SND Upgade Abramov, G. N; Achasov, M. N; Aulchenko, V. M ...
05/2001
Journal Article
Odprti dostop
eConf C010430:T10,2001 The program of upgrade of the Spherical Neutral Detector for future
experiments at a new VEPP-2000 $e^+e^-$ collider is presented. Modernization
includes upgrades of ...electromagnetic calorimeter, tracking system, detector
electronics, data acquisition system, and offline software. It is also planned
to equip the detector with two new subsystems: particle identification system
based on aerogel Cherenkov counters and external electron tagging system for
$\gamma\gamma$ physics.
Using data collected in the Belle experiment at the KEKB asymmetric-energy
$e^+e^-$ collider we search for transitions $\Upsilon(4S) \rightarrow
\eta_b(1S)\omega$, $\Upsilon(5S) \rightarrow ...\eta_b(1S)\omega$ and
$\Upsilon(5S) \rightarrow \eta_b(2S)\omega$. No significant signals are
observed and we set 90\% confidence level upper limits on the corresponding
visible cross sections: $0.2 ~\textrm{pb}, 0.4 ~\textrm{pb}$ and $1.9
~\textrm{pb}$, respectively.
We report observations of the Cabibbo suppressed decays B{yields}D{sup (*)}K{sup -} using a 10.4 fb{sup -1} data sample accumulated at the {Upsilon}(4S) resonance with the Belle detector at the KEKB ...e{sup +}e{sup -} storage ring. We find that the ratios of Cabibbo suppressed to Cabibbo favored branching fractions are B(B{sup -}{yields}D{sup 0}K{sup -})/B(B{sup -} {yields}D{sup 0}{pi}{sup -})= 0.079{+-} 0.009{+-} 0.006 , B({bar B}{sup 0} {yields}D{sup +}K{sup -})/B({bar B}{sup 0 }{yields} D{sup +}{pi}{sup -}) =0.068 {+-}0.015 {+-}0.007 , B(B{sup -}{yields} D{sup *0}K{sup -}) /B(B{sup -} {yields}D{sup *0}{pi}{sup -})= 0.078{+-} 0.019{+-} 0.009 , and B({bar B}{sup 0}{yields} D{sup *+}K{sup -})/ B({bar B}{sup 0}{yields} D{sup *+}{pi}{sup -})=0.074{+-}0.015{+-} 0.006 . These are the first observations of the B{yields}D{sup +}K{sup -} , D{sup *0}K{sup -} , and D{sup *+}K{sup -} decay processes.
We report measurements of the branching fractions for B{sup 0}{yields}{pi}{sup +}{pi}{sup -} , K{sup +}{pi}{sup -} , K{sup +}K{sup -} , and K{sup 0}{pi}{sup 0} and B{sup +}{yields}{pi}{sup +}{pi}{sup ...0} , K{sup +}{pi}{sup 0} , K{sup 0}{pi}{sup +} , and K{sup +}{bar K}{sup 0} , based on 10.4 fb{sup -1} of data collected on the {Upsilon}(4S) resonance with the Belle detector. We find B(B{sup 0}{yields}{pi}{sup +}{pi}{sup -})=(0.56{sup +0.23+0.04}{sub -0.20-0.0 5}) x 10{sup -5} , B(B{sup 0}{yields}K{sup +}{pi}{sup -})=(1.93{sup +0.34 +0.15}{sub -0.32-0.06}) x 10{sup -5} , B(B{sup +}{yields}K{sup +}{pi}{sup 0})=(1.63{sup +0.35+0.16}{sub -0.33-0.1 8}) x 10{sup -5} , B(B{sup +}{yields}K{sup 0}{pi}{sup +})=(1.37{sup +0.57+0.19}{sub -0.48-0.1 8}) x 10{sup -5} , and B(B{sup 0}{yields}K{sup 0}{pi}{sup 0})=(1.60{sup +0.72+0.25}{sub -0.59-0.2 7}) x 10{sup -5} . We also set upper limits on the branching fractions for B{sup +}{yields}{pi}{sup +}{pi}{sup 0} , B{sup 0}{yields}K{sup +}K{sup -} , and B{sup +}{yields}K{sup +}{bar K}{sup 0} .
The interaction of a periodic pulsed energy source with a closing shock wave that arises near an airfoil in transonic flight regimes has been studied. The evolution of the shock-wave structure near a ...symmetric airfoil is analyzed based on a numerical solution of two-dimensional nonstationary equations of gasdynamics. A resonance interaction mechanism is established that leads to a significant (by an order of magnitude) decrease in the wave drag of the airfoil.
PDF
