The fast scintillation crystals such as pure CsI or LYSO(Ce) today are considered for timing measurements in future colliding beam experiments. The aim of such counters is to determine time of ...particles arrival with accuracy better than 100 ps. The work is devoted to investigation of influence of Cherenkov radiation on the time resolution of the detectors based on LYSO(Ce) crystals. The results of MC simulation and beam test are presented.
The Super Charm-Tau Factory is an electron-positron collider project in Novosibirsk with a peak luminosity of 1035cm−1s−1 operating in the center of mass energy range between 2 and 6 GeV. The physics ...program of the experiment in general is devoted to the study of charm quark and tau lepton. Conceptual designs of the collider and a universal detector are presented. The dedicated particle identification (PID) system is required to provide the state-of-the-art level of μ/π separation for the particle momenta up to 1.2GeV/c. The following options for the PID system are considered in this paper: Focusing Aerogel RICH (FARICH) detector composed of 4-layer aerogel tiles, threshold Cherenkov counters based on aerogel and shifter (ASHIPH), Focusing DIRC (FDIRC) counter and time-of-flight (ToF) detector combined with the time-of-propagation (ToP) approach providing a time resolution better than 30ps. Also the capabilities of particles separation in tracking system are discussed. Comparison of PID approaches with help of parametric simulation is performed.
A
bstract
The cross section of the process
e
+
e
−
→
π
+
π
−
has been measured in the Spherical Neutral Detector (SND) experiment at the VEPP-2000
e
+
e
−
collider VEPP-2000 in the energy region 525
...<
s
<
883 MeV. The measurement is based on data with an integrated luminosity of about 4.6 pb
−
1
. The systematic uncertainty of the cross section determination is 0.8% at
s
>
0
.
600 GeV. The
ρ
meson parameters are obtained as
m
ρ
= 775
.
3 ± 0
.
5 ± 0
.
6 MeV, Γ
ρ
= 145
.
6 ± 0
.
6 ± 0
.
8 MeV,
B
ρ
→
e
+
e−
×
B
ρ
→
π
+
π−
= (4
.
89 ± 0
.
02 ± 0
.
04) × 10
−
5
, and the parameters of the
e
+
e
−
→
ω
→
π
+
π
−
process, suppressed by
G
-parity, as
B
ω
→
e
+
e−
×
B
ω
→
π
+
π−
= (1
.
32 ± 0
.
06 ± 0
.
02) × 10
−
6
and and
ϕ
ρω
= 110
.
7 ± 1
.
5 ± 1
.
0 degrees.
Results are presented from measuring the
cross section and effective neutron timelike form factor. Data are collected in 2020–2021 at the VEPP-2000
collider in the 1891 to 2007 MeV center-of-mass ...range of energies. The general purpose nonmagnetic SND detector is used to detect neutron–antineutron events. The time-of-flight approach is used to select
events. The measured cross section is 0.4–0.6 nbn. The neutron form factor in the investigated range of energies varies from 0.3 to 0.2.
The cross section for the process
e
+
e
−
→
ηK
+
K
−
wasmeasured at c.m. energies in the range between 1.56 and 2.00 GeV in an experiment with the SND detector at the VEPP-2000
e
+
e
−
collider. The ...invariant-mass distribution of kaon pairs is consistent with the hypothesis that the transition through the
ηφ
intermediate state makes a dominant contribution to the transition in question.
The process
e
+
e
-
→
η
η
γ
is studied in the center-of-mass energy range 1.17–2.00 GeV using data with an integrated luminosity of 201 pb
-
1
collected by the SND detector at the VEPP-2000
e
+
e
-
...collider. The
e
+
e
-
→
η
η
γ
cross section is measured for the first time. It is shown that the dominant mechanism of this reaction is the transition through the
ϕ
η
intermediate state. Our result on the
e
+
e
-
→
η
η
γ
cross section is consistent with the
e
+
e
-
→
ϕ
η
measurement in the
ϕ
→
K
+
K
-
mode. The search for radiative processes contributing to the
e
+
e
-
→
η
η
γ
cross section is performed, and no significant signal is observed.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Search for the process e + e − → η Achasov, M. N.; Barnyakov, A. Yu; Beloborodov, K. I. ...
Physical review. D,
09/2018, Letnik:
98, Številka:
5
Journal Article
Recenzirano
Odprti dostop
A search for the rare decay η→e+e− is performed using the inverse process e+e−→η in the decay mode η→π0π0π0. We analyze data with an integrated luminosity of 654 nb−1 accumulated at the VEPP-2000 ...e+e− collider with the SND detector at the center-of-mass energy E=mηc2≈548 MeV, and set the upper limit B(η→e+e−)<7×10−7 at the 90% confidence level.
Abstract The process $$e^+e^-\rightarrow K^+K^-\pi ^0$$ e + e - → K + K - π 0 is studied with the SND detector at the VEPP-2000 $$e^+e^-$$ e + e - collider. Basing on data with an integrated ...luminosity of 26.4 $$\hbox {pb}^{-1}$$ pb - 1 we measure the $$e^+e^-\rightarrow K^+K^-\pi ^0$$ e + e - → K + K - π 0 cross section in the center-of-mass energy range from 1.28 up to 2 GeV. The measured mass spectrum of the $$K\pi $$ K π system indicates that the dominant mechanism of this reaction is the transition through the $$K^{*}(892)K$$ K ∗ ( 892 ) K intermediate state. The cross section for the $$\phi \pi ^0$$ ϕ π 0 intermediate state is measured separately. The SND results are consistent with previous measurements in the BABAR experiment and have comparable accuracy. We study the effect of the interference between the $$\phi \pi ^0$$ ϕ π 0 and $$K^*K$$ K ∗ K amplitudes. It is found that the interference gives sizable contribution to the measured $$e^+e^- \rightarrow \phi \pi ^0\rightarrow K^+K^-\pi ^0$$ e + e - → ϕ π 0 → K + K - π 0 cross section below 1.7 GeV.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract
The process
$$e^+e^-\rightarrow K^+K^-\pi ^0$$
e
+
e
-
→
K
+
K
-
π
0
is studied with the SND detector at the VEPP-2000
$$e^+e^-$$
e
+
e
-
collider. Basing on data with an integrated ...luminosity of 26.4
$$\hbox {pb}^{-1}$$
pb
-
1
we measure the
$$e^+e^-\rightarrow K^+K^-\pi ^0$$
e
+
e
-
→
K
+
K
-
π
0
cross section in the center-of-mass energy range from 1.28 up to 2 GeV. The measured mass spectrum of the
$$K\pi $$
K
π
system indicates that the dominant mechanism of this reaction is the transition through the
$$K^{*}(892)K$$
K
∗
(
892
)
K
intermediate state. The cross section for the
$$\phi \pi ^0$$
ϕ
π
0
intermediate state is measured separately. The SND results are consistent with previous measurements in the BABAR experiment and have comparable accuracy. We study the effect of the interference between the
$$\phi \pi ^0$$
ϕ
π
0
and
$$K^*K$$
K
∗
K
amplitudes. It is found that the interference gives sizable contribution to the measured
$$e^+e^- \rightarrow \phi \pi ^0\rightarrow K^+K^-\pi ^0$$
e
+
e
-
→
ϕ
π
0
→
K
+
K
-
π
0
cross section below 1.7 GeV.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
PDF
