اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدEvidence for the charmless annihilation decay mode $B^0_s to pi^+pi^-$
137
0
0.0
(
0
)
تأليف
CDF Collaboration
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We search for annihilation decay modes of neutral $b$ mesons into pairs of charmless charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using a data sample corresponding to 6 fb$^{-1}$ of integrated luminosity, we obtain the first evidence for the $B^0_s to pi^+pi^-$ decay, with a significance of $3.7sigma$, and a measured branching ratio $mathcal{B}(B^0_s to pi^+pi^-)= (0.57 pm 0.15 (stat) pm 0.10 (syst))times 10^{-6}$. A search for the $B^0 to K^+K^-$ mode in the same sample yields a significance of $2.0sigma$, and a central value estimate $mathcal{B}(B^0 to K^+K^-)= (0.23 pm 0.10 (stat) pm 0.10 (syst))times 10^{-6}$.
قيم البحث
اقرأ أيضاً
The first observation of the rare decay$B^0_s to phipi^+pi^-$ and evidence for $B^0 to phipi^+pi^-$ are reported, using $pp$ collision data recorded by the LHCb detector at centre-of-mass energies $sqrt{s} = 7$ and 8~TeV, corresponding to an integrat
ed luminosity of $3{mbox{,fb}^{-1}}$. The branching fractions in the $pi^+pi^-$ invariant mass range $400<m(pi^+pi^-)<1600{mathrm{,Mekern -0.1em V!/}c^2}$ are $[3.48pm 0.23pm 0.17pm 0.35]times 10^{-6}$ and $[1.82pm 0.25pm 0.41pm 0.14]times 10^{-7}$ for $B^0_s to phipi^+pi^-$ and $B^0 to phipi^+pi^-$ respectively, where the uncertainties are statistical, systematic and from the normalisation mode $B^0_s to phiphi $. A combined analysis of the $pi^+pi^-$ mass spectrum and the decay angles of the final-state particles identifies the exclusive decays $B^0_s to phi f_0(980) $, $B_s^0 to phi f_2(1270) $, and $B^0_s to phirho^0$ with branching fractions of $[1.12pm 0.16^{+0.09}_{-0.08}pm 0.11]times 10^{-6}$, $[0.61pm 0.13^{+0.12}_{-0.05}pm 0.06]times 10^{-6}$ and $[2.7pm 0.7pm 0.2pm 0.2]times 10^{-7}$, respectively.
We report a study of the suppressed decay B^- -> DK^-, D -> K^+pi^-pi^0, where D denotes either a D^0 or a bar{D}^0 meson. The decay is sensitive to the CP-violating parameter phi_3. Using a data sample of 772 x 10^6 Bbar{B} pairs collected at the Up
silon(4S) resonance with the Belle detector, we measure the ratio of branching fractions of the above suppressed decay to the favored decay B^- -> DK^-, D -> K^-pi^+pi^0. Our result is R_{DK} = [1.98 +/- 0.62(stat.) +/- 0.24(syst.)] x 10^{-2}, which indicates the first evidence of the signal for this suppressed decay with a significance of 3.2 standard deviations. We measure the direct CP asymmetry between the suppressed B^- and B^+ decays to be A_{DK} = 0.41 +/- 0.30 (stat.) +/- 0.05 (syst.). We also report measurements for the analogous quantities R_{Dpi} and A_{Dpi} for the decay B^- -> Dpi^-, D -> K^+pi^-pi^0.
Evidence for the hadronic annihilation decay mode $B^{+} to D_s^{+}phi$ is found with greater than $3sigma$ significance. The branching fraction and CP asymmetry are measured to be mathcal{B}(B^{+} to D_s^{+}phi) &=& (1.87^{+1.25}_{-0.73}({rm stat})
pm 0.19 ({rm syst}) pm 0.32 ({rm norm})) times 10^{-6}, mathcal{A}_{CP}(B^{+} to D_s^{+}phi) &=& -0.01 pm 0.41 ({rm stat}) pm 0.03 ({rm syst}). The last uncertainty on $mathcal{B}(B^{+} to D_s^{+}phi)$ is from the branching fractions of the $B^+ to D_s^+ kern 0.2embar{kern -0.2em D}{}^0$ normalization mode and intermediate resonance decays. Upper limits are also set for the branching fractions of the related decay modes $B^{+}_{(c)} to D^{+}_{(s)} K^{*0}$, $B^{+}_{(c)} to D^{+}_{(s)} kern 0.2embar{kern -0.2em K}{}^{*0}$ and ${B_c^{+} to D^{+}_{s}phi}$, including the result ${mathcal{B}(B^+ to D^+ K^{*0})} < 1.8 times 10^{-6}$ at the 90% credibility level.
We present the results of a Dalitz plot analysis of D^0 to K^0_S pi^0 pi^0 using the CLEO-c data set of 818 inverse pico-barns of e^+ e^- collisions accumulated at sqrt{s} = 3.77 GeV. This corresponds to three million D^0 D^0-bar pairs from which we
select 1,259 tagged candidates with a background of 7.5 +- 0.9 percent. Several models have been explored, all of which include the K^*(892), K^*_2(1430), K^*(1680), the f_0(980), and the sigma(500). We find that the combined pi^0 pi^0 S-wave contribution to our preferred fit is (28.9 +- 6.3 +- 3.1)% of the total decay rate while D^0 to K^*(892)^0 pi^0 contributes (65.6 +- 5.3 +- 2.5)%. Using three tag modes and correcting for quantum correlations we measure the D^0 to K^0_S pi^0 pi^0 branching fraction to be (1.059 +- 0.038 +- 0.061)%.
The suppressed decay chain B- -> DK-, D -> K+pi-, where D indicates a anti-D0 or D0 state, provides important information on the CP-violating angle phi_3. We measure the ratio R_{DK} of the decay rates to the favored mode B- -> DK-, D -> K-pi+ to be
R_{DK} = [1.63^{+0.44}_{-0.41}(stat)^{+0.07}_{-0.13}(syst)] x 10^{-2}, which indicates the first evidence of the signal with a significance of 4.1sigma. We also measure the asymmetry A_{DK} between the charge-conjugate decays to be A_{DK} = -0.39^{+0.26}_{-0.28}(stat)^{+0.04}_{-0.03}(syst). The results are based on the full 772 x 10^6 B anti-B pair data sample collected at the Upsilon(4S) resonance with the Belle detector.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
