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.
Pieces (5 × 5 × 5mm) of woody material were removed and soaked in 2% NaOCl for one minute, followed by two one-minute distilled water washes. After surface sterilising with 70% ethanol, a stem wound ...was made using a sterile 6 mm cork borer, 10 cm above soil level. TABLE 1 Results of Gnomoniopsis smithogilvyi pathogenicity trial Isolate used/control Number of plants inoculated Mean vertical lesion length G. smithogilvyi reisolated 21-0214 26 9.5 Yes 21-0489 26 12 Yes Control 8 0 No FIGURE 3.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
.
The HADES data from p + Nb collisions at a center-of-mass energy of
GeV are analyzed employing a statistical hadronization model. The model can successfully describe the production yields of the ...identified hadrons
,
,
,
K
0
s
,
with parameters
MeV and
MeV, which fit well into the chemical freeze-out systematics found in heavy-ion collisions. In addition, we reanalyze our previous HADES data from Ar + KCl collisions at
GeV with an updated version of the model. We address equilibration in heavy-ion collisions by testing two aspects: the description of yields and the regularity of freeze-out parameters from a statistical model fit as a function of colliding energy and system size. Despite its success, the model fails to describe the observed
yields in both, p + Nb and Ar + KCl . Special emphasis is put on feed-down contributions from higher-lying resonance states as a possible explanation for the observed excess.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
BESIII Latest Results Destefanis, M.
Nuclear and particle physics proceedings,
October-December 2018, 2018-10-00, Volume:
303-305
Journal Article
Peer reviewed
Since 2009 the BESIII spectrometer, which operates at the IHEP of Beijing, China, collected the world largest data sample of J/ψ, ψ(2S) and ψ(3770). Its excellent performances allowed to access a ...wide physics program, which includes deep investigation of the Standard Model, spectroscopy studies of the charmonium states, and search for new physics. An overview of the main experimental innovations and of the latest performed investigations will be here discussed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A
bstract
Using 10
.
1
×
10
9
J/ψ
events produced by the Beijing Electron Positron Collider (BEPCII) at a center-of-mass energy
s
= 3
.
097 GeV and collected with the BESIII detector, we present a ...search for the rare semi-leptonic decay
J/ψ → D
−
e
+
ν
e
+ c.c. No excess of signal above background is observed, and an upper limit on the branching fraction ℬ(
J
/
ψ
→
D
−
e
+
ν
e
+
c
.
c
.) < 7.1 × 10
−8
is obtained at 90% confidence level. This is an improvement of more than two orders of magnitude over the previous best limit.
The CGEM-IT readout chain Amoroso, A.; Baldini Ferroli, R.; Balossino, I. ...
Journal of instrumentation,
08/2021, Volume:
16, Issue:
8
Journal Article
Peer reviewed
Open access
An innovative Cylindrical Gas Electron Multiplier (CGEM) detector is under construction for the upgrade of the inner tracker of the BESIII experiment. A novel system has been worked out for the ...readout of the CGEM detector, including a new ASIC, dubbed TIGER -Torino Integrated GEM Electronics for Readout, designed for the amplification and digitization of the CGEM output signals. The data output by TIGER are collected and processed by a first FPGA-based module, GEM Read Out Card, in charge of configuration and control of the front-end ASICs. A second FPGA-based module, named GEM Data Concentrator, builds the trigger selected event packets containing the data and stores them via the main BESIII data acquisition system. The design of the electronics chain, including the power and signal distribution, will be presented together with its performance.
We report measurements of electron pair production in elementary p+p and d+p reactions at 1.25 GeV/u with the HADES spectrometer. For the first time, the electron pairs were reconstructed for n+p ...reactions by detecting the proton spectator from the deuteron breakup. We find that the yield of electron pairs with invariant mass Me+e−>0.15 GeV/c2 is about an order of magnitude larger in n+p reactions as compared to p+p. A comparison to model calculations demonstrates that the production mechanism is not sufficiently described yet. The electron pair spectra measured in C+C reactions are compatible with a superposition of elementary n+p and p+p collisions, leaving little room for additional electron pair sources in such light collision systems.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Abstract
A Cylindrical Gas Electron Multiplier (CGEM) is under construction for the upgrade of the BESIII inner tracker. A preliminary simulation of the CGEM signal before the frond-end electronics ...has been worked out by making some sampling models from the beforehand Garfield++ simulation. The electronics response functions are implemented making the simulation of CGEM more complete. By comparing the cosmic-ray data acquired by two layers of CGEM and the simulation, the micro-sector effect is simulated and some key parameters in the sampling models are fine tuned in this order: gain, charge sharing, charge fluctuation and electron diffusion. A general agreement is achieved between the cosmic-ray data and the simulation with these improvements.
The tagged quasi-free np→npπ+π− reaction has been studied experimentally with the High Acceptance Di-Electron Spectrometer (HADES) at GSI at a deuteron incident beam energy of 1.25 GeV/nucleon ...(s∼2.42 GeV/c for the quasi-free collision). For the first time, differential distributions of solid statistics for π+π− production in np collisions have been collected in the region corresponding to the large transverse momenta of the secondary particles. The invariant mass and angular distributions for the np→npπ+π− reaction are compared with different models. This comparison confirms the dominance of the t-channel with ΔΔ contribution. It also validates the changes previously introduced in the Valencia model to describe two-pion production data in other isospin channels, although some deviations are observed, especially for the π+π− invariant mass spectrum. The extracted total cross section is also in much better agreement with this model. Our new measurement puts useful constraints for the existence of the conjectured dibaryon resonance at mass M∼2.38 GeV and with width Γ∼70 MeV.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Performance of triple GEM prototypes in strong magnetic field has been evaluated by means of a muon beam at the H4 line of the SPS test area at CERN. Data have been reconstructed and analyzed offline ...with two reconstruction methods: the charge centroid and the micro-Time-Projection-Chamber exploiting the charge and the time measurement respectively. Depending on the combination of the particle incident angle and magnetic filed, there's always one of the two algorithms achieving a spatial resolution of 100–120 μm.
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