نتایج جستجو برای: dynamic or decay
تعداد نتایج: 3897382 فیلتر نتایج به سال:
The Dubna-Mainz-Taipei dynamical model for pion electromagnetic production, which can describe well the existing data from threshold up to 1 GeV photon lab energy, is presented and used to analyze the recent precision data in the ∆ region. We find that, within our model, the bare ∆ is almost spherical while the physical ∆ is oblate. The deformation is almost saturated by the pion cloud effects....
We study the pion-nucleon P33 and P11 scattering, where the Delta and the Roper resonances are seen, respectively. We use the Lippmann-Schwinger equation extended to couple to a one-body state, and investigate nature of these resonances by taking and omitting a one-baryon state into account. We see validity and puzzle of the standard quark model interpretation, for the Delta and the Roper reson...
TheG-matrix equation is most straightforwardly formulated in the resonatinggroup method if the quark-exchange kernel is directly used as the driving term for the infinite sum of all the ladder diagrams. The inherent energydependence involved in the exchange term of the normalization kernel plays the essential role to define the off-shell T -matrix uniquely when the complete Pauli-forbidden stat...
We study the decays into six quarks of off-shell pairs of W± bosons produced in electronpositron annihilations, through the O(αs) order in the strong coupling constant. We give explicit helicity amplitude formulae. We present numerical results in the context of phenomenological analyses of relevance at LEP2 and future Linear Colliders: such as MW determinations, New Physics and Higgs searches. ...
Meson decay constants in the B system are used to translate measurements of BB̄ mixing to CKMmatrix elements. Currently, it is not possible to determine fB accurately from leptonic B decays, so theoretical calculations of fB are used. Since the B s meson does not have l ν decays, it will never be possible to determine fBs experimentally, thus theory must be relied on. If calculations disagree on...
ar X iv : h ep - p h / 06 01 18 1 v 1 21 J an 2 00 6 Progress in computing inclusive B decay spectra
We review the progress in the QCD calculation of inclusive decay spectra. It was recently shown that the inherent infrared finiteness of inclusive spectra extends beyond the level of logarithms. Dressed Gluon Exponentiation makes practical use of this property by computing the Sudakov exponent as a Borel sum. Based on renormalon analysis, infrared sensitivity in the exponent is reflected in pow...
Anti-de Sitter supergravity models are considered in three dimensions. Precise asymptotic conditions involving a chiral projection are given on the Rarita-Schwinger elds. Together with the known boundary conditions on the bosonic elds, these ensure that the asymptotic symmetry algebra is the superconformal algebra. The classical central charge is computed and found to be equal to the one of pur...
The DLS collaboration has recently completed a high statistics study of dilepton production at the Bevalac. In particular, we have measured dielectrons (e+e-) from p-p and p-d collisions to understand the basic dilepton production mechanisms in the energy range from 1.05 4.9 GeV. These data can be used to determine the basic processes which contribute to nucleon-nucleon dilepton production such...
General Relativity with nonvanishing torsion has been investigated in the first order formalism of Poincaré gauge field theory. In the presence of torsion, either side of the Einstein equation has the nonvanishing covariant divergence. This fact turned out to be self-consistent in the framework under consideration. By using Noether’s procedure with the definition of the Lie derivative where the...
The associated production of a W boson with a jet originating from either a light parton or heavy-flavor quark is studied in the forward region using proton-proton collisions. The analysis uses data corresponding to integrated luminosities of 1.0 and 2.0 fb−1 collected with the LHCb detector at center-of-mass energies of 7 and 8 TeV, respectively. The W bosons are reconstructed using the W → μν...
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