اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدFirst measurement of time-dependent CP violation in Bs -> K+K- decays
126
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
Direct and mixing-induced CP-violating asymmetries in Bs -> K+K- decays are measured for the first time using a data sample of pp collisions, corresponding to an integrated luminosity of 1.0 fb^{-1}, collected with the LHCb detector at a centre-of-mass energy of 7 TeV. The results are C_{KK} = 0.14 pm 0.11 pm 0.03 and S_{KK} = 0.30 pm 0.12 pm 0.04, where the first uncertainties are statistical and the second systematic. The corresponding quantities are also determined for B0 -> pi+pi- decays to be C_{pipi} = -0.38 pm 0.15 pm 0.02 and S_{pipi} = -0.71 pm 0.13 pm 0.02, in good agreement with existing measurements.
قيم البحث
اقرأ أيضاً
We report a measurement of time-dependent $CP$ violation in $B^0 to K^0_S pi^0 pi^0$ decays using a data sample of $772 times 10^6$ $Bbar{B}$ pairs collected by the Belle experiment runnin g at the $Upsilon (4S)$ resonance at the KEKB $e^+ e^-$ colli
der. This decay proceeds mainly via a $bto sdbar{d}$ penguin amplitude. The results are $sin 2phi^{rm eff}_1 = 0.92^{+0.27}_{-0.31}~$ (stat.) $pm 0.11$ (syst.) and $mathcal{A} = 0.28 pm 0.21$ (stat.) $pm 0.04$ (syst.), which are the most precise measurements of $CP$ violati on in this decay mode to date. The value for the $CP$-violating parameter $sin 2phi^{rm eff}_1$ is consistent with that obtained using decay modes proceeding via a $bto cbar{c}s$ tree amplitude.
We report a measurement of $CP$ violating asymmetries in $B^0(overline{B}^0) to K^+ K^- K^0_S$ decays with a time-dependent Dalitz approach. This analysis is based on a data sample of $657times 10^6$ $Boverline{B}$ pairs accumulated at the $Upsilon(4
S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. As the result of an unbinned maximum likelihood fit to the selected candidates, the mixing-induced and direct $CP$ violation parameters, $phi^{rm eff}_1$ and ${cal A}_{CP}$ are obtained for $B^0 to phi(1020) K^0_S$, $B^0 to f_0(980) K^0_S$ and other $B^0 to K^+ K^- K^0_S$ decays. We find four solutions that describe the data. There are {eqnarray*} phi_1^{rm eff}(B^0to phi(1020) K^0_S) & = & (32.2 pm 9.0 pm 2.6 pm 1.4)^{circ}; phi_1^{rm eff}(B^0to phi(1020) K^0_S) & = & (26.2 pm 8.8 pm 2.7 pm 1.2)^{circ}; phi_1^{rm eff}(B^0to phi(1020) K^0_S) & = & (27.3 pm 8.6 pm 2.8 pm 1.3)^{circ}; {rm and} phi_1^{rm eff}(B^0to phi(1020) K^0_S) & = & (24.3 pm 8.0 pm 2.9 pm 5.2)^{circ}.{eqnarray*} The values for the $CP$ violating phase in $B^0to phi(1020) K^0_S$ are similar but other properties of the Dalitz plot are quite different for the four solutions. These four solutions have consistent $phi^{rm eff}_1$ values for all three $B$ meson decay channels and none of them deviates significantly from the values measured in $B to (cbar{c}) K^0$ decays with the currently available statistics. In addition, we find no significant direct $CP$ violation.
The time-dependent $CP$ asymmetry in $B_s^0 to J/psi K^+K^-$ decays is measured using $pp$ collision data, corresponding to an integrated luminosity of $3.0$fb$^{-1}$, collected with the LHCb detector at centre-of-mass energies of $7$ and $8$TeV. In
a sample of 96 000 $B_s^0 to J/psi K^+K^-$ decays, the $CP$-violating phase $phi_s$ is measured, as well as the decay widths $Gamma_{L}$ and $Gamma_{H}$ of the light and heavy mass eigenstates of the $B_s^0-bar{B}_s^0$ system. The values obtained are $phi_s = -0.058 pm 0.049 pm 0.006$ rad, $Gamma_s equiv (Gamma_{L}+Gamma_{H})/2 = 0.6603 pm 0.0027 pm 0.0015$ps$^{-1}$, and$DeltaGamma_s equiv Gamma_{L} - Gamma_{H} = 0.0805 pm 0.0091 pm 0.0032$ps$^{-1}$, where the first uncertainty is statistical and the second systematic. These are the most precise single measurements of those quantities to date. A combined analysis with $B_s^{0} to J/psi pi^+pi^-$ decays gives $phi_s = -0.010 pm 0.039 $rad. All measurements are in agreement with the Standard Model predictions. For the first time the phase $phi_s$ is measured independently for each polarisation state of the $K^+K^- $ system and shows no evidence for polarisation dependence.
An analysis of B0->D K*0 decays is presented, where D represents an admixture of D0 and D0b mesons reconstructed in four separate final states: K-pi+, pi-K+, K+K- and pi+pi-. The data sample corresponds to 3.0fb-1 of proton-proton collision, collecte
d by the LHCb experiment. Measurements of several observables are performed, including CP asymmetries. The most precise determination is presented of rB(DK*0), the magnitude of the ratio of the amplitudes of the decay B0->D K+ pi- with a b->u or a b->c transition, in a K pi mass region of +/-50 MeV/c2 around the K*(892) mass and for an absolute value of the cosine of the K*0 helicity angle larger than 0.4.
Using pp collision data, corresponding to an integrated luminosity of $1.0 mathrm{fb}^{-1}$, collected by LHCb in 2011 at a center-of-mass energy of 7 TeV, we report the measurement of direct CP violation in $B^0_s to K^-pi^+$ decays, $A_{C/!P}(B^0_s
rightarrow K^- pi^+)=0.27 pm 0.04,mathrm{(stat)} pm 0.01,mathrm{(syst)}$, with significance exceeding five standard deviations. This is the first observation of CP violation in the decays of $B^0_s$ mesons. Furthermore, we provide an improved determination of direct CP violation in $B^0 to K^+pi^-$ decays, $A_{C/!P}(B^0rightarrow K^+ pi^-)=-0.080 pm 0.007,mathrm{(stat)} pm 0.003,mathrm{(syst)}$, which is the most precise measurement of this quantity to date.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
