{\Delta}}^{++}n$ is studied in the region of low ${q}^{2}$ to investigate the effect of deuteron structure and width of the $\ensuremath{\Delta}$ resonance on the differential cross section. The results are used to extract the axial vector $N\ensuremath{-}\ensuremath{\Delta}$ coupling ${C}_{5}^{A}$ from the experimental data on this reaction. The possibility to determine this coupling from electroweak interaction experiments with high intensity electron accelerators is discussed.
Search forWWandWZResonances Decaying to Electron, MissingET, and Two Jets inpp¯Collisions ats=1.96 TeV.
2009
We present a search for WW and WZ production in final states that contain a charged lepton (electron or muon) and at least two jets, produced in {radical}(s)=1.96 TeV pp collisions at the Fermilab Tevatron, using data corresponding to 1.2 fb{sup -1} of integrated luminosity collected with the CDF II detector. Diboson production in this decay channel has yet to be observed at hadron colliders due to the large single W plus jets background. An artificial neural network has been developed to increase signal sensitivity, as compared with an event selection based on conventional cuts. We set a 95% confidence level upper limit of {sigma}{sub WW}xBR(W{yields}l{nu}{sub l},W{yields}jets)+{sigma}{sub…
Elimination of unitarily nonequivalent vacua in supersymmetric grand unified theories by gravity
1983
Abstract In globally supersymmetric grand unified theories, there may be unitarily nonequivalent vacua which are not present in ordinary theories, reflecting the invariance of the Higgs potential under the complex extension of the gauge group. We show that such vacua are eliminated in the presence of N = 1 supergravity coupling, if local supersymmetry is broken and the costomological constant vanishes.
Two-pion Bose–Einstein correlations in central Pb–Pb collisions at sNN=2.76 TeV
2011
The first measurement of two-pion Bose-Einstein correlations in central Pb-Pb collisions at root(NN)-N-S = 2.76 TeV at the Large Hadron Collider is presented. We observe a growing trend with energy now not only for the longitudinal and the outward but also for the sideward pion source radius. The pion homogeneity volume and the decoupling time are significantly larger than those measured at RHIC. (C) 2010 CERN. Published by Elsevier B.V. All rights reserved.
Higgs pair signal enhanced in the 2HDM with two degenerate 125 GeV Higgs bosons
2015
We discuss a scenario of the type-II 2HDM in which the $b\bar{b}\gamma\gamma$ rate of the Higgs pair production is enhanced due to the two nearly degenerate 125 GeV Higgs bosons ($h$, $H$). Considering various theoretical and experimental constraints, we figure out the allowed ranges of the trilinear couplings of these two Higgs bosons and calculate the signal rate of $b\bar{b}\gamma\gamma$ from the productions of Higgs pairs ($hh$, $hH$, $HH$) at the LHC. We find that in the allowed parameter space some trilinear Higgs couplings can be larger than the SM value by an order and the production rate of $b\bar{b}\gamma\gamma$ can be greatly enhanced. We also consider a "decoupling" benchmark po…
Single inclusive particle production at high energy from HERA data to proton-nucleus collisions
2013
We study single inclusive hadron production in proton-proton and proton-nucleus collisions in the CGC framework. The parameters in the calculation are determined solely by standard nuclear geometry and by electron-proton deep inelastic scattering data, which is fit using the running coupling BK equation. We show that it is possible to obtain a good fit of the HERA inclusive cross section also without an anomalous dimension in the initial condition. We argue that one must consistently use the proton transverse area as measured by a high virtuality probe in DIS also for the single inclusive cross section in proton-proton and proton-nucleus collisions. We show that this leads to a midrapidity …
New interpretation for theDs2*(2573)and the prediction of novel exotic charmed mesons
2010
In this manuscript we study the vector-vector interaction within the hidden-gauge formalism in a coupled channel unitary approach. In the sector $C=1$, $S=1$, $J=2$ we get a pole in the $T$ matrix around 2572 MeV that we identify with the ${D}_{s2}^{*}(2573)$, coupling strongly to the ${D}^{*}{K}^{*}({D}_{s}^{*}\ensuremath{\phi}(\ensuremath{\omega}))$ channels. In addition we obtain resonances in other exotic sectors which have not been studied before such as $C=1$, $S=\ensuremath{-}1$, $C=2$, $S=0$ and $C=2$, $S=1$. These ``flavor-exotic'' states are interpreted as ${D}^{*}{\overline{K}}^{*}$, ${D}^{*}{D}^{*}$, and ${D}_{s}^{*}{D}^{*}$ molecular states but have not been observed yet. In to…
Non-decoupling of Heavy Neutrinos and Lepton Flavour Violation
1995
We consider a class of models predicting new heavy neutral fermionic states, whose mixing with the light neutrinos can be naturally significant and produce observable effects below the threshold for their production. We update the indirect limits on the flavour non-diagonal mixing parameters that can be derived from unitarity, and show that significant rates are in general expected for one-loop-induced rare processes due to the exchange of virtual heavy neutrinos, involving the violation of the muon and electron lepton numbers. In particular, the amplitudes for $\mu$--$e$ conversion in nuclei and for $\mu\to ee^+e^-$ show a non-decoupling quadratic dependence on the heavy neutrino mass $M$,…
Dependence of hadron spectra on decoupling temperature and resonance contributions
2003
Using equilibrium hydrodynamics with initial conditions for the energy and net baryon number densities from the perturbative QCD + saturation model, a good simultaneous description of the measured pion, kaon and (anti)proton spectra in central Au+Au collisions at $\sqrt s=130 A$GeV is found with a single decoupling temperature $\Tdec=150...160$ MeV. The interplay between the resonance content of the EoS and the development of the transverse flow leads to inverse slopes and $$ of hadrons which increase with decreasing $\Tdec$. The origin of this result is discussed.