July 31, 2018 to August 6, 2018
Maynooth University
Europe/Dublin timezone

$\Omega_c$ excited states with heavy-quark spin symmetry

Aug 1, 2018, 4:00 PM
Hall H (Arts Bldg.)

Hall H

Arts Bldg.

Talk C: Heavy quarks Heavy quarks


Dr Laura Tolos (University of Frankfurt)


We study the $C=1$, $S=-2$, $I=0$ sector, where five $\Omega_c$ states have been recently observed by the LHCb Collaboration [1]. In Ref. [2] a unitarized meson-baryon model was solved by adopting a one-subtraction renormalization scheme taking, as bare meson-baryon interaction, an extended Weinberg-Tomozawa interaction consistent with both chiral and heavy-quark spin symmetries. This ${\rm SU(6)} \times$HQSS scheme lead to a successful description of the observed lowest-lying odd parity charmed $\Lambda_c(2595)$ and $\Lambda_c(2625)$ states [2], and bottomed $\Lambda_b(5912)$ and $\Lambda_b(5920)$ resonances [3]. In the $C=1$, $S=-2$, $I=0$ sector, five odd-parity $\Omega_c$ states were dynamically generated, but with masses below 3 GeV, not allowing for an identification with the observed LHCb resonances [2]. Recently we have revised this model and explored two different scenarios for the renormalization scheme, that is, using a modified common energy scale to perform the subtractions or utilizing a common UV cutoff to render finite the UV divergent loop functions in all channels. In both cases, we show that some (at least three) of the dynamically generated states can be identified with the experimental $\Omega_c$, while having odd parity and $J=1/2$ or $J=3/2$. Two of these states turn out to be part of the same ${\rm SU(6)} \times$HQSS multiplets as the charmed and bottomed $\Lambda$ baryons [4].

[1] R. Aaij et al. [LHCb Collaboration], Phys. Rev. Lett. 118, 182001 (2017)
[2] O. Romanets, L. Tolos, C. Garcia-Recio, J. Nieves, L.L. Salcedo and R.G.E. Timmermans, Phys. Rev. D 85, 114032 (2012)
[3] C. Garcia-Recio, J. Nieves, O. Romanets, L.L. Salcedo and L. Tolos, Phys. Rev. D 87, 034032 (2013)
[4] J. Nieves, R. Pavao and L. Tolos, Eur. Phys. J. C 78, 114 (2018)

Primary authors

Juan M Nieves (IFIC (CSIC-UV)) Mr Rafael Pavao (IFIC (CSIC-UV)) Dr Laura Tolos (University of Frankfurt)

Presentation materials