In the experiment with the SND detector at the VEPP-2000
collider, events of the process
were separated via measuring, in each counter of the multichannel calorimeter based on 1640 NaI(Tl) crystals, ...the time of delay of the signal from nonrelativistic antineutrons. The time resolution for events of the process
was 0.8 ns. The measured time spectrum of delays of the signal from antineutrons in the calorimeter at the c.m. energy of 1902 MeV agrees with the results of calculations.
The process
was studied in the energy range between 1 and 2 GeV to the best precision in the world. The data used correspond to an integrated luminosity of
accumulated with the SND detector at the ...VEPP-2000
collider. The statistical accuracy of the measured cross section is 2 to 22
, whereas the systematic uncertainty is 2.6 to 14
. The present results agree with the results of earlier measurements but have a better precision.
A number of new octahydro-2
H
-chromene acetamide derivatives based on the monoterpenoid (−)-isopulegol were synthesized using a one-pot three-component Prins—Ritter reaction. The structure of the ...target compounds was determined using
1
H and
13
C NMR spectroscopy, high resolution mass spectrometry, and X-ray diffraction analysis. Most of the products exhibited high analgesic activity in
in vivo
tests. The highest analgesic activity was found for spirocyclic compound (4
S
)-
2d
, the effect of which is apparently mediated through the dopamine system. It was shown that compound (4
S
)-
2d
has a low acute toxicity.
We present the results of the first Dalitz plot analysis of the decay D 0 → K-π +η. The analysis is performed on a data set corresponding to an integrated luminosity of 953 fb-1 collected by the ...Belle detector at the asymmetric-energy e+e- KEKB collider. The Dalitz plot is well described by a combination of the six resonant decay channels K- * (892)0 η, K-a0(980)+, K-a2(1320)+, K¯ * (1410)0 η, K* (1680)-π + and K* 2 (1980)-π +, together with Kπ and Kη S-wave components. The decays K* (1680)- → K-η and K* 2 (1980)- → K-η are observed for the first time. We measure ratio of the branching fractions, B(D0→K-π+η) B(D0→K=π+) = 0.500 ± 0.002(stat) ± 0.020(syst) ± 0.003(BPDG). Using the Dalitz fit result, the ratio B(K*(1680)→Kη) B(K*(1680)→Kπ) is measured to be 0.11±0.02(stat)+0.06 =0.04(syst)± 0.04(BPDG); this is much lower than the theoretical expectations (≈ 1) made under the assumption that K* (1680) is a pure 1 3D1 state. The product branching fraction B(D 0 → K* 2 (1980)- → K-ηπ +) = (2.2 +1.7 -1.9 ) × 10-4 is determined. In addition, the πη' contribution to the a0(980)± resonance shape is confirmed with 10.1σ statistical significance using the three-channel Flatté model. We also measure B(D 0 → K¯ * (892)0 η) = (1.41+0.13 -0.12)%. This is consistent with, and more precise than, the current world average (1.02 ± 0.30)%, deviates with a significance of more than 3σ from the theoretical predictions of (0.51-0.92)%.
Using the SND detector, the process
was studied in the energy range between 1.05 and 2.00 GeV. The respective measurement was performed on the basis of data accumulated in the experiments at the ...VEPP-2000 electron–positron collider throughout the runs of 2011 and 2012. Also, the invariant-mass spectra of the
and
combinations were analyzed in the energy range between 1.15 and 2 GeV. This resulted in finding an indication that the
excited state decayed predominantly through the
intermediate state.
Parkinson’s disease (PD) is a progressive neurodegenerative disorder mainly characterized by movement dysfunction. Earlier, it was found that ...(1R,2R,6S)-3-methyl-6-(prop-1-en-2-yl)cyclohex-3-ene-1,2-diol (Prottremin) demonstrated antiparkinsonian activity in vivo on different animal models of PD. The paper presents synthesis of new Prottremin derivative, (1R,2R,6S)-2(4-(4-isopropylbenzyl)piperazin-1-yl)-3-methyl-6-(prop-1-en-2-yl)cyclohex-3-enol. The derivative was obtained by epoxide ring opening reaction with 1-(4-isopropylbenzyl)piperazine. The product yield was 48% after purification.
We perform a full amplitude analysis of the process e+e−→J/ψDD¯, where D refers to either D0 or D+. A new charmoniumlike state X*(3860) that decays to DD¯ is observed with a significance of 6.5σ. Its ...mass is (3862−32+26 −13+40) MeV/c2, and its width is (201−67+154 −82+88) MeV. The JPC=0++ hypothesis is favored over the 2++ hypothesis at the level of 2.5σ. The analysis is based on the 980 fb−1 data sample collected by the Belle detector at the asymmetric-energy e+e− collider KEKB.
The present work continues a series of the KEDR measurements of the R value that started in 2010 at the VEPP-4M e+e− collider. By combining new data with our previous results in this energy range we ...measured the values of Ruds and R at nine center-of-mass energies between 3.08 and 3.72 GeV. The total accuracy is about or better than 2.6% at most of energy points with a systematic uncertainty of about 1.9%. Together with the previous precise R measurement at KEDR in the energy range 1.84–3.05 GeV, it constitutes the most detailed high-precision R measurement near the charmonium production threshold.
A range of heterogeneous ‐SO3H functionalized catalysts including carbon and halloysite nanotubes, commercial K10 clay, Amberlyst‐15 etc. was investigated for the first time using as a model the ...Prins‐Ritter reaction of (−)‐isopulegol with benzaldehyde and acetonitrile producing 4‐amido derivatives of octahydro‐2H‐chromenes (as (S)‐ and (R)‐diastereomers). A strong effect of water addition prior the reaction on the overall selectivity and the ratio of isomers in the case of heterogeneous and homogeneous (p‐toluenesulfonic acid) catalysis was found for the first time. The yield of the (R)‐diastereomer sharply increased with increasing amount of added water, while the S‐isomer prevailed with a minimum amount of added water. Experimental results and DFT calculations clearly indicate a kinetic control for R‐amide formation. Typically synthesis of 4‐amidooctahydro‐2H‐chromenes requires subzero temperatures and toxic catalysts, which were avoided in the current work. Nevertheless, the yield of the desired products (up to 83 %) at 30 °C after water addition exceeded the values reported previously. Thus, adding water is a simple and a very effective method for controlling both the yield and stereoselectivity of the Prins‐Ritter reaction products under mild conditions.
Just add water! A range of heterogeneous ‐SO3H functionalized catalysts were investigated for the first time using the Prins‐Ritter (−)‐isopulegol reaction with benzaldehyde and acetonitrile as a model producing 4‐amido derivatives of octahydro‐2H‐chromenes (as S‐ and R‐diastereomers). A strong effect of water addition prior the reaction on the overall selectivity and the ratio of isomers was found.
Here, we present a measurement of angular observables and a test of lepton flavor universality in the B → K*ℓ+ℓ- decay, where ℓ is either e or μ . The analysis is performed on a data sample ...corresponding to an integrated luminosity of 711fb-1 containing 772×106 B B ¯ pairs, collected at the Υ ( 4S ) resonance with the Belle detector at the asymmetric-energy e+e- collider KEKB. The finding is consistent with standard model (SM) expectations, where the largest discrepancy from a SM prediction is observed in the muon modes with a local significance of 2.6σ .
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