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Babar Collaboration announced two new excited charmed baryons $Xi_c(3055)^+$ and $Xi_c(3123)^+$. We study their strong decays assuming they are D-wave states. Some assignments are excluded by comparing our numerical results with the experimental values of the total widths of $Xi_c(3055)^+$ and $Xi_c(3123)^+$. We also suggest some possible decay modes, which will be helpful to determine the properties of $Xi_c(3055)^+$ and $Xi_c(3123)^+$.
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Using a data sample of 980 ${rm fb}^{-1}$ of $e^+e^-$ annihilation data taken with the Belle detector operating at the KEKB asymmetric-energy $e^+e^-$ collider, we report the results of a study of excited $Xi_c$ states that decay, via the emission of photons and/or charged pions, into $Xi_c^0$ or $Xi_c^+$ ground state charmed-strange baryons. We present new measurements of the masses of all members of the $Xi_c^{prime}$, $Xi_c(2645)$, $Xi_c(2790)$, $Xi_c(2815)$, and $Xi_c(2980)$ isodoublets, measurements of the intrinsic widths of those that decay strongly, and evidence of previously unknown transitions.
We report measurements of the lifetimes of the $Lambda_c^+$, $Xi_c^+$ and $Xi_c^0$ charm baryons using proton-proton collision data at center-of-mass energies of 7 and 8tev, corresponding to an integrated luminosity of 3.0 fb$^{-1}$, collected by the LHCb experiment. The charm baryons are reconstructed through the decays $Lambda_c^+to pK^-pi^+$, $Xi_c^+to pK^-pi^+$ and $Xi_c^0to pK^-K^-pi^+$, and originate from semimuonic decays of beauty baryons. The lifetimes are measured relative to that of the $D^+$ meson, and are determined to be begin{align*} tau_{Lambda_c^+} &= 203.5pm1.0pm1.3pm1.4~{rm fs}, ewline tau_{Xi_c^+} &= 456.8pm3.5pm2.9pm3.1~{rm fs}, ewline tau_{Xi_c^0} &= 154.5pm1.7pm1.6pm1.0~{rm fs}, end{align*} where the uncertainties are statistical, systematic, and due to the uncertainty in the $D^+$ lifetime. The measurements are approximately 3--4 times more precise than the current world average values. The $Lambda_c^+$ and $Xi_c^+$ lifetimes are in agreement with previous measurements; however, the $Xi_c^0$ baryon lifetime is approximately 3.3 standard deviations larger than the world average value.
Measurements on the weak decay asymmetry parameters of charmed baryon, say $Xi_c$, provide more information on the $W$-emission and $W$-exchange mechanisms controlled by the strong and weak interactions. Taking advantage of the spin polarization in the charmed baryon decays, we investigate the possibility to measure the weak decay asymmetry parameters in the $e^{+}e^{-}to Xi_c^0barXi_c^0$ process. We analyze the transverse polarization spontaneously produced in this process and spin transfer in the subsequent $Xi_c$ decays. The sensitivity to measure the asymmetry parameters are estimated for the decay $Xi_ctoXi pi$.
Using a successful framework for describing S-wave hadronic decays of light hyperons induced by a subprocess $s to u (bar u d)$, we presented recently a model-independent calculation of the amplitude and branching ratio for $Xi^-_b to Lambda_b pi^-$ in agreement with a LHCb measurement. The same quark process contributes to $Xi^0_c to Lambda_c pi^-$, while a second term from the subprocess $cs to cd$ has been related by Voloshin to differences among total decay rates of charmed baryons. We calculate this term and find it to have a magnitude approximately equal to the $s to u (bar u d)$ term. We argue for a negligible relative phase between these two contributions, potentially due to final state interactions. However, we do not know whether they interfere destructively or constructively. For constructive interference one predicts ${cal B}(Xi_c^0 to Lambda_c pi^-) = (1.94 pm 0.70)times 10^{-3}$ and ${cal B}(Xi_c^+ to Lambda_c pi^0) = (3.86 pm 1.35)times 10^{-3}$. For destructive interference, the respective branching fractions are expected to be less than about $10^{-4}$ and $2 times 10^{-4}$.
We evaluate the electromagnetic $Xi_c gamma rightarrowXi_c^prime$ transition on 2+1 flavor lattices corresponding to a pion mass of $sim 156$ MeV. We extract the magnetic Sachs and Pauli form factors which give the $Xi_c$-$Xi_c^prime$ transition magnetic moment and the decay rates of $Xi_c^prime$ baryons. We did not find a signal for the magnetic form factor of the neutral transition $Xi_c^0 gamma rightarrowXi_c^{prime 0}$, which is suppressed by the U-spin flavor symmetry. As a byproduct, we extract the magnetic form factors and the magnetic moments of $Xi_c$ and $Xi_c^prime$ baryons, which give an insight to the dynamics of $u/d$, $s$ and $c$ quarks having masses at different scales.
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