Search results for "Pseudoscalar meson"
showing 10 items of 40 documents
The role of resonances in chiral perturbation theory
1989
32 páginas, 2 figuras, 5 tablas.-- BUTP-88-18 ; CERN-TH-5185-88 ; CPT-2158 ; UWTHPH-1988-29.
Three pseudoscalar meson production ine+e−annihilation
2013
Conversations with German Rodrigo on the topic of this paper are warmly acknowledged. We would like to thank Henryk Czyz for fruitful discussions on context of MC PHOKHARA 7.0. We also wish to thank Michael R. Pennington for a careful reading of our manuscript and for his suggestions. Lingyun Dai thanks the China Scholarship Council for their support. This research has been supported in part by the funds of the Polish National Science Centre under decisions DEC-2012/04/M/ST2/00240 and DEC-2011/03/B/ST2/00107 (O. S.) and by the Spanish Government and ERDF funds from the EU Commission [Grants No. FPA2007-60323, No. FPA2011-23778, No. CSD2007-00042 (Consolider Project CPAN)]. This paper has be…
Searches for B0 decays to combinations of charmless isoscalar mesons
2004
We search for B meson decays into two-body combinations of eta, eta', omega, and phi mesons from 89 million B B-bar pairs collected with the BaBar detector at the PEP-II asymmetric-energy e+e- collider at SLAC. We find the branching fraction BF(B0 -> eta omega) = (4.0^{+1.3}_{-1.2} +- 0.4) x 10^-6 with a significance of 4.3 sigma. For all the other decay modes we set the following 90% confidence level upper limits on the branching fractions, in units of 10^-6 : BF(B0 -> eta eta)<2.8, BF(B0 -> eta eta')<4.6, BF(B0 -> eta' eta')<10, BF(B0 -> eta'omega)<2.8, BF(B0 -> eta phi)<1.0, BF(B0 -> eta' phi)<4.5, BF(B0 -> phi phi)<1.5.
Measurement of branching fractions for D meson decaying into $ϕ$ meson and a pseudoscalar meson
2019
The four decay modes D0→ϕπ0, D0→ϕη, D+→ϕπ+, and D+→ϕK+ are studied by using a data sample taken at the centre-of-mass energy s=3.773 GeV with the BESIII detector, corresponding to an integrated luminosity of 2.93 fb$^{−1}$. The branching fractions of the first three decay modes are measured to be B(D0→ϕπ0)=(1.168±0.028±0.028)×10−3, B(D0→ϕη)=(1.81±0.46±0.06)×10−4, and B(D+→ϕπ+)=(5.70±0.05±0.13)×10−3, respectively, where the first uncertainties are statistical and the second are systematic. In addition, the upper limit of the branching fraction for D+→ϕK+ is given to be 2.1×10−5 at the 90% confidence level. The ratio of B(D0→ϕπ0) to B(D+→ϕπ+) is calculated to be (20.49±0.50±0.45)%, which is c…
Effective Majorana mass matrix from tau and pseudoscalar meson lepton number violating decays
2018
An observation of any lepton number violating process will undoubtedly point towards the existence of new physics and indirectly to the clear Majorana nature of the exchanged fermion. In this work, we explore the potential of a minimal extension of the Standard Model via heavy sterile fermions with masses in the $[ 0.1 - 10]$ GeV range concerning an extensive array of "neutrinoless" meson and tau decay processes. We assume that the Majorana neutrinos are produced on-shell, and focus on three-body decays. We conduct an update on the bounds on the active-sterile mixing elements, $|U_{\ell_\alpha 4} U_{\ell_\beta 4}|$, taking into account the most recent experimental bounds (and constraints) a…
Masses and decay constants of D(s)* and B(s)* mesons with Nf=2+1+1 twisted mass fermions
2017
We present a lattice calculation of the masses and decay constants of ${D}_{(s)}^{*}$ and ${B}_{(s)}^{*}$ mesons using the gauge configurations produced by the European Twisted Mass Collaboration (ETMC) with ${N}_{f}=2+1+1$ dynamical quarks at three values of the lattice spacing $a\ensuremath{\sim}(0.06\ensuremath{-}0.09)\text{ }\text{ }\mathrm{fm}$. Pion masses are simulated in the range ${M}_{\ensuremath{\pi}}\ensuremath{\simeq}(210--450)\text{ }\text{ }\mathrm{MeV}$, while the strange and charm sea-quark masses are close to their physical values. We compute the ratios of vector to pseudoscalar masses and decay constants for various values of the heavy-quark mass ${m}_{h}$ in the range $0…
Phenomenological applications of rational approximants
2016
We illustrate the powerfulness of Padé approximants (PAs) as a summation method and explore one of their extensions, the so-called quadratic approximant (QAs), to access both space- and (low-energy) time-like (TL) regions. As an introductory and pedagogical exercise, the function [Formula: see text] is approximated by both kind of approximants. Then, PAs are applied to predict pseudoscalar meson Dalitz decays and to extract [Formula: see text] from the semileptonic [Formula: see text] decays. Finally, the [Formula: see text] vector form factor in the TL region is explored using QAs.
X(2175)as a resonant state of theϕKK¯system
2008
We perform a Faddeev calculation for the three-meson system $\ensuremath{\phi}K\overline{K}$, taking the interaction between two pseudoscalar mesons and between a vector and a pseudoscalar meson from the chiral unitary approach. We obtain a neat resonance peak around a total mass of 2150 MeV and an invariant mass for the $K\overline{K}$ system around 970 MeV, very close to the ${f}_{0}(980)$ mass. The state appears in $I=0$ and qualifies as a $\ensuremath{\phi}{f}_{0}(980)$ resonance. We enlarge the space of states including $\ensuremath{\phi}\ensuremath{\pi}\ensuremath{\pi}$, since $\ensuremath{\pi}\ensuremath{\pi}$ and $K\overline{K}$ build up the ${f}_{0}(980)$, and find moderate changes…
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…
Search for newπ0-like particles produced in association with aτ-lepton pair
2014
We report on a search in e^+e^− annihilations for new π^0-like particles produced in association with a τ-lepton pair. These objects, with a similar mass and similar decay modes to π^0 mesons, could provide an explanation for the non-asymptotic behavior of the pion-photon transition form factor observed by the BABAR Collaboration. No significant signal is observed, and limits on the production cross section at the level of 73 fb or 370 fb, depending on the model parameters, are determined at 90% confidence level. These upper limits lie below the cross section values needed to explain the BABAR form factor data.