No abstract available

No abstract available

[en] The shift of the p-wave D_s meson mass due to coupling to the DK channel is calculated without fitting parameters using the chiral Lagrangian. As a result the original Q(bar q) mass 2.490 MeV generically calculated in the relativistic quark models is shifted down to the experimental value 2317 MeV. With the same Lagrangian the shift of the radial excited 1^-1 level is much smaller, while the total width Γ > 100 MeV and the width ratio is in contradiction with the D*(2632) state observed by SELEX group

[en] The authors report a measurement of the CP-violation parameter sin2β with B⁰ -> J/φK_S⁰ decays in which the J/ψ decays to hadrons. With a sample of 88 million Bbar B events collected by the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC, they reconstruct 100 +- 17 such events, with J/ψ -> π⁺π^-π⁰ being the most prevalent, and measure sin 2β= 1.56+-0.42(stat.)+-0.21(syst.)

[en] We compute the graviton-induced corrections to the trajectory of a classical test particle. We show that the motion of the test particle is governed by an effective action given by the expectation value (with respect to the graviton state) of the classical action. We analyze the quantum corrected equations of motion for the test particle in two particular backgrounds: a Robertson Walker spacetime and a (2+1)-dimensional spacetime with rotational symmetry. In both cases we show that the quantum corrected trajectory is not a geodesic of the background metric. copyright 1999 The American Physical Society

[en] We discuss cosmological solutions of Horava-Witten theory describing the strongly coupled heterotic string. At energies below the grand-unified scale, the effective theory is five, not four, dimensional, where the additional coordinate parametrizes an S¹/Z₂ orbifold. Furthermore, it admits no homogeneous solutions. Rather, the static vacuum state, appropriate for a reduction to four-dimensional N=1 supersymmetric models, is a BPS domain wall pair. Relevant cosmological solutions are those associated with this BPS state. In particular, such solutions must be inhomogeneous, depending on the orbifold coordinate as well as on time. We present two examples of this new type of cosmological solution, obtained by separation of variables rather than by exchange of the time and radius coordinates of a brane solution, as in previous work. The first example represents the analogue of a rolling radii solution with the radii specifying the geometry of the domain wall pair. This is generalized in the second example to include a nontrivial Ramond-Ramond scalar. copyright 1999 The American Physical Society

[en] Hierarchical quark masses and small mixing angles are shown to lead to a simple triangular form for U- and D-type quark mass matrices. In the basis where one of the matrices is diagonal, each matrix element of the other is, to a good approximation, the product of a quark mass and a CKM matrix element. The physical content of a general mass matrix can be easily deciphered in its triangular form. This parametrization could serve as a useful starting point for model building. Examples of mass textures are analyzed using this method. copyright 1999 The American Physical Society

[en] We analyze the signal at the Fermilab Tevatron for the doubly charged Higgs superfield of supersymmetric left-right models with gauge mediated supersymmetry breaking. Because of the presence of a new coupling, the lighter stau is usually less massive than the lightest neutralino and is frequently the next to lightest SUSY particle. The fermionic part of the doubly charged Higgs field decays dominantly into two τ leptons plus missing energy (gravitino). We find that the inclusive two τ jets (when they come from same sign τ jets) and three τ jets plus missing energy signatures could be observable at run II of the Tevatron. We also find that the distribution in angle between the two highest E_T τ jets when they come from same sign τ leptons can be used to distinguish this model from the others. copyright 1999 The American Physical Society

[en] We investigate a large class of supersymmetric SO(10) grand unified theories (GUT close-quote s) within the framework of gauge-mediated supersymmetry breaking. We start with the most general messenger sector and embed the standard model gauge group into either SU(2)_LxSU(2)_RxU(1)_B-L or SU(2)_LxU(1)_I3RxU(1)_B-L. We find that the conditions of the perturbativity of the gauge couplings and unification at the GUT scale severely restrict the messenger sector and lead to testable phenomenological predictions for the sparticle masses. One of the most notable features of the class of supersymmetric SO(10) grand unified theories introduced here is that among the many possible cases there are only a few consistent models, all of which share an essentially unique mass spectrum. copyright 1999 The American Physical Society

[en] In this Brief Report, a non-standard solution to the solar neutrino problem is reexamined. This solution assumes that neutrino flavors could have different couplings to gravity; hence, the equivalence principle is violated in this mechanism. The gravity induced mixing has the potential of accounting for the current solar neutrino data from several experiments even for massless neutrinos. We fit this solution to the total rate of neutrino events in the SuperKamiokande detector (first 504 days) together with the total rate from other detectors and also with the SuperKamiokande results for the recoil-electron spectrum. copyright 1999 The American Physical Society