相关论文: Sum rules for $e^+e^- \to W^+W^-$ helicity amplitu…

The existing calculations of the form factors describing the decay $B\to\rho e \nu$ from QCD sum rules have yielded conflicting results at small values of the invariant mass squared of the lepton pair. We demonstrate that the disagreement…

We calculate the independent helicity amplitudes in the decays $B \to K^* \ell^+ \ell^-$ and $B \to \rho \ell \nu_\ell$ in the so-called Large-Energy-Effective-Theory (LEET). Taking into account the dominant $O(\alpha_s)$ and SU(3)…

Electroweak interactions need three Nambu-Goldstone bosons to provide a mass to the W and the Z gauge bosons but they also need an ultra-violet moderator or new physics to unitarize the gauge boson scattering amplitudes. In this talk, I…

We employ the $B\to\pi$ form factors obtained from QCD light-cone sum rules and calculate the $B\to \pi \ell \nu_l$ width ($\ell=e,\mu$) in units of $1/|V_{ub}|^2$, integrated over the region of accessible momentum transfers, $0\leq q^2\leq…

We present a sum rule for Higgs fields in general representations under $SU(2)_L \times U(1)_Y$ that follows from the connection between the Higgs couplings and the mechanism that gives the electroweak bosons their masses, and at the same…

We study the process $e^-e^+\to \gamma H$, where $H$ represents $H_{SM}$, $h^0$ or $H^0$, which occurs at the one loop level in the standard model (SM) or in the minimal supersymmetric standard model (MSSM). We establish supersimple (sim)…

The scattering of longitudinally polarized electroweak bosons is likely to play an important role in the elucidation of the fundamental nature of the Electroweak Symmetry Breaking sector and in determining the Higgs interactions with this…

The $W$ boson mass is one of the most important electroweak precision observables for testing the Standard Model or its extensions. The very recent measured $W$ boson mass at CDF shows about $7\sigma$ deviations from the SM prediction,…

Recently the CDF Collaboration has announced a new precise measurement of the $W$-boson mass $M_W$ that deviates from the Standard Model (SM) prediction by $7\sigma$. The discrepancy in $M_W$ is about $\Delta_W\simeq70$ MeV and probably…

Higgs bosons - the amplitude modes - have been experimentally investigated in condensed matter for many years. An example is superfluid $^3$He-B, where the broken symmetry leads to 4 Goldstone modes and at least 14 Higgs modes, which are…

We investigate unitarity of $W^+W^-$ scattering in the context of theory space models of the form $U(1)\times {[SU(2)]}^N\times SU(2)_{N+1}$, which are broken down to $U(1)_{EM}$ by non-linear $\Sigma$ fields, without the presence of a…

We reconsider and update the QCD light-cone sum rules for $B\to \pi$ form factors. The gluon radiative corrections to the twist-2 and twist-3 terms in the correlation functions are calculated. The $\bar{MS}$ $b$-quark mass is employed,…

The $W$-boson pair production in $e^-e^-$ collisions with polarized beams is investigated. The helicity amplitudes are derived for general couplings and the conditions for a good high-energy behaviour of the cross-section are given. The…

We study the process $e^-e^+\to ZH$ where $H$ represents the standard model (SM) Higgs particle $H_{SM}$, or the MSSM ones $h^0$ and $H^0$. In each case, we compute the one-loop effects and establish very simple expressions, called…

In the context of the littlest Higgs$(LH)$ model, we study the process $ e^{+}e^{-}\to t\bar{t}$. We find that the new gauge bosons $Z_{H}$ and $B_{H}$ can produce significant correction effects on this process, which can be further…

The complete matrix elements for e^+ e^- -> 4f and e^+ e^- -> 4f + gamma are calculated in the Electroweak Standard Model for polarized massless fermions. The matrix elements for all final states are reduced to a few compact generic…

Applications of QCD sum rules to exclusive decays of heavy mesons are reviewed. In detail, we discuss the calculations of the B and $D$ decay constants, the heavy-to-light form factors $f^+(p^2)$ and $f^0(p^2)$, and the strong couplings…

We study perturbative unitarity and electroweak oblique corrections in the electroweak symmetry breaking models including an arbitrary number of neutral Higgs bosons. Requiring the perturbative unitarity of the high energy scattering…

We derive new QCD sum rules for $B\to D$ and $B\to D^*$ form factors. The underlying correlation functions are expanded near the light-cone in terms of $B$-meson distribution amplitudes defined in HQET, whereas the $c$-quark mass is kept…

The complete matrix elements for $e^+e^-\to b\bar bW^\pm H^\mp$ and $e^+e^-\to b\bar bH^+H^-$ are computed at tree-level within the Minimal Supersymmetric Standard Model. Rates of interest to phenomenological analyses at the Next Linear…