The cross section of the process e+ e−→ KS KL π0 has been studied with the CMD-3 detector at the VEPP-2000 electron-positron collider in the center-of-mass energy range from 1.1 to 2 GeV. Preliminary ...results on the total cross section of the process are presented.
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.
A large amount of data collected with the CMD-3 detector above the threshold of the
nn
̅pair allows to measure the cross section of the process
e
+
e
−
→
nn
̅and the neutron form factor with good ...accuracy. This task is complicated by a large number of background events and necessity of finding ways to suppress them. A technique of identification for
e
+
e
−
→
nn
̅events is described.
Experimental input from $e^+e^-$ machines to hadronic contribution to muon (g-2) M. N. Achasov, R. R. Akhmetshin, A. N. Amirkhanov, A. V. Anisenkov, V. M. Aulchenko, V. Sh. Banzarov, A. Yu. Barnyakov, N. S. Bashtovoy, K. I. Beloborodov, A. V. Berdyugin, D. E. Berkaev, A. G. Bogdanchikov, A. E. Bondar, A. A. Botov, A. V. Bragin, T. V. Dimova, V. P. Druzhinin, S. I. Eidelman, D. A. Epifanov, L. B. Epshteyn, A. L. Erofeev, G. V. Fedotovich, S. E. Gayazov, V. B. Golubev, A. A. Grebenuk, S. S. Gribanov, D. N. Grigoriev, F. V. Ignatov, V. L. Ivanov, L. V. Kardapoltsev, S. V. Karpov, V. F. Kazanin, A. G. Kharlamov, A. N. Kirpotin, I. A. Koop, A. A. Korol, A. A. Korobov, S. V. Koshuba, A. N. Kozyrev, E. A. Kozyrev, D. P. Kovrizhin, P. P. Krokovny, A. S. Kupich, A. E. Kuzmenko, A. S. Kuzmin, R. A. Litvinov, I. B. Logashenko, P. A. Lukin, K. A. Martin, N. A. Melnikova, K. Yu. Mikhailov, A. E. Obrazovsky, V. S. Okhapkin, A. V. Otboev, E. V. Pakhtusova, Yu. N. Pestov, A. S. Popov, K. V. Pugachev, G. P. Razuvaev, A. A. Ruban, N. M. Ryskulov, A. E. Ryzhenenkov, A. I. Senchenko, S. I. Serednyakov, Yu. M. Shatunov, P. Yu. Shatunov, V. E. Shebalin, D. N. Shemyakin, D. A. Shtol, B. A. Shwartz, D. B. Shwartz, A. L. Sibidanov, Z. K. Silagadze, E. P. Solodov, I. K. Surin, A. A. Talyshev, V. M. Titov, S. S. Tolmachev, A. I. Vorobiov, I. M. Zemlyansky, Yu. V. Yudin
SciPost physics proceedings,
02/2019
1
Journal Article
Peer reviewed
Open access
Precise study of the hadrons production in $e^+e^-$ annihilation at low energies provides important information about interactions of light quarks and spectroscopy of their bound states. These ...studies are especially important for theoretical calculations of the muon $(g-2)$ via the Standard Model because of the present difference between theoretical and experimental values exceeds three standard deviations. In this report we will discuss current status and recent results obtained by the CMD-3 experiment and will give a brief look to status of the BaBar and Belle II experiments.
The process e+ e−→ K+ K−π0 has been studied in the center-of-mass energy range from 1.2 to 2 GeV using a 80.6 pb−1 data sample collected with the CMD-3 detector at the electron-positron collider ...VEPP-2000. Preliminary results of the cross-section measurement are presented.
The photovoltaic and photoconductive properties of film composites of a copolymer of styrene with octyl methacrylate and additions of the monomer ...(Z)-2-(4-methylthiazol-2-yl)-2-(pyrrolidin-2-ylidene)acetonitrile (HL) and complexes of NiL
2
, CoL
2
, and CuL
2
were investigated. It was established that these composites have hole-type photoconductivity while the inner photoeffect is determined by photogeneration of charge carriers from the HL monomers and by transport of nonequilibrium charge carriers among these monomers. The photovoltaic response increases with the metal complexes in the following order: CuL
2
, NiL
2
, CoL
2
.
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•The spectroscopic data are essential for the use of the theoretical model.•The energy gap between the ligand and Yb excited states is large.•The theoretical model shed light on the ...ligand-to-Yb energy transfer phenomenon.•The theoretical model used allows to estimate the quantum yield of the Yb emission.•The charge transfer state plays an important role in the energy transfer process.
We present the experimental and theoretical results that made it possible to propose the energy transfer mechanism for a Yb complex with a large energy gap between the ligand and Yb excited states using a theoretical model and experimental data. Absorption and emission spectroscopy in the 300–4 K range is used for the study of the Yb3+ compound with N-phosphorylated sulfonamide (NaYbL4), which, despite the large energy gap, is characterized by high emission sensitization efficiency (ηsens = 40%) and relatively long Yb3+ emission lifetime (27 μs). The crystal structure of NaYbL4, radiative lifetime (930 μs), refractive index (1.46), intrinsic (3.0%), and overall (1.3%) emission quantum yield were determined. To obtain the electronic properties of the NaYbL4, a time-dependent density functional theory (TD-DFT) was performed. The intramolecular energy transfer (IET) rates from the excited states S1 and T1 to the Yb3+ ion as well as between the ligand and the ligand-to-metal charge transfer (LMCT) states were calculated. Once the intersystem crossing S1 → T1 is not so effective due to a large energy gap between S1 and T1 (≈10000 cm−1), it has been shown that the LMCT state acts as an additional channel to feed the T1 state. Then, the T1 can transfer energy to the Yb3+ 2F5/2 energy level (WT), where WT is dominated by the exchange mechanism. Based on IET and a rate equation model, the overall emission quantum yield QLLn was simulated with and without the LMCT, this also confirmed that the pathway S1 → LMCT → T1 → Yb3+ is more likely than the S1 → T1 → Yb3+ one.
Glukhovskoi discuss the modifiers of n-butyllithium in the synthesis of polybutadiene and styrene-butadiene rubbers. Two industrial processes are being employed to produce styrene-butadiene rubbers ...and polybutadiene with the use of an n-butyllithium + modifier catalytic system. The developed modifiers of n-butyllithium comprise mixed alcoholates of alkali and alkaline earth metals. The alcohol modifiers chosen were high-boiling alcohols such as tetra(oxypropyl)ethylenediamine (Lapramol-294), alkylaminodiethanol, and tetrahydrofurfuryl alcohol. The choice of high-boiling alcohols is governed by the fact that, when the alcoholates break down during aqueous degassing of the polymers, they do not enter the return solvent and hardly enter the waste waters. Lithium, sodium, potassium, magnesium, and calcium are used as the metallic component of the alcoholates.
Since December 2010 the CMD-3 and SND detectors detectors collect data at the VEPP-2000 electron-positron collider. In 2013-2015 the injection facility of the collider has undergone an upgrade of the ...injection system. The new BINP injection complex has been connected to the VEPP-2000 collider, so the restrictions connected to the lack of positrons and limited beam energy transfer do not apply any more. The collider luminosity in whole energy range is restricted now only by beam-beam effects. VEPP-2000 collider started to collect data with two detectors at 2016 year. The collected data sample since 2010 corresponds more than 100 pb
-1
of integrated luminosity per detector in the c.m. energy between 0.32 and 2GeV. We will report here results of analysis of various hadronic cross sections from detectors both published and preliminary. These measurements are important by themselves and also because of the implications for anomaly of the magnetic moment of a muon (g-2) discrepancy.
We have studied the antimicrobial and hemolytic activity of synthetic antimicrobial peptides (SAMPs), i.e., Arg
9
Phe
2
(
P1
-Arg), Lys
9
Phe
2
(
P2
-Lys), and His
9
Phe
2
(
P3
-His), which have a ...“linear” type of amphipathicity and contain the cationic amino acid residues of arginine, lysine, or histidine. In this study, we have used various pathogenic microorganism strains of gram-negative bacteria (
Pseudomonas aeruginosa
,
Escherichia coli,
and
Salmonella enterica
)
,
gram-positive bacteria (
Staphylococcus aureus
), and the conditionally pathogenic yeast fungus (
Candida albicans
)
.
It has been shown that the replacement of the arginine residues by lysine or histidine residues in the tested SAMPs significantly degrades their antibacterial properties in the series:
P1
-Arg >
P2
-Lys
P3
-His. The cationic analog of SAMP,
P1
-Arg, has the highest antibacterial activity (MIC
50
= 43–76 μM), while peptide
P3
-His does not exhibit this activity (MIC
50
> 100 μM). The
P1
-Arg and
P2
-Lys peptides were 6–10 times more active against the opportunistic fungus
C. albicans
(MIC
50
6.7 and 10.9 μM, respectively) and the
P3
-His peptide has 100-times increased antimycotic activity (MIC
50
0.6 μM) compared with their effect on bacterial cells. All of the tested peptides with the linear type of amphipathicity and low hydrophobicity, i.e.,
P1
-Arg,
P2
-Lys, and
P3
-His, that contain only two Phe residues regardless of the presence of cationic amino acids (Arg, Lys, or His) exhibit a relatively low hemolytic activity (not more than 4% hemolysis at 1000 μM peptide concentration). Thus, considering the same synthesis efficiency (56–63%) and approximately the same low toxicity of the tested SAMPs with a linear type of amphipathicity, it is recommended to use those that contain the cationic arginine or histidine residues to create antibacterial or antifungal peptide agents, respectively.
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