Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userQuantum Numbers of Recently Discovered $Omega^{0}_{c}$ Baryons from Lattice QCD
122
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We present the ground and excited state spectra of $Omega^{0}_{c}$ baryons with spin up to 7/2 from lattice quantum chromodynamics with dynamical quark fields. Based on our lattice results, we predict the quantum numbers of five $Omega^{0}_{c}$ baryons, which have recently been observed by the LHCb Collaboration. Our results strongly indicate that the observed states $Omega_c(3000)^0$ and $Omega_c(3050)^0$ have spin-parity $J^P = 1/2^{-}$, the states $Omega_c(3066)^0$ and $Omega_c(3090)^0$ have $J^P = 3/2^{-}$, whereas $Omega_c(3119)^0$ is possibly a $5/2^{-}$ state.
rate research
Read More
We calculate BSM hadronic matrix elements for $K^0-bar K^0$ mixing in the Dual QCD approach (DQCD). The ETM, SWME and RBC-UKQCD lattice collaborations find the matrix elements of the BSM density-density operators $mathcal{O}_i$ with $i=2-5$ to be rather different from their vacuum insertion values (VIA) with $B_2approx 0.5$, $B_3approx B_5approx 0.7$ and $B_4approx 0.9$ at $mu=3~GeV$ to be compared with $B_i=1$ in the VIA. We demonstrate that this pattern can be reconstructed within the DQCD through the non-perturbative meson evolution from very low scales, where factorization of matrix elements is valid, to scales of order $(1~GeV)$ with subsequent perturbative quark-gluon evolution to $mu=3~GeV$. This turns out to be possible in spite of a very different pattern displayed at low scales with $B_2=1.2$, $B_3=3.0$, $B_4=1.0$ and $B_5approx 0.2$ in the large $N$ limit, $N$ being the number of colours. Our results imply that the inclusion of meson evolution in the phenomenology of any non-leptonic transition like $K^0-bar K^0$ mixing and $Ktopipi$ decays is mandatory. While meson evolution, as demonstrated in our paper, is hidden in LQCD results, to our knowledge DQCD is the only analytic approach for non-leptonic transitions and decays which takes this important QCD dynamics into account.
We extract directly (for the first time) the charmed (C=1) and bottom (B=-1) heavy-baryons (spin 1/2 and 3/2) mass-splittings due to SU(3) breaking using double ratios of QCD spectral sum rules (QSSR) in full QCD, which are less sensitive to the exact value and definition of the heavy quark mass, to the perturbative radiative corrections and to the QCD continuum contributions than the simple ratios commonly used for determining the heavy baryon masses. Noticing that most of the mass-splittings are mainly controlled by the ratio kappa= <bar ss>/<bar dd> of the condensate, we extract this ratio, by allowing 1 sigma deviation from the observed masses of the Xi_{c,b} and of the Omega_c. We obtain: kappa=0.74(3), which improves the existing estimates: kappa=0.70(10) from light hadrons. Using this value, we deduce M_{Omega_b}=6078.5(27.4) MeV which agrees with the recent CDF data but disagrees by 2.4 sigma with the one from D0. Predictions of the Xi_Q and of the spectra of spin 3/2 baryons containing one or two strange quark are given in Table 2. Predictions of the hyperfine splittings Omega*_Q- Omega_Q and Xi*_Q-Xi_Q are also given in Table 3. Starting for a general choice of the interpolating currents for the spin 1/2 baryons, our analysis favours the optimal value of the mixing angle b= (-1/5 -- 0) found from light and non-strange heavy baryons.
We present a precise lattice QCD determination of the b-quark mass, of the B and Bs decay constants and first results for the B-meson bag parameters. For our computation we employ the so-called ratio method and our results benefit from the use of improved interpolating operators for the B-mesons. QCD calculations are performed with Nf = 2 dynamical light-quarks at four values of the lattice spacing and the results are extrapolated to the continuum limit. The preliminary results are mb(mb) = 4.35(12) GeV for the MSbar b-quark mass, fBs = 234(6) MeV and fB = 197(10) MeV for the B-meson decay constants, BBs(mb) = 0.90(5) and BB(mb) = 0.87(5) for the B-meson bag parameters.
Recently a novel hadronic state of mass 6.9 GeV, that decays mainly to a pair of charmonia, was observed in LHCb. The data also reveals a broader structure centered around 6490 MeV and suggests another unconfirmed resonance centered at around 7240 MeV, very near to the threshold of two doubly charmed $Xi_{cc}$ baryons. We argue in this note that these exotic hadrons are genuine tetraquarks and not molecules of charmonia. It is conjectured that they are V-baryonium tetraquarks, namely, have an inner structure of a baryonic vertex with a $cc$ diquark attached to it, which is connected by a string to an anti-baryonic vertex with a $bar c bar c$ anti-diquark. We examine these states as the analogs of the states $Psi(4360)$ and $Y(4630)$/$Psi(4660)$ which are charmonium-like tetraquarks. One way to test these claims is by searching for a significant decay of the state at 7.2 GeV into $Xi_{cc}overlineXi_{cc}$. Such a decay would be the analog of the decay of the state $Y(4630)$ into to $Lambda_coverlineLambda_c$. We further argue that there should be trajectories of both orbital and radial excited states of the $X(6900)$. We predict their masses. It is possible that a few of these states have already been seen by LHCb.
We present the energy spectra of the low lying doubly-charmed baryons using lattice quantum chromodynamics. We precisely predict the ground state mass of the charmed-strange Omega(cc) (1/2+) baryon to be 3712(11)(12) MeV which could well be the next doubly-charmed baryon to be discovered at the LHCb experiment at CERN. We also predict masses of other doubly-charmed strange baryons with quantum numbers 3/2+, 1/2-, and 3/2-.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
