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Proposal to study inelastic high energy proton-proton collisions in the diffractive region
Meson Decay Constants from Isospin Mass Splittings in the Quark Model
Decay constants of and mesons are estimated within the framework of a
heavy-quark approach using measured isospin mass splittings in the , ,
and states to isolate the electromagnetic hyperfine interaction between
quarks. The values MeV and MeV are
obtained. Only experimental errors are given; possible theoretical ambiguities,
and suggestions for reducing them, are noted.Comment: 7 pages, LaTeX, EFI-92-3
Chiral Perturbation Theory for SU(3) Breaking in Heavy Meson Systems
The SU(3) breaking effects due to light quark masses on heavy meson masses,
decay constants () and the form factor for semileptonic
transitions are formulated
in chiral perturbation theory, using a heavy meson effective Lagrangian and
expanding in inverse powers of the heavy meson mass. To leading order in this
expansion, the leading chiral logarithms and the required counterterms are
determined. At this level, a non-analytic correction to the mass splittings of
appears, similar the the one found in light baryons. The
correction to is roughly estimated to be of the order of
and, therefore, experimentally accessible, while the correction to the
form factor is likely to be substantially smaller. We explicitly check that the
heavy quark symmetry is preserved by the chiral loops.Comment: 21 page
Very light CP-odd scalar in the Two-Higgs-Doublet Model
We show that a general two-Higgs-doublet model (THDM) with a very light
CP-odd scalar (A) can be compatible with the rho parameter, Br(b --> s\gamma),
R_b, A_b, (g-2) of muon, Br(Upsilon --> A gamma), and the direct search via the
Yukawa process at LEP. For its mass around 0.2 GeV, the muon (g-2) and
Br(Upsilon --> A \gamma) data require tan(beta) to be about 1. Consequently, A
can behave like a fermiophobic CP-odd scalar and predominantly decay into a
photon pair ("gamma gamma"), which registers in detectors of high energy
collider experiments as a single photon signature when the momentum of A is
large. We compute the partial decay width of Z --> A A A and the production
rate of f \bar{f} --> Z A A --> Z +"gamma gamma", f^' {\bar f} --> W^{\pm} A A
--> W^\pm + "gamma gamma" and f \bar f --> H^+ H^- --> W^+ W^- A A --> W^+ W^-
+ "gamma gamma" at high energy colliders such as LEP, Tevatron, LHC, and future
Linear Colliders. Other production mechanisms of a light A, such as gg --> h
--> AA --> "gamma gamma", are also discussed.Comment: Some improvementes, references updated, 3 new figures, one new
appendix, abstract and conclusions unchaged. Version to appear in Physical
Review
Hidden Local Symmetry for Anomalous Processes with Isospin/SU(3) Breaking Effects
We show that isospin/SU(3) breaking terms can be introduced to the anomalous
VVP coupling in the hidden local symmetry scheme without changing
Wess-Zumino-Witten term in the low-energy limit. We make the analysis for
anomalous processes of 2-body and 3-body decays; radiative vector meson
decays(V \to P\gamma), conversion decays of photon into a lepton pair(V \to P
l^+ l^-) and hadronic anomalous decays(V \to PPP). The predictions successfully
reproduce all experimental data of anomalous decays. In particular, we predict
the decay widths of \rho^0 \to \pi^0 \gamma and \phi \to \eta' \gamma as 101
\pm 9 keV and 0.508 \pm 0.035 keV, respectively, which will be tested in the
DAFNE \phi-factory. Moreover, prediction is also made for \phi \to \pi^0 e^+
e^-, \rho \to 3\pi, K^* \to K \pi \pi and so on, for which only the
experimental upper bounds are available now.Comment: 19 pages, 4 tables, no figur
Signals for CPT and Lorentz Violation in Neutral-Meson Oscillations
Experimental signals for indirect CPT violation in the neutral-meson systems
are studied in the context of a general CPT- and Lorentz-violating
standard-model extension. In this explicit theory, some CPT observables depend
on the meson momentum and exhibit diurnal variations. The consequences for CPT
tests vary significantly with the specific experimental scenario. The wide
range of possible effects is illustrated for two types of CPT experiment
presently underway, one involving boosted uncorrelated kaons and the other
involving unboosted correlated kaon pairs.Comment: Accepted in Physical Review D, scheduled for December 1999 issu
Measurement of the K_L \to \pi\mu\nu form factor parameters with the KLOE detector
Using 328 pb^{-1}of data collected at DAFNE corresponding to 1.8
million decays, we have measured the form factor
parameters. The structure of the vector-current provides information
about the dynamics of the strong interaction; its knowledge is necessary for
evaluation of the phase-space integral required for measuring the CKM matrix
element and for testing lepton universality in kaon decays. Using a
new parametrization for the vector and scalar form factors, we find
=\pt(25.7\pm 0.6),-3, and =\pt(14.0\pm 2.1),-3,. Our
result for , together with recent lattice calculations of ,
and , satisfies the Callan-Trieman relatio
Phenomenology of Decays
Using the QCD sum rules technique we study several aspects of the
phenomenology of the b-flavoured strange meson . In particular, we
evaluate the mass of the particle, the leptonic constant and the form factors
of the decays , , . We also calculate, in the factorization approximation, a number of
two-body non leptonic decays.Comment: 19 pages, 2 figures (not included) available upon request, LaTex,
BARI-TH/93-139, UTS-DFT-93-1
A global fit to determine the pseudoscalar mixing angle and the gluonium content of the eta' meson
We update the values of the eta-eta' mixing angle and of the eta' gluonium
content by fitting our measurement R_phi = BR(phi to eta' gamma)/ BR(phi to eta
gamma) together with several vector meson radiative decays to pseudoscalars (V
to P gamma), pseudoscalar mesons radiative decays to vectors (P to V gamma) and
the eta' to gamma gamma, pi^0 to gamma gamma widths. From the fit we extract a
gluonium fraction of Z^2_G = 0.12 +- 0.04, the pseudoscalar mixing angle psi_P
= (40.4 +- 0.6) degree and the phi-omega mixing angle psi_V = (3.32 +- 0.09)
degree. Z^2_G and psi_P are fairly consistent with those previously published.
We also evaluate the impact on the eta' gluonium content determination of
future experimental improvements of the eta' branching ratios and decay width.Comment: 13 pages, 7 figures to submit to JHE
Provisional Agenda for the forty-ninth meeting of the Large Hadron Collider Committee to be held Wednesday and Thursday 29-30 November 2000
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