اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدSearch for the $Lambda_b rightarrow Lambda eta^prime$ and $Lambda_b rightarrow Lambda eta$ decays with the LHCb detector
214
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
A search is performed for the as yet unobserved baryonic $Lambda_b rightarrow Lambda eta^prime$ and $Lambda_b rightarrow Lambda eta$ decays with 3$fb^{-1}$ of proton-proton collision data recorded by the LHCb experiment. The $B^0 rightarrow K_S^0 eta^prime$ decay is used as a normalisation channel. No significant signal is observed for the $Lambda_b rightarrow Lambda eta^prime$ decay. An upper limit is found on the branching fraction of $mathcal{B}(Lambda_b rightarrow Lambda eta^prime)<3.1times10^{-6}$} at 90% confidence level. Evidence is seen for the presence of the $Lambda_b rightarrow Lambda eta$ decay at the level of $3sigma$ significance, with a branching fraction $mathcal{B}(Lambda_b rightarrow Lambda eta)=(9.3^{+7.3}_{-5.3})times10^{-6}$}.
قيم البحث
اقرأ أيضاً
We report the results of the first search for the decay $B_s^0 rightarrow eta^prime eta$ using $121.4~textrm{fb}^{-1}$ of data collected at the $Upsilon(5S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. We observ
e no significant signal and set a 90% confidence-level upper limit of %$7.1 times 10^{-5}$ $6.5 times 10^{-5}$ on the branching fraction of this decay.
In the Standard Model (SM) charmless hadronic decays $B_s^0 rightarrow eta^prime eta$ proceed via tree-level $bto u$ and penguin $bto s$ transitions. Penguin transitions are sensitive to Beyond-the-Standard-Model (BSM) physics scenarios and could aff
ect the branching fractions and {it CP} asymmetries in such decays. Once branching fractions for two-body decays $B_s to etaeta, etaeta^{prime}, eta^{prime}eta^{prime} $ are measured, and the theoretical uncertainties are reduced, it would be possible to extract {it CP} violating parameters from the data using the formalism based on SU(3)/U(3) symmetry. To achieve this goal, at least four of these six branching fractions need to be measured. Only the branching fraction for $B_s^0 to eta^{prime}eta^{prime}$ has been measured so far.
We study the hadronic decays of $Lambda_{c}^{+}$ to the final states $Sigma^{+}eta$ and $Sigma^+eta^prime$, using an $e^{+}e^{-}$ annihilation data sample of 567 pb$^{-1}$ taken at a center-of-mass energy of 4.6 GeV with the BESIII detector at the BE
PCII collider. We find evidence for the decays $Lambda_{c}^{+}rightarrowSigma^{+}eta$ and $Sigma^+eta^prime$ with statistical significance of $2.5sigma$ and $3.2sigma$, respectively. Normalizing to the reference decays $Lambda_c^+toSigma^+pi^0$ and $Sigma^+omega$, we obtain the ratios of the branching fractions $frac{{mathcal B}(Lambda_c^+toSigma^+eta)}{{mathcal B}(Lambda_c^+toSigma^+pi^0)}$ and $frac{{mathcal B}(Lambda_c^+toSigma^+eta^prime)}{{mathcal B}(Lambda_c^+toSigma^+omega)}$ to be $0.35 pm 0.16 pm 0.03$ and $0.86 pm 0.34 pm 0.07$, respectively. The upper limits at the 90% confidence level are set to be $frac{{mathcal B}(Lambda_c^+toSigma^+eta)}{{mathcal B}(Lambda_c^+toSigma^+pi^0)}<0.58$ and $frac{{mathcal B}(Lambda_c^+toSigma^+eta^prime)}{{mathcal B}(Lambda_c^+toSigma^+omega)}<1.2$. Using BESIII measurements of the branching fractions of the reference decays, we determine $mathcal B({Lambda_{c}^{+}rightarrowSigma^{+}eta})=(0.41pm0.19pm0.05)%$ ($<0.68%$) and $mathcal B({Lambda_{c}^{+}rightarrowSigma^{+}eta})=(1.34pm0.53pm0.21)%$ ($<1.9%$). Here, the first uncertainties are statistical and the second systematic. The obtained branching fraction of $Lambda_c^+toSigma^+eta$ is consistent with the previous measurement, and the branching fraction of $Lambda_{c}^{+}rightarrowSigma^{+}eta^{prime}$ is measured for the first time.
Based on a sample of $1.31 times 10^9$ $J/psi$ events collected with the BESIII detector, an amplitude analysis of the isospin-violating decays $eta^prime rightarrow pi^+pi^-pi^0$ and $eta^prime rightarrow pi^0pi^0pi^0$ is performed. A significant $P
$-wave contribution from $eta^prime rightarrow rho^{pm} pi^{mp}$ is observed for the first time in $eta^prime rightarrow pi^+pi^-pi^0$. The branching fraction is determined to be ${mathcal B}(eta^prime rightarrow rho^{pm}pi^{mp})=(7.44pm0.60pm1.26pm1.84)times 10^{-4}$, where the first uncertainty is statistical, the second systematic, and the third model dependent. In addition to the nonresonant $S$-wave component, there is a significant $sigma$ meson component. The branching fractions of the combined $S$-wave components are determined to be ${mathcal B}(eta^prime rightarrow pi^+pi^-pi^0)_S=(37.63pm0.77pm2.22pm4.48)times 10^{-4}$ and ${mathcal B}(eta^prime rightarrow pi^0pi^0pi^0)=(35.22pm0.82pm2.54)times 10^{-4}$, respectively. The latter one is consistent with previous BESIII measurements.
A search for $CP$ violation in $D^{pm}rightarrow eta^{prime} pi^{pm}$ and $D^{pm}_{s}rightarrow eta^{prime} pi^{pm}$ decays is performed using proton-proton collision data, corresponding to an integrated luminosity of $3$ fb$^{-1}$, recorded by the L
HCb experiment at centre-of-mass energies of $7$ and $8$ TeV. The measured $CP$-violating charge asymmetries are $A_{CP}(D^{pm} rightarrow eta^{prime} pi^{pm})=(-0.61pm 0.72 pm 0.53 pm 0.12)%$ and $A_{CP}(D^{pm}_{s}rightarrow eta^{prime} pi^{pm})=(-0.82pm 0.36 pm 0.22 pm 0.27)%$, where the first uncertainties are statistical, the second systematic, and the third are the uncertainties on the $A_{CP}(D^{pm} rightarrow K^0_S pi^{pm})$ and $A_{CP}(D^{pm}_{s}rightarrow phi pi^{pm})$ measurements used for calibration. The results represent the most precise measurements of these asymmetries to date.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
