Using data samples collected with the BESIII detector at the BEPCII collider
at center-of-mass energies ranging from 3.80 to 4.95 GeV, corresponding to an
integrated luminosity of 20 fb$^{-1}$, a ...measurement of Born cross sections for
the $e^+e^-\to D^{0}\bar{D}^{0}$ and $D^{+}D^{-}$ processes is presented with
unprecedented precision. By performing a simultaneous fit to the dressed cross
sections for both processes, one possible new structure around 3.9 GeV/$c^2$ is
observed for the first time, in addition to seven known resonances
$\psi(3770)$, $\psi(4040)$, $\psi(4160)$, $Y(4230)$, $Y(4360)$, $\psi(4415)$,
and $Y(4660)$. These results offer crucial experimental insights into the
nature of hadron production in the open charm region.
We present measurements of the Born cross sections for the processes
$e^+e^-\rightarrow\omega\chi_{c1}$ and $\omega\chi_{c2}$ at center-of-mass
energies $\sqrt{s}$ from 4.308 to 4.951 GeV. The ...measurements are performed
with data samples corresponding to an integrated luminosity of 11.0
$\rm{fb}^{-1}$ collected with the BESIII detector operating at the BEPCII
storage ring. Assuming the $e^+e^-\rightarrow\omega\chi_{c2}$ signals come from
a single resonance, the mass and width are determined to be
$M=(4413.6\pm9.0\pm0.8)$ MeV/$c^2$ and $\Gamma=(110.5\pm15.0\pm2.9)$ MeV,
respectively, which is consistent with the parameters of the well-established
resonance $\psi(4415)$. In addition, we also use one single resonance to
describe the $e^+e^-\rightarrow\omega\chi_{c1}$ lineshape, and determine the
mass and width to be $M=(4544.2\pm18.7\pm1.7)$ MeV/$c^2$ and
$\Gamma=(116.1\pm33.5\pm1.7)$ MeV, respectively. The structure of this
lineshape, observed for the first time, requires further understanding.
We report the measurement of the cross sections for $e^+e^-\rightarrow {\rm
hadrons}$ at center-of-mass (c.m.) energies from 3.645 to 3.871 GeV. We observe
a new resonance $\mathcal R(3810)$ in the ...cross sections for the first time,
and observe the $\mathcal R(3760)$ resonance with high significance in the
cross sections. The $\mathcal R(3810)$ has a mass of $(3804.5 \pm 0.9 \pm 0.9)$
~MeV/$c^2$, a total width of $(5.4 \pm 3.5 \pm 3.2)$~MeV, and an electronic
partial width of $(19.4 \pm 7.4 \pm 12.1)$~eV. Its significance is $7.7\sigma$.
The $\mathcal R(3810)$ could be interpreted as a hadro-charmonium resonance
predicted by Quantum Chromodynamics (QCD). In addition, we measure the mass
$(3751.9\pm 3.8\pm 2.8)$ ~MeV/$c^2$, the total width $(32.8 \pm 5.8 \pm
8.7)$~MeV, and the electronic partial width $(184\pm 75\pm 86)$~eV with
improved precision for the $\mathcal R(3760)$. Furthermore, for the $\mathcal
R(3780)$ we measure the mass $(3778.7\pm 0.5\pm 0.3)$ ~MeV/$c^2$ and total
width $(20.3 \pm 0.8 \pm 1.7)$~MeV with improved precision, and the electronic
partial width $(265\pm 69\pm 83)$~eV. The $\mathcal R(3780)$ can be interpreted
as the $1^3D_1$ state of charmonium. Its mass and total width differ
significantly from the corresponding fitted values given by the Particle Data
Group in 2022 by 7.1 and 3.2 times the uncertainties for $\psi(3770)$,
respectively. $\psi(3770)$ has been interpreted as the $1^3D_1$ state for 45
years.
A search has been performed for the semileptonic decays $D^{0}\to K_{S}^{0}
K^{-} e^{+}\nu_{e}$, $D^{+}\to K_{S}^{0} K_{S}^{0} e^{+}\nu_{e}$ and $D^{+}\to
K^{+}K^{-} e^{+}\nu_{e}$, using ...$7.9~\mathrm{fb}^{-1}$ of $e^+e^-$ annihilation
data collected at the center-of-mass energy $\sqrt{s}=3.773$ GeV by the BESIII
detector operating at the BEPCII collider. No significant signals are observed,
and upper limits are set at the 90\% confidence level of $2.13\times10^{-5}$,
$1.54\times10^{-5}$ and $2.10\times10^{-5}$ for the branching fractions of
$D^{0}\to K_{S}^{0} K^{-} e^{+}\nu_{e}$, $D^{+}\to K_{S}^{0} K_{S}^{0}
e^{+}\nu_{e}$ and $D^{+}\to K^{+}K^{-} e^{+}\nu_{e}$, respectively.
The first observation of the decays $J\!/\!\psi \rightarrow \bar{p}
\Sigma^{+} K_{S}^{0}$ and $J\!/\!\psi \rightarrow p \bar{\Sigma}^{-} K_{S}^{0}$
is reported using $(10087\pm44)\times10^{6}$ ...$J\!/\!\psi$ events recorded by
the BESIII detector at the BEPCII storage ring. The branching fractions of each
channel are determined to be $\mathcal{B}(J\!/\!\psi \rightarrow \bar{p}
\Sigma^{+} K_{S}^{0})=(1.361 \pm 0.006 \pm 0.025) \times 10^{-4}$ and
$\mathcal{B}(J\!/\!\psi \rightarrow p \bar{\Sigma}^{-} K_{S}^{0})=(1.352 \pm
0.006 \pm 0.025) \times 10^{-4}$. The combined result is
$\mathcal{B}(J\!/\!\psi \rightarrow \bar{p} \Sigma^{+} K_{S}^{0} +c.c.)=(2.725
\pm 0.009 \pm 0.050) \times 10^{-4}$, where the first uncertainty is
statistical and the second systematic. The results presented are in good
agreement with the branching fractions of the isospin partner decay $J\!/\!\psi
\rightarrow p K^- \bar\Sigma^0 + c.c.$.
The Beijing Spectrometer (BESIII) collaboration uses \(e^+e^-\) collisions in the tau-charm energy region to study a broad spectrum of topics. These include studies of light mesons and light baryons, ...studies of charmonium, including exotic mesons and baryons containing charmonium, studies of charmed mesons and baryons, studies of QCD and tau physics, as well as searches for new physics. The following is a Snowmass white paper that outlines the BESIII accomplishments and potential in each of these areas.
Phys. Rev. D 108, 092011 (2023) Based on $(27.08\pm 0.14)\times10^{8}$ $\psi(3686)$ events collected with the
BESIII detector operating at the BEPCII collider, the
...$\psi(3686)\to\Sigma^{+}\bar{\Sigma}^{-}\omega$ and
$\Sigma^{+}\bar{\Sigma}^{-}\phi$ decays are observed for the first time with
statistical significances of 13.8$\sigma$ and 7.6$\sigma$, respectively. The
corresponding branching fractions are measured to be
$\mathcal{B}(\psi(3686)\to\Sigma^{+}\bar{\Sigma}^{-}\omega)=(1.90 \pm 0.18 \pm
0.21) \times 10^{-5}$ and
$\mathcal{B}(\psi(3686)\to\Sigma^{+}\bar{\Sigma}^{-}\phi)=(2.96 \pm 0.54 \pm
0.41) \times 10^{-6}$, where the first uncertainties are statistical and the
second systematic.
Using a sample of about 10 billion $J/\psi$ events with the BESIII detector,
we search for the weak decays of $J/\psi \to \bar{D}^0\pi^0 + c.c.$, $J/\psi
\to \bar{D}^0\eta + c.c.$, $J/\psi \to ...\bar{D}^0\rho^0 + c.c.$, $J/\psi \to
D^-\pi^+ + c.c.$, and $J/\psi \to D^-\rho^+ + c.c.$. Since no significant
signal is observed, we set the upper limits of the branching fractions of these
decays to be $\mathcal{B}(J/\psi \to \bar{D}^0\pi^0 + c.c.) < 4.7 \times
10^{-7}$, $\mathcal{B}(J/\psi \to \bar{D}^0\eta + c.c.) < 6.8 \times 10^{-7}$,
$\mathcal{B}(J/\psi \to \bar{D}^0\rho^0 + c.c.) < 5.2 \times 10^{-7}$,
$\mathcal{B}(J/\psi \to D^-\pi^+ + c.c.) < 7.0 \times 10^{-8}$, and
$\mathcal{B}(J/\psi \to D^-\rho^+ + c.c.) < 6.0 \times 10^{-7}$ at the 90\%
confidence level.
Using $(10087\pm44)\times 10^{6}$ $J/\psi$ events collected with the BESIII
detector, numerous $\Xi^-$ and $\Lambda$ decay asymmetry parameters are
simultaneously determined from the process $J/\psi ...\to \Xi^- \bar{\Xi}^+ \to
\Lambda(p\pi^-) \pi^- \bar{\Lambda}(\bar{n} \pi^0) \pi^+$ and its
charge-conjugate channel. The precisions of $\alpha_0$ for $\Lambda \to n\pi^0$
and $\bar{\alpha}_0$ for $\bar{\Lambda} \to \bar{n}\pi^0$ compared to world
averages are improved by factors of 4 and 1.7, respectively. The ratio of decay
asymmetry parameters of $\Lambda \to n\pi^0$ to that of $\Lambda \to p\pi^-$,
$\langle \alpha_0 \rangle/ \langle \alpha_{\Lambda -} \rangle $, is determined
to be $ 0.873 \pm 0.012^{+0.011}_{-0.010}$, where the first and the second
uncertainties are statistical and systematic, respectively. The ratio is
smaller than unity more than $5\sigma$, which signifies the existence of the
$\Delta I = 3/2$ transition in $\Lambda$ for the first time. Beside, we test
for CP violation in $\Xi^- \to \Lambda \pi^-$ and in $\Lambda \to n \pi^{0}$
with the best precision to date.
JHEP01(2024)180 Based on $e^{+}e^{-}$ collision data collected at center-of-mass energies
from 2.000 to 3.080 GeV by the BESIII detector at the BEPCII collider, a
partial wave analysis is performed ...for the process $e^{+}e^{-}\to K_{S}^{0}
K_{L}^{0} \pi^{0}$. The results allow the Born cross sections of the process
$e^{+}e^{-}\to K_{S}^{0} K_{L}^{0} \pi^{0}$, as well as its subprocesses
$e^{+}e^{-}\to K^{*}(892)^{0}\bar{K}^{0}$ and $K^{*}_{2}(1430)^{0}\bar{K}^{0}$
to be measured. The Born cross sections for $e^{+}e^{-}\to
K_{S}^{0}K_{L}^{0}\pi^{0}$ are consistent with previous measurements by BaBar,
but with substantially improved precision. The Born cross section lineshape of
the process $e^{+}e^{-}\to K^{*}(892)^{0}\bar{K}^{0}$ is consistent with a
vector meson state around 2.2 GeV with a significance of 3.2$\sigma$. A
Breit-Wigner fit determines its mass as
$M_Y=(2164.7\pm9.1\pm3.1)~{\rm{MeV}}/c^{2}$ and its width as
$\Gamma_{Y}=(32.4\pm21.0\pm1.8)~\rm{MeV}$.