اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدMeasurement of the CP-violation Parameter sin2$phi_1$ with a New Tagging Method at the $Upsilon(5S)$ Resonance
131
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We report a measurement of the CP-violation parameter sin2$phi_1$ at the $Upsilon(5S)$ resonance using a new tagging method, called $B$-$pi$ tagging. In $Upsilon(5S)$ decays containing a neutral $B$ meson, a charged $B$, and a charged pion, the neutral $B$ is reconstructed in the $J/psi K_S^0$ CP-eigenstate decay channel. The initial flavor of the neutral $B$ meson at the moment of the $Upsilon(5S)$ decay is opposite to that of the charged $B$ and may thus be inferred from the charge of the pion without reconstructing the charged $B$. From the asymmetry between $B$-$pi^+$ and $B$-$pi^-$ tagged $J/psi K_S^0$ yields, we determine sin2$phi_1$ = 0.57 $pm$ 0.58(stat) $pm$ 0.06(syst). The results are based on 121 fb$^{-1}$ of data recorded by the Belle detector at the KEKB $e^+ e^-$ collider.
قيم البحث
اقرأ أيضاً
We describe a flavor tagging algorithm used in measurements of the CP violation parameter sin2phi_1 at the Belle experiment. Efficiencies and wrong tag fractions are evaluated using flavor-specific B meson decays into hadronic and semileptonic modes.
We achieve a total effective efficiency of $ 28.8 +- 0.6 %.
We present a precise measurement of the CP violation parameter sin2phi_1 and the direct CP violation parameter A_f using the final data sample of 772x10^6 Bbar B pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmet
ric-energy e+e- collider. One neutral B meson is reconstructed in a J/psi K0S, psi(2S) K0S, chi_c1 K0S or J/psi K0L CP-eigenstate and its flavor is identified from the decay products of the accompanying B meson. From the distribution of proper time intervals between the two B decays, we obtain the following CP violation parameters: sin2phi_1=0.667+-0.023(stat)+-0.012(syst) and A_f=0.006+-0.016(stat)+-0.012(syst).
A measurement of the charm-mixing parameter $y_{CP}$ using $D^0 to K^+ K^-$, $D^0 to pi^+ pi^-$, and $D^0 to K^- pi^+$ decays is reported. The $D^0$ mesons are required to originate from semimuonic decays of $B^-$ and $overline{B}^0$ mesons. These de
cays are partially reconstructed in a data set of proton-proton collisions at center-of-mass energies of 7 and 8 TeV collected with the LHCb experiment and corresponding to an integrated luminosity of 3 fb$^{-1}$. The $y_{CP}$ parameter is measured to be $(0.57 pm 0.13(rm{stat.}) pm 0.09(rm{syst.}))%$, in agreement with, and as precise as, the current world-average value.
We report a measurement of the branching fraction of B^+ -> tau^+ nu_tau decays using a data sample of 772 x 10^6 BBbar pairs, collected at the Y(4S) resonance with the Belle detector at the KEKB asymmetric-energy e^+e^- collider. We reconstruct the
accompanying B meson in a semileptonic decay and detect the recoiling B candidate in the decay channel B^+ -> tau^+ nu_tau. We obtain a branching fraction of BR(B^+ -> tau^+ nu_tau) = [1.25 +- 0.28 (stat.) +- 0.27 (syst.)] x 10^-4. This result is in good agreement with previous measurements and the expectation from the calculation based on the Standard Model.
The existence of CP-violation in the leptonic sector is one of the most important issues for modern science. Neutrino physics is a key to the solution of this problem. JUNO (under construction) is the near future of neutrino physics. However CP-viola
tion is not a priority for the current scientific program. We estimate the capability of $delta_{rm CP}$ measurement, assuming a combination of the JUNO detector and a superconductive cyclotron as the antineutrino source. This method of measuring CP-violation is an alternative to conventional beam experiments. A significance level of 3$sigma$ can be reached for 22% of the $delta_{rm CP}$ range. The accuracy of measurement lies between 8$^{rm o}$ and 22$^{rm o}$. It is shown that the dominant influence on the result is the uncertainty in the mixing angle $Theta_{23}$.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
