相关论文: Remarks on the Delta(+) mass

From the pion production rates n_{pi} / A_{part} and the pion charge ratios R_{pi} = n_{pi^-} / n_{pi^+} and S_{pi} = n_{pi^0} / (n_{pi^-} + n_{pi^+}), measured in p + A and A + A reactions, it is concluded that the mass of the Delta(1232)…

A fit to the existing pion electroproduction data is presented. This work builds upon our previous analyses of pion photoproduction and elastic pion-nucleon scattering over the Delta resonance region. We comment on the extraction of E_1+…

The elastic and radiative pion(+)-proton scattering are studied in the framework of an effective Lagrangian model for the Delta^{++} resonance and its interactions. The finite width effects of this spin-3/2 resonance are introduced in the…

We have studied the gamma d ---> Delta++ Delta- reaction which requires the collaboration of the two nucleons in deuteron. By means of a model previously developed for the gamma p ----> p pi+ pi- reaction, the two body exchange currents…

Extension of the separation geometry model of baryon structure from physics/0109024 and hep-ph/0201270 to the spin 2/3 Delta baryons. Theoretically derived masses in Mev; $\Delta^{++}=1240.0, \Delta^-=1243.4, \Delta^0=1233.9,…

Previous extrapolations of lattice QCD results for the nucleon mass to the physically relevant region of small quark masses, using chiral effective field theory, are extended and expanded in several directions. A detailed error analysis is…

A number of recent multipole analyses from Mainz, RPI, BNL and Virginia Tech (VPI) have focused on the first resonance region. One goal common to these studies was an improved set of Delta(1232) photo-decay amplitudes. There has been…

We evaluate the accuracy of traditional estimators often used to extract N to Delta quadrupole ratios from cross section angular distributions for pion electroproduction. We find that neither M1+ dominance nor sp truncation is sufficiently…

We present an overview of our efforts to analyze pion-nucleon elastic scattering data, along with data from related photo- and electroproduction reactions, in order to study the baryon spectrum. We then focus on the Delta(1232) resonance.…

Within the framework of the standard model we observe that there is a significant discrepancy between the most precise $Z$ boson decay asymmetry measurement and the limit from direct searches for Higgs boson production. Using methods…

The deuteron spectrum in n+p -> d+pi+pi at k_n = 1.88 GeV/c and theta_d = 0 deg is explained by considering a Delta-Delta excitation as the reaction mechanism for the 2pi production. We study the influence of intermediate Delta-Delta and…

We analyze the currently available observations of X-ray binaries in a consistent way, to re-determine the masses of the neutron stars in these systems. In particular, our attention is focussed on a realistic and consistent assessment of…

An updated and extended analysis of the quark mass dependence of the nucleon's axial vector coupling constant g_A is presented in comparison with state-of-the-art lattice QCD results. Special emphasis is placed on the role of the…

It is shown that a recent extraction of the total cross section for pp->K+ n Sigma+ from inclusive K+ production data is in conflict with experimental data on the exclusive pp->K+ p Lambda reaction. The result may be interpreted as an upper…

Theoretical predictions for the magnetic moments of the physical Delta baryons are extracted from lattice QCD calculations. We utilize finite-range regulated effective field theory that is constructed to have the correct Dirac moment mass…

We report the current status of Delta-md measurements at B-factories. The most recent world average is Delta-md = 0.502+-0.007 1/ps (1.4% accuracy). An estimate of the errors for 500 1/fb data is also given.

The K2K experiment has presented the first results on the observation of nu_mu. They show a depletion compared to the expectations and are consistent with neutrino oscillations with a mass-splitting in the range favoured by the…

Pion-nucleus elastic scattering at energies above the Delta(1232) resonance is studied using both pi+ and pi- beams on 12C, 40Ca, 90Zr, and 208Pb. The present data provide an opportunity to study the interaction of pions with nuclei at…

We consider variation of coupling strengths and mass ratios in and beyond the Standard Model, in the light of various mechanisms of mass generation. In four-dimensional unified models, variations in charged particle thresholds, light quark…

Within the multiple scattering formulation, the incoherent pion production in neutrino-deuteron reactions at energies near the $\Delta(1232)$ resonance is investigated. The calculations include an impulse term and one-loop contributions…