The cross sections of the \(e^{+}e^{-}\to\phi\eta'\) process at center-of-mass energies from 3.508 to 4.951 GeV are measured with high precision using 26.1 fb\(^{-1}\) data collected with the BESIII ...detector operating at the BEPCII storage ring. The cross sections are of the order of a few picobarn, and decrease as the center-of-mass energy increases as \(s^{-n/2}\) with \(n=4.35\pm 0.14\). This result is in agreement with the Nambu-Jona-Lasinio model prediction of \(n=3.5\pm 0.9\). In addition, the charmless decay \(\psi(3770)\to\phi\eta'\) is searched for by fitting the measured cross sections, yet no significant signal is observed. The upper limit of \({\cal B}(\psi(3770)\to\phi\eta')\) at the 90\% confidence level is determined to be \(2.3\times 10^{-5}\).
Phys. Rev. Lett. 122, 102002 (2019) The cross section of the process $e^+e^-\to \pi^+D^0D^{*-}$ for
center-of-mass energies from 4.05 to 4.60~GeV is measured precisely using data
samples collected ...with the BESIII detector operating at the BEPCII storage
ring.
Two enhancements are clearly visible in the cross section around 4.23 and
4.40~GeV.
Using several models to describe the dressed cross section yields stable
parameters for the first enhancement, which has a mass of $4228.6 \pm 4.1 \pm
6.3 \un{MeV}/c^2$ and a width of $77.0 \pm 6.8 \pm 6.3 \un{MeV}$, where the
first uncertainties are statistical and the second ones are systematic.
Our resonant mass is consistent with previous observations of the $Y(4220)$
state and the theoretical prediction of a $D\bar{D}_1(2420)$ molecule.
This result is the first observation of $Y(4220)$ associated with an
open-charm final state.
Fits with three resonance functions with additional $Y(4260)$, $Y(4320)$,
$Y(4360)$, $\psi(4415)$, or a new resonance, do not show significant
contributions from either of these resonances. The second enhancement is not
from a single known resonance. It could contain contributions from $\psi(4415)$
and other resonances, and a detailed amplitude analysis is required to better
understand this enhancement.
Using 16 energy points of $e^{+}e^{-}$ annihilation data collected in the
vicinity of the $J/\psi$ resonance with the BESIII detector and with a total
integrated luminosity of around 100 pb$^{-1}$, ...we study the relative phase
between the strong and electromagnetic amplitudes of $J/\psi$ decays. The
relative phase between $J\psi$ electromagnetic decay and the continuum process
($e^{+}e^{-}$ annihilation without the $J/\psi$ resonance) is confirmed to be
zero by studying the cross section lineshape of $\mu^{+}\mu^{-}$ production.
The relative phase between $J/\psi$ strong and electromagnetic decays is then
measured to be $(84.9\pm3.6)^\circ$ or $(-84.7\pm3.1)^\circ$ for the
$2(\pi^{+}\pi^{-})\pi^{0}$ final state by investigating the interference
pattern between the $J/\psi$ decay and the continuum process. This is the first
measurement of the relative phase between $J/\psi$ strong and electromagnetic
decays into a multihadron final state using the lineshape of the production
cross section. We also study the production lineshape of the multihadron final
state $\eta\pi^{+}\pi^{-}$ with $\eta\to\pi^{+}\pi^{-}\pi^{0}$, which provides
additional information about the phase between the $J/\psi$ electromagnetic
decay amplitude and the continuum process. Additionally, the branching fraction
of $J/\psi\to 2(\pi^{+}\pi^{-})\pi^{0}$ is measured to be $(4.73\pm0.44)\%$ or
$(4.85\pm0.45)\%$, and the branching fraction of $J/\psi\to\eta\pi^{+}\pi^{-}$
is measured to be $(3.78\pm0.68)\times10^{-4}$. Both of them are consistent
with the world average values. The quoted uncertainties include both
statistical and systematic uncertainties, which are mainly caused by the low
statistics.
Electron-ion recombination of Be-like 40Ar14+ has been measured by employing the electron-ion merged-beams method at the cooler storage ring CSRm. The measured absolute recombination rate ...coefficients for collision energies from 0 to 60 eV are presented, covering all dielectronic recombination (DR) resonances associated with 2s2 → 2s2p core transitions. In addition, strong trielectronic recombination (TR) resonances associated with 2s2 → 2p2 core transitions were observed. Both DR and TR processes lead to series of peaks in the measured recombination spectrum, which have been identified by the Rydberg formula. Theoretical calculations of recombination rate coefficients were performed using the state-of-the-art multi-configuration Breit-Pauli atomic structure code AUTOSTRUCTURE to compare with the experimental results. The plasma rate coefficients for DR+TR of Ar14+ were deduced from the measured electron-ion recombination rate coefficients in the temperature range from 103 to 107 K, and compared with calculated data from the literature. The experimentally derived plasma rate coefficients are 60% larger and 30% lower than the previously recommended atomic data for the temperature ranges of photoionized plasmas and collisionally ionized plasmas, respectively. However, good agreement was found between experimental results and the calculations by Gu and Colgan et al. The plasma rate coefficients deduced from experiment and calculated by the current AUTOSTRUCTURE code show agreement that is better than 30% from 104 to 107 K. The present results constitute a set of benchmark data for use in astrophysical modeling.
Using \(e^+e^-\) collision data with an integrated luminosity of \(7.33~\mathrm{fb}^{-1}\) collected at center-of-mass energies between 4.128 and 4.226 GeV with the BESIII detector operating at the ...BEPCII collider, the branching fraction of the leptonic decay \(D_s^+\to\mu^+\nu_\mu\) is measured to be \((0.5294\pm0.0108_{\rm stat}\pm0.0085_{\rm syst})\)\%. Based on this, the product of the \(D_s^+\) decay constant \(f_{D_s^+}\) and the magnitude of the \(c\to s\) quark mixing matrix element \(|V_{cs}|\) is determined to be \(f_{D_s^+}|V_{cs}|=241.8\pm2.5_{\rm stat}\pm2.2_{\rm syst}~\mathrm{MeV}\). Using the value of \(|V_{cs}|\) given by the global standard model fit, \(f_{D_s^+}\) is found to be \(248.4\pm2.5_{\rm stat}\pm2.2_{\rm syst}\)\,MeV. Alternatively, using the value of \(f_{D_s^+}\) from a recent lattice quantum chromodynamics calculation, \(|V_{cs}|\) is determined to be \(0.968\pm0.010_{\rm stat}\pm0.009_{\rm syst}\).
Phys. Lett. B 783 (2018) 452-458 Using a data sample of $448.1 \times 10^6$ $\psi(3686)$ events collected with
the BESIII detector at the BEPCII collider, we report the first observation of
the ...electromagnetic Dalitz decay $\psi(3686) \to \eta' e^+ e^-$, with
significances of 7.0$\sigma$ and 6.3$\sigma$ when reconstructing the $\eta'$
meson via its decay modes $\eta'\to\gamma \pi^+ \pi^-$ and
$\eta'\to\pi^+\pi^-\eta$ ($\eta \to \gamma\gamma$), respectively. The weighted
average branching fraction is determined to be $\mathcal{B}(\psi(3686) \to
\eta' e^+ e^-)= (1.90 \pm 0.25 \pm 0.11) \times 10^{-6}$, where the first
uncertainty is statistical and the second systematic.
The \(D^+_s\to K^+K^-\mu^+\nu_\mu\) decay is studied based on 7.33 fb\(^{-1}\) of \(e^+e^-\) collision data collected with the BESIII detector at center-of-mass energies in the range from 4.128 to ...4.226 GeV. The absolute branching fraction is measured as \({\mathcal B}(D^+_s\to \phi \mu^+\nu_\mu) = (2.25\pm 0.09 \pm 0.07) \times10^{-2}\), the most precise measurement to date. Combining with the world average of \({\mathcal B}(D^+_s\to \phi e^+\nu_e)\), the ratio of the branching fractions obtained is\(\frac{{\mathcal B}(D^+_s\to \phi \mu^+\nu_\mu)}{{\mathcal B}(D^+_s\to \phi e^+\nu_e)} = 0.94\pm0.08\), in agreement with lepton universality. By performing a partial wave analysis, the hadronic form factor ratios at \(q^{2}=0\) are extracted, finding \(r_{V}=\frac{V(0)}{A_{1}(0)}=1.58\pm0.17\pm0.02\) and \(r_{2}=\frac{A_{2}(0)}{A_{1}(0)}=0.71\pm0.14\pm0.02\), where the first uncertainties are statistical and the second are systematic. No significant \(S\)-wave contribution from \(f_0(980)\to K^+K^-\) is found. The upper limit \(\mathcal{B}(D_s^+\to f_0(980)\mu^{+}{\nu}_{\mu}) \cdot{\mathcal B}(f_0(980)\to K^+K^-) < 5.45 \times 10^{-4}\) is set at 90\% confidence level.
The preservation effect of a new platelet solution--acidified glucose nutrient solution (AGN)--was tested by adding AGN to pooled platelet rich plasma (PRP) prior to preparation of platelet ...concentrates (PC). Each PRP unit was prepared from a unit of whole blood and four PRP of the same blood group were pooled in 400 ml volume PVC bags. Equal aliquots of each pooled PRP were made prior to preparation of PC. AGN was added to one aliquot and nothing was added to the control aliquot. Equal volume and concentration PC were then prepared and the PC were further aliquoted for storage at 22 degrees C. After five days, the parameters of platelet count, pH, aggregability and hypotonic shock response (HSR) for PC preserved in AGN plasma were better than those of the controls preserved in normal ACD plasma. The aggregability and HSR of AGN platelet concentrates recovered to baseline after two h of incubation with fresh plasma. The results of electron microscopy show that platelets preserved in AGN have less changes in morphology. The results of our work suggest that the preservation effect of AGN on PC is similar to the effect of using second generation containers or preparation of platelets from thrombocytapheresis.
Using a sample of \((10087\pm44)\times10^{6}\) \(J/\psi\) events collected with the BESIII detector at the BEPCII collider, a partial wave analysis on the decay \(\gamma\gamma\phi\) is performed to ...investigate the intermediate resonances in \(J/\psi\rightarrow\gamma X, X\rightarrow\gamma\phi\). The resonances \(f_{1}(1285)\), \(\eta(1405)\), \(f_{1}(1420)\), \(f_{1}(1510)\), \(f_{2}(1525)\), \(X(1835)\), \(f_{2}(1950)\), \(f_{2}(2010)\), \(f_{0}(2200)\) and \(\eta_{c}\) are observed with statistical significance greater than 5\(\sigma\). The product branching fractions \(\mathcal{B}(J/\psi\rightarrow\gamma X, X\rightarrow \gamma \phi)\) are reported. The resonance parameters of \(\eta(1405)\) and \(X(1835)\) are also measured.
Using \(e^+e^-\) collision datasets corresponding to total integrated luminosity of 21.7 fb\(^{-1}\) collected with the BESIII detector at the BEPCII collider at center-of-mass energies ranging from ...4.009 GeV to 4.951 GeV, the energy-dependent cross sections of \(e^+e^-\to pK^-\bar{\Lambda}+c.c.\) are measured for the first time. By fitting these energy-dependent cross sections, we search for the excited \(\psi\) states \(\psi(4160)\) and \(\psi(4415)\), and the vector charmonium-like states \(\psi(4230)\), \(\psi(4360)\), and \(\psi(4660)\). No evidence for these is observed and the upper limits on the branching fractions of these states decaying into \(pK^-\bar \Lambda+c.c.\) are set at the 90\% confidence level.
PDF
