Search results for "SCALAR"
showing 10 items of 1002 documents
Case in favor of theN*(1700)(3/2−)
2013
Using an interaction extracted from the local hidden-gauge Lagrangians, which brings together vector and pseudoscalar mesons, and the coupled channels rho N (s wave), pi N (d wave), pi Delta (s wave), and pi Delta (d wave), we look in the region ofv root s = 1400-1850 MeV and find two resonances dynamically generated by the interaction of these channels, which are naturally associated to N*(1520)(3/2(-)) and N*(1700)(3/2(-)). N*(1700)(3/2(-)) appears neatly as a pole in the complex plane. The free parameters of the theory are chosen to fit the pi N (d-wave) data. Both the real and imaginary parts of the pi N amplitude vanish in our approach in the vicinity of this resonance, which is simila…
a 0 (980)− f 0 (980) mixing in χ c1 → π 0 f 0 (980)→ π 0 π + π − and χ c1 → π 0 a 0 (980)→ π 0 π 0 η
2017
Abstract We study the isospin breaking in the reactions χ c 1 → π 0 π + π − and χ c 1 → π 0 π 0 η and its relation to the a 0 ( 980 ) − f 0 ( 980 ) mixing, which was measured by the BESIII Collaboration. We show that the same theoretical model previously developed to study the χ c 1 → η π + π − reaction (also measured by BESIII), and further explored in the predictions to the η c → η π + π − , can be successfully employed in the present study. We assume that the χ c 1 behaves as an S U ( 3 ) singlet to find the weight in which trios of pseudoscalars are created, followed by the final state interaction of pairs of mesons to describe how the a 0 ( 980 ) and f 0 ( 980 ) are dynamically generat…
B¯0decay intoD0andf0(500),f0(980),a0(980),ρandB¯s0decay intoD0andκ(800),K*0
2015
We make predictions for ratios of branching fractions of ${\overline{B}}^{0}$ decays into ${D}^{0}$ and the scalar mesons ${f}_{0}(500)$, ${f}_{0}(980)$, ${a}_{0}(980)$, plus ${\overline{B}}_{s}^{0}$ decay into ${D}^{0}$ and $\ensuremath{\kappa}(800)$. We also compare the ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ production in the scalar channel with that observed in the $\ensuremath{\rho}$ channel and make predictions for the ${\overline{B}}_{s}^{0}$ decay into ${D}^{0}$ and ${K}^{*}(892)$, comparing the strength of this channel with that of $\ensuremath{\kappa}(800)$ production. The work is based on results of the chiral unitary approach where the scalar resonances are g…
The axial isoscalar neutral current from inelastic electron-nuclear scattering
1978
Abstract Parity violating effects due to neutral currents in isoscalar 0+→1+ nuclear transitions induced by electron scattering are enhanced owing to the small isoscalar magnetic dipole strength. A polarization asymmetry of the order 10−4 is expected at q ∼ 100 MeV for the 12C transition to the 1+(T = 0) state at 12.71 MeV. It would allow to single out the (electron vector current) × (hardonic axial isoscalar current) quantum numbers and couplings of the neutral current interaction.
Effective Boost and 'Point Form' Approach
2002
Triangle Feynman diagrams can be considered as describing form factors of states bound by a zero-range interaction. These form factors are calculated for scalar particles and compared to point-form and non-relativistic results. By examining the expressions of the complete calculation in different frames, we obtain an effective boost transformation which can be compared to the relativistic kinematical one underlying the present point-form calculations, as well as to the Galilean boost. The analytic expressions obtained in this simple model allow a qualitative check of certain results obtained in similar studies. In particular, a mismatch is pointed out between recent practical applications o…
RPA calculations with Gaussian expansion method
2009
The Gaussian expansion method (GEM) is extensively applied to the calculations in the random-phase approximation (RPA). We adopt the mass-independent basis-set that has been tested in the mean-field calculations. By comparing the RPA results with those obtained by several other available methods for Ca isotopes, using a density-dependent contact interaction and the Woods-Saxon single-particle states, we confirm that energies, transition strengths and widths of their distribution are described by the GEM bases to good precision, for the $1^-$, $2^+$ and $3^-$ collective states. The GEM is then applied to the self-consistent RPA calculations with the finite-range Gogny D1S interaction. The sp…
Linear response of light deformed nuclei investigated by self-consistent quasiparticle random-phase approximation
2010
We present a calculation of the properties of vibrational states in deformed, axially-symmetric even-even nuclei, within the framework of a fully self-consistent quasiparticle random phase approximation (QRPA). The same Skyrme energy density and density-dependent pairing functionals are used to calculate the mean field and the residual interaction in the particle-hole and particle-particle channels. We have tested our software in the case of spherical nuclei against fully self-consistent calculations published in the literature, finding excellent agreement. We investigate the consequences of neglecting the spin-orbit and Coulomb residual interactions in QRPA. Furthermore we discuss the impr…
Study of a possible S=+1 dynamically generated baryonic resonance
2005
Starting from the lowest order chiral Lagrangian for the interaction of the baryon decuplet with the octet of pseudoscalar mesons we find an attractive interaction in the $\Delta K$ channel with L=0 and I=1, while the interaction is repulsive for I=2. The attractive interaction leads to a pole in the second Riemann sheet of the complex plane and manifests itself in a large strength of the $\Delta K$ scattering amplitude close to the $\Delta K$ threshold, which is not the case for I=2. However, we also make a study of uncertainties in the model and conclude that the existence of this pole depends sensitively upon the input used and can disappear within reasonable variations of the input para…
Dispersive representation of the scalar and vector Kπ form factors for and decays
2011
Recently, the τ → K π ν τ decay spectrum has been measured by the Belle and BaBar collaborations. In this work, we present an analysis of such decays introducing a dispersive parametrization for the vector and scalar Kπ form factors. This allows for precise tests of the Standard Model. For instance, the determination of f + ( 0 ) | V u s | from these decays is discussed. A comparison and a combination of these results with the analyses of the K l 3 decays is also considered.
Search for pair production of first-generation leptoquarks in pp¯ collisions at s=1.96 TeV
2009
A search for pair production of first-generation leptoquarks LQ is performed with data collected by the D0 experiment in p pbar collisions at sqrt(s)=1.96 TeV at the Fermilab Tevatron Collider. In a sample of data corresponding to ~1 fb-1, the search has been performed on the final states with two electrons and two jets or one electron, two jets and missing transverse energy. We find our data consistent with standard model expectations. The results are combined with those found in a previous analysis of events with two jets and missing transverse energy to obtain scalar LQ mass limits. We set 95% C.L. lower limits on a scalar LQ mass of 299 GeV, 284 GeV and 216 GeV for beta=1, beta=0.5 and …