Measurement of the K-S ? Babusci, D.; Berlowski, M.; Bloise, C. ...
The journal of high energy physics,
02/2023
2
Journal Article
Recenzirano
Odprti dostop
The ratio R = gamma(K-S -> pi e nu)/gamma(KS -> pi(+)pi(-)) has been measured with a sample of 300 million KS mesons produced in phi -KLKS decays recorded by the KLOE experiment at the DA Phi ...NE e(+)e(-) collider. K-S -> pi e nu events are selected by a boosted decision tree built with kinematic variables and time-of-flight measurements. Data control samples of K-L -> pi e nu decays are used to evaluate signal selection efficiencies. With 49647 +/- 316 signal events we measure R = (1.0421 +/- 0.0066(stat) +/- 0.0075(syst)) x 10(-3). The combination with our previous measurement gives R = (1.0338 +/- 0.0054(stat) +/- 0.0064(syst)) x 10(-3). From this value we derive the branching fraction B(K-S -> pi e nu) = (7.153 +/- 0.037(stat)+/- 0.044(syst)) x 10(-4) and f(+)(0)|V-us| = 0.2170 +/- 0.009.
Tests of the T, CP and CPT symmetries in the neutral kaon system are performed by the direct comparison of the probabilities of a kaon transition process to its symmetry-conjugate. The exchange of in ...and out states required for a genuine test involving an antiunitary transformation implied by time-reversal is implemented exploiting the entanglement of K0K‾0 pairs produced at a ϕ-factory.
A data sample collected by the KLOE experiment at DAΦNE corresponding to an integrated luminosity of about 1.7 fb−1 is analysed to study the Δt distributions of the ϕ→KSKL→π+π−π±e∓ν and ϕ→KSKL→π±e∓ν3π0 processes, with Δt the difference of the kaon decay times. A comparison of the measured Δt distributions in the asymptotic region Δt≫τS allows to test for the first time T and CPT symmetries in kaon transitions with a precision of few percent, and to observe CP violation with this novel method.
A
bstract
The ratio
R
= Γ(
K
S
→ πeν
)
/
Γ(
K
S
→ π
+
π
−
) has been measured with a sample of 300 million
K
S
mesons produced in
ϕ → K
L
K
S
decays recorded by the KLOE experiment at the DAΦNE
e
+
e
...−
collider.
K
S
→ πeν
events are selected by a boosted decision tree built with kinematic variables and time-of-flight measurements. Data control samples of
K
L
→ πeν
decays are used to evaluate signal selection efficiencies. With 49647
±
316 signal events we measure
R
= (1
.
0421
±
0
.
0066
stat
±
0
.
0075
syst
)
×
10
−
3
. The combination with our previous measurement gives
R
= (1
.
0338
±
0
.
0054
stat
±
0
.
0064
syst
)
×
10
−
3
. From this value we derive the branching fraction
B
(
K
S
→ πeν
) = (7
.
153
±
0
.
037
stat
±
0
.
044
syst
)
×
10
−
4
and
f
+
(0)
|V
us
|
= 0
.
2170
±
0
.
009.
Tests of the T, CP and CPT symmetries in the neutral kaon system are performed by the direct comparison of the probabilities of a kaon transition process to its symmetry-conjugate. The exchange of in ...and out states required for a genuine test involving an anti-unitary transformation implied by time-reversal is implemented exploiting the entanglement of \(K^0\bar{K}{}^0\) pairs produced at a \(\phi\)-factory. A data sample collected by the KLOE experiment at DA\(\Phi\)NE corresponding to an integrated luminosity of about 1.7 fb\(^{-1}\) is analysed to study the \(\Delta\)t distributions of the \(\phi\to K_{S}K_{L}\to \pi^+\pi^- \: \pi^{\pm}e^{\mp}\nu\) and \(\phi\to K_{S}K_{L}\to \pi^{\pm}e^{\mp}\nu \: 3\pi^0\) processes, with \(\Delta\)t the difference of the kaon decay times. A comparison of the measured \(\Delta\)t distributions in the asymptotic region \(\Delta t \gg \tau_{S}\) allows to test for the first time T and CPT symmetries in kaon transitions with a precision of few percent, and to observe CP violation with this novel method.
The branching fraction for the decay $K_S \to \pi e \nu$ has been measured
with a sample of 300 million $K_S$ mesons produced in $\phi \to K_L K_S$ decays
recorded by the KLOE experiment at the ...DA$\Phi$NE $e^+e^-$ collider. Signal
decays are selected by a boosted decision tree built with kinematic variables
and time-of-flight measurements. Data control samples of $K_L \to \pi e \nu$
decays are used to evaluate signal selection efficiencies. A fit to the
reconstructed electron mass distribution finds 49647$\pm$316 signal events.
Normalising to the $K_S \to \pi^+\pi^-$ decay events the result for the
branching fraction is $\mathcal{B}(K_S \to \pi e \nu) = (7.211 \pm 0.046_{\rm
stat} \pm 0.052_{\rm syst}) \times10^{-4}$. The combination with our previous
measurement gives $\mathcal{B}(K_S \to \pi e \nu) = (7.153 \pm 0.037_{\rm stat}
\pm 0.043_{\rm syst}) \times10^{-4}$. From this value we derive $f_+(0)|V_{us}|
= 0.2170 \pm 0.009$.
The branching fraction for the decay \(K_S \to \pi e \nu\) has been measured with a sample of 300 million \(K_S\) mesons produced in \(\phi \to K_L K_S\) decays recorded by the KLOE experiment at the ...DA\(\Phi\)NE \(e^+e^-\) collider. Signal decays are selected by a boosted decision tree built with kinematic variables and time-of-flight measurements. Data control samples of \(K_L \to \pi e \nu\) decays are used to evaluate signal selection efficiencies. A fit to the reconstructed electron mass distribution finds 49647\(\pm\)316 signal events. Normalising to the \(K_S \to \pi^+\pi^-\) decay events the result for the branching fraction is \(\mathcal{B}(K_S \to \pi e \nu) = (7.211 \pm 0.046_{\rm stat} \pm 0.052_{\rm syst}) \times10^{-4}\). The combination with our previous measurement gives \(\mathcal{B}(K_S \to \pi e \nu) = (7.153 \pm 0.037_{\rm stat} \pm 0.043_{\rm syst}) \times10^{-4}\). From this value we derive \(f_+(0)|V_{us}| = 0.2170 \pm 0.009\).
In this paper, we present an alternative approach to neuromorphic systems based on multilevel resistive memory synapses and deterministic learning rules. We demonstrate an original methodology to use ...conductive-bridge RAM (CBRAM) devices as, easy to program and low-power, binary synapses with stochastic learning rules. New circuit architecture, programming strategy, and probabilistic spike-timing dependent plasticity (STDP) learning rule for two different CBRAM configurations with-selector (1T-1R) and without-selector (1R) are proposed. We show two methods (intrinsic and extrinsic) for implementing probabilistic STDP rules. Fully unsupervised learning with binary synapses is illustrated through two example applications: 1) real-time auditory pattern extraction (inspired from a 64-channel silicon cochlea emulator); and 2) visual pattern extraction (inspired from the processing inside visual cortex). High accuracy (audio pattern sensitivity > 2, video detection rate > 95%) and low synaptic-power dissipation (audio 0.55 μW, video 74.2 μW) are shown. The robustness and impact of synaptic parameter variability on system performance are also analyzed.
PDF