ترغب بنشر مسار تعليمي؟ اضغط هنا

New results on e+e- -> hadrons exclusive cross sections from experiments with SND detector at VEPP-2M e+e- collider in the energy range sqrt(s)=0.4-1.4 GeV

65   0   0.0 ( 0 )
 نشر من قبل Sergey Serednyakov I
 تاريخ النشر 2005
  مجال البحث
والبحث باللغة English




اسأل ChatGPT حول البحث

New results of the e+e- -> pi+pi-, K+K-, K_SK_L, pi0/gamma, eta0/gamma processes cross section measurements are presented. The results are based on the 30 pb^-1 data, accumulated by SND detector at VEPP-2M e+e- collider in the energy range sqrt(s)=0.4-1.4 GeV during 1995-2000 years. The comparison with existing experimental data shows that the measurement accuracy is close to or better than the world average. For the e+e- -> pi+pi- process the accuracy is about 0.01. This is important for calculation of hadronic contribution into the muon anomalous magnetic moment.



قيم البحث

اقرأ أيضاً

In experiment with the SND detector at VEPP-2M $e^+e^-$ collider the $e^+e^-toetagamma$ cross section was measured in the energy range $E$=0.60--1.38 GeV with the integrated luminosity of 27.8 pb$^{-1}$. The measured cross section is well described b y the vector meson dominance model with contributions from the $rho(770)$, $omega(783)$, $phi(1020)$, $rho^{prime}(1465)$ resonances and agrees with results of previous measurements. The decay probabilities $BR(phitoetagamma)$, $BR(omegatoetagamma)$ and $BR(rhotoetagamma)$ were measured with the accuracies better than or comparable to the world averages.
The cross section of the process $e^+e^- to K^+K^-$ was measured in the energy range $sqrt{s}$ = 1.04--1.38 GeV in the SND experiment at the VEPP-2M $e^+e^-$ collider. The measured cross section is described by the model of vector meson dominance wit h contributions from the light vector mesons $rho$, $omega$, $phi$ and their lowest excitations. The mean statistical accuracy of the measurement is 4.4 %, and the systematic uncertainty is 5.2 %.
Results of the SND experiment at the VEPP-2M e+ e- collider on the QED processes e+ e- --> e+ e- gamma and e+ e- --> e+ e- gamma gamma with production at large angles are presented. Energy and angular distributions of the final particles were studied . No deviations from QED with an accuracy of 3.8% for the first process and 10.3% for the second were found.
The process $e^+e^- to pi^0gamma$ has been studied in the experiment with the SND detector at the VEPP-2M $e^+e^-$ collider. The $e^+e^- to pi^0gamma$ cross section has been measured in the center-of-mass energy range from 0.60 to 1.38 GeV. The cross section is well described by the vector meson dominance model. From the fit to the cross section data we have determined the branching fractions $B(rhotopi^0gamma)=(4.20pm0.52)times10^{-4}$, $B(omegatopi^0gamma)=(8.88pm0.18)%$, $B(phitopi^0gamma)=(1.367pm0.072)times10^{-3}$, and the relative phase between the $rho$ and $omega$ amplitudes $varphi_{rho}=(-12.7pm4.5)^circ$. Our data on the process $e^+e^- to pi^0gamma$ are the most accurate to date.
The cross section of the process $e^+ e^-topi^+pi^-$ has been measured in the Spherical Neutral Detector (SND) experiment at the VEPP-2000 $e^+e^-$ collider VEPP-2000 in the energy region $525 <sqrt[]{s} <883$ MeV. The measurement is based on data wi th an integrated luminosity of about 4.6 pb$^{-1}$. The systematic uncertainty of the cross section determination is 0.8 % at $sqrt{s}>0.600$ GeV. The $rho$ meson parameters are obtained as $m_rho = 775.3pm 0.5pm 0.6$ MeV, $Gamma_rho = 145.6pm 0.6pm 0.8$ MeV, $B_{rhoto e^+ e^-}times B_{rhotopi^+pi^-} = (4.89pm 0.02pm 0.04)times 10^{-5}$, and the parameters of the $e^+ e^-toomegatopi^+pi^-$ process, suppressed by $G$-parity, as $B_{omegato e^+ e^-}times B_{omegatopi^+pi^-}= (1.32pm 0.06pm 0.02)times 10^{-6} $ and $phi_{rhoomega} = 110.7pm 1.5pm1.0$ degrees.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا