Crucial inputs for a variety of $\textit{CP}$-violation studies can be determined through the analysis of pairs of quantum-entangled neutral $\textit{D}$ mesons, which are produced in the decay of ...the $_ψ$(3770) resonance. The relative strong-phase parameters between $D^0$ and $\bar{D}^0$ in the decays $D^0 → K^0_{S,L}π^+π^–$ are studied using 2.93 fb$^{–1}$ of $e^+e^–$ annihilation data delivered by the BEPCII collider and collected by the BESIII detector at a center-of-mass energy of 3.773 GeV. Results are presented in regions of the phase space of the decay. These are the most precise measurements to date of the strong-phase parameters in $D → K^0_{S,L}π^+π^–$ decays. Using these parameters, the associated uncertainty on the Cabibbo-Kobayashi-Maskawa angle $γ/\phi_3$ is expected to be between 0.7° and 1.2° for an analysis using the decay $B^± → D K^±, D → K^0_Sπ^+π^–$, where $\textit{D}$ represents a superposition of $D^0$ and $\bar{D}^0$ states. This is a factor of 3 smaller than that achievable with previous measurements. Furthermore, these results provide valuable input for charm-mixing studies, other measurements of $\textit{CP}$ violation, and the measurement of strong-phase parameters for other $\textit{D}$-decay modes.
Using a sample of 1.31×109 J/ψ events collected with the BESIII detector at the BEPCII collider, we study the decays of J/ψ→KSKL and KSKS. The branching fraction of J/ψ→KSKL is determined to be ...B(J/ψ→KSKL)=(1.93±0.01(stat)±0.05(syst))×10−4, which significantly improves on previous measurements. No clear signal is observed for the J/ψ→KSKS process, and the upper limit at the 95% confidence level for its branching fraction is determined to be B(J/ψ→KSKS)<1.4×10−8, which improves on the previous searches by 2 orders in magnitude and reaches the order of the Einstein-Podolsky-Rosen expectation.
Using e+e− collision data corresponding to an integrated luminosity of 2.93 fb−1 taken at a center-of-mass energy of 3.773 GeV with the BESIII detector, we determine the absolute branching fractions ...B(D+→KS0K+)=(3.02±0.09±0.08)×10−3, B(D+→KS0K+π0)=(5.07±0.19±0.23)×10−3, B(D+→KL0K+)=(3.21±0.11±0.11)×10−3, and B(D+→KL0K+π0)=(5.24±0.22±0.22)×10−3, where the first and second uncertainties are statistical and systematic, respectively. The branching fraction B(D+→KS0K+) is consistent with the world average value and the other three branching fractions are measured for the first time. We also measure the CP asymmetries for the four decays and do not find a significant deviation from zero.
Abstract
Using a sample of
$$1.31\times 10^{9} ~J/\psi $$
1.31
×
10
9
J
/
ψ
events collected with the BESIII detector, we perform a study of
$$J/\psi \rightarrow \gamma K{\bar{K}}\eta '$$
J
/
ψ
→
γ
K
...K
¯
η
′
.
X
(2370) is observed in the
$$K{\bar{K}}\eta '$$
K
K
¯
η
′
invariant-mass distribution with a statistical significance of
$$8.3\sigma $$
8.3
σ
. Its resonance parameters are measured to be
$$M=2341.6\pm 6.5 \, \text {(stat.)} \pm 5.7 \, \text {(syst.)}~ \hbox {MeV}/c^{2}$$
M
=
2341.6
±
6.5
(stat.)
±
5.7
(syst.)
MeV
/
c
2
and
$$\Gamma = 117\pm 10 \, \text {(stat.)}\pm 8 \, \text {(syst.)}~\hbox {MeV}$$
Γ
=
117
±
10
(stat.)
±
8
(syst.)
MeV
. The product branching fractions for
$$J/\psi \rightarrow \gamma X(2370),X(2370)\rightarrow K^{+}K^{-}\eta '$$
J
/
ψ
→
γ
X
(
2370
)
,
X
(
2370
)
→
K
+
K
-
η
′
and
$$J/\psi \rightarrow \gamma X(2370),X(2370)\rightarrow K_{S}^{0}K_{S}^{0}\eta '$$
J
/
ψ
→
γ
X
(
2370
)
,
X
(
2370
)
→
K
S
0
K
S
0
η
′
are determined to be
$$(1.79\pm 0.23\, \text {(stat.)}\pm 0.65\,\text {(syst.)})\times 10^{-5}$$
(
1.79
±
0.23
(stat.)
±
0.65
(syst.)
)
×
10
-
5
and
$$(1.18\pm 0.32\, \text {(stat.)}\pm 0.39\, \text {(syst.)})\times 10^{-5}$$
(
1.18
±
0.32
(stat.)
±
0.39
(syst.)
)
×
10
-
5
, respectively. No evident signal for
X
(2120) is observed in the
$$K{\bar{K}}\eta '$$
K
K
¯
η
′
invariant-mass distribution. The upper limits for the product branching fractions of
$${\mathcal {B}}(J/\psi \rightarrow \gamma X(2120)\rightarrow \gamma K^{+} K^{-} \eta ')$$
B
(
J
/
ψ
→
γ
X
(
2120
)
→
γ
K
+
K
-
η
′
)
and
$${\mathcal {B}}(J/\psi \rightarrow \gamma X(2120)\rightarrow \gamma K_{S}^{0} K_{S}^{0} \eta ')$$
B
(
J
/
ψ
→
γ
X
(
2120
)
→
γ
K
S
0
K
S
0
η
′
)
are determined to be
$$1.49\times 10^{-5}$$
1.49
×
10
-
5
and
$$6.38\times 10^{-6}$$
6.38
×
10
-
6
at the 90% confidence level, respectively.
One of the most important goals of modern nuclear physics is to contruct nuclear force model which properly describes the experimental data. To develop and test predictions of current models the ...breakup super(1)H(d,p p)n reaction was investigated experimentally at 100 and 130 MeV deuteron beam energies. Rich set of data for cross section, vector and tensor analyzing powers was obtained with the use of the SALAD and BINA detectors at KVI and Germanium Wall setup at FZ-Julich. Results are compared with various theoretical approaches which describe the three-nucleon (3N) system dynamics. For correct description of the cross section data both, three-nucleon force (3NF) and Coulomb force, have to be included into calculations and influence of those ingredients is seizable at specific parts of the phase space. In case of the vector analyzing powers very low sensitivity to any effects beyond nucleon-nucleon interaction was found. At 130 MeV, the Axy data are not correctly described when 3NF models are included into calculations.
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