Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new user$CP$ Invariance Study of $J/psitoLambdabarLambda$ and $Lambda$ Nonpleptonic Decays in Helicity Frame
92
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We present the joint helicity amplitudes for $J/psi to Lambda bar{Lambda}$, $Lambda(barLambda)$ decays to different final states in the helicity frame. Two observables to search for $CP$ violation in $J/psitoLambdabarLambda$ can be expressed with the information of helicity angles of baryon and antibaryon. Four decay parameters of $Lambda$ and $barLambda$, namely, $alpha_-,alpha_+,alpha_0$ and $baralpha_0$, can be obtained with the joint helicity amplitude equations by the likelihood fit method. With the data sample of $10^{10}$ $J/psi$ decays accumulated by BESIII, the precision of the measurements is estimated to be about $10^{-3}$.
rate research
Read More
It is shown that interference of the amplitudes for the decays $Lambda_b to Lambda D$ and $Lambda_b to Lambda bar{D}^0$ gives rise to CP-violation.
CP invariance condition and rephasing invariance in KM scheme of CP violation is discussed. The CP violation measures in B physics, corresponding to the three angles of unitarity triangle are given in rephasing invariant form. With the obtained results it is shown that the sum of the three CP angles to be measured at B factories becomes $pi$ even if the Kobayashi-Maskwa matrix is not a $3times 3$ unitary matrix under reasonable assumptions.
We have compared the proton and antiproton angular distributions in 117 million Xi-minus -> Lambda + pi-minus -> proton + pi-minus + pi-minus and 41 million anti-Xi-minus -> anti-Lamba + pi-plus -> antiproton + pi-plus + pi-plus decays using a subset of the data from the HyperCP experiment (E871) at Fermilab. We find no evidence of CP violation, with the direct-CP-violating parameter $A_{XiLambda} = frac{alpha_{Xi}alpha_{Lambda} - bar{alpha}_{Xi}bar{alpha}_{Lambda}}{alpha_{Xi}alpha_{Lambda} + bar{alpha}_{Xi}bar{alpha}_{Lambda}} = [0.0+/-5.1(stat)+/-4.4(syst)]{times}10^{-4}$.
In this paper, we calculate the $B_cto J/psi$ helicity form factors (HFFs) up to twist-4 accuracy by using the light-cone sum rules approach. After extrapolating those HFFs to the physically allowable $q^2$ region, we investigate the $B^+_c$-meson two-body decays and semi-leptonic decays $B_c^+ to J/psi+(P, V, ell^+ u_ell)$, where $P$ and $V$ stand for a light pseudo-scalar meson and a vector meson, respectively. The branching fractions can be derived by using the CKM matrix element and the $B_c$ lifetime from the Particle Data Group, and we obtain ${cal B}(B_c^+ to J/psi pi^+)=(0.132^{+0.002}_{-0.002})%$, ${cal B}(B_c^+ to J/psi K^+)=(0.010^{+0.000}_{-0.000})%$, ${cal B}(B_c^+ to J/psi rho^+) =(0.755^{+0.030}_{-0.034})%$, ${cal B}(B_c^+ to J/psi K^{ast +})=(0.043^{+0.001}_{-0.001})%$, ${cal B}(B_c^+ to J/psi mu^+ u_mu)=(2.808^{+0.547}_{-0.704})%$ and ${cal B}(B_c^+ to J/psi tau^+ u_tau)=(0.563^{+0.137}_{-0.178})%$. We then obtain ${cal R}_{pi^+/mu^+ u_mu} = 0.047^{+ 0.009}_{-0.012}$ and ${cal R}_{K^+ / pi^+} = 0.075^{+0.005}_{-0.005}$, which agree with the LHCb measured value within $1sigma$-error. We also obtain ${cal R}_{J/psi}=0.200^{+ 0.062}_{-0.081}$, which like other theoretical predictions, are consistent with the LHCb measured value within $2sigma$-error.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
