The Born cross sections of the processes $e^+e^–$ → $ωπ^0$ and $e^+e^–$ → $ωη$ are measured at center-of-mass energies between 3.773 and 4.701 GeV using a total integrated luminosity of 22.7 fb–1 ...collected with the BESIII detector operating at the BEPCII collider. A simple $s^{-n}$ dependence for the continuum process can describe the measured Born cross sections. No significant contributions from the ψ(4160), Y(4230), Y(4360), ψ(4415), Y(4660) resonances are found, which indicates relative small branching fractions for these resonances into the $ωπ^0$ and $ωη$ final states.
A bstract The $$ {D}_s^{+}\to {K}^{+}{K}^{-}{\mu}^{+}{\nu}_{\mu } $$ D s + → K + K − μ + ν μ 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 $$ \mathcal{B}\left({D}_s^{+}\to \phi {\mu}^{+}{\nu}_{\mu}\right)=\left(2.25\pm 0.09\pm 0.07\right)\times {10}^{-2} $$ B D s + → ϕ μ + ν μ = 2.25 ± 0.09 ± 0.07 × 10 − 2 , the most precise measurement to date. Combining with the world average of $$ \mathcal{B}\left({D}_s^{+}\to \phi {e}^{+}{\nu}_e\right) $$ B D s + → ϕ e + ν e , the ratio of the branching fractions obtained is $$ \frac{\mathcal{B}\left({D}_s^{+}\to \phi {\mu}^{+}{\nu}_{\mu}\right)}{\mathcal{B}\left({D}_s^{+}\to \phi {e}^{+}{\nu}_e\right)}=0.94\pm 0.08 $$ B D s + → ϕ μ + ν μ B D s + → ϕ e + ν e = 0.94 ± 0.08 , in agreement with lepton universality. By performing a partial wave analysis, the hadronic form factor ratios at q 2 = 0 are extracted, finding $$ {r}_V=\frac{V(0)}{A_1(0)}=1.58\pm 0.17\pm 0.02 $$ r V = V 0 A 1 0 = 1.58 ± 0.17 ± 0.02 and $$ {r}_2=\frac{A_2(0)}{A_1(0)}=0.71\pm 0.14\pm 0.02 $$ r 2 = A 2 0 A 1 0 = 0.71 ± 0.14 ± 0.02 , where the first uncertainties are statistical and the second are systematic. No significant S -wave contribution from f 0 (980) → K + K − is found. The upper limit $$ \mathcal{B}\left({D}_s^{+}\to {f}_0(980){\mu}^{+}{\nu}_{\mu}\right)\cdot \mathcal{B}\left({f}_0(980)\to {K}^{+}{K}^{-}\right)<5.45\times {10}^{-4} $$ B D s + → f 0 980 μ + ν μ ⋅ B f 0 980 → K + K − < 5.45 × 10 − 4 is set at 90% credibility level.
A
bstract
Using a total of 5
.
25 fb
−
1
of
e
+
e
−
collision data with center-of-mass energies from 4.236 to 4.600 GeV, we report the first observation of the process
e
+
e
−
→ ηψ
(2
S
) with a ...statistical significance of 4.9 standard deviations. The data sets were collected by the BESIII detector operating at the BEPCII storage ring. We measure the yield of events integrated over center-of-mass energies and also present the energy dependence of the measured cross section.
A
bstract
Using data samples with an integrated luminosity of 19 fb
−
1
at twenty-eight center-of-mass energies from 3.872 GeV to 4.700 GeV collected with the BESIII detector at the BEPCII ...electron-positron collider, the process
e
+
e
−
→
ηπ
+
π
−
and the intermediate process
e
+
e
−
→
ηρ
0
are studied for the first time. The Born cross sections are measured. No significant resonance structure is observed in the cross section lineshape.
A
bstract
Based on 4.5 fb
−
1
data taken at seven center-of-mass energies ranging from 4.600 to 4.699 GeV with the BESIII detector at the BEPCII collider, we measure the branching fractions of
$$ ...{\Lambda}_c^{+} $$
Λ
c
+
→
Σ
+
+
hadrons
relative to
$$ {\Lambda}_c^{+} $$
Λ
c
+
→
Σ
+
π
+
π
−
. Combining with the world average branching fraction of
$$ {\Lambda}_c^{+} $$
Λ
c
+
→
Σ
+
π
+
π
−
, their branching fractions are measured to be (0
.
377
±
0
.
042
±
0
.
020
±
0
.
021)% for
$$ {\Lambda}_c^{+} $$
Λ
c
+
→
Σ
+
K
+
K
−
, (0
.
200
±
0
.
023
±
0
.
011
±
0
.
011)% for
$$ {\Lambda}_c^{+} $$
Λ
c
+
→
Σ
+
K
+
π
−
, (0
.
414
±
0
.
080
±
0
.
030
±
0
.
023)% for
$$ {\Lambda}_c^{+} $$
Λ
c
+
→
Σ
+
ϕ
and (0
.
197
±
0
.
036
±
0
.
009
±
0
.
011)% for
$$ {\Lambda}_c^{+} $$
Λ
c
+
→ Σ
+
K
+
K
−
(non-
ϕ
). In all the above results, the first uncertainties are statistical, the second are systematic and the third are from external input of the branching fraction of
$$ {\Lambda}_c^{+} $$
Λ
c
+
→
Σ
+
π
+
π
−
. Since no signal for
$$ {\Lambda}_c^{+} $$
Λ
c
+
→
Σ
+
K
+
π
−
π
0
is observed, the upper limit of its branching fraction is determined to be 0.13% at the 90% confidence level.
Using an e thorn e- collision data sample with a total integrated luminosity of 3.19 fb-1 collected with the BESIII detector at a center-of-mass energy of 4.178 GeV, the branching fraction of the ...inclusive decay of the D thorn s meson to final states including at least three charged pions is measured for the first time to be BoD thorn s & RARR; & pi; thorn & pi; thorn & pi;-X thorn 1/4 o32.81 â 0.35stat â 0.63syst thorn %. In this measurement the charged pions from K0S meson decays are excluded. The partial branching fractions of D thorn s & RARR;& pi; thorn & pi; thorn & pi;-X are also measured as a function of the & pi; thorn & pi; thorn & pi;- invariant mass.
Using (10.087±0.044)×109 J/ψ events collected by the Beijing Spectrum III (BESIII) detector at the Beijing Electron Positron Collider II (BEPCII) collider, we search for the hyperon semileptonic ...decay ... . No significant signal is observed and the upper limit on the branching fraction ... is set to be 2.59×10−4 at 90% confidence level. This result is one order of magnitude more strict than the previous best limit.(ProQuest: … denotes formulae omitted.)
Using o1.0087 similar to 0.0044THORN x 1010 J=. events collected by the BESIII detector at the BEPCII collider, we report the first search for the baryon and lepton number violating decays.0. ...K-ethorn with.oB - LTHORN 1/4 0 and.0. Kthorne- with j.oB - LTHORNj 1/4 2, where B (L) is the baryon (lepton) number. While no signal is observed, the upper limits on the branching fractions of these two decays are set to Bo.0. K-ethornTHORN < 3.6 x 10- 6 and Bo.0. Kthorne- THORN < 1.9 x 10- 6 at the 90% confidence level, respectively. These results offer a direct probe of baryon number violating interactions involving a strange quark.
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