相关论文: Remarks on the Delta(+) mass
We make a study of the (pi^- p --> K^0 pi^0 Lambda), (pi^+ p --> K^+ pi^+ Lambda), (K^+\bar{K}^0 p), (K^+ pi^+ Sigma^0), (K^+ pi^0 Sigma^+), and (eta pi^+ p) reactions, in which the basic dynamics is given by the excitation of the…
If the "Higgs mass" is not the physical mass of a real particle but rather an effective ultraviolet cutoff then a process energy dependence of this cutoff must be admitted. Precision data from at least two energy scale experimental points…
Recent information on invariant mass distributions of the $\gamma p\to\pi^+\pi^0 n$ reaction, where previous theoretical models had shown deficiencies, have made more evident the need for new mechanisms, so far neglected or inaccurately…
The ratio Phi->K+K-/K0K0bar is discussed and its present experimental value is compared with theoretical expectations. A difference larger than two standard deviations is observed. We critically examine a number of mechanisms that could…
The latest $\pi N$ elastic scattering data are re-analysed to determine the coupling constant $g_c$ of the charged pion, using the dispersion relation for the invariant amplitude $B^{(+)}$. Depending on the choice of data-base, values…
Neutrino masses are yet unknown. We discuss the present state of effective electron anti-neutrino mass from $\beta$ decay experiments; effective Majorana neutrino mass from neutrinoless double-beta decay experiments; neutrino mass squared…
We examine the role of the Delta-Delta intermediate state in low energy NN scattering using effective field theory. Theories both with and without pions are discussed. They are regulated with dimensional regularization and MSbar…
The Baldin sum rule for the nucleon has been recalculated at the light of the most recent photoabsorption cross section measurements. The proton value (alpha + beta)_p =13.69 +/- 0.14 is smaller but consistent with the one usually quoted in…
A recent analysis of pion photo-production multipoles using p(g,pi0) data from Mainz is repeated, successively adding constraints from other observables and varying the number of fitted partial waves. The original analysis is shown to have…
We present calculations of the N N -> N Delta cross section in nuclear matter within the one-pion exchange model taking into account pion collectivity, vertex renormalization by the contact nuclear interactions and Dirac effective masses of…
We study the elastic and radiative pi+ p scattering within a full dynamical model which incorporates the finite width effects of the Delta++. The scattering amplitudes are invariant under contact transformations of the spin 3/2 field and…
Experimental data on the pion-nucleus total cross sections are analyzed in terms of the optimal resonances predictions (OR). The OR-predictions are found in a good agreement with the actual experimental data in the region corresponding to…
We have updated our multipole analyses to incorporate new data from the low-energy and delta resonance regions. We note a slight decrease in our estimate of the delta photo-decay amplitudes. This agrees with results found in Compton…
We investigate the model dependence and the importance of choice of database in extracting the {\it physical} nucleon-Delta(1232) electromagnetic transition amplitudes, of interest to QCD and baryon structure, from the pion photoproduction…
MiniBooNE [1] and MINERvA [2] charge current {\pi} + production data in the Delta region are discussed. It is argued that despite the differences in neutrino flux they measure the same dynamical mechanism of pion production and should be…
The ratio $\Delta m_K/m_K$ within the standard model with 3 generations is calculated as a function of the CP nonconserving phase $\delta_{13}$ and the quark masses $m_c,m_t$ assuming the current values of the Cabibbo-Kobayashi-Maskawa…
We review our evaluation of forward dispersion relations for direct fits to the different, and often conflicting, pion-pion scattering experimental analyses. We find that some of the most commonly used data sets do not satisfy these…
We study the Delta^{++} contributions to elastic and radiative \pi^+p scattering within an effective Lagrangian model which incorporates the Delta, N, rho and sigma meson degrees of freedom. This model provides a description of the Delta…
We measure the mass difference, $\Delta m_+$, between the $D^{*}(2010)^+$ and the $D^+$ using the decay chain $D^{*}(2010)^+\to D^+ \pi^0$ with $D^+\to K^-\pi^+\pi^+$. The data were recorded with the BABAR detector at center-of-mass…
A new partial wave analysis of pion photoproduction has been obtained in the framework of fixed-t dispersion relations valid form threshold up to 500 MeV. It is based on new Mainz data for \pi^{0} and \pi^{+} production off the proton and…