Electromagnetic form factors of spin- 1/2 doubly charmed baryons

Abstract

We study the electromagnetic form factors of the doubly charmed baryons, using covariant chiral perturbation theory within the extended on-mass-shell (EOMS) scheme. Vector-meson contributions are also taken into account. We present results for the baryon magnetic moments, charge and magnetic radii. While some of the chiral Lagrangian parameters could be set to values determined in previous works, the available lattice results for Ξ + cc and Ω + cc only allow for robust constraints on the low-energy constant (LEC) combination, c 89 (= − 1 3 c 8 + 4c 9 ). The couplings of the doubly charmed baryons to the vector mesons have been estimated assuming the Okubo-Zweig-Iizuka (OZI) rule. We also give the expressions for the form factors of the double beauty baryons considering the masses predicted in the framework of quark models. A comparison of our results with those obtained in heavy baryon chiral perturbation theory (HBChPT) at the same chiral order is made. * hillerbl@uni-mainz.de † LHCb [7] could confirm the existence of this state.On the other hand, the mass of Ξ ++ cc measured by LHCb is greater by more than 100 MeV than that of the Ξ + cc (3520) particle. This large splitting, if confirmed, would suggest that the two states are not isospin partners [8] and thus could belong to different multiplets.The scarce and conflicting experimental information has not deterred the theoretical research on the topic. Since the early works predicting the existence of doubly charmed baryons [9, 10], soon after the discovery of hidden (cc) charm states, these particles have been studied in quark models, QCD sum rules, lattice simulations, effective theories implementing heavy quark spin symmetry, etc. See, e.g., Refs. [11,12]. Most of those works address the spectroscopy of these baryons.Besides, other matters such as their decays [13-16] and electromagnetic properties have been abundantly studied. For instance, diverse quark models [17][18][19][20][21][22][23][24], the MIT bag model [25,26], the skyrmion model [27], HBChPT [28] and ChPT within the EOMS scheme [29] have been applied to study the magnetic moments of doubly charmed baryons. Both, the magnetic and the electric form factors (FF) have also been investigated in lattice QCD [30][31][32]. As expected, the lattice results show that the doubly charmed baryons have smaller radii than the singly charmed ones and than those composed of only light quarks such as the proton. However, there is some tension between the lattice results for magnetic moments and those determined in other theoretical models [31].Here, we focus on these FF, which are a quite interesting probe, as they offer an insight on the hadron structure and how its constituents are distributed.Our work is based on chiral perturbation theory (ChPT) [33][34][35][36], which provides a model independent and systematic framework to study the non-perturbative regime of the strong interaction at low energies or for soft probes. Furthermore, it is well suited to analyse the lattice data at quark(meson) masses different...

Properties of Doubly Heavy Baryons

“…The numerical results are shown in Table 5 for all doubly heavy baryon system. The obtained results are in accordance with the works in [53][54][55][56][57][58][59][60][61][62].…”

Radiative transitions and magnetic moments of the charmed and bottom vector mesons in chiral perturbation theory

“…Here, we adopt the SU(3) chiral perturbation theory (χPT) to investigate the radiative decay properties and magnetic moments of the D Ã and B Ã mesons. The framework of χPT has been widely used to study the radiative decays and magnetic moments of the charmed and bottom vector mesons 1 [28][29][30][31], the octet baryons [34,35], the doubly charmed and bottom heavy baryons [36][37][38][39], and the singly heavy baryons [40][41][42][43], as well as the related chiral quark-soliton model for singly heavy baryons [44,45]. In our calculations, we construct the effective Lagrangians with chiral symmetry and heavy quark symmetry up to Oðp 4 Þ.…”

Bound state formation in the DDK system

“…In this line, experimental and theoretical efforts, during the past years, have been dedicated to the study of doubly charmed baryons, like Ξ þ cc , Ξ þþ cc , Ω þ cc (see, for example, Refs. [3][4][5][6][7][8][9][10][11][12][13][14][15][16]), and doubly charmed mesons, like the T cc family and others (see, for example, Refs. [17][18][19][20][21][22][23][24][25][26][27]).…”