اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدMeasurement of the CP-violating phase $phi_s$ in $overline{B}^0_srightarrow J/psi pi^+pi^-$ decays
72
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
The mixing-induced CP-violating phase $phi_s$ in ${B}^0_s$ and $overline{B}^0_s$ decays is measured using the $J/psi pi^+pi^-$ final state in data, taken from 3,fb$^{-1}$ of integrated luminosity, collected with the LHCb detector in 7 and 8 TeV centre-of-mass $pp$ collisions at the LHC. A time-dependent flavour-tagged amplitude analysis, allowing for direct CP violation, yields a value for the phase $phi_s=70pm 68pm 8$,mrad. This result is consistent with the Standard Model expectation and previous measurements.
قيم البحث
اقرأ أيضاً
The resonant structure of the reaction $overline{B}^0rightarrow J/psi pi^+pi^-$ is studied using data from 3 fb$^{-1}$ of integrated luminosity collected by the LHCb experiment, one-third at 7 Tev center-of-mass energy and the remainder at 8 Tev. The
invariant mass of the $pi^+pi^-$ pair and three decay angular distributions are used to determine the fractions of the resonant and non-resonant components. Six interfering $pi^+pi^-$ states: $rho(770)$, $f_0(500)$, $f_2(1270)$, $rho(1450)$, $omega(782)$ and $rho(1700)$ are required to give a good description of invariant mass spectra and decay angular distributions. The positive and negative CP fractions of each of the resonant final states are determined. The $f_0(980)$ meson is not seen and the upper limit on its presence, compared with the observed $f_0(500)$ rate, is inconsistent with a model of tetraquark substructure for these scalar mesons at the eight standard deviation level. In the $qoverline{q}$ model, the absolute value of the mixing angle between the $f_0(980)$ and the $f_0(500)$ scalar mesons is limited to be less than $17^{circ}$ at 90% confidence level.
The resonant structure of the decay $overline{B}_s^0to J/psipi^+pi^-$ is studied using data corresponding to 3 fb$^{-1}$ of integrated luminosity from $pp$ collisions by the LHC and collected by the LHCb detector. Five interfering $pi^+pi^-$ states a
re required to describe the decay: $f_0(980),f_0(1500),f_0(1790),f_2(1270)$, and $f_2^{prime}(1525)$. An alternative model including these states and a non-resonant $J/psi pi^+pi^-$ component also provides a good description of the data. Based on the different transversity components measured for the spin-2 intermediate states, the final state is found to be compatible with being entirely $CP$-odd. The $CP$-even part is found to be $<2.3$% at 95% confidence level. The $f_0(500)$ state is not observed, allowing a limit to be set on the absolute value of the mixing angle with the $f_0(980)$ of $<7.7^{circ}$ at 90% confidence level, consistent with a tetraquark interpretation of the $f_0(980)$ substructure.
Time-dependent CP violation is measured in the $B^0rightarrow J/psipi^+pi^-$ channel for each $pi^+pi^-$ resonant final state using data collected with an integrated luminosity of 3.0 fb$^{-1}$ in $pp$ collisions using the LHCb detector. The final st
ate with the largest rate, $J/psirho^0(770)$, is used to measure the CP-violating angle $2beta^{rm eff}$ to be $(41.7pm 9.6_{-6.3}^{+2.8})^{circ}$. This result can be used to limit the size of penguin amplitude contributions to CP violation measurements in, for example, $B_s^0rightarrow J/psiphi$ decays. Assuming approximate SU(3) flavour symmetry and neglecting higher order diagrams, the shift in the CP-violating phase $phi_s$ is limited to be within the interval [$-1.05^circ$, +$1.18^circ$] at 95% confidence level. Changes to the limit due to SU(3) symmetry breaking effects are also discussed.
A flavour-tagged decay-time-dependent amplitude analysis of $B_s^0to(K^+pi^-)(K^-pi^+)$ decays is presented in the $K^{pm}pi^{mp}$ mass range from 750 to 1600 MeV$/c^2$. The analysis uses $pp$ collision data collected with the LHCb detector at centre
-of-mass energies of $7$ and $8$ TeV, corresponding to an integrated luminosity of $3.0$ fb$^{-1}$. Several quasi-two-body decay modes are considered, corresponding to $K^{pm}pi^{mp}$ combinations with spin 0, 1 and 2, which are dominated by the $K_0^*(800)^0$ and $K_0^*(1430)^0$, the $K^*(892)^0$ and the $K_2^*(1430)^0$ resonances, respectively. The longitudinal polarisation fraction for the $B_s^0to K^*(892)^0overline{K}^*(892)^0$ decay is measured as $f_L=0.208 pm 0.032 pm 0.046$, where the first uncertainty is statistical and the second is systematic. The first measurement of the mixing-induced $CP$-violating phase, $phi_s^{doverline{d}}$, in $bto doverline{d}s$ transitions is performed, yielding a value of $phi_s^{doverline{d}}=-0.10$ $pm$ $0.13$ (stat) $pm$ $0.14$ (syst) rad.
Measurement of the mixing-induced CP-violating phase phi_s in Bs decays is of prime importance in probing new physics. Here 7421 +/- 105 signal events from the dominantly CP-odd final state J/psi pi+ pi- are selected in 1/fb of pp collision data coll
ected at sqrt{s} = 7 TeV with the LHCb detector. A time-dependent fit to the data yields a value of phi_s=-0.019^{+0.173+0.004}_{-0.174-0.003} rad, consistent with the Standard Model expectation. No evidence of direct CP violation is found.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
