The e+ e- -> P1 P2 gamma processes close to the Phi peak: toward a model-independent analysis

We discuss the general decomposition and possible general parameterizations of the processes $e^+ e^- \to \gamma^* \to P_1 P_2 \gamma$, where $P_1 P_2=\pi^0 \pi^0$, $\pi^0\eta$, or $\pi^+\pi^-$, for $\sqrt{s}\approx M_\Phi$. Particular attention is devoted to the amplitude where the two pseudoscalar mesons are in a $J^{CP}= 0^{++}$ state, where we propose a general parameterization which should help to shed light on the nature of light scalar mesons.Comment: 12 pages, Late

Four-Quark Mesons in Non-leptonic B Decays--Could They Resolve Some Old Puzzles?

We point out that non-leptonic B decays driven by b-->ccbar s should provide a favourable environment for the production of hidden charm diquark-antidiquark bound states that have been suggested to explain the resonances with masses around 4 GeV recently observed by BaBar and BELLE. Studying their relative abundances in non-leptonic B decays can teach us novel lessons about their structure and the strong interactions. Through their decay into psi they can provide a natural explanation of the excess of B-->psi X observed for p_psi < 1 GeV. Other phenomenological consequences are mentioned as well.Comment: 6 pages, 2 figures, revte

Two-body non-leptonic decays on the lattice

We show that, under reasonable hypotheses, it is possible to study two-body non-leptonic weak decays in numerical simulations of lattice QCD. By assuming that final-state interactions are dominated by the nearby resonances and that the couplings of the resonances to the final particles are smooth functions of the external momenta, it is possible indeed to overcome the difficulties imposed by the Maiani-Testa no-go theorem and to extract the weak decay amplitudes, including their phases. Under the same assumptions, results can be obtained also for time-like form factors and quasi-elastic processes.Comment: 15 pages, 1 Postscript figur

Search for bbbˉbˉbb\bar{b}\bar{b} tetraquark decays in 4 muons, B+B−B^{+} B^{-}, B0Bˉ0B^0 \bar{B}^0 and Bs0Bˉs0B_s^0 \bar{B}_s^0 channels at LHC

We perform a quantitative analysis of the $bb\bar{b}\bar{b}$ tetraquark decays into hidden- and open-bottom mesons and calculate, for the first time, the $bb\bar{b}\bar{b}$ tetraquark total decay width. On the basis of our results, we propose the $bb\bar{b}\bar{b} \to B^{+} B^{-} (B^0 \bar{B}^0) (B_s^0 \bar{B}_s^0) \to l^{+} l^{-}+\text{X}$ decays as the most suitable channels to observe the $bb\bar{b}\bar{b}$ tetraquark states, since the calculated two-lepton cross section upper limit, $\simeq 39$ fb, is so large as to be potentially detectable with the 2018 LHCb sensitivity, paving the way to the observation of the $bb\bar{b}\bar{b}$ tetraquark in the future LHCb upgrade. The $4\mu$ signal for the ground state, $J^{PC}=0^{++}$, is likely to be too small even for the upgraded LHCb, but it may not be hopeless for the $J^{PC}=2^{++}$ fully-bottom state.Comment: 11 pages, 1 figur

The pi-N Sigma term - an evaluation using staggered fermions

A lattice calculation of the pi-N sigma term is described using dynamical staggered fermions. Preliminary results give a sea term comparable in magnitude to the valence term.Comment: Latex article, 3 pages. Contribution to the LAT93 Conference (Dallas, U.S.A., September 1993). HLRZ preprint 93-7

CP violation in K±→π0π0π±K^{\pm}\to\pi^0\pi^0\pi^{\pm} decay

CP violation leads to a difference between the parameters $g^+$ and $g^-$ describing the energy distributions of the charged pions produced in the $K^+ \to\pi^0 \pi^0 \pi^+$ and $K^- \to \pi^0\pi^0 \pi^-$ decays. We study the difference $(g^+ - g^-)$ as a function of the relative contributions from the QCD-penguin and the electroweak-penguin diagrams. We find that the combination of these contributions in $(g^+ - g^-)$ is very similar to the corresponding one defining the parameter $\epsilon'$ in the $K_L \to 2\pi$ decays. This observation allows a determination of the value of $(g^+ - g^-)$, using data on $\epsilon'$

Suppressed decay into open charm for the Y(4260) being an hybrid

We investigate the Y(4260) resonance recently discovered by the Babar collaboration. We propose the observation of its decay into J/psi pi pi and its non observation into open charm as a consequence of it being a charmonium hybrid state with a magnetic constituent gluon. We prove a selection rule forbidding its decay into two S-wave charmed mesons in any potential model. We suggest a generalisation of the selection rule based only on the heavy quark nature of the charm.Comment: 5 page

Model independent determination of the shape function for inclusive B decays and of the structure functions in DIS

We present a method to compute, by numerical simulations of lattice QCD, the inclusive semileptonic differential decay rates of heavy hadrons and the structure functions which occur in deep inelastic scattering. The method is based on first principles and does not require any model assumption. It allows the prediction of the differential rate in B semileptonic decays for values of the recoiling hadronic mass W ~ sqrt(M_B Lambda_QCD), which is in the relevant region to extract |V_ub| from the end-point of the lepton spectrum in inclusive decays.Comment: 16 pages, LaTeX fil

Optical production and detection of dark matter candidates

The PVLAS collaboration is at present running, at the Laboratori Nazionali di Legnaro of I.N.F.N., Padova, Italy, a very sensitive optical ellipsometer capable of measuring the small rotations or ellipticities which can be acquired by a linearly polarized laser beam propagating in vacuum through a transverse magnetic feld (vacuum magnetic birefringence). The apparatus will also be able to set new limits on mass and coupling constant of light scalar/pseudoscalar particles coupling to two photons by both producing and detecting the hypothetical particles. The axion, introduced to explain parity conservation in strong interactions, is an example of this class of particles, all of which are considered possible dark matter candidates. The PVLAS apparatus consists of a very high finesse (> 140000), 6.4 m long, Fabry-Perot cavity immersed in an intense dipolar magnetic field (~6.5 T). A linearly polarized laser beam is frequency locked to the cavity and analysed, using a heterodyne technique, for rotation and/or ellipticity acquired within the magnetic field.Comment: presented at "Frontier Detectors for Frontier Physics - 8th Pisa Meeting on Advanced Detectors - May 21-27, 2000" to appear in: Nucl.Instr. and Meth.