Heavy Flavor decays and light hadrons in the FOCUS experiment: recent results

Interpretation of D-meson decay-dynamics has revealed itself to be strongly dependent on our understanding of the light-meson sector. The interplay becomes particularly evident in Dalitz plot analyses to study physics within and beyond the Standard Model. Experience and results from FOCUS are presented and discussed. A brief update of the pentaquark search in the experiment is also reported.Comment: 10 pages,6 figures, Invited talk presented at SCADRON 70 (Workshop on Scalar Mesons), Lisbon 11-16 Feb 200

Two-photon decay of a light scalar quark-antiquark state

The two-photon decay of a light scalar quarkonium is evaluated in a local and a nonlocal approaches. It is shown that the two-photon decay, driven by a triangle quark-loop diagram, is smaller than 1 keV for a mass below 0.7 GeV.Comment: Presented at the workshop SCADRON 70 "Scalar Mesons and Related Topics" February 11-16, 2008, at IST in Lisbon, Portugal. 6 pages, 2 figure

Searching for the Scalar Glueball

Existence of gluonic resonances is among the early expectations of QCD. Today, QCD calculations predict the lightest glueball to be a scalar state with mass within a range of about 900-1700 MeV but there is no consensus about its experimental evidence. In a re-analysis of the phase shifts for pi pi scattering up to 1800 MeV where such states should show up we find the broad resonance f_0(600)/\sigma contributing to the full mass range and the narrow f_0(980) and f_0(1500) but no evidence for f_0(1370). Phenomenological arguments for the broad state to be a glueball are recalled. It is argued that the large radiative width of f_0(600)/\sigma reported recently is not in contradiction to this hypothesis but is mainly due to pi pi rescattering. The small ``direct'' radiative component is consistent with QCD sum rule predictions for the light glueball.Comment: 6 pages, 1 figure, Contribution to the Proceedings of the Workshop on Scalar Mesons and Related Topics Honoring Michael D. Scadron's 70th Birthday, 11-16 February 2008, Lisbon, Portuga

Spectrum of Higgsonium in the SM and beyond

Using the formalism of Bethe-Salpeter equation (BSE) the Higgsonium bound state is studied. The condition for formation of Higgsonium bound states are discussed in SM and in the simple extension of.Comment: 7 pages, talk presented at SCADRON 70, Workshop on Scalar Mesons and Related Topics, February 2008, Lisbo

Charmed Scalar Resonances

It is pointed out that assigning D_{s0}^+(2317) to an iso-triplet tetra-quark meson is favored by experiments. It also is discussed why its neutral and doubly charged partners have never been observed in inclusive e^+e^- annihilation. To search for them, hadronic weak decays of B mesons would be better, and their production rates, Br(B_u^+ -> D^-D_{s0}^{++}(2317)) and Br(B_d^0 ->antiD^0D_{s0}^{0}(2317)), would be around 10^{-3}.Comment: 4 pages, 1 figure, talk given at SCADON7

Simulations of light scalar mesons on the lattice and related difficulties

I review the lattice simulations of light scalar mesons with quark-antiquark and tetraquark interpolating fields. Several difficulties which complicate the extraction of scalar meson masses from the scalar correlators are pointed out. One of the major difficulties is the presence of the two-pseudoscalar scattering states, which often dominate the correlator at light quark masses. In the simulations with unphysical approximations such scattering contributions are even more disturbing since they are often large and sometimes negative. Techniques which allow extraction of scalar meson masses in presence of scattering states are listed. Preliminary results of various lattice collaborations are presented.Comment: Talk presented at workshop "Scalar mesons and Related Topics" (SCADRON70), Lisbon, Portugal, February 200

Scalar mesons and polarizability of the nucleon

It is shown that the scalar mesons $\sigma$, $f_0(980)$ and $a_0(980)$ as $t$-channel exchanges quantitatively solve the problem of diamagnetism and give an explanation of the large missing part of the electric polarizability $\alpha$ showing up when only the pion cloud is taken into account. The electric polarizability of the proton $\alpha_p$ confirms a two-photon width of the $\sigma$ meson of $\Gamma_{\sigma\gamma\gamma}=(2.58\pm 0.26)$ keV

Resonance sum rules from large NCN_C and partial wave dispersive analysis

Combining large $N_C$ techniques and partial wave dispersion theory to analyze the $\pi\pi$ scattering, without relying on any explicit resonance lagrangian, some interesting results are derived: (a) a general KSRF relation including the scalar meson contribution; (b) a new relation between resonance couplings, with which we have made an intensive analysis in several specific models; (c) low energy constants in chiral perturbation theory related with $\pi\pi$ scattering in terms of the mass and decay width of resonances.Comment: 4 pages, contribution to the Workshop on "Scalar meson and Related topics" (Scadron 70), during Feb 11-16, 2008, at IST, Lisbon, Portuga

0++0^{++} Resonances Observed at BES

In last 10 years, $0^{++}$ resonances have been observed and studied at BES in many processes, such as $J/\psi\to\gamma\pi^+\pi^-\pi^+\pi^-$, $\gamma\pi^+\pi^-$, $\gamma\pi^0\pi^0$, $\gamma K^+K^-$, $\gamma K_SK_S$, $\gamma\omega\phi$, $\omega\pi^+\pi^-$, $\omega K^+K^-$, $\phi\pi^+\pi^-$, $\phi K^+K^-$, $\psi(2S)\to J/\psi\pi^+\pi^-$, $\chi_{c0}\to\pi^+\pi^-K^+K^-$, $\pi^+\pi^-\pi^+\pi^-$ etc.. The results on $0^{++}$ resonances observed at BES are reviewed.Comment: Plenary talk at SCADRON70, Lisbon, Feb. 200

New (and Old) Perspectives on Higgs Physics

Old and new ideas regarding Higgs physics are reviewed. We first summarize the quadratic divergence / hierarchy problem which strongly suggests that the SM Higgs sector will be supplemented by new physics at high scales. We next consider means for delaying the hierarchy problem of the SM Higgs sector to unexpectedly high scales. We then outline the properties of the most ideal Higgs boson. The main advantages of a supersymmetric solution to the high scale problems are summarized and the reasons for preferring the next-to-minimal supersymmetric model over the minimal supersymmetric model in order to achieve an ideal Higgs are emphasized. This leads us to the strongly motivated scenario in which there is a Higgs $h$ with SM-like $WW,ZZ$ couplings and \mh\sim 100\gev that decays via $h\to aa$ with $m_a2m_\tau$ is preferred, implying $a\to \tau^+ \tau^-$. The means for detecting an $h\to aa\to 4\tau$ signal are then discussed. Some final cautionary and concluding remarks are given.Comment: 15 pages, 9 figure