Slow resonant extraction from the synchrotron makes it possible to provide relatively stable beams for a long time. The principle of slow extraction is intentionally exciting the third-order ...resonance by controlling detuning and sextupole strength with the gradual release of particles from inside to outside a stable separatrix. The Budker Institute of Nuclear Physics (BINP) develops the ion synchrotron for a wide range of technological applications. This paper describes slow resonant extraction from an ion synchrotron with betatron oscillation excitation by a transverse RF field.
A
bstract
The cross section of the process
e
+
e
−
→ ηπ
+
π
−
is measured using the data collected with the CMD-3 detector at the VEPP-2000 collider in the center-of-mass energy range from 1
.
1 to 2
....
0 GeV. The decay mode
η → γγ
is used for
η
meson reconstruction in the data sample corresponding to an integrated luminosity of 78
.
3 pb
−
1
. The energy dependence of the
e
+
e
−
→ ηπ
+
π
−
cross section is fitted within the framework of vector meson dominance in order to extract the Γ(
ρ
(1450)
→ e
+
e
−
)
B
(
ρ
(1450)
→ ηπ
+
π
−
) and the Γ(
ρ
(1700)
→ e
+
e
−
)
B
(
ρ
(1700)
→ ηπ
+
π
−
) products. Based on conservation of vector current, the analyzed data are used to test the relationship between the
e
+
e
−
→ ηπ
+
π
−
cross section and the spectral function in
τ
−
→ ηπ
−
π
0
ντ
decay. The
e
+
e
−
→ ηπ
+
π
−
cross section obtained with the CMD-3 detector is in good agreement with the previous measurements.
Nuclotron based Ion Collider fAcility (NICA) project is in progress at the Joint Institute for Nuclear Research and will start experiments with heavy ions. In the context of the NICA hadronic physics ...programme double polarized
-,
- and
-collisions even at lower energies of
GeV, which will be accessible already at the initial stage of experiments,are essential tools for precise studying the spin dependence of the nucleon–nucleon strong interactions, in both elastic and deep-inelastic regimes. A special interest is interaction in few baryon systems at double strangeness, charm and beauty thresholds.For instance, polarized large-angle elastic
and
scattering near the charm threshold allows one to get an access to properties of possible exotic multiquark states and their relation to the states recently observed at LHCb.Large angle scattering of protons and deuterons on the deuteron contains unique information on the short-range structure of the deuteron, its nonnucleonic degrees of freedom and also on color transparency phenomenon. Furthermore, double polarized proton–deuteron scattering offer a possibility to test the Standard Model through the search for time-invariance (or CP-invariance under CPT symmetry) violation and parity-violation in single-polarized scattering. This paper contains suggestions for experiments with usage of the Spin Physics Detector (SPD) and discusses perspectives of the first stage of the SPD Programme. This includes experiments with nonpolarized beams too as well as collisions like
12
С–
12
С and
40
Сa–
40
Ca.
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
The process
e
+
e
-
→
n
n
¯
is studied in the experiment at the VEPP-2000
e
+
e
-
collider with the SND detector. The technique of the time measurements in the multichannel NaI(Tl) electromagnetic ...calorimeter is used to select
n
n
¯
events. The value of the measured cross section in the center-of-mass energy range from 1.894 to 2 GeV varies from 0.5 to 0.35 nb. The effective neutron timelike form factor is derived from the measured cross section and compared with the proton form factor. The ratio of the neutron electric and magnetic form factors is obtained from the analysis of the antineutron polar angle distribution and found to be consistent with unity.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
To describe outcome after pancreatic surgery in the first 6 years of a mandatory nationwide audit.
Within the Dutch Pancreatic Cancer Group, efforts have been made to improve outcome after pancreatic ...surgery. These include collaborative projects, clinical auditing, and implementation of an algorithm for early recognition and management of postoperative complications. However, nationwide changes in outcome over time have not yet been described.
This nationwide cohort study included consecutive patients after pancreatoduodenectomy (PD) and distal pancreatectomy from the mandatory Dutch Pancreatic Cancer Audit (January 2014-December 2019). Patient, tumor, and treatment characteristics were compared between 3 time periods (2014-2015, 2016-2017, and 2018-2019). Short-term surgical outcome was investigated using multilevel multivariable logistic regression analyses. Primary endpoints were failure to rescue (FTR) and in-hospital mortality.
Overall, 5345 patients were included, of whom 4227 after PD and 1118 after distal pancreatectomy. After PD, FTR improved from 13% to 7.4% odds ratio (OR) 0.64, 95% confidence interval (CI) 0.50-0.80, P <0.001 and in-hospital mortality decreased from 4.1% to 2.4% (OR 0.68, 95% CI 0.54-0.86, P =0.001), despite operating on more patients with age >75 years (18%-22%, P =0.006), American Society of Anesthesiologists score ≥3 (19%-31%, P <0.001) and Charlson comorbidity score ≥2 (24%-34%, P <0.001). The rates of textbook outcome (57%-55%, P =0.283) and major complications remained stable (31%-33%, P =0.207), whereas complication-related intensive care admission decreased (13%-9%, P =0.002). After distal pancreatectomy, improvements in FTR from 8.8% to 5.9% (OR 0.65, 95% CI 0.30-1.37, P =0.253) and in-hospital mortality from 1.6% to 1.3% (OR 0.88, 95% CI 0.45-1.72, P =0.711) were not statistically significant.
During the first 6 years of a nationwide audit, in-hospital mortality and FTR after PD improved despite operating on more high-risk patients. Several collaborative efforts may have contributed to these improvements.
A cross section of the process e+e−→π+π−π+π− has been measured using 6798±93 signal events from a data sample corresponding to an integrated luminosity of 9.8 pb−1 collected with the CMD-3 detector ...in the center-of-mass energy range 920–1060 MeV. The measured cross section exhibits a pattern of interference of the ϕ(1020)→π+π−π+π− decay with a non-resonant process e+e−→π+π−π+π−, from which we obtain the branching fraction of the doubly suppressed decays (by G-parity and OZI rule): B(ϕ→π+π−π+π−)=(6.5±2.7±1.6)×10−6.
We analyze a 37 pb−1 data sample collected with the SND detector at the VEPP-2000 e+e− collider in the center-of-mass energy range 1.05–2.00 GeV and present an updated measurement of the ...e+e−→ωπ0→π0π0γ cross section. In particular, we correct the mistake in radiative correction calculation made in our previous measurement based on a part of the data. The measured cross section is fitted with the vector meson dominance model with three ρ-like states and used to test the conserved vector current hypothesis in the τ−→ωπ−ντ decay.
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.
We present a measurement of the pion form factor based on e+e− annihilation data from the CMD-2 detector in the energy range 0.6<s<1.0 GeV with a systematic uncertainty of 0.8%. A data sample is five ...times larger than that used in our previous measurement.
PDF
